Medical Problems In The Surgical Patient Dr Osama Bawazir FRCSI, FRCS(Ed), FRCS (glas), FRCSC.

1. Medical Problems In The Surgical Patient Dr Osama Bawazir FRCSI, FRCS(Ed), FRCS (glas), FRCSC.

2. Introduction • “A chance to cut is a chance to cure” • “Nothing heals like cold, hard steel” • Surgery = stress and insults • Physiology of surgery • Maximize pre-operative condition of patient • Preoperative evaluation: H&P • Perioperative care: think of what can kill first...

4. Perioperative medical care: • Surgical emergency • Cardiac disease • Pulmonary disease • Renal dysfunction • Liver dysfunction • Diabetics • Bleeding disorders • Malnourished

5. Perioperative medical care: • Surgical emergency • Cardiac disease • Pulmonary disease • Renal dysfunction • Liver dysfunction • Diabetics • Bleeding disorders • Malnourished

6. Patient-related risks Chronic lung dz – wheeze, productive cough Smoking General health Obesity Age? separate from others? Procedure related risks Type of anesthesia GETA alone  FRC 11% inhibited coughing peri-op Surgical site Duration of surgery Pulmonary disease

7. Modifiable pulmonary risks • Obesity physiology •  lung capacity, FRC, VC •  WOB • hypoxemia • Tobacco • Definition of “stopped smoking”.... • “When was your last cigarette?”

8. Pre-operative risk assessment: pulmonary function • Patient history • unexplained dyspnea, cough, reduced exercise tolerance, OSA • Physical exam: • wheeze, rales, rhonchi,  exp time,  BS • 5.8x more likely to develop pulmonary complications* • Pre-operative CXR is mandatory over 40 yo • ABG • no role for routine use • result should not prohibit surgery • caution if  PaCO2 * Lawrence et alChest 110:744, 1996

9. Respiratory problems • second only to cardiovascular events as a cause of perioperative death. • Several risk factors ↑pulmonary complications, including • age • male gender • emergency surgery • ASA status • length of the surgery. • The main two specific factors • pre-existing respiratory disease • surgery of the chest or upper abdomen. • Clinically: • Atelectasis • bronchospasm • retained secretions • infectious complications

10. EFFECT OF SURGERY AND ANAESTHESIA ON RESPIRATORY FUNCTION • Ventilation • Opioids can produce profound respiratory depression. • The inhalational anaesthetics halothane, enflurane, and isoflurane also depress respiratory drive. • Lung volumes • functional residual capacity is reduced during general anaesthesia by about 20 per cent below the value measured in the awake, supine position. • the diaphragm ascended into the chest by about 2 cm during anaesthesia with or without paralysis • Gas exchange • V/ Q mismatch • Elimination of CO (changes in the ratio of dead space to tidal volume )

11. Host defences • dryness tends to damage the respiratory epithelium. • The cough mechanism is depressed during anaesthesia • the immune system is altered in the immediate postoperative period

12. 1.The alveolar/arterial Po2 gradient is increased during anaesthesia, and this change is markedly affected by age. 2.The decrease in Po2 is secondary to an increased distribution of flow to areas of decreased ventilation, most commonly the dependent areas. 3.The increase in VD/ VT seems to be secondary to increased distribution of ventilation to areas of lesser perfusion. 4.The major differences are between the awake and anaesthetized state; paralysis and controlled ventilation do not greatly alter overall gas exchange.

14. Management • Estimate function: • Clinical and Specialist opinion. • ABG • CXR • Spirometry: FEV1/FVC, PEFR • Chest infection: • Postpone for 2 weeks • Antibiotics & Physio. • COPD • Leis with specialist • Reschedule surgery. • Plan to transfer to ICU for mechanical ventilation pending: Lung function, type & duration of surgery. Optimization of pulmonary function • Chest physical therapy • Pharmacological therapy • NON-INVASIVE RESPIRATORY MONITORING • ANAESTHETIC TECHNIQUE

15. Smoking • 10 cigr.=6 fold increase in post-op respiratory complications. • Respiratory and CVS effects • Carbon monoxide has higher affinity for O2 than Hb. • Nicotine increases heart rate and BP. • Hypersecretion of thick mucus • Immunosuppressive • Stop 3 months= improve pulmonary functions • Stop 1-2 days= Decreases CO levels.

16. “Surgeons as medical doctors”Smoking cessation • 83% of patients think MD’s are against smoking • 55% think THEIR DOCTOR is against it • 55% say their MD has never advised to quit smoking • despite that 22% say MD inquired of smoking hx • MD can make a difference • 81% have tried to quit if MD says to • 61% have tried to quit if MD says nothing • Pts less likely to try to quit if advised to “cut down” * Mullins and Borland, Aust Fam Physician 22(7):1146, 1993.

17. Age • Distinction must be made between physiological state and chronological age. • Are less mobile, intercurrent disease, less physiological reserve. • Caution with regards to: • IVF & Narcotic analgesia. • More likely to have wound infection. • In 65 CVA 1%, In 80 CVA 3%

18. Obesity • BMI> 30 • Increased risk in: • DVT, • Wound infections & Dehiscence • Respiratory complications & sleep apnoea. • Intercurrent diseases. • Operative difficulty • Relative risk of mortality 3-5 • Advise controlled wt reduction • Arrange ICU post-op

19. Cardiovascular Diseases Predictors Major: • Unstable coronary syndrome. • Decompensated CCF. • Significant Arrhythmias • Severe valvular disease Intermediate: • Mild angina • PMH MI • Compensated CCF • DM Minor Age, abnormal ECG..etc

20. CARDIOVASCULAR DISEASES • Recent infarction • EF< 40% • left ventricular failure • Persistence of angina after infarction • Angina • Silent ischaemia • Coronary artery bypass grafts

21. Chest Pain Work Up • History of event • Physical exam • 12-Lead ECG • CXR • ABG • Cardiac Panel • BMP, M/P, CBC, PT, PTT, INR • Chart Review

22. Tachycardia • Delivery O2=1.34 hgb X O2 sat X SV X HR • Hypovolemia (Think Bleeding) • Anemia • Hypoxemia • MI • Arrhythmia • PE • Pain • anxiety

23. MI arrhythmias CHF X X medical therapy will cover later. . . Cardiac disease in peri-op period • CAD can cause any of these • Risks for CAD: • age, sex, HTN, XOL, DM, tobacco • Modify those risk factors you can...

24. Coronary Artery Disease • Definition of CAD.... • Physiology of surgery: •  myocardial oxygen demand •  catecholamines:  HR,  contractility, PVR •  HR also causes decreased diastolic filling • Coronary arteries fill in diastole • Less blood flowing in coronaries: less myocardial O2 supply

25. Myocardial Infarction • Pt without risks has 0.5% chance of MI • Pt with risks has 5% chance of perioperative MI • Perioperative MI has 17-41% mortality • CAD causes MI....look at PMH • Risk stratifications:

26. Myocardial infarction • O2 supply / demand imbalance: ANGINA • Surgical stress increases demand • Treatment – “MONAB” • Morphine • Oxygen • Nitroglycerin • Aspirin • Beta-blockers • Cardiac panel (troponin, CK-MB), ?Heparin

27. Prevention of perioperative cardiac events • Wait 6 months if possible • Beta-blockade* • 200 pts with CAD or risk factors for CAD • atenolol pre-op and peri-op in ½ • MI reduced 50% in first 48h • 2 year mortality 10% vs 21% • Maintain peri-operative normothermia •  cardiac events, esp. arrhythmias • Treat peri-operative hypertension * Mangano NEJM 335:1713, 1996.

28. Prevention of perioperative cardiac events • Invasive monitoring (Swan Ganz) – no help • Pre-op CABG (CARP trial) – no difference • American College of Cardiology / AHA now recommends CABG in preop pts who ordinarily meet CABG criteria: • L main dz • 3V dz with LV dysfxn • severe prox LAD stenosis • MI despite maximal medical Rx

29. Prevention of perioperative cardiac events • Watch for and treat arrhythmias Causes? Treatment? Drugs, electrolytes, ischemia, fluid shifts, body T underlying cause, rate control, conversion

30. Arterial hypertension • Heart failure • Valvular disease • Cardiomyopathies • Cerebrovascular disease • Peripheral vascular disease • Dysrhythmias and heart blocks

32. Action: • Evaluation: Clinical, Specialist opinion, ECG, Stress ECG, CXR, Echo ..others(Holter monitoring, Exercise electrocardiography, Nuclear imaging, Cardiac catheterization) • IF Major: • Cancel unless life threatening • Consider CABG prior to elective surgery. • If intermediate: • Objective performance. • Hypertension: • Indicates CAD • More likely to develop hypotension during surgery. • Control prior to surgery.

33. Perioperative medical care: • Surgical emergency • Cardiac disease • Pulmonary disease • Renal dysfunction • Liver dysfunction • Diabetics • Bleeding disorders • Malnourished

34. Patients with special preoperative needs • 37 yo WM with longstanding type I DM and with ESRD for 20 years, HD dependent, severe retinopathy, and s/p multiple LE amputations for non-healing diabetic ulcers. • Admitted for Abx for wound infection • Evening RN calls you for “nausea and sweating”

35. Patients with diabetes • Possible occult CAD (diabetic neuropathy) • Look for “anginal equivalents” • SOB • Nausea • “All patients with longstanding DM have CAD” • EKG, cardiac enzymes

36. Patients with diabetes • Hyperglycemia facilitates infection • Warm medium with food for bacteria • Treat suspected infection aggressively • Tight glucose control is one of 2 therapies that has been shown to improve outcome of septic patients in the ICU • What is the other?

37. Diabetes • Patients are more sensitive to protein depletion, U&E& glucose imbalance. • Surgical stress can precipitate DKA. • DKA is a cause of acute abdomen • Decreased phagocytosis, neutrophil activation and antibody production • Small vessel disease • Peripheral vascular disease • Peripheral neuropathy • Autonomic neuropathy • Recognition of hypo/Hyperglycaemic attacks

38. Management Specialist Opinion required

39. Renal: • Identify the cause: • Pre-renal, eg: cardiac, hypovolaemia • Renal, eg: acute tubular necrosis( drug induces) • Post renal, eg: obstructive uropathy. • Identify pt for renal dialysis. • Check K levels • Accurate fluid balance • Look for signs of fluid overload. • Do not misinterpret poly ureamic phase

40. Perioperative medical care: • Surgical emergency • Cardiac disease • Pulmonary disease • Renal dysfunction • Dialysis dependent • Liver dysfunction • Diabetics • Bleeding disorders • Malnourished

41. Renal dysfunction • Not all renal failure is oliguric • H&P • Check BUN/Cr • Assume DM have CRI • Volume status • Electrolytes.....sequelae? • Which ones? • Drug metabolism

42. Renal dysfunction • Dialyze preop to improve electrolytes, volume status • No K+ in MIVF • Very judicious MIVF while NPO • Altered drug metabolism • Altered platelet fxn

43. Post op care In renal failure • Fluid and electrolyte balance • Anaemia and bleeding • Drug prescription

44. ACUTE RENAL FAILURE

45. MANAGEMENT • Diagnosis • Exclusion of obstruction • Recognition and correction of prerenal failure • Recognition of pre-existing chronic renal failure • Immediate management and indications for urgent dialysis • Prophylaxis and attempts at reversal

46. haematological Disorders

47. Liver disease • Chronic renal failure • Vitamin K deficiency • Anticoagulants • Massive blood transfusion • Cardiopulmonary bypass • CONGENITAL DISORDERS OF COAGULATION e.g Haemophilia

49. haematological Disorders • Anaemia • Correction 1 week pre-op • Correction day preop is undesirable • Haemodilution • Thrombocytopaenia • In splenomealy, Platelets must be transfused immediately preop and on ligating the arterial supply. • Sickle cell disease • Crisis caused by : dehydration, infection, hypoxia, hypothermia. • Jaundice & anaemia • Splenic infarctions: sepsis • Prevention: Warm, well hydrated, well analogised • Consider exchange transfusion in SS • Correction of coagulopaties

50. THROMBOPHILIA • HAEMOGLOBINOPATHIES • Sickle-cell disease • Sickle-cell trait • Thalassaemia • MYELOPROLIFERATIVE DISORDERS • LYMPHOPROLIFERATIVE DISORDERS • AUTOIMMUNE DISORDERS e.g Idiopathic thrombocytopenic purpura