Preoperative Evaluation

Question 1

What are the goals of the preoperative evaluation?

Answer 1

The preoperative evaluation consists of gathering necessary information about the patient and formulating an appropriate anesthetic plan. The overall objective is to make sure the patient is medically optimized when time permits to limit perioperative risks

Question 2

Discuss what needs to happen before commencing anesthetic care?

Answer 2

Before the delivery of anesthetic care, the following should occur:
-Review of medical record and determination of American Society of Anesthesiologists (ASA) status

• Physical examination, which at a minimum includes an evaluation of the airway, heart, and lungs
• Discuss medical conditions, allergies, previous anesthetics, family history of problems with anesthesia, and NPO status
• Review available pertinent medical records and order additional tests and consults if necessary

Question 3

Why is it important to ask about previous anesthetic complications?

Answer 3

patient’s previous anesthetic experience may provide valuable information, which could change anesthetic management.

• For example, patients who have had a family history of malignant hyperthermia or fevers under anesthesia should receive a nontriggering anesthetic (see Chapter 45 for more information).
• Patients with history of postoperative nausea and vomiting (PONV) may benefit from preoperative medications, regional anesthesia and/or a total intravenous anesthetic technique.
• Also, patients with known difficult airways are often informed of this after receiving prior anesthetics and may recall the need to tell future clinicians when prompted.

Question 4

What are the features of informed consent?

Answer 4

The person giving consent must have the capacity to make an informed decision.
-The patient must be informed on the risks, benefits and options, in language they clearly understand.

• Translators should be offered and all attempts to respect cultural differences should be made.
• Lastly, the patient must be allowed to make a voluntary decision without coercion.

Question 5

How does one manage a patient with a DNR order presenting for surgery?

Answer 5

Patients with do not resuscitate (DNR) orders require a discussion before surgery, including which interventions and resuscitation options may be used during surgery. Because the administration of anesthesia involves interventions potentially viewed as resuscitative efforts (e.g., endotracheal intubation, blood product administration, vasopressor administration), it is imperative to clarify what interventions are available to the clinician. Many times DNR resuscitative orders are placed on temporary hold during the perioperative period; however patients should not be forced to rescind these orders. This is best accomplished with a discussion involving the patient, family members, and/or legal representatives.

Question 6

6. Discuss the physical status classification of the American Society of Anesthesiologists.

Answer 6

The ASA classification system is a 1 to 6 grading system quantitating a patient’s physical status immediately before a procedure. It is does not predict operative risk.
• Class 1: A normal healthy patient (e.g., a healthy, nonsmoker)
• Class 2: A patient with mild systemic disease (e.g., controlled hypertension, smoker, obesity, etc.)
• Class 3: A patient with severe systemic disease (e.g., compensated congested heart failure [CHF], chronic obstructive pulmonary disease [COPD], morbid obesity)
• Class 4: A patient with severe systemic disease that is a constant threat to life (e.g., uncompensated CHF or COPD)
• Class 5: A moribund patient who is not expected to survive without the operation (e.g., severe head injury, massive trauma)
• Class 6: A declared brain-dead patient whose organs are being removed for donor purposes
The addition of “E” denotes an Emergency surgery. An emergency is defined as existing when any delay in
treatment would significantly increase the threat of death and/or loss of body part.

Question 7

What are clinical risk calculators?

Answer 7

Clinical calculators attempt to quantify perioperative risk by entering patient and surgery specific information. Two commonly used risk calculators are the RCRI and the American College of Surgeons NSQIP risk prediction calculators. The RCRI calculator is a series of Yes/No questions which include the following: (1) high-risk surgery,
(2) history of ischemic heart disease, (3) history of CHF, (4) history of cerebrovascular disease, (5) preoperative treatment with insulin, (6) preoperative creatinine greater than 2 mg/dL. Answering “Yes” to any questions
1 to 6 increases the risk of a major cardiac event during surgery.
The NSQIP risk model identifies five underlying factors as predictors of perioperative myocardial infarction or cardiac arrest, including: (1) type of surgery, (2) dependent functional status, (3) abnormal creatinine,
(4) ASA functional status, and (5) increased age. A calculator was developed for this model which includes approximately 20 questions and produces a composite risk score.

Question 8

What are the preoperative fasting (NPO) guidelines for healthy patients undergoing elective procedures?

Answer 8

• Clear liquids—2 hours
• Breast milk—4 hours
• Infant formula, nonhuman milk, nonclear liquids—6 hours
• Light meal—6 hours
• Full meal, fried or fat-rich foods—6 to 8 hours

Question 9

Are NPO guidelines always be followed?

Answer 9

Emergency cases should proceed regardless of NPO status. For urgent cases, a discussion regarding the risk of waiting versus the risk of proceeding to surgery with a full stomach should occur. For nonemergent, nonurgent elective cases, it is considered best practice to honor the current NPO guidelines.

Question 10

What is ERAS?

Answer 10

ERAS stands for enhanced recovery after surgery. It is a protocol-driven multimodal perioperative treatment plan designed to achieve early recovery after surgical procedures. Key components of ERAS protocols include preoperative counselling, optimization of nutrition, standardized analgesic and anesthetic regimens, minimization of opioids, and early mobilization.

Question 11

How is ERAS changing traditional NPO guidelines?

Answer 11

ERAS’ focus on preoperative optimization of nutrition is causing anesthesiologists to reexamine the practice of prolonged NPO time periods before surgery. Although no clear guidelines have been presented, many institutions are liberalizing the time during which patients may have clear liquids in the preoperative setting. Some even encourage the use of carbohydrate drinks preoperatively to enhance recovery.

Question 12

What is the perioperative surgical home (PSH)?

Answer 12

The PSH model of care is an integrated interdisciplinary team approach to perioperative care. The goal is to deliver more efficient care, and to decrease resource utilization and complications, thus resulting in better outcomes.

Question 13

What routine preoperative tests which should be done before surgery?

Answer 13

Routine laboratory testing of asymptomatic patients is not recommended. Selective laboratory tests should be obtained to guide decision making in perioperative period based on a patients’ history, physical examination, and planned procedure.

Question 14

Should one obtain a baseline hemoglobin? Coagulation studies? Electrolytes?

Answer 14

• Blood typing/crossing should be done in patients where there is a reasonable likelihood of needing a transfusion. This can be secondary to preexisting anemia or a procedure with high expected blood loss.
• Routine hemoglobin testing is not indicated. Considerations for testing should include the invasiveness of procedure, coexisting diseases, extremes of age, dyspnea, history of anemia or bleeding, and medication history.
• Coagulation studies should be considered for patients with history of a bleeding diathesis, liver or kidney dysfunction, or in those who are on anticoagulant medications.
• Routine serum chemistry testing is not indicated unless the patient’s history (e.g., kidney disease/diuretic use) would increase the likelihood of an abnormal test value. Also it may be considered in high-risk patients to better quantify preoperative risk as serum creatinine is sometimes used in risk calculators.

Question 15

Should a pregnancy test be performed before all procedures?

Answer 15

All female patients of reproductive age should at least be offered a pregnancy test before receiving an anesthetic. Many institutions have policies in place to test all females of reproductive age. In general, elective procedures are deferred until after delivery. The second trimester is regarded as the safest time for procedures because organogenesis has occurred and the risk of spontaneous abortion or preterm labor is lower.
Note that pregnant women should never be denied indicated procedures regardless of trimester and none of the commonly used anesthetic agents have been definitively shown to be teratogenic. If the decision to operate on a woman with a viable aged fetus (usually 24 weeks) is made, then plans for expedient delivery and/or cesarean section, along with subsequent care of the infant and mother, must be in place.

Question 16

At what age should patients have an electrocardiogram?

Answer 16

The 2014 ACC/AHA guideline gives a IIa recommendation that preoperative resting 12-lead electrocardiogram is reasonable for patients with known coronary artery disease, significant arrhythmia, peripheral arterial disease, cerebrovascular disease, or other significant structural heart disease. This recommendation is excepted for those undergoing low-risk surgery.
In general, if a patient is having an invasive procedure, where large amounts of blood loss are expected, where postoperative organ dysfunction may occur, and having baseline laboratory tests would be helpful, or if the formal quantification of preoperative risk is desired (see later), then preoperative laboratory tests are reasonable. The routine ordering of tests on all patients regardless of clinical status is not appropriate.

Question 17

What is a MET? Why is it important?

Answer 17

MET is an abbreviation for metabolic equivalent, with one MET approximating the amount of oxygen consumed in resting basal state (about 3.5 mL/kg/min). The 2014 ACC/AHA guidelines, on preoperative cardiac testing, recommend no further testing for patients who can perform more than 4 METS (e.g., climb two flights of stairs, walk four blocks). In general, patients who can perform more than 4 METS have a low risk for postoperative complications, whereas patients with less functional capacity have a higher risk for postoperative complications.

Question 18

Describe the recommended approach to the perioperative cardiac evaluation of patients scheduled for noncardiac surgery.

Answer 18

The 2014 ACC/AHA guideline presents an algorithmic approach to perioperative cardiac evaluation in patients undergoing noncardiac surgery. It requires an assessment of a patient’s cardiac risks before surgery, taking into account the urgency of surgery, the presence of active cardiac conditions, the invasiveness of the planned surgery, the patient’s functional status, and the presence of clinical risk factors for ischemic heart disease. Taken together, this algorithm underscores the importance of a history focused on cardiac issues for all surgical patients

Question 19

What are the named clinical risk factors in the 2014 ACC/AHA guideline on Perioperative Cardiovascular Evaluation and Management of Patients Undergoing Noncardiac Surgery?

Answer 19

• Coronary artery disease
• Cerebrovascular disease
• Heart failure
• Cardiomyopathy
• Valvular heart disease
• Arrhythmias and conduction disorders
• Pulmonary vascular disease
• Adult congenital heart disease

Question 20

Summarizethe2016AHA/ACC guidelines for patients presenting for cardiac stent placement.

Answer 20

Patients who are status post (s/p) cardiac stent placement are frequently on oral antithrombotic agents to prevent stent thrombosis and subsequent major adverse cardiovascular events (MACE). Of note, the risk of MACE is heightened in the perioperative period, thus making the cessation of antithrombotic agents risky. When a patient with recent stent placement presents for surgery, it is important to know what type of stent was placed, as well as the timing of the intervention. The common cardiac interventions include balloon angioplasty, coronary stenting with either a BMS or DES, and/or coronary artery bypass grafting surgery. The summary of these guidelines are as follows:

• Elective noncardiac surgery should be delayed 30 days after BMS implantation and optimally 6 months after DES implantation.
• For patients treated with dual antiplatelet therapy (DAPT) after coronary stent implantation, undergoing a surgical procedure that mandates the discontinuation of P2Y12 inhibitor therapy, it is recommended that aspirin be continued if possible and the P2Y12 platelet receptor inhibitor be restarted as soon as possible after surgery.
• When noncardiac surgery is required in patients currently taking a P2Y12 inhibitor, a consensus decision among treating clinicians regarding the relative risks of surgery and continuation/discontinuation of antiplatelet therapy is advised.
• Elective noncardiac surgery may be considered 3 months after DES implantation in patients in whom P2Y12 inhibitor therapy will need to be discontinued, if the risk of further delay of surgery is greater than the expected risks of stent thrombosis.
• Elective noncardiac surgery should not be performed within 30 days of BMS implantation or within 3 months of DES implantation if it requires the discontinuation of DAPT.
• Patients with DES for more than 6 months may stop DAPT and proceed with surgery.

Question 21

21. What are the preoperative considerations for patients with pacemakers and/or AICDs?

Answer 21

A patient with a pacemaker (PM) and/or implantable cardioverter-defibrillator (ICD) requires preoperative consultation involving cardiology, the institutional ICD team, or the manufacturer, in addition to the anesthesiologist and surgeon. Important details of the assessment include type of device, manufacturer, model number, settings, current function, and response to magnet placement over the device.
If the patient is pacer dependent and electromagnetic interference is anticipated (e.g., electrosurgery unit), the PM or combination PM/ICD should be reprogrammed to an asynchronous mode to avoid the possibility of bradycardia and/or asystole. ICDs should have antitachycardia therapy suspended before EMI.

Magnets can be applied over the PM or ICD to temporarily reprogram the device, and the clinician should confirm a specific device’s response to magnet placement before surgery. When a magnet is applied, most PMs will reprogram to an ansyncronous pacing mode, and most ICDs will deactivate antitachycardia therapy.

Question 22

Why is it important to inquire about preoperative steroid use?

Answer 22

Patients on chronic steroid therapy are at risk for adrenal insufficiency, which can present as unexplained hypotension in the perioperative period. These patients may need to be treated with stress dose steroids. In general, patients on steroids for less than 3 weeks or receiving an AM dose of 5 mg prednisone (or equivalence) daily do not
need supplemental therapy.

Question 23

How are beta blockers managed in high-risk patients perioperatively?

Answer 23

Beta blockers should be continued in patients undergoing surgery who are currently taking them. Initiating beta blockers perioperatively in patients who are at high risk for myocardial ischemia or who have multiple cardiac risk factors is occasionally done as well.

Question 24

What is the concern for patients on an ACEi and ARBs?

Answer 24

Patients on ACEi and ARBs are prone to experiencing intraoperative hypotension. For this reason, many institutions will instruct patients to refrain from taking these drugs on the day of surgery. However, it is noteworthy that these medications have been shown to be beneficial, and definitive guidelines on stopping these drugs is currently lacking. It is important to be aware of the risk of periprocedural hypotension and to be prepared to treat it in patients
who have taken these medications.

Question 25

Discuss the preoperative considerations for patients taking antithrombotic agents.

Answer 25

Antithrombotic drugs can be divided into two main classes: antiplatelet and anticoagulant. Antiplatelet drugs include cyclooxygenase inhibitors, adenosine diphosphate receptor inhibitors, phosphodiesterase inhibitors, and glycoprotein IIb-IIIa inhibitors. Anticoagulant drugs include antithrombin III activators, heparin-like and direct factor Xa inhibitors, direct thrombin inhibitors, and vitamin K antagonists.
Antithrombotic drugs have varied durations of action depending on their individual half-lives. Generally there are not specific recommendations regarding when to stop each drug before surgery. The American Society of Regional Anesthesia does have guidelines for stopping antithrombotic medications before neuraxial procedures, and these represent a more conservative approach than what is generally needed for surgery. It is important to remember that thrombotic events are a major source of perioperative morbidity and mortality, and that the management of these medications perioperatively is an important decision that should occur after careful consideration of the risks
and benefits among all clinicians involved in the patient’s care.

Question 26

What are the considerations for anticoagulated patients who present for urgent or emergent procedures? What agents are able to be emergently reversed?

Answer 26

Clinicians occasionally need to reverse a patient’s anticoagulant therapy for urgent or emergency procedures. Reversal of anticoagulation should be reserved for anticipated severe life-threatening bleeding, as once a patient’s anticoagulation is reversed, the risk of perioperative thrombotic complications increases. Three common agents that can be rapidly reversed are:
1) Warfarin is a vitamin K antagonist with a prolonged clinical effect. With warfarin reversal, timing is
important. For semi-urgent reversal, warfarin should be held and vitamin K given. Immediate reversal can
be facilitated with prothrombin complex concentrates (PCCs) or plasma products (e.g., fresh frozen plasma).

2) Dabigatran functions as an oral direct thrombin inhibitor, and can be reversed with idarucizumab.

3) Rivaroxaban, apixaban, and edoxaban function as oral direct factor Xa inhibitors, and can be reversed with
andexanet alfa. PCCs have been used to reverse direct factor Xa inhibitors for life-threatening bleeding, but supporting evidence is lacking.

Question 27

How would perioperative anticoagulant management occur in a high-risk patient on warfarin therapy who presents for an elective procedure, whose surgeon is requesting it reversed using low-molecular-weight heparin (LMWH)?

Answer 27

As an example, warfarin could be stopped 5 days before the procedure and bridging therapy could then commence with LMWH. The patient could be given a therapeutic dose of LMWH starting the first day after warfarin was held.
It would then be stopped 24 hours before surgery. On postoperative day 1, warfarin would be resumed and LMWH resumed for 48 to 72 hours. This approach would enable the patient to experience a brief window during which their risk of bleeding is reduced, while minimizing the time that they are at elevated risk for a experiencing a thrombotic event. Note, these types of decisions regarding anticoagulation management usually require multidisciplinary input.

Question 28

How are herbal medications and supplements managed in the perioperative period?

Answer 28

Traditionally, all herbal medications and supplements are held for a week before surgery. Note that these products are not regulated by the US Food and Drug Administration, and exact doses, effects, and drug-interactions are not well known. Some clinically relevant (and commonly tested) side effects of herbal supplements include:
• Increased bleeding seen with ginger, gingko, and garlic, via interference with platelet function
• Induction of P450 system by St. John’s wort, potentially increasing metabolism (decreasing efficacy) of a
variety of medications
In general, procedures should not be delayed if a patient presents on herbal medications.

Question 29

Discuss the preoperative considerations for chronic pain patients, including the management of those patients taking methadone, buprenorphine, and Suboxone.

Answer 29

Opioid dependent patients, in general, should take their daily maintenance dose of opioids before surgery. Patients with transdermal fentanyl patches should continue wearing these throughout the perioperative period when feasible, with special consideration taken to avoid damaging or applying heat to the patches during the perioperative period. Patients taking methadone or buprenorphine, typically as maintenance therapy for opioid addiction, should take these medications before surgery. Buprenorphine is a partial mu opioid receptor agonist/antagonist at the kappa opioid receptor, thus potentially reducing the efficacy of other opioids. Of note, in addition to instructing patients to continue their buprenorphine, clinicians should maximize the use of nonopioids for analgesia when appropriate. Also perioperative use of opioid antagonists, such as naloxone and naltrexone, can precipitate withdrawal symptoms in opioid dependent patients, and should be avoided in the perioperative period.
For patients taking combination buprenorphine and naloxone (trade name Suboxone) for opioid dependency, there is not a clear perioperative management strategy. Providers should coordinate with the patient’s prescribing clinician. For minor procedures, with low levels of postoperative pain, frequently the patient may continue Suboxone and the perioperative team needs to be aware that the patient may have increased analgesic requirements.
For procedures with expected high levels of postoperative pain, the Suboxone will often be discontinued preoperatively and resumed after the procedure, so as not to diminish the effects of opioid analgesics during this time period.

Question 30

Discuss the benefits of perioperative smoking cessation.

Answer 30

According to American College of Surgeons, quitting smoking 4 to 6 weeks before an operation, and staying smoke-free 4 weeks after, can decrease the rate of wound complications by up to 50%. The ASA recommends patients abstain from smoking for as long as possible before and after surgery, but even quitting for only a brief period is still beneficial. Of note, there is no data to support the common belief that quitting too close could have negative effects by increasing coughing or airway irritability.

Question 31

What are the risk factors for postoperative pulmonary complications?

Answer 31

COPD, age over 50 years, CHF, current cigarette use, pulmonary hypertension, poor general health status, low preoperative oxygen saturation, emergency surgery, upper abdominal and thoracic surgery, and current respiratory infections.

Question 32

32. Are there ways to predict postoperative respiratory complications?

Answer 32

A few different risk calculators can be used to quantify pulmonary risk and may be useful for high-risk patients. These include the ARISCAT risk index (from the Assess Risk in Surgical Patients in Catalonia Trial, 2010), the Arozullah respiratory failure index, the Gupta calculator for postoperative respiratory failure, and the Gupta calculator for postoperative pneumonia.

Question 33

List the goals of premedication.

Answer 33

Premedications are given before procedure to minimize the likelihood of nausea, pain, hemodynamic instability, anxiety, aspiration and pruritus, and to decrease postoperative narcotic requirements. Commonly used premedications and their doses are listed in Table 2.1.
Factors to consider regarding premedication include:
• Patient age, allergies, and physical status
• Preprocedural levels of anxiety and pain
• History of PONV or motion sickness
• History of alcohol, and/or drug abuse
• Full stomach and risk of aspiration
• Suspected postoperative pain levels

Question 34

34. Is it safe to give oral (PO) medications before surgery

Answer 34

Yes, but with some notable exceptions. Patients who are at high risk for aspiration (e.g., bowel obstruction) or who are having specific gastrointestinal procedures (e.g., gastric bypass) generally should not receive PO medications before surgery. Apart from these situations, administering oral medications, with minimal water preoperatively,
is usually acceptable. Most patients should continue their prescribed medications on the day of surgery,
including their pain medications.