Noncardiac Perioperative Medicine 101

1. Noncardiac Perioperative Medicine 101 Brian Woods Department of Medicine

2. Overview Preoperative Evaluation Risk Reduction Disease Processess and Organs Pulmonary Renal Hepatic Endocrine Rheumatologic Neuro/Psych Infectious Diseases Heme/Vascular

3. Preoperative History General history Specific perioperative issues Personal and family anesthetic history Sleep apnea Exercise tolerance Recent infections Bleeding diathesis Dentition

4. Preoperative Exam CNS and peripheral nervous evaluation Cardiovascular Orthostasis Heart Arteriovenous system Edema Pulmonary Pattern of breathing Upper airway anatomy and function Mallampati Classification Thyromental distance (<3 fingersbreadth is concerning)

7. Aspiration Risk Factors GI obstruction GERD Diabetes Recent solid food intake Abdominal distension (obesity, ascites) Pregnancy Altered mental status Opioid use Upper GI or nasopharyngeal bleeding Airway trauma Emergency surgery

8. Obesity and Perioperative Risk Higher incidence of DM, HTN, CV disease Mask ventilation and intubation more difficult Decreased FRC Increased O2 consumption / Increased CO2 production Diminished ventilation from central hypoventilation and V/Q mismatch Increased abdominal pressure / Aspiration Altered pharmacokinetics Regional anesthesia more difficult Despite all this, no study has shown obesity to be an independent risk factor for pulmonary complications

9. Fasting If no risk factors for aspiration: No solid food for 6-8 hours Oral preop medications can be taken 1-2 hours prior to anesthesia with sips of water Modify fasting regimen according to patient's needs and safety

10. What conditions often change the anesthetic plan? One study discovered that 20% of anesthetic care plans were altered by the preop evaluation Most common causes of change GERD Type 1 DM Asthma Difficult airway

11. Preoperative Studies Testing should be based on the H&P Inappropriate or unneeded tests are costly to the patient, the healthcare system, and society, not only in monetary terms Perioperative behavioral interventions (smoking cessation, weight loss) may be more beneficial than any lab test

12. Recommended Tests

13. Unexpected CXR findings Tracheal deviation Mediastinal masses Pulmonary masses Blebs Aortic aneurysm Pulmonary edema Pneumonia Atelectasis Fractures (rib or vertebrae) Pneumothorax Cardiomegaly Dextrocardia

14. Coagulation Studies PT/PTT are not indicated in the absence of historical or physical exam findings that indicate their necessity However: prolonged surgeries or those involving excessive bleeding (orthopedic, GU, cardiac, hepatic) may indicate assessment of coagulation status

15. ASA Physical Status Classification PS-1: Normal, healthy PS-2: Mild systemic disease, no limitations HTN, DM, Obesity, COPD PS-3: Severe systemic disease with functional limitations Poorly controlled HTN, DM with complications, Angina, Prior MI, O2 dependent COPD PS-4: Severe disease that is a constant threat to life Uncorrected CHF, UA, Advanced Cirrhosis PS-5: Moribund, not expected to survive without surgery Ruptured AAA, PE, increased ICP after trauma PS-6: Brain-dead organ donor E: emergency surgery

16. Perioperative Pulmonary Issues Evaluation Risk Factors Risk Reduction

17. Pulmonary Complications Pneumonia Bronchitis Atelectasis Prolonged Mechanical Ventilation Respiratory Failure

18. Smoking Cessation Carbon monoxide reduces O2 delivery to tissues Nicotine increases pulse and vasoconstriction CO and nicotine levels normalize 24 hours after cessation Respiratory tract ciliary function returns in 2-3 days Sputum production diminishes in 2 weeks Healing is impaired in orthopedic patients who smoke vs nonsmokers The relative risk of periop complications among smokers is 1.4 - 4.3 compared with nonsmokers

19. However... Warner et al found that smokers who quit within 8 weeks of cardiac surgery had higher incidence of pulmonary complications than continued smokers 14.5% of continued smokers had complications vs 33% of those who quit within 8 weeks of surgery

20. Predicting Risk of Pulmonary Complications Six minute walk Stair climbing Symptoms explained or unexplained Cough Dyspnea Lung exam PFTs Risk Indices

21. Symptom Limited Stair Climbing Predicts Postoperative Complications 83 patients undergoing high-risk surgery were asked to climb hospital stairways as far as possible at their own pace Number of stairs climbed was the most powerful predictor, and was more useful than age, spirometry, pulmonary disease history, or weight No patient who climbed >7 flights had a complication 8/9 patients who climbed less than 1 flight had complications Defining 4 flights of stairs as good capacity was 71% sensitive and 77% specific for postop cardiopulmonary complications. It did not predict mortality.

22. More Major Pulmonary Risk Factors Age 65 or greater 40 or more pack year smoking history Maximal laryngeal height of 4 cm or less Defined as the distance from the top of the thryoid cartilage to the suprasternal notch at the end of expiration

23. Pulmonary Function Tests Usually not indicated Expensive and not sensitive Do not change management in the majority of cases Indicated in lung reduction surgery Spirometry is unreliable and should not be used to deny surgery to patients It may however be useful in patients undergoing thoracic and upper abdominal surgery who have pulmonary disease or complaints

24. Patient Risk Factors Smoking Age Functional Status Comorbidities

25. Procedure Related Pulmonary Risk Factors Surgery location Surgery time Anesthetic Neuromuscular blockade Higher incidence of postoperative pulmonary complications in patients receiving pancuronium vs vecuronium

26. Pulmonary Risk Reduction Preoperative pulmonary optimization Spinal or epidural analgesia in the high-risk patient is beneficial Adequate pain control Lung expansion maneuvers (Incentive Spirometry) Greater success when taught PRIOR to surgery Odds ratios are on the order of 0.44 for patients performing IS than those who do not CPAP, BIPAP, and IPPV are beneficial but costly and should only be used when IS is not possible or insufficient Early mobilization

27. Perioperative Renal Disease 30 day mortality for patients with ARF has a relative risk 14 times greater than those without renal dysfunction

28. Acute Renal Failure Risk Factors Hypotension Volume depletion Compromised cardiac function Prolonged bypass Nephrotoxins Postrenal obstruction (clots, hematomas, injury)

29. Preventing / Managing Renal Perioperative Complications Volume assessment and repletion Judicious use of nephrotoxins Dye, aminoglycosides, NSAIDs, ACEI/ARBs Close monitoring of GFR Urine output

30. Chronic Kidney Disease and Surgery Hyperkalemia Arrhythmias Volume derangements / CHF Infections Bleeding Uremia Hyper-/hypotension

31. Optimizing CKD perioperatively Electrolytes Volume Platelet dyfunction DDAVP Estrogen Blood products Coronary Disease Antibiotics / immunosuppression Renal dose medications Limited use of sedatives / hypnotics

32. Liver Disease Perioperatively H&P: GI bleed, encephalopathy, ascites Synthetic function: INR, albumin, bilirubin Dose medications according to clearance Limit use of sedatives and narcotics

33. Surgery in the patient with liver disease Post operative mortality is linked to Child-Pugh failure class. Class A - 10 % mortality Class B - 30 % mortality Class C - 80 % mortality Surgery 1997;122:730-5

34. Child-Pugh classification

35. Conditions affecting surgical risk Coagulopathy - bleeding risk increased Alcohol use - perioperative withdrawal Low serum albumin - fluid shifts and delayed wound healing Ascites - delayed abdominal wound healing and respiratory compromise Encephalopathy - increased post operative delirium

36. Intraoperative risks Increased susceptibility to anaesthetic effects Delayed extubation due to ascites and encephalopathy Delayed drug metabolism due to liver dysfunction, decreased albumin, cholestasis, and reduced hepatic blood flow

37. �Stress ulcer prophylaxis� Indications Coagulopathy Mechanical ventilation +/- Steroids Trauma / Burns / Closed head injury In one study at a teaching hospital, nearly 2/3 of hospitalized patients were on �stress ulcer prophylaxis� without an indication! Nearly � of study patients were prescribed �stress ulcer prophylaxis� on discharge, again without an indication!

38. Endocrine Disease Perioperatively Diabetes Adrenal Dysfunction Thyroid disease

39. Assess Diabetes Preoperatively Do not ignore diabetes Distinguish true type I from type II �Insulin dependent� and �Non-insulin dependent� are outdated and outmoded terms Type I patients ALWAYS require insulin to avoid ketosis Assess pre-admission status Glucose levels and symptoms Medications Recent HA1c Complications

40. Admission Hospitalization can increase or decrease glucose levels Increase: infection, steroids, pressors, TPN, inactivity Decrease: enforced compliance, rigid diet, decreased oral intake Diet should be individualized according to weight and comorbidities.

41. Monitoring Bedside glucose monitoring QID initially for 48 hours in all patients with diabetes Q6H if fasting Decrease to BID if fingersticks (FS) are stable Targets: Aim for BG of 90-150 mg/dL before meals ADA review recommends: Inpatients: <110 mg/dL premeal; <180 mg/dL otherwise ICU patients: 80-110 mg/dL at all times

42. Monitoring Adjust insulin regimen every 1-2 days based on glucose monitoring results Adjust dose and type of insulin in accord with lows/peaks of blood glucose over 24 hours Rapid acting insulin (e.g. Lispro) can cause hypoglycemia due to missed meals NEVER use regular insulin sliding scale as the only form of treatment

44. Oral Antihyperglycemics In the NPO patient.... Well-controlled on a hypoglycemic agent D/c oral hypoglycemic agent (OHA) and RISS; if RISS needed for >24 hours, consider a standing dose of NPH or lantus for control Well-controlled on a non-hypoglycemic agent D/c metformin (renal function, dehydration, hemodynamics, IV contrast are all considerations) TZDs OK if LFTs OK and no edema D/c acarbose � ineffective if NPO

45. Oral Antihyperglycemics If poorly controlled on oral agents, and NPO: Use insulin; RISS for 1-2 days if you want to establish requirements, or go straight to a long acting form

46. Insulin treated patients Type I and NPO: Insulin drip or 1/2-2/3 of medium or long acting dose and RISS Use D5 Check FS q6 Use short acting if rapid correction required Always use insulin in Type I patients, otherwise they will develop ketosis, even with unelevated sugars

47. Insulin treated patients Type II and NPO: May require ISS alone Give � medium or long acting dose alternatively Use D5 unless markedly hyperglycemic FS q6 hours NB: Type II diabetics that are brittle or insulinopenic may be better treated as Type I diabetics when NPO

48. Hypoglycemia If patient is cooperative, give 15-30 g of carbs 8 oz juice or soda is 30 g; 2 graham crackers is 10 g of carbs 15 g of carbs will raise BG 25-50 mg/dL Non-alert: 1 amp D50 (25 g dextrose); 1 mg glucagon IM if no IV access, and can repeat q15 minutes. If severe, recurrent, or due to long acting agent, use D5 or D10 drip (D20 requires central line)

49. Perioperative DM management General rules: Preferably schedule procedure for the morning BG should be checked q1-2 hours before, during, and shortly after the procedure RISS only is again discouraged since poor control may result

50. Perioperative DM management Type I These patients need insulin at all times; otherwise ketosis will develop in 12-24 hours Use an insulin drip with D5 at 75-125, target BG 100-150 mg/dL Alternatively, � to 2/3 of NPH the morning of the procedure. Lantus can be given the night before, however it is reasonable to reduce the dose by 25% High BG can be controlled with low doses of short acting insulin

51. Perioperative DM management Type II Ketosis will not develop; glucose may be elevated but usually improves Hold hypoglycemic agents the day of the procedure and restart with normal diet Metformin should be held the day of procedure and can be restarted 2 days later if stable Long acting metformin should be held the night prior Acarbose should be held TZDs can be continued, although 1-2 doses missed will likely not matter since effects are sustained

52. Perioperative DM management Type II If on insulin: Give � of NPH dose the AM of procedure No short acting unless BG over 200 mg/dL, and if then use small doses Lantus can be given at usual dose the night before, or reduced by 20% Alternatively, an insulin drip with D5 can be used, with target BG of 100-150 mg/dL

53. Insulin Drip Indications DKA Hyperosmolar hyperglycemic state Very poorly controlled diabetes TPN Type I DM perioperatively, NPO, or in labor Post-MI with hyperglycemia Any ICU patient with hyperglycemia Poor absorption of SC insulin

54. How to prepare an Insulin Drip Regular Insulin 100 Units in 1 liter � NS or NS; 1 unit = 10 cc If fluid restricted, then Regular Insulin 100 units in 100 cc of 1/2NS or NS; 1 unit = 1 cc Run 10 cc of solution through tube at initiation When transitioning to SC insulin, give short acting insulin 1-2 hours before stopping drip, or medium acting insulin 2-3 hours before

55. Primary care aspects of inpatient diabetes management Assess HA1c q3-6 months, goal < 7% BP <130/80 by JNC VII guidelines Lipid screening qyear (LDL < 100, TG < 150, HDL > 40 in men, > 50 in women) BUN/Cr/microalbumin qyear Foot care / vascular disease every visit EKG qyear Fundus exam qyear Smoking cessation every visit Vaccinations � influenza, pneumonia ASA 81 mg qd if over 40 years old Activity, weight loss, diet

56. Adrenal Dysfunction There is a variance of opinions about the need for stress dose steroids One approach is to assess patient status and perioperative needs along with surgical stress, and give steroid only if signs of adrenal insufficiency present The other approach doses preemptively

57. Steroid Supplementation Who is at risk ? - Pts who have received > 20 mg/day of prednisone ( or equivalent ) for more than 3 weeks during the preceding year. - Any patients with clinical Cushings syndrome. Who is not ? < 5 mg/day of prednisone. Alternate day glucocorticoid therapy.

58. Steroid Supplementation Stratify patients who take 10 mg of prednisone (or equivalent) per day according to degree of surgical stress. Coursin et al JAMA. 2002;287:236-40

59. Surgical Stress Dose Steroids (one method among others) Minor procedures: take usual dose Moderate stress procedure: take usual morning dose, then hydrocortisone 50 mg just prior to procedure, then 25 mg IV q8 hours x 24 hours, resuming usual dose thereafter Major procedures: usual morning dose, hydrocortisone 100 mg IV just prior to procedure, then 50 mg IV q8 hours x 24 hours, then taper by half per day to usual dose

60. Stress Levels Minor: inguinal hernia repair, cutaneous procedure, colonoscopy, mild viral illness Moderate: cholecystectomy, most orthopedic procedures, hemicolectomy, pneumonia Major: cardiothoracic, extended abdominal organ resections/manipulations, pancreatitis

61. Why Perioperative Steroids Can Be Bad Hyperglycemia Impaired healing Immunosuppresion Hypertension Delirium Fluid retention / edema Gastric ulceration

62. Rheumatologic Perioperative Considerations Steroid dependence DMARDS Cervical Disease Temporomandibular Disease Cricoarytenoid Arthritis Immunosuppression Nutritional Deficiency Operative Positioning

63. Methotrexate Perioperatively No clear evidence for or against holding methotrexate perioperatively Considerations include wound healing, bone marrow function, and renal function If held, MTX should be stopped one week before and one week after the procedure

64. TNF-a Inhibitors and Surgery There are no definitive guidelines regarding anti-TNF biologic agents perioperatively However, it is reasonable to stop them perioperatively, and wait two weeks postop to restart Infliximab should be infused 6 weeks prior to surgery Entanercept can be given up to 2 weeks prior to surgery

65. Atlanto-axial Instability Preoperative flexion/extension views of the cervical spine are imperative for patients with RA Atlantoaxial instability is often asymptomatic C1-2 fusion may be necessary

66. Summary Assess risks by history and exam Obtain indicated labs Avoid unnecessary studies Optimize according to disease and procedure Monitor organ function postoperatively Counsel the patient about pre- and postoperative events and expectations Reevaluate analgesia continuously

67. Acknowledgements Stoelting, RK and Miller, RD. Basics of Anesthesia. Philadelphia: Churchill Livingstone, 2000. Duke, J. Anesthesia Secrets. Philadelphia: Hanley & Belfus, Inc., 2000. Smetana, GW. Preoperative Pulmonary Evaluation. N Engl J Med 340:12, 937-944. Lazarus M. Lectures on Renal, Hepatic, and Adrenal Diseases. Hospitalist Database. UCLA Medical Center, 2005. American Diabetes Assoc. Diabetes Care 27: S95, 2004. Inzucchi S. Diabetes Facts and Guidelines. Yale Diabetes Center, 2005.