18.2 Preoperative Pulmonary Risk & Perioperative Medication Management

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19 Chapter 18: Perioperative Medicine & Medical Consultation

18.1 Preoperative Cardiovascular Risk Assessment 18.2 Preoperative Pulmonary Risk & Perioperative Medication Management 18.3 Perioperative Anticoagulation, Bridging & Postoperative Complications

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18.2 Preoperative Pulmonary Risk & Perioperative Medication Management

Key Takeaways Explain This Topic AI

Patient factors such as age, chronic lung disease, smoking, heart failure and functional dependence predict pulmonary complications better than spirometry.

Routine preoperative spirometry and chest radiography are not indicated in the absence of specific clinical indications.

Beta-blockers and statins are continued perioperatively, and beta-blockers should not be started on the day of surgery.

Renin-angiotensin blockers are commonly held on the morning of surgery to reduce intraoperative hypotension.

Lung expansion maneuvers including incentive spirometry and deep breathing reduce postoperative pulmonary complications.

Last updated: August 2026

1. Preoperative Pulmonary Risk Assessment

Postoperative pulmonary complications (PPC)—including atelectasis, pneumonia, prolonged mechanical ventilation (> 48 hours), respiratory failure, and acute bronchospasm—occur in 2% to 7% of all noncardiac surgeries and are major drivers of length of stay and 30-day mortality.

ARISCAT Pulmonary Risk Score

The Assess Respiratory Risk in Surgical Patients in Catalonia (ARISCAT) score is the gold standard for predicting PPCs:

ARISCAT Predictors Risk Points
Age <= 50 years 0 points
Age 51–80 years 3 to 16 points (scaled by age)
Age > 80 years 16 points
Preoperative SpO2 >= 96% 0 points
Preoperative SpO2 91–95% 8 points
Preoperative SpO2 <= 90% 24 points
Respiratory Infection in Past 30 Days 17 points
Preoperative Anemia (Hemoglobin <= 10 g/dL) 11 points
Surgical Incision Site Peripheral: 0 pts; Upper abdominal: 15 pts ; Intrathoracic: 24 pts
Duration of Surgery <= 2 hours: 0 pts; 2 to 3 hours: 16 pts ; > 3 hours: 23 pts
Emergency Procedure 8 points

Risk Categories: Low (< 26 pts, PPC risk ~1.6%), Intermediate (26–44 pts, PPC risk ~13.3%), High (>= 45 pts, PPC risk ~42.1%).

Modifiable Risk Factors & Perioperative Interventions

Smoking Cessation Timing:

Optimal Duration: Complete smoking cessation >= 4 to 8 weeks prior to surgery produces the maximum reduction in postoperative pulmonary complications (improves mucociliary clearance, reduces airway hyperreactivity, and decreases sputum volume).

Cessation < 4 Weeks Prior to Surgery: Historical concerns that quitting smoking immediately before surgery increases sputum and complications have been completely disproven . Smoking cessation at any time (even 24–48 hours pre-op) is beneficial because it eliminates carbon monoxide, reduces carboxyhemoglobin levels from ~5-10% to normal (< 1-2%), and shifts the oxyhemoglobin dissociation curve to the right, improving tissue oxygen delivery.

Pre- and Postoperative Lung Expansion: Incentive spirometry , deep breathing exercises, chest physiotherapy, and early postoperative ambulation significantly reduce postoperative atelectasis and pneumonia.

Postoperative Pain Control: Utilization of regional analgesia (e.g., thoracic epidural analgesia, transversus abdominis plane [TAP] blocks, intercostal blocks) provides superior diaphragmatic motion, allows deep inspiration without splinting, and minimizes systemic opioid-induced respiratory depression.

2. Perioperative Medication Management

Managing outpatient medications across the perioperative transition requires precise balancing of the risks of drug withdrawal against the risks of intraoperative hemodynamic instability, bleeding, and metabolic decompensation.

Comprehensive Medication Management Framework

Drug Class Specific Agents Perioperative Management Strategy & Rationale

Beta-Blockers Metoprolol, Atenolol, Carvedilol, Bisoprolol CONTINUE on the morning of surgery with a sip of water. Prevents sympathetic surge, rebound tachycardia, hypertension, and ischemia.

Calcium Channel Blockers Amlodipine, Diltiazem, Verapamil CONTINUE throughout the perioperative period to maintain blood pressure and rate control.

Central Alpha-2 Agonists Clonidine CONTINUE . Abrupt cessation can precipitate severe, life-threatening rebound hypertensive crisis . If oral intake is restricted postoperatively, convert to transdermal clonidine patch.

ACE Inhibitors & ARBs Lisinopril, Enalapril, Losartan, Valsartan HOLD 24 hours prior to surgery (omit morning dose). Blocking the renin-angiotensin-aldosterone system under general anesthesia causes severe, refractory intraoperative vasodilation and hypotension. Resume 24–48 hours postoperatively once the patient is euvolemic and hemodynamically stable.

Diuretics Furosemide, Torsemide, Hydrochlorothiazide, Chlorthalidone HOLD on the morning of surgery . Prevents intraoperative hypovolemia, hypotension, and electrolyte disturbances (hypokalemia). Exception: Continue low doses in patients with symptomatic congestive heart failure and active fluid overload.

SGLT2 Inhibitors Empagliflozin, Dapagliflozin, Canagliflozin HOLD 3 to 4 days prior to surgery (3 days for Empagliflozin and Dapagliflozin; 4 days for Canagliflozin). Prevents life-threatening Euglycemic Diabetic Ketoacidosis (euDKA) , which can develop during surgical fasting and stress despite normal blood glucose levels.

GLP-1 Receptor Agonists Semaglutide, Dulaglutide, Liraglutide, Tirzepatide HOLD weekly formulations 1 week prior to surgery; HOLD daily formulations on the morning of surgery (per American Society of Anesthesiologists consensus). GLP-1 RAs delay gastric emptying, leading to retained gastric contents despite standard NPO fasting and increasing the risk of pulmonary aspiration during endotracheal intubation.

Metformin Metformin HOLD on the day of surgery (and 48 hours prior if intravenous iodinated radiocontrast is administered). Prevents lactic acidosis in the setting of perioperative renal hypoperfusion or acute kidney injury.

Sulfonylureas & Meglitinides Glipizide, Glimepiride, Glyburide, Repaglinide HOLD on the morning of surgery while the patient is NPO to prevent hypoglycemia.

Statins Atorvastatin, Rosuvastatin, Simvastatin CONTINUE throughout the perioperative period. Pleiotropic anti-inflammatory and plaque-stabilizing effects reduce perioperative cardiovascular events.

Aspirin (Secondary Prevention) Aspirin 81 mg daily CONTINUE throughout the perioperative period for secondary prevention (established CAD, prior stroke/TIA, or coronary stents), UNLESS undergoing closed-space high-bleeding-risk surgery (intracranial neurosurgery, spinal canal procedures, posterior eye chamber surgery).

P2Y12 Inhibitors Clopidogrel, Ticagrelor, Prasugrel HOLD 5 days prior for Clopidogrel and Ticagrelor; HOLD 7 days prior for Prasugrel . Continue Aspirin monotherapy. If coronary stents are present, strictly respect mandatory minimum delay times before elective surgery.

Perioperative Insulin Management Protocols

Night Before Surgery: Administer 75% to 80% (20–25% reduction) of the usual evening long-acting basal insulin (Glargine, Detemir, Degludec) or NPH dose.

Morning of Surgery: Administer 70% to 80% of the usual morning basal insulin or NPH dose. HOLD all rapid-acting or short-acting prandial insulin (Lispro, Aspart, Regular) while the patient is NPO.

Intraoperative & Inpatient Glucose Targets: Check point-of-care capillary blood glucose every 2 to 4 hours while NPO. Maintain blood glucose within the target range of 140 to 180 mg/dL (7.8 to 10.0 mmol/L) using subcutaneous short-acting insulin correction scales or IV regular insulin infusions. Avoid tight glycemic control (< 110 mg/dL) due to documented excess mortality from severe hypoglycemia (NICE-SUGAR trial).

Coronary Stent Timing Before Elective Noncardiac Surgery

Bare-Metal Stents (BMS): Elective noncardiac surgery MUST be delayed for at least 30 days following BMS implantation to allow adequate endothelialization and prevent catastrophic stent thrombosis.

Drug-Eluting Stents (DES): Elective noncardiac surgery MUST be delayed for at least 6 months (180 days) following DES implantation.

Exception: If the surgical procedure is urgent and the risk of delaying surgery outweighs the risk of stent thrombosis, surgery may be considered after a minimum of 3 months (90 days) , provided DAPT is continued as long as feasible and aspirin is maintained throughout the perioperative period.

Dual Antiplatelet Therapy (DAPT) Management: Hold the P2Y12 inhibitor (Clopidogrel/Ticagrelor for 5 days; Prasugrel for 7 days) while continuing Aspirin uninterrupted. Resume the P2Y12 inhibitor loading dose postoperatively as soon as hemostasis allows.