PREANAESTHETIC EVALUATION

PRESENTED BY DR JAYESH

PG STUDENTDEPT OF ORAL AND MAXILLOFACIAL SURGERY

CONTENTS AIM

PURPOSE OF MEETING OF PATIENT AND ANAESTHESIST IMPORTANT FUNCTION OF PREOPERATIVE EVALUATION ARE

General Health Assessment What Are the Different Methods of Surgery

According to ASA Laboratory work up

The normal AND ABNORMAL blood picture INR ,PT, PTT and ISI

Electrolyte and creatinine CVS assesment

Exercise tolerance Chest radiographs Elecro cardiogram

Pulmonary function test Diabetes mellitus

Steroids Management of patient of anticoagulant

Conclusion bibliography

AIM THE ULTIMATE GOAL OF PREOPERATIVE

MEDICAL ASSESMENT OF PATIENTS ARE TO REDUCE THE MORBIDITY OF SURGERY, TO INCREASE QUALITY BUT DECREASE COST OF POST OPERATIVE CARE, AND TO RETURN THE PATIENT TO DESIRABLE FUNCTIONING AS QUICKLY AS POSSIBLE

AS A CONSULTANT, THE QUESTION ASKED IS: “FOR THIS PATIENT, ARE THE MEDICAL CONDITIONS AS GOOD AS THEY CAN BE?”

PURPOSE OF MEETING OF PATIENT AND ANAESTHESIST

PURPOSE 1. Documentation of the condition(s) for which

surgery is needed. 2. Assessment of the patient’s overall health

status. 3. Uncovering of hidden conditions that could

cause problems both during and after surgery. 4. Perioperative risk determination. 5. Optimization of the patient’s medical condition

in order to reduce the patient’s surgical and anesthetic perioperative morbidity or mortality.

6. Development of an appropriate perioperative care Plan.

7. Education of the patient about surgery, anesthesia, intraoperative care and postoperative pain treatments in the hope of reducing anxiety and facilitating

recovery. 8. Reduction of costs, shortening of hospital stay,

reduction of cancellations and increase of patient satisfaction.

IMPORTANT FUNCTION OF PREOPERATIVE EVALUATION ARE

1.OPTIMIZING PATIENT HEALTH BEFORE SURGERY

2.MOST APPROPRIATE PERIOPERATIVE MANAGEMENT

General Health Assessment

The history- include a past and current medical history, a surgical history, a family history, a social history (use of tobacco, alcohol and illegal drugs), a history of allergies current and recent drug therapy, unusual reactions or responses to drugs and any problems or

complications associated with previous anesthetics.

Systemic history-• look for undiagnosed chronic disease• Inadequately controlled chronic disease

What Are the Different Methods of Surgery

Open surgery

Minimally invasive surgery

It can also be classified as1..Class A- minimally invasive-° less potential to disrupt normal physiology. ° Rarely associated with morbidity associated with anesthesia° Rarely require blood administration, invasive monitoring, or postoperative management in intensive care serting

2.. Class B- moderately invasive° modest potential to disrupt normal physiology° may require blood administration° Invasive monitoring or monitoring in intensive care

3.. Class 3 highly invasive – Significant disrutption of normal

physiology Almost always require blood

administration Invasive monitoring or post operative

management in critical care setting

According to ASA

Laboratory work up

Complete blood count:- Red blood cells, which carry oxygen White blood cells, which fight

infection Hemoglobin, the oxygen-carrying

protein in red blood cells Hematocrit, the proportion of red

blood cells to the fluid component, or plasma, in your blood

Platelets, which help with blood clotting

The normal blood picture Red blood cell count Male: 4.32-5.72 trillion cells/L* (4.32-5.72 million cells/mcL**) Female : 3.90-5.03 trillion cells/L (3.90-5.03 million cells/mcL)

Hemoglobin Male: 13.5-17.5 grams/dL*** (135-175 grams/L) Female: 12.0-15.5 grams/dL (120-155 grams/L)

Hematocrit Male: 38.8-50.0 percent Female: 34.9-44.5 percent

White blood cell count

3.5-10.5 billion cells/L (3,500 to 10,500 cells/mcL)

Platelet count

150-450 billion/L (150,000 to 450,000/mcL**)

INR ,PT, PTT and ISI A prothrombin time (PT) is a test used to help

detect and diagnose a bleeding disorder or excessive clotting disorder;

The international normalized ratio (INR) is calculated from a PT result and is used to monitor how well the blood-thinning medication (anticoagulant) warfarin is working to prevent blood clots.

The partial prothrombin time (PTT) test evaluates those protein factors that are part of the intrinsic and common pathways

For calculating the international normalized ratio, a patient's prothrombin time is divided by the mean normal prothrombin time. This ratio is raised to a power called the international sensitivity index

The reference range for prothrombin time is 9.5-13.5 seconds.

The reference range for international normalized ratio (INR) is less than 1.3

However, the normal range is highly variable and dependent on the laboratory performing the test

The prothrombin time is a measure of the integrity of the extrinsic and final common pathways of the coagulation cascade. This consists of tissue factor and factors VII, II (prothrombin), V, X, and fibrinogen. The test is performed by adding calcium and thromboplastin, an activator of the extrinsic pathway, to the blood sample then measuring the time (in seconds) required for fibrin clot formation.

Electrolyte and creatinine

ELECTROLYTES ARE MINERALS IN YOUR BLOOD AND OTHER BODY FLUIDS THAT CARRY AN ELECTRIC CHARGE

COMMON ELECTROLYTES INCLUDE: Chloride: 95-105 mmol/L Creatinine: 0.8-1.3 mg/dL Glucose: 65-110 mg/dL Inorganic phosphorous: 1-1.5 mmol/L Ionized calcium: 1.03-1.23 mmol/L Magnesium: 1.5-2 mEq/L Potassium: 3.5-5 mmol/L Sodium: 135-145 mmol/L Total calcium: 2-2.6 mmol/L Urea: 1.2-3 mmol/L Uric acid: 0.18-0.48 mmol/L

CVS assesment American college of cardiology and american heart association published guidelines

for CVS evaluation for non cardiac surgeries

Exercise tolerance It is usually evaluated by the estimated energy

requirement for various activities and graded in metabolic equivalents (MET) on a scale defined by the Duke Activity Status Index

One MET represents the oxygen consumption of a resting adult (3.5 ml/kg/min).

CVS assesment Includesa. Chest radiographs :-

Elecro cardiogram Electrocardiography (ECG or EKG*) is the process of recording the electrical activity

of the heart over a period of time using electrodes placed on the skin

10 lead

5 lead ecg

3 lead ecg

Pulmonary function test Pulmonary function tests (PFTs) are a group of tests that

measure how well your lungs work. This includes how well you’re able to breathe and how effective your lungs are able to bring oxygen to the rest of your body

interpretations

Postoperative pulmonary complications

Procedure-related risk factors: primarily based on how close the surgery is to the diaphragm (i.e. upper abdominal and thoracic surgery are the highest risk procedures).

Length of surgery (> 3 hours) and general anesthesia (vs. epidural or spinal).

Emergency surgery. Underlying chronic pulmonary disease or symptoms of

respiratory infection. Smoking. Age >60 years. Obesity. Presence of obstructive sleep apnea. Poor exercise tolerance or poor general health status.

Diabetes mellitus it is important to remember that patient is more likely to be harmed by

neglect of the long term complications of diabetes than from the short term control of blood glucose levels

diabetic patient who needs elective surgery should be carefully assessed preoperatively for symptoms and signs of peripheral vascular, cerebrovascular and coronary disease

Adequate control of blood glucose concentration (< 180 mg/dL) must be established preoperatively and maintained until oral feeding is resumed after operation.

Oral hypoglycemic agents are withheld the day of surgery for an agent with a short half-life and up to 48 h preoperatively for a long acting agent such as chlorpropamide.

A combination of glucose and insulin is the most satisfactory method of overcoming the deleterious metabolic consequences of starvation and surgical stress in the diabetic patient. Generally, there is no need for insulin infusion in diabetics who are diet-controlled regardless of type of surgery, or in diabetics who are on oral agents only and are undergoing minor surgeries.

steroids Patients on steroids who present for surgery may be at increased

risk of complications because of

The adrenal suppression

The disease or condition which required them to take steroids

Long-term and other side-effects of steroid therapy

patient.info/doctor/precautions-for-patients-on-steroids-undergoing-surgery

Pre-operative considerations Establish how much steroid has been

taken and for how long. 10 mg/day or more of prednisolone (or

equivalent) is generally taken as the threshold dose for 'steroid cover'.

The risk of adrenal suppression

In normal healthy patients there is a prompt secretion of cortisol with the onset of surgery and secretion remains elevated for several days after surgery. Glucocorticoids are not stored and must be synthesised when required - for example, during and after surgery. This response depends on the hypothalamopituitary axis which may be suppressed or unresponsive to stress when steroids have been taken. Failure of cortisol secretion may result in the circulatory collapse and hypotension characteristic of an hypoadrenal or 'Addisonian' crisis.

Peri-operative considerations

Postoperative considerations

Preoperative assessment This should focus on the history of steroid usage, routine

examination (including blood pressure) and basic investigations including FBC, U&Es, blood glucose and LFTs.

Investigation for adrenal suppression is rarely done. It is possible to assess this with:

1. Serum and urinary cortisol.2. Short synacthen test (SST) - more popular but interpret with care. [5]3. Insulin tolerance test.4. Corticotropin-releasing hormone (CRH) measurement.

Peri-operative management and steroid cover

Patients on corticosteroids at a dose of 10 mg or more of prednisolone Patients who have received corticosteroids 10 mg daily within the three

months preceding surgery. Patients on high-dose inhaled corticosteroids

Minor surgery - 25 mg hydrocortisone at induction Moderate surgery Major surgery

Management of patient of anticoagulant

Major concern is when to perform surgery. Ie without risk of hemorrhage or thromboembolism

1. Most patients can undergo dental extractions, arthrocentesis, biopsies, ophthalmic operations and diagnostic endoscopy without alteration of their regimen.

For other invasive and surgical procedures, oral anticoagulation needs to be withheld and the decision whether to pursue an aggressive strategy of perioperative administration of intravenous (IV) heparin or subcutaneous (SC) low-molecular-weight heparin (LMWH) should be individualized

Management recommendations: 1. If INR pre-op is 2-3, stop oral anticoagulant 4 days prior

to surgery (or longer if INR > 3.0). 2. Measure INR one day prior to surgery: if it is ≥ 1.7, give

1 mg vitamin K SC. 3. If on the day of surgery the INR is 1.3-1.7, administer 1

unit of fresh frozen plasma and administer 2 units if the INR is 1.7-2.0.

4. The following approaches can be used: administer full-dose anticoagulation with IV unfractionated heparin (UFH); administer full-dose anticoagulation with LMWH; or administer prophylactic doses of UFH or LMWH.

2. Invasive surgery is generally safe (from major hemorrhagic complication) when the INR ∼1.5.

3. It takes approximately 4 days for the INR to reach 1.5 once oral anticoagulant is stopped preoperatively.

4. It takes approximately 3 days for the INR to reach 2.0 once oral anticoagulant is restarted postoperatively.

5. If oral anticoagulant is held 4 days pre-op and started immediately post-op, the patient is, in the mean time, without anticoagulation for 2 days

Intubation

conclusion The ultimate goals of preoperative medical assessment are to reduce the

patient’s surgical and anesthetic perioperative morbidity or mortality, and to return him to desirable functioning as quickly as possible. It is imperative to realize that “perioperative” risk is multifactorial and a

function of the preoperative medical condition of the patient, the invasiveness of the surgical procedure and the type of anesthetic

administered

Laboratory investigations should be ordered only when indicated by the patient’s medical status, drug therapy, or the nature of the proposed

procedure and not on a routine basis

Proper consultations with appropriate medical services should be obtained to improve the patient’s health. These consultations should

ideally not be done in a “last second” fashion

bibliographyI. Ronald d miller. Anesthesia. Fifth edition

II. Wylie and churchill-davidson’s Apractice of anesthesia

III. HIPPOKRATIA 2007, 11, 1: 13-21

IV. How to read an electrocardiogram (ECG). Part One: Basic principles of

the ECG. The normal ECG. SSMJ Vol 3 Issue 2 May 2010

V. Precautions for Patients on Steroids Undergoing Surgery

VI. How to Read a Chest X-Ray – A Step by Step Approach . SSMJ Vol 1 Issue

2.

VII. Clinical Guideline for the Perioperative Steroid Replacemen

VIII.Preoperative evaluation of the patient with pulmonary disease. Rev

Bras Anestesiol. 2014;64(1):22---34

IX. Pulmonary Function Tests.Harpreet Ranu, Michael Wilde, Brendan Madden.

Ulster Med J 2011;80(2):84-90