Anesthesia for High Risk Patients

8/10/2019 Anesthesia for High Risk Patients

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Physiologic Changes of Aging

Cardiovascular

Arteries stiffen with agepulse pressure waveformaugmentedearly diastole to late systole

faster propagation

diastolic,systolic pressurepulse pressure

Slower myocardial relaxation and ventricular hypertrophy

late diastolic filling

diastolic dysfunction

Reduced venous capacitance

vascular reserve volume available to buffer hemorrhage

Reduced baroreceptor reflexes

sympathetic tone

parasympathetic tone

baroreceptor sensitivity

responsiveness to -adrenergic stimulation

Decreased maximal heart rate with age while stroke volume remain constant

Decreased maximal oxygen consumption

reduction in arteriovenous oxygen tension differences

Hypotension:

volume, position

anesthetic depth

RA-induced sympathetic b


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Respiratory


Parenchymal changes

30% of alveolar tissue is lost between ages 20 and 80

diminishing elastic recoil and parenchymal fractionairway patency

Residual volume, Closing volume and FRC

VC and FEV1progressive V/Q mismatchingage-dependent decrease in arterial O2tensio Physiologic dead space

Diffusing capacity

Chest wall changesStiffer chest wall

respiratory muscles

Depressed ventilatory response to hypoxia and hypercarbiaDecreased protective airway reflexes

aspiration risk


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Renal

Serum creatinine remains stable

age-associated decreases of creatinine clearance offset by reduced creatinine productio

normal creatinine levelabsence of renal impairment ?

Progressive atrophy of renal parenchyma and sclerosis of vasculature structuresRBF

GFR

Reduced ability to correct alteration :

electrolyte concentrations

intravascular volume

free waterReduced GFR

delayed renal drug excretion


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Physiologic changes of aging

Central Nervous System

Progressive loss of neurons

Decreased neurotransmitter activity

Cerebral autoregulatory response to BP, CO2and O2maintained

anesthetic requirement


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Hepatic

Liver mass

proportional reduction of sphlancnic and hepatic blood flow

hepatic drug clearance

Activity of some cytochrome P-450 isoforms

Phase 1 and phase 2 reactions


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Body composition and thermoregulation

Basal metabolism and heat production

skeletal muscle atrophy

adipose tissue

propensity of hypothermia

blunted central thermoregulation

body composition changes

muscle mass and total body water, body fat

Vd of water-soluble drugs

Vd of lipid-soluble drugs


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Pharmacologic Implications of Aging

binding site for most lipophilic basic drugs

alpha1-acid glycoprotein

frequency and severity of adverse drug reactions

MAC for inhalational anesthetic


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Anesthetic Considerations In The Elderly

Age-related coexisting disease is a major predictor for perioperative morbidity and mortaliage alone is a minor predictor

Major risk factors:

emergency surgery

operative site : major body cavity or vascular

ASA physical status

No significant difference:specific anesthetic agent

RA vs GA

functional reserve capacitytherapeutic index of anesthetic interventions

highly variable

unpredictable

may be manifest only under severe stress

vigilance

preparation for contingencies


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The leading cause of death

Risk factor identified to predict perioperative cardiac morbidity:

Recent myocardial infarction

The presence of congestive heart failure

Understanding the pathophysiology of the disease process

Careful selection of :

anesthetic drugsmonitors


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Coronary artery disease

Often asymptomatic

A common accompaniment of aging40% will either have or be at risk

morbidity and mortality

Routine preoperative cardiac evaluation:

historyPE

ECG

ambulatory ECG monitoring (Holter monitoring)

exercise stress testing

transthoracic or transesophageal echocardiography

radionuclide ventriculography

dypiridamole-thallium scintigraphy

cardiac catheterization

angiography

Select

patien

Best medical condition possible

before elective cardiac or non-cardiac surge


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Patient History

Cardiac reservelimited exercise tolerance in the absence of significant pulmonary disease

Characteristic of angina pectoris

stable : no change for at least 60 days in precipitating factors, frequency and duration

unstable

variant or prinzmetals : due to spasm of coronary arteries, may occurs at rest

dyspnea following the onset of angina

acute left ventricular dysfunction due to MIHR and/or SBPHR > SBP

The presence of a prior myocardial infarction

incidence of reinfarction in the perioperative period 4872 hrs postoperatively

related to the time elapsed since the previous MI

delay the elective surgery for about 6 mos after MI (56%), 50 x (n: 0.1

intrathoracic or intra-abdominal operations lasting longer than 3 hoursPotential drug interactions

Coexisting non-cardiac disease

Patient can remain asymptomatic despite 5070% stenosis of a major coronary arte


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Management of anesthesia

Modulation of SNS responses

Provide for the rigorous control of hemodynamic variables

Based on:

preoperative evaluation of left ventricular function

Maintenance of a favorable balance between myocardial O2requirement and deliv

tachycardia

systolic hypertension

arterial hypoxemia

diastolic hypotension

more important than the specific technique or drugs


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Induction of anesthesia

Rapidly acting IV drugs

Ketamineassociated with HR and SBP

not popular


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Tracheal intubation

facilitated by Succhinylcholine or Nondepolarizing MR

MI may accompany hypertension and tachycardia

brief duration (


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Maintenance of anesthesia

Choice of anesthesia

based on left ventricular function

CAD, but normal left ventricular function

SBP,HR in response to stimulation

volatile anesthetic with/withoutN2O

to control myocardial depression

N2Oopioid + volatile anesthetic

to treat acute in SBP

drug-inducedin SVR > drug-induced myocardial depressisoflurane

sevoflurane

desflurane

Low blood solubility

rapid


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Impaired left ventricular function

may not tolerate myocardial depression produced by volatile anesthetics

high dose opioid techniqueopioid + N2O technique

N2O, when combined with opioid

may produce undesirable in SBP and CO

Regional anesthesia

Flow through critically narrowed coronary arteries is pressure-dependent

SBP associated with RA > 20% of the pre-block

should be treated

fluids infusionsympathomimetic

ephedrine

phenylephine


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Monitoring

Complexity of the operative procedure

Severity of the coronary artery disease

ECG

non-invasive

balance between myocardial O2requirement and myocardial O2delivery

myocardial ischemiaS-T depression

V5 left ventricleTEE

ventricular wall motion abnormality

most sensitive indicator for MI

invasive and not practical

Pulmonary artery catheter

Central venous pressuremay not reliably reflect left heart filling pressure

in the presence of left ventricular dysfunction

For selected high risk patients

recent MI

CHF

unstable angina


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Signs of MI

aggressive treatment of adverse changes in HR and/or SBP

tachycardia

propanolol

esmolol

SBP

nitropruside

nitroglycerinemore appropriate choice when MI is associated with normal S

hypotension

sympathomimetics

to rapidly restore pressure-dependent perfusion

intravenous infusion of fluids

myocardial O2requirements for volume work < pressure work

pulmonary artery catheter

for monitoring responses of ventricular functio

Monitoring


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Postoperative care

Analgesia

Sedation

To blunt excessive SNS activity

Facilities vigorous control of hemodynamic variables

intensive and continuous monitoringto detect myocardial ischemia, which is often asymptomatic

! Identification and treatment

cardiac morbidity

Temperature

hypothermiashiveringabruptin myocardial O2requirement

minimize in body temperature

O2supplementation

Congestive Heart Failure


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Congestive Heart Failure

should not be performed as an elective surgery

Associated with postoperative morbidity

optimally treated

when surgery can not be delayedchose of drugs/techniques

goal : optimizing cardiac output

GA: induction : ketamine

maintenance: volatile anesthetic is not recommended

potential for cardiac depressionhigh dose opioid may be justified

positive pressure ventilationmay be beneficial

pulmonary congestion

improving oxygenation

invasive monitoring

continuous infusion of dopamine and/or dobutaminemaintenance of cardiac contractility

RA: for peripheral surgery

SVR secondary to peripheral SNS blockade

facilitate left ventricular stroke volume


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Essestial Hypertension

Sustained increases in systemic blood pressure independent of any known cau

systolic blood pressure > 160 mmHg

diastolic blood pressure > 90 mmHg

Tx with appropriate drugs

incidence of stroke and congestive heart failure

incidence of hypotension and MI on ECG during maintenance of anesthesia

in patient who remain hypertensive before the induction of anesthesia

SBP during intraoperative period

more likely to occur in patient with history of essential hypertension

regardless of the degree of pharmacology control of SBP preoperat

no evidence of postoperative cardiac complications

as long as preoperative diastolic BP is not higher than 110 mmHg


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Preoperative evaluation

adequacy of SBP controldrug therapy

!!! maintain current therapy throughout the perioperative period

extent of the disease

major organ dysfunctioninfluences drug selection

assumed to have coronary artery disease until proven otherwise

evidence of peripheral vascular disease

Consideration of the implications of exaggerated SBP responses

elicited by painful intraoperative stimulation

Shift to the right of the curve for the autoregulation of cerebral blood flow

more vulnerable to cerebral ischemiashould perfusion pressure decrease


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M i t f th i


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Adjust the concentration of anesthetic drugs

to minimize wide fluctuations in SBPmore important than preoperative control of hypertension

N2O + volatile anestheticfor rapid adjustment in the depth of anesthesia in response to or SBP

attenuating SNS, which is responsible for pressor responses

desflurane

sevoflurane

N2O + Opioid

the addition of a volatile anesthetic is often necessary to control undesirable

particularly during periods of maximal surgical stimulation

Nitroprusside

-Blockers : esmolol or labetalol

Low blood solubilities


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Hypotension that occurs during maintenance of anesthesia:the concentration of volatile anesthetics

IV fluids infusion

to intravascular fluid volume

sympathomimetics

to restore perfusion pressure until underlying cause can be corrected

ephedrine


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Regional anesthesia

Questionable choice

when high levels of SNS blockade would be associated with the sensory level

necessary for planned surgery

possibility of excessive decreases in SBP

vasodilatation unmasks a decreased intravascular fluid volumeassociated with chronic hypertension


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Choice of intra-operative monitors

Influenced by the complexity of the surgery

ECG

goal: recognizing changes suggestive of MI

invasive monitors: arterial and/or pulmonary catheters

if major surgery is planned

evidence of left ventricular dysfunction pre-operatively

Transesophageal echocardiography

an alternative to placement of a pulmonary artery catheter


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Postoperative management

Hypertension in the early postoperative period

frequent

adequate analgesia

pharmacologically decrease SBP

nitroprusside, continuous IVlabetalol (0.10.5 mg/kg/IV


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A challenge :

Intraoperative managementPostoperative management

Regardless of the operative site

particular risk:

thoracic

upper abdominal

Co-existing disease:

coronary artery disease

essential hypertension

OBSTRUCTIVE AIRWAY DISEASE


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Most frequent cause of pulmonary dysfunction

Chronic Obstructive Pulmonary Disease (COPD)

a group of disorders characterized by a persistent decrease in the maximum rate of exhala

despite aggressive therapy

regional differences in airway resistance

areas of ventilation-to-perfusion mismatching

arterial hypoxemia

CO2retentionrespiratory acidosis

cough and sputum production


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Symptom: dyspnea work of breathing

PE : wheezing during exhalationturbulence gas flow through narrowed airw

Chest X-ray : hyperinflated lung, radiolucencypulmonary blood flow

flattened diaphragm

Pulmonary function studies : expiratory flow ratesairway resistance

FEV1< 80%


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Bronchial asthma

Classic example of obstructive airway diseaseMost common chronic inflammatory disease of the airway

characterized by acute and reversible increases in airway resistanc

irreversibleCOPD

Chronic inflammatory changes in the submucosa of the airwayIncreased airway responsiveness (hyper-reactivity) to various stimuli

Reversible expiratory airflow obstruction


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Bronchial asthma

Clinical symptoms:during periods of normal to near normal pulmonary function

no physical findings

acute bronchial asthma attack

wheezing

cough

non productiveproduction of copious amount of tenacious sput

dyspneaparallel to the severity of expiratory airflow obstruction

FEV1: 2575% vital capacity

the flow-volume loopdownward scooping of the expiratory limb of the loop

B hi l th


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Bronchial asthma

Estimation of the severity of bronchial asthma

Expiratory airflow FEV1 PaO2 PaCO2Obstruction (% predicted) (mmHg) (mmHg

Mild (asymptomatic) 6580 > 60 < 40

Moderate 5064 > 60 < 45

Marked 3549 < 60 > 50

Severe (status asthmaticus) < 35 < 60 > 50

Bronchial asthma


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Preoperatively

absence of : dyspneawheezing

PFT indicated for a thoracic or abdominal operation

before and after bronchodilator therapy

ABG adequacy of ventilation or arterial oxygenation

persistent symptomstreated with glucocorticoids (inhaled or systemic)

continue throughout perioperative period

supplementation with cortisol

if suppresion of the hypothalamic-pituitary-adrenal axis is suspec

anticholinergicsindividualized

airway resistanceviscosity of the secretions

H2antagonistsantagonism of H2-mediated bronchodilation

unmask H -mediated bronchoconstriction

No acute exacerbation of bronchial asthma


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R id IV i d ti


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Rapid IV inductionThiopental

Etomidate

Propofol may blunt tracheal intubation-induced bronchospasm

Ketamine sympathomimetic effects on bronchial smooth muscleairway resistance

secretions

Before intubationsufficient depth should be established

Lidocaine (1 to 2 mg/kg/IV)

to blunt bronchoconstriction reflex

Sevoflurane

Isoflurane

Halothane

Depress airway reflexes

Do not sensitize the heart to the cardiac dysrhythmic effects of SNS stimulation

produced by -agonist and aminophylline

Bronchodilation effectsNO production

Bronchodilator

Associated with cardiac dysrhythmias in the presence of SNS stimulation


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Neuromuscular blocking drugs

not associated with endogenous histamine release

PaO2PaCO2

Maintained at normal levels

slow RR (6 to 10)

to allow adequate time for passive exhalationhigh inspiratory flow rate

PEEPmay not be ideal

adequate exhalation may be impaired

Liberal IV fluid administration

ensuring the presence of less viscous secretions


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At the conclusion of elective surgery

deep extubationanesthesia depth still sufficient to suppress hyperreactive airway reflexes

bronchospasm does not predictably follow administration of anticholinestera

Lidocaine/IV may decrease the likelihood of airway stimulation


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Intraoperative Bronchospasm

Deepening of anesthesia with volatile anesthetic

-2 agonist

Corticosteroids

Mechanical obstructionInsufficient anesthetic concentration

Pulmonary aspiration

Endobronchial intubation

Pneumothorax

Pulmonary embolusAcute bronchial asthma

?


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Pulmonary emphysema

Loss of elastic recoil of the lung

collapse of airways during exhalation

airway resistance

Severe dyspnea

work of breathing


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Determine the severity of the disease

Elucidate any reversible components

infections

bronchospasm


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PFTDo not always correlate with postoperative outcome

dyspnea

coughsputum production

exercise tolerance

ABGmay be normal (pink puffer)

high minute ventilation

to overcome airway resistance

PaCO2> 50 mmHgrisk of post operative respiratory failure


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Risk of postoperative respiratory failure:

vital capacity < 50% of the predicted value

FEV1< 50% of the predicted value

FEV1< 2 liters

Arterial hypoxemia and/or hypercarbia is present

!!!

preoperative detection and treatment of cor pulmonalesupplemental O2


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Does not dictate the use of specific drugs or techniques

Susceptible to the development of acute respiratory failure

in the postoperative period

continue tracheal intubation andmechanical ventilation of the lun


General anesthesia


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General anesthesia

humidified inhaled gases to prevent drying of secretions, systemic hydration

mechanical ventilation of the lung small tidal volumes

small breathing rates

N2O:

limitation of the inhaled concentration of oxygen

passage of this gas into bullae from emphysema

enlargement and rupturetension pneumothorax

Opioids:

less ideal for maintenance of anesthesia to ensure amnesia

need high concentration of N2O

substituting a low concentration of volatile anesthetic for N2O

postoperative ventilatory depression

chronic hypercarbia should not be abruptly corrected

inspiratory flow

Chronic Bronchitis


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Chronic Bronchitis

Chronic or recurrent secretion of excess mucus into the bronchii

resistance to gas flow through the airways

Tend to develop:

Arterial hypoxemia (blue bloaters)Hypercarbia

Cor pulmonaleearly

Small airway account to only a minor proportion of total airways resistancechronic bronchitis must be advanced before dyspnea become appare

Restrictive Pulmonary Disease


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y

Lung compliance

lung volume

vital capacity in the presence of a normal FEV1

Dyspneawork of breathing necessary to expand the poorly compliant lungs

Rapid and shallow breathing

to minimize the work of breathing in the presence of lung compliance

PaCO2hyperventilation

usually maintained at a decreased to normal value, until far advance

Severe Pulmonary hypertension

Acute restrictive pulmonary disease

l k f i t l fl id i t th i t titi d l li f th l


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leakage of intravascular fluid into the interstitium and alveoli of the lu

pulmonary edema

Acute Respiratory Distress Syndrome

Aspiration pneumonitisNeurogenic pulmonary edema

Opioid-induced pulmonary edema

High-altitude pulmonary edema

Chronic restrictive pulmonary disease

presence of pulmonary fibrosis (sarcoidosis)

processes that interfere with expansion of the lungs

Effusions

KyphoscoliosisObesity

Ascites

Pregnancy



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RA

appropriate for peripheral surgery

sensory level above T10

associated with the impairment of respiratory muscle activity

GAdoes not influence the choice of drugs used for induction or maintenance

mechanical ventilation is useful

high inflation pressures may be necessary

minimize ventilatory depression that may persist into postoperative period

vital capacity < 15 mL/kg

PaCO2 > 50 mmHgdifficult to generate effective cough

preoperatively


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Effect of Anesthesia on Renal FunctionIndirect effects


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Cardiovascular effects

inhalational and intravenous agents

cardiac depressionvasodilatation

RA

sympathetic block

Neural effects

sympathetic activation

light anesthesiaintense surgical stimulation

tissue trauma

anesthetic-induced circulatory depression

Endocrine effects

stress response

surgical stimulation

circulatory depression

hypoxia

acidosis

BP,Below the limit of autoregulation:

RBF, GFR, urinary flow, Na+excret

IV fluid administration

Renal vascular resistanceActivates hormonal system

RBF, GFR, UO

Catecholamines

Renin, Angiotensin II, Aldosterone

ADH

ACTH, Cortisol

Effect of Anesthesia on Renal Function


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Direct effects minor

Volatile agents

Methoxyfluranepolyuric renal failure

defect in urinary concentrating ability

dose-related1 MAC for 2 hrs

release of fluoride ions ( > 50 mol/L )

Enflurane, Sevoflurane (possible)prolonged administration

fluoride excretion: GFR dependent

preexisting renal impairmentmore susceptible

Compound A: breakdown product of sevoflurane

FGF > 2 L/min

Halothane, Isoflurane, and Desfluranenegligible



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Intravenous agents

opioids and barbiturate minor effect when used alone

+ N2O volatine agents

ketamineminimally affect renal function

preserve renal function during hemorrhagic hypovolemia

-adrenergic blocking agents(droperidol)prevent catecholamine-induced redistribution of RBF

antidopaminergic agents(metoclopramine, phenothiazines, droperidol)impair renal response to dopamine

NSAIDs (ketorolac)prevent renal production of vasodilatory prostaglandins

ACE inhibitors

block the protective effects of angiotensin IIGFR



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Other drugs

antibiotics

aminoglycosides, amphotericine B

imunosupressive agents

cyclosporin

radiocontrast dyes

renal arterial vasospasm

direct cytotoxic properties

renal microvascular or tubular obstruction

preexisting renal dysfunction!

Effect of Specific Surgical Procedures on Renal Functio


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Laparoscopy procedures

Pneumoperitoneum

abdominal compartement syndrome-like state

intraabdominal pressure insufflation pressures

central venous compression (renal vein and vena cava)

renal parenchymal compression

cardiac output

plasma renin, aldosterone and ADH

oliguria/anuria

Cardiopulmonary bypass

Cross-clamping of the aorta

Dissection near the renal arteriesNeurosurgical procedureADH


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Management of Anesthesia


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Tracheal intubation

CRF (regardless of hydration status)

hypovolemic

risk of hypotension

if SNS function is attenuated by antihypertensive therapy

impairs compensatory peripheral vasoconstriction

small decrease in blood volume

positive pressure ventilation

sudden change in body position

common IV drugs

Muscle relaxants

Succinyl choline


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Succinyl choline

acceptableassuming preexisting hyperkalemia is not present

Non-depolarizing MRnot dependent on renal clearance

intermediate and short acting

atracurium and cisatracuriumlaudanosineclearance delayed

initial dose

Administer subsequent dose based on the response to PNSConsider drug interaction

antibiotics, acidosis, electrolyte imbalance


N O


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N2O

FiO2?

Volatile anestheticscontrolling intraoperative hypertension

dose of MR

Desflurane

Isoflurane

Opioid

CV depression

avoid hepatotoxicity and nephrotoxicity

unreliable for controlling intraoperative hypertension

prolonged CNS & respiratory depressionaccumulation of pharmacologically active metabolites

V til ti


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Ventilation

Normocapnia is desirable

Hyperventilation

respiratory alkalosisoxyhemoglobin dissociation curve

Hypoventilationrespiratory acidosisK+

Fluid Management


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Hemodialysis dependent

narrow margin of safety :insufficient vs excessive fluid administration

replacement of insensible losses (including UO)0.9% saline

potassium-containing fluidsshould not administered to anuric patients

CVP measurementguiding fluid replacement

ECG monitoringfor recognizing signs of hyperkalemia

AV shuntsmust be carefully protected

Postoperaive period


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Postoperaive period

Hypertension

frequent problem

hemodialysis is the best treatment if fluid excess is the cau

Opioid for postoperative analgesia

possibility of exagerated CNS and respiratory depression

regional analgesia

adequacy of coagulation?

presence of uremic neuropathies?

metabolic acidosis?

seizure threshold for local anesthetics


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A challenge :


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A challenge :

Intraoperative management

Postoperative management Regardless of the operative siteparticular risk:thoracic

upper abdominal

Co-existing disease:coronary artery disease

essential hypertension



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Most frequent cause of pulmonary dysfunction

Chronic Obstructive Pulmonary Disease (COPD)

a group of disorders characterized by a persistent decrease in the maximum rate of exhala

despite aggressive therapy

regional differences in airway resistanceareas of ventilation-to-perfusion mismatching

arterial hypoxemia

CO2retentionrespiratory acidosis

cough and sputum production

S t d k f b thi


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Symptom: dyspnea work of breathing

PE : wheezing during exhalationturbulence gas flow through narrowed airw

Chest X-ray : hyperinflated lung, radiolucencypulmonary blood flow

flattened diaphragm

Pulmonary function studies : expiratory flow ratesairway resistance

FEV1< 80%

Bronchial asthma


75/167

Classic example of obstructive airway diseaseMost common chronic inflammatory disease of the airway

characterized by acute and reversible increases in airway resistanc

irreversibleCOPD

Chronic inflammatory changes in the submucosa of the airwayIncreased airway responsiveness (hyper-reactivity) to various stimuli

Reversible expiratory airflow obstruction


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Bronchial asthma


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Estimation of the severity of bronchial asthma

Expiratory airflow FEV1 PaO2 PaCO2Obstruction (% predicted) (mmHg) (mmHg

Mild (asymptomatic) 6580 > 60 < 40

Moderate 5064 > 60 < 45

Marked 3549 < 60 > 50

Severe (status asthmaticus) < 35 < 60 > 50


Bronchial asthma


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Preoperativelyabsence of : dyspnea

wheezing

PFT indicated for a thoracic or abdominal operation

before and after bronchodilator therapy

ABG adequacy of ventilation or arterial oxygenation

persistent symptomstreated with glucocorticoids (inhaled or systemic)

continue throughout perioperative period

supplementation with cortisol

if suppresion of the hypothalamic-pituitary-adrenal axis is suspec

anticholinergicsindividualized

airway resistanceviscosity of the secretions

H2antagonistsantagonism of H2-mediated bronchodilation

unmask H -mediated bronchoconstriction

No acute exacerbation of bronchial asthma

Choice of anesthesia


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Regional anesthesia

an attractive choice

superficial or extremities surgery

General anesthesiainduction

maintenanceSuppression of airway reflexes

avoid bronchoconstriction of hyperreactive airways

in response to mechanical stimulation

Rapid IV inductionThiopental

Et id t


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Etomidate

Propofol may blunt tracheal intubation-induced bronchospasm

Ketamine sympathomimetic effects on bronchial smooth muscle

airway resistance

secretions

Before intubationsufficient depth should be established

Lidocaine (1 to 2 mg/kg/IV)

to blunt bronchoconstriction reflex

Sevoflurane

Isoflurane

Halothane

Depress airway reflexes

Do not sensitize the heart to the cardiac dysrhythmic effects of SNS stimulation

produced by -agonist and aminophylline

Bronchodilation effectsNO production

BronchodilatorAssociated with cardiac dysrhythmias in the presence of SNS stimulation


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deep extubation

anesthesia depth still sufficient to suppress hyperreactive airway reflexes

bronchospasm does not predictably follow administration of anticholinestera

Lidocaine/IV may decrease the likelihood of airway stimulation

Intraoperative Bronchospasm


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Deepening of anesthesia with volatile anesthetic

-2 agonist

Corticosteroids

Mechanical obstructionInsufficient anesthetic concentration

Pulmonary aspiration

Endobronchial intubation

Pneumothorax

Pulmonary embolusAcute bronchial asthma

?

Pulmonary emphysema


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Loss of elastic recoil of the lung

collapse of airways during exhalation

airway resistance

Severe dyspnea

work of breathing



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Determine the severity of the disease

Elucidate any reversible components

infections

bronchospasm


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Risk of postoperative respiratory failure:


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s o postope at ve esp ato y a u e:

vital capacity < 50% of the predicted value

FEV1< 50% of the predicted value

FEV1< 2 liters

Arterial hypoxemia and/or hypercarbia is present

!!!

preoperative detection and treatment of cor pulmonale

supplemental O2



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Does not dictate the use of specific drugs or techniques

Susceptible to the development of acute respiratory failure

in the postoperative period

continue tracheal intubation andmechanical ventilation of the lun

Management of anesthesiaGeneral anesthesia

humidified inhaled gases to prevent drying of secretions, systemic hydration

h i l til ti f th l ll id l l


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mechanical ventilation of the lung small tidal volumessmall breathing rates

N2O:

limitation of the inhaled concentration of oxygen

passage of this gas into bullae from emphysema

enlargement and rupture

tension pneumothorax

Opioids:

less ideal for maintenance of anesthesia to ensure amnesia

need high concentration of N2O

substituting a low concentration of volatile anesthetic for N2Opostoperative ventilatory depression

chronic hypercarbia should not be abruptly corrected

inspiratory flow

Chronic Bronchitis


90/167

Chronic or recurrent secretion of excess mucus into the bronchii

resistance to gas flow through the airways

Tend to develop:

Arterial hypoxemia (blue bloaters)Hypercarbia

Cor pulmonaleearly

Small airway account to only a minor proportion of total airways resistancechronic bronchitis must be advanced before dyspnea become appare

Restrictive Pulmonary Disease


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Lung compliance

lung volume

vital capacity in the presence of a normal FEV1

Dyspnea

work of breathing necessary to expand the poorly compliant lungsRapid and shallow breathing

to minimize the work of breathing in the presence of lung compliance

PaCO2hyperventilation

usually maintained at a decreased to normal value, until far advance

Severe Pulmonary hypertension

Acute restrictive pulmonary disease

leakage of intravascular fluid into the interstitium and alveoli of the lu

pulmonary edema


92/167

p y

Acute Respiratory Distress Syndrome

Aspiration pneumonitisNeurogenic pulmonary edema

Opioid-induced pulmonary edema

High-altitude pulmonary edema

Chronic restrictive pulmonary diseasepresence of pulmonary fibrosis (sarcoidosis)

processes that interfere with expansion of the lungs

Effusions

Kyphoscoliosis

Obesity

Ascites

Pregnancy



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RAappropriate for peripheral surgery

sensory level above T10

associated with the impairment of respiratory muscle activity

GA

does not influence the choice of drugs used for induction or maintenance

mechanical ventilation is useful

high inflation pressures may be necessary

minimize ventilatory depression that may persist into postoperative period

vital capacity < 15 mL/kg

PaCO2 > 50 mmHg

difficult to generate effective cough

preoperatively


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The leading cause of death


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Risk factor identified to predict perioperative cardiac morbidity:

Recent myocardial infarction

The presence of congestive heart failure

Understanding the pathophysiology of the disease process

Careful selection of :

anesthetic drugs

monitors


Often asymptomatic


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y p

A common accompaniment of aging

40% will either have or be at riskmorbidity and mortality

Routine preoperative cardiac evaluation:

history

PEECG

ambulatory ECG monitoring (Holter monitoring)

exercise stress testing

transthoracic or transesophageal echocardiography

radionuclide ventriculography

dypiridamole-thallium scintigraphycardiac catheterization

angiography

Select

patien

Best medical condition possible

before elective cardiac or non-cardiac surge

Coronary artery diseasePatient History

Cardiac reser e


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Cardiac reservelimited exercise tolerance in the absence of significant pulmonary disease

Characteristic of angina pectorisstable : no change for at least 60 days in precipitating factors, frequency and duration

unstable

variant or prinzmetals : due to spasm of coronary arteries, may occurs at rest

dyspnea following the onset of anginaacute left ventricular dysfunction due to MI

HR and/or SBPHR > SBP

The presence of a prior myocardial infarction

incidence of reinfarction in the perioperative period 4872 hrs postoperatively

related to the time elapsed since the previous MI

delay the elective surgery for about 6 mos after MI (56%), 50 x (n: 0.1

intrathoracic or intra-abdominal operations lasting longer than 3 hours

Potential drug interactionsCoexisting non-cardiac disease

Patient can remain asymptomatic despite 5070% stenosis of a major coronary arte


ECG


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Myocardial ischemia

S-T segment depression > 1 mm

Prior myocardial infarction

Cardiac hyperthrophy

Abnormal cardiac rhythm and/or conduction

Electrolyte abnormalities

Exercise ECG

stimulates SNS

direct laryngoscopy

tracheal intubation

surgical incision

Resting ECG in the absence of angina pectoris may be normal despite extensive CAD




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g

Modulation of SNS responses

Provide for the rigorous control of hemodynamic variables

Based on:

preoperative evaluation of left ventricular function

Maintenance of a favorable balance between myocardial O2requirement and deliv

tachycardia

systolic hypertension

arterial hypoxemia

diastolic hypotension

more important than the specific technique or drugs



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Preoperative medication

to produce sedation

to allay anxiety

if unopposedcatecholamine secretion

myocardial O2requirements

SBPHR

benzodiazepine

scopolamine + morphine

transdermal nitrogycerine




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Rapidly acting IV drugs

Ketamineassociated with HR and SBP

not popular


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Choice of anesthesiabased on left ventricular function

CAD, but normal left ventricular function

SBP,HR in response to stimulation

volatile anesthetic with/withoutN2O

to control myocardial depression

N2Oopioid + volatile anesthetic

to treat acute in SBP

drug-inducedin SVR > drug-induced myocardial depress

isofluranesevoflurane

desflurane

Low blood solubilityrapid

Impaired left ventricular function

may not tolerate myocardial depression produced by volatile anesthetics

hi h d i id t h i


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high dose opioid technique

opioid + N2

O technique

N2O, when combined with opioid

may produce undesirable in SBP and CO

Regional anesthesia

Flow through critically narrowed coronary arteries is pressure-dependent

SBP associated with RA > 20% of the pre-block

should be treated

fluids infusion

sympathomimeticephedrine

phenylephine

Isoflurane

more potent coronary arteriole vasodilator than sevoflurane or desflurane

ld di bl d fl


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could divert blood flow

from ischemic areas to non-ischemic area of myocardiumcoronary artery steal

Volatile anestheticsmyocardial O2requirement

SBP

coronary perfusion pressure

coronary artery steal

Monitoring

Complexity of the operative procedure

Severity of the coronary artery disease


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ECG

non-invasive

balance between myocardial O2requirement and myocardial O2delivery

myocardial ischemiaS-T depression

V5 left ventricle

TEEventricular wall motion abnormality

most sensitive indicator for MI

invasive and not practical


Central venous pressure

may not reliably reflect left heart filling pressurein the presence of left ventricular dysfunction

For selected high risk patients

recent MI

CHF

unstable angina


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Postoperative care

Analgesia


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Sedation

To blunt excessive SNS activity

Facilities vigorous control of hemodynamic variables

intensive and continuous monitoring

to detect myocardial ischemia, which is often asymptomatic

! Identification and treatment

cardiac morbidity

Temperature

hypothermiashivering

abruptin myocardial O2requirementminimize in body temperature

O2supplementation

Congestive Heart Failureshould not be performed as an elective surgery

Associated with postoperative morbidity

optimally treated

when surgery can not be delayed


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when surgery can not be delayed

chose of drugs/techniques

goal : optimizing cardiac output

GA: induction : ketamine

maintenance: volatile anesthetic is not recommended

potential for cardiac depression

high dose opioid may be justified

positive pressure ventilationmay be beneficial

pulmonary congestion

improving oxygenation

invasive monitoring

continuous infusion of dopamine and/or dobutamine

maintenance of cardiac contractilityRA: for peripheral surgery

SVR secondary to peripheral SNS blockade

facilitate left ventricular stroke volume

Essestial Hypertension

Sustained increases in systemic blood pressure independent of any known cau


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systolic blood pressure > 160 mmHg

diastolic blood pressure > 90 mmHg

Tx with appropriate drugs

incidence of stroke and congestive heart failure

incidence of hypotension and MI on ECG during maintenance of anesthesia

in patient who remain hypertensive before the induction of anesthesia

SBP during intraoperative period

more likely to occur in patient with history of essential hypertension

regardless of the degree of pharmacology control of SBP preoperatno evidence of postoperative cardiac complications

as long as preoperative diastolic BP is not higher than 110 mmHg



d f SBP l


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adequacy of SBP control

drug therapy!!! maintain current therapy throughout the perioperative period

extent of the disease

major organ dysfunctioninfluences drug selection

assumed to have coronary artery disease until proven otherwise

evidence of peripheral vascular disease

Consideration of the implications of exaggerated SBP responses

elicited by painful intraoperative stimulation

Shift to the right of the curve for the autoregulation of cerebral blood flowmore vulnerable to cerebral ischemiashould perfusion pressure decrease



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Exaggerated decrease in SBP may occur

unmasking of decrease intravascular fluid volume due to chronic hypertensionparticularly if hypertension is present preoperatively

Ketamine rarely selected

Exagerated increase in SBPduring direct laryngoscopy are predictableMI

ensure maximal attenuation of SNS responses evoked by DL

volatile anesthetics

IV opioids

lidocaine

limit the duration of DL < 15 sec, if possible

Undesirable hypotension


Adjust the concentration of anesthetic drugs

to minimize wide fluctuations in SBP


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to minimize wide fluctuations in SBP

more important than preoperative control of hypertension

N2O + volatile anestheticfor rapid adjustment in the depth of anesthesia in response to or SBP

attenuating SNS, which is responsible for pressor responses

desfluranesevoflurane

N2O + Opioid

the addition of a volatile anesthetic is often necessary to control undesirable

particularly during periods of maximal surgical stimulation

Nitroprusside

-Blockers : esmolol or labetalol

Low blood solubilities


Hypotension that occurs during maintenance of anesthesia:


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the concentration of volatile anestheticsIV fluids infusion

to intravascular fluid volume

sympathomimetics

to restore perfusion pressure until underlying cause can be corrected

ephedrine

Regional anesthesia


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Questionable choicewhen high levels of SNS blockade would be associated with the sensory level

necessary for planned surgery

possibility of excessive decreases in SBP

vasodilatation unmasks a decreased intravascular fluid volume

associated with chronic hypertension


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Postoperative management


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Hypertension in the early postoperative periodfrequent

adequate analgesia

pharmacologically decrease SBP

nitroprusside, continuous IV

labetalol (0.10.5 mg/kg/IV


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Disorder of endocrine gland function:

May be the primary reason for surgery


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y p y g y

May co-exist in patient requiring operation unrelated to the disorder

Preoperative evaluation of endocrine function:

Absence of glucose in the urineSBP and HR normal

Body weight unchanged

Sexual function normal

No history of relevant drug therapy

Diabetes Mellitus


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The most common endocrine disease in surgical patients

Broad range of severity

The manifestation can be altered in response to stress

Chronic systemic disease

An array of abnormalities, the most notable of which is

disturbed glucose metabolism resulting inappropriate hyperglycemia


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Pre-operative

Should be in the best state of metabolic control that is possible preoperative

History and PE

detect symptoms of CVD, CAD, peripheral neuropathy

Laboratory test


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Laboratory test

ECG

blood glucose, creatinine and potassium levels

urinalysis (glucose, ketones, albumin)

Evidence of stiff joint syndrome

difficult to perform laryngoscopy

Evidence of cardiac autonomic nervous system neuropathyresting tachycardia, orthostatic hypotension, absent variation in HR w/ deep breath

prevent development of angina pectoris (painless MI)

risk of sudden death, cardiovascular lability

Evidence of vagal autonomic nervous system neuropathy

gastroparesisrisk of aspiration of gastric contentEvidence of peripheral neuropathy

more susceptible to compression injury

Preoperative evaluation and treatment

hyperglycemia

ketoacidosis

electrolyte imbalance


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Hba1c

manifestation of :

coronary artery disease

cerebral vascular disease

renal dysfunction

Should be scheduled for surgery early in the morning

Well controlled, diet treated NIDDM

does not require special treatment before and during surgery


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Well controlled IDDMbrief, out-patient surgery

Subcutaneous RI may not require any adjustment

oral sulfonylureamay be continued until the evening before surgery

delayed hypoglycemia in the absence of any caloric intake

biguanideless risk of hypoglycemia

metformin

risk of lactic acidosis

Poorly controlled IDDM

preoperative admission

Anesthetic Management

Intra-operative

Anesthetic plan depend on the presence of end organ disease


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p p p g

heart diseaseinvasive monitoringrenal diseasefluid management and drug selection

gastroparesisaspiration consideration

Blood glucose levels

preoperative + postoperativeintraoperative

the duration and magnitude of surgery

the stability of the diabetes

Dehidrationmay be presenceosmotic diuresis


Intra-operative


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Glucose administration

avoid an overdose

standard glucose dose for adult:

510 g/hr or 100200 mL of 5% glucose/hr

Positioning of patient

peripheral nerve may already be partly ischemic

susceptible to pressure or scratch injury


Intra-operative

The choice of drugs or techniques for induction or maintenance of anesthesi


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The choice of drugs or techniques for induction or maintenance of anesthesi

less important than monitoring of blood glucose concentration

treatment of potential physiologic derangement

associated with diabetes

GA

tracheal intubation w/ cuffed tube

RA

preserve glucose tolerance

high incidence of peripheral neuropathy

diabetic sensory neuropathy could be erroneously attributed to RA

Management of diabetes

To prevent hypoglycemia


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To prevent hypoglycemia

To accept mild hyperglycemia

can be corrected gradually in the postoperative periode

Monitoring blood glucose concentration

more important than selection of formula5% glucose/IV

Regiments for exogenous insulin replacement

Subcutaneous insulin administration

administer to the usual daily intermediate-acting dose of insulin on the morning of surg


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ad ste to t e usua da y te ed ate act g dose o su o t e o g o su g

initiate infusion of glucose (510 g/hr) with initiation of insulin infusion

Continuous intravenous infusion of insulin

Regular insulin (50 units in 500 mL NS) at 0.51 unit/hr

initiate infusion of glucose (510 g/hr) with initiation insulin infusion

measure blood glucose concentration as necessary (usually every 12 hours)

and adjust insulin infusion accordingly

220 mg/dL increase insulin infusion rate by 0.5 unit/hr

Diabetic Emergencies


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Hyperosmolar non-ketotic comaDiabetic ketoacidosis

Hypoglycemia

Hyperosmolar non-ketotic coma


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Elderly patients with impaired thirst mechanism

Minimal or mild diabetes

Profound hyperglycemia (>1000 mg/dL)

Absence of ketoacidosis, normal arterial pH

Hyperosmolarity (> 330 mOsm/L

seizures, coma, venous thrombosis)Osmotic diuresis (hypokalemia)

Hypovolemia

Seizures and coma (decreased intracellular brain water due to hyperosmolarity)

Diabetic ketoacidosis

Metabolic acidosis


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Hyperglycemia (300500 mg/dL)

Dehydration (osmotic diuresis and vomiting)

Hypokalemia

Skeletal muscle weakness (hypophosphatemia with correction of acidosis)

insufficient insulin to block the metabolism of fatty acids

resulting in the accumulation of acetoacetate and -hydroxybutyrate

Management

Regular insulin U/IV


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followed by a continuous IV infusioninsulin in U/hr = blood glucose/150)

Intravenous fluids (isotonic)

as guided by vital signs and urine output

Potassium Chloride 1040 mEq/hr/IV

when urine output exceeds 0.5 mL/kg/hr

Glucose 5%100 mL/hr, when serum glucose concentration drops below 250 mg/dL

Consider Sodium Bicarbonate IV

to correct pH < 7.1

Hypoglycemia

If renal disease prolongs the action of insulin or oral hypoglycemic agents

Avoidable !


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Produces signs of SNS stimulation

tachycardia

hypertensiondiaphoresis

in anesthetized patient may be:

masked

misdiagnosed

as an inadequate level of anesthesia relative to surgical stimula

Thyroid Gland

Thyroid metabolism and function


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Thyroxine (T4) and Tri-iodothyroxine (T3)

major regulator of cellular metabolic activity

Thyroid gland is solely responsible for the dayly secretion of T480% of T3is produced by extrathyroidal deiodination of T4

mediated most of the excess effects of thyroid hormones (hyperadrenergic stat

Effect of T3on receptor concentration:

number of receptors

number of cardiac cholinergic receptors

Tests for the diagnosis of thyroid gland dysfunction


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T4 T3 TSH

Hyperthyroidism Normal

Primary hypothyroidism

Secondary hypothyroidism

Hyperthyroidism

A hypermetabolic statenervousness

heat intolerance

muscle weakness


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tremorsweight loss

cardiovascular signs

arrhythmias (ST, AF)

systolic murmurs

high output

CHF

Etiologies:Graves disease

Toxic multinodular goiter

Subacute thyroiditis

Toxic adenoma

Ovarian tumor secreting thyroid hormone (struma ovarii)

TSH or -HCG overproduction

Hyperthyroidism

Anesthetic consideration:


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Preparation

proppylthiouracil

inhibit synthesis and peripheral conversion of T4to T3inorganic iodine

inhibits hormone release

-adrenergic antagonistsHR to < 90 beats/min

glucocorticoids

hormone release and peripheral conversion of T4to T3

Intraoperative management

Goal:

to achieve a depth of anesthesia that prevents an exaggerated SNS respo

to surgical stimulation

avoid administration of drugs that stimulate SNS


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g

GA

Thiopental

thiourea structureantithyroid activity

Ketamine can stimulate SNS

N2O not reliably suppressing SNS activity

Inhaled anestheticdo not

MACCO accelerates uptake of inhaled anesthetic

need to increase the inspire concentration

to achieve brain partial pressure euthyroid patie

temp.MAC

muscle relaxantdrug that lack of cardiovascular effect

co-existing muscle weaknessinitial dose, close monit RA

epinephrine should not be added to the local anesthetic solution

Monitoring

Early recognition of activity of the thyroid glands


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suggests the onset of thyroid storm

temperature

ECG

Exophthalmuscorneal ulceration

drying

eye protection


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Hypothyroidism

Lethargy


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Intolerance to coldFacial edema with an enlarged tongue

Bradycardia, diminished barereceptor reflexes

Reversible cardiomyopathy

Decreased cardiac output

Pericardial effusion, ascites

Peripheral vasoconstriction

Constipation and an adynamic ileus with delay gastric emptying

Atrophy of adrenal cortex

dilutional hyponatremia, decreased water excretion

Hypothyroidism

Myxedema coma


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Profound hypothyroidism

decrease mental status associated with hyporesponsiveness to CO2

congestive heart failure

hypothermia

exaggerated symptoms of hypothyroidism

decompensated statesurgery

drugs

trauma

infections

Anesthetic consideration

Elective surgery should be postponed in severe hypothyroidism


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Preoperative sedative should be administered with caution

Cortisol supplementation may be necessary

Hypovolemia may be present

Anemia should be corrected

Airway and respiratory difficulties may be due:enlarged tongue

relaxed oropharyngeal tissue

CO2insensitivity

poor gastric emptying

increased sensitivity to all depressant medications

Complications following thyroid surgery

Thyroid storm

A state of physiologic decompensation in severe thyrotoxicosis

surgical stress618 hr postoperatively

diarrhea

vomiting


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hyperpyrexia (3841OC)

hypovolemia, irritable, delirium or coma

DD/ : malignant hyperthermia

pheochromocytoma

inadequate anesthesia

sepsishemorrhage or transfusion/drug reaction

Airway obstruction

CT of the neck

Reccurent laryngeal nerve damage

unilateralhoarseness

bilateral

aphoniaHypoparathyroidism

develop in 2448 hr, include laryngospasm


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INITIAL ASSESSMENT

Primary survey

ABC sequences suggested for CPR

S d


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Secondary surveyA more comprehensive survey follows the primary surveys

PRIMARY SURVEY

A = Airway

ass med all m ltiple tra ma patients ha e


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assumed all multiple trauma patients havea cervical spine injuryinitial stabilization before airway manipulati

manual or sand bags or collar

neutral position

a full stomach

hypovolemic

remove all secretions, blood, vomitus and any existing foreign bodies

If the airway is patent and ventilation is adequate

supplemental O2monitor closely

initiate other resuscitative measures

Endotracheal intubation

Awake patient

nature of injury

ability to cooperate

general stability


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general stabilityawake nasal or orotracheal intubation

blind nasal intubation

rapid sequence intubation

awake tracheostomy

Combative patient

hypoxemia must always be excluded

rapid sequence induction and orotracheal intubation

Unconscous patient

orotracheal intubation

Intubated patient

verify the position of the endotracheal tube

B = Breathing

Most critically ill trauma patients require assistedif not controlledventilation

bag-valve device

immediately after intubation

during period of transport


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during period of transportdeliver 100% O2 until oxygenation is assessed by ABG

Patient with head trauma

hyperventilation

ICP

Ventilation may be compromised by

pneumothorax

flail chest

ET obstruction

direct pulmonary injury

C =C

irculation

Hemodynamic

initially assessed by palpating pulses

Intravenous access


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Intravenous accessat least 2 large (min: 16-G) catheters are required

injury of the abdomen (and with potential for major venous disruption)

above the level of diaphragm

obstruction or disruption of the superior vena cava is suspected

below the level of the diaphragm

Peripheral venous cannulation failurepercutaneous

subclavian or femoral vein

internal or external jugular vein

surgical cutdowns

saphenous vein at the ankle or thigh

intraosseous infusion

pediatric patients

Volume resuscitation

rapid infusion of warmed crystalloids

colloids?

transfusion of type-specific blood

non-cross-matched blood


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non-cross-matched blooduniversal donor : type-O-non-cross-matched PRC

Vasopressor infusions

should not substitute for adequate volume replacement

as temporary measure

if perfusion pressure is clearly inadequate during ongoing volume resuscitatio

History

Patient, family members, and prehospital care personel

Abbreviated history

Fasting

Mechanism of injury


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Mechanism of injury

blunt trauma

widespread energy transfer to the body

multiple injury in various anatomic locations

penetrating trauma

injury confined to the penetration tracthigh velocity gunshot wounds

tissue disruption in area adjacent to the penetration track

Physical Examination

Frequent monitoring of vital signs

mandatory


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mandatoryprovides an ongoing assessment

airway, neurologic, cardiovascular and pulmonary stability

Assess obvious sites of hemorrhage as well as less obvious sites

Investigate neurologic deficits and vascular compromise

Diagnostic Studies

Laboratory studies

blood type and cross-matching

CBC, platelet count

PT, APTT

Electrolytes


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Electrolytes

glucose

BUN, Creatinine

Urinalysis

Radiographic studies

lateral cervical spine, must include C7T1 interface

sufficient quality to delineate the structures of interest (soft tissue and bones)

CXR

minimum for penetrating injury of the trunk

Pelvis, AP view

12-lead ECG

on all major trauma patients

to evaluate the presence of myocard injury

contusion, tamponade, ischemia and arrhythmias

Monitoring

Dictated by :

severity of the injuries

pre-existing medical problems


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pre existing medical problems

Arterial line

hemodynamic instability

respiratory failure

Central venous pressure line

to assess volume statusto administer vasoactive drugs


ventricular dysfunction

severe coronary artery disease

valvular heart disease

multiple organ system involvement


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INAPPROPRIATE FOR OUTPATIENT SURGERY

Pediatricformerly premature infants < 46 wks post-conceptual age

risk of post anesthesia apnea

infants with respiratory disease

infants with cardiovascular disease


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infants with cardiovascular disease

children with fever, cough, sore throat, coryza or other signs of recent

onset or worsening upper respiratory infection

Adult

Expected to have major blood loss or undergoing major surgeryASA III and IV who require complex or extended monitoring or

postoperative treatment

Morbidly obe patients with significant respiratory disease

Need a complex pain management

Significant fever, wheezing, nasal congestion, cough or other symptoma recent upper respiratory infection

PATIENT PREPARATION

Preoperative testing

MinimalCBC t ti t 50


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aCBC starting at age 50 yrs

ECG starting at age 40

Creatinine & BUN starting at 65 yrs

others performed as indicated

Pre-hospital instructions

diet guidelines

medications

preanesthetic visit

healthy patientsimmediately prior to the planned procedure

Premedication

Anxiolytics

Psychological reassuranceif


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y gif necessary Midazolam 12 mg/IV

Aspiration prophylaxis

Non particulate antacids Na citrate 30 mL just before the procedure

H2-receptor antagonist Ranitidine 150 mg PO the night before surgery

Metoclopramide 10 mg PO or IV prior to surgery

Opioids

Fentanyl 50100 g IV may be given

if preoperative pain is present


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GENERAL ANESTHESIA

Induction

Propofol

short duration

depression of pharyngeal reflex

reduced incidence of postoperative emesisSevoflurane


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Sevoflurane

Airway management

Face mask, LMA or tracheal intubation

Muscle Relaxant

Succinylcholine or Mivacurium

Maintenance

Volatile anesthetic

sevoflurane with or without N2O

Propofol

Alfentanil or Remifentanil

supplemental local anesthesia

N2O

REGIONAL ANESTHESIA

Ideal agents

Rapid onset

to minimize case delay


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Short duration

to facilitate quick recovery and discharge

Patient selectionthe benefits of RA will be negated if heavy sedation is required

Separate areas for RAdecrease time in the OR waiting for onset of anesthesia

should be fully equipped with the usual monitoring and resuscitative device

Monitored anesthesia care

For some patient with complex medical problems

Operation would be done under local anesthesia

to monitor the patientto provide medications


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to provide medications

sedatives or opioids

POSTOPERATIVE CAREPACU

awake, oriented, stable VS, - PONV, minimal pain/discomfort,

able to sit without assisstance

phase II

fast trackPain


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Pain

pain on admission to PACUIV

awake, no painPO

Nausea and vomiting (PONV)

predisposing factors

history of PONV

history of severe motion sickness

use of large doses of opioids

pelvic procedures in female

gastric distentionsevere postoperative pain


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Anesthesia for High Risk Patients

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