Preoperative evaluation

The Joint Commission and Centers for Medicare and Medicaid Services mandate that all patients undergo a comprehensive medical history and physical examination within 30 days before surgery, regardless of the type of surgery, anesthesia care, or medical profile of the patient.

For noncardiac surgery a detailed history and assessment of exercise tolerance, physical examination, resting electrocardiogram are used for the initial estimate of perioperative cardiac risk.

The history should identify cardiovascular conditions associated with perioperative major adverse cardiovascular events (MACE), that includes history of ischemic heart disease, coronary stent, heart failure, arrhythmias, valvular heart disease, hypertension, and pulmonary hypertension.

Cardiovascular disease risk factors including kidney disease and diabetes, are associated with up to three fold increase risk of cardiac events.

Evaluation requires the understanding of surgical stress response that is activated by afferent input to the hypothalamus from the site of tissue injury, resulting in endocrine metabolic and inflammatory responses.
Assessing a patient’s work load performance as 4 or greater metabolic equivalent tasks (METs) without symptomatic limitation, consisting of walking up a hill or climbing up two or more flights of stairs.
Preoperative subjective assessment of METS is approximately 20% sensitive for identifying patients who are an able to achieve for MET‘s during cardio pulmonary exercise testing.
The presence of exertional chest pain, dyspnea, orthopnea, palpitations, recent syncope, and physical examination findings, such as a diastolic murmur of any grade or a grade 3/6 systolic murmur, gallops, jugular venous distention, or edema, may  indicate cardiovascular disease.
The presence of high risk area conditions such as acute coronary syndrome’s or decompensated heart failure or contraindications to surgery.
Preanesthetic medical evaluation risk assessment requires analysis of surgical urgency, surgery specific risk, patient specific risk, and the status of relevant comorbidities.
Urgent or emergent status increases the risk of complications over similar procedures performed electively.
Multiple cardiovascular risk factors such as hypertension and hyperlipidemia are present in 45% of patients age 45 years or older undergoing non-cardiac surgery.
Nearly 25% of patients undergoing non-cardiac surgery have a history of atherosclerotic cardiovascular disease.
The incidence of perioperative cardiovascular events is related to the risk for cardiovascular events in an individual patient before surgery.
In a retrospective study of more than 10 million hospitalizations for non-cardiac surgery in adults, the combined rate of perioperative death, myocardial infarction and acute ischemic stroke was 3.0%.
Definitions/classification of surgical urgency: emergency surgery: life or limb threatened without intervention within six hours: urgent surgery: life or limb threatened without intervention within 24 hours: time sensitive surgery: medically necessary to operate within 1 to 6 weeks, and elective: can we deferred for up to one year.
The intrinsic risk of a surgical procedure depends on the amount and location of tissue disruption, blood loss, fluid shifts, and hemodynamic effects.
Endocrine stress response includes increased levels of cortisol, ACTH, catecholamines, renin, and ADH.
Salt and water metabolism are influenced by the ADH response promoting free water retention and the production of a concentrated urine, and the renin/aldosterone system which promotes sodium and water reabsorption.
Surgical inflammatory response is driven by the release of cytokines-IL-1, IL-6, and tumor necrosis factor-alpha from leukocytes, fibroblasts, and endothelial cells from the site of injured tissue.
Cytokines initiate a local response, but also a more systemic acute-phase response with the production of acute-phase proteins from the liver.
Metabolic changes from surgical stress include catabolism of carbohydrates, fat and protein that provide increased energy needed for the production of glucose and acute phase proteins.
The surgical stress response is proportional to the degree of surgical injury.
The type of surgery is associated with the degree of risk of major adverse cardiac events.
Non-cardiac surgeries with less than 1% risk for major adverse cardiac events )MACE) include cataract surgery, and cosmetic surgeries.
Patients with an estimated risk of MACE of less than 1% can proceed to surgery without further testing.
That is assessment of functional capacity in metabolic equivalents is recommended for patients with an estimated cardiac risk of radiation than  or equal to 1%.
Vascular, 7.7%, thoracic, 6.5%, transplant , 6.2%, and general surgery ,3.9%, are associateD with the highest incidence of MACE.
Minimally invasive surgery such as laparoscopic, and endovascular techniques attenuate the cardiovascular risk.
The surgical stress response duration varies: ADH lasts 3 to 5 days postoperatively, cytokine reactions last 48 to 72 hours.

Cardiovascular complications are the most frequent cause of death for patients in the undergoing elective noncardiac surgery.

Initial preoperative evaluation includes detailed history about previous coronary artery disease, symptoms of angina, previous heart failure, aortic stenosis history, hypertension history, and history of peripheral arterial disease.

Anesthesia contributes to perioperative physiologic changes.
There are two major classes of anesthesia available: general and neuroaxial anesthesia.
General anesthesia comprises Hipnosis, analgesia, and muscle relaxation.
General anesthesia leads to multi system physiologic changes particularly during induction and emergence.
The most important effects of generalized seizure are hypotension due to vasodilatation, decreased heart rate, decrease stroke volume, and respiratory impairment due to loss of respiratory muscle tone, reduce lung volume, and airway closure.
The American society of Anesthesia physical status classification system classifies patients according to her overall health status and is independently associated with surgical outcomes in prospective study.
Patients with class 1 stage have a 0.1% risk of cardiac complications and mortality, whereas patients with severe systemic disease that is a constant threat to life which is a ASA class IV has an 80% risk.
Neuraxial anesthesia including spinal epidural techniques create physiological effects due to a blockade of the sympathetic nervous system and unopposed parasympathetic tone.
With neuraxial Induced sympathectomy occurs above the sensory level and causes hypotension and bradycardia.
Patient with hypovolemia or pre-load depending cardiac disease such as aortic stenosis or hypertrophic cardiomyopathy or at significant risk of complications including cardiac arrest and death.
Neuraxial anesthesia has respiratory effects which include dyspnea, reduction and expiratory effort and cough strength and paralysis of the accessory muscles and diaphragm can occur if a high spinal level is achieved.
Neuraxial anesthesia signals to the bladder of both afferent or efferent type, blocks nerve signals and can result in urinary retention.

Functional capacity provides prognostic information, so that patients with good functional status have a low risk of complications.

Preoperative functional impairments will limit patient’s mobility postoperatively.

Cognitive impairment in elderly patients may cause postoperative delirium.

Since delirium is a major contributor to postoperative morbidity and mortality preoperative cognitive assessment can identify patients at risk for delirium and provide alternatives to provoking medications in high-risk patients.

Cardiovascular, pulmonary, and renal disease on more common in elderly patients and contribute to the greater perioperative complication rate in older adults.

Functional status is expressed in metabolic equivalents: 1 MET defined as 3.5 mL of oxygen uptake/kilogram per minute, which is the resting oxygen uptake in the sitting position.

Patients unable to meet a 4-MET demand,which is typical of most normal daily activities, will have increased perioperative cardiac and long-term risk with surgery.

Clinical information include blood pressure measurements in both arms, carotid artery pulsation evaluation, jugular venous pulsations for their quality and contour, the presence of carotid bruits, auscultation of the lungs, precordial palpation and auscultation, abdominal. examination, an examination of the lower extremities for vascular integrity and edema.

Clinical examination for the presence of heart failure or aortic stenosis is important as these factors significantly increase perioperative risk.

ST segment elevations or depressions are associated with increased incidence of perioperative cardiac complications.

A preoperative EKGs recommended for patients with at least one clinical risk factor scheduled to undergo vascular surgery or those patients scheduled to undergo intermediate risk surgery with known cardiovascular disease, perpiheral artery disease, or cerebrovascular disease.

Routine EKGs are not indicated for asymptomatic individuals who are undergoing low risk surgeries.
Preop EKG is a reasonable procedure to perform in severely obese patients who have at least one additional cardiovascular disease risk factor such as diabetes, hypertension, hyperlipidemia, smoking, or poor exercise tolerance.
Preoperative 12-lead ECG defies cardiac rhythm, identifies clinically silent cardiovascular disease such as a prior q wave M.I, and provides a baseline for postoperative comparison.
Stress tests can be considered for patients with elevated risk and poor functional capacity of less than 4MET ‘s.
Routine echocardiographic studies are not recommended in asymptomatic individuals but may be reasonable patients with known valvular disease or decreased left ventricular function.
Guidelines for the preoperative evaluation of patient prior to nine cardiac surgery recommend against routine preoperative cardiac testing in patients  at low cardiac risk, as indicated by a 30 day postoperative incidence of death of myocardial infarction of less than 1%.

In an observational study of patients only going non-cardiac surgery, an elevated aortic valve gradient of 40 mmHg or greater, left ventricular hypertrophy, and any left ventricular systolic dysfunction seen on transthoracic echocardiogram was associated with cardiac events  including:  yocardial infarction, pulmonary edema, ventricular fibrillation, or cardiac arrest, and complete heart block in 7.7% of patients.

Preoperative stress testing is suggested for patients at high risk with three or more cardiac index criteria, with poor functional capacity, scheduled for vascular surgery when such testing will change management.

The cardiac risk of non-cardiac surgeries has improved over time and the risks or stratified into low, intermediate, and elevated cardiac risk.

Many noncardiac surgeries previously  categorized as elevated cardiac risk, are found to be low cardiac risk.

Preoperative cardiovascular stress tests may identify high-risk patients to provide treatments to reduce postoperative major adverse cardiovascular events.

If a major adverse cardiovascular event risk is less than 1%, preoperative stress testing is not required.

Preoperative medical testing is not recommended before low-risk surgery such as cataract, hernia repair and other ambulatory procedures (American Academy of Ophthalomology).

Europe has highest level of ETOH consumption in world and, highest burden of ill health and premature death linked directly to alcohol.

Patients who consume 3–4 drinks per day may have up to 50% higher complication rates, including bleeding, cardiac arrhythmias, impaired wound healing, and intensive care unit admissions when compared with patients who consume 0–2 drinks per day.

Surgical complication rates increase to 200–400% for those who have five or more drinks per day.

Preoperative stress testing is less established for preoperative evaluation in patients with at least one clinical risk factor and poor functional capacity scheduled for intermediate risk surgery when such testing will change management, and in patients with at least one clinical risk factor and good functional capacity when scheduled for vascular surgery.

Pulmonary complication rates are higher in surgeries in the upper abdominal, thoracic, and head and neck areas due to the impact on respiratory mechanics.
Patients should be evaluated for pulmonary disorders, including functional status, assessing for obstructive sleep apnea and hypoventilation syndromes.
Routine chest x-rays were not needed for asymptomatic patients, but  is recommended for patients with known cardio pulmonary disease and older adults who are undergoing abdominal, thoracic, or abdominal aortic anuerysm  surgery.
A preop approve chest x-ray is recommended for patients with severe obesity to assess potentially undiagnosed heart failure, cardiac chamber enlargement, or abnormal pulmonary vasculature suggestive of pulmonary hypertension.
How many function testing is not recommended routinely for preoperative assessment.

Postoperative myocardial infarction usually does not correspond to a region of the most severe coronary stenosis found on preoperative evaluation.

Pre-operative anemia is an important risk factor for perioperative mortality and morbidity.

Preoperative anemia needs to be detected and managed with sufficient time before a major elective surgery to ensure a clinical response.(WHO).

Smoking-related impairment in wound healing decreases and pulmonary function improves within 4–8 weeks of smoking cessation.

Intake of clear fluids up until 2 hours before surgery does not increase gastric content, reduce gastric fluid pH, or increase complication rates.

Preoperative surgical site skin preparation with an alcohol-based agent unless contraindicated is performed.

The perioperative period consists of three phases: preoperative time from decision to undergo an operation until the beginning of the surgical procedure; operative time during the operation and immediate recovery from the recovery room stay; and postoperative time extending from after the patient leaves the recovery room, throughout hospitalization and posthospitalization up to 30 to 60 days.
The risk of adverse cardiac events preoperatively has been separated into low, less than 1%, intermediate 1-5%, and high greater than 5% risk categories.
Low risk procedures include cataract surgery or dermatologic surgeries and are associated with fewer hemodynamic shifts and a smaller surgical stress response.
Specific patient risks are attributable to medical comorbidities that impact the overall risk of a surgical procedure.
Level of risk of major adverse cardiovascular events or death:
Less than 1%
Cataract, cosmetic for plastic surgery.
Approximately 1% risk
Orthopedic, otolaryngology and GU surgery.
3% or greater risk
General of Domino or intraperitoneal surgery and neurosurgery
5% or greater risk
Super inguinal and peripheral vascular surgery, thoracic surgery, and transplant surgery.
Risk I organ system, surgical urgency, surgical risk and patient specific risk factors are necessary inputs for clinical decision making.
The combination of medical and surgical risks for cardiac complications, pulmonary complications, venous thromboembolism, postoperative nausea, vomiting, and delirium should be assessed at all patients.
All patients undergoing surgery should have a risk assessment for  enough thromboembolism and bleeding.
Factors associated with increased thromboembolism include: tissue injury, pro inflammatory states such as cancer, location and duration of the procedure, and immobilization.
Contraindications to non-cardiac surgery include: acute coronary syndrome, acute decompensated heart failure, tachyarrhythmias or bradyarrhythmias associated with hypotension and symptomatic, severe aortic stenosis.

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