Journal of anesthesia
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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.
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Journal of anesthesia · Apr 1991
Clinical Trial Controlled Clinical TrialEvaluation of alkalinized lidocaine solution in brachial plexus blockade.
The effect of alkalinization of lidocaine solution in brachial plexus blockade was evaluated in a double blind study. Commercial 1.5% lidocaine with epinephrine 1 : 200,000 (pH 5.72) was compared with an alkalinized solution of lidocaine (pH 7.12). 10 mg.kg(-1) of each solution was administrated by the axillary perivascular technique in 34 adult patients scheduled for elective surgery. The onset and spread of sensory blockade and the intensity of motor blockade were determined. ⋯ Also the analgesic onset in the radial and musculocutaneous nerves was significantly faster than the other two nerves ( P < 0.05 and P < 0.01). Furthermore, the intensity of motor blockade was greatly potentiated when alkalinized lidocaine solution was employed. There was no significant increase in plasma concentration of lidocaine in patients who were given alkalinized solution.
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Journal of anesthesia · Apr 1991
Respiration by tracheal insufflation of oxygen (TRIO) at high flow rates in apneic dogs.
Tracheal insufflation of oxygen (TRIO) is a technique in which oxygen is introduced into the trachea at a constant flow rate via a catheter advanced to the level of the carina. We studied the effects of flow rates (0.5, 1.0, 1.5 and 2.0 l.kg(-1).min(-1)) on arterial blood gases during TRIO in 6 apneic dogs. The constant flow was administered through the tip of a catheter (I. ⋯ TRIO, at a flow rate of 3 l.kg(-1).min(-1), was able to maintain normocarbia over 4 hr. The mean Pa(O)(2) and Pa(CO)(2) at 4.0 hr were 465 +/- 77 and 41 +/- 4 mmHg. Although the mechanism of pulmonary gas exchange during TRIO is unclear, our study is the first to document that normocarbia can be maintained by high-flow TRIO in apneic dots.