Preexisting medical conditions should be controlled or stabilized before surgery. Many of the complications associated with these conditions may be prevented by thoughtful administration of standard medications.

1. HTN. Untreated HTN can cause end-organ damage. Acute treatment of chronic HTN may be indicated in the patient with systolic blood pressures greater than 20% of their baseline. If HTN persists despite treatment or if the blood pressure is greater than 180/110 mm Hg, elective surgery should be postponed until the blood pressure is better controlled. Angiotensin-converting enzyme inhibitors and angiotensin receptor blocking agents may cause refractory vasoplegia and should be held the night before or on the day of surgery. β-blockers, calcium channel blockers, and clonidine may be continued perioperatively.
2. Coronary artery disease. In patients with a recent history of percutaneous coronary intervention or coronary artery bypass grafting on dual antiplatelet therapy (DAPT), careful consideration must be given to medication management and timing of surgical procedure. See the 2016 ACC/AHA Guideline Focused Update on Duration of DAPT Therapy in Patients With Coronary Artery Disease for comprehensive guidelines. Chapter 3 further outlines the stepwise approach to preoperative evaluation in patients with CAD.

   Individuals on long-term β-blocker therapy should continue their medication in the perioperative period. Postoperative dose modification in the setting of bradycardia or hypotension is appropriate. Current literature does not support initiating prophylactic β-blockade immediately prior to or on the day of surgery, as this has been associated with increased all-cause mortality. Detailed recommendations for perioperative beta-blocker administration is further outlined in the 2014 AHA/ACC Guideline on Perioperative Cardiovascular Evaluation and Management of Patients Undergoing Noncardiac Surgery.

   With regard to aspirin, new evidence reveals that the risks may outweigh the benefits for primary prevention. Guidelines at MGH state that aspirin (81-325 mg) be continued up to and including the day of surgery, except in the case of intracranial neurosurgical procedures, intramedullary spine surgery, surgery of the middle ear or posterior eye, and possibly prostate surgery. Complete reversal of aspirin effects requires 7 to 10 days for new platelet synthesis. Discontinuing aspirin in a patient receiving aspirin for secondary prophylaxis necessitates an explicit discussion with the patient’s primary care physician, cardiologist, or vascular physician. The decision should weight the cardiovascular risks of stopping aspirin versus the risk of bleeding from the surgery.

3. Anticoagulation therapy. Depending on the indication for the anticoagulation, a patient on warfarin may need to be bridged with low-molecular-weight heparin or unfractionated heparin regimens prior to surgery. This decision should be made with the surgeon and physician prescribing the anticoagulation.
4. NSAIDs. The modest inhibition of platelet function caused by NSAIDs does not increase bleeding risk nor does it increase the risk of hematoma associated with spinal or epidural anesthesia. Celecoxib does not affect platelet function and therefore may be continued perioperatively in those who take it chronically. Some surgeons still hesitate to continue NSAIDs given data suggesting deleterious effects on bone healing. Given the oppositional literature, a discussion with the surgeon regarding NSAID use is justified. As part of expedited recovery after surgery (ERAS) protocols, NSAIDs are often given as part of a preoperative cocktail. Caution should be taken with patients who have severe coronary disease, peptic ulcer disease, HTN, renal disease, and asthma.
5. Opioid tolerance. Usual doses of opioids should be continued in the perioperative period to avoid withdrawal. Multimodal analgesia and regional anesthetics should be pursued as determined by patients and surgical factors. A patient taking methadone should continue maintenance dosing through the day of surgery. A patient taking Suboxone should have a plan formulated by their prescribing physician, surgeon, and anesthesiologist. Guidelines at MGH recommend patients on Suboxone ≤8 mg/d (4 mg BID) continue their baseline regimen throughout the perioperative period. Higher daily dosage may require preoperative titration to optimize surgical pain management. For inpatient procedures, an Addictions Consult Team should be consulted to assist in the postoperative titration of Suboxone.
6. Asthma. A patient with moderate to severe asthma may require treatment with albuterol or ipratropium via metered dose inhaler immediately prior to airway instrumentation. A wheezing patient should be referred to a pulmonologist or internist for optimization and symptom control before surgery. All asthma medications—inhaled and oral—should be continued perioperatively.
7. Diabetes mellitus. A diabetic patient may present with hyperglycemia or hypoglycemia. A blood glucose level should be obtained by finger stick preoperatively and abnormal levels addressed (see Chapter 7). Severe and acute hyperglycemia can lead to a hyperosmolar state that can result in impaired enzyme function, diabetic ketoacidosis, or a hyperosmolar hyperglycemic nonketotic state. Oral hypoglycemic agents and short-acting insulin should all be held on the day of surgery. Basal insulin should be continued, albeit many recommend a reduction of 20% to 50%, and blood glucose levels closely monitored.
8. High aspiration risk. Guidelines to reduce the risk of pulmonary aspiration have been published by the ASA and include preoperative assessment risk factors, nil per os (NPO) status, and pharmacological agent recommendations. These precautions should be implemented for patients at high risk of aspiration, like those with a hiatal hernia, difficult airway, ileus, obesity, poorly controlled diabetes, depressed sensorium, pregnancy, and acute trauma. The following medications can be administered to decrease gastric acid and/or decrease gastric volume: H₂ antagonists such as cimetidine, famotidine, and ranitidine reduce the volume and acidity of gastric secretions. Cimetidine inhibits the CYP P450 system and prolongs the elimination of many drugs, including theophylline, diazepam, propranolol, and lidocaine, potentially increasing the toxicity of these agents. Ranitidine has recently been withdrawn from the market due to FDA concerns over contamination. Proton-pump inhibitors are highly effective in reducing acid production but do not work quickly enough to be used in the immediate preoperative period; the greatest benefit is seen in patients on long term therapy. Nonparticulate antacids, such as sodium citrate and citric acid (Bicitra) raise gastric pH. Metoclopramide enhances gastric emptying by increasing lower esophageal sphincter tone and simultaneously relaxing the pylorus. As with all dopamine antagonists, it may produce dystonia or other extrapyramidal effects. Metoclopramide is contraindicated in suspected bowel obstruction due to increased risk of perforation.
9. Other medications. In general, anticonvulsants, antiarrhythmics, steroids, and hormonal supplements may be continued through the perioperative period. Vitamins and herbal supplements should be discontinued a minimum of 7 days prior to surgery.