Effects of repeated CPR training in virtual worlds on medical students' performance.

We report on a study that investigates the relationship between repeated training of teams managing a medical emergency (CPR) in a Virtual World and performance outcome measures in a group of 12 medical students. The focus of the training was on individual actions, but also on interaction and behavior in the team. Current CPR training seems to lack important team training aspects which this type of training is addressing. Although a pilot study, we found clear indications of improved performance related to reduced number of errors and an increased CPR efficiency. This type of educational technology could be expanded to other groups for a similar purpose because of its easiness to use, adaptability and interactivity.

Implementing virtual worlds for systematic training of prehospital CPR in medical school.

We report on a study that investigates the relationship between repeated training of teams managing medical emergencies in the Virtual World and affective learning outcomes in a group of 12 medical students. The focus of the training was on individual actions, but also on interaction and behaviour in the team. Current CPR training seems to lack important team training aspects which this type of training is addressing. We found an increase in flow experience and in self efficacy. This type of training could probably be expanded to other groups for a similar purpose because of its easiness to use, adaptability and interactivity.

Quantitative estimation of errors in the indicator dilution measurement of extravascular lung water.

OBJECTIVE: To assess the accuracy of the diffusible indicators heavy water and thermal indicator in the measurement of extravascular lung water (EVLW). DESIGN: Cardiac output (CO), mean transit time and EVLW for the two diffusible indicators were measured. CO for indocyanine green, gravimetric EVLW and the calculated mean transit time for a diffusible indicator were used as independent reference variables. CO, mean transit time and EVLW for the two diffusible indicators were compared to the reference variables and the percentage error for each measured variable was calculated for each bolus injection. SETTING: 6 sheep with healthy lungs and 6 with pulmonary oedema in a research laboratory. INTERVENTIONS: CO was altered with positive end-expiratory pressure and dobutamine. MEASUREMENTS: All indicators were given together in a bolus through a central venous line. Indicators were detected simultaneously in the aorta, and CO, mean transit time and EVLW were measured. EVLW was measured gravimetrically (EVLWgrav) postmortem. RESULTS: In the combination of a low CO and a large distribution volume, heavy water and thermal indicator produced a large number of slow wash-out curves. These curves were abolished from further analysis. The mean errors in CO and mean transit time for heavy water were close to zero and independent of the distribution volume; the product EVLW was close to EVLWgrav. The mean error in thermodilution CO measured in the aorta was close to zero but dependent on the distribution volume. The mean error in mean transit time for the thermal indicator was 36% and dependent on the distribution volume. Their product EVLW overestimated EVLWgrav by 70%. CONCLUSIONS: The results obtained for heavy water confirmed the theoretical basis of the indicator dilution method. The mean transit time for the thermal indicator was not proportionate to its distribution volume. The magnitude of this error prevents the calculation of an anatomically defined EVLW using a catheter-mounted thermistor in the aorta.

Estimation of extravascular lung water in humans with use of 2H2O: effect of blood flow and central blood volume.

In the present human study we evaluated a newly developed double-indicator-dilution densitometric system for the estimation of cardiac output (Q), central blood volume (CBV), and extravascular lung water (EVLW) by using indocyanine green and heavy water (2H2O) as indicators. Eighteen cardiopulmonary healthy patients scheduled for abdominal surgery were studied. A routine anesthesia procedure was used [thiopental (3-5 mg/kg), N2O (inspired fraction of O2 = 0.4), and isoflurane (end tidal 0.5-1.5%)]. Q, CBV, and EVLW were measured at seven defined data collection points: awake, anesthetized spontaneously breathing, apneic, mechanically ventilated with and without positive end-expiratory pressure, post-operatively anesthetized, and postoperatively awake. During the whole study EVLW (3.8 +/- 0.9 ml/kg) was stable in the presence of large fluctuations in Q (2.5-10.1 l/min) and CBV (0.8-2.4 l). We concluded that the method is versatile and of low invasiveness, allowing reliable on-line Q and EVLW data for repeated measurements in the clinical setting.

Training trauma teams in the Nordic countries: an overview and present status.

BACKGROUND: During the last decade there has been an increased interest in the organisation and quality of trauma care in the Nordic countries. Still, most patients are initially cared for at hospitals with low caseloads of severe trauma. More than 200 hospitals offer initial care to trauma patients. Training of trauma teams using simulators or simulated patients has evolved in the same period, as one important factor to overcome lack of practical training. This overview describes the present state of trauma team training in the Nordic countries. METHODS: Members of a Nordic working group on the use of simulation in medicine reviewed present literature on training with simulation and described the present use of team training in their own countries during winter 2004. RESULTS: There is an increasing amount of evidence indicating that training of teams with simulation reduces treatment errors and improves performance. The training activities do not need to be complex, but skilled debriefing seems necessary. Few Nordic hospitals train their trauma teams. The training activities vary considerably between and within countries. CONCLUSION: There is considerable evidence supporting an increased use of experience gained in other high-risk domains where training in communication, leadership and decision-making is the focus for safety and improvement efforts. There is a need for more widespread training of trauma teams. The different training activities actually undertaken should be scientifically evaluated.

Massive metoprolol poisoning treated with prenalterol.

A case of massive metoprolol poisoning (50 g) is described. Clinical signs included coma, seizures, hypoventilation, unmeasurable blood pressure, nodal bradycardia, and metabolic acidosis. Treatment comprised intubation, assisted ventilation, gastric lavage, atropine, bicarbonate, glucagon and repeated doses of prenalterol (a total of 160 mg over 15 hours). Prenalterol dosage was simple and could be guided by blood pressure response. Pacemaker treatment was not required. Ethanol concentration was 50 mmol/l (2.4%) on admission. Plasma metoprolol was 68 mumol/l (18 000 ng/ml) 2 hours after admission. The patient was awake after 15 hours.

Subclinical pulmonary oedema and intermittent haemodialysis.

It has been postulated that patients with chronic renal failure, even in the absence of cardiopulmonary symptoms, accumulate interstitial pulmonary fluid, which is removed by haemodialysis. To test this hypothesis we used the indocyanine green (ICG)-heavy water double indicator dilution method to measure lung water, cardiac output, and central blood volume in relation to haemodialysis. Ten uraemic patients, without cardiopulmonary symptoms, were investigated at the beginning and end, and 2 h after, a regular dialysis session. A group of 18 surgical patients about to undergo elective abdominal surgery served as controls. Despite normal gas exchange, central blood volume, and cardiac output at the start of dialysis the mean (SD) lung water was significantly higher than in the control group [4.8 (0.9) compared with 3.6 (0.7) ml/kg, P < 0.001]. There was no correlation between weight gain between sessions of dialysis and the magnitude of lung water at the start of dialysis. Lung water decreased (P < 0.001) to the level of the control group in response to dialysis. There was no correlation between weight loss and reduction in lung water induced by dialysis. In conclusion, we have verified the presence of subclinical pulmonary oedema which was removed by dialysis in a group of patients with established renal failure. The variations in lung water cannot be explained by hydrostatic mechanisms alone.

Water diuretic effect of intravenously administered 9-deoxo-16, 16-dimethyl-9-methylene-PGE2 in conscious man.

The stable prostaglandin analogue 9-deoxo-16, 16-dimethyl-9-methylene-PGE2 (9-methylene-PGE2) was infused intravenously (0.5 ml/min) in the dosage of 20 micrograms/min for 2 h in conscious euhydrated man. The administration of 9-methylene-PGE2 rapidly induced an increase in urine flow (from 1.2 +/- 0.07 to 5.35 +/- 1.07 ml/min) concomitantly with a decrease in urine osmolality (from 827 +/- 40 to 193 +/- 44 mOsm/kg). Parallel to this tubular reabsorption of sodium (Na+), calcium (Ca2+) and magnesium (Mg3+) increased and that of potassium (K+) decreased as shown by a reduction in the clearance for respective ion divided by the clearance of inulin. Apparently the water diuresis was mediated by an inhibition of arginine vasopressin's (AVP) antidiuretic effect. The mechanism behind the increase in renal tubular reabsorbtion of Na+ could possibly be a 9-methylene-PGE2 mediated modulation of the renal aldosterone effect. However the protocol followed did not provide any evidence for this, or any other explanation of the observed renal retention of Na+, Ca2+ and Mg2+. The results reported here indicate that 9-methylene-PGE2 may have a future use as a water diuretic agent in patients suffering from water retention and dilutional hyponatraemia such as seen in the syndrome of inappropriate antidiuretic hormone (AVP) release commonly known as SIADH or Schwartz-Bartter's Syndrome.

Effects of rapid colloid volume expansion on pulmonary microvascular pressure and lung water in the conscious sheep.

Increased pulmonary microvascular pressure (Pmv), in combination with other factors, may cause pulmonary interstitial oedema. Whether increased Pmv alone induces alveolar oedema is questionable. In the present study we used the heavy water-indocyanine green dilution method to measure lung water during a rapid intravascular volume expansion in the sheep. Eight conscious sheep were given two 10-min intravenous infusions of either 50 ml/kg (N = 2) or 35 ml/kg (N = 6) of dextran 60 with an interval of 10 min between them. At a Pmv of 40 mmHg, respiratory distress was observed in sheep no. 2 which had been given a total amount of 100 ml/kg of dextran; this was immediately followed by a lethal pulmonary haemorrhage. Mean Pmv in the remaining seven sheep increased to 31 (7) mmHg in response to the volume expansion without causing any respiratory distress or increase in lung water. These results show that in conscious sheep the lungs have strong protective mechanisms against hydrostatic oedema. They do not support the hypothesis that increased Pmv alone induces alveolar oedema, but suggest that an increase in Pmv to 40 mmHg may cause stress failure of the pulmonary vasculature.

Pneumoperitoneum in healthy humans does not affect central blood volume or cardiac output.

BACKGROUND: This study addresses the question of whether the elevation of the mean arterial pressure and central venous pressure in response to pneumoperitoneum for laparoscopic surgery is caused by increases in central blood volume and/or cardiac output. METHODS: Eleven patients in good cardiopulmonary health and scheduled for laparoscopic cholecystectomy, with a mean age of 42 years, were included. After induction of anaesthesia with fentanyl and propofol, radial arterial and central venous lines were introduced. The central blood volume and cardiac output were determined by the indicator-dilution technique, using inline densitometric measurements of indocyanine green (ICG). The measurements were made before and after the establishment of pneumoperitoneum by insufflation of carbon dioxide to an intra-abdominal pressure level of 11-13 mmHg. RESULTS: The mean arterial pressure (62+/-6 mmHg) increased after induction of pneumoperitoneum by 40+/-26% (P<0.05) and the central venous pressure increased from 6+/-4 mmHg to 8+/-6 mmHg (P<0.05). The cardiac output (4.3+/-0.9 L/min) and central blood volume (1.5+/-0.5 L) were not affected by the induction of pneumoperitoneum. CONCLUSIONS: In healthy anaesthetized subjects, the elevation of mean arterial pressure and central venous pressure in response to pneumoperitoneum was not caused by enhancement in cardiac output or central blood volume.

The prostaglandin-analogue-9-deoxo-16,16-dimethyl-9-methylene-PGE2 inhibits the antidiuretic effect of vasopressin (AVP) in the conscious sheep.

The effects of intravenous infusions of the stable prostaglandin analogue 9-deoxo-16,16-dimethyl-9-methylene-PGE2 (9-methylene-PGE2) in a dosage of 10 or 24 micrograms/min were studied in the consicious euhydrated, dehydrated, and hyperhydrated with the simultaneous administration of exogenous arginine vasopressin (AVP), sheep. The infusions decreased urine osmolality and increased urine flow and renal free water clearance. The results indicate that 9-methylene-PGE2 exhibits its diuretic effect by antagonizing the antidiuretic action of AVP. In the hyperhydrated sheep receiving AVP the syndrome of inappropriate antidiuretic hormone release (SIADH) was simulated. As the prostaglandin analogue effectively blocked the antidiuretic effect of the AVP-administration it appears that 9-methylene-PGE2 may play a future role as a diuretic agent, especially in conditions characterized by water retention and dilutional hyponatremia such as SIADH.