Causes of prolonged mechanical ventilation after coronary artery bypass surgery.
OBJECTIVE
To evaluate causes of failure to be extubated (FTE) after coronary artery bypass graft (CABG) surgery.


METHODS
Prospective observational study.


METHODS
Cardiovascular surgical ICU.


METHODS
Four hundred patients undergoing CABG surgery. Following surgery, patients were extubated by a standardized respiratory protocol and were assessed at 8, 24, and 48 h. Patients who could not be extubated at 8 h were designated as FTE, and at 24 and 48 h they were labeled as requiring prolonged mechanical ventilation (PMV) > 24 h and PMV > 48 h, respectively.


RESULTS
One hundred sixty-seven patients (41.75%), 27 patients (6.75%), and 21 (5.25%) patients, respectively, could not be extubated at 8, 24, and 48 h. Depressed level of consciousness was the most common reason for FTE in 58 of 167 patients (34.7%). The main cause of depressed level of consciousness was prolonged sedation due to anesthetic agents (51 patients; 30.5%). Hypoxemia was the most common cause for PMV for > 24 h (15 patients) and PMV > 48 h (13 patients). The causes of hypoxemia were cardiogenic and noncardiogenic pulmonary edema, pneumonia, and "hypoxemia of unknown etiology." Tachypnea due to acid-base disturbances was a reason for FTE and PMV for > 24 h in 27 and 3 patients, respectively. Cardiovascular instability was a rare reason for FTE. Postoperative bleeding was a cause for PMV in 18 patients. Four patients had more than a single reason for FTE at each assessment. Different causes have a variable effect on the duration of mechanical ventilation.


CONCLUSIONS
The causes of PMV are heterogeneous, vary with time, and have a variable impact on the duration of mechanical ventilation required after the patient undergoes CABG surgery.
Yende
Sachin
S
Physician Research Network, Methodist Healthcare University Hospital, Memphis, TN, USA. yende@juno.com
Wunderink
Richard
R
D001026:Coronary Artery Bypass; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000628:therapy*; D011184:Postoperative Period; D011446:Prospective Studies; D012121:Respiration, Artificial; D015300:Ventilator Weaning / Q000706:statistics & numerical data*