Yasunobu Kawano

Jugular bulb oxygen saturation under propofol or sevoflurane/nitrous oxide anesthesia during deliberate mild hypothermia in neurosurgical patients.

Sevoflurane and propofol have been widely used as anesthetic agents for neurosurgery. Recent evidence has suggested that the influence of these anesthetics on cerebral oxygenation may differ. In the present study, the authors investigated jugular bulb oxygen saturation (SjO2) during propofol and sevoflurane/nitrous oxide anesthesia under mildly hypothermic conditions. After institutional approval and informed consent, 20 patients undergoing elective craniotomy were studied. Patients were randomly divided to the group S/N2O (sevoflurane/nitrous oxide/fentanyl anesthesia) or the group P (propofol/fentanyl anesthesia). After induction of anesthesia, the catheter was inserted retrograde into the jugular bulb and SjO2 was analyzed. During the operation, patients were cooled and tympanic membrane temperature was maintained at 34.5°C. SjO2 was measured at normocapnia during mild hypothermia and at hypocapnia during mild hypothermia. There were no statistically significant differences in demographic variables between the groups. During mild hypothermia, SjO2 values were significantly lower in group P than in group S/N2O. The incidence of SjO2 less than 50% under mild hypothermic-hypocapnic conditions was significantly higher in group P than in group S/N2O. These results suggest that hyperventilation should be more cautiously applied during mild hypothermia in patients anesthetized with propofol and fentanyl versus sevoflurane/nitrous oxide/fentanyl.

Methemoglobinemia induced by automobile exhaust fumes

Although methemoglobinemia is an uncommon disorder, it should always be considered in the differential diagnosis of cyanosis. Major causes of acquired methemoglobinemia are nitrates, aniline, and analgesics, though rare cases have been reported to have been caused by automobile exhaust fumes. A 24-year-old man had inhaled a large amount of automobile exhaust fumes, intending to commit suicide. He had become unconscious, with dilated pupils and symptoms of cyanosis. Arterial hemoglobin oxygen saturation (SpO2) was 86%, with a methemoglobin level of 44.3% and a carboxyhemoglobin level of 0%, while electrolytes, blood urea nitrogen, creatine, and glucose measurement results were normal. He was treated with methylene blue 250 mg (approximately 4 mg/kg) through a nasogastric tube. Four hours after the treatment, because the methemoglobin level was slightly above normal (2.2%), we added 180 mg of methylene blue. The results of final arterial blood gas analysis were a methemoglobin level of 0.4% and a carboxyhemoglobin level of 0.8%. He recovered uneventfully and returned home by himself the next day. To summarize, we successfully treated, with methylene blue given through a nasogastric tube, a young man who had developed severe methemoglobinemia from inhaling automobile exhaust fumes.

Effects of n-propyl gallate on neuronal survival after forebrain ischemia in rats

THE AIM OF THE STUDY The present study was conducted to assess the effects of intraperitoneal administration of n-propyl gallate (PG) on hippocampal neuronal survival after forebrain ischemia. METHODS Forty male Sprague-Dawley rats were randomly assigned to one of 6 groups. Animals in the PG-I-10, PG-I-8 and PG-S groups received intraperitoneal injection of PG (100mg/kg) 72, 48, 24h and 30 min before severe (10 min) or moderate (8 min) ischemia or sham operation, respectively, while animals in the V-I-10, V-I-8 and V-S groups received the vehicle (10% DMSO) in the same manner. Forebrain ischemia was produced by bilateral carotid occlusion combined with hypotension (35 mmHg) under isoflurane anesthesia. Animals were killed 7 days after reperfusion. Histological assessments were performed using hematoxylin and eosin staining. In separate groups of animals that received PG or vehicle, m-RNA levels of hypoxia-inducible factor 1α (HIF-1α), erythropoietin (EPO) and vascular endothelial growth factor (VEGF) were measured using the reverse transcription-PCR protocol. RESULTS The number of normal neurons was significantly higher in the PG-I-8 group compared with that in the V-I-8 group, whereas it was similar between the PG-I-10 and V-I-10 groups. Animals that received PG had significantly higher levels of HIF-1α, EPO and VEGF expression compared with those that received vehicle. CONCLUSION The results indicated that intraperitoneal administration of PG may have neuroprotective effects in a model of moderate, but not severe, forebrain ischemia in rats.

Use of a laryngeal mask airway to stop a supraglottic air leak which prevented adequate ventilation via a tracheostomy in a patient with cerebral palsy and pneumonia.

We report an adolescent developing ventilation failure due to supraglottic air leakage with the use of an uncuffed hand-made tracheal tube fit to her tracheobronchial deformity. To eliminate the supraglottic air leakage, a size 2.5 laryngeal mask airway (LMA) was inserted into the oral pharynx. Most of air leakage arose from the LMA. Supraglottic air leakage was not detected under mandatory mechanical ventilation following sealing of the 15-mm connector of the LMA with a piece of tape, and the respiratory condition of the patient gradually improved. The combination of a hand-made Y-shaped tube and the LMA was useful in restoring adequate ventilation. In conditions where air leaks through the glottis during mechanical ventilation interfere with adequate ventilation or the maintenance of airway pressure, the use of an LMA may be adequate to stop or significantly decrease the leak.

Life-threatening airway obstruction due to upper airway edema and marked neck swelling after labor and delivery

BACKGROUND AND OBJECTIVES Airway changes generally occur in normal gravidas; however, these changes could cause critical situations in specific populations. OBJECTIVES This article presents the case of a difficult airway patient that went into shock because of atonic bleeding after vaginal delivery for stillbirth. CASE REPORT A 32-yr-old woman with atonic bleeding after vaginal delivery for stillbirth was transferred to our hospital. She manifested shock, and her respiratory condition was progressively deteriorating. Airway obstruction caused by neck swelling and pharyngolaryngeal edema was apparent. We tried tracheal intubation using direct and indirect laryngoscopes. However, it turned out that insertion of the laryngoscopic devices to the oral cavity was impossible. After several attempts using the Trachlight™, successful intubation was finally made. After hysterectomy, she was admitted to the intensive care unit (ICU) and treated for five days. At discharge from the ICU, her Mallampati score was I-II. Her body weight decreased 60 kg to 51 kg during ICU stay. CONCLUSIONS We believe that concomitant attacks of labor and delivery and fluid resuscitation probably worsened upper airway and neck edema enough to cause acute airway obstruction and difficult laryngoscopy.

A Case of Ventilation Error Due to Malfunction of Scavenging System for Anesthetic Gases

症例は根治的前立腺全摘術が予定された67歳男性. 入室前に日本麻酔科学会指針による麻酔器の始業点検を行った. 導入時やや麻酔器を動かした. 用手換気で呼気時に換気圧が上昇する傾向がみられたが挿管し, 胸郭の上昇は十分であった. 人工呼吸に切り替えたが, 胸郭の下降が悪く換気のたびに呼気圧が上昇した. 手動換気に切り替えたが同様でありadjustable pressure limiting valve (APL弁) を開放しても気道内圧は下がらず, 回路と挿管チューブの接続を離すことでのみ呼出がなされた. 余剰ガス吸引ラインのねじれ閉塞によるものであることが判明し, これを開放すると解消された. 硬膜外麻酔施行時に麻酔器の位置を動かしていたことがねじれの原因と考えられた.