[Prevention of spinal hypotension associated with cesarean section by aortocaval compression--left 15 degree table tilt vs. uterine displacement by hand].

Women undergoing elective cesarean delivery were randomly assigned to receive a spinal anesthesia in either the semi-lateral (group SL) position or the supine position with uterine displacement (group UD). After spinal injection, group SL patients were turned to a 15 degrees left lateral supine position, and group UD patients had uterine displacement by hand. Ephedrine 4 mg i.v. was administered in case of nausea/vomiting and/or hypotension, defined as a systolic blood pressure below 100 mmHg. Arm systolic arterial pressure and leg systolic arterial pressure were similar in both groups, but the lowest leg systolic arterial pressure until delivery was significantly lower in the UD group (P < 0.05). Mean ephedrine requirement was significantly less in the SL group (P < 0.05). Apgar scores did not differ, but umbilical artery pH values were significantly higher in patients of the group SL (P < 0.01).

A case of cardiac herniation after extrapleural pneumonectomy for malignant thymoma.

A 44-year-old man underwent radical thymectomy for malignant thymoma 5 years ago. He subsequently underwent right extrapleural pneumonectomy because a right pleural metastatic lesion had developed. The operation was completed uneventfully. Immediately after arrival at the intensive care unit, the patient appeared restless and in pain. His heart rate increased to 140 bpm and then abruptly decreased to 20-30 bpm concomitant with profound systolic hypotension of 30-40 mmHg. Chest X-ray showed that the heart was shifted into the right thorax. Emergent re-thoracotomy was performed and the heart was found to be malrotated and herniated from an upper defect of the pericardial patch in the right thoracic cavity. The heart was returned to the pericardium and the defect was covered with a pericardial patch. The blood pressure and heart rate became stable. He was transferred to the surgical ward from the intensive care unit on the first postoperative day. The rest of the course was uneventful and the patient was discharged on the seventh postoperative day. The incidence of cardiac herniation after extrapleural pneumonectomy following chemotherapy for malignant pleural mesothelioma has been reported to be around 3%. The risk of cardiac herniation should always be considered, especially after extrapleural pneumonectomy.

Respiration-related rhythmic activity in the rostral medulla of newborn rats.

There are at least two respiration-related rhythm generators in the medulla: the pre-Bötzinger complex, which produces inspiratory (Insp) neuron bursts, and the parafacial respiratory group (pFRG), which produces predominantly preinspiratory (Pre-I) neuron bursts. The pFRG Pre-I neuron activity has not been correlated with motor neuron activity in slice or block preparations of rostral medulla. In this study, we attempted to detect pFRG Pre-I activity as motor output in the rostral medulla. We recorded respiratory activity of the facial nerve in the brain stem-spinal cord preparation of 0- to 2-day-old rats. Facial nerve activity consisted of preinspiratory, Insp, and postinspiratory activity. Pre- and postinspiratory activity corresponded well with membrane potential trajectories of Pre-I neurons in the rostral ventrolateral medulla. In response to perfusion of 1 microM DAMGO (a mu-opiate agonist), fourth cervical ventral root (C4) Insp activity was depressed and facial nerve activity continued to synchronize with Pre-I neuron bursts. After transverse sectioning between the levels of the pre-Bötzinger complex and the pFRG, C4 Insp activity recovered within 15 min, but facial nerve activity was inhibited. When DAMGO was applied, C4 Insp activity was inhibited, and rhythmic facial nerve activity recovered. Subsequent elevation of K+ concentration reinduced C4 activity, but facial nerve activity was inhibited. Whole cell recordings in the rostral block revealed the presence of putative Pre-I neurons, the activity of which was synchronized with facial nerve activity. These results show that the rostral medulla, not including the pre-Bötzinger complex, produces Pre-I-like rhythmic activity that can be monitored as facial nerve motor output in newborn rat in vitro preparations.