End-of-life perceptions among physicians in intensive care units managed by anesthesiologists in Germany: a survey about structure, current implementation and deficits.

BACKGROUND: Structural aspects and current practice about end-of-life (EOL) decisions in German intensive care units (ICUs) managed by anesthesiologists are unknown. A survey among intensive care anesthesiologists has been conducted to explore current practice, barriers and opinions on EOL decisions in ICU. METHODS: In November 2015, all members of the German Society of Anesthesiology and Intensive Care Medicine (DGAI) and the Association of German Anesthesiologists (BDA) were asked to participate in an online survey to rate the presence or absence and the importance of 50 items. Answers were grouped into three categories considering implementation and relevance: Category 1 reflects high implementation and high relevance, Category 2 low and low, and Category 3 low and high. RESULTS: Five-hundred and forty-one anesthesiologists responded. Only four items reached ≥90% agreement as being performed "yes, always" or "mostly", and 29 items were rated "very" or "more important". A profound discrepancy between current practice and attributed importance was revealed. Twenty-eight items attributed to Category 1, six to Category 2 and sixteen to Category 3. Items characterizing the most urgent need for improvement (Category 3) referred to patient outcome data, preparation of health care directives and interdisciplinary discussion, standard operating procedures, implementation of practical instructions and inclusion of nursing staff and families in the process. CONCLUSION: The present survey affirms an urgent need for improvement in EOL practice in German ICUs focusing on advanced care planning, distinct aspects of changing goals of care, implementation of standard operating procedures, continuing education and reporting of outcome data.

Detection and distribution of opioid peptide receptors in porcine myocardial tissue.

There is growing evidence that opioid peptide receptors (OPRs) play an important role in cardiovascular function. Many studies have been conducted in swine, in view of their anatomic and physiologic similarities to humans. Until now, the presence and particularly distribution of OPRs has been unclear. Porcine myocardial tissue was obtained from both the left and right atria and ventricles. Expression of mRNA for µ-, δ- and κ-OPR was determined by reverse transcription PCR. OPR proteins were detected by Western blot, distribution and cellular location were identified using immunohistochemistry. Homogenous expression of mRNA and protein for δ- and κ-OPRs were demonstrated in all porcine myocardial tissue tested, whereas expression of µ-OPR mRNA was not demonstrated in any of the tissues tested. This study demonstrates the expression of δ- and κ-OPRs in porcine myocardial tissue. No differences in distribution of δ- and κ-OPRs were found between the four heart cavities. Modulation of cardiac function by δ- and κ-OPR agonists or antagonists is therefore possible, while µ-OPR-mediated direct cardiac effects appear unlikely, due to nonexpression of the receptor. This study demonstrates that porcine studies can further elucidate the role of OPRs in cardiac (patho-)physiology.

Sleep disturbances after posterior scoliosis surgery with an intraoperative wake-up test using remifentanil.

BACKGROUND: The intraoperative wake-up test is a standard procedure for early recognition of neurologic complications after posterior correction of idiopathic scoliosis. In this prospective, single-blinded cohort study, the impact of the wake-up test and the opioid used for anesthesia on the quality of the patients' sleep after scoliosis surgery was investigated up to 12 months postoperatively. METHODS: Patients were classified into three groups: posterior instrumentation with wake-up test using remifentanil, anterior instrumentation without wake-up test using sufentanil, and posterior instrumentation with wake-up test using sufentanil. The quality of sleep was assessed using the Pittsburgh Sleep Quality Index questionnaire preoperatively as well as 3, 6, and 12 months postoperatively. In addition, data were collected on patients' age, weight, and sex, as well as the duration of the operation and anesthesia, amount of blood loss, specific opioid dosages, and wake-up test times. Statistical analysis was conducted using the Mann-Whitney, Kruskal-Wallis, and Wilcoxon tests. RESULTS: There were no differences between groups with regard to baseline characteristics. No explicit recall was assessed through all groups. At 3 and 6 months postoperatively, the sleep quality in the posterior-remifentanil group was significantly poorer than preoperatively and compared with the anterior- and posterior-sufentanil groups. No significant differences in wake-up test times between groups undergoing posterior instrumentation occurred. CONCLUSIONS: This study suggests that patients undergoing scoliosis surgery with an intraoperative wake-up test using remifentanil had impaired sleep quality that lasted up to 6 months postoperatively. No deterioration in sleep quality was observed with sufentanil. Large randomized trials are now needed to confirm these preliminary results.

Dual-lumen catheters for continuous venovenous hemofiltration: limits for blood delivery via femoral vein access and a potential alternative in an experimental setting in anesthetized pigs.

INTRODUCTION: Small intravascular volume, pathophysiological hemorheology, and/or low cardiac output [CO] are assumed to reduce available blood flow rates via common dual-lumen catheters (except for those with a right atrium catheter tip position) in the critically ill patient. We performed an experimental animal study to verify these assumptions. METHODS: Anesthetized, ventilated pigs (35 to 50 kg) were allocated to different hemorheological conditions based on the application of different volume substitutes (that is, colloids and crystalloids, n = 6 to 7 per volume substitute). In a second step, allocation to the final study group was performed after the determination of the highest values for access flow (Qa) via an axial dual-lumen catheter (11 French, 20 cm long, side holes) placed in the femoral vein. High Qa rates (>300 ml/minute) were allocated to the dual-lumen catheter group; low Qa rates were switched to a 'dual-vein approach' using an alternative catheter (8.5-French sheath) for separate blood delivery. Hemodynamics (CO and central venous pressure [CVP]) and blood composition (blood cell counts, plasma proteins, and colloid osmotic pressure) were measured. Catheter tip positions and vessel diameters were exemplified by computed tomography. RESULTS: Forty-four percent of the animals required an alternative vascular access due to only minimal Qa via the dual-lumen catheter. Neither hemorheologically relevant aspects nor CO and CVP correlated with the Qa achievable via the femoral vein access. Even though the catheter tip of the alternative catheter provided common iliac vein but not caval vein access, this catheter type enabled higher Qa than the dual-lumen catheter positioned in the caval vein. CONCLUSION: With respect to the femoral vein approach, none of the commonly assumed reasons for limited Qa via the arterial line of an axial dual-lumen catheter could be confirmed. The 8.5-French sheath, though not engineered for that purpose, performed quite well as an alternative catheter. Thus, in patients lacking right jugular vein access with tip positioning of large-French dual-lumen catheters in the right atrium, it would be of interest to obtain clinical data re-evaluating the 'dual-vein approach' with separate blood delivery via a tip-hole catheter in order to provide high-volume hemofiltration.

Kappa-opioid receptor antagonism improves recovery from myocardial stunning in chronically instrumented dogs.

We tested the hypothesis that the selective kappa-opioid receptor antagonist nor-binaltorphimine (nor-BNI) improves recovery from myocardial stunning. Ten dogs were chronically instrumented for measurement of heart rate, left atrial, aortic and left ventricular pressure (LVP), and the maximum rate of LVP increase (LV dP/dt(max)) and decrease (LV dP/dt(max)), coronary blood flow velocity and myocardial wall-thickening fraction. Regional myocardial blood flow was determined with fluorescent microspheres. Catecholamine plasma levels were measured by high-performance liquid chromatography, and beta-endorphin and dynorphin plasma levels by radioimmunoassay. An occluder around the left anterior descending artery (LAD) allowed induction of a reversible LAD-ischemia. Animals underwent two experiments in a randomized crossover fashion on separate days: (a) 10 min LAD-occlusion (control experiment), (b) second ischemic episode 24 h after nor-BNI (2.5 mg/kg IV) (intervention). Dogs receiving nor-BNI showed an increase in wall-thickening fraction, LV dP/dt(max) and LV dP/dt(min) before ischemia and during the whole reperfusion (P < 0.05 versus control experiment). After nor-BNI pretreatment, dynorphin levels increased after induction of ischemia to a peak level of 15.1 +/- 3.6 pg/mL (P < 0.05 versus control experiment). The increase in plasma beta-endorphin during ischemia and early reperfusion was attenuated after nor-BNI. Compared with the control experiment, nor-BNI left global hemodynamics, regional myocardial blood flow, and catecholamine levels unchanged. In conclusion, nor-BNI improves recovery from myocardial stunning after regional myocardial ischemia in chronically instrumented dogs.

Plasma disappearance of indocyanine green: a marker for excretory liver function?

OBJECTIVE: To investigate whether the plasma disappearance rate of indocyanine green (ICG) assessed using a commercially available bedside monitor provides an accurate estimation of cumulative biliary ICG excretion in a clinically relevant model of long-term, hyperdynamic porcine endotoxemia. DESIGN AND SETTING: Prospective experimental study in the animal laboratory in a university hospital. SUBJECTS: Fifteen domestic pigs. INTERVENTIONS: Pigs were anesthetized, mechanically ventilated, and instrumented. Intravenous endotoxin was continuously infused over 12 h concomitant with fluid resuscitation. Measurements were performed before and 12 h after the start of endotoxin infusion. MEASUREMENTS AND RESULTS: All animals developed hyperdynamic circulation characterized by a sustained increase in cardiac output. Despite well maintained portal venous and consequently total liver blood flow endotoxemia decreased hepatic lactate uptake, which was accompanied by a significant fall in portal and hepatic venous pH. Both the cumulative bile flow and biliary ICG and bicarbonate excretion measured during 1 h after intravenous bolus of 25 mg ICG fell significantly. By contrast, neither the plasma disappearance rate of ICG nor the rate corrected for liver blood flow exhibited any changes over time. CONCLUSIONS: In hyperdynamic porcine endotoxemia the plasma disappearance rate of ICG failed to accurately substitute for direct short-term measures of biliary ICG excretion. Hence normal values of plasma disappearance rate of ICG should be interpreted with caution in early, acute inflammatory conditions.

Xenon improves recovery from myocardial stunning in chronically instrumented dogs.

In this study we tested the hypothesis that inhalational administration of xenon improves recovery from myocardial stunning. Ten dogs were chronically instrumented for measurement of heart rate; left atrial, aortic, and left ventricular pressure; coronary blood-flow velocity; and myocardial wall-thickening fraction. Regional myocardial blood flow was determined with fluorescent microspheres. Catecholamine plasma levels were measured by high-performance liquid chromatography. An occluder around the left anterior descending artery (LAD) allowed the induction of a reversible LAD ischemia. Animals underwent 2 experimental conditions in a randomized crossover fashion on separate days: (a) 10 min of LAD occlusion under fentanyl (25 microg. kg(-1). h(-1)) and midazolam (0.6 mg. kg(-1). h(-1)) (control) and (b) a second ischemic episode under the same basal anesthesia with concomitant inhalational administration of 75 +/- 1 vol% xenon (intervention). Anesthesia was induced 35 min before LAD occlusion and was discontinued after 20 min of reperfusion. Dogs receiving xenon showed a significantly better recovery of wall-thickening fraction up to 12 h after ischemia. The increase in plasma epinephrine during emergence from anesthesia and in the early reperfusion period was significantly attenuated in the xenon group. There were no differences between groups concerning global hemodynamics, blood-flow velocity, or regional myocardial blood flow. In conclusion, inhalational administration of 75 vol% xenon improves recovery from myocardial stunning in chronically instrumented dogs under fentanyl/midazolam anesthesia.

Adenosine triphosphate-magnesium dichloride during hyperdynamic porcine endotoxemia: effects on hepatosplanchnic oxygen exchange and metabolism.

OBJECTIVE: To assess the effects of adenosine triphosphate-magnesium dichloride (ATP-MgCl2) on systemic and hepatosplanchnic hemodynamics, oxygen exchange, and energy metabolism over 24 hrs of hyperdynamic normotensive porcine endotoxemia. DESIGN: Prospective, randomized, controlled experimental study with repeated measures. SETTING: Investigational animal laboratory. SUBJECTS: Seventeen pigs were divided into two groups: eight animals receiving endotoxin served as a control group and nine animals received endotoxin (lipopolysaccharide) and ATP-MgCl2. INTERVENTIONS: Pigs were anesthetized, mechanically ventilated, and instrumented. Endotoxemia was achieved by continuous intravenous infusion of Escherichia coli lipopolysaccharide. Animals were resuscitated by hetastarch targeted to maintain mean arterial pressure of >75 mm Hg. Twelve hours after the start of the endotoxin infusion, ATP-MgCl2, or its vehicle, were administered for 12 hrs. MEASUREMENTS AND MAIN RESULTS: Mean arterial pressure was maintained in the control group because of a sustained increase in cardiac output achieved by fluid resuscitation, whereas ATP-MgCl2 significantly decreased mean arterial pressure because of further systemic vasodilatation. ATP-MgCl2 markedly increased portal venous flow. In contrast to the controls, hepatic arterial flow remained unchanged until the end of the experiment, despite the further increase in cardiac output. The ileal mucosal-arterial PCO2 gap (Delta PCO2) progressively increased (p <.05) in control animals, whereas it was restored to prelipopolysaccharide levels during ATP-MgCl2 infusion. Changes in Delta PCO2 correlated with those of portal vein blood flow in these animals (r = -.68, p <.05). Moreover, ATP-MgCl2 blunted the lipopolysaccharide-induced decrease in hepatic lactate balance but did not affect portal venous pH, hepatosplanchnic oxygen exchange, splanchnic lactate/pyruvate ratios, isoprostane, NO2- + NO3-, cytokine concentrations, or tissue nucleotide content. CONCLUSION: During long-term hyperdynamic porcine endotoxemia, ATP-MgCl2 normalized the otherwise progressive rise of the ileal mucosal-arterial Delta PCO2. Furthermore, it allowed blunting of the continuous decrease in hepatic lactate clearance, thus preserving the metabolic coupling between lactate release from the intestine and lactate utilization by the liver.

Inhaling nitrous oxide or xenon does not influence bowel wall energy balance during porcine bowel obstruction.

UNLABELLED: Xenon (Xe) is less soluble than nitrous oxide (N(2)O) and hence may be more suitable during bowel obstruction. Therefore, we compared the intestinal mechanical and biochemical effects of these two gases with those of total IV anesthesia in a porcine model of small-bowel obstruction. Intestinal obstruction was induced in 33 anesthetized pigs, in 18 of which segmental ileal perfusion was reduced by partial arterial occlusion. Pigs received total IV anesthesia, Xe, or N(2)O (in 30% oxygen) for 4 h, and we determined the intraluminal pressure and volume, the arterial-ileal PCO(2) gap, and the lactate and pyruvate levels in the segmental mesenteric vein. Under both experimental conditions, Xe or N(2)O ventilation caused the volume to significantly increase with a concomitant significant increase in the intraluminal pressure during N(2)O ventilation. Regardless of the anesthesia technique, none of the biochemical variables was influenced in the animals with maintained ileal blood supply. In contrast, reducing the segmental perfusion induced pronounced alterations of all variables of bowel wall energy metabolism. The type of anesthesia, however, had no further statistically significant effect. Short-term inhalation of Xe or N(2)O seems to have no deleterious effects on the metabolic balance of the gut wall during intestinal obstruction. IMPLICATIONS: In anesthetized pigs, short-term inhalation of xenon or nitrous oxide over 4 h when compared with total IV anesthesia had no additional deleterious effects on the metabolic balance of the gut wall during intestinal obstruction, no matter whether the arterial blood flow was reduced or not.