Preoperative Pulmonary Evaluation: Truth and Fiction Nichole G. Zehnder, MD Instructor in Internal Medicine Division of Hospital Medicine University of Colorado at Denver Hospital Medicine Group What are this patientʼs risks? 72 yo M with history of HTN, hyperlipidemia, COPD, and CAD s/p balloon angioplasty in 1989 presents for right TKA for osteoarthritis. COPD well controlled on no oxygen. Drinks socially and smokes 1 PPD x 50 years. Ortho has asked you to see him to evaluate his preoperative pulmonary risk prior to surgery. Goals for Today Identify impact of postoperative pulmonary complications Recognize clinically important PPCs Identify patient related risk factors Identify procedure related risk factors Understand preoperative clinical evaluation Identify strategies to decrease risk
How Common Are PPCs? Myth: Thromboembolic and cardiovascular complications are more common than post-operative pulmonary complications. Truth: Rates of PPCs are similar to PCCs and more frequent than postoperative thromboembolic events. Clinically Important PPCs Definition varies widely Currently defined as: Pneumonia Respiratory Failure/Prolonged Mechanical Ventilation Bronchospasm Atelectasis Exacerbation of Chronic Lung Disease Complications prolonging hospital stay or contribute to morbidity and mortality Roadmap Clinically Important PPCs Patient Related Risk Factors Procedure Related Risk Factors Preoperative Clinical Evaluation Strategies to Decrease Risk of PPCs
Patient Related Risks Different than patient related cardiovascular preoperative risk factors Smoking Poor general health status Older age Obesity Chronic obstructive lung disease Asthma Smoking Myth: Quitting smoking before surgery reduces rates of PPCs. Truth: Not exactly; risk decreases depending on duration of cessation. Warner et. al. Prospective evaluation of 200 smokers prior to CABG Lower risk of PPCs in those with cessation > 8 wks vs current smokers Cessation < 8 wks had higher rates of PPC than current smokers (57% vs. 14.5%) General Health Status American Society of Anesthesiologists (ASA) classification 2 Some functional limitation due to systemic disease Gerson et al. Pts > 65 yo undergoing abdominal or nonresective thoracic surgery Inability to exercise for 2 min to increase HR to 99 was the strongest predictor of PPCs
Age http://www.elderabusereport.com/images/elderly_hand.jpg Myth: older pts have significantly increase risk for PPCs. Truth: Not exactly. Most studies looking at this did not control for comorbidities but in general, age > 60 yrs is associated with more PPCs. When data is stratefied by ASA class (II-V), periop mortality is the same in all age groups. Obesity Myth: Obesity increases the risk of PPCs. Truth: Obesity is not a significant risk factor for PPCs. Phillips et al. evaluated obese and non-obese patients after lap cholecystectomy and found no difference in PPCs. http://millyonair.files.wordpress.com/2008/09/bathroom_scale.jpg Obstructive Lung Disease Myth: Any obstructive lung disease increases the risk of PPCs. Truth: Pts with COPD have increased risk depending on the type of complication and severity of disease. This is not true for asthma. Risk is greatest for those with symptoms at rest, airflow obstruction on exam, those without optimal exercise capacity.
Roadmap Clinically Important PPCs Patient Related Risk Factors Procedure Related Risk Factors Preoperative Clinical Evaluation Strategies to Decrease Risk Surgical Site Myth: PPCs are patient dependent regardless of surgical site. Truth: Surgical site is the most predictive risk factor for evaluating PPCs. Risk increases as the incision approaches the diaphragm and when surgery lasts longer than 3 hours. Anesthesia Type http://www.usswisconsin.org/pictures/1950%20pic/513%20w.%20lehton en%20operating%20room.jpg Liu and Wu, Anesthesia and Analgesia 2007 Systematic Cochrane and Medline review Postoperative epidural analgesia reduces PPC Neuraxial blockade ı39 Hrisk of pneumonia, ı59 Hrisk of respiratory depression
Roadmap Clinically Important PPCs Patient Related Risk Factors Procedure Related Risk Factors Preoperative Clinical Evaluation Strategies to Decrease Risk Preoperative Studies: CXR Myth: Chest radiograph is of no utility in preoperative evaluation. Truth: Patients 50 yrs undergoing major surgery, those with known cardiopulmonary disease, and those with pulmonary symptoms suggesting underlying undiagnosed disease. Preoperative Studies: PFTs Myth: Every patient needs PFTs prior to surgery with general anesthesia. Truth: Role of PFTs is controversial, general consensus that all candidates undergoing lung resection need them. PFTs selectively: those with tobacco use or shortness of breath undergoing CABG and upper abdominal surgery, those with unexplained SOB or pulm sxs.
Putting it all together Two well validated indices Pneumonia Post-operative respiratory failure Helpful tools to help stratify risk Preoperative Risk Factor Type of surgery Postoperative PNA Point Value Postoperative Resp. Failure Point Value AAA Thoracic Upper Abd Age (yrs) 80 70-79 Functional status Totally dependent Partially dependent COPD Emergency Surgery General Anesthesia Impaired sensorium Current smoker w/in 1 year 15 14 10 17 13 10 6 5 3 4 4 3 27 21 14 6 6 7 7 6 11 -- -- -- Arozullah AM, Daley J, Henderson WG, Khuri SF: Multifactorial risk index for predicting postoperative respiratory failure in men after major noncardiac surgery. Ann Surg 232:242-253, 2000; and Arozullah AM, Khuri SF, Henderson WG, et al: Development and validation of a multifactorial risk index for predicting postoperative pneumonia after major noncardiac surgery. Ann Intern Med 135: 847-857, 2001. Risk Indices for Predicting Postoperative PNA and Respiratory Failure Risk of PNA (Total Point Range) (0-15) 0.24% Risk of Respiratory Failure (Total Point Range) ( 10) 0.5% (16-25) 1.19% (26-40) 4.0% (41-55) 9.4% ( 56) 15.8% (11-19) 2.2% (20-27) 5.0% (28-40) 11.6% (>40) 30.5% Arozullah AM, Daley J, Henderson WG, Khuri SF: Multifactorial risk index for predicting postoperative respiratory failure in men after major noncardiac surgery. Ann Surg 232:242-253, 2000; and Arozullah AM, Khuri SF, Henderson WG, et al: Development and validation of a multifactorial risk index for predicting postoperative pneumonia after major noncardiac surgery. Ann Intern Med 135: 847-857, 2001.
Roadmap Clinically Important PPCs Patient Related Risk Factors Procedure Related Risk Factors Preoperative Clinical Evaluation Strategies to Decrease Risk Decreasing Risk Preoperative Smoking cessation >8 wks prior, treat airflow obstruction in COPD, asthma, begin pt education regarding lung expanding manuevars Intraoperative Neuraxial analgesia, limit surgery to <3 hrs, laproscopic procedures when possible Postoperative Deep breathing exercises and IS, epidural analgesia, intercostal nerve blocks Wrap Up Key Points Identification of PPCs is part of overall preop evaluation PPCs include: PNA, atelectasis, bronchospasm, COPD exacerbation, ARDS, and respiratory failure Most important pt related factors: smoking, COPD, ASA class, poor exercise capacity Most important pt procedure related risk factors: site and type of surgery, type of anethesia/analgesia Two well developed indices to help identify PPC risk Preoperative, intraoperative, postoperative strategies may decrease risk for PPCs
References Lawrence VA, Hilsenbeck SG, Mulrow CD, Dhanda R, Sapp J, Page CP. Incidence and hospital stay for cardiac and pulmonary complications after abdominal surgery. J Gen Intern Med 1995; 10:671-8. Smetana GW. Preoperative pulmonary assessment of the older adult. Clin Geriatr Med 2003; 19:35-55. Pak M and Smetana G. Preoperative Pulmonary Evalution. In: Glasheen JJ, ed. Hospital Medicine Secrets. 1st ed. Philadelphia, PA; 2007:490-4. Warner MA, Offord KP, Warner ME, Lennon RL, Conover MA, Janson-Schumacher U. Role of preoperative cessation of smoking and other factors in postoperative pulmonary complications: a blinded prospective study of coronary arter bypass patients. Mayo Clin Proc 1989; 64:609-16. Gerson MC, Hurst JM, Hertzberg VS, Baughman R, Rouan GW, Ellis K. Prediction of cardiac and pulmonary complications related to elective abdominal and noncardiac thoracic surgery in geriatric patients. Am J Med 1990; 88:101-7. Kroenke K, Lawrence VA, Theroux JF, Tuley MR. Operative risk in patients with severe obstructive pulmonary disease. Arch Intern Med 1992; 152:967-71. Phillips EH, Carroll BJ, Fallas MJ, Pearlstein AR. Comparison of laproscopic cholecystectomy in obese and non-obese patients. Am Surg 1994;60:316-20. Lawrence VA, Page CP, Harris GD. Preoperative spirometry before abdominal operations: a critical appraisal of its predictive value. Arch Intern Med 1989; 149:280-5. Arozullah AM, Khuri SF, Henderson WG, et al: Development and validation of a multifactorial risk index for predicting postoperative pneumonia after major noncardiac surgery. Ann Intern Med 135: 847-857, 2001. Arozullah AM, Daley J, Henderson WG, Khuri SF: Multifactorial risk index for predicting postoperative respiratory failure in men after major noncardiac surgery. Ann Surg 232:242-253, 2000.