Peri-Operative Medicine – “ Nuggets” from the Consult Service

1. Peri-Operative Medicine – “Nuggets” from the Consult Service Guest Speaker – Glenn Newell M.D. Presenter – Rinku Bhatia M.D.

2. Case 1 • 63 year old Caucasian M with a long hx of osteoarthritis comes into the hospital for bilateral knee replacements. He has a history of hypertension on Norvasc, Lisinopril and Hydrochlorothiazide. On post op day 1 while getting out of bed for physical therapy his blood pressure falls to 70 /30 and he is tachycardic and lightheaded.

3. Case 2 • A 64 year old African American male is admitted to the hospital for laparoscopic bowel surgery. He has a history of hard to control blood pressure. Renal function is normal. On day one post op he is npo and his blood pressure is 210/110 and has been resistant to intravenous beta blockers, ace inhibitors and hydralazine

6. Management of HTN in Pre-Operative patients • Patients who are taking chronic antihypertensive medications should continue taking their medication until the time of surgery. • The ideal circumstance is to normalize blood pressure (eg, to less than 140/90 mmHg) for several months prior to elective surgery. • In a study published in JAMA that included 196 pts, with a BP < 180/110 mmHg observed no difference in peri-operative outcome and they may proceed to surgery safely • Studies have found that a diastolic pressure over 110 mmHg immediately before surgery is associated with a number of complications including dysrhythmias, myocardial ischemia and infarction, neurologic complications, and renal failure

8. Management of HTN in Pre-Operative patients • B-blockers: • ACE/ARB: • Ca channel blockers: • Diuretics: • Central sympatholytics: Clonidine

9. Management of HTN in Post-Operative patients • Any patient who experiences a marked rise in blood pressure following surgery should be treated. • Remedial causes of hypertension such as pain, agitation, hypercarbia, hypoxia, hypervolemia, and bladder distention should be excluded or treated. • Patients on chronic antihypertensive therapy should resume their usual medications postoperatively as needed. • Those who cannot take oral medications should be given a comparable alternative.

10. Management of HTN in NPO Post-Operative patients • Patients taking beta blockers may be given parenteral propranolol, labetalol, or esmolol. • Patients taking an ACE inhibitor may be given parenteral enalaprilat. • Patients taking centrally acting agents can be given a clonidine patch. • Patients taking calcium channel blockers can be given intravenous nicardipine • Patients taking diuretics may be given parenteral furosemide or bumetanide

11. Case 3 • A 55 year old gentleman  is admitted to the hospital for elective hip replacement.He has well controlled diabetes mellitus on Glimepiride and Metformin (HgbA1C 6.4). He also takes Diovan and Hydrochlorothiazide for hypertension. On post op day 2 he is well and undergoing physical therapy when the orthopedics nurse practitioner calls you to say his creatinine is now 2.3 (was 0.8 pre operatively).

12. What could be the cause of the patient’s elevated Creatinine?

13. Effect of ACE-I & ARB on Renal function • ACE inhibitors and angiotensin II receptor blockers can theoretically blunt the compensatory activation of the renin-angiotensin system during surgery and result in prolonged hypotension. • In one study 51 patients undergoing peripheral vascular surgery were randomly assigned to ACE inhibitor continuation or withdrawal. Patients continuing ACE inhibitors through the morning of surgery had significantly more episodes of hypotension requiring treatment compared with patients who stopped therapy at least 12 hours captopril or 24 hours enalapril before surgery. No difference in the incidence of hypertensive episodes was noted between the two groups. • A second study randomly assigned 40 patients with good left ventricular function who were undergoing coronary artery bypass graft surgery to continue or omit ACE inhibitors before surgery. Patients who omitted their ACE inhibitors required less vasopressors during surgery but required more vasodilators to control hypertension in the early postoperative period. • Angiotensin II receptor blockers (ARBs) have similar physiologic effects as ACE inhibitors on hypertension and renal perfusion. It is not surprising then that a study in vascular surgery patients found a statistically significant increase in the number of hypotensive episodes in patients treated with ARBs prior to surgery compared with those treated with beta blockers or calcium channel blockers

17. Management of ACE-I & ARB in peri-operative period • Findings suggest that continuing ACE inhibitors up to the time of surgery increases perioperative hypotension, but possibly reduces the incidence of postoperative hypertension. • While the data do not lead to clear recommendations, we continuing ACE inhibitors in patients who are taking them for the management of hypertension. • Substitution of shorter acting drugs (eg captopril) may allow more flexibility for patients with postoperative labile blood pressure. • On the other hand, it would be reasonable to withhold ACE inhibitors one dose interval before surgery in patients who are taking them for heart failure, particularly if the baseline blood pressure is low, to avoid significant hypotension during anesthesia induction.

18. Case 4 • 85 yr old M was climbing up a ladder when he slipped and fell. CT Scan of his head revealed Subarachnoid hemorrhage. As per neurosurgery no surgical intervention was necessary. Pt is admitted under the Trauma Service. • PMH is significant for HTN, HPL, DM which are well-controlled. • Patient’s started on Metoprolol 25 mg BID, Lipitor 20 mg daily, Lantus 10 Units sq HS, Insulin Aspartate 6 Units TID-AC and started on Famotidine 20mg iv q12hrs. • Nurse from trauma step down calls to inform you that the patient has had a change in mental status.

19. What could be the cause of patient’s change in mental status and how would you manage it?

22. Post-operative Delirium • Delirium, or acute confusional state, is a syndrome characterized by an acute change in cognition with altered consciousness and impaired attention that fluctuates over time. • It is a common problem associated with serious complications and often goes unrecognized and untreated. Delirium may be the sole indicator of a serious underlying illness.

24. Post-op Delirium • Delirium is associated with increased morbidity and mortality in hospitalized patients. • Patients who develop delirium are at higher risk for falls, pressure ulcers, and pneumonia. They have higher rates of functional decline, loss of independence, and institutional care. • Delirium goes undetected in 33% to 66% of cases.

25. Etiology of delirium • The etiology of delirium is usually multi factorial and involves a complex interaction between a vulnerable patientwith predisposing risk factors and exposure to precipitating insults.

26. Etiology of delirium • A patient with many predisposing risk factors is at high risk for developing delirium from minor insults, such as a urinary tract infection or a single dose of a medication with anticholinergic activity. • Conversely, a patient with few predisposing risk factors will develop delirium only when exposed to multiple or severe stressors, such as critical illness and psychoactive medications.

29. Preventive measures • Routine screening of cognitive functions and delirium (eg, Mini-Mental Status Examination on admission and CAM during hospital stay) • Non pharmacologic, uninterrupted sleep promotion (eg, noise reduction and lighting control) • Restoring visual and hearing aids • Fluid and electrolyte balance • Nutrition • Mobilization • Avoidance of bladder catheters and physical restraints • Elimination of unnecessary medications • Adequate pain control • Regulation of bowel/bladder function • Orientation (eg, use of clocks and calendars)

30. Management of Delirium • Delirium is a medical urgency • Uncerlying cause should be identified and treated • Modify risk factors • Provide supportive care (eg, hydration, nutrition, and skin care) • Prevent complications (eg, infections, aspiration, falls, deep venous thromboses, or pressure ulcers) • Treat the behavioral symptoms

31. Management of Delirium • Initial evaluation should include a focused history and physical examination and a search for reversible causes. Hypoglycemia, hypoxia, hyperthermia, hypertensive encephalopathy, thiamine deficiency, withdrawal states, and substance-induced delirium are readily identifiable and treatable disorders.

32. Management of Delirium • The history gathered should include baseline cognition level, the acuity of the change in mental status, a careful assessment for occult alcohol and benzodiazepine use, recent falls, last bowel movement, and urinary output. • It is critical to review the home and in-hospital medication lists with dosages, especially as-needed and over-the-counter drugs. All potentially offending and unnecessary medications should be discontinued if possible. • The physical examination should focus on vital signs, pulse oximetry, volume and cardiopulmonary status, skin/wounds, abdominal abnormalities, and the neurologic assessments. A blood glucose value should be obtained upon initial evaluation.

33. Management of Delirium • Initial testing should include: • CBC, BMP, LFT, UA • Chest radiography, ECG •      Additional laboratory testing, if necessary, and may include: • Serum osmolality • Drug levels (eg, digoxin, lithium, carbamazepine, phenobarbital, phenytoin, depakote, tricyclic antidepressants, and cyclosporine) • Toxicology screen • Arterial blood gas levels • Cardiac enzymes • Thyroid function tests • Cortisol level • Vitamin B12 levels • Ammonia levels • Blood cultures

34. Management of Delirium • Neurologic imaging is indicated if there is a new focal neurologic sign, a history of recent falls or head trauma. A lumbar puncture is indicated if there are meningeal signs and fever and/or headache (ie, concern for meningitis or encephalitis). An EEG has a limited role in the diagnosis of delirium, but it can help to exclude subclinical seizures and to confirm the presence of encephalopathies.

35. Management of Behavioral symptoms of Delirium • Nonpharmacologic approaches to managing symptoms of delirium should be instituted in all patients. These include:- • Creating a calm, comfortable environment • Restoring sensory aids • Using orientation strategies (eg, communication, clocks, and calendars) • Involving family members in supportive care • Limiting room and staff changes • Allowing uninterrupted sleep at night • Encouraging wakefulness and mobility during the day

36. Management of Behavioral symptoms of Delirium • Pharmacologic therapy is indicated if the patient is a danger to himself, staff, or others; the symptoms would interrupt essential therapy (eg, intubation or pulling out IV lines); or the symptoms do not respond to nonpharmacologic interventions • Antipsychotic medications are the agents of choice. • Haloperidol been studied and employed extensively to treat delirium, has multiple routes of administration (oral, IM, and IV), a relatively rapid onset of action with the IM and IV routes, and is inexpensive. • Benzodiazepines should not be used to treat delirium because they may precipitate confusion, especially in the elderly, and are associated with worsening of delirium. BZDs should be reserved for use in patients undergoing sedative and alcohol withdrawal, those in whom there is a contraindication to antipsychotics, or those with the neuroleptic malignant syndrome • Physical restraint is an exceptional measure that may be indicated if other less restrictive means have failed and the patient’s behavior puts the staff and/or the patient at risk. Restraints can increase agitation in a delirious patient. Reevaluation of their use should occur regularly.

37. Case 5 • 38 yo F with pmh of Lupus, diagnosed 7 yrs ago, managed with Prednisone 7.5mg po daily and Methotrexate 7.5mg qweekly. Her last flare up which was manifested by arthralgias, fever and rash was 8 months back. Pt is admitted at CUH for cholecystectomy. Surgical service consults you to manage patient’s medications perioperatively.

38. Management of steroids peri-operatively • Prolonged use of corticosteroids may suppress the normal increase in endogenous cortisol that occurs in response to the stress of surgery. Supplementation of corticosteroids may therefore be needed to mimic the body's own response to stress.

40. Management of Methotrexate peri-operatively There is little evidence to suggest that stopping methotrexate preoperatively reduces the incidence of infection or improves wound healing. This was illustrated in a study of patients with RA having elective orthopedic surgery; 388 patients were randomly assigned to continue weekly methotrexate before and after surgery or to hold methotrexate for two weeks before and after their operations. Postoperative infections and other complications were significantly less frequent in those who continued methotrexate than the others (2 and 15 percent, respectively). Postoperative flares of arthritis were not seen in those who continued methotrexate but developed in 8 percent of those who stopped the drug.