Detection of myocardial ischemia in vitro by computed tomography

The applicability of CT in the delineation of ischemic myocardium is defined. Twenty-six dogs had their left anterior descending coronary artery occluded, and radiolabeled microspheres were injected into the left atrium to measure myocardial blood flow. From 30 minutes to 7 weeks after coronary occlusion the hearts were excised and scanned in a CT head scanner. An unbiased observer divided selected CT scans slices into normal, abnormal, and borderline areas of attenuation coefficients; these were correlated with blood flow measurements and a progressive decrease in flow from normal to borderline and borderline to abnormal segments was found. As early as 2 hours after coronary arterial occlusion, areas of reduced attenuation coefficient, corresponding to regions of reduced blood flow, were seen. Areas of increased attenuation were seen in regions containing microcalcifications and fibrosis in several longer term experiments. Areas of reduced blood flow were visible immediately after coronary arterial occlusion with intravenous iodinated contrast material (1 ml/kg). CT detection of regions of reduced blood flow defined by radiolabeled microsphere is a promising means of detecting and sizing myocardial infarcts.     

Catastrophic injuries in pole-vaulters

Pole vaulting is a unique sport in that athletes often land from heights ranging from 10 to 20 feet. We retrospectively reviewed 32 catastrophic pole-vault injuries that were reported to the National Center for Catastrophic Sports Injury Research between 1982 and 1998. The purpose of this study was to determine the mechanisms of injury so that preventive strategies can be implemented. Information was obtained by means of a telephone interview with someone familiar with the accident. All injuries occurred in male athletes at an average age of 17.5 years; 31 were catastrophic head injuries and 1 was a thoracic spine fracture that resulted in paraplegia. Three common mechanisms were identified: 17 (53%) athletes landed with their body on the landing pad and their head on the surrounding hard ground, 8 (25%) landed in the vault box after being stranded at the height of the jump, and 5 (16%) completely missed the landing pad. The mechanism of injury in the remaining two athletes was unknown. The accident resulted in death in 16 (50%) athletes and in permanent disability in 6 (19%). Increasing the minimum landing pad size and enforcing the rule requiring soft surfaces adjacent to the landing pads are the primary recommendations for preventing injuries. The authors discuss other rule and equipment changes that may help reduce the occurrence of future injuries.     

Non-invasive pressure support ventilation in severe community-acquired pneumonia

OBJECTIVE: To explore three aspects of non-invasive pressure support ventilation (NIPSV) applied by face mask to patients with acute respiratory failure (ARF) due to severe community-acquired pneumonia (CAP): (1) the initial acute effects on respiratory rate, gas exchange and hemodynamics, (2) the clinical course and outcome during ICU and hospital stay, (3) the nursing workload as measured by the daily PRN 87 (Project Research in Nursing) score. SETTING: Medical ICU, University Hospital. DESIGN: Prospective, observational study. PATIENTS: Patients without any prior history of chronic lung disease, consecutively admitted to the ICU to receive NIPSV for ARF due to severe CAP. MEASUREMENTS AND RESULTS: (means +/- SD): Twenty-four patients aged 49+/-17 years, admission APACHE II 13+/-5, were included. Admission PaO2/FIO2, alveolar-arterial oxygen difference (DA-aO2) and PaCO2 were 104+/-48, 447+/-120 and 40+/-10 mmHg, respectively. All patients were normotensive. During the initial NIPSV trial respiratory rate decreased from 34+/-8 to 28+/-10 breaths/min (p < 0.001) and arterial oxygenation improved (PaO2/FIO2 104+/-48 vs 153+/-49, DA-aO2 447+/-120 vs 370+/-180 mmHg, p < 0.001) while PaCO2 remained unchanged. There were no hemodynamic effects. Subsequently, a total of 133 NIPSV trials were performed (median duration 55 min, range 30-540 min) over 1-7 days. No complication occurred during NIPSV. Sixteen patients were intubated (66%) 1.3+/-1 days after inclusion. Upon inclusion, the patients who were subsequently intubated were older (55+/-15 vs 37+/-12 years) and more severely hypoxemic (63+/-11 vs 80+/-15 mmHg, p < 0.05) than those not requiring intubation. Eight patients died (33 %), all in the intubated group. Median lengths of stay in the ICU and hospital were longer in intubated patients (ICU 16 days, range 3-64 vs 6 days, range 3-7, p < 0.05; hospital 23 days, range 9-77 vs 9.5 days, range 4-42, p < 0.05). Mean daily total PRN points were stable throughout the NIPSV period and were not different between the groups. Only 14% of PRN points resulted from respiratory therapy interventions. PRN score was higher during the first 24 h following intubation than during the first 24 h of NIPSV (278+/-55 vs 228+/-24 points, p < 0.05). CONCLUSION: Despite initial improvement in arterial oxygenation with NIPSV in patients with ARF due to severe CAP, the intubation rate is high. However, the more favorable outcome and shorter ICU and hospital stays when intubation is avoided, as well as the short delay required to assess the success or failure of NIPSV warrants a trial of NIPSV in this setting. The nursing workload remains stable during NIPSV and does not result predominantly from respiratory therapy interventions.