Masui. The Japanese journal of anesthesiology
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The effects of hemodilution on cerebral hemodynamics and oxygen consumption during nonpulsatile hypothermic cardiopulmonary bypass (CPB) were investigated in 16 patients undergoing elective open heart surgery under CPB. They were divided into 2 groups; high (25%) (H) and low hematocrit (15%) (L) groups according to the hematocrit values during CPB. Simultaneous measurements of blood flow velocity in the middle cerebral artery (VMCA) and oxygen tension in the jugular venous bulb (PjvbO2) were performed at prebypass, bypass, and post bypass periods. ⋯ However, there were no significant differences in VMCA and PjvbO2 between the two groups at any period. These findings suggest that increased cerebral blood flow may compensate the decreased oxygen content due to the hemodilution during CPB. Therefore, the profound hemodilution up to 15% of hematocrit is considered to be a safe technique during CPB.
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Comparative Study
[Blood gas changes during laparoscopic cholecystectomy--comparative study of N2O pneumoperitoneum and CO2 pneumoperitoneum].
During laparoscopic cholecystectomy by alternative insufflation of nitrous oxide and carbon dioxide, the changes of blood gas tensions were measured and analyzed in 12 patients. During N2O insufflation, PaO2 decreased by about 25 mmHg and PaCO2 was unaltered compared with the values before pneumoperitoneum. ⋯ We considered that decrease in PaO2 during N2O insufflation was associated with not only uneven ventilation/blood flow ratios but also with the reduction in the alveolar O2 tension caused by the diffusion of N2O absorbed from the peritoneum. PaCO2 increases during CO2 insufflation because CO2 is absorbed from the peritoneum, and is not excreted entirely through the lungs.
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Median nerve somatosensory evoked potentials (SEPs) were recorded over neck (N13) and scalp (N20) in 18 neurologically normal subjects anesthetized with isoflurane, sevoflurane or enflurane for abdominal or lower limb surgery. SEP recordings were made at 0.5, 1.0 and 1.5 MAC of each volatile agent without nitrous oxide. These three agents did not change N13 latency and amplitude. ⋯ During enflurane anesthesia N20 amplitude was smaller than that at increased in dose related manner. At 1.0 MAC of enflurane N20 amplitude was smaller than that at 0.5 MAC, but further decrease was not produced at 1.5 MAC. The data suggest that effects of sevoflurane on SEPs were more similar to those of isoflurane than those of enflurane.
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Randomized Controlled Trial Clinical Trial
[Evaluation of a pressure and volume-relief instrument (modified Brandt's rediffusion system) to prevent increase in endotracheal tube cuff pressure].
Nitrous oxide diffuses into the endotracheal tube cuff and then overexpand the cuff. This causes upper airway obstruction and trauma in intubated patient during general anesthesia. We evaluated the efficacy and a safety of a pressure and volume-relief instrument (modified Brandt's rediffusion system), which can easily be made by ourselves, to prevent increases in endotracheal tube cuff pressure. ⋯ Pressure of endotracheal tube cuffs was monitored and recorded until the extubation. Time interval until the pressure of tube cuffs increased more than 23 mmHg, which inhibit the local circulation on the tracheal cartilage, in rediffusion group (274.7 +/- 95.9 min) was significantly longer than the duration in control group (64.7 +/- 23.5 min). We conclude that the rediffusion instrument is effective and safe to prevent the rise in the pressure of an endotracheal tube cuff.
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Randomized Controlled Trial Comparative Study Clinical Trial
[A better method to attach an endotracheal tube to the stylet of the Bullard laryngoscope].
The Bullard laryngoscope with its introducing stylet is useful in a variety of patients with airway problems, but it poses difficulties in some cases where an endotracheal tube (ETT) catches on the ary-epiglottic fold and cannot be advanced into the trachea. This difficult may be avoided by slightly angulating the tip of the ETT so that it is directed in a better alignment toward the rima glottis. The efficacy of the two methods of angulation was studied. ⋯ Intubation on the first attempt was successful in 56% of group 1, 83% in group 2 and 100% in group 3. The patients in groups 1 & 2 in whom first attempt failed were all successfully intubated on the second trial with the method used in group 3. This method (180 degrees rotation of the ETT on the stylet), is applicable to any ETT with or without the Murphy eye.