[Hyperventilation syndrome before induction of and after awakening from general anesthesia].

Hyperventilation syndrome has often occurred as a reaction to anxiety and stress. We experienced hyperventilation syndrome before induction of and after awakening from general anesthesia. A 53-year-old woman with no central nervous and psychiatric disease was scheduled for left total hip arthroplasty under general and epidural anesthesia. After entering the operating room, she was breathing faster and deeper than necessary. She complained of dyspnea, and the numbness and sweating of her lower extremities. We found that she had the same experience on her dental treatment. We diagnosed her as preoperative hyperventilation syndrome. Twenty minutes after she had become relaxed, we could insert the lumbar epidural catheter, and tracheally intubate following anesthesia induction with fentanyl, thiopental, and vecuronium. Anesthesia was maintained using inhalation of sevoflurane and epidural anesthesia with ropivacaine. As end-tidal carbon dioxide (EtCO2) value was 18 mmHg after anesthesia induction, we controlled the ventilator to regulate EtCO2. The operation was finished in 54 minutes successfully without a special event. She was extubated because there was no clinical problems. The total anesthesia time was 2 hours and 4 minutes. Postoperatively in the recovery room, she breathed fast and complained of dyspnea and the numbness of her extremities again. The arterial blood gas analysis showed reduced arterial partial pressure of carbon dioxide tension with resulting respiratory alkalosis. We diagnosed her as postoperative hyperventilation syndrome. We let her breathe in and out of a vinyl bag continuously and injected antipsychotic medication haloperidol intravenously. After injection of haloperidol 3 mg for 30 minutes, she recovered from hyperventilation. Hyperventilation syndrome before general anesthesia could occur postoperatively again. We supposed that her hyperventilation syndrome is induced by anxiety and stress of operation before induction and again after awakening from general anesthesia. Haloperidol could be effective for repeated hyperventilation syndrome induced by psychogenic factors during perioperative period.

[Isorhythmic dissociation during sevoflurane anesthesia].

Arrhythmia during general anesthesia occurrs occasionally as a result of the effect of inhalation anesthetic agent on cardiac conduction. We experienced a case of atrioventricular junctional rhythm (AVJR) during maintenance of general anesthesia with sevoflurane. A 61-year-old woman with normal preoperative electrocardiogram was scheduled for right total knee arthroplasty and autologous iliac crest bone graft under general and epidural anesthesia. After inserting the lumbar epidural catheter, endotracheal intubation was performed following anesthesia induction with fentanyl, thiopental, and vecuronium, and anesthesia was maintained using inhalation of nitrous oxide and sevoflurane, and epidural anesthesia with ropivacaine. Forty minutes after starting operation, the dissociated and upright P-wave approached the QRS complex, remaining within QRS complex for several beats, and then reappeared from it electrocardiographically. ST segment was transiently depressed from baseline. The R-R interval and waveform of the QRS complex did not change. The sequence was repeated. The blood pressure had been held slightly depressed but waveform of pulse oxymetry (SpO2) did not change during this phenomenon. We diagnosed it as AVJR, which is classified into isorhythmic dissociation. After discontinuation of sevoflurane at the end of the operation, isorhythmic dissociation returned to sinus rhythm. Sevoflurane could induce atrioventricular conduction disturbance leading to isorhythmic dissociation of AVJR. We should be aware that hypotension can result from isorhythmic dissociation during sevoflurane anesthesia.

[General anesthesia for two patients taking methylphenidate (Ritalin)].

We experienced anesthesia care for two patients taking methylphenidate (Ritalin), which is a central nervous system stimulant of amphetamine analogues, usually administered for narcolepsy or refractory depression. The proper dose of methylphenidate is 20-60 mg per day. General anesthesia with epidural anesthesia was administered to both cases for total hip replacement. One patient could discontinue taking methylphenidate five days before the operation, but the other patient could not. Both cases needed more anesthetics than usual on induction, but very stable condition could be maintained during and after the operations. We consider that it is possible to perform general anesthesia safely for patients taking a usual dose of methylphenidate.

Change in the concentration of neutrophil elastase in bronchoalveolar lavage fluid during anesthesia and its inhibition by cholesterol sulfate.

UNLABELLED: Cholesterol sulfate (CS) in the gastrointestinal tract exhibits a mucosal protective activity in mouse ulcer model. To clarify the possible role of CS for protection from the epithelial injury due to neutrophil elastase in the tracheobronchi, the authors determined the concentrations of CS and neutrophil elastase in bronchoalveolar lavage fluid (BALF) from patients under anesthesia, and they examined the inhibitory activity of CS toward neutrophil elastase. The concentrations of CS and neutrophil elastase were determined by thin-layer chromatography and enzyme-linked immunosorbent assaying, respectively, and the effect of CS on the activity of elastase was determined with a chromogenic substrate. CS was found to be present in human lung, tracheal mucosa, and BALF, and a high synthesis of it was detected in the tracheal mucosa, in which cellular cholesterol sulfotransferase was induced depending on the density of tracheal cells. Among lipids in the tracheal mucosa, only CS was demonstrated to exhibit inhibitory activity toward neutrophil elastase, a powerful erosive agent in inflammation. The secretion of elastase from neutrophils into BALF was stimulated during the course of general anesthesia. In contrast, the amount of CS in BALF gradually decreased during anesthesia. On immune-precipitation of neutrophil elastase in BALF, CS was detected in the immune precipitate, which indicates a possible association of CS with neutrophil elastase in BALF. CONCLUSION: CS, which is a major acidic lipid in the tracheobronchial epithelium, might function as an epithelial inhibitor toward neutrophil elastase secreted in response to several stimuli such as anesthesia.