Yoshikazu Sai

Comparison of responses of canine pulmonary artery and vein to angiotensin II, bradykinin and vasopressin

Responses to angiotensin II, bradykinin and arginine vasopressin were compared in helical strips of canine pulmonary arteries and veins. Angiotensin II contracted the artery but relaxed the vein strip. The artery contraction was augmented by indomethacin and aspirin and was abolished by losartan. The vein relaxation was not affected by endothelium denudation but was abolished by the cyclooxygenase inhibitors, a prostaglandin I2 synthase inhibitor and losartan. The bradykinin-induced artery relaxation was inhibited by endothelium denudation, NG-nitro-L-arginine (L-NA) or indomethacin and abolished by their combined treatment. The vein relaxation produced by bradykinin was endothelium-independent and was abolished by indomethacin. Vasopressin produced a slight relaxation in the arteries, which was abolished by endothelium denudation and L-NA. The vein relaxation produced by vasopressin was abolished by endothelium denudation and combined treatment with L-NA and indomethacin. It may be concluded that (1) activation of angiotensin AT1 receptor subtype in smooth muscle produces contraction and also relaxation due to prostaglandin I2 release; the former predominates over the latter in the artery, whereas only the latter is operative in the vein, (2) the bradykinin-induced relaxation is due to nitric oxide (NO) from the endothelium and prostaglandin I2 from subendothelial tissues in the artery and solely to prostaglandin I2 in the veins, and (3) the vasopressin-induced relaxation is mediated by endothelial NO in the artery, and NO and prostaglandin I2 in the vein.

Pituitary apoplexy following cholecystectomy

A case of pituitary apoplexy, which presented with hyperaesthesia in the distribution of the ophthalmic division of the left trigeminal nerve and a left sixth nerve palsy following cholecystectomy, is reported. Computed tomography and magnetic‐resonance imaging revealed a large intrasellar mass which extended laterally into the left cavernous sinus and showed evidence of old and recent haemorrhage within the tumour. This case demonstrates that patients who present with unusual neurological symptoms involving the cranial nerves after general anaesthesia, should undergo neurological and radiological investigations.

Anesthetic management of an extremely obese patient

We present the case of a morbidly obese woman, with a body mass index (BMI) of 73.7 kg·m−2, who had a gynecological operation under combined general and epidural anesthesia. The patients trachea was intubated, using a fiberscope, while she was breathing spontaneously after the intravenous injection of fentanyl and propofol as sedatives. Anesthesia was maintained with intravenous propofol and epidural mepivacaine. When the gynecologist placed a sponge in the abdominal cavity to retract the bowel, the patient experienced severe arterial deoxygenation and mild hypotension, due to massive atelectasis of the left lung. Both oxygenation and perfusion were corrected by the removal of the sponge and with the placement of a pillow under the patients left shoulder. The atelectasis resulted from compression of the left lung by the fatty mediastinum and by the diaphragm being pushed up by the sponge. The hypotension resulted from impaired venous return and hypoxia. The patient suffered no perioperative complications other than atelectasis and a surgical-site infection. Key factors that contributed to the favorable outcome of this patient included a careful tracheal intubation technique, the choice and dose of anesthetic agents, immediate correction of the factors leading to atelectasis, early ambulation, and prophylaxis for deep vein thrombosis.

Effect of halothane, fentanyl, and ketamine on the threshold for transpulmonary passage of venous air emboli in dogs.

We assumed that the capacity of the lungs to filter gas bubbles would vary as a function of anesthetic management. The effects of halothane (1% inspired concentration [group 1, n = 8]), fentanyl (100 micrograms/kg IV, followed by 1 micrograms.kg-1.min-1 [group 2, n = 7]), and ketamine (10 mg/kg IV, followed by 0.2 mg.kg-1.min-1 [group 3, n = 6]) on the passage of bolus injections of air across the pulmonary circulation were studied in dogs by using transesophageal echocardiography to detect air in the left atrium or the aorta, or both. The thresholds for bolus air detection during halothane, fentanyl, and ketamine administration were 0.05 mL/kg (range 0.01-0.1), 0.5 mL/kg (range 0.2-1.0), and 0.35 mL/kg (range 0.1-0.5), respectively. We conclude that the threshold during fentanyl- or ketamine-induced anesthesia was significantly higher than during halothane-induced anesthesia. Therefore, halothane interferes with the capacity of the lungs to filter air from the pulmonary circulation.

Comparison of the in vitro caffeine-halothane contracture test with the Ca-induced Ca release rate test in patients suspected of having malignant hyperthermia susceptibility.

AbstractPurpose. We compared the results of the in vitro caffeine-halothane contracture test (CHCT) according to the protocols of the North American Malignant Hyperthermia Group (NAMHG) and the European Malignant Hyperthermia Group (EMHG) with the Ca-induced Ca release (CICR) rate test in the same patients with suspected malignant hyper thermia (MH). Methods. Five normal controls and 16 patients suspected of having MH susceptibility were studied. Muscle biopsies were usually obtained from the musculus vastus lateralis. Diagnostic cutoff points and procedures for CHCT protocols were as described in the original and renewal versions of NAMHG and EMHGs. The CICR rate test was performed according to the protocol reported by Endo et al. Results. All five normal controls and two patients with abortive MH, two with postoperative hyperthermia, and three with high serum creatine kinase levels were normal in the three tests. Three patients with MH reactions and one patient with a history of masseter spasm were classified as MH positive according to NAMHG criteria and MH susceptible and MH equivocal according to EMHG criteria. There were five cases with discordant results between the CHCT and CICR rate tests. Conclusion. We propose that muscle biopsy for diagnosis of MH susceptibility should combine the CHCT with the CICR rate test, which may identify the defective site of Ca release channels.

A new leak test for specifying malfunctions in the exhalation and inhalation check valve.

problem exists that there is fractional extraction of epinephrine in forearm tissues in the range of 25%-50% (1,2). Measurement of norepinephrine concentrations from the antecubital vein is also subject to the influence of local factors that both add and remove norepinephrine from forearm tissues. Accordingly, we acknowledge that the pulmonary artery is the best sampling site for measuring epinephrine concentrations.and that arterial measurements provide a good alternative. However, the medical condition of our patient population did not ethically justify the use of either pulmonary or radial arterial catheters, so antecubital venous sampling was used instead. In taking this limitation into consideration, we wish to emphasize that we evaluated the percentage of change of both epinephrine and norepinephrine concentrations in response to a standardized stimulus (tracheal intubation) and measured the within-patient serial changes of both catecholamines over a very short period ( 4 0 min). We observed that the changes in catecholamine concentrations paralleled the cardiovascular response in both the control and experimental groups, suggesting a reasonably reliable reflection of the body‘s response to stress. Reflecting on our study design, we concur with the recently expressed opinion of Dr. Herd that “epinephrine is not secreted from organs other than the adrenal medulla. Accordingly, few assumptions need to be made concerning the pattern of epinephrine levels in the forearm venous blood” (1). Donald R. Miller, MD Raymond J. Martineau, MD Kathryn Hull, RN Department of Anaesthesia

Comparison of the effects of pancuronium and vecuronium in canine coronary and renal arteries.

Background Pancuronium has sympathomimetic actions but does not change or lowers systemic blood pressure in some studies of anesthetized humans and dogs. The present study was done to determine the actions and mechanisms of action of pancuronium on coronary and renal arteries other than those as a sympathomimetic agent. Methods Helical strips of coronary and renal arteries from mongrel dogs were suspended in oxygenated, warmed Ringer‐Locke solution, and changes in the isometric tension were recorded. In some strips, transmural electrical stimulation (5 Hz for 40 s) was applied to activate perivascular adrenergic nerves. Results Pancuronium (10 sup ‐7 to 10 sup ‐5 M) caused dose‐dependent relaxation in coronary and renal arteries contracted with prostaglandin (PG) F2 alpha, whereas no significant response was induced with vecuronium. The relaxation was endothelium independent and abolished by indomethacin or tranylcypromine, a PGI2 synthase inhibitor. Transmural electrical stimulation caused coronary arterial relaxation, which was augmented by pancuronium and vecuronium. Desipramine also increased the response, and additional potentiation of the response was not elicited by pancuronium and vecuronium. In renal arteries, electrical stimulation caused contraction, which was also augmented by pancuronium and vecuronium. With desipramine treatment, these muscle relaxants did not potentiate the response. Endothelium‐dependent coronary arterial relaxation caused by bradykinin was not affected by pancuronium. Conclusions Pancuronium‐induced relaxations in canine coronary and renal arteries appear to be mediated by PGI2 released from subendothelial tissues. Potentiations by pancuronium and vecuronium of the response to adrenergic nerve stimulation are expected to be due to an inhibition of the norepinephrine uptake but not to facilitated release of the amine.

Airway Scope®-assisted nasotracheal intubation

low success rates for tracheal placement and high potential for airway trauma at room temperature [4, 5]. The success rates for tracheal placement in the Mingo paper are 28% at room temperature and 46% at 10 C, both unacceptably low. We suggest that neither the 1997 nor the 2006 version of the Portex single use introducer should be used in clinical practice. The Portex Venn reusable introducer has a high success rate for tracheal placement and (even when cooled to 0 C) is less likely to cause airway trauma than any of the tested single use introducers. It should be noted that there was a wide range of peak forces exerted at the tip by the Portex Venn reusable introducer at room temperature when held at 20 cm from the tip. The values varied from 0.6 to 1.3 N for 15 introducers tested [4]. It therefore seems sensible to have a Portex Venn introducer in the refrigerator irrespective of the environmental temperature. This cooled introducer should be used if the introducer at room temperature can not be inserted into the trachea. However, clinicians should be aware that when the Portex Venn reusable introducer is placed in the fridge before use, the associated increase in stiffness that improves the incidence of successful tracheal placement [1] results in increased peak forces at the tip [2] and an associated increased risk of airway trauma.

Bar Code System Applied to Operation Center of University Hospital

Bar code system has been applied to the Operation Center to control the circulation of many kinds and large quantities of materials existed in the Operation Center.