Preoperative care

Preoperative care is defined as "Care given during the period prior to undergoing surgery when psychological and physical preparations are made according to the special needs of the individual patient. This period spans the time between admission to the hospital to the time the surgery begins."

Components of preoperative care

Cardiac risk reduction

Clinical practice guidelines

Clinical practice guidelines by the American College of Cardiology (ACC) and American Heart Association (AHA) recommend (as summarized by Journal Watch:

• 'Noninvasive stress testing of patients with 3 or more clinical risk factors and poor functional capacity (less than 4 metabolic equivalents METs) who require vascular surgery is reasonable if it will change management"
• "Patients scheduled for low-risk noncardiac surgery should proceed to surgery."
• "Patients with good functional capacity should proceed to surgery."
• "Patients with poor or unknown functional capacity who are scheduled for non-low-risk surgery should be stratified according to the Revised Cardiac Risk Index (Journal Watch Sep 17 1999). Patients with no risk factors should proceed to surgery. For those with one or more risk factors, clinicians are given the option of proceeding with surgery or performing noninvasive stress testing; the decision should be influenced by the type of noncardiac surgery (vascular vs. other), and by whether the clinician believes that noninvasive testing "will change management."
• "For patients with risk factors, clinicians should consider perioperative ß-blockade."
• "The algorithm does not apply to patients who require emergency noncardiac surgery, or to patients with active cardiac problems." Active cardiac conditions are:
  • Unstable coronary syndromes
  • Decompensated heart failure (NYHA functional class IV; worsening or new-onset HF)
  • Significant arrhythmias
  • Severe valvular disease such as severe aortic valve stenosis (mean pressure gradient greater than 40 mm Hg, aortic valve area less than 1.0 cm2, or symptomatic) and symptomatic mitral stenosis

Emerging issues

"Noncardiac surgery should be delayed until at least 30 days (and perhaps even 90 days) after placement of bare-metal coronary stents and 1 year after placement of drug-eluting stents."

Evidence for interventions

Perioperative ß-blockade

Comparison of the POISE, MSPI, and DECREASE trials of
beta-blockers for noncardiac surgery

	POISE trial	MSPI study	DECREASE Study
Total patients	8351	200	173 (all had positive results on dobutamine echocardiography stress test)
Proportion of patients undergoing vascular surgery	42%	41%	100%
Risk of bias according to the Cochrane Collaboration bias scale as assigned by Bangalore et al.	high	low	low
Beta-blocker dose	Intravenous oral metoprolol tartrate followed by metoprolol succinate 200 mg/day	Atenolol 50 to 100 mg/day	Bisoprolol 5 to 10 mg/day
Goal pulse rate	50 to 80 (allowed delayed dosing when pulse 45 to 49)	55 to 65	50 to 60 (started Bisoprolol one week preoperatively)
Significant bradycardia in beta-blocker group	4.2% (requiring treatment or stopping of metoprolol)	0% (requiring stopping of atenolol)	Not reported
Short-term mortality
Beta-blocker group	3.1% (death at two weeks)	4% (in hospital death)	3.4% (within 30 days)
Placebo group	2.3% (death at two weeks)	2% (in hospital death)	17% (within 30 days)
Notes: 1. Metoprolol is the only one of these adrenergic beta-antagonists that is metabolized by cytochrome P-450 2D6 allele. 3-10% of anglos are poor metabolizers of drugs that use the CYP2D6 isoenzyme. As a consequence, metoprolol has more variable effect than bisoprolol. 2. The MSPI study showed reduction in perioperative ischemia and mortality at 6 months to two years

A meta-analysis of randomized controlled trials found that beta-blockers may cause a decrease in myocardial ischemia (number needed to treat = 16) with a lesser increase in non-fatal strokes (number needed to harm [NNH] = 293).

POISE trial

Among the trials in the meta-analysis was the POISE trial. The patient population in the trial, as noted in an earlier methods paper by the authors:

"The POISE trial has recruited >6300 patients in 182 centers in 21 countries. Currently, the patients' mean age is 69 years; 63% are males, 43% have a history of coronary artery disease, 43% have a history of peripheral arterial disease, and 30% have diabetes. Most participants have undergone vascular (42%), intraabdominal (23%), or orthopedic (19%) surgery."

The study drug was controlled-release metoprolol:

"Administration of the study drug at each dosing time, except during the first 6 hours after surgery, requires a patient to have a heart rate ≥50 beats/min and a systolic blood pressure (SBP) ≥100 mm Hg."

"Two to 4 hours before surgery, patients will take 100 mg (ie, half a tablet) of the study drug orally. If the patient heart rate is >80 beats/min and their SBP is ≥100 mm Hg during the first 6 hours after surgery, they will take 100 mg of the study drug orally. Patients who do not receive a dose of the study drug during the first 6 hours after surgery will take 100 mg of the study drug orally at 6 hours after surgery. Starting 12 hours after patients receive their first postoperative study drug dose and daily thereafter for 30 days, they will take 200 mg of the study drug orally. If the patients' heart rate is consistently <45 beats/min or their SBP is <100 mm Hg, caregivers will hold the study drug until the patients' heart rate or SBP recovers and will then administer 100 mg of the study drug orally. If the patients' heart rate is consistently between 45 and 49 beats/min and their SBP is >100 mm Hg, they will delay taking the study drug for 12 hours."

"Patients who are unable to take medications orally will receive the study drug by slow or rapid intravenous infusion every 6 hours until they are able to receive the study drug orally. The slow intravenous infusion consists of 15 mg of the study drug in 25 mL of normal saline infused over a 60-minute period, and patients will have their heart rate and blood pressure checked 10, 30, and 60 minutes after starting the infusion. If the patients' heart rate is <50 beats/min or their SBP is <100 mm Hg, the infusion is stopped and subsequent infusions will consist of 10 mg of the study drug in 25 mL of normal saline infused over a 60-minute period."

"The rapid intravenous infusion will consist of 5 mg of the study drug infused over 2 minutes. Patients will receive the rapid intravenous infusion every 5 minutes, for a total of 15 mg, as long as their vital signs fulfill the standard heart rate and SBP requirements before each dosing."

The results were: Metoprolol reduced risk of the primary composite endpoint of cardiovascular death, nonfatal MI, and nonfatal cardiac arrest at 30 days (hazard ratio: 0.83, P=0.04):

• Metoprolol 5.8%
• Placebo 6.9%

Total mortality at 30 days was increased among patients taking metoprolol (HR: 1.33, P=0.03):

• Metoprolol 3.1%
• Placebo 2.3%

These results suggest that the benefits on the primary outcome were outweighed by adverse effects; however, the POISE trial was unique in using metoprolol in an anglo population although 3-10% of anglos are poor metabolizers of drugs such as metopolol that use the CYP2D6 isoenzyme. This affects many antidepressants, metoprolol and other drugs that use this isoenzyme. More information is available at Entrez Gene.

MSPI trial

In the The Multicenter Study of Perioperative Ischemia Research Group (MSPI), the patients were similar to the POISE study in that about 40% had vascular surgery. The intervention was 50-100 mg of atenolol per day starting on the first postoperative day and continuing for up to 7 days. However, at 6 months there was a trend for more atenolol patients to still be taking beta-blockers (13.8% versus 8.8%).

In the MSPI, atenolol reduced perioperative ischemia.

Regarding mortality, the MSPI study focused its results on mortality at 6 months to two years. In order to compare to the POISE trial, the hospital death rate in the MSPI study was:

• Atenolol 4% (4/99)
• Placebo 2% (2/101)

DECREASE trial

The DECREASE study found benefit by starting bisoprolol 5-10 mg per day at least one week prior to vascular surgery.

Other large trials

Other large randomized controlled trials using metoprolol, bisoprolol, and esmolol have been published and were included in the meta-analysis of Banglore. All patients in these trials were lower risk as manifested in the low risk of complications in the placebo group.

Myocardial revascularization

A randomized controlled trial found that myocardial revascularization was associated with a statistically insignificant 2% absolute reduction in perioperative myocardial infarction among patients undergoing major vascular surgery. The benefit, while still statistically insignificant, was greater for high risk patients.

Pulmonary risk reduction

Clinical practice guidelines by the American College of Physicians state:

1. "All patients undergoing noncardiothoracic surgery should be evaluated for the presence of the following significant risk factors for postoperative pulmonary complications in order to receive pre- and postoperative interventions to reduce pulmonary risk: chronic obstructive pulmonary disease, age older than 60 years, American Society of Anesthesiologists (ASA) class of II or greater, functionally dependent, and congestive heart failure."
2. "Patients undergoing the following procedures are at higher risk for postoperative pulmonary complications and should be evaluated for other concomitant risk factors and receive pre- and postoperative interventions to reduce pulmonary complications: prolonged surgery (>3 hours), abdominal surgery, thoracic surgery, neurosurgery, head and neck surgery, vascular surgery, aortic aneurysm repair, emergency surgery, and general anesthesia."
3. "A low serum albumin level (<35 g/L) is a powerful marker of increased risk for postoperative pulmonary complications and should be measured in all patients who are clinically suspected of having hypoalbuminemia; measurement should be considered in patients with 1 or more risk factors for perioperative pulmonary complications."
4. "All patients who after preoperative evaluation are found to be at higher risk for postoperative pulmonary complications should receive the following postoperative procedures in order to reduce postoperative pulmonary complications: 1) deep breathing exercises or incentive spirometry and 2) selective use of a nasogastric tube (as needed for postoperative nausea or vomiting, inability to tolerate oral intake, or symptomatic abdominal distention)."
5. "Preoperative spirometry and chest radiography should not be used routinely for predicting risk for postoperative pulmonary complications."
6. "The following procedures should not be used solely for reducing postoperative pulmonary complication risk: 1) right-heart catheterization and 2) total parenteral nutrition or total enteral nutrition (for patients who are malnourished or have low serum albumin levels)."

For patients with asthma, more aggressive clinical practice guidelines by the U.S. National Asthma Education and Prevention Program recommend:

• "Patients who have asthma should have an evaluation before surgery that includes a review of symptoms, medication use (particularly the use of oral systemic corticosteroids for longer than 2 weeks in the past 6 months), and measurement of pulmonary function".
• "If possible, attempts should be made to improve lung function preoperatively (FEV1 or peak expiratory flow rate [PEFR]) to either their predicted values or their personal best level. A short course of oral systemic corticosteroids may be necessary to optimize lung function".

Smoking cessation may reduce pulmonary complications according to the results of a randomized controlled trial.

Incentive spirometry does not clearly help reduce pulmonary complications during the perioperative care after coronary artery bypass grafting according to a meta-analysis of randomized controlled trials by the Cochrane Collaboration.

Hepatic risk reduction

The MELD Score can help predict complications of surgery among patients with cirrhosis. The MELD Score may or may not perform better than the Child-Turcotte-Pugh class.

Management of chronic anticoagulation

A systematic review found warfarin does not need interruption during minor procedures. This was confirmed in a cohort study that found that interruption for 5 days or less was generally safe.

For patients needing a low molecular weight heparin bridge, a protocol is available.

Benefits of preoperative medical consultation

The benefits of internal medicine consultation are not clear in an observational study; whereas a pseudorandomized trial found benefit from a hospitalist consultation and a non-randomized trial using historical controls found benefit from geriatrics consultation.

Unnecessary delays in surgery is associated with increased operative risk.

Preoperative methods for surgical risk reduction

A wide range of methods for avoiding surgical errors, either in the operating room or shortly before surgery, are increasingly in use. One method, long used by the choice of individual surgeons, is becoming more of a standard: when, for example, a procedure could be prepared on either the left or right extremity, the surgeon, or even the patient, may write, with an indelible pen, "cut here" on the appropriate site and "do not cut here" on the contralateral extremity, signing both.

Drawing from aviation methods of risk reduction, there are specific points, such as the induction of anesthesia or the entry into a body cavity, when the team stops and goes through a specific checklist of physiological parameters, equipment readiness, etc. In the discipline of crew resource management, one team member is specifically tasked to ask each structured question, and another member to check the matter and give the answer.

See also

• Perioperative care
• Revised Cardiac Risk Index