From the Guidelines
All four factors - obesity, hypertension (HTN), diabetes mellitus (DM), and smoking - are linked to post-operative healing and complications, with smoking being particularly detrimental as it causes vasoconstriction, reduces tissue oxygenation, impairs immune function, and delays collagen production, as supported by the most recent study 1.
Post-Operative Complications
Each of these conditions negatively impacts surgical outcomes through different mechanisms.
- Obesity increases wound tension, creates larger dead spaces, and impairs tissue oxygenation, leading to higher rates of surgical site infections and dehiscence.
- Hypertension affects microcirculation and can increase bleeding risk during and after surgery.
- Diabetes mellitus impairs wound healing through multiple pathways including microvascular damage, reduced collagen synthesis, and increased susceptibility to infection due to immune dysfunction.
- Smoking cessation is recommended to reduce postoperative complications, particularly respiratory complications, as stated in the guidelines on enhanced recovery after cardiac surgery under cardiopulmonary bypass or off-pump 1.
Recommendations for Optimal Surgical Outcomes
For optimal surgical outcomes, patients should:
- Achieve good glycemic control (HbA1c <7%)
- Maintain blood pressure below 140/90 mmHg
- Work toward a BMI under 30
- Quit smoking at least 4-8 weeks before elective surgery, as recommended by the guidelines for perioperative care in elective colorectal surgery: enhanced recovery after surgery (ERAS) society recommendations: 2018 1. These interventions significantly reduce post-operative complications including infections, delayed healing, cardiovascular events, and respiratory complications. The most recent and highest quality study 1 supports the importance of smoking cessation in reducing postoperative complications, highlighting the need for patients to quit smoking as soon as possible before cardiac surgery.
From the Research
Post-Operative Healing and Complications
The following factors are linked to post-operative healing and complications:
- Obesity: associated with poor wound healing, hemodynamic instability, intolerance of hypoxia, bleeding, thrombo-embolism, and decreased drug clearance 2, 3
- Hypertension (HTN): associated with incidence of stroke/cerebrovascular accident 4
- Diabetes Mellitus (DM): delays wound healing, associated with postoperative pneumonia, prolonged ventilator dependence, and death 5, 4
- Smoking: associated with readmission, death or serious morbidity, wound complications, and respiratory complications 6
Specific Associations
- Obesity is associated with increased odds of postoperative infection, venous thromboembolism, and renal complications 3
- Diabetes is associated with postoperative pneumonia, prolonged ventilator dependence, and death 4
- Hypertension is associated with incidence of stroke/cerebrovascular accident 4
- Smoking is associated with worse 30-day outcomes, including readmission, death or serious morbidity, wound complications, and respiratory complications 6