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Principle of thoracic anesthesia with determinants of operability for resection,One lung anesthesiaDr. Rajesh Kumar

University College of Medical Sciences & GTB Hospital, DelhiPreanesthetic assessment

Anesthetic management

Postoperative managementobjectivesFundamentals to anesthetic management of thoracic proceduresLung isolation to facilitate surgical accessManagement of one lung anesthesiaPreoperative evaluation

done in two disjoint phases:

The initial clinical assessmentThe final assessment on the day of admission

Primary function of PACTo identify patients at elevated risk, To stratify perioperative management and focus resources

Feasibility of lung resection in a high risk patientcomplicationincidenceRespiratory(atelectasis, pneumonia,respiratory failure)15-20 %Cardiovascular(arrhythmia and ischemia)10-15%Perioperative complications(overall mortality 3-4%)History

Detailed history regarding the quality of life preoperatively

Respiratory mechanicsAll patients should have a baseline spirometry:

FEV1, FVC, MVV, RV/TLC

FEV1% ( % of predicted volume corrected for age,gender and height).

ppo FEV1 % ( predicted post operative FEV1 ) Calculated as ppoFEV1 % = preop FEV1 % (1-% functional lung tissue removed/100)

ppo FEV1 % > 40% low riskppoFEV1 % 20 ml/kg/min has fewer complication

EXPENSIVEStair climbing tests5 flights of stairs ~ V02 max >20 ml/kg/min2 fight of stairs ~ Vo2 max ~ 12 ml/kg/min -- very high risk(climbing should be at patients own pace without stopping,1 flight of stairs = 20 steps withs each step of 6 inches )Assessment of respiratory functions continues

cardiopulmonary interactions(most important assessment of respiratory function)Six minute walk test(6MWT)< 610 m/ 2000 ft ------ Vo2 max< 15 ml/kg/min ~fall in SpO2 > 4% during exercise( increased morbidity and mortality)ppo V02 max< 10 ml/kg/min is an absolute contraindication mortality rate is approximately 100%V-P scintigraphyShould be considerd for any patient of pneumonenctomy having a preop FEV1 &/or Dlco enflurane > isoflurane

In doses less than or equal to 1 MAC, the modern volatile anesthetics depress HPV minimally

Hence TIVA has no proven benefit against 1 MAC inhalational anesthesia

Choice of AnestheticParameterSuggestedGuidelines/ ExceptionsTidal volume5-6mL/kgMaintain:

Peak airway pressure < 35cm H2O

Plateau airway pressure < 25cm H2O

Positive end-expiratory pressure5cm H2OPatients with COPD: no added PEEPRespiratory rate12 breaths/minMaintain normal Paco2; Pa-ETco2 will usually increase 1-3mmHg during OLVModeVolume or pressure controlledPressure control for patients at risk of lung injury (e.g., bullae, pneumonectomy, post lung transplantation)Suggested ventilatory parameters for OLV Therapies for Desaturation during One-Lung Ventilation

Severe or precipitous desaturation: Resume two-lung ventilation (if possible).

Gradual desaturation:

1. Ensure that delivered Fio2 is 1.0.

2. Check position of double-lumen tube or blocker with fiberoptic bronchoscopy.

3. Ensure that cardiac output is optimal; decrease volatile anesthetics to < 1 MAC.

4. Apply a recruitment maneuver to the ventilated lung (this will transiently make the hypoxemia worse).

5. Apply PEEP 5cm H2O to the ventilated lung (except in patients with emphysema).

6. Apply CPAP 1-2cm H2O to the nonventilated lung (apply a recruitment maneuver to this lung immediately before CPAP).

7. Intermittent reinflation of the nonventilated lung

8. Partial ventilation techniques of the nonventilated lung: a. Oxygen insufflation b. High-frequency ventilation c. Lobar collapse (using a bronchial blocker)

9. Mechanical restriction of the blood flow to the nonventilated lung

Post operative complications

Early major Where

37leading cause of postoperative morbidity and mortality

Acute respiratory failure after lung resection is defined as:

acute onset of hypoxemia (Pao2 < 60mmHg) or hypercapnia (Paco2 > 45mmHg

use of postoperative mechanical ventilation for more than 24 hours

reintubation for controlled ventilation after extubation

incidence of respiratory failure after lung resection is between 2% and 18%Post operative respiratory failureTo minimise pulmonary complications postoperatively Thank you