Interrelationship of preoperative anemia, intraoperative anemia, and red blood cell transfusion as potentially modifiable risk factors for acute kidney injury in cardiac surgery: a historical multicentre cohort study.

PURPOSE: Acute kidney injury (AKI) is a potentially serious complication of cardiac surgery. Anemia and red blood cell (RBC) transfusion have individually been identified as potentially modifiable risk factors, but their interrelationship with AKI has not been clearly defined. The purpose of this study was to explore the interrelationship of preoperative anemia, intraoperative anemia, and RBC transfusion on the day of surgery with AKI in cardiac surgery. METHODS: This historical cohort study included 16 hospitals, each contributing data on approximately 100 consecutive patients who underwent cardiac surgery with cardiopulmonary bypass. Acute kidney injury was defined as a > 50% increase in creatinine levels during the first postoperative week. Multivariable regression was used to identify the interrelationship between preoperative anemia (hemoglobin < 130 g·L(-1) in males and < 120 g·L(-1) in females), intraoperative anemia (hemoglobin < 80 g·L(-1) during cardiopulmonary bypass), RBC transfusion on the day of surgery, and their interaction terms, after adjusting for site and baseline AKI risk. RESULTS: Of the 1,444 patients included in the study, 541 (37%) had preoperative anemia, 501 (35%) developed intraoperative anemia, 619 (43%) received RBC transfusions, and 238 (16%) developed AKI. After risk-adjustment, an individual with the combination of these three risk factors had a 2.6-fold (95% confidence interval 2.0 to 3.3) increase in the relative risk of AKI over an individual with none of these risk factors. CONCLUSIONS: Preoperative anemia, intraoperative anemia, and RBC transfusion on the day of surgery are interrelated risk factors for AKI after cardiac surgery. Targeting these risk factors may reduce the burden of AKI.

Does removing Mannitol and Voluven from the priming fluid of the cardiopulmonary bypass circuit have clinical effects?

The Auckland Hospital cardiothoracic unit recently removed Mannitol and Voluven from its Plasma-lyte-based cardiopulmonary bypass (CPB) priming fluid. Like with any change to practice, a comprehensive audit should be performed to identify positive or negative effects. The aim of this retrospective analysis was to investigate the effect of changing the CPB prime constituents on fluid balance and clinical outcome parameters. Clinical records were reviewed for 100 consecutive patients undergoing primary, isolated coronary artery bypass grafting (CABG), 50 patients before the prime change and 50 after. All data were collated into a central database for analysis. Mean arterial pressure while on bypass was higher in the new prime group (61.5 mmHg versus 57.5 mmHg, p = .002). There was no significant difference in hematocrit, hemoglobin, serum sodium, serum potassium, or creatinine postoperatively between groups. In regard to important outcomes such as postoperative weight and fluid balance, time on ventilation, length of stay in the intensive care unit (ICU) or hospital, and mortality, there were no significant differences. Interestingly, new prime group spent a smaller proportion of their time in the ICU on mechanical ventilation (23% versus 36%, p = .022). Mannitol and Voluven, like with all drugs, carry their own potential adverse effects. This study demonstrates that removing Mannitol and Voluven from priming fluid did not have any detrimental effect on electrolytes, fluid status, and other important outcomes in this consecutive series of patients having primary isolated CABG surgery. The risk-benefit balance combined with the obvious economic benefit clearly favors removing Mannitol and Voluven from priming fluids.

A randomized comparison between records made with an anesthesia information management system and by hand, and evaluation of the Hawthorne effect.

PURPOSE: Anesthesia information management system (AIMS) technology is designed to facilitate high-quality anesthetic recordkeeping. We examined the hypothesis that no difference exists between AIMS and handwritten anesthetic records in regard to the completeness of important information contained as text data. We also investigated the effect of observational research on the completeness of anesthesiologists' recordkeeping. METHODS: As part of a larger randomized controlled trial, participants were randomized to produce 400 anesthetic records, either handwritten (n = 200) or using an AIMS (n = 200). Records were assessed against a 32-item checklist modified from a clinical guideline. Intravenous agent and bolus recordings were quantified, and data were compared between handwritten and AIMS records. Records produced with intensive research observation during the initial phase of the study (n = 200) were compared with records produced with reduced intensity observation during the final phase of the study (n = 200). RESULTS: The AIMS records were more complete than the handwritten records (mean difference 7.1%; 95% confidence interval [CI] 5.6 to 8.6%; P < 0.0001), with higher completion rates for six individual items on the checklist (P < 0.0001). Drug annotation data were equal between arms. The records completed early in the study, during a period of more intense observation, were more thorough than subsequent records (87.3% vs 81.6%, respectively; mean difference 5.7%; 95% CI 4.2 to 7.3%; P < 0.0001). CONCLUSIONS: The AIMS records were more complete than the handwritten records for 32 predefined items. The potential of observational research to influence professional behaviour in an anesthetic context was confirmed. This trial was registered at the Australian New Zealand Clinical Trials Registry No 12608000068369.

Timely bolus insulin for glucose control during cardiopulmonary bypass.

Hyperglycemia during cardiopulmonary bypass (CPB) with glucose containing cardioplegia is common; normoglycemia is difficult to maintain and failure to do so may result in worse outcomes. The purpose of this quality improvement initiative was to show that a simple timely insulin bolus is more effective for glucose control during CPB with glucose containing cardioplegia than conventional (not standardized) glucose management in historical case-matched controls. A single bolus of insulin (.2 international units per kilogram; iu/kg) was administered, at the time of aortic cannulation, to 211 consecutive patients undergoing cardiac surgery with CPB and glucose containing cardioplegia. A further .1 iu/kg bolus of insulin was given for blood glucose (BG) measurements greater than 10.0 mmol/L (180 mg/dL) during CPB. The control group of 211 historical case-matched patients had glucose management according to anesthesiologist preference (insulin as a bolus, bolus plus infusion, infusion only, or no insulin). The frequency of hyperglycemia (BG > 11.0 mmol/L; 198 mg/dL) during CPB was significantly less in the study group (22; 10.5%) than in the control group (117; 55.5%) (p < .0001). Hyperglycemia in the first 6 hours in the intensive care unit was also significantly less frequent in the study group (5; 2.4%) than in the control group (14; 6.6%) (p = .03). Severe hypoglycemia (BG < 2.8 mmol/L; 50.4 mg/dL) occurred in one patient (.47%) in the timely bolus insulin group and five patients (2.3%) in the control group (p = .09). The timely bolus insulin method is more efficacious, but equally safe, in preventing hyperglycemia during CPB with glucose containing cardioplegia, compared with conventional (not standardized) insulin treatment in historical case-matched controls.