Perioperative factors with surgery

Postoperative myocardial ischemia, infarction, unstable angina and death associated with coronary artery disease is common place.

About 30% of patients undergoing surgery annually in the U.S. have coronary artery disease.

The presence of coronary artery disease or risk factors from such disease markedly increases cardiac morbidity and mortality.

Perioperative cardiac events are thought to be related to coronary plaque rupture, myocardial oxygen supply demand mismatch, or combination.

In patients with coronary artery disease undergoing major noncardiac surgery the frequency of significant postoperative cardiac complications of nonfatal myocardial infarction, pulmonary edema, ventricular tachycardia, or death is 5.8% (Goldman L et al).

In patients with underlying cardiovascular disease such as peripheral artery disease or stroke, have an increased risk of perioperative cardiac complications and a higher incidence of significant coronary artery disease: this population has a five times higher rate of left ventricular systolic dysfunction-left ventricular ejection fraction less or equal than 40% (Kelly R et al).

Factors associated with surgical risk and coronary artery disease includes blood loss, volume shifts, enhanced myocardial oxygen demand, increased postoperative platelet reactivity and myocardial ischemia.

Patients who smoke have an increased risk of perioperative complications including healing and cardiopulmonary vascular complications.

One third of patients orthopedic patients receiving surgery receive a blood transfusion in the perioperative period.

Red cell transfusion during hospitalization for noncardiac surgery is associated with long-term mortality.

The most common endocrine issues affecting surgical patients arevdiabetes, thyroid disease, and the role of stress-dose corticosteroids for patients with actual or potential hypothalamus-pituitary-adrenal axis suppression.

physiologic changes associated with surgery includes the up regulation of catecholamines, cortisol, inflammatory cytokines, decreased insulin sensitivity and increased secretion of glucagon and growth hormone.

Surgery leads to the up regulation of gluconeogemesis glycogenolysis, lipolysis, proteolysis, and ketogenesis, resulting in hyperglycemia and potentially ketoacidosis im severely insulin deficient patients.

These physiologic changes result in increased perioperative morbidity and mortality seen among patients with diabetes.

Diabetics also have high risk for cardiovascular disease, hypertensive disease, renal disease, cerebrovascular disease, autonomic neuropathy, and obesity.

Patients with diabetes have an elevated postoperative mortality rate for both short and long term noncardiac surgeries compared with matched nondiabetic patients: most deaths are attributed to  cardiovascular disease.

Diabetic patients are more likely to have post operative respiratory infections, surgical site infections, UTIs, acute kidney injury, intensive care unit admission, and increased hospital length of  stay then patients without a diagnosis of diabetes.

There is not sufficient evidence to support routine pre-operative testing of blood glucose or hemoglobin A1c in otherwise healthy patients undergoing elective non-cardiac surgical procedures because testing does not reduce postoperative morbidity and mortality.

It is reasonable to screen patients undergoing joint replacement or vascular surgery because patients in these groups with elevated preoperative hemoglobin A-1 C have a higher incidence of cardiac infectious complications.

Fructosamine correlates more closely with perioperative risk than hemoglobin A-1 C, as glycated protein fructosoamine reflect serum glucose levels over the preceding 2 to 3 weeks as opposed to 2 to 3 months.

In patients with diabetes undergoing total joint arthroplasty, elevated fructosamine levels of greater than 292 µmol per liter is associated with a significant higher risk of postoperative deep infections, readmission and operative reintervention.

The UPSTF recommends screening for diabetes in adults age 40 to 70 years who are obese and repeating, screening every three years if values are normal.

It is reasonable to postpone elective surgery in patients with hemoglobin A1c levels higher than 8%.

Additional risk factor screening includes history of cardiovascular disease, hypertension, hyperlipidemia, polycystic ovarian syndrome, or gestational diabetes, a first-degree relative with diabetes, or a higher risk resort ethnicity.

In patients with diabetes it is reasonable to obtain a hemoglobin A-1 C if no level has been obtained in the last three months.

Post operative glucose levels correlate with surgical complication rates more than preoperative hemoglobin A-1 C.

Non-insulin antidiabetic medication regimens are adjusted in the perioperative period to minimize the risk of hypoglycemia while the patient is fasting.

In general,  such medication should be withheld starting the morning of the procedure and can be restarted on discharge when the patient has resumed a normal diet.

SGLT2 inhibitors should be held for three days before surgery to avoid the risk of diabetic ketoacidosis.

Diabetic ketoacidosis is a rare adverse effect of SGLT2 inhibitors, which may be precipitated by surgery.

Dipeptidyl peptidase-4 inhibitors can be continued throughout the perioperative period, without increased hypoglycemic events.

For a patient with diabetes type I, long acting basal insulin should be provided to prevent development of ketoacidosis.

Intermediate acting insulin should be reduced by 50% the morning of surgery because it provides a meal time coverage for the midday meal, which usually will be skipped the day of surgery.

intermediate acting insulin should be reduced by 50% the morning of surgery because it provides a meal time coverage for the midday meal, which usually will be skipped the day of surgery.

Short acting insulin and rapid acting insulin analogues should be withheld the day of surgery where the patient is fasting.

Perioperative hyperglycemia is associated with increased length of stay in the hospital and in ICUs, wound infections, and myocardial infarctions.

Cardiac surgery patients with intraoperative hyperglycemia have increased risk of postoperative death and pulmonary and renal complications: For each 20 mg/dL increase in the mean glucose level there is a 30% increase risk of adverse events.

Patients with glucose levels greater than 180 mg/dL pre and post op, have an increase risk of infection, death, reoperation, and anastomotic failures in patients undergoing elective colon, rectal and bariatric surgeries.

Decrease rates of adverse events occur with better levels of glucose control, and the lowest rates occur when is the glucose levels unless that 130 mg/dL.

Target glucose range is 80 to 180 mg/dL in the perioperative period.



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