Patrick Lecomte

Poor Intraoperative Blood Glucose Control Is Associated with a Worsened Hospital Outcome after Cardiac Surgery in Diabetic Patients

Background: Tight perioperative control of blood glucose improves the outcome of diabetic patients undergoing cardiac surgery. Because stress response and cardiopulmonary bypass can induce profound hyperglycemia, intraoperative glycemic control may become difficult. The authors undertook a prospective cohort study to determine whether poor intraoperative glycemic control is associated with increased intrahospital morbidity. Methods: Two hundred consecutive diabetic patients undergoing on-pump heart surgery were enrolled. A standard insulin protocol based on subcutaneous intermediary insulin was given the morning of the surgery. Intravenous insulin therapy was initiated intraoperatively from blood glucose concentrations of 180 mg/dl or greater and titrated according to a predefined protocol. Poor intraoperative glycemic control was defined as four consecutive blood glucose concentrations greater than 200 mg/dl without any decrease in despite insulin therapy. Postoperative blood glucose concentrations were maintained below 140 mg/dl by using aggressive insulin therapy. The main endpoints were severe cardiovascular, respiratory, infectious, neurologic, and renal in-hospital morbidity. Results: Insulin therapy was required intraoperatively in 36% of patients, and poor intraoperative glycemic control was observed in 18% of patients. Poor intraoperative glycemic control was significantly more frequent in patients with severe postoperative morbidity (37% vs. 10%; P < 0.001). The adjusted odds ratio for severe postoperative morbidity among patients with a poor intraoperative glycemic control as compared with patients without was 7.2 (95% confidence interval, 2.7–19.0). Conclusion: Poor intraoperative control of blood glucose concentrations in diabetic patients undergoing cardiac surgery is associated with a worsened hospital outcome after surgery.

Dynamic Tight Glycemic Control During and After Cardiac Surgery Is Effective, Feasible, and Safe

BACKGROUND: Tight blood glucose control reduces mortality and morbidity in critically ill patients, but intraoperative glucose control during cardiac surgery is often difficult, and risks hypoglycemia. In this study, we evaluated the safety and efficacy of a nurse-driven insulin protocol (the Aalst Glycemia Insulin Protocol) for achieving a target glucose level of 80–110 mg/dL during cardiac surgery and in the intensive care unit (ICU). METHODS: We included 483 nondiabetics and 168 diabetics scheduled for cardiac surgery with cardiopulmonary bypass. To anticipate rapid perioperative changes in insulin requirement and/or sensitivity during surgery, we developed a dynamic algorithm presented in tabular form, with rows representing blood glucose ranges and columns representing insulin dosages based on the patients’ insulin sensitivity. The algorithm adjusts insulin dosage based on blood glucose level and the projected insulin sensitivity (e.g., reduced sensitivity during cardiopulmonary bypass and normalizing sensitivity after surgery). RESULTS: A total of 18,893 blood glucose measurements were made during and after surgery. During surgery, the mean glucose level in nondiabetic patients was within targeted levels except during (112 ± 17 mg/dL) and after rewarming (113 ± 19 mg/dL) on cardiopulmonary bypass. In diabetics, blood glucose was decreased from 121 ± 40 mg/dL at anesthesia induction to 112 ± 26 mg/dL at the end of surgery (P < 0.05), with 52.9% of patients achieving the target. In the ICU, the mean glucose level was within targeted range at all time points, except for diabetics upon ICU arrival (113 ± 24 mg/dL). Of all blood glucose measurements (operating room and ICU), 68.0% were within the target, with 0.12% of measurements in nondiabetics and 0.18% in diabetics below 60 mg/dL. Hypoglycemia < 50 mg/dL was avoided in all but four (0.6%) patients (40 mg/dL was the lowest observed value). CONCLUSIONS: The Aalst Glycemia Insulin Protocol is effective for maintaining tight perioperative blood glucose control during cardiac surgery with minimal risk of hypoglycemia.

Comparative Cardiac Effects of Terlipressin, Vasopressin, and Norepinephrine on an Isolated Perfused Rabbit Heart

Background: Terlipressin, a synthetic analog of arginine-vasopressin (AVP), has been proposed as an effective vasopressive therapy in catecholamine-resistant vasodilatory shock. Although beneficial effects of terlipressin on systemic arterial pressure have been clearly demonstrated, its intrinsic effects on coronary circulation and myocardial performances remain unknown. Methods: The authors compared the coronary and myocardial effects of terlipressin (1–100 nm, n = 10), AVP (10–1000 pm, n = 10), and norepinephrine (1–100 nm, n = 10) on an erythrocyte-perfused isolated rabbit heart. The cardiac effects of terlipressin were also assessed in erythrocyte-perfused hearts in which the myocardial oxygen delivery was maintained constant and buffer-perfused hearts. Finally, the cardiac effects of terlipressin and AVP were studied in hearts pretreated by [d(CH2)5Tyr(Me)]AVP (0.1 &mgr;m), a selective V1a receptor antagonist. Results: Norepinephrine induced a biphasic coronary effect associated with a concentration-dependent increase in myocardial performances. AVP and terlipressin significantly decreased coronary blood flow and impaired myocardial performances from 30 pm and 30 nm, respectively (P < 0.05). The cardiac side-effects of terlipressin were confirmed in buffer-perfused hearts but the maintenance of a constant myocardial oxygen delivery constant abolished its effects on myocardial performances. The cardiac effects induced by terlipressin and AVP were nearly completely abolished on hearts pretreated by [d(CH2)5Tyr(Me)]AVP. Conclusions: On isolated rabbit heart, terlipressin induced a coronary vasopressor effect and in turn myocardial depression only at supratherapeutic concentrations (≥30 nm). Its effects are mainly mediated via V1a receptors. However, these potential negative side effects on the heart were less pronounced than were those of AVP.

Remifentanil induces systemic arterial vasodilation in humans with a total artificial heart

BackgroundTo assess intrinsic vascular effects of remifentanil, increased concentrations were infused in critically ill patients with a total artificial heart. MethodsIn the early postoperative period after implantation of a total artificial heart, nine ventilated patients requiring short general anesthesia were included in this study. After anesthesia was induced with 0.3 mg/kg intravenous etomidate, the artificial heart settings were modified to render cardiac output “preload-independent.” While maintenance of anesthesia was ensured by a continuous infusion of etomidate, increased concentrations of remifentanil (from 0.1 to 1 &mgr;g · kg−1 · min−1) were infused in steps of 5 min under hemodynamic monitoring, including left and right atrial pressures, systemic and pulmonary arterial pressures, and left and right cardiac indices. The invasive procedure was started under the highest concentration of remifentanil tolerated by the patient. Infusion of remifentanil was stopped at the end of the invasive procedure, while etomidate infusion was maintained. New hemodynamic measurements were performed at the end of the 12-min recovery period. ResultsRemifentanil produced a dose-dependent and significant decrease in systemic arterial pressure and vascular resistances (n = 9) from a concentration of 0.25 &mgr;g · kg−1 · min−1. No significant changes were observed on pulmonary vascular resistances (n = 6). Neither right (n = 9) nor left (n = 6) atrial pressures were affected by remifentanil infusion. Hemodynamic variables returned to baseline value over the 12-min recovery period. ConclusionsIn humans with a total artificial heart, remifentanil induces a systemic arterial vasodilation without significant effect on the capacitance vessels.

Predictive performance and variability of the cardiac anesthesia risk evaluation score.

Background: The Cardiac Anesthesia Risk Evaluation (CARE) score, a simple Canadian classification for predicting outcome after cardiac surgery, was evaluated in 556 consecutive patients in Paris, France. The authors compared its performance to those of two multifactorial risk indexes (European System for Cardiac Operative Risk Evaluation [EuroSCORE] and Tu score) and tested its variability between groups of physicians (anesthesiologists, surgeons, and cardiologists). Methods: Each patient was simultaneously assessed using the three scores by an attending anesthesiologist in the immediate preoperative period. In a blinded study, the CARE score category was also determined by a cardiologist the day before surgery, by a surgeon in the operating room, and by a second anesthesiologist at arrival in intensive care unit. Calibration and discrimination for predicting outcomes were assessed by goodness-of-fit test and area under the receiver operating characteristic curve, respectively. The level of agreement of the CARE scoring between the three physicians was then assessed. Results: The calibration analysis revealed no significant difference between expected and observed outcomes for the three classifications. The areas under the receiver operating characteristic curves for mortality were 0.77 with the CARE score, 0.78 with the EuroSCORE, and 0.73 with the Tu score (not significant). The agreement rate of the CARE scoring between two anesthesiologists, between anesthesiologists and surgeons, and between anesthesiologists and cardiologists were 90%, 83%, and 77%, respectively. Conclusions: Despite its simplicity, the CARE score predicts mortality and major morbidity as well the EuroSCORE. In addition, it remains devoid of significant variability when used by groups of physicians of different specialties.

Management of tight intraoperative glycemic control during off-pump coronary artery bypass surgery in diabetic and nondiabetic patients.

OBJECTIVES To optimize intra- and postoperative insulin management in cardiac surgical patients. DESIGN A prospective, randomized, open-label, single-center study. SETTING A large nonuniversity hospital. PARTICIPANTS Sixty diabetics and 60 nondiabetics undergoing off-pump cardiac bypass surgery. INTERVENTIONS Intra- and postoperative tight glycemic control were achieved using different approaches with a modified insulin protocol. MEASUREMENTS AND MAIN RESULTS Nondiabetics were divided randomly: in the ND-ind group (n = 30), insulin was started at induction according to preinduction blood glucose (BG) concentrations. In group ND >110 (n = 30), insulin was started when BG concentrations exceeded 110 mg/dL during surgery. Up to 85% of the ND >110 group started on insulin intraoperatively. Intraoperatively, the ND-ind group had more BG within target (80-110 mg/dL) (p = 0.002), less BG >130 mg/dL (p = 0.015), and more BG between 70 and 79 mg/dL (p = 0.002). In diabetics, BG concentration was checked every 30 (DM-30), n = 30) versus 60 minutes (DM-60, n = 30) to improve the protocols performance. Intraoperatively, there were more BG concentrations within target (80-110 mg/dL) (p = 0.02) and less >130 mg/dL (p = 0.0002) in the DM-30 group. During surgery, the hyperglycemic index and the glycemic penalty index were lower in the ND-ind group (p < 0.05). Postoperatively, the mean BG concentrations, hyperglycemic index, and glycemic penalty index in diabetics and nondiabetics were comparable between groups (p < 0.05). In the overall 2,641 BG samples, the lowest BG concentration in the operating room was 71 and in the intensive care unit (ICU) it was 61 mg/dL. CONCLUSIONS In diabetics and nondiabetics undergoing off-pump coronary artery bypass surgery, tight perioperative glycemic control is feasible and efficient, with minimal risks for hypo- and hyperglycemia. In nondiabetics, starting insulin therapy from induction onwards results in more measurements within target, without affecting the mean BG. In diabetics, decreasing the sampling interval from 60 to 30 minutes results in more measurements within target and in a mean blood glucose within target at ICU arrival.

Perioperative blood glucose management in patients undergoing tumor hepatectomy

STUDY OBJECTIVE To determine whether our institutional insulin management (modified Atlanta) protocol is efficient and safe in controlling blood glucose levels in the perioperative period in surgical patients undergoing tumor hepatectomy. DESIGN Retrospective study. SETTING Large community hospital. PATIENTS 20 consecutive patients undergoing liver resection for hepatocellular carcinoma, liver metastasis, or other hepatobiliary tumors. INTERVENTIONS AND MEASUREMENTS All patients continuously received intravenous glucose (5% dextrose in water, one mL/kg/hr); insulin was administered according to a strict algorithm, and dose adjustments were based on measurements of whole-blood glucose intraoperatively at one-hour intervals, and in the intensive care unit (ICU). Lower and upper blood glucose limits were set at 85 mg/dL and 110 mg/dL, respectively, in the operating room (OR). In the ICU, lower and upper limits were 90 mg/dL and 140 mg/dL, respectively. MAIN RESULTS Intraoperatively, 51.3% of measurements were within the target range. In the ICU, 75.2% of measurements showed a blood glucose level of 90 - 140 mg/dL. Two of 78 (2.6%) and two of 363 (0.5%) measurements had a blood glucose level < 70 mg/dL in the OR and ICU, respectively. The lowest blood glucose levels were 65 mg/dL (OR) and 66 mg/dL (ICU). CONCLUSIONS The modified Atlanta protocol is efficient and safe in controlling blood glucose levels in the perioperative period of hepatic tumor resection. Because of decreased insulin needs in the ICU, the use of a more liberal algorithm successfully reduced the risk of hypoglycemia.

The Coronary and Myocardial Effects of Remifentanil and Sufentanil in the Erythrocyte-perfused Isolated Rabbit Heart

Remifentanil-induced hypotension may be associated with adverse ischemic myocardial events. Although these events can be easily attributed to a decrease in coronary pressure perfusion, we tested the hypothesis that remifentanil could directly affect coronary vasomotor tone. Therefore, we assessed intrinsic coronary and myocardial in vitro effects of remifentanil on a Langendorff’s rabbit model and compared these effects with those provoked by similar intracoronary concentrations of sufentanil. Under general anesthesia, hearts from New Zealand rabbits were rapidly excised and mounted on an erythrocyte-perfused and isolated heart preparation. The hearts were then exposed to increasing concentrations (10-1000 nM) of either remifentanil (n = 10) or sufentanil (n = 8). Between each concentration, hearts were allowed to return to baseline status. The maximal coronary and myocardial effects of each concentration of both drugs were noted. Baseline values of coronary blood flow and myocardial performances were comparable between groups. Neither remifentanil nor sufentanil induced significant coronary and myocardial effects. These results suggest that myocardial ischemia, which may occur during remifentanil-induced hemodynamic disturbances, especially in cardiac patients, is only related to a decrease in coronary perfusion pressure provoked by peripheral hemodynamic changes.