The Effect of Tight Glycemic Control on Surgical Site Infection Rates in Patients Undergoing Open Heart Surgery

Not Applicable

Completed

Conditions: Diabetes
Hyperglycemia
Surgical Site Infection

Interventions: Drug: Tight Glycemic
Drug: Conventional Glycemic
Drug: Standard Glycemic

Registration Number: NCT01831154

Lead Sponsor: James A. Haley Veterans Administration Hospital

Brief Summary: The purpose of this study was to investigate the effects of three different glycemic treatment conditions (tight, conventional, and standard) in the intraoperative period on: 1) postoperative surgical site infections, and 2) postoperative procalcitonin, and C-reactive protein levels in patients undergoing open-heart surgery. Secondary aims of the study were to investigate the effects of the three glycemic treatment conditions on: 1) intraoperative blood glucose; 2) intraoperative glycemic stability; and 3) intensive care unit length of stay, in patients undergoing open-heart surgery.

Detailed Description: An experimental design with a multilevel, single factor, within-subjects design was utilized. Patients were nested within anesthesia provider teams. The design was counterbalanced by means of a Latin square, where each of three anesthesia provider teams dispensed each of three glycemic treatment conditions once.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 37

Inclusion Criteria

over the age of 21
on cardiopulmonary bypass or off cardiopulmonary
elective or urgent coronary artery bypass graft (CABG) surgery
CABG with or without combined valve surgery
valve surgery

Exclusion Criteria

chronically immunosuppressed
suffered from end-stage organ disease
currently had active infections
underwent emergent or salvage CABG surgery
had an implanted insulin pump
were in another interventional clinical trial.

Study & Design

Study Type: INTERVENTIONAL

Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Tight Glycemic Group	Tight Glycemic	The tight glycemic group received a continuous intravenous infusion of regular insulin in the intraoperative period titrated per a modified Portland Protocol from Vanderbilt University Medical Center, Tennessee. The initial bolus of insulin and insulin infusion was initiated prior to induction of anesthesia if the morning blood glucose was greater than 149 mg/dl or any time intraoperatively the blood glucose elevated above 149 mg/dl.The titration of insulin for the tight glycemic group maintained blood glucose levels between 110-149 mg/dl throughout the intraoperative period. The intraoperative blood glucose was titrated to blood glucose levels sampled every 30 minutes.Upon transfer to the intensive care unit the protocol ended and all subjects received the same glycemic control.
Conventional Glycemic Group	Conventional Glycemic	The conventional glycemic group received a continuous intravenous infusion of regular insulin in the intraoperative period titrated per a modified Portland Protocol from Vanderbilt University Medical Center, Tennessee. The initial insulin bolus and infusion was initiated prior to induction of anesthesia if the morning blood glucose was greater than 180 mg/dl or any time intraoperatively that the blood glucose elevated above 180 mg/dl. The insulin infusion was titrated throughout the intraoperative period to maintain blood glucose levels between 150-180 mg/dl.The intraoperative blood glucose was titrated to blood glucose levels sampled every 30 minutes. Upon transfer to the ICU the intraoperative protocol ended and all subjects received the standardized glycemic control for the ICU.
Standard Glycemic Group	Standard Glycemic	The standard glycemic group received intravenous injections of regular insulin in the intraoperative period titrated per the usual care protocol utilized at the study site. The initial bolus of insulin was initiated prior to induction of anesthesia if the morning blood glucose is greater than 180 mg/dl or any time intraoperatively that the blood glucose rises above 180 mg/dl. The intraoperative blood glucose was titrated to blood glucose levels sampled every 30 minutes.Upon transfer to the ICU the intraoperative protocol ended and all subjects received the standardized glycemic control for the ICU.

Primary Outcome Measures

Name	Time	Method
Number of Participants Undergoing Open Heart Surgery With Postoperative Surgical Site Infection	six weeks postoperatively	The presence or absence of deep, or/and superficial sternal wound infection and deep, superficial harvest site infection within in six weeks postoperatively was a primary outcome variable. Infection assessment was performed during the intensive care phase, at hospital discharge, two-week post hospital discharge and six-week post hospital discharge by independent blinded researchers that were part of the cardiothoracic team.
The Effect of Intraoperative Tight Glycemic Control on Postoperative Procalcitonin Plasma Levels in Patients Undergoing Open Heart Surgery	Post CPB and Postoperative days 1 through 5	Procalcitonin concentrations were collected in addition to clinical signs for indications of infection. These biomarker concentrations were collected after successful separation from cardiopulmonary bypass (CPB), and every morning for five days postoperatively. Values were drawn by anesthesia providers and intensive care unit (ICU) registered nurses or laboratory personnel with the standard morning blood work. All procalcitonin blood values from post cardiopulmonary bypass through postoperative day 5 were collected. The outcome measure was mean procalcitonin values with standard deviation.
The Effect of Intraoperative Tight Glycemic Control on Postoperative C-Reactive Protein Plasma Levels in Patients Undergoing Open Heart Surgery	Post cardiopulmonary bypass and postoperative day 1 through 5	C-Reactive Protein concentrations were collected in addition to clinical signs for indications of infection. These biomarker concentrations were collected after successful separation from cardiopulmonary bypass (CPB), and every morning for five days postoperatively. Values were drawn by anesthesia providers and intensive care unit (ICU) registered nurses or laboratory personnel with the standard morning blood work. All C-Reactive Protein blood values from post cardiopulmonary bypass through postoperative day 5 were collected. The outcome measure was mean C-Reactive Protein values with standard deviation.

Secondary Outcome Measures

Name	Time	Method
The Effect of Tight Glycemic Control on Intensive Care Unit Length of Stay in Patients Undergoing Open Heart Surgery	ICU days measured every day the patient stayed in ICU starting with entry into the ICU from the Operating Room until discharge from the ICU to the ward	Length of stay (LOS) in the intensive care unit was measured by the total number of days each patient stayed in the intensive care unit.
Intraoperative Blood Glucose Levels in Patients Undergoing Open Heart Surgery	Blood glucose measured every 30 minutes starting on entry into the operating room until exiting the operating room or 240 minutes, whichever event occurred first	Blood glucose values were obtained every 30 minutes in the intraoperative period, and were drawn and recorded by the certified registered nurse anesthetist (CRNA) performing the anesthetic. Repeated measured ANOVA with Greenhouse-Geisser correction was employed to determine if participants assigned to the tight glycemic group yielded lower blood glucose levels intraoperatively (every 30 minutes for 240 minutes) than the other two interventions. All blood glucose measures over the intraoperative period were averaged to produce a mean and standard deviation comparing the tight glycemic group to the other two interventional groups, Data points were blood glucose testing collected every 30 minutes starting on entry into the operating room.
Intraoperative Glycemic Stability in Patients Undergoing Open Heart Surgery Compared Between Three Glycemic Protocols.	Measures of blood glucose every 30 minutes starting on entry into the operating room until exiting the operating room or 240 minutes whichever event occurred first	Intraoperative glycemic stability was operationalize as how often blood glucose levels were maintained as normal or maintained in the preset target ranges for each group. If intraoperative blood glucose levels fell outside of normal (hypoglycemia or hyperglycemia) or, outside the preset target ranges, for each protocol, for 3 consecutive blood glucoses (1.5 hours) despite insulin therapy a marker of inadequate glycemic control was recorded.