Michal Lips

Comparison of Three Protocols for Tight Glycemic Control in Cardiac Surgery Patients

OBJECTIVE We performed a randomized trial to compare three insulin-titration protocols for tight glycemic control (TGC) in a surgical intensive care unit: an absolute glucose (Matias) protocol, a relative glucose change (Bath) protocol, and an enhanced model predictive control (eMPC) algorithm. RESEARCH DESIGN AND METHODS A total of 120 consecutive patients after cardiac surgery were randomly assigned to the three protocols with a target glycemia range from 4.4 to 6.1 mmol/l. Intravenous insulin was administered continuously or in combination with insulin boluses (Matias protocol). Blood glucose was measured in 1- to 4-h intervals as requested by the protocols. RESULTS The eMPC algorithm gave the best performance as assessed by time to target (8.8 ± 2.2 vs. 10.9 ± 1.0 vs. 12.3 ± 1.9 h; eMPC vs. Matias vs. Bath, respectively; P < 0.05), average blood glucose after reaching the target (5.2 ± 0.1 vs. 6.2 ± 0.1 vs. 5.8 ± 0.1 mmol/l; P < 0.01), time in target (62.8 ± 4.4 vs. 48.4 ± 3.28 vs. 55.5 ± 3.2%; P < 0.05), time in hyperglycemia >8.3 mmol/l (1.3 ± 1.2 vs. 12.8 ± 2.2 vs. 6.5 ± 2.0%; P < 0.05), and sampling interval (2.3 ± 0.1 vs. 2.1 ± 0.1 vs. 1.8 ± 0.1 h; P < 0.05). However, time in hypoglycemia risk range (2.9–4.3 mmol/l) in the eMPC group was the longest (22.2 ± 1.9 vs. 10.9 ± 1.5 vs. 13.1 ± 1.6; P < 0.05). No severe hypoglycemic episode (<2.3 mmol/l) occurred in the eMPC group compared with one in the Matias group and two in the Bath group. CONCLUSIONS The eMPC algorithm provided the best TGC without increasing the risk of severe hypoglycemia while requiring the fewest glucose measurements. Overall, all protocols were safe and effective in the maintenance of TGC in cardiac surgery patients.

Perioperative Tight Glucose Control Reduces Postoperative Adverse Events in Nondiabetic Cardiac Surgery Patients

CONTEXT Tight glucose control (TGC) reduces morbidity and mortality in patients undergoing elective cardiac surgery, but only limited data about its optimal timing are available to date. OBJECTIVE The purpose of this article was to compare the effects of perioperative vs postoperative initiation of TGC on postoperative adverse events in cardiac surgery patients. DESIGN This was a single center, single-blind, parallel-group, randomized controlled trial. SETTINGS The setting was an academic tertiary hospital. PARTICIPANTS Participants were 2383 hemodynamically stable patients undergoing major cardiac surgery with expected postoperative intensive care unit treatment for at least 2 consecutive days. INTERVENTION Intensive insulin therapy was initiated perioperatively or postoperatively with a target glucose range of 4.4 to 6.1 mmol/L. MAIN OUTCOME MEASURES Adverse events from any cause during postoperative hospital stay were compared. RESULTS In the whole cohort, perioperatively initiated TGC markedly reduced the number of postoperative complications (23.2% vs 34.1%, 95% confidence interval [CI], 0.60-0.78) despite only minimal improvement in glucose control (blood glucose, 6.6 ± 0.7 vs 6.7 ± 0.8 mmol/L, P < .001; time in target range, 39.3% ± 13.7% vs 37.3% ± 13.8%, P < .001). The positive effects of TGC on postoperative complications were driven by nondiabetic subjects (21.3% vs 33.7%, 95% CI, 0.54-0.74; blood glucose 6.5 ± 0.6 vs 6.6 ± 0.8 mmol/L, not significant; time in target range, 40.8% ± 13.6% vs 39.7% ± 13.8%, not significant), whereas no significant effect was seen in diabetic patients (29.4% vs 35.1%, 95% CI, 0.66-1.06) despite significantly better glucose control in the perioperative group (blood glucose, 6.9 ± 1.0 vs 7.1 ± 0.8 mmol/L, P < .001; time in target range, 34.3% ± 12.7% vs 30.8% ± 11.5%, P < .001). CONCLUSIONS Perioperative initiation of intensive insulin therapy during cardiac surgery reduces postoperative morbidity in nondiabetic patients while having a minimal effect in diabetic subjects.

The influence of deep hypothermia on inflammatory status, tissue hypoxia and endocrine function of adipose tissue during cardiac surgery

Changes in endocrine function of adipose tissue during surgery, such as excessive production of proinflammatory cytokines, can significantly alter metabolic response to surgery and worsen its outcomes and prognosis of patients. Therapeutic hypothermia has been used to prevent damage connected with perioperative ischemia and hypoperfusion. The aim of our study was to explore the influence of deep hypothermia on systemic and local inflammation, adipose tissue hypoxia and adipocytokine production. We compared serum concentrations of proinflammatory markers (CRP, IL-6, IL-8, sIL-2R, sTNFRI, PCT) and mRNA expression of selected genes involved in inflammatory reactions (IL-6, TNF-α, MCP-1, MIF) and adaptation to hypoxia and oxidative stress (HIF1-α, MT3, GLUT1, IRS1, GPX1, BCL-2) in subcutaneous and visceral adipose tissue and in isolated adipocytes of patients undergoing cardiosurgical operation with hypothermic period. Deep hypothermia significantly delayed the onset of surgery-related systemic inflammatory response. The relative gene expression of the studied genes was not altered during the hypothermic period, but was significantly changed in six out of ten studied genes (IL-6, MCP-1, TNF-α, HIF1-α, GLUT1, GPX1) at the end of surgery. Our results show that deep hypothermia suppresses the development of systemic inflammatory response, delays the onset of local adipose tissue inflammation and thus may protect against excessive expression of proinflammatory and hypoxia-related factors in patients undergoing elective cardiac surgery procedure.

The effect of adjusting tracheal tube cuff pressure during deep hypothermic circulatory arrest: a randomised trial.

BACKGROUND Regular endotracheal tube cuff monitoring may prevent silent aspiration. OBJECTIVES We hypothesised that active management of the cuff of the tracheal tube during deep hypothermic cardiac arrest would reduce silent subglottic aspiration. We also determined to study its effect on postoperative mechanical ventilation and the incidence of postoperative positive tracheal cultures. DESIGN A randomised clinical trial. SETTING The study was conducted in a University Teaching Hospital from September 2008 to November 2009. PATIENTS Twenty-four patients undergoing elective pulmonary endarterectomy were included in the study. INTERVENTION After induction of general anaesthesia and tracheal intubation, the cuff of the tracheal tube was inflated to 25 cmH2O. Following this, 1 ml of methylene blue dye diluted in 2 ml of physiological saline was injected into the hypopharynx. Patients were randomly assigned to active cuff management during cooling and warming (where cuff pressure was monitored and the cuff was reinflated if it dropped below 20 cmH2O, or deflated if pressure exceeded 30 cmH2O) or passive monitoring (where cuff pressure was monitored but volume was not altered). Before weaning from cardiopulmonary bypass, fibreoptic bronchoscopy was performed. Silent aspiration was then diagnosed if blue dye was seen in the trachea below the cuff of the tube. MAIN OUTCOME MEASURES The primary aim of this study was to determine the incidence of silent aspiration. Secondary outcomes included duration of postoperative mechanical ventilation of the lungs and incidence of positive culture of tracheal aspirate. RESULTS Active cuff management patients were younger than controls (51.2 ± 11.6 vs. 63.2 ± 9 years, P = 0.028), but otherwise the two groups were similar. The primary endpoint was reached because we showed that silent aspiration was significantly less frequent in the study group (0/12 vs. 8/12 patients, P = 0.001). Significantly lower intracuff pressures were measured in the control group patients at several timepoints during cooling, just before hypothermic arrest and at all timepoints during rewarming. CONCLUSION We recommend that the cuff of the tracheal tube should be checked regularly during surgery under deep hypothermia, and the cuff pressure adjusted as required.

Glucose Control in the ICU Is There a Time for More Ambitious Targets Again

During the last 2 decades, the treatment of hyperglycemia in critically ill patients has become one of the most discussed topics in the intensive medicine field. The initial data suggesting significant benefit of normalization of blood glucose levels in critically ill patients using intensive intravenous insulin therapy have been challenged or even neglected by some later studies. At the moment, the need for glucose control in critically ill patients is generally accepted yet the target glucose values are still the subject of ongoing debates. In this review, we summarize the current data on the benefits and risks of tight glucose control in critically ill patients focusing on the novel technological approaches including continuous glucose monitoring and its combination with computer-based algorithms that might help to overcome some of the hurdles of tight glucose control. Since increased risk of hypoglycemia appears to be the major obstacle of tight glucose control, we try to put forward novel approaches that may help to achieve optimal glucose control with low risk of hypoglycemia. If such approaches can be implemented in real-world practice the entire concept of tight glucose control may need to be revisited.

A rationale for early extracorporeal membrane oxygenation in patients with postinfarction ventricular septal rupture complicated by cardiogenic shock: ECMO in patients with ventricular septal rupture

Ventricular septal rupture (VSR) became a rare mechanical complication of myocardial infarction in the era of percutaneous coronary interventions but is associated with extreme mortality in patients who present with cardiogenic shock (CS). Promising outcomes have been reported with the use of circulatory support allowing haemodynamic stabilization, followed by delayed repair. Therefore, we analysed our experience with an early use of Veno‐Arterial Extracorporeal Membrane Oxygenation (V‐A ECMO) for postinfarction VSR.

Use of high-thoracic epidural analgesia in pulmonary endarterectomy: a randomized feasibility study.

BACKGROUND The suitability of combined high-thoracic epidural anesthesia for pulmonary endarterectomy was studied. METHODS A prospective randomized clinical study was conducted in a university medical center from November 2005 to December 2006. The primary endpoint of this study was to evaluate perioperative hemodynamic data; secondary endpoints were to evaluate the duration of artificial ventilation, length of stay in the intensive care unit, and the impact on postoperative morbidity and mortality. RESULTS The 16 patients in the study group received high-thoracic epidural anesthesia plus general anesthesia; the 16 control patients received total intravenous anesthesia alone. Hemodynamic parameters and drug use, as well as the time to extubation, rate of complications, postoperative pain, the length of intensive care unit stay, and mortality, were recorded. The 2 groups were comparable with respect to hemodynamic stability during induction of anesthesia. The study group patients had significantly lower sufentanil consumption (mean +/- SD, 2.1 +/- 0.7 microg/kg versus 9.1 +/- 3.1 microg/kg; P <.001), a shorter period of artificial ventilation (34 +/- 35 hours versus 52 +/- 49 hours; P = .0318), and lower postoperative pain scores at 3 hours (0.10 +/- 0.26 versus 0.93 +/- 1.38; P = .015), 12 hours (0.14 +/- 0.53 versus 0.93 +/- 0.79; P = .002), and 24 hours (0.35 +/- 0.49 versus 1.33 +/- 1.04; P = .007). CONCLUSIONS This study has shown that combined epidural and general anesthesia is a suitable anesthetic option in patients who are selected for pulmonary endarterectomy. It provides hemodynamic stability and reduces the duration of tracheal intubation postoperatively and improves postoperative pain relief, although this option has not been shown to decrease either the length of the intensive care unit stay or mortality.

The effect of continuous exenatide infusion on cardiac function and perioperative glucose control in cardiac surgery patients: a single-blind, randomized, controlled trial

We performed a randomized controlled trial with the glucagon‐like peptide‐1 (GLP‐1) receptor agonist exenatide as add‐on to standard peri‐operative insulin therapy in patients undergoing elective cardiac surgery. The aims of the study were to intensify peri‐operative glucose control while minimizing the risk of hypoglycaemia and to evaluate the suggested cardioprotective effects of GLP‐1‐based treatments. A total of 38 patients with decreased left ventricular systolic function (ejection fraction ≤50%) scheduled for elective coronary artery bypass grafting (CABG) were randomized to receive either exenatide or placebo in a continuous 72‐hour intravenous (i.v.) infusion on top of standard peri‐operative insulin therapy. While no significant difference in postoperative echocardiographic variables was found between the groups, participants receiving exenatide showed improved peri‐operative glucose control as compared with the placebo group (average glycaemia 6.4 ± 0.5 vs 7.3 ± 0.8 mmol/L; P < .001; percentage of time in target range of 4.5–6.5 mmol/L 54.8% ± 14.5% vs 38.6% ± 14.4%; P = .001; percentage of time above target range 39.7% ± 13.9% vs 52.8% ± 15.2%; P = .009) without an increased risk of hypoglycaemia (glycaemia <3.3 mmol/L: 0.10 ± 0.32 vs 0.21 ± 0.42 episodes per participant; P = .586). Continuous administration of i.v. exenatide in patients undergoing elective CABG could provide a safe option for intensifying the peri‐operative glucose management of such patients.

High thoracic epidural anaesthesia and analgesia in cardiac surgery - a retrospective study: P-91

General Teaching Hospital, 1st Medical Faculty, Charles University, Prague, Czech Republic Introduction: According to many studies high thoracic epidural anaesthesia (TEA) offers many advantages over general anaesthesia in patients undergoing cardiac surgery [1,2]. On the contrary there is still an awareness of possible epidural haematoma formation with serious neurological consequences [3]. Studies concerning this problem are heterogeneous and refer to about 6000 patients altogether. Because of more than ten years experience with TEA we have decided to determine the risk of serious neurological complications associated with TEA. Method: A single centre has performed a retrospective analysis of its patients who underwent cardiac surgery from 1995 to 2002. Primary end point was an incidence of spinal cord compression such as radicular back pain or progressive neurological deficit in patients who had cardiac surgery under combined general and TEA. A secondary end point was an incidence of combined unfavourable events. A comparison of outcome between the groups of patients with TEA and balanced anaesthesia was carried out. Results: Records from 3966 patients were analysed. 1519 of them underwent cardiac surgery with TEA and 2447 patients were operated on using balanced general anaesthesia. Anaesthesia – analgesia 35

X-ray indices of chest drain malposition after insertion for drainage of pneumothorax in mechanically ventilated critically ill patients

Background Chest drain (CD) migration in the pleural cavity may result in inadequate drainage of pneumothorax. The aim of this study was to assess several parameters that might help in diagnosing CD migration on chest X-ray (CXR). Methods Patients with a CD inserted from the safe triangle with a subsequent supine CXR and CT scan performed less than 24 hours apart were assessed for CD foreshortening, angle of inclination of the CD, and CD tortuosity. CD foreshortening was expressed as a ratio between CD length measured in coronal plane only and CD length inside the pleural cavity measured on CT. The angle of inclination of the CD was measured as the angle between the horizontal line and CD at the pleural space entry on CXR. CD tortuosity was calculated as a ratio between the distance from CD pleural space entry to the tip of the CD and the length of CD from the pleural space entry to its tip on CXR. Results Altogether 28 patients were included in the study. The median time between the CXR and CT examinations was 5.4 hours (IQR, 3.8-6.9 hours). CD foreshortening was the best clue of a misplaced CD with AUC of 0.93, 100% sensitivity and 88% specificity for a cut-off value of 82%. The angle of CD inclination was greater in patients with misplaced CD with AUC of 0.83, 75% sensitivity and 92% specificity for a cut-off of 50 degrees. The performance of CD tortuosity was poor. Conclusions Greater foreshortening of the CD and a steep angle of inclination of the CD above the horizontal at chest entry should raise suspicion of CD migration and mandate further investigation by chest ultrasound to rule out residual pneumothorax occult on CXR.