J. N. Byrd1, I. Nassour3, H. Zhu4, D. Xiang1, S. Luk2, J. Minei2, M. Choti1 2University Of Texas Southwestern Medical Center,Division Of Burn/Trauma/Critical Care, Department Of Surgery,Dallas, TX, USA 3University Of Texas Southwestern Medical Center,Department Of Surgery,Dallas, TX, USA 4University Of Texas Southwestern Medical Center,Department Of Clinical Science,Dallas, TX, USA 1University Of Texas Southwestern Medical Center,Dallas, TX, USA
Introduction:
Rates of conversion from laparoscopic to open cholecystectomy in the U.S. have been reported to be 5 to 10%. Conversion is an intraoperative decision made in the interest of patient safety. There is no consensus about the predictors of conversion for laparoscopic cholecystectomy. This study aims to identify preoperative factors that are predictive of conversion at a large, safety-net hospital.
Methods:
The data for all patients who underwent laparoscopic and converted cholecystectomies from 2007 to 2015 were retrospectively reviewed in the electronic medical records of a public, teaching hospital. We excluded cholecystectomies performed as part of a cancer operation or secondary to trauma. Baseline demographic and clinical factors were summarized by medians and interquartile ranges for continuous variables and by counts and percentages for discrete variables. Univariate and multivariate logistic regression were used to identify the factors that are significantly associated with conversion.
Results:
We identified 9,008 patients: 84.0% were female, 77.8% were Hispanic, and 75.2% were uninsured, with a median age of 37 (29-47) years. 10.5% of patients were ASA 3 or 4 with comorbidities including hypertension in 19.8% of cases, diabetes mellitus in 10.2% of cases, and renal failure in 0.5% of cases. The majority (81.8%) of cases were performed between 7 a.m. and 3 p.m. Ambulatory cases accounted for 31.1% of patients. There were 451 converted cholecystectomies across all case types – a conversion rate of 5.0%. On multivariable analysis, predictors of conversion were male gender (odds ratio (OR)=2.68; 95% confidence interval (CI): 2.09-3.43), increased age (OR=1.02; 95% CI: 1.02-1.03), diabetes mellitus (OR=1.42; 95% CI: 1.04-1.95), increased BMI (OR=1.018; 95% CI: 1.001-1.03), increased WBC count (OR=1.034; 95% CI: 1.01-1.06), and increased alkaline phosphatase (OR=1.002; 95% CI: 1.001-1.003). Ambulatory cases were associated with a decreased conversion rate (3.1%) compared to inpatient cases (OR=0.458, 95% CI: 0.4-0.9). Patients seen in 2007-2010 had a higher conversion rate than those in 2011-2015 (6% vs. 4.3%, OR=1.49, 95% CI: 1.18-1.88). There was no difference in conversion rate by surgery start time, with a rate of 5.2% for 7370 cases from 7 a.m. to 3 p.m. and a rate of 5.7% for 1638 cases from 3:01 p.m. to 6:59 a.m. (p=0.45).
Conclusion:
Male gender, age, BMI, high ASA status, diabetes mellitus, WBC, alkaline phosphatase, and non-ambulatory case status were independent predictors of conversion. Conversion rate did not vary by time of surgery. Application of these pre-operative patient factors as a predictive model for increased risk of conversion can facilitate improved planning and management.