October 7, 2015 | Brian Hoyle
“In this study, the use of SSRIs and SNRIs was associated with prolonged intubation and hospitalisation, but not with an increased intubation rate,” clarified lead author Kortney Robinson, MD, Beth Israel Deaconess Medical Center, Boston, Massachusetts, speaking here on October 5. “The mechanism is unclear, but it could include discontinuation syndrome, confounding comorbidities, or possible CPY450 inhibition.”
Discontinued use of SSRIs and SNRIs can cause a host of non-life-threatening symptoms. Dr. Robinson and colleagues examined whether these symptoms influence the rate of intubation following CABG. The researchers searched the Society of Thoracic Surgeons database, which contains nationwide information on adult cardiac, general thoracic, and congenital heart surgery including anesthesiology data. A database search from 2002 to 2013 identified 2,092 patients who underwent CABG. Other elective and emergent cases were excluded.
The team analysed the data using 29 variables that included demographics, comorbidities, length of time in the operating room, and postoperative complications. The primary outcomes were prolonged intubation (considered to be intubation exceeding 24 hours), reintubation, and length of stay in the intensive-care unit.
Preoperatively, 231 patients (11%) were on SSRIs / SNRIs, which was consistent with the national rate of antidepressant use. Of the 2,092 patients, 282 patients (13%) required prolonged intubation, and 100 (4.8%) required reintubation.
Patients medicated with SSRI or SNRI were similar in age to the other patients in the database (65.76 years vs 66.96 years; P = .621), but otherwise had a higher prevalence of comorbid conditions, including preoperative creatinine, hypercholesterolaemia, use of dialysis, hypertension, prior cardiovascular intervention, diabetes, and chronic lung disease.
Univariate analysis revealed an association of SSRI or SNRI use with prolonged intubation compared with non-use (17.9% vs 12.8%; odds ratio [OR] = 1.48, 95% confidence interval [CI], 1.02 to 2.13; P = .037), along with associations of nearly 2 dozen other parameters, but no association between SSRI or SNRI and reintubation (OR = 0.93; 95% CI, 0.48 to 1.82).
Multivariable analysis revealed SSRI or SNRI use as an independent predictor of prolonged intubation (OR = 2.85, 95% CI, 1.1 to 7.41), along with preoperative intra-aortic balloon-pump use (OR = 15.5; 95% CI, 5.8 to 42.3), 2 or more incidences of venous anastomosis (OR = 3.2; 95% CI, 1.3 to 7.9), albumin <3 g/L (OR = 4.7; 95% CI, 1.2 to 18.8), and any postoperative use of fresh frozen plasma (OR = 9.3; 95% CI, 2.6 to 26.1).
In multivariable analysis, SSRI or SNRI use was not associated with reintubation.
SSRI or SNRI use at baseline was associated with intensive-care-unit hospitalisation exceeding 3 days in 31% of patients, as compared with 22% of patients not taking the antidepressant medications (P = .046).
It is unclear why preoperative SSRI / SNRI use is associated with prolonged intubation but not reintubation in patients undergoing urgent CABG. The researchers did not discover any compelling link with prolonged intubation or reintubation after scrutinising the data in patients who developed discontinuation syndrome less than 2 days and more than 2 days after weaning from SSRIs. Cytochrome-450 inhibition and confounding diagnoses are possibilities.
Dr. Robinson speculated that patient-specific conditions, such as length of time of SSRI / SNRI medication and possible consequences of weaning could help determine the decision to discontinue the antidepressant medication preoperatively.
[Presentation title: Preoperative Antidepressant Use: Prolonged Intubationand Reintubation after Cardiac Surgery. Abstract SF18#7]