[Handovers during anaesthetic care can be further improved]. / Anesthesiologische overdracht op de OK kan nog beter.

In 2005, the Dutch Society of Anaesthesiologists showed that handovers during anaesthetic care increase complication and mortality rates, an observation that has recently been confirmed by a Canadian study. In contrast to surgical care, handovers in anaesthetic care are quite common for various reasons including end of shift, tiredness after night duty, and activities outside the operating centre. The quality of handovers could be improved by training on an anaesthesia simulator, with emphasis on communication, reduction of information loss and using checklists.

[Inhalational or intravenous anesthesia?]. / Algehele anesthesie: inhaleren of injecteren?

The debate continues whether there is a difference in patient outcome following inhalational versus intravenous anesthesia. A recent meta-analysis showed improved outcome following inhalational anesthesia in patients undergoing cardiac surgery but not in patients undergoing non-cardiac procedures. In this article we discuss the meta-analysis and its caveats, taking into account additional comparative studies. Our overall conclusion is that it is too early to definitively claim that one anesthesia technique results in a better outcome than the other.

Non-invasive continuous arterial pressure and pulse pressure variation measured with Nexfin(®) in patients following major upper abdominal surgery: a comparative study.

We compared the accuracy and precision of the non-invasive Nexfin(®) device for determining systolic, diastolic, mean arterial pressure and pulse pressure variation, with arterial blood pressure values measured from a radial artery catheter in 19 patients following upper abdominal surgery. Measurements were taken at baseline and following fluid loading. Pooled data results of the arterial blood pressures showed no difference between the two measurement modalities. Bland-Altman analysis of pulse pressure variation showed significant differences between values obtained from the radial artery catheter and Nexfin finger cuff technology (mean (SD) 1.49 (2.09)%, p < 0.001, coefficient of variation 24%, limits of agreement -2.71% to 5.69%). The effect of volume expansion on pulse pressure variation was identical between methods (concordance correlation coefficient 0.848). We consider the Nexfin monitor system to be acceptable for use in patients after major upper abdominal surgery without major cardiovascular compromise or haemodynamic support.

The effect of propofol on haemodynamics: cardiac output, venous return, mean systemic filling pressure, and vascular resistances.

BACKGROUND: Although arterial hypotension occurs frequently with propofol use in humans, its effects on intravascular volume and vascular capacitance are uncertain. We hypothesized that propofol decreases vascular capacitance and therefore decreases stressed volume. METHODS: Cardiac output (CO) was measured using Modelflow(®) in 17 adult subjects after upper abdominal surgery. Mean systemic filling pressure (MSFP) and vascular resistances were calculated using venous return curves constructed by measuring steady-state arterial and venous pressures and CO during inspiratory hold manoeuvres at increasing plateau pressures. Measurements were performed at three incremental levels of targeted blood propofol concentrations. RESULTS: Mean blood propofol concentrations for the three targeted levels were 3.0, 4.5, and 6.5 µg ml(-1). Mean arterial pressure, central venous pressure, MSFP, venous return pressure, Rv, systemic arterial resistance, and resistance of the systemic circulation decreased, stroke volume variation increased, and CO was not significantly different as propofol concentration increased. CONCLUSIONS: An increase in propofol concentration within the therapeutic range causes a decrease in vascular stressed volume without a change in CO. The absence of an effect of propofol on CO can be explained by the balance between the decrease in effective, or stressed, volume (as determined by MSFP), the decrease in resistance for venous return, and slightly improved heart function. CLINICAL TRIAL REGISTRATION: Netherlands Trial Register: NTR2486.

Cardiospecific sevoflurane treatment quenches inflammation but does not attenuate myocardial cell damage markers: a proof-of-concept study in patients undergoing mitral valve repair.

BACKGROUND: Inflammation is considered a key mediator of complications after cardiac surgery. Sevoflurane has been shown to quench inflammation and to provide cardioprotection in preclinical studies. Clinical studies using sevoflurane confirm this effect on inflammation but do not consistently show clinical benefits. This paradox may indicate that the contribution of inflammation to postoperative sequalae is less than commonly thought or that systemic doses are too low in their local concentration. To test the latter, we evaluated the effects of intramyocardial sevoflurane delivery. METHODS: Selective myocardial sevoflurane delivery was performed during aortic cross-clamping in patients undergoing valve surgery (n=11). Results were compared with a control group not receiving sevoflurane (n=10). A reference group (n=5) was added to evaluate the effects of systemic sevoflurane delivery. Paired arterial and myocardial venous blood samples were collected at various time points post-reperfusion. Inflammatory mediators and myocardial cell damage were studied. RESULTS: Intramyocardial delivery was superior to systemic delivery in attenuation of interleukin-6 and interleukin-8 (-44% and -25%, respectively; both P=0.001). Myocardial and systemic sevoflurane delivery effectively suppressed surgery-related inflammatory responses including postoperative C-reactive protein levels when compared with controls [63 (47-99) (P=0.01) and 58 (56-81) (P=0.04) compared with 107 (79-144) mg litre(-1)]. Sevoflurane treatment did not reduce postoperative troponin T, creatine kinase, and creatine kinase-MB values. CONCLUSIONS: This proof-of-concept study suggests that intramyocardial delivery compared with the systemic delivery of sevoflurane more strongly attenuates the systemic inflammatory response after cardiopulmonary bypass without reducing postoperative markers of myocardial cell damage. CLINICAL TRIAL REGISTRATION: Nederlands Trial Register NTR2089.

Evaluation of surgical conditions during laparoscopic surgery in patients with moderate vs deep neuromuscular block.

BACKGROUND: The routine use of neuromuscular blocking agents reduces the occurrence of unacceptable surgical conditions. In some surgeries, such as retroperitoneal laparoscopies, deep neuromuscular block (NMB) may further improve surgical conditions compared with moderate NMB. In this study, the effect of deep NMB on surgical conditions was assessed. METHODS: Twenty-four patients undergoing elective laparoscopic surgery for prostatectomy or nephrectomy were randomized to receive moderate NMB (train-of-four 1-2) using the combination of atracurium/mivacurium, or deep NMB (post-tetanic count 1-2) using high-dose rocuronium. After surgery, NMB was antagonized with neostigmine (moderate NMB), or sugammadex (deep NMB). During all surgeries, one surgeon scored the quality of surgical conditions using a five-point surgical rating scale (SRS) ranging from 1 (extremely poor conditions) to 5 (optimal conditions). Video images were obtained and 12 anaesthetists rated a random selection of images. RESULTS: Mean (standard deviation) SRS was 4.0 (0.4) during moderate and 4.7 (0.4) during deep NMB (P<0.001). Moderate block resulted in 18% of scores at the low end of the scale (Scores 1-3); deep block resulted in 99% of scores at the high end of the scale (Scores 4 and 5). Cardiorespiratory conditions were similar during and after surgery in both groups. Between anaesthetists and surgeon, there was poor agreement between scores of individual images (average κ statistic 0.05). CONCLUSIONS: Application of the five-point SRS showed that deep NMB results in an improved quality of surgical conditions compared with moderate block in retroperitoneal laparoscopies, without compromise to the patients' peri- and postoperative cardiorespiratory conditions. Trial registration The study was registered at clinicaltrials.gov under number NCT01361149.

Upper thoracic epidural anaesthesia: effects of age on neural blockade and cardiovascular parameters.

BACKGROUND: Segmental dose reduction with increasing age after thoracic epidural anaesthesia (TEA) has been documented. We hypothesised that after a fixed loading dose of ropivacaine at the T3-T4 level, increasing age would result in more extended analgesic spread. In addition, other aspects of neural blockade and haemodynamic changes were studied. METHODS: Thirty-five lung surgery patients were included in three age groups. Thirty-one patients received an epidural catheter at the T3-T4 interspace followed by an injection of 8-ml ropivacaine 0.75%. Analgesia was assessed with pinprick and temperature discrimination. Motor block was tested using the Bromage and epidural scoring scale for arm movements score. An arterial line was inserted for invasive measurement of blood pressure, cardiac index (CI) and stroke volume (SV). RESULTS: There was no influence of age on quality of TEA except for the caudal border of analgesia being somewhat lower in the middle and older age group compared with the young age group. Heart rate (6.0 ± 5.9, P < 0.001), mean arterial pressure (16.1 ± 15.6, P < 0.001), CI (0.55 ± 0.49, P < 0.001) and SV (9.6 ± 14.6, P = 0.001) decreased after TEA for the total group. Maximal reduction in heart rate after TEA was more extensive in the young age group compared with the other age groups. There was no effect of age on other cardiovascular parameters. CONCLUSION: We were unable to demonstrate an effect of age on the maximal number of spinal segments blocked after TEA; however, the caudad spread of analgesia increased with advancing age. In addition, reduction of heart rate was greater in the youngest group.

Predicting cardiac output responses to passive leg raising by a PEEP-induced increase in central venous pressure, in cardiac surgery patients.

BACKGROUND: Changes in central venous pressure (CVP) rather than absolute values may be used to guide fluid therapy in critically ill patients undergoing mechanical ventilation. We conducted a study comparing the changes in the CVP produced by an increase in PEEP and stroke volume variation (SVV) as indicators of fluid responsiveness. Fluid responsiveness was assessed by the changes in cardiac output (CO) produced by passive leg raising (PLR). METHODS: In 20 fully mechanically ventilated patients after cardiac surgery, PEEP was increased +10 cm H2O for 5 min followed by PLR. CVP, SVV, and thermodilution CO were measured before, during, and directly after the PEEP challenge and 30° PLR. The CO increase >7% upon PLR was used to define responders. RESULTS: Twenty patients were included; of whom, 10 responded to PLR. The increase in CO by PLR directly related (r=0.77, P<0.001) to the increase in CVP by PEEP. PLR responsiveness was predicted by the PEEP-induced increase in CVP [area under receiver-operating characteristic (AUROC) curve 0.99, P<0.001] and by baseline SVV (AUROC 0.90, P=0.003). The AUROC's for dCVP and SVV did not differ significantly (P=0.299). CONCLUSIONS: Our data in mechanically ventilated, cardiac surgery patients suggest that the newly defined parameter, PEEP-induced CVP changes, like SVV, appears to be a good parameter to predict fluid responsiveness.

Cardiac assessment of patients with late stage Duchenne muscular dystrophy.

Background. Duchenne muscular dystrophy (DMD) patients used to die mainly from pulmonary problems. However, as advances in respiratory care increase life expectancy, mortality due to cardiomyopathy rises. Echocardiography remains the standard diagnostic modality for cardiomyopathy in DMD patients, but is hampered by scoliosis and poor echocardiographic acoustic windows in adult DMD patients. Multigated cardiac radionuclide ventriculography (MUGA) does not suffer from these limitations. N-terminal proBNP (NTproBNP) has shown to be a diagnostic factor for heart failure. We present our initial experience with plasma NT-proBNP measurement in the routine screening and diagnosis of cardiomyopathy in adult mechanically ventilated DMD patients.Methods. Retrospective study, 13 patients. Echocardiography classified left ventricular (LV) function as preserved or depressed. NT-proBNP was determined using immunoassay. LV ejection fraction (LVEF) was determined using MUGA.Results. Median (range) NT-proBNP was 73 (25 to 463) ng/l. Six patients had an NT-proBNP >125 ng/l. Seven patients showed an LVEF <45% on MUGA. DMD patients with depressed LV function (n=4) as assessed by echocardiography had significantly higher median NT-proBNP than those (n=9) with preserved LV function: 346 (266 to 463) ng/l versus 69 (25 to 257) ng/l (p=0.003). NT-proBNP significantly correlated with depressed LV function on echocardiogram and with LVEF determined by MUGA.Conclusion. Although image quality of MUGA is superior to echocardiography, the combination of echocardiography and NT-proBNP achieves similar results in the evaluation of left ventricular function and is less time consuming and burdensome for our patients. We advise to add NT-proBNP to echocardiography in the routine cardiac assessment of DMD patients. (Neth Heart J 2009;17:232-7.).

Decontamination of the digestive tract and oropharynx in ICU patients.

BACKGROUND: Selective digestive tract decontamination (SDD) and selective oropharyngeal decontamination (SOD) are infection-prevention measures used in the treatment of some patients in intensive care, but reported effects on patient outcome are conflicting. METHODS: We evaluated the effectiveness of SDD and SOD in a crossover study using cluster randomization in 13 intensive care units (ICUs), all in The Netherlands. Patients with an expected duration of intubation of more than 48 hours or an expected ICU stay of more than 72 hours were eligible. In each ICU, three regimens (SDD, SOD, and standard care) were applied in random order over the course of 6 months. Mortality at day 28 was the primary end point. SDD consisted of 4 days of intravenous cefotaxime and topical application of tobramycin, colistin, and amphotericin B in the oropharynx and stomach. SOD consisted of oropharyngeal application only of the same antibiotics. Monthly point-prevalence studies were performed to analyze antibiotic resistance. RESULTS: A total of 5939 patients were enrolled in the study, with 1990 assigned to standard care, 1904 to SOD, and 2045 to SDD; crude mortality in the groups at day 28 was 27.5%, 26.6%, and 26.9%, respectively. In a random-effects logistic-regression model with age, sex, Acute Physiology and Chronic Health Evaluation (APACHE II) score, intubation status, and medical specialty used as covariates, odds ratios for death at day 28 in the SOD and SDD groups, as compared with the standard-care group, were 0.86 (95% confidence interval [CI], 0.74 to 0.99) and 0.83 (95% CI, 0.72 to 0.97), respectively. CONCLUSIONS: In an ICU population in which the mortality rate associated with standard care was 27.5% at day 28, the rate was reduced by an estimated 3.5 percentage points with SDD and by 2.9 percentage points with SOD. (Controlled Clinical Trials number, ISRCTN35176830.)

Treatment of presumed acute cardiogenic pulmonary oedema in an ambulance system by nurses using Boussignac continuous positive airway pressure.

BACKGROUND: Early initiation of continuous positive airway pressure (CPAP) applied by face mask benefits patients with acute cardiogenic pulmonary oedema (ACPE). The simple disposable Boussignac CPAP (BCPAP) has been used in ambulances by physicians. In the Netherlands, ambulances are manned by nurses and not physicians. It was hypothesised that ambulance nurses are able to identify patients with ACPE and can successfully apply BCPAP. A prospective case series of patients with presumed ACPE treated with BCPAP by ambulance nurses is described. METHODS: After training of ambulance nurses, all 33 ambulances in the region were equipped with BCPAP. ACPE was diagnosed on clinical signs and pulse oximetry saturation (Spo(2)) <95%. BCPAP (5 cm H(2)O, Fio(2)>80%) was generated with an oxygen flow of 15 l/min. The physiological responses, experiences and clinical outcomes of the patients were collected from ambulance and hospital records, and ambulance nurses and patients received a questionnaire. RESULTS: From March to December 2006, 32 patients (age range 61-94 years) received BCPAP during transport to six different regional hospitals. In 26 patients (81%) a diagnosis of ACPE was confirmed. With BCPAP, median (IQR) Spo(2) increased from 79% (69-94%) to 96% (89-98%) within 20 min. The median (IQR) duration of BCPAP treatment was 26 min (21-32). The patients had no negative recollections of the treatment. Ambulance personnel were satisfied with the BCPAP therapy. CONCLUSION: When applied by ambulance nurses, BCPAP was feasible and effective in improving oxygen saturation in patients with ACPE. Although survival benefit can only be demonstrated by further research, it is considered that BCPAP can be implemented in all ambulances in the Netherlands.

[Less ventilator-associated pneumonia after oral decontamination with chlorhexidine; a randomised trial]. / Minder beademingspneumonieën door orale decontaminatie met chloorhexidine; gerandomiseerde trial.

OBJECTIVE: To determine the effect of oral decontamination with either chlorhexidine (CHX, 2%) or the combination chlorhexidine-colistin (CHX-COL, 2%-2%) on the frequency and the time to onset of ventilator-associated pneumonia in Intensive Care patients. DESIGN: Double blind, placebo-controlled, multicentre, randomised trial. METHODS: Consecutive ICU patients needing at least 48 h of mechanical ventilation were enrolled in a randomized trial with 3 arms: CHX, CHX-COL, and placebo (PLAC). The trial medication was administered in the oral cavity every 6 h. Oropharyngeal swabs were obtained daily and analysed quantitatively for Gram-positive and Gram-negative microorganisms. Endotracheal colonisation was monitored twice weekly. Ventilator-associated pneumonia was diagnosed on the basis of a combination of clinical, radiological and microbiological criteria. RESULTS: Of 385 patients included, 130 received PLAC, 127 CHX and 128 CHX-COL. Baseline characteristics in the three groups were comparable. The daily risk of ventilator-associated pneumonia was reduced in both treatment groups compared to PLAC: 65% (HR= 0.352; 95% CI: 0.160-0.791; p = 0.012) for CHX and 55% (HR= 0.454; 95%/ CI: 0.224-0.925; p = 0.030) for CHX-COL. CHX-COL provided a significant reduction in oropharyngeal colonisation with both Gram-negative and Gram-positive microorganisms, whereas CHX significantly affected only colonisation with Gram-positive microorganisms. There were no differences in the duration of mechanical ventilation, ICU-stay or ICU-survival. CONCLUSION: Oral decontamination of the oropharyngeal cavity with chlorhexidine or the combination chlorhexidine-colistin reduced the incidence and the time to onset ofventilator-associated pneumonia.

Disease severity is a major determinant for the pharmacodynamics of propofol in critically ill patients.

As oversedation is still common and significant variability between and within critically ill patients makes empiric dosing difficult, the population pharmacokinetics and pharmacodynamics of propofol upon long-term use are characterized, particularly focused on the varying disease state as determinant of the effect. Twenty-six critically ill patients were evaluated during 0.7-9.5 days (median 1.9 days) using the Ramsay scale and the bispectral index as pharmacodynamic end points. NONMEM V was applied for population pharmacokinetic and pharmacodynamic modeling. Propofol pharmacokinetics was described by a two-compartment model, in which cardiac patients had a 38% lower clearance. Severity of illness, expressed as a Sequential Organ Failure Assessment (SOFA) score, particularly influenced the pharmacodynamics and to a minor degree the pharmacokinetics. Deeper levels of sedation were found with an increasing SOFA score. With severe illness, critically ill patients will need downward titration of propofol. In patients with cardiac failure, the propofol dosages should be reduced by 38%.

Significant reduction in blood loss in patients undergoing minimal extracorporeal circulation.

Several recent studies have shown differences in blood loss and allogeneic transfusion requirements between on-pump and off-pump coronary artery bypass grafting (CABG). Recently a new concept, the mini-extracorporeal circulation, was introduced to minimize the side effects of extracorporeal circulation. Therefore, there are no data comparing the three techniques with special emphasis to blood loss and transfusion requirements. Two hundred and eighty-five patients undergoing first-time coronary artery bypass grafting were retrospectively matched for number of grafts, age and sex. Ninety-five patients underwent surgery with the off-pump CABG (OPCAB) technique, 97 patients using conventional CABG with cold cardioplegia (CCABG) and 93 patients with the mini-extracorporeal circuit with warm blood cardioplegia (MCABG). Blood loss for the CCABG group with a mean loss of 819 +/- 557 mL and the OPCAB group with a mean loss of 870 +/- 768 mL was significant different compared to the MCABG group with a mean loss of 679 +/- 290 mL. The use of units red blood cell units was significantly higher for CCABG group and OPCAB group compared to the MCABG group. On the day of operation the use of platelet concentrate was significantly higher for the CCABG group compared to MCABG group. As a consequence of improvements of several components of the mini heart lung machine, significantly less blood products are needed in MCABG patients. The expected reduced need for transfusion when the pump was completely avoided could not be confirmed in this single retrospective cohort study.

Clinical prospective study of biochemical markers and evoked potentials for identifying adverse neurological outcome after thoracic and thoracoabdominal aortic aneurysm surgery.

BACKGROUND: Neurological deficit after repair of a thoracic or thoracoabdominal aortic aneurysm (TAA/TAAA) remains a devastating complication. The aim of our study was to investigate the clinical value of biochemical markers [S-100B, neurone-specific enolase (NSE) and lactate dehydrogenase (LD)], evoked potentials and their combinations for identifying adverse neurological outcome after TAA/TAAA surgery. METHODS: From 69 patients, cerebrospinal fluid and blood samples for biochemical analysis were drawn after the induction of anaesthesia, during the cross-clamp period, 5 min, 2, 4, 6, 8, and 19 h, respectively, after reperfusion. In addition, continuous perioperative recording of motor-evoked potentials after transcranial electrical stimulation (tcMEP) and somatosensory-evoked potentials was carried out. Furthermore, neurological examinations were performed. RESULTS: In patients with a defined decrease in lower extremity tcMEP during the cross-clamp period, we found that combinations of the serum concentrations of S-100B and tcMEP ratios at 4, 6, and 8 h after reperfusion had a positive and negative predictive value of 100% in predicting adverse neurological outcome after TAA/TAAA surgery. Furthermore, combinations of the serum concentrations of S-100B and NSE or LD at 19 h after reperfusion had both a positive and negative predictive value of 100% in identifying patients with adverse outcome after TAA/TAAA repair. CONCLUSIONS: TcMEP monitoring during TAA/TAAA surgery seems to be an effective but not completely sufficient guide in our protective multi-modality strategy. Combinations of the serum concentrations of S-100B and tcMEP ratios during the early reperfusion period might be associated with adverse neurological complications. Furthermore, biochemical markers could detect central nervous system injury on the first postoperative day and may have prognostic value.

[The significance of elevated troponin levels in the absence of acute cardiac ischaemia]. / De betekenis van een verhoogde troponinewaarde zonder acute ischemische hartziekte.

Cardiac troponin I (cTnI) and cardiac troponin T (cTnT) are valuable heart markers in patients presenting with symptoms of ischaemic heart disease. A number of categories of patients frequently have raised concentrations of cardiac troponin (cTn) without having ischaemic heart disease. These include patients with heart diseases such as heart failure, myocarditis and valvular disease but also those with lung emboli, renal failure and sepsis. Possible underlying mechanisms are diffuse necrosis, cTn proteolysis or leakage of cytoplasmatic cTn with no irreversible damage to the contraction complex of heart-muscle cells. It is possible that cTn-measurement in patients with non-cardiac conditions is of prognostic value but so far this has only been demonstrated in dialysis patients and patients with pulmonary embolism.

Pneumoproteins as a lung-specific biomarker of alveolar permeability in conventional on-pump coronary artery bypass graft surgery vs mini-extracorporeal circuit: a pilot study.

BACKGROUND: Despite improvements of the heart-lung machine (HLM), oxidative stress and subsequent damage to the alveolar capillary membrane still occur after conventional on-pump coronary artery bypass graft (CCABG) surgery. In an attempt to further improve the conventional HLM, a mini-extracorporeal circuit (MECC) was introduced. This new concept is based on minimal volume shifts. The extent of alveolar injury that is associated with this new technique is unknown. The lung-specific biomarkers Clara-cell 16 (CC16) and KL-6 are applied in this study to quantify alveolar dysfunction in both techniques. METHODS: In a prospective observational setting, the concentrations of CC16 and KL-6 were measured during and after 10 consecutive CCABG operations and 10 consecutive coronary artery bypass graft (CABG) operations using MECC (MCABGs). These pneumoproteins were measured after the induction of anesthesia, before clamping of the ascending aorta, after unclamping of the aorta, on arrival to the ICU, and on the following days until discharge. Quantification of the differences of KL-6 and CC16 leakage through the alveolar membranes between the two techniques was realized by calculation of the Student t test. Perioperative and postoperative shunt fractions and clinical observations were monitored simultaneously. The potential value of pneumoproteins as biomarkers for quantification of alveolar permeability during CABG surgery was tested. RESULTS: Significantly reduced concentrations of CC16 were found early after MCABG as compared to CCABG surgery (p = 0.033). KL-6 showed no consistent pattern during both treatment modalities. Early after CCABG surgery, shunt fractions tended to show reduced oxygen transport over the alveolar membrane as compared to MCABG surgery. CONCLUSION: CC16 appears to be a useful biomarker for alveolar permeability during CABG surgery. Injury of the alveolar capillary membrane appears significantly reduced during MCABG surgery. Consistently early postoperative alveolar shunt fractions showed an increased value in CCABG compared to MCABG surgery in the early postoperative phase. Further randomized studies need to confirm the value of CC16 as marker in monitoring alveolar capillary damage during coronary bypass grafting.