Causes of Prolonged Mechanical Ventilation After Coronary Artery Bypass Grafting Surgery

Document Type : Original Article


Background- Coronary artery bypass grafting surgery (CABG) is a commonly performed
procedure. More than 10,000 CABG surgery procedures are performed in Iran annually.
Prolonged mechanical ventilation following CABG surgery is uncommon. Economic factors
have led to a trend for early tracheal extubation after CABG. Fast-track extubation is variously
defined but most agree that it refers to extubation within 8 hours.
Methods-A descriptive observational study was conducted on 196 patients undergoing CABG
surgery. Following surgery, standard weaning protocol was implemented. Patients who failed
to be extubated within 8 hrs were evaluated.
Results- Four patients (2.04%) died within 3 to 12 days. After undergoing surgery, the minimum
duration of mechanical ventilation was 2 hrs, up to a maximum duration of 19 days. 94.3% of
the patients were extubated within 24 hrs, with a mean duration of 9.54 hrs. 5.7% of the
patients were still intubated after 24h. The most common cause of delayed extubation was
physician trend (n=27, 13.8% of patients). Reduced ejection fraction, EKG changes, elderly
age, prolonged CPB, difficult intubation were reasons for this trend. The second most
common cause was excessive postoperative bleeding, which occurred in 13.3% of the patients.
Four percent of the patients were returned to the operating room for re-exploration.
Cardiovascular instability (11.7%), metabolic acidosis (9.7%), prolonged recovery (4.7%),
neurologic problems (2%), poor FVC (4.6%), hypoxemia (1.5%), and acute respiratory
distress syndrome (ARDS) (0.5%) were other reasons.
Conclusion- The incidence of prolonged mechanical ventilation for more than 24h was similar to
that of the STS database.8 We found the most common cause of delayed extubation to be
physician trend. We recommend changing our strategy in these patients. Excessive
postoperative bleeding incidence in our study was slightly higher than that in other studies.
We found the proportion of patients with failure to extubate due to various reasons would vary
from institution to institution, based on differences in patient population and management
strategies(Iranian Heart Journal 2008; 9 (1):47 -54).


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