Perioperative risk is determined by multiple factors including: Invasiveness of the procedure, anticipated triggers of intraoperative stimulation, duration of the operation, expected volume of intraoperative blood loss, type of anesthesia used, and the presence of comorbid conditions. It's crucial to properly prepare patients to endure the surgical and anesthetic stress; thus, rushing through tests and specialist consultations at the last minute is not advisable. The Revised Cardiac Risk Index highlights six key predictors of perioperative complications:
- High-risk surgeries, such as abdominal aortic aneurysm repairs or other major vascular, thoracic, and abdominal operations.
- Ischemic heart disease.
- Congestive heart failure (CHF).
- Cerebrovascular disease.
- Preoperative use of insulin for diabetes mellitus.
- Preoperative serum creatinine levels greater than 2.0 mg/dL, indicating chronic kidney disease.
Additionally, certain active conditions require attention before surgery, including unstable coronary syndromes, significant arrhythmias, severe valvular disease, recent coronary revascularizations (such as stents or percutaneous interventions), pulmonary diseases, cerebrovascular issues, malnutrition, bleeding disorders, and liver disease.
Predictors of complications during the perioperative period include the inherent risk associated with the type of surgery being performed, the patient's age with older individuals at higher risk, gender with males experiencing a higher rate of complications, the American Society of Anesthesiologists (ASA) classification with higher classes indicating greater risk, and the existence of any comorbid conditions that can complicate surgery and recovery.
Morbidity and mortality related to surgery typically categorize into three main areas: cardiac issues, pulmonary complications, or infections at the surgical site.
| Predictor | What qualifies |
|---|---|
| High-risk surgery | Abdominal aortic aneurysm repair, or other major vascular, thoracic, and abdominal operations. |
| Ischemic heart disease | — |
| Congestive heart failure | — |
| Cerebrovascular disease | — |
| Diabetes mellitus | Preoperative use of insulin. |
| Chronic kidney disease | Preoperative serum creatinine greater than 2.0 mg/dL. |
Cardiac Events
Half of the deaths occurring during the perioperative period are attributed to cardiac complications, with the majority happening within the first 72 hours after surgery, peaking at 48 hours. Additionally, myocardial infarctions (MIs) during the perioperative phase carry a mortality rate of up to 50%.
A preoperative cardiac assessment may involve various tests such as electrocardiograms (EKG), angiography, echocardiography, stress testing, and listening to the patient's heart through manual auscultation to identify any previously undetected cardiac irregularities.
Risk factors for cardiac complications primarily include
- Heart disease
- Stents, angiography, percutaneous interventions
- Hypertension
- CHF
- Diabetes
- Other risk factors for cardiac disease (CHF, pulmonary disease, peripheral vascular disease, peripheral edema, exertional symptoms)
- Valvular heart disease
- Intermediate- or high-risk surgery
Patients that ultimately have intraoperative events typically exhibit
- Postoperative myocardial ischemia (which is the 3rd strongest predictor of postoperative morbidity)
- Renal disease
- Anemia
- Preoperative Abnormal EKG
- low albumin levels
Pulmonary Complications
Risk factors for pulmonary complications, which are as prevalent as cardiac complications, include a range of clinical characteristics such as:
- Smoking
- recent upper respiratory infections
- advanced Chronic Obstructive Pulmonary Disease (COPD)
- existing cardiac or pulmonary diseases
- Malignancy
- Pneumonia
- the presence of mediastinal or pulmonary masses
- tracheal deviation
- cardiomegaly.
Pulmonary complications are commonly associated with older age, an ASA classification greater than II, and congestive heart failure (CHF).
Surgical Site Infections
Several risk factors can significantly increase the likelihood of surgical site infections, key among them being smoking, diabetes, obesity, and malnutrition, which is often indicated by low albumin levels. These factors compromise the body's natural ability to heal and fight infection, making the surgical recovery process more challenging. Smoking can impair blood flow, diabetes can affect wound healing processes, obesity can complicate surgery and recovery, and malnutrition can weaken the immune system's response. Together, these factors create a conducive environment for surgical site infections, highlighting the importance of addressing them in the preoperative phase to ensure better surgical outcomes.
