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Background: Lactic acidosis is a rare but serious complication associated with metformin therapy in certain high-risk patients. NICE guidelines and the British National Formulary advise the discontinuation of metformin before surgery. The drug manufacturer's datasheet advises the withdrawal of metformin 48 h before surgery. However, the data regarding perioperative use of metformin is scarce. Aims: To evaluate the effect of continuation of metformin till night before surgery on lactate levels in patients undergoing coronary artery bypass graft (CABG) surgery. Materials and Methods: In this prospective cohort study, 1,800 consecutive patients who underwent CABG between 1st November 2015 and 31st October 2016 were enrolled. Following exclusion criteria, a total of 790 subjects were included for final analysis. Three-hundred and eight seven (48.9%) patients with diabetes received metformin till night before surgery (Met group), 239 (30.3%) patients with diabetes were non-metformin users (Non-Met group), and 164 (20.8%) patients were having no diabetes (Non-Diab group). Lactate levels and arterial pH were measured using arterial blood gas machine. Postoperative morbidity outcome data were obtained by collecting clinical data, routine biochemistry, and chest imaging. Results: The mean metformin dose was 1,124.6 mg/day (SD: 509.3; range: 500–2,500 mg/day). Mean postoperative lactate levels were 1.91 ± 0.7 in Met group, 2.04 ± 0.79 in Non-Met group, and 2.07 ± 0.78 in Non-Diab group. Lactic acidosis occurred in 41 patients and there was no difference among the groups [Met group = 18 (4.7%); Non-Met group = 14 (5.9%)]. Among secondary outcome measures, acute renal failure occurred more frequently in diabetic patients [Met group = 46 (11.9%) and Non-Met group = 32 (13.4%)] as compared with non-diabetic patients. There were no differences with regard to pneumonia, length of ICU stay, and duration of ventilatory support among the three groups. Conclusions: Continuation of metformin till night before surgery is not associated with significant changes in lactate levels in patients undergoing CABG. [ABSTRACT FROM AUTHOR]

Aim: Inpatient hyperglycemia management is essential, but difficult to achieve especially in a large volume cardiac surgery setup, thus necessitating use of nurse-led insulin protocols. A rapid flux of nurses dealing with a huge workload has been a cause for traditionally not using nurse-led protocols in most Indian institutes. The challenges we faced were to have a simple protocol for the nurses to accept it without compromising on glycemic control. Therefore, this observational study was planned to measure the efficacy and safety of the insulin infusion protocol in cardiac surgery patients. Materials and Methods: Insulin protocol was implemented, using seven fixed columns of infusion with the nurse making decisions to initiate and titrate doses based on simple rules. Blood glucose (BG) data captured from blood gas analyzers (glucometrics) in the intervention group (i.e., after protocol implementation) were compared to control group (i.e., before the protocol implementation). Results: The mean BG for the first 48 h was lower in the intervention group as compared to control group, without an increase in the episodes of hypoglycemia. The nurses found the protocol easy to understand, less time-consuming and there was no protocol deviation over 8 months after implementation. Conclusion: A small change in the process, allowing nurses to titrate insulin doses based on some rules and having seven fixed columns of insulin infusion rates, improved glycemic control and efficiency. [ABSTRACT FROM AUTHOR]

Hyperglycemia is common in patients undergoing cardiac surgery and is associated with poor outcomes. This is a review of the perioperative insulin protocol being used at Medanta, the Medicity, which has a large volume cardiac surgery setup. Preoperatively, patients are usually continued on their preoperative outpatient medications. Intravenous insulin infusion isintiated postoperatively and titrated using a column method with a choice of 7 scales. Insulin dose is calculated as a factor of blood glucose and patient's estimated insulin sensitivity. A comparison of this protocol is presented with other commonly used protocols. Since arterial blood gas analysis is done every 4 hours for first two days after cardiac surgery, automatic data collection from blood gas analyzer to a central database enables collection of glucose data and generating glucometrics. Data auditing has helped in improving performance through protocol modification. [ABSTRACT FROM AUTHOR]