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

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.

Time frame: six weeks postoperatively

Population: Inclusion \> age 21, underwent elective or urgent Coronary Artery Bypass Graft (CABG) with or without combined valve surgery or valve surgery alone, on or off cardiopulmonary bypass (CPB). Exclusions were patients diagnosed with immunosuppression, end stage organ disease, or active infections.

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.

Time frame: Post cardiopulmonary bypass and postoperative day 1 through 5

Population: Inclusion \> age 21, underwent elective or urgent CABG with or without combined valve surgery or valve surgery alone, on or off CPB. Exclusions were patients diagnosed with immunosuppression, end stage organ disease, or active infections. Six participants had \> 50% missing data and were dropped from this analysis (4 tight, 1 in other two groups).

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.

Time frame: Post CPB and Postoperative days 1 through 5

Population: Inclusion \> age 21, underwent elective or urgent CABG with or without combined valve surgery or valve surgery alone, on or off CPB. Exclusions were patients diagnosed with immunosuppression, end stage organ disease, or active infections. Six participants had \> 50% missing data and were dropped from this analysis (4 tight, 1 in other two groups).

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.

Time frame: 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

Population: Inclusion \> age 21, underwent elective or urgent CABG with or without combined valve surgery or valve surgery alone, on or off CPB. Exclusions were patients diagnosed with immunosuppression, end stage organ disease, or active infections.

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.

Time frame: 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

Population: Inclusion \> age 21, underwent elective or urgent CABG with or without combined valve surgery or valve surgery alone, on or off CPB. Exclusions were patients diagnosed with immunosuppression, end stage organ disease, or active infections. No data analysis could be performed because there were too few episodes of glycemic instability.

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.

Time frame: 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

Population: Inclusion \> age 21, underwent elective or urgent CABG with or without combined valve surgery or valve surgery alone, on or off CPB. Exclusions were patients diagnosed with immunosuppression, end stage organ disease, or active infections.