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

Study Overview
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Brief Summary
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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
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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.

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

Conditions
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Diabetes, Hyperglycemia, Surgical Site Infection

Intervention / Treatment
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* Drug: Tight Glycemic
* Drug: Conventional Glycemic
* Drug: Standard Glycemic


Participation Criteria
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Eligibility Criteria
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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.

Ages Eligible for Study
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Minimum Age: 21 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Tight Glycemic Group<br>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. | Drug: Tight Glycemic<br>* The insulin infusion consisted of 100 units of regular insulin in 100 ml of normal saline.<br>|
| Experimental: Conventional Glycemic Group<br>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. | Drug: Conventional Glycemic<br>* The insulin infusion consisted of 100 units of regular insulin in 100 ml of normal saline.<br>|
| Experimental: Standard Glycemic Group<br>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. | Drug: Standard Glycemic<br>* Insulin was Regular Insulin administered intravenous bolus.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of Participants Undergoing Open Heart Surgery With Postoperative Surgical Site Infection | 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. | six weeks postoperatively | 
| The Effect of Intraoperative Tight Glycemic Control on Postoperative Procalcitonin Plasma Levels in Patients Undergoing Open Heart Surgery | 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. | Post CPB and Postoperative days 1 through 5 | 
| The Effect of Intraoperative Tight Glycemic Control on Postoperative C-Reactive Protein Plasma Levels in Patients Undergoing Open Heart Surgery | 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. | Post cardiopulmonary bypass and postoperative day 1 through 5 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Intraoperative Blood Glucose Levels in Patients Undergoing Open Heart Surgery | 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. | 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 | 
| The Effect of Tight Glycemic Control on Intensive Care Unit Length of Stay in Patients Undergoing Open Heart Surgery | 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. | 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 | 
| Intraoperative Glycemic Stability in Patients Undergoing Open Heart Surgery Compared Between Three Glycemic Protocols. | 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. | 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 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Glycemic control