1. PRE-OPERATIVE PULMONARY RISK STRATIFICATION
URVASHI VAID MD,MS
AUG 2012
PRE-OPERATIVE PULMONARY RISK STRATIFICATION

2. OUTLINE Why do we care? At risk population Tools for assessment
Prevention of Post-op complications
Risk Indices
Clinical scenarios
Thoracic Surgery and Lung cancer
Bariatric Surgery
Cardiac Surgery

3. WHY DO WE CARE? What are PPC?
VC reduced by 50-60% after thoracic/upper abdominal Sx- remains or a week, FRC reduced by 30%
As prevalent as cardiac complications
Morbidity
Length of stay
Mortality
Prevalence 6.8% across all surgeries
Pneumonia, Atelectasis, Respiratory failure, exacerbation of underlying chronic lung disease, Infection, Bronchospasm
One broad definition of postoperative pulmonary complications includes all patients with fever and either pulmonary signs, symptoms (eg, productive cough, rhonchi, or diminished breath sounds), or changes on chest x-ray (eg, atelectasis, consolidation, or incomplete expansion) [3,4]. However, many such liberally defined postoperative complications are of no clinical relevance.
Another proposed definition is a pulmonary abnormality that produces identifiable disease or dysfunction that is clinically significant and adversely affects the clinical course [5]. This would include several major categories of clinically significant complications, including [6,7]:
■Atelectasis
■Infection, including bronchitis and pneumonia
■Prolonged mechanical ventilation and respiratory failure
■Exacerbation of underlying chronic lung disease
■Bronchospasm
The rate of postoperative pulmonary complications across all types of surgery was 6.8 percent in a systematic review of studies that provided explicit outcome definitions [8].
PERIOPERATIVE PULMONARY PHYSIOLOGY — Postoperative pulmonary complications follow logically as an extension of normal perioperative pulmonary physiology. Reduced lung volume after surgery is a major factor contributing to the development of postoperative pulmonary complications.
Thoracic and upper-abdominal surgery are associated with a reduction in lung volumes in a restrictive pattern as follows [9,10]:
■Vital capacity (VC) is reduced by 50 to 60 percent and may remain decreased for up to one week.
■Functional residual capacity (FRC) is reduced by about 30 percent.
Diaphragmatic dysfunction appears to play the most important role in these changes; postoperative pain and splinting are also factors [11]. Reduction of the FRC below closing volumes contributes to the risk of atelectasis, pneumonia, and ventilation/perfusion (V/Q) mismatching. Microatelectasis results in areas of the lung that are perfused but not ventilated, leading to impaired gas exchange with consequent postoperative hypoxemia [12].
A decrease in tidal volume, loss of sighing breaths, and increase in respiratory rate occur after abdominal and thoracic surgery and contribute to the risk of complications. In addition, residual effects of anesthesia itself and postoperative opioids both depress the respiratory drive. Inhibition of cough and impairment of mucociliary clearance of respiratory secretions are factors that contribute to the risk of postoperative infection

4. Why Do We Care?
In most cases of operable lung cancer, a substantial part of functional lung tissue has to be resected which leads to a permanent loss of pulmonary function
An estimated 90% of all patients with lung cancer have underlying COPD and cardiovascular disorders in varying degrees caused by the shared risk factor from tobacco smoking thus at higher risk of intraoperative and postoperative complications
Resection in patients with insufficient pulmonary reserves can result in permanent respiratory disability
The assumption that there is a level of respiratory impairment beyond which resection bears a high risk and is prohibitive drives the ongoing search for the ideal test to predict postoperative lung function and identify the patients at high risk
Clin Chest Med 32 (2011) 773–782

5. SHOW OF HANDS….
Which of the following is not a significant risk factor for PPC in non-cardiothoracic surgery?
Age>60
ASA class II or greater
COPD
Functionally dependant
Mild to moderate Asthma
CHF
Obesity

6. SHOW OF HANDS….
Which of the following is not a significant risk factor for PPC in non-cardiothoracic surgery?
Age>60 OR 2.0
ASA class II or greater OR 4.87
COPD OR 1.79
Functionally dependant OR 2.51
Mild to moderate Asthma
CHF OR 2.93
Obesity

7. ASA CLASSIFICATION

8. AT RISK POPULATION
Malnutrition (albumin <3g/dL) reduces ventilatory drive to hypoxia and hypercapnia, contributes to respiratory muscle dysfunction, alters lung elasticity, and impairs immunity but nutritional intervention before surgery has not been shown to attenuate the risk
Renal impairment (blood urea >30 mg/dl) carries an OR of 2.3 for PPC
Obstructive sleep apnea –early hypoxemia and unplanned reintubation. 9/172 patients had PPC esp if ODI4% >15. Screening-
Pulmonary HTN-
???
Smetana GW. Preoperative pulmonary evaluation. N Engl J Med 1999;340(12):937–44.
Smetana GW, Lawrence VA, Cornell JE. Preoperative pulmonary risk stratification for noncardiothoracic surgery: systematic review for the American College of Physicians. Ann Intern Med 2006;144(8):581–95
Association of sleep-disordered breathing with postoperative complications.AUHwang D, Shakir N, Limann B, Sison C, Kalra S, Shulman L, Souza Ade C, Greenberg HSOChest. 2008;133(5):1128
Well-controlled asthma is not associated with postoperative complications, and neither is a short course of oral corticosteroids

9. AT RISK POPULATION Age (more comorbidities) COPD- RR of 4.7
The OR for in patients ASA class III or higher is 2.6 compared with patients with ASA class I and II
Malnutrition (albumin <3g/dL) reduces ventilatory drive to hypoxia and hypercapnia, contributes to respiratory muscle dysfunction, alters lung elasticity, and impairs immunity but nutritional intervention before surgery has not been shown to attenuate the risk
Smetana GW. Preoperative pulmonary evaluation. N Engl J Med 1999;340(12):937–44.
Smetana GW, Lawrence VA, Cornell JE. Preoperative pulmonary risk stratification for noncardiothoracic surgery: systematic review for the American College of Physicians. Ann Intern Med 2006;144(8):581–95
Well-controlled asthma is not associated with postoperative complications, and neither is a short course of oral corticosteroids

10. SMOKING- To stop or not to stop (And when to stop…)
Cigarette smoking increases the risk of PPC irrespective of the presence of COPD
A significant reduction of this risk is only noted after 8 weeks of cessation
Recent meta-analyses confirm that smoking cessation before surgery does not increase the risk for PPC
The data indicate that stopping smoking before surgery might lower the risk of complications, with a growing effect with longer duration of smoking cessation
Mills E, Eyawo O, Lockhart I, et al. Smoking cessation reduces postoperative complications: a systematic review and meta-analysis. Am J Med 2011;124(2):144.e8–54.e8.
Myers K, Hajek P, Hinds C, et al. Stopping smoking shortly before surgery and postoperative complications: a systematic review and meta-analysis. Arch Intern Med 2011;171(11):983–9.
Smokers: Longer hospital stays, higher risk of readmission, are more likely to be admitted to an intensive care unit, and have an increased risk of in-hospital mortality
Rationale for 8 weeks: losing the cough-promoting effect of cigarettes before any improvement in sputum clearance might predispose to retention of secretions and
postoperative pulmonary complications.

14. PROCEDURE RELATED RISK FOR PPC
Surgical Site- thoracic, AA, abdominal, neurosurgery, head and neck and vascular
Duration of surgery- >3-4 hours
Anesthetic technique- GA
Emergency surgery

15. TOOLS FOR ASSESSMENT History Physical Stair Climbing 6 minute walk ABG
PFTs
CPET
Quantitative V/Q scan

16. HISTORY AND PHYSICAL EXAM
Prior surgeries/anesthesia
Signs of cor pulmonale
Laryngeal height in COPD <4cm has OR 2.0 for PPC*
*McAlister FA, et al. Am J Resp Crit Care Med 2003; 167:741
Upper border of thyroid cartilage to sternal notch.

17. FUNCTIONAL ASSESSMENT
Stair Climbing- height of 20 meters or rate of ascent 15m/min (=VO2 max of 20ml/kg/min) and 12m/min (= VO2 max of 15ml/kg/min)
Brunelli study-5 year survival (97 vs 74; 77% vs 54%, p < 0.001)
Stair climb > 44 steps (Holden, Chest, 1992)
6 minute walk- >400m
ABG ?? PaCO2 >45mmHg
Brunelli A, Pompili C, Salati M. Low-technology exercise test in the preoperative evaluation of lung resection candidates. Monaldi Arch Chest Dis 2010; 73:72–78
Brunelli et al. Performance at Preoperative Stair-Climbing Test Is Associated With Prognosis After Pulmonary Resection in Stage I Non-Small Cell Lung Cancer Ann Thorac Surg 2012;93:1796–801
Kasymjanova G, Correa JA, Kreisman H, et al. Prognostic value of the six-minute walk in advanced non-small cell lung cancer. J Thorac Oncol 2009;4:602–7.
A total of 296 consecutive patients undergoing pulmonary lobectomy and systematic lymph node dissection [13] for pathologic stage I (pT1
or pT2-N0 only) NSCLC and with complete follow-up were analyzed (2000 to 2008). Patients who received induction chemotherapy were excluded. No patients in this series underwent adjuvant chemotherapy or radiotherapy
The stair-climbing test was usually performed within 1 week of the operation. Our hospital has 16 flights of stairs, each consisting of 11 steps. Each step is meters high. Patients were asked to climb, at a pace of their own choice, the maximum number of steps and to stop only for exhaustion, limiting
dyspnea, leg fatigue, or chest pain. All patients were accompanied by a physician, and the patient’s pulse rate and capillary oxygen saturation were monitored by
means of a portable pulse oximeter with a finger probe. All tests were performed on room air.

18. PFTs and CXR
No role in non-thoracic surgery unless you suspect COPD or asthma
“Recommendation 5: Preoperative spirometry and chest radiography should not be used routinely for predicting risk for postoperative pulmonary complications”

19. PFTS in thoracic surgery
Role of ppoFEV1 and ppoDLCO
preoperative FEV1 X [19 - patent segments to be removed/19]
Group A, patients with ppoFEV1 and ppoDLCO > 40% predicted, and group B, patients with either ppoFEV1 or ppoDLCO < 40% predicted or both between 30 and 40% predicted and ppoVO2 peak > 10 ml/kg per min
Found a similar complication rate among the two groups, but a higher 30-day mortality (1.9 vs. 13.5%) in group B.
Puente-Maestu´ L, Villar F, Gonza´ lez-Casurra´n G, et al. Early and long-term validation of an algorithm assessing fitness for surgery in patients with postoperative FEV1 and diffusing capacity of the lung for carbon monoxide <40%. Chest 2011; 139:1430–1438.
Varela et al. [10] demonstrated that ppoFEV1 was rather imprecise in predicting the FEV1 immediately after surgery. In fact, ppoFEV1 was much
higher than the actual FEV1 measured on the first postoperative days, a period when most of the complications occur
Brunelli et al. [8] showed that the ppoFEV1 is unable to predict postsurgical cardiopulmonary complications in lung cancer patients with
moderate to severe chronic obstructive pulmonary disease (COPD), representing a large portion of patients undergoing pulmonary resection. Moreover
the same authors demonstrated that, 3 months following lobectomy, the actual to predicted postoperative ratios of FEV1 and DLCO in COPD patients
were 115 and 122%, respectively

20. CPET

21. CPET For thoracic surgery
VO2max >75% or >20ml/kg/min for pneumonectomy
VO2 max >15ml/kg/min for lobectomy
No surgery if <35% or <10ml/kg/min

22. QUANTITATIVE V/Q SCAN or ct scan
Total and (-500 to -910) Regional functional lung volume
Segments generated by
hounsfield units.
ppo-FEV1 = preoperative
FEV1 X (1-(RFLV/TFLV)).

23. THORACIC SURGERY ESP LUNG CANCER
ERS/ESTS 2009 guidelines
BTS/SCTS 2012 guidelines
Salati M and Brunelli A. Preoperative assessment of patients for lung cancer surgery. Curr Opin Pulm Med 2012, 18:289–294
Bolliger et al. Functional Evaluation before Lung Resection. Clin Chest Med 32 (2011) 773–782
European Respiratory Society (ERS) and the European Society of Thoracic Surgeons (ESTS), the second was published in 2010 on behalf of
the British Thoracic Society (BTS) and the Society for Cardiothoracic Surgeons (SCTS) of Great Britain and Ireland

24. tenets Operability (Physiologic) Resectability (Anatomic)
Preoperative Evaluation of Patients with Lung Cancer Undergoing Thoracic Surgery Batra, Vikas MD; Kane, Gregory C. MD; Weibel, Sandra MD . Clin Pulm Med 2002;9(1):46–52
lung cancer is one of the main indications for lung resection, despite only 15% to 25% of all lung cancers being operable at the time of presentation.

25. Assessment of cardiopulmonary reserve before lung resection ERS/ESTS
They affirmed that all patients should undergo a detailed cardiac history, physical and electrocardiographic examination in order to be risk stratified according to the Revised Cardiac Risk Index (RCRI) [4] proposed by the American College of Cardiology (ACC) Foundation and the American Heart Association (AHA) [5].
Those patients with an RCRI of 3 or greater should be carefully evaluated with specific cardiac tests in order to identify pathological conditions that can be
treated

26. Risk assessment of post-treatment dyspnea- BTS/SCTS

27. Take home for lung surgery candidates
(1) limited role of traditional spirometry and predicted postoperative FEV1
(2) importance of a systematic measurement of carbon monoxide lung diffusion capacity
(3) global approach in fitness evaluation, by assessing the entire oxygen transport system with CPET

28. Risk indices
Arozullah AM, Daley J, Henderson WG, Khuri SF. Multifactorial risk index for predicting postoperative respiratory failure in men after major noncardiac surgery. The National Veterans Administration Surgical Quality Improvement Program. Ann Surg. 2000;232:
The first model was developed using data from 81,719 noncardiac surgeries at 44 medical centers between 1991 and 1993; it was validated using data from 99,390 noncardiac surgeries at 132 medical centers between 1994 and Minor procedures and major transplantations were excluded. Women were also excluded because they were much younger and healthier than the average male patient.1 Patients were followed for 30 days. The model was designed to predict respiratory failure, defined as mechanical ventilation required for at least 48 hours after surgery or as reintubation after having been extubated postoperatively.

29. Risk indices

30. BARIATRIC SURGERY CHF OR 5.3 (1.2-23) Stroke OR 4.1 (1.4-11)
>32,000 patients
0.6% developed PRF and 0.6% PP
30 day mortality greater if developed either (4.3% versus 0.16% and 13.7% versus 0.10%, P < .0001)
CHF OR 5.3 (1.2-23)
Stroke OR 4.1 (1.4-11)
Dyspnea at rest OR 2.64 (1.1-6)
Age, COPD, smoking, diabetes, anesthesia time, increasing weight, type of surgery
Gupta et al. Predictors of pulmonary complications after bariatric surgery. Surg Obes Relat Dis May 13.

31. CARDIAC SURGERY
>11,000 patients
3 groups- normal or mild (<70%, FEV1 >80%), moderate 50-80%, Severe <50%
Early mortality: 1.4% vs 2.9% vs 5.7% (p<0.001)
Similar trend for post-op complications
Saleh et al. Impact of chronic obstructive pulmonary disease severity on surgical outcomes in patients undergoing non-emergent coronary artery bypass grafting. Eur J Cardiothorac Surg Jul;42(1):
OTHERS: h/o CABG, emergent surgery, infiltrate on CXR, BUN>30, acute MI on admission

32. PREVENTION OF POST-OP COMPLICATIONS
Lung Specific Strategies
Anesthetic techniques
Surgical techniques
Peri-operative care

33. PREVENTION OF POST-OP COMPLICATIONS
Lung Specific Strategies Smoking Cessation Lung Expansion Optimize bronchodilators
Anesthetic techniques
Surgical techniques
Peri-operative care
Lung expansion techniques include incentive spirometry; chest physical therapy, including deep breathing exercises; cough; postural drainage; percussion and vibration; suctioning and ambulation; intermittent positive-pressure breathing; and continuous positive-airway pressure.
The available evidence suggests that for patients undergoing abdominal surgery, any type of lung expansion intervention is better than no prophylaxis at all.

34. Lung expansion 172 patients- Celli, B and Snider GL. ARRD 1984
Prospective, RCT in Abdominal surgery
Cochrane review 2009: “We found no evidence regarding the effectiveness of the use of incentive spirometry for prevention of postoperative pulmonary complications in upper abdominal surgery. This review underlines the urgent need to conduct well-designed trials in this field”
For IS: Same applies to CABG (IPPB may work) and esophagectomies too! (Cochrane)
Control=44
IPPB=45
IS=42
DBE=41
PPC
48%
22%
21%
LOS
8.6+-3
9.6+-3
9.9+-6

35. PREVENTION OF POST-OP COMPLICATIONS
Lung Specific Strategies
Anesthetic techniques NM blockade (longer acting worse) Intraoperative PEEP (No effect)
Surgical techniques
Peri-operative care
Cochrane Database Syst Rev Sep 8;(9):CD007922

36. PREVENTION OF POST-OP COMPLICATIONS
Lung Specific Strategies
Anesthetic techniques
Surgical techniques
Peri-operative care
Not enough evidence

37. PREVENTION OF POST-OP COMPLICATIONS
Lung Specific Strategies
Anesthetic techniques
Surgical techniques
Peri-operative care Selective NOT routine use of nasogastric tubes after elective lap lower rates of pneumonia/atelectasis
Don’t forget- early ambulation and DVT prophylaxis

38. THANK YOU!