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Pulmonary hypertension and anesthesia

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PULMONARY HYPERTENSION & ANESTHESIA Dr. wesam farid Mousa Dr. Salwa hassan khalil Anesthesia & Surgical ICU Department Faculty of Medicine Tanta University
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Pulmonary Hypertension

Pulmonary Hypertension & AnesthesiaDr. wesam farid MousaDr. Salwa hassan khalil

Anesthesia & Surgical ICU DepartmentFaculty of MedicineTanta University

Definition.Classification.Pathogenesis.Diagnosis and treatment of PH.Peri-operative management of PH crisis.PH in special situations..

objectives

Pulmonary circulation is a high flow, low resistance circuit capable of accommodating the entire right ventricular output at one-fifth the pressure of the systemic circulation.

DEFINITION

PH is defined as a mean pulmonary artery pressure greater than 25 mmHg at rest based upon right heart catheterization measurements . A mean pulmonary artery pressure of 8 to 20 mmHg at rest is considered normal,.

RV enlargement secondary to any underlying cardiac or pulmonary disease.

Pulmonary hypertension is the most common cause of cor pulmonale.

Cor pulmonale

An estimated 15 to 52 people in 1 million have PAH world wide.

Armin Sablotzki1, Hans-Juergen SeyfarthJochen Gille1, Stefan Gerlach1, Michael Malcharek1 and Elke Czeslick.Critical Care and Pain Medicine, Klinikum St. Georg gGmbH,Germany Department of Pneumology, Universittsklinikum Leipzig AR, Germany Clinic for Anesthesiology and Critical Care Medicine, Martin-Luther-University of Halle-Wittenberg, Germany2015

Epidemiology

Classification

A distinction between pre-capillary and post capillary PH is fundamental to understand the vascular and hemodynamic changes present in patients with PH.

VC

RARVPAPVPCLALVAo

Post-Capillary PH (PCWP>15 mmHg; PVR nl) Systemic HTNAoV DiseaseMyocardial DiseaseDCM,HCM,ischemic CMRCM,Obesity , othersAtrial MyxomaCor TriatriatumPV compression PVOD

PAHRespiratoryDiseasesPE

Pulmonary Hypertension: Define Lesion

MV Disease

LVEDP

Pre-capillary PHPCWP 3 Wu

CLASIFICATIONMean PAP (mmHg)25 - 4041 - 55>55Degree of diseaseMildModerateSevere

NORMALREVERSIBLE DISEASEIRREVERSIBLE DISEASEPathogenesis of Pulmonary ArterialHypertension

Diagnosis of PHSymptoms of PH

Dyspnea 60%Fatigue19%Near syncope/syncope 13%Chest pain7%Palpitations5%Leg edema3%

Physical ExaminationLoud pulmonary component of the 2nd heart sound P2 (increases PAP)Left parasternal lift (RV heave=R sided overload)Systolic ejection murmur of TR S3 gallop (advanced RV failure)Signs of RV failure:Jugular venous distentionHepatomegalyPerepheral edemaCLEAR LUNGS

Investigations:Right heart catheterization is the gold standard to confirm the diagnosis and establish the severity of PH.

Transthoracic echocardiogram (TTE) remains the method of choice for screening and assessing the PH when clinically suspected.

Once the diagnosis is confirmed, other diagnostic tools assist in establishing the underlying etiology and clinical group to which the patient belongs.

Diagnosis Associated condition

Echocardiography Left ventricular systolic and diastolic dysfunction Left-sided valvular heart disease CHD with systemic to pulmonary shunt

X-ray chest, PFT COPD, sarcoidosis Interstitial pulmonary fibrosis V/Q scan, CTPA Chronic thromboembolic pulmonary disease Sleep study Obstructive sleep apnoeaSerological test(ANA, HIV) Lupus, scleroderma, HIVLiver ultrasound Portopulmonary hypertensionRight heart Catheterisation CHD with systemic to pulmonary shunt Postcapillary PH due to left heart disease Cardiac MRI CHD, cardiomyopathiesOver night Oxymetry PH with OSAH

Algorithm for investigation of suspected PH

Treatment of PHGoals of Therapy

Alleviate symptoms, improve exercise capacity and quality of life

Improve cardiopulmonary hemodynamics and prevent right heart failure

Delay time to clinical worsening

morbidity and mortality

Teraputic TARGETS FOR PH

Anesthetic Management of ph.

PH is a serious condition.perioperative mortality of 7-24%.

Peri-operative morbidity 1442% includes:Respiratory failure Heart failure, dysrhythmiasSepsis, Renal insufficiency, Myocardial infarction.

pre-operative evaluation:

Multidisciplinary team anesthetists, surgeons, pulmonologists, and cardiologists.

Patients suspected of having PH and ungraded severity are at higher risk of peri-operative complications.

Elective surgery must be postponed till a proper pre-op evaluation & optimization.

pre-operative evaluation:

Patient with established PH should be based on a risk assessment :

functional stateseverity of the disease type of surgery.

WHO classification of functional status of patient with PH

Signs of Disease Severity Dyspnea at rest ( WHO- FC class 4)

Low cardiac output with metabolic acidosis

Hypoxemia

Signs of right heart failure

Syncope (poor prognosis)

Chest pain (secondary to RV ischemia)

Rapid progression of symptoms

6 minute walking test 7.4) Recruitment-manoeuver to avoid ventilation/perfusion-mismatch. Low-tidal-volume ventilation to avoid over-inflation of aveoli (goal: 6 ml/kg ideal body weight) Temperature management to maintain body temperature of 36-37 C Goal-directed fluid- and volume-therapy with hemodynamic monitoring

Intraoperative managementOptimize RV function and CO with adequate preload, SVR, and avoid contractility, avoid myocardial depressants

Consider pulmonary vasodilators to decrease RV afterload

Maintain sinus rhythm.

It is good practice to remove air from intravenous syringesand lines

MONITORINGThere is no strong evidence to suggest that any specific type of monitoring has an influence on patient morbidity and mortality. The standard monitoring is considered sufficient for minor & medium procedures in functional state 2.

All major interventions and those in functional state III should be carried out under extended monitoring.

Transesophageal echocardiography (TOE). pulmonary artery catheter.

MONITORINGInvasive arterial monitoring before anesthetic inductionEarly recognition of hemodynamic instability.Intermittent arterial blood gas sampling to check adequacy of ventilation.

Right atrial pressure measurement (central venous pressure)reflects the relationship of blood volume to the capacity of the venous system and also reflects the functional capacity of the right ventricle.

anesthetic techniquesAll standard anesthetic techniques can, in principle applied to patients with PH

anesthetic techniquesRegional anesthetic techniques: Not impairing spontaneous breathingpostoperative analgesic therapy

Nearly all patients with pulmonary hypertension receive continuous anticoagulant therapy; this fact must be taken under.

In severe PH or in diseases affecting the lung, patients cannot be subjected to remaining in a flat position for long period of time.

Regional anesthesia combined with careful GA to ensure adequate oxygenation.

general anesthesiathe main advantages are

Safe oxygenation , uncomplicated airway management, and intraoperative selective pulmonary vasodilation can if necessary easily be administered through the breathing circuit.

general anesthesia

All standard induction anesthetics can be used in combination with opioids, as they have no influence on pulmonary vascular resistance and oxygenation.

Ketamine may PVR due to catecholamine effect. However patients with RV failure may be catecholamine depeleted.

Histamine-releasing muscle relaxants (atracurium , mivacurium) should be avoided for patients with PH, PVR.

general anesthesia

Volatile anesthetic agents of concentrations up to 1 MAC can be administered without any negative effects on pulmonary pressure and resistance.

Nitrous oxide better avoided as it may raise PVR.

So use balanced technique, mixing higher doses of opioids and low-dose volatile anesthetic agents ,careful with stress response during intubation.

During Extubation:Maintaining haemodynamic stability and adequate ventilation can be difficult.

Deep extubationMay decrease SVR, contractilityHypoxia and hypercarbia will increase PVR

Awake extubationCan cause severe pulmonary vasoconstrictionNeed tube tolerance without increased sympathetic tone

Patient may need post-op ventilation with ICU admission

postoperative monitoring until pulmonary pressures and right-sided heart functions have stabilized at the preoperative level.

sufficient analgesic therapy in the form of continuous regional anesthesia to avoids higher doses of opioid-based analgesics.

The specific therapy for PH should be resumed at the preoperative dosage as soon as possible. In the postoperative course, it is also advisable to treat pressure elevations.Postoperative manegment

Peri-operative management of PH Crisis

Pulmonary Hypertension With laparoscopyPneumoperitoneum with CO2 causes an increase in end tidal carbon dioxide. Acidosis, arrhythmias ,decrease preload PH crisis.

post operative benefits of laparoscopic surgery must be balanced with intraoperative risk involved.

IAP to be maintained at 10-12 mm of Hg.

CO2 insufflation slow rate to attenuate abdominal stretch response Temporarily deflate the abdomen if necessary.

Combined general with epidural anaesthesia decreasing intraoperative anaesthetic requirement.post operative pain relief.

Pulmonary Hypertension With PregnancyMortality rate of 30% in patients with idiopathic PAH and 56% in patients with PH associated with other conditions.

GA associated with a four-fold increase in maternal mortality

Physiological increase in blood volume causes volume overload in the right heart may cause:thromboembolic events. cerebrovascular accidents.

General principals for high risk parturient.

Left lat. Position .

Fetal monitoring as IUGR due to hypoxemia and increased Hct level.

Anticoagulation is usually recommended. LMWH.

Warfarin and Endothelin receptor antagonists are avoided due to potential teratogenicity.

Elective CS before 32 Ws allows for better planning, a multidisciplinary team.

Oxytocine use low dose (10 units IV inf) slowly over 4-8 hr.

Methergine absolute CI

SUMMARY

summary


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