Elisabeth Oschatz

Accuracy of oscillometric blood pressure measurement according to the relation between cuff size and upper-arm circumference in critically ill patients.

Objective: To evaluate the accuracy of oscillometric blood pressure measurement according to the relation between cuff size and upper‐arm circumference in critically ill patients. Design: Prospective data collection. Setting: Emergency department in a 2,000‐bed inner city hospital. Patients: Thirty‐eight patients categorized into three groups according to their upper‐arm circumference (group I: 18‐25 cm; group II: 25.1‐33 cm; and group III: 33.1‐47.5 cm) were enrolled in the study protocol. Interventions: In each patient, all three cuff sizes (Hewlett‐Packard Cuff 40401 B, C, and D) were used to perform an oscillometric blood pressure measurement at least within 3 mins until ten to 20 measurements for each cuff size were achieved. Invasive mean arterial blood pressure measurement was done by cannulation of the contralateral radial artery with direct transduction of the systemic arterial pressure waveform. The corresponding invasive blood pressure value was obtained at the end of each oscillometric measurement. Measurement and Main Results: Overall, 1,494 pairs of simultaneous oscillometric and invasive blood pressure measurements were collected in 38 patients (group I, n = 5; group II, n = 23; and group III, n = 10) over a total time of 72.3 hrs. Mean arterial blood pressure ranged from 35 to 165 mm Hg. The overall discrepancy between oscillometric and invasive blood pressure measurement was −6.7 ± 9.7 mm Hg (p < .0001), if the recommended cuff size according to the upper‐arm circumference was used (539 measurements). Of all the blood pressure measurements, 26.4% (n = 395) had a discrepancy of ≥10 mm Hg and 34.2% (n = 512) exhibited a discrepancy of ≥20 mm Hg. No differences between invasive and noninvasive blood pressure measurements were noted in patients either with or without inotropic support (−6.6 + 7.2 vs. −8.6 + 6.8 mm Hg; not significant). Conclusion: The oscillometric blood pressure measurement significantly underestimates arterial blood pressure and exhibits a high number of measurements out of the clinically acceptable range. The relation between cuff size and upper‐arm circumference contributes substantially to the inaccuracy of the oscillometric blood pressure measurement. Therefore, oscillometric blood pressure measurement does not achieve adequate accuracy in critically ill patients.

Effects of bystander first aid, defibrillation and advanced life support on neurologic outcome and hospital costs in patients after ventricular fibrillation cardiac arrest

Abstract. Objective: To evaluate the effects of basic life support, time to first defibrillation and emergency medical service arrival time on neurologic outcome and expenses for hospital care in patients after cardiac arrest. Setting: Large urban emergency medical services system and emergency department in a 2000-bed university hospital. Design: Outcome and cost benefit analysis of patients admitted to the hospital after witnessed, out-of-hospital, ventricular fibrillation cardiac arrest from October 1, 1991, until December 31, 1997. Patients: Out of 1054 patients with out-of-hospital cardiac arrest, 276 were eligible. Measurements and results: The effects of basic and advanced life support measures on neurologic outcome and hospital expenses were evaluated. In contrast to intubation (odds ratio 1.08; 95% CI: 0.51–2.31; p=0.84), basic life support (odds ratio 0.44; 95% CI: 0.24–0.77; p=0.004) and time to first defibrillation (odds ratio 1.08; 95% CI: 1.03–1.13; p=0.001) were significantly correlated with good neurologic outcome. Among the patients who did not receive basic life support, the average cost per patient with good neurologic outcome significantly increased with the delay of the first defibrillation (p<0.001). Conclusions: In contrast to intubation, bystander basic life support and time to first defibrillation were significantly associated with good neurologic outcome and resulted in fewer expenses spent on in-hospital efforts.

Simultaneous comparison of thoracic bioimpedance and arterial pulse waveform-derived cardiac output with thermodilution measurement.

Objective To compare the accuracy and reliability of thoracic electrical bioimpedance (TEB) and the arterial pulse waveform analysis with simultaneous measurement of thermodilution cardiac output (TD-CO) in critically ill patients. Design Prospective data collection. Setting Emergency department and critical care unit in a 2,000-bed inner-city hospital. Patients A total of 29 critically ill patients requiring invasive hemodynamic monitoring for clinical management were prospectively studied. Interventions Noninvasive cardiac output was simultaneously measured by a TEB device and by analysis of the arterial pulse waveform derived from the finger artery. Invasive cardiac output was determined by the thermodilution technique. Measurements and Main Results A total of 175 corresponding TD-CO and noninvasive hemodynamic measurements were collected in 30-min intervals. They revealed an overall bias of 0.34 L/min/m2 (95% confidence interval, 0.24–0.44 L/min/m2;p < .001) for the arterial pulse waveform analysis and of 0.61 L/min/m2 (95% confidence interval, 0.50–0.72 L/min/m2;p < .001) for the TEB. In 39.4% (n = 69) of all measurements, the discrepancy between arterial pulse waveform analysis and TD-CO was >0.50 L/min/m2. The discrepancies of the arterial pulse waveform analysis correlated positively with the magnitude of the cardiac index (r2 = 0.29;p < .001). In 56.6% (n = 99) of all measurements, the discrepancy between TEB and TD-CO was >0.50 L/min/m2. The magnitude of the discrepancies of the TEB was significantly correlated with age (r2 = 0.17;p = .02). Measurements were in phase in 93.2% of all arterial pulse waveform analysis and in 84.9% of all TEB readings (p < .001). Conclusions The arterial pulse waveform analysis exhibits a greater accuracy and reliability as compared with the TEB with regard to overall bias, number of inaccurate readings, and phase lags. The arterial pulse waveform analysis may be useful for the monitoring of hemodynamic changes. However, both methods fail to be a substitute for the TD-CO because of a substantial percentage of inaccurate readings.

Cardiopulmonary resuscitation performed by bystanders does not increase adverse effects as assessed by chest radiography.

Important adverse effects of bystander cardiopulmonary resuscitation (CPR) are well known. We describe the number of nonmedical professional CPR-related complications in patients surviving cardiac arrest, as assessed by chest radiograph. Within 2 yr, all consecutive patients admitted to the department of emergency medicine at a university hospital who had a witnessed, nontraumatic, normothermic cardiac arrest were studied. Radiologically evaluated adverse effects were compared with Mann-Whitney U-tests between patients who received bystander basic life support (Bystander group) and patients who did not receive bystander basic life support before advanced life support was started (ALS group). For assessment of bystander CPR-associated complications, chest radiographs were used. Of 224 patients, 173 were eligible. The median age was 58 yr (interquartile range, 51–71 yr), and 126 patients (73%) were men. The incidence of adverse effects associated with assisted-ventilation maneuvers and external chest compressions did not differ significantly between groups (severe gastric insufflation, 17% vs 18% between the Bystander group [n = 59] and the ALS group [n = 96], respectively; suspicion of aspiration, 22% vs 17%, respectively; soft tissue emphysema, 2% vs 1%, respectively; and serial rib fractures, 8% vs 8%, respectively). CPR administered by nonmedical personnel did not increase the number of life support-related adverse effects in patients surviving cardiac arrest as assessed by means of chest radiograph on admission.

The influence of chest compressions and external defibrillation on the release of creatine kinase-MB and cardiac troponin T in patients resuscitated from out-of-hospital cardiac arrest

OBJECTIVES This study sought to determine the influence of resuscitative procedures, such as chest compressions and external defibrillation, on the release of creatine kinase (CK)-MB and cardiac troponin T (cTnT). METHODS In 87 patients with out-of-hospital cardiac arrest and successful cardiopulmonary resuscitation (CPR), the initial ECG rhythm, the duration of cardiac arrest and CPR, and the number of defibrillations were assessed on arrival in the hospital. The serum CK-MB and cTnT were measured 12 h after the event. We also assessed whether the patient developed cardiogenic shock within 12 h, and if the patient had acute myocardial infarction (AMI), which was confirmed or eliminated by of typical ECG findings, thallium-201 myocardial scintigraphy, or autopsy within the hospital stay. A backward stepwise linear regression model was applied to assess the association between the markers of myocardial injury (CK-MB and cTnT) and the above clinical variables. RESULTS CK-MB concentrations were independently associated with the presence of AMI [B 68.5 (SE 28.5, P = 0.018)], the duration of CPR (as a measure of trauma to the chest by means of chest compressions) [B 2.07 (SE 1.01, P = 0.045)] and cardiogenic shock [B 52.3 (SE 23.4, P = 0.03)]. The remaining clinical variables listed were excluded by the model. Cardiac troponin T concentrations were only associated with the presence of AMI [B 4.86 (SE 1.34, P = 0.0005)]. There was a non-significant association between increasing serum cTnT concentrations and the presence of cardiogenic shock [B 2.51 (SE 1.46, P = 0.09)]. The remaining clinical variables were excluded by the model. CONCLUSION The release of CK-MB appears to be influenced by the duration of resuscitation and the presence of cardiogenic shock. This has to be considered when interpreting serum CK-MB concentrations after CPR. The release of cTnT seems to be only associated with acute myocardial infarction, but not with the duration of chest compressions, or with the number of defibrillations administered.

Management of Patients with Small Pulmonary Nodules: A Survey of Radiologists, Pulmonologists, and Thoracic Surgeons

OBJECTIVE The objective of our study was to survey recommendations for the management of small pulmonary nodules found on helical CT from radiologists, pulmonologists, and thoracic surgeons. MATERIALS AND METHODS We surveyed 774 radiologists, 623 pulmonologists, and 101 thoracic surgeons. All are members of an associated Austrian scientific society and were asked for their recommendations in 13 hypothetical cases. Statistical analysis was focused on possible differences between medical specialities, residents and fellows, and male and female doctors and on a possible influence of the number of years in training or in medical practice. RESULTS Complete surveys were returned from 91 radiologists, 74 pulmonologists, and 12 thoracic surgeons. The most frequent recommendation from radiologists was follow-up, whereas the most frequent recommendation from pulmonologists and surgeons was biopsy. The most frequently advised CT follow-up period was 3 months. Whereas thoracic surgeons preferred video-assisted thoracoscopy, radiologists and pulmonologists recommended less invasive procedures (bronchoscopy, CT-guided biopsy) to gain a specific diagnosis. CONCLUSION There are significant differences in the management of small pulmonary nodules among radiologists, pulmonologists, and thoracic surgeons. Whereas radiologists tend to recommend short-term follow-up, pulmonologists and thoracic surgeons prefer a more aggressive approach, especially in patients with a higher likelihood of malignancy.

Comparison of liquid crystal versus cathode ray tube display for the detection of simulated chest lesions

The purpose of the study was to compare the detection performance of a cathode ray tube (CRT) monitor versus a liquid crystal display (LCD) monitor for simulated subtle pulmonary lesions. Ten templates containing simulated lung lesions were superimposed on an anthropomorphic chest phantom. Posteroanterior radiographs were obtained using flat panel technology and were displayed on a CRT and an LCD monitor. Image processing and reading conditions were equivalent for both softcopy displays. Five observers assessed lesion detectability using receiver-operating characteristic (ROC) methodology. A multivariate test (Pillai trace) was used to test the significance of differences (P<0.05). The multivariate test revealed significantly different detection rates for the lesion types, but no significant difference between the two display modes. Detection performance for both monitors was higher for nodules and micro-nodules and lower for lines and patchy opacities. Analysis of lesion subgroups according to their location in lucent/obscured lung areas was also not statistically significant. Under ideal reading conditions, CRT and LCD displays perform equivalently for the detection of simulated subtle pulmonary lesions.

Endothelin-1 elevates regional cerebral perfusion during prolonged ventricular fibrillation cardiac arrest in pigs

Since adrenaline (epinephrine) also has negative effects during and after cardiopulmonary resuscitation (CPR) a non-adrenergic vasoconstrictor like endothelin might be an alternative to increase vital organ blood flow. We studied the effect of different doses of endothelin-1 compared with adrenaline on the ability to resuscitate, cerebral and myocardial blood flow (MBF) in a closed chest cardiac arrest pig model. After 5 min of ventricular fibrillation, CPR with a ventilator and a mechanical compression device was started. At 10 min, 31 pigs were randomized to receive a single dose of endothelin-1 50, 100 or 200 microg or repeated doses of adrenaline 0.04 mg kg(-1) or saline every 3 min. After 25 min, the pigs were defibrillated to achieve restoration of spontaneous circulation. Blood flow was measured with the fluorescent microsphere method. In animals receiving endothelin-1 50, 100 and 200 microg the cerebral blood flow (CBF) increased from median 28 (25th; 75th quartile: 16; 40), 32 (15; 48) and 17 (4; 65) to 36 (31; 54), 47 (39; 57) and 63 (35; 83) ml min(-1) per 100 g, respectively, 6 min after drug administration (P<0.05 endothelin-1 50 microg vs. Control, P<0.01 endothelin-1 100 and 200 microg vs. Control). At the same time CBF decreased in the control and adrenaline group from 36 (21; 41) and 39 (15; 50) to 12 (2; 25) and 24 (15; 26) ml min(-1) per 100 g, respectively, (P<0.05 adrenaline vs. endothelin-1 200 microg). There was no difference in MBF between the treatment groups despite a higher coronary perfusion pressure (CoPP) in the endothelin-1 groups. Restoration of spontaneous circulation could be only achieved in the endothelin-1 50 microg (3 of 7; 43%) and 100 microg (5 of 7; 71%) group. This study suggests that endothelin-1 enhances CBF during CPR better than adrenaline and increases resuscitation success.

Plasma endothelin in patients with acute aortic disease

PURPOSE AND BACKGROUND We investigated the plasma levels of endothelin 1/2 in patients with acute symptoms relating to a known or newly diagnosed aortic aneurysm in order to investigate the possible role of peptides in the development of the disease. METHODS Endothelin 1/2 plasma levels were determined in patients admitted to the emergency unit with suspected acute aortic disease. The history, type of aneurysm, outcome and laboratory findings were determined and compared to endothelin 1/2 levels collected on admission. RESULTS In patients with ruptured aneurysm (n=27) or acute aortic dissection (n=18) the endothelin 1/2 median levels were higher 1.1 (25th and 75th quartile 0.7, 1.7) fmol/ml than in patients (n=20) with pre-existing aneurysm 0.7 (0.4, 1.1) fmol/ml (P=0.013). Patients who died had significantly higher endothelin levels 1.3 (0.8, 1.9) fmol/ml than the survivors 0.8 (0.5, 1.4) fmol/ml (P=0.04). In a logistic regression analysis, only a higher blood pressure on admission was an independent predictor of survival. CONCLUSION Endothelin 1/2 levels are elevated in patients with acute dissection or ruptured aneurysm, but they are not an independent predictor of survival.

Out-of-hospital diagnosis of cerebral infarction versus intracranial hemorrhage

Abstract Objective: To establish a model based on clinical and anamnestic data easily available in the out-of-hospital setting, which facilitates the differential diagnosis between cerebral infarction and intracranial hemorrhage. Design: Retrospective study that simulates a prospective approach. Setting: Emergency Department of the University Hospital in Vienna, Austria. Patients and participants: Data of 224 patients with either intracranial hemorrhage or cerebral infarction were prospectively collected. Uni- and multivariate analysis was performed to identify neurological symptoms and anamnestic data, which were associated with either intracranial hemorrhage or cerebral infarction. Measurements and results: Unilateral weakness or sensory loss was observed more frequently in patients with infarction compared to hemorrhage (69.8% vs 11.9%, P<0.001). The frequency of patients with impaired level of consciousness was significantly higher in the hemorrhage group compared to the infarction group (59.3% vs 3.8%, P<0.001). A multivariate logistic regression analysis showed that hypertension (OR=0.31, 95% CI= 0.12–0.76, P=0.01), diabetes (OR=0.17, 95% CI=0.04–0.68, P=0.01), and unilateral weakness or sensory loss (OR=0.10, 95% CI=0.04–0.26, P<0.001) were significantly associated with cerebral infarction. Impaired level of consciousness was significantly related to hemorrhage (OR=13.41, 95% CI=3.92–45.91, P<0.001). On the basis of the logistic regression analysis, we generated a scoring system for the out-of-hospital diagnosis between infarction and hemorrhage. The values of the score lay between –3 and +3. The probability of infarction increases when the score becomes negative, and the probability for hemorrhage increases when the score becomes positive. Conclusion: Our model is a useful guideline for the differential diagnosis between cerebral infarction and intracranial hemorrhage in the out-of-hospital setting, as it is based on easily available clinical and anamnestic parameters.