Continuous positive airway pressure (CPAP) vs. intermittent mandatory pressure release ventilation (IMPRV) in patients with acute respiratory failure.

Intermittent Mandatory Pressure Release Ventilation (IMPRV) is a positive pressure spontaneous breathing ventilatory mode in which airway pressure is released intermittently and synchronously with patient's spontaneous expiration in order to provide ventilatory assistance. Eight critically ill patients free of any factor known to alter chest wall mechanics (group 1) and 8 critically ill patients whose spontaneous respiratory activity was markedly altered by a flail chest, or by a C5 quadraplegia and/or by the administration of opioids (group 2) were studied prospectively. CPAP and IMPRV were administered to each patient in a random order during a 1 h period using a CESAR ventilator. Gas flow, tidal volume, tracheal pressure, esophageal pressure, end-expiratory lung volume and hemodynamic parameters were measured. In group 1 patients, the ventilatory assistance provided by IMPRV was associated with a significant decrease in spontaneous tidal volume whereas all other respiratory parameters remained unchanged. In group 2 patients, IMPRV increased minute ventilation from 8.0 +/- 2.61/min to 12.2 +/- 1.81/min (p less than 0.05), decreased PaCO2 from 46 +/- 7.3 mmHg to 38 +/- 6.8 mmHg (p less than 0.05) and reduced respiratory frequency from 21 +/- 10 bpm to 14 +/- 5.7 bpm (p less than 0.07). These results show that IMPRV provides significant ventilatory assistance to patients with mild acute respiratory failure either by decreasing patient's contribution to minute ventilation or by increasing alveolar ventilation in presence of respiratory depression of central or peripheral origin.

[Intra-articular analgesia after arthroscopy of the knee]. / Analgésie intra-articulaire après arthroscopie du genou.

In 33 patients the authors compared two protocols for postoperative analgesia after elective arthroscopy of the knee. One group (n = 11) received plain bupivacaine 0.25% by intra-articular administration. Another group (n = 11) received by the same route a mixture of bupivacaine 0.25% with fentanyl 50 micrograms. The last group (placebo group: n = 11) received the same volume of saline. The combination of bupivacaine with fentanyl reduced postoperative pain more effectively than plain bupivacaine and the analgesic effect was still present 9 hours after the arthroscopy.

Accuracy of radial arterial pressure measurement during surgery under controlled hypotension.

BACKGROUND: Radial arterial pressure underestimates the pressure in the aorta in several clinical situations. A central-to-radial pressure gradient was attributed to intense vasodilation. The aim of this study was to evaluate the accuracy of radial pressure monitoring during controlled hypotension achieved with profound arterial vasodilation. METHODS: Ten patients with ASA physical status I and II undergoing maxillofacial surgery under general anesthesia were enrolled in this prospective study. Radial and femoral arteries were cannulated and connected to a pressure monitoring system. Controlled hypotension was achieved with an infusion of nicardipine titrated to maintain MAP between 50 and 60 mmHg. Simultaneous radial and femoral systolic, mean and diastolic arterial pressures were recorded before, during and after controlled hypotension. Results were expressed as mean +/- SD. Concomitant radial and femoral pressures were compared by a paired Student's test, P < 0.05 being significant. RESULTS: In all, 150 sets of arterial pressures measurement were obtained. There were no statistically significant differences between radial and femoral arterial pressures measured before, during or after controlled hypotension. CONCLUSION: Radial arterial pressure is an accurate measure of central arterial pressure during controlled hypotension achieved with arterial vasodilation.

[Severe multiple injuries. Strategy and results. Experience at the Hôpital de la Pitié in 1988 and 1989]. / Polytraumatisés graves. Stratégie et résultats. Expérience de l'Hôpital de la Pitié 1988 et 1989.

In our series of 97 patients with multiple in juries observed in 2 consecutive years (1988-1989), we have selected only the most severe injuries, of which the patients died within 48 hours, and those that required a long stay in the intensive care department. On admission, we recorded 49 cases of stage II or more severe coma, and 67% of patients under respiratory assistance with an instable hemodynamic state. Out of the 44 deaths recorded, 30 subjects were comatose from the beginning. The justifies the confrontation of 3 specialist teams in 2/3 of cases. The specific recruitment of the hospital and the selection of the most severe cases of these "people under a death sentence" for the study shows a heavy toll of mortality (45,4%), including 60% on the first day. The main cause of death is head injuries (81%). The multivisceral and infectious consequences of long-lasting, heavy intensive care and pulmonary or myocardial contusions account fort secondary deaths in 25% of the patients who had survived. Emergent neurosurgical operations are exceptional, but a neurosurgeon's opinion is always essential. Orthopedic surgical issues are not specific, but the frequency of spinal lesions must be emphasized (27,2%). In this series, 85% of the patients with multiple trauma presented with a lesion of the locomotive apparatus and underwent emergent surgery in every second case in satisfactory conditions. Severe thoracic and maxillofacial lesions requiring surgery are rare. Abdominal lesions are more frequent (17%) and must be dealt with in priority, but they rarely cause death. On the contrary, lesions to the major blood vessels and retroperitoneal compound lesions have a very poor prognosis.(ABSTRACT TRUNCATED AT 250 WORDS)