Prospective validation of the EuroSCORE II risk model in a single Dutch cardiac surgery centre.

OBJECTIVE: The EuroSCORE I was one of the most frequently used pre-operative risk models in cardiac surgery. In 2011 it was replaced by its successor the EuroSCORE II. This study aims to validate the EuroSCORE II and to compare its performance with the EuroSCORE I in a Dutch hospital. METHODS: The EuroSCORE II was prospectively validated in 2,296 consecutive cardiac surgery patients between 1 April 2012 and 1 January 2014. Receiver operating characteristic curves on in-hospital mortality were plotted for EuroSCORE I and EuroSCORE II, and the area under the curve was calculated to assess discriminative power. Calibration was assessed by comparing observed versus expected mortality. Additionally, analyses were performed in which we stratified for type of surgery and for elective versus emergency surgery. RESULTS: The observed mortality was 2.4% (55 patients). The discriminative power of the EuroSCORE II surpassed that of the EuroSCORE I (area under the curve EuroSCORE II 0.871, 95% confidence interval (CI) 0.832-0.911; area under the curve additive EuroSCORE I 0.840, CI 0.798-0.882; area under the curve logistic EuroSCORE I 0.761, CI 0.695-0.828). Both the additive and the logistic EuroSCORE I overestimated mortality (predictive mortality additive EuroSCORE I median 5.0%, inter-quartile range 3.0-8.0%; logistic EuroSCORE I 10.7%, inter-quartile range 5.8-13.9), while the EuroSCORE II underestimated mortality (median 1.6%, inter-quartile range 1.0-3.5). In most stratified analyses the EuroSCORE II performed better. CONCLUSION: Our results show that the EuroSCORE II produces a valid risk prediction and outperforms the EuroSCORE I in elective cardiac surgery patients.

Long-term outcomes and cost effectiveness of high-dose dexamethasone for cardiac surgery: a randomised trial.

Prophylactic intra-operative administration of dexamethasone may improve short-term clinical outcomes in cardiac surgical patients. The purpose of this study was to evaluate long-term clinical outcomes and cost effectiveness of dexamethasone versus placebo. Patients included in the multicentre, randomised, double-blind, placebo-controlled DExamethasone for Cardiac Surgery (DECS) trial were followed up for 12 months after their cardiac surgical procedure. In the DECS trial, patients received a single intra-operative dose of dexamethasone 1 mg.kg-1 (n = 2239) or placebo (n = 2255). The effects on the incidence of major postoperative events were evaluated. Also, overall costs for the 12-month postoperative period, and cost effectiveness, were compared between groups. Of 4494 randomised patients, 4457 patients (99%) were followed up until 12 months after surgery. There was no difference in the incidence of major postoperative events, the relative risk (95%CI) being 0.86 (0.72-1.03); p = 0.1. Treatment with dexamethasone reduced costs per patient by £921 [€1084] (95%CI £-1672 to -137; p = 0.02), mainly through reduction of postoperative respiratory failure and duration of postoperative hospital stay. The probability of dexamethasone being cost effective compared with placebo was 97% at a threshold value of £17,000 [€20,000] per quality-adjusted life year. We conclude that intra-operative high-dose dexamethasone did not have an effect on major adverse events at 12 months after cardiac surgery, but was associated with a reduction in costs. Routine dexamethasone administration is expected to be cost effective at commonly accepted threshold levels for cost effectiveness.

Safety challenges of medical equipment in nurse anaesthetist training in Haiti.

Safety challenges related to the use of medical equipment were investigated during the training of nurse anaesthetists in Haiti, using a systems approach to Human Factors and Ergonomics (HFE). The Observable Performance Obstacles tool, based on the Systems Engineering Initiative for Patient Safety (SEIPS) model, was used in combination with exploratory observations during 13 surgical procedures, to identify performance obstacles created by the systemic interrelationships of medical equipment. The identification of performance obstacles is an effective way to study the accumulation of latent factors and risk hazards, and understand its implications in practice and behaviour of healthcare practitioners. In total, 123 performance obstacles were identified, of which the majority was related to environmental and organizational aspects. These findings show how the performance of nurse anaesthetists and their relation to medical equipment is continuously affected by more than user-related aspects. The contribution of systemic performance obstacles and coping strategies to enrich system design interventions and improve healthcare system is highlighted. In addition, methodological challenges of HFE research in low-resource settings related to professional culture and habits, and the potential of community ergonomics as a problem-managing approach are described.

Clinical evaluation of a new tracheal impedance cardiography method.

Non-invasive cardiac output measurement by means of impedance cardiography has been evaluated before, and agreement with other methods has been variable. We decided to study a newly developed tracheal impedance device, that is claimed to be more accurate and reliable. This incorporates new software and mathematical formulae, that are designed to reduce signal noise from diathermy, leading to improved accuracy. In 25 cardiothoracic surgery patients, simultaneous measurements were performed using both pulmonary artery thermodilution and the tracheal impedance device, at five peri-operative time points: before skin incision; after weaning from cardiopulmonary bypass; after sternal closure; and 30 min and 2 h after arrival in the intensive care unit. Mean cardiac output, bias and 95% limits of agreement were 5.3, 0.03 and -2.8 to 2.8 l.min(-1) , respectively. Tracheal impedance showed good correlation with measurement trends using thermodilution in 88% of measurements, with a mean (95% limit of agreement) angular bias of -9.0° (-83.3 to 65.3°). However, the wide limits of agreement and high percentage error of 53% that were apparent in this study mean that, in its present guise, tracheal impedance is not an acceptable alternative to thermodilution in cardiac surgical patients.

Diagnostic accuracy of modified transoesophageal echocardiography for pre-incision assessment of aortic atherosclerosis in cardiac surgery patients.

BACKGROUND: Epiaortic ultrasound scanning (EUS) is regarded as the reference standard for detecting atherosclerosis in the ascending aorta (AA). Combined with appropriate surgical modifications, EUS use can significantly reduce the incidence of postoperative stroke when detecting severe AA atherosclerosis. A recently introduced modification of conventional transoesophageal echocardiography (TOE), known as the A-View method, has proven capable of inspecting the distal AA. The objective of this study was to quantify the diagnostic accuracy of modified TOE in assessing atherosclerosis of the distal AA. METHODS: After approval by the institutional medical ethical committee and after obtaining written informed consent, 465 consecutive patients above 65 yr old, undergoing elective cardiac surgery with a median sternotomy, were included. The study followed a cross-sectional diagnostic design. All consecutive patients underwent modified TOE followed by EUS (reference standard) to assess the severity of distal AA atherosclerosis. We constructed contingency tables to compare the presence (and severity) of atherosclerosis, detected by the two techniques. RESULTS: The positive predictive value of modified TOE for the detection of clinically significant atherosclerosis was 67%, and the negative predictive value was 97%. The sensitivity was 95% and the specificity was 79%. One patient suffered a pulmonary haemorrhage, although he recovered without further sequelae. We did not observe any clinical significant haemodynamic or ventilatory effects. CONCLUSIONS: The high negative predictive value and sensitivity show that modified TOE yields adequate diagnostic accuracy for excluding clinically relevant aorta atherosclerosis without significant cardiopulmonary side-effects, provided that the A-View catheter is introduced carefully.

Safety of cardiac surgery without blood transfusion: a retrospective study in Jehovah's Witness patients.

The aim of this retrospective study was to compare the utilisation of blood products and outcomes following cardiac surgery for 123 Jehovah's Witnesses and 4219 non-Jehovah's Witness patient controls. The study took place over a 7-year period at the Amphia Hospital in Breda, the Netherlands. A specific protocol was used in the management of Jehovah's Witness patients, while the control group received blood without restriction according to their needs. Patients' characteristics were comparable in both groups. Pre-operatively, the mean (SD) Euro Score was higher in the Jehovah's Witness group (3.2 (2.6) vs 2.7 (2.5), respectively; p < 0.02). Pre-operative haemoglobin concentration was higher in the Jehovah's Witness group (8.9 (0.7) vs 8.6 (0.9) g.dl(-1), respectively; p < 0.001). The total cardiopulmonary bypass time did not differ between groups. The requirement for allogenic blood transfusion was 0% in the Jehovah's Witness group compared to 65% in the control group. Postoperatively, there was a lower incidence of Q-wave myocardial infarction (2 (1.8%) vs 323 (7.7%), respectively; p < 0.02), and non Q-wave infarction (11 (9.8%) vs 559 (13.2%), respectively; p < 0.02) in the Jehovah's Witness group compared with controls. Mean (SD) length of stay in the intensive care unit (2.3 (3.2) vs 2.6 (4.2) days; p = 0.26), re-admission rate to the intensive care unit (5 (4.5%) vs 114 (2.7%); p = 0.163), and mortality (3 (2.7%) vs 65 (1.5%); p = 0.59), did not differ between the Jehovah's Witness and control groups, respectively.

Effect of sevoflurane on the ex vivo secretion of TNF-alpha during and after coronary artery bypass surgery.

BACKGROUND AND OBJECTIVE: Sevoflurane has been used for the induction and maintenance of anaesthesia during cardiac surgery owing to its favourable haemodynamic effects. It has been suggested that it offers protection against myocardial ischaemia-reperfusion injury. METHODS: We investigated the effect of sevoflurane on plasma concentrations of tumour necrosis factor-alpha (TNF-alpha) after ex vivo stimulation of whole-blood leukocytes by lipopolysaccharide from 20 patients undergoing coronary artery bypass surgery. The patients were randomized to two groups. Group 1 patients were induced and maintained with sevoflurane; those in Group 2 were anaesthetized with moderate doses of midazolam-sufentanil. Blood samples were drawn from the patients on seven occasions from before induction of anaesthesia until 24 h after skin closure. RESULTS: Plasma concentrations of TNF-alpha were lower in Group 1 than in Group 2 after cessation of cardiopulmonary bypass (median (interquartiles): 25 (21-30) versus 37 (28-79) pg mL(-1); P < 0.05) and 24h after skin closure (196 (100-355) versus 382 (233-718) pg mL(-1); P < 0.05). Postoperatively, two cases of myocardial infarction were recorded, one in each group. Six patients in Group 2 needed continued inotropic support after the first morning to maintain haemodynamic stability versus one patient in Group 1 (P < 0.05). The length of stay in the intensive care unit was significantly lower in Group 1 than in Group 2 (mean +/- SD: 25 +/- 16 versus 54 +/- 30 h; P < 0.05). CONCLUSIONS: Sevoflurane reduces production of TNF-alpha more than total intravenous anaesthesia with midazolam-sufentanil during cardiac surgery. This may reduce cardiac morbidity and the length of stay in the intensive care unit.

Effect of VIMA with sevoflurane versus TIVA with propofol or midazolam-sufentanil on the cytokine response during CABG surgery.

BACKGROUND AND OBJECTIVE: Cardiac surgery with cardiopulmonary bypass triggers an inflammatory response involving pro-inflammatory cytokines such as tumour necrosis factor-alpha (TNF-alpha), interleukin 6 (IL-6) and interleukin 8 (IL-8). We investigated whether different anaesthetic techniques alter the pro-inflammatory cytokine response to cardiac surgery. METHODS: Thirty patients scheduled for elective coronary artery bypass grafting (CABG) surgery were randomized into three groups of 10 patients. They received either volatile inhalation induction and maintenance (Group 1) or total intravenous anaesthesia with propofol and a minimal dose sufentanil (Group 2) or a moderate dose midazolam-sufentanil (Group 3). The effect of the different anaesthetic techniques on plasma levels of TNF-alpha, IL-6 and IL-8 were examined during and after anaesthesia. RESULTS: Concentrations of TNF-alpha, and IL-8 were comparable in the three groups throughout all measurements. Before the start of cardiopulmonary bypass, IL-6 was significantly higher in Group 1 than in Group 2 (P = 0.009) or Group 3 (P = 0.030), but there were no differences between groups after cardiopulmonary bypass or postoperatively. In the three groups there was a positive correlation between aortic clamping time and serum concentrations of IL-6 (r = 0.54) and IL-8 (r = 0.62). Length of stay in intensive care was correlated with high levels of TNF-alpha (r = 0.78). CONCLUSIONS: Albeit there is difference between the volatile induction and maintenance of the anaesthesia method and the total intravenous anaesthesia technique on the pro-inflammatory cytokine response to surgical stimulation before starting of cardiopulmonary bypass, neither technique can modify the pro-inflammatory cytokine response to ischaemia-reperfusion or extracorporeal circulation.

Dexamethasone decreases the pro- to anti-inflammatory cytokine ratio during cardiac surgery.

BACKGROUND: Cytokines regulate inflammation associated with cardiopulmonary bypass (CPB). Pro-inflammatory cytokines may cause myocardial dysfunction and haemodynamic instability after CPB, but the release of anti-inflammatory cytokines is potentially protective. We studied the effects of dexamethasone on pro- and anti-inflammatory cytokine responses during coronary artery bypass grafting surgery. METHODS: Seventeen patients were studied: nine patients received dexamethasone 100 mg before induction of anaesthesia (group 1) and eight patients acted as controls (group 2). Plasma levels of tumour necrosis factor (TNF)-alpha, interleukin (IL)-6, IL-8, IL-10 and IL-4 were measured perioperatively. RESULTS: TNF-alpha and IL-8 did not increase significantly in group 1 whereas they increased in group 2 to greater than preoperative values (P<0.05). IL-6 increased in both groups, with lower values in group 1 than in group 2 (P<0.05). IL-10 increased in both groups, with higher values in group 1 (P<0.05). IL-4 did not change in group 1 but decreased in group 2 compared with pre-induction values (P<0.05). After surgery, patients in group 2 had tachycardia, hyperthermia, a greater respiratory rate and higher pulmonary artery pressure, and a longer stay in the intensive care unit. CONCLUSION: Dexamethasone given before cardiac surgery changes circulating cytokines in an anti-inflammatory direction. Postoperative outcome may be improved by inhibition of the systemic inflammatory response.

Liver and renal function after volatile induction and maintenance of anesthesia (VIMA) with sevoflurane versus TIVA with sufentanil-midazolam for CABG surgery.

We compared liver and renal function after volatile induction and maintenance of anesthesia (VIMA) with sevoflurane and minimal dose sufentanil versus total intravenous anesthesia (TIVA) with moderate dose of midazolam and sufentanil in patients undergoing CABG surgery. Eighty nine patients were studied retrospectively after VIMA (44 patients) or after TIVA (45 patients). Liver and renal function were measured before (T0), then 1 (T1), 2 (T2), 5 (T3) days and 6 weeks (T4) after the operation. Serum levels of aspartate aminotransferase (ASAT) and lactate dehydrogenase (LDH) increased in both groups at T1, T2 and T3 and the highest levels were at T1. Levels of total bilirubin (TBil) increased at T1 only in the TIVA group. Levels of g-glutamyl transpeptidase (GGT) and alanine aminotransferase (ALAT), increased in both groups at T3. Serum levels of creatinine (Cr) were high in both groups on T1 and T2. Blood urea nitrogen (BUN) was high in both group at T2, and T3 with the peak levels in T2. Six weeks after the operation all liver and renal functions were normal in both groups. We concluded that VIMA with sevoflurane during cardiac surgery has no untoward effects on liver or renal functions. The transient reversible elevation was comparable in the VIMA and TIVA groups which was most probably due to the effect of the operation itself.

Postcardiac surgery low cardiac output syndrome: dopexamine or dopamine?

OBJECTIVE: To compare the efficacy and safety of dopexamine with dopamine in the treatment of low cardiac output syndrome after cardiac surgery. DESIGN: This was a multicentre, double-blind, randomised, parallel-group study conducted in intensive care units at centres in Holland and Belgium. Patients were randomised to receive dopexamine (up to 2.0 micrograms/ kg per min) or dopamine (up to 6.0 micrograms/kg per min) for 6 h after low cardiac output syndrome was confirmed. RESULTS: 70 patients were enrolled (35/group) and there was no significant differences in the operative procedures or haemodynamics at entry into the study. Clinical efficacy, defined as a cardiac index > 2.5 l/min per m2 with urine production > 0.5 ml/kg per h and stable haemodynamics for two consecutive readings 1 h apart, was achieved by 90 and 87% of patients in the dopexamine and dopamine groups, respectively. However, more patients maintained clinical efficacy over the 6-h period in the dopexamine group, which was statistically significant at 1-2 h and approached significance at all other time points. Safety was assessed by comparing the adverse events and concomitant medication. Fewer patients on dopexamine had cardiac events compared with dopamine-treated patients (25 vs 38 events), although there was no difference in the pattern of rhythm disturbance. Fewer patients in the dopexamine group required concomitant vasodilating drugs (18 vs 30). CONCLUSION: Taking the proportion of patients achieving clinical efficacy, the time to achieve it and the maintenance of it along with the adverse event profile, dopexamine was shown to be an effective and safe drug to use in the management of low cardiac output syndrome after coronary artery bypass graft surgery and may be superior to dopamine.

Oral antimony intoxications in man.

Four cases of acute oral antimony intoxication are reported. Three patients survived without sequelae. One patient, a 93-yr-old male, died from multiple organ failure. Toxicological analysis of blood, urine, and tissues revealed a severe intoxication.

Dopexamine hydrochloride after coronary artery bypass grafting.

Dopexamine hydrochloride, a dopamine analog with specific beta 2 adrenergic and DA1 dopaminergic receptor activity, was evaluated in a prospective study including 20 patients undergoing coronary artery bypass grafting. Shortly after admission to the intensive care unit, increasing doses of dopexamine hydrochloride (1.0, 2.0, 4.0, 6.0, 8.0 and 10.0 micrograms/kg/min) were administered as continuous infusion at 20-minute intervals. Hemodynamic monitoring revealed that dopexamine hydrochloride causes a significant decrease in systemic vascular resistance and a significant increase in cardiac output and heart rate, even at lower dose levels (1.0 micrograms/kg/min). At higher dose levels (greater than or equal to 2.0 micrograms/kg/min), adverse effects such as systolic hypertension and tachycardia were observed. Shunt fraction increased significantly during dopexamine hydrochloride administration, probably due to the increase in cardiac output. It is concluded that dopexamine hydrochloride is a potent vasodilating agent at lower dose levels and is of potential benefit to patients with compromised myocardial function after coronary artery bypass grafting. Higher dose levels may cause unwanted side effects, which might be explained by various mechanisms such as norepinephrine uptake inhibition.

Epidural sufentanil for intra- and postoperative analgesia in thoracic surgery: a comparative study with intravenous sufentanil.

A comparative study was undertaken to evaluate the effectiveness of epidural sufentanil in providing intra- and postoperative analgesia during thoracic surgery. Sufentanil was chosen on the basis of its high lipid solubility and its potent opiate receptor binding. Epidural sufentanil was compared with intravenous sufentanil as the major intraoperative analgetic agent in an anesthesia regimen with midazolam and nitrous oxide. Epidural sufentanil significantly decreased the need for supplementary intravenous analgesia. In the epidural sufentanil group the immediate postoperative analgesia was found to be better, with a longer duration of action, compared with the intravenous sufentanil group. Postoperatively epidural sufentanil was compared with epidural morphine. Sufentanil provided good analgesia with a very fast onset and a mean duration of almost 7 h. Severe respiratory depression was observed in one patient within 1 h of extubation, probably due to the combined effects of the narcotic administration and residual midazolam. It is concluded that 50 micrograms of sufentanil administered in the thoracic epidural space provides valuable intraoperative analgesia which can easily be extended into the postoperative period, although all necessary precautions for epidural opiate administration should be taken.