Journal of anesthesia
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Journal of anesthesia · Oct 1991
External cardiac massage using a hand-powered chest compressor on dogs with ventricular fibrillation.
We devised a hand-powered portable chest compressor for external cardiac massage. The purpose of this study was to assess the efficacy and safety of this device in comparison to manual chest compression in dogs with ventricular fibrillation. Five out of 7 dogs that received manual chest compression during cardiopulmonary resuscitation (CPR) were successfully resuscitated. ⋯ Minimum arterial pressure during CPR was higher in dogs receiving mechanical chest compression than those receiving manual chest compression. This study reveals that the hand-powered chest compressor is equally efficient for external cardiac massage as manual cardiac massage. Moreover, this device can be useful in a situation where manual compression has to be interrupted, such as during litter transport of the patient, and so on.
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A modified thermodilution catheter (KATS catheter) capable of monitoring continuous cardiac output by thermodeprivation and preserving its conventional function was devised. The KATS catheter has a thermistor incorporated closer to the tip of the catheter in addition to the usual thermistor used for conventional thermodilution. This additional thermistor is heated by a constant electric current but is capable of measuring its own temperature. ⋯ Calibration can be derived from a cardiac output measurement by the usual thermodilution method with the same catheter. The KATS catheter readings correlated significantly with conventional thermodilution values and electromagnetic flowmeter readings in anesthetized dogs. Continuous cardiac output measurement by the KATS catheter appears to be a promising technique.
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We examined the effects of enflurane on the diaphragmatic function in 15 pentobarbital-anesthetized, mechanically ventilated dogs. They were divided into three groups of five animals each, according to the administered concentration of enflurane. The diaphragmatic function was assessed from transdiaphragmatic pressure (Pdi) and integrated diaphragmatic electromyography (Edi) developed at functional residual capacity against an occluded airway during bilateral supramaximal phrenic nerve stimulation at 0.5, 10, 20, 50 and 100 Hz under quasiisometric condition. ⋯ Edi during 50 Hz stimulation was also decreased at 1 MAC. Relative changes in Edi following enflurane administration were greater than the corresponding changes of Pdi. These results demonstrate that enflurane impairs diaphragmatic function through its inhibitory effects on neuromuscular transmission.
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Journal of anesthesia · Apr 1991
A close relationship between post-tetanic twitch and train-of-four responses during neuromuscular blockade by vecuronium.
The relationship between post-tetanic twitch (PTT) and train-of-four (TOF) responses after intravenous administration of vecuronium were studied using EMG in 20 patients under nitrous oxide and enflurane anesthesia. After the initial dose (0.2 mg.kg(-1)) of vecuronium, the detectable first twitch of PTT (PTT(1)) always preceded that of TOF (TOF(1)) with the mean time interval of 10.7 +/- 2.6 min. ⋯ The magnitude of TOF(2) was slightly lower than that of PTC(20). These results suggest that there is a close relationship between these two types of response, and by evaluating not only PTC but also the magnitude of each PTT, the recovery of TOF responses can be predicted and its extent be estimated fairly accurately.
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Laryngeal mask airway (LMA) insertion was tried in 120 pediatric cases, from 2 months to 12 years of age. Initial indications for LMA were the same as for a face mask, except for two additional conditions; anticipation of difficulty with intubation and difficulty in management by a face mask. Size 2 LMA was used in the vast majority of cases. ⋯ LMA-aided tracheal intubation can be extremely useful in obtaining endotracheal airways. Non-blind techniques can be used with LMA to increase safety. LMA is a very useful addition to pediatric anesthesia practice.