Early post-operative hyperbaric oxygen therapy modifies neutrophile activation.

BACKGROUND/AIMS: To investigate the effect of acute hyperbaric oxygen therapy (HBOT) on post-operative sinusoidal endothelial cell (SEC) damage caused by activated neutrophils. METHODOLOGY: 12 non-cirrhotic patients (Group H), who underwent elective hepatectomy for liver cancer, were given 2 courses of HBOT: 2.0 atm with inhalation of 100% oxygen, for 60 min, at 3 hours and 24 hours after hepatectomy; they were then compared with the 12 patients (Group C) who had been treated to maintain normal hemodynamic values. RESULTS: In group H, peak levels of polymorphonuclear leukocyte elastase (PMNE) and thrombomodulin (TM) were clearly diminished and delayed compared to Group C. All subjects in Group C showed more than a 10% increase in CD18 12 hours after surgery; however, in Group H, the elevation of CD18 expression was clearly suppressed compared to Group C. No patient in Group H had post-operative hyperbilirubinemia or hepatic failure; however, 3 had post-operative hyperbilirubinemia and 1 had intraperitoneal infection in Group C. CONCLUSIONS: Our results provide direct evidence that HBOT, especially at 3 hours after hepatectomy, has favorable effects on the activation of neutrophiles decreasing SEC injury.

[Effects of endotracheal intubation on the trachea--usefulness of the evaluation by MRI].

Using an MRI apparatus, we observed the effects of endotracheal intubation on the trachea by measuring T1 value before and after an operation in ten surgical cases. T1 value of the anterior wall at the level of the first tracheal ring was 275.8 +/- 58 msec, and that of the posterior wall was 346.8 +/- 72 msec. The patients were all intubated under general anesthesia. Anesthesia was maintained with inhalation anesthesia such as nitrous oxide-oxygen-enflurane with the aid of vecuronium bromide. Periods of intubation varied between 80 to 46 minutes, and averaged 270 +/- 112 minutes. After the extubation, T1 value showed 312 +/- 62 msec at the anterior wall and 395 +/- 82 msec at the posterior wall. In the case of the posterior wall, T1 value was significantly prolonged compared with that of the pre-intubation period. Prolongation of T1 value is assumed to be related to the increase of tissue free water demonstrating the occurrence of tissue edema. From the findings that T1 value might be prolonged by endotracheal intubation, we conclude that the MRI apparatus is useful for investigating the effects of the intubation procedure on the trachea.

[Veno-arterial ECLA (extracorporeal lung assist) for severe respiratory failure due to meconium aspiration].

A full term newborn female, 3262g, aspirated meconium at birth and began to suffer from severe hypoxia and acidosis due to progressing pneumonitis, pneumothorax and pneumomediastinum. She also had severe hypotension and anuria. Venoarterial ECLA with a Kolobow membrane lung via the right internal jugular vein and the right common carotid artery was initiated. Blood gas parameters and blood pressure improved, and urine output increased to normal. ECLA permitted a reduction in FIO2 and airway pressure of mechanical ventilation, as well as frequent lavage of the lung. As the physical condition improved, the bypass flow was gradually decreased from 200 ml.kg-1.min-1 at the start to 130 ml.kg-1.min-1 for maintenance, then to 25 ml.kg-1.min-1 at the end. Bleeding throughout the ECLA for 69 hours could be minimized by a meticulous control of the activated coagulation time with a minimum dose of heparin and the transfusion of fresh frozen and platelet rich plasma. After ECLA, the carotid artery was simply ligated, and mechanical ventilatory support was carried out for 5 days. Her condition improved and she left the hospital without any neurological sequelae. ECLA will become an effective means of life support for a baby with severe MAS irresponsive to conventional ventilatory support.

Evaluation of conventional weaning criteria in patients with acute respiratory failure.

We evaluated the reliability of conventional weaning criteria from a ventilator during 33 weaning trials on 25 patients with acute respiratory failure (ARF). Of 13 criteria, a ratio of maximal voluntary ventilation to minute ventilation (MV) >2, a vital capacity >12 ml.kg(-1), a spontaneous respiratory rate <25 breaths.min(-1), and a MV <10 l.min(-1) appeared to be useful for predicting successful weaning outcome. However, even using those criteria, there were many falsely-negative cases. The alveolar-arterial P(O)(2) gradient <350 mmHg at an F i(O)(2) 1.0 was not useful as a predictor of weaning outcome. The present study demonstrates that conventional criteria are frequently inaccurate for predicting weaning outcomes and suggests that the use of some of these criteria may unnecessarily prolong the length of ventilator support. Since ventilation of most patients with poor oxygenation can be successfully discontinued by placing them on a continuous positive airway pressure system, these results suggest that the improvement of oxygenation is not an indispensable prerequisite for weaning from mechanical ventilators.