Preoperative pulmonary evaluation and management


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This slide presentation covers areas about physiology of respiratory system related to surgery and anaesthesia, definition of postoperative pulmonary complications (PPCs), risk of PPCs, screening for PPC risk and specific management for patients with increased risk.

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Preoperative pulmonary evaluation and management

  1. 1. Preoperative Pulmonary Evaluation and Management S a n t i S i l a i r a t a n a , M D
  2. 2. Related Pulmonary Physiology
  3. 3. Pulmonary Function System Mechanics 1 Nerve impulse from brain 2 Respiratory muscle contraction 3 4 5 Intrathoracic 
 change & 
 Inspiratory flow Respiratory 
 & lung recoils 6 Gas 
 exchange Intrathoracic 
 change & 
 Expiratory flow
  4. 4. Lung Volume Definitions Total lung
 capacity (TLC) Vital
 capacity Tidal
 volume Inspiratory
 capacity Functional
 capacity Inspiratory
 volume Expiratory
  5. 5. Closing Volume The volume in the lungs at which 
 its smallest airways collapse The air remaining in the lung = Residual volume Beyond equal pressure point (EPP) intrapulmonary pressure > intraairway pressure ➡ airway collapse
  6. 6. Changes of FRC and CC: Conditions Decreased FRC Spine position Obesity Pregnancy General anesthesia Abdominal pain/splinting Increased CC Advanced age Smoking COPD Pulmonary edema Goldman DR, Brown FH, Guarnieri DM (eds) Perioperative Medicine. New York, McGraw-Hill, 1994.
  7. 7. Changes in Pulmonary Function with Surgery Diaphragm function Gas exchangeLung volumes Control of breathing Lung defense mechanisms Reduction in lung volumes Diaphragmatic dysfunction Impaired gas exchange Respiratory depression Impaired cough reflex and mucociliary function
  8. 8. Lung Volume Changes 50-60% Reduction of vital capacity 30% Reduction of functional residual capacity for up to
 1 week
  9. 9. Diaphragmatic Function DECREASED sympathetic reflexes vagal reflexes splanchnic receptor responses Diaphragmatic: irritation manipulation splinting immobilization Diaphragmatic
 dysfunction ➡
 Basal lung 
 atelectasis ➡ V/Q mismatching
  10. 10. Gas Exchange Low lung volume ➡
 Decreased FRC ➡ Decreased airway radius ➡ Atelectasis ➡ V/Q mismatching
  11. 11. Control of Breathing Residual effects of preanesthetic or anesthetic agents Depression of hypercapnid/hypoxic ventilatory drive from narcotics Decreased tidal volume Reduced minute ventilation Increased PaCO2 Decreased frequency of sigh breaths Precipitation of sleep apnea
  12. 12. Lung Defense Mechanisms in Perioperative Period coughing Mucociliary clearance Damage of cilia and mucous gland by ET tube and/or inhaled anaesthetics Decreased clearance velocity by ET tube Suppression 
 of cough by opioids Reduced muscle strength due to neuromuscular blocking agents InfectionV/Q mismatchingAtelectasis
  13. 13. Postoperative Pulmonary Complications
  14. 14. Definition of Postoperative Pulmonary Complications 3 Exacerbation of underlying chronic lung disease Infection (Acute tracheobronchitis, pneumonia)2 1 Atelectasis 5 Thromboembolic disease 4 Prolonged mechanical ventilatory support/respiratory failure
  15. 15. Factors Associated with PPCs PPCs Preoperative Post- operative Intra- operative Chronic lung disease (esp. COPD) Upper respiratory 
 tract infection Age Smoking General health status Nutritional status Heart failure pulmonary hypertension Obesity obstructive sleep apnea Type of anaesthesia Duration of anaesthesia Surgical site Type of surgical incision Inadequate pain control Immobilization
  16. 16. Age Age ≥80 70-79 60-69 50-59 Odd Ratio of developing pulmonary complications 0 2 4 6 8 10 1.5 2.28 3.9 5.63 Smetana GW, Lawrence VA, Cornell JE, American College of Chest Physicians. Ann Intern Med 2006; 144: 581. Age >50 years was an important independent factor of risk Preoperative Factors
  17. 17. Smoking Preoperative Factors Relative Risk (RR)
 for postoperative complications ! 1.73 (95% CI 1.35-2.23)
  18. 18. American Society of Anesthesiologist:
 Physical Status Classification Preoperative Factors Class Description ASA 1 A normal healthy patient ASA 2 A patient with mild systemic disease ASA 3 A patient with severe systemic disease ASA 4 A patient with severe systemic disease that is a constant threat to life ASA 5 A moribund patient who is not expect to survive without the operation ASA 6 A declared brain-dead patient whose organs are being removed for donor purposes ASA class >2 confers ! 4.87X increased risk (95% CI 3.34-7.10)
  19. 19. Chronic Obstructive Pulmonary Disease Preoperative Factors Increased 
 production Airway 
 inflammation and edema Loss of 
 radial traction & Elastic recoil Decreased airway radius ! Increased closing volume 6X more likely to have major postoperative 
 pulmonary complications
  20. 20. Asthma Preoperative Factors Patients with asthma who are well controlled and have a peak flow measurement of >80% predicted can proceed to surgery with average risk
  21. 21. Obesity Chest wall recoil ~ Lung elastic recoil
 ➡Outward ~ Inward @balance = FRC Decreased chest wall recoil ➡Outward < Inward @new balance = decreased FRC (ERV) Preoperative Factors
  22. 22. Effects of Obesity on Pulmonary Function Low lung volume ➡
 Decreased FRC ➡ Decreased airway radius ➡ Atelectasis ➡ V/Q mismatching However, obesity has NOT consistently been shown to be a risk factor for PPCs Obesity should NOT affect patient selection for otherwise high-risk procedure Preoperative Factors
  23. 23. Obstructive Sleep Apnea Preoperative Factors Odd Ratio (OR)
 for postoperative respiratory failure 1.95 (95% CI 1.91-1.98) Higher incidence of: Unplanned ICU transfers Longer length of stay Pneumonia Respiratory failure
  24. 24. Heart Failure Pulmonary congestion ➡
 Decreased compliance ➡ Low lung volume ➡ Decreased airway radius ➡ Atelectasis ➡ V/Q mismatching Airway edema Odd Ratio (OR)
 for postoperative complications 2.93 (95% CI 1.02-8.43) Preoperative Factors
  25. 25. Surgical Site Intraoperative Factors Esophagectomy Upper abdominal surgery Lower abdominal surgery Complication rates 18.9% 19.7% 7.7%
  26. 26. Type of Anesthesia Intraoperative Factors General anesthesia leads to a ! HIGHER RISK ! of clinically important pulmonary complications than does epidural or spinal anesthesia Rodgers A, Walker N, Schug S, et al. BMJ 2000; 321: 1493.
  27. 27. Preoperative Evaluation & Risk Assessment
  28. 28. Assessment tools History & PE Chest x-ray Lung function tests Risk Indices Obesity: Body Mass Index (BMI) Mallampati grade Asthma: Level of control ACT, ACQ COPD: CAT, mMRC Exacerbation Spirometry Lung Volume study, DLCO Polysomnography Arozullah 
 respiratory failure 
 index Canet risk index ASA class Gupta 
  29. 29. History & Physical Examination COPD ! CAT score/mMRC History of exacerbation Decreased laryngeal height increased AP diameter Wheezing/rhonchi Obesity/OSA ! Body mass index Mallampati class Epworth Sleepiness Score ! Asthma ! ACT score, Level of control History of exacerbation Wheezing/rhonchi
  30. 30. Chest Radiograph Patient without risk factor Patient with risk factors (cardiac or pulmonary diseases) 0.3% Abnormality detected 22% Abnormality detected Rucker L, Frye EB, Staten MA. JAMA 1983; 40: 1022.
  31. 31. Pulmonary Function Tests Patients with COPD or asthma with uncertain optimal symptom/disease control Patients with unexplained dyspnea or exercise intolerance 2006 American College of Physicians guideline: NOT to be used as the primary factor to deny surgery NOT to be routinely ordered Qaseem A, Snow V, Fitterman N. et al. Ann Intern Med 2006; 144: 575.
  32. 32. Arozullah Respiratory Failure Index Preoparative predictor Point value Abdominal aortic aneurysm 27 Thoracic 21 Neurosurgery, upper abdominal, peripheral vascular 14 Neck 11 Emergency surgery 11 Albumin <3.0 g/dL 9 BUN >30 mg/dL 8 Partially or fully dependent functional status 7 History of chronic obstructive pulmonary disease 6 Age >70 years 6 Age 60-69 years 4 Type of surgery General 
 health status Age
  33. 33. Performance of the Arozullah Respiratory Failure Index Class Point total Percent respiratory failure 1 ≤10 0.5 2 11-19 1.8 3 20-27 4.2 4 28-40 10.1 5 >40 26.6 Arozullah AM, Daley J, Handerson WG, Khuri S. Ann Surg 2000; 232: 242.
  34. 34. Canet Risk Index Factor Adjusted odds ratio Risk score Age ≤50 years 1 0 51-80 1.4 (0.6-3.3) 3 >80 5.1 (1.9-13.3) 16 Preoperative O 1 0 91-95% 2.2 (1.2-4.2) 8 ≤90% 10.7 (4.1-28.1 24 Respiratory infection in the last month 5.5 (2.6-11.5) 17 Preoperative anemia (Hb ≤10 g/dL) 3.0 (1.4-6.5) 11 Canet J, Gallart L, Gomar C, et al. Anesthesiology 2010; 113: 1338.
  35. 35. Canet Risk Index Factor Adjusted odds ratio Risk score Surgical incision in upper abdomen 1 0 >80 5.1 (1.9-13.3) 16 Duration of surgery ≤2 hours 1 0 2-3 hours 2.2 (1.2-4.2) 8 >3 hours 10.7 (4.1-28.1 24 Emergency surgery 5.5 (2.6-11.5) 17 High risk (42.1%) ≥45 points Moderate risk (13.3)%) 26-44 points Low risk (1.6%) <26 points Pulmonary complication rate:
  36. 36. Gupta Calculator for Postoperative Respiratory Failure respirology/postoperative-respiratory- failure-risk-calculator Gupta H, Gupta PK, Fang X, et al. Chest 2011; 140(5): 1207-15.
  37. 37. Perioperative Risk Evaluation: Obstructive Sleep Apnea Factor Points A. Severity of sleep apnea based on sleep study (or clinical indicator) None 0 Mild 1 Moderate 2 Severe 3 B. Invasiveness of surgery and anaesthesia Superficial surgery under local or peripheral nerve block without sedation 0 Superfacial surgery with moderate sedation or general anaesthesia 1 Peripheral surgery with spinal or epidural anaesthesia 1 Peripheral surgery with general anaesthesia 2 Airway surgery with moderate sedation 2 Major surgery, general anaesthesia ! 3 Airway surgery, general anaesthesia 3
  38. 38. Perioperative Risk Evaluation: Obstructive Sleep Apnea Factor Points C. Requirement for postoperative opioids None 0 Low dose oral opioids 1 High-dose oral opioids, parenteral or neuraxial opioids 3 Total score (Score in A plus the greater of the score for either B or C) Gross JB, Bachenberg KL, Benumof JL, et al. Anesthesiology 2006; 104: 1081-93. Significantly increased risk 5-6 points Increased risk 4 points Low risk <4 points
  39. 39. Risk Assessment: Non-resective-lung Surgery History and physical examination Seeking known risk factors for pulmonary complications Low risk: Proceed to surgery without further evaluation Positive Negative Identify risk(s) presents in the patient Chest x-ray* Pulmonary function test* Moderate risk: Perioperative treatment to reduce risk Normal High risk: Reconsider indication for surgery Perioperative treatment to reduce risk Consider shorter procedure Consider epidural/spiral anesthesia Abnormal
  40. 40. Perioperative Management
  41. 41. Stepwise Approach What is/are 
 the risk(s)? Type of: Surgery Incision Anesthesia General perioperative management Specific perioperative management
  42. 42. Strategies to Reduce 
 Postoperative Pulmonary Complications Preoperative measures Smoking cessation Bronchodilators* Systemic corticosteroids* Antibiotics* Inspiratory muscle training Chest physical therapy Patient education Intraoperative measures Spinal/Epidural anesthesia Short-acting neuromuscular blockers Briefer procedure Endoscopic/Laparoscopic procedures Lung protective ventilation Postoperative measures Deep breathing Incentive spirometry CPAP Pain control
  43. 43. Smoking Cessation surgery patients and rapid referral to a smoking- n program could maximize the cessation period be- gery, resulting in greater reductions in postoperative ations in the secondary care setting. 14. Theadom A, Cropley M. Effects of preoperative smoking cessation on the incidence and risk of intraoperative and postoperative complica- tions in adult smokers: a systematic review. Tob Control. 2006;15: 352-358. Figure 3 Meta-regression plot, effect of time of cessation on complications. 153al Smoking Cessation Reduces Perioperative Complications Mills E, Eyawo O, Lockhart I, et al. Am J Med 2011; 124:144. Relative Risk (RR)
 for postoperative complications ! 0.81 (95% CI 0.70-0.93) in former smokers ! 0.59 (95% CI 0.41-0.85) in patients who had ≥4 weeks smoking cessation Even cessation of smoking for 2 days may have some benefits: less carboxyhemoglobin, less effects from nicotine, 
 improved mucociliary clearance
  44. 44. Deep Breathing & Incentive Spirometry Equally effective (deep breathing vs incentive spirometry) 50% reduction of postoperative pulmonary complications Incentive spirometry is recommended after upper abdominal and thoracic surgery
  45. 45. Continuous Positive Airway Pressure Improved oxygenation Reduced incidence of pneumonia, intubation, and admission to an ICU However, CPAP may cause patient discomfort gastric distension barotrauma Zarbock A, Mueller E, Netzer S, et al. Chest 2009; 135: 1252. commended as a secondary intervention for 
 refractory atelectasis ➡
  46. 46. Specific Management: COPD Continue current medications (if stable) Give regular bronchodilator therapy (Ipratropium/Tiotropium) for 24 hr prior to surgery until 24 hr postextubation Give systemic steroid (e.g. dexamethasone 4 mg iv) 1-2 doses 12 hr prior to surgery in severe symptomatic patient or patient with frequent exacerbation Continue systemic steroid for 3-5 days in severe cases (but no more than 7 days)
  47. 47. Specific Management: Asthma For patient with controlled asthma: Continue current asthma medications Apply inhaled rapid-acting beta agonist 2-4 puffs or nebulizer treatment within 30 minutes of intubation Give nebulizer treatment in the perioperative period (~24 h after extubation) For patient with partly or uncontrolled asthma: Systemic glucocorticoid (e.g., dexamethasone 4 mg) 
 1-2 doses in 12 hour prior to surgery may be used Systemic glucocorticoid may be continued for 3-5 days in severe cases
  48. 48. Specific Management: Morbid Obesity Administer induction drugs, opioids, and neuromuscular agents using ideal body weight (IBW) NOT total body weight Positioning in“ramped”and“reversed Trendelenberg”position Awake intubation in patient when mask oxygenation is inadequate Application of 100% oxygen with PEEP 10 cmH2O for 5 minutes before the induction of anesthesia ± PEEP 10 cmH2O thereafter
  49. 49. Preoperative Evaluation for Lung Resection
  50. 50. General Evaluation Steps 1 2 3 4 5 Spirometry DLCO Predicted 
 postoperative FEV1 Predicted 
 postoperative DLCO Simple exercise test Cardiopulmonary exercise test FEV1 2 L for pneumonectomy 
 FEV1 1.5L for lobectomy 
 >80% of Predicted normal DLCO 
 >80% predicted PPO FEV1
 >60% predicted ! PPO DLCO >60% predicted >400 m 
 shuttle walk test ! >22 m stair climbing test Unexplained symptoms? >30% <30% VO2 max 
 >20 mL/kg/min Averaged risk Increased risk High risk