Ma zui xue za zhi = Anaesthesiologica Sinica最新文献

The influence of the endothelium on the vasodilator effect of ketamine and its possible mechanism of action on intracellular calcium levels were investigated. We conducted experiments in vitro on canine basilar arteries precontracted with 5-HT and with potassium at high concentrations. Ketamine (10(-6) to 10(-3) M), added cumulatively, relaxed both 5-HT and high-K(+)-induced contraction of basilar arteries (with or without endothelium) in a dose-dependent manner. The ED50s of ketamine for relaxation of 5-HT and high-K(+)-induced contraction for intact endothelium were 3 x 10(-4) M and 6 x 10(-4) M, respectively, and for denuded preparations, 7 x 10(-4) M and 15 x 10(-4) M, respectively. Methylene blue, which blocks the release and/or the effect of endothelium derived relaxing factor, significantly attenuated the relaxation effect of ketamine on the basilar artery. Our results indicate that the endothelium may be responsible for a part of the vasodilator effect of ketamine. We also examined the effect of pretreatment of basilar artery with ketamine (5 x 10(-4) M) on intracellular calcium levels when contraction was induced by 5-HT or by high K+ concentrations. Ketamine significantly inhibited the phase of the contraction induced by high K+. Thus, the vasodilator effect of ketamine may be mediated by inhibition of calcium influx and by the release of EDRF.

Prevention and treatment of postoperative nausea and vomiting with ephedrine, droperidol and metoclopramide have been reported to be effective. To further investigate their efficacy, 100 pediatric patients scheduled to undergo inguinal hernioplasty on ambulatory basis were divided into five groups, namely, group 1: normal saline (iv) control; group 2: ephedrine 0.5 mg/kg, (im); group 3: droperidol 50 micrograms/kg. (iv); group 4: ephedrine 1 mg/kg. (im); group 5: metoclopramide 0.15 mg/kg. (iv). At the end of surgery, each patient received the drug treatment according to the specified group to which he was randomly assigned. The occurrence of postoperative nausea and vomiting was recorded in the recovery room and inquired at home by telephone within 24 h following surgery by a blinded observer. The authors found that there were no significant differences between the control group and ephedrine groups with whichever dose that was used in the prevention of postoperative nausea and vomiting. Droperidol and metoclopramide were effective in dealing with problem in comparison with control group (p less than 0.05). However, metoclopramide was more suitable than droperidol for pediatric outpatient based on duration of somnolence, return of orientation, and time of discharge.

Dose-response relationship of mini-dose intrathecal morphine (0.025-0.125 mg) for analgesia after Cesarean section was studied. Sixty-three patients were randomly divided into six groups by the following intrathecal morphine injection: group 1 (0 mg), group 2 (0.025 mg), group 3 (0.05 mg), group 4 (0.075 mg), group 5 (0.1 mg), and group 6 (0.125 mg). The selected dose of morphine mixed with 2 ml 0.5% hyperbaric bupivacaine (10 mg) was administered intrathecally to induce spinal anesthesia. The mean analgesia duration in each group was 3.6 +/- 2.0, 10.6 +/- 7.1, 17.3 +/- 13.8, 25.6 +/- 7.5, 33.9 +/- 10.1, and 39.5 +/- 11.9 h respectively (mean +/- SD). In morphine groups, duration of analgesia was significantly longer (p less than 0.05) than control group (0 mg), and the first 24 h pain scores were also lower (p less than 0.01). Furthermore, a significant linear dose-response relationship between analgesic duration and the dose of intrathecal morphine was revealed (y = 3.28 + 295.5x, r2 = 0.64, p less than 0.05). Among morphine groups, analgesic quality was significantly better in patients in groups 4-6 than those in group 2 and 3 (p less than 0.05), so as in the proportion of effective analgesia in the first 24 h (p less than 0.01). Neonatal condition was not adversely affected by such mini-dose of intrathecal morphine. The most common maternal adverse effect observed was pruritus, and its incidence was significantly greater in groups 3-6 than in the control group (p less than 0.05). However, no significant difference was observed among all morphine groups.(ABSTRACT TRUNCATED AT 250 WORDS)

High-dose fentanyl has become a popular anesthetic agent for cardiac anesthesia because of its cardiac stability. Little attention has yet been paid to the relationship between the dose and problems during the early postoperative period. This study was designed to investigate whether higher doses of fentanyl combined with diazepam would influence the early-stage of postoperative conditions. Sixteen patients scheduled for elective coronary artery bypass graft (CABG) surgery were studied. All of them had adequate cardiac performance, and were randomly divided into two groups, 9 in Group I and 7 in Group II. Group I received fentanyl (less than 100 micrograms/kg) combined with diazepam (less than 0.2 mg/kg). In Group II the doses of both drugs were greater than that used in Group I. The cardiovascular changes, the maximal infusion rates of dopamine, nitroglycerin (NTG), and sodium nitroprusside (Nipride) were observed. Meanwhile, the awakening time from anesthesia, the time of extubation, and the duration of stay in the intensive care unit (ICU) were also recorded. The results showed that there were no significant differences between both groups regarding the factors studied except the maximal infusion rate of Nipride and the awakening time of post-anesthesia. We suggest that higher doses of fentanyl combined with diazepam can reduce the dosage of vasodilator but do not prolong the time of extubation and stay in ICU.

The purpose of the study is to probe the situation of venous air embolism (VAE) and the accompanying complications occurring in Chinese parturients in Taiwan during Cesarean section. Sixty ASA physical status class I-II parturients who were subjected to cesarean section under regional anesthesia were evaluated. The sensor of the Doppler device was placed on the anterior chest to detect the rumbles of air when it came to pass, and simultaneously the signs and symptoms following VAE were observed. Our results demonstrated that the usual or normal Doppler heart sound changed in 38 parturients out of 60 (63.3%), and the alteration occurred very often when the uterus was being incised (81.6%), or sutured (97.4%), and concurred strong correlation with such signs and symptoms such as chest tightness or precordial pain (78.9%), shortness of breath (60.5%), and change of heart rate or blood pressure (86.8%). The method of anesthesia (spinal or epidural block) did not have effect on the occurrence of VAE, but different surgical approaches and different positions in which the patients were posed during operation did apparently bring about VAE of variable degree. Besides, supplying of oxygen could mitigate the symptoms produced by VAE. Consequently, the application of Doppler monitor during Cesarean section can detect VAE earlier and more efficiently and thus provides information timely treatment.

The distribution of somatostatin (SST) throughout the nervous system suggests that this tetradecapeptide may play a physiological role in CNS in the mediation of analgesia. The present study was undertaken to evaluate the antinociceptive properties of intrathecal (IT) injection of SST in the comparison of morphine sulfate (MS) in a primate model. The study was conducted after institutional approval and adhered to the regulations of the animal research committee. Seven adult monkeys (Maccaca cyclopis Swinhoe) weighing 4-6 kg were used. In each animal a L5 laminectomy window was created to facilitate IT injection. No neurological damage from surgery was noted. With the monkey standing in a specially constructed cage, all animals randomly received the following agents at one-week interval: (1) MS 1 mg, IT; (2) SST 50 micrograms, IT; (3) SST 250 micrograms, IT; and (4) SST 250 micrograms, IT + intramuscular (IM) naloxone 400 micrograms. The measured withdrawal latency (HPWL) was converted to the maximal percentage effect (MPE %) for comparison. The HPWL was measured at predrug and 5, 15, 30, 45, 60, 90 and 120 min after injection. Venous blood sample was obtained every 15 min to determine the plasma SST level by radioimmunoassay (RIA) technique in group 3 only. The results showed that MS (1 mg, IT) produced potent antinociception (MPE 100%) for more than 2 h. Intrathecal SST 50 micrograms, however, induced mild antinociception (MPE 43%) for only a short period and a 5-fold larger dose (250 micrograms) did not significantly change the nociceptive threshold with MPE only up to 47%.(ABSTRACT TRUNCATED AT 250 WORDS)

The laryngeal mask airway (LMA), a new type of airway, when it is inserted blindly into the hypopharynx forms a seal around the larynx and allows easy and convenient spontaneous or controlled positive pressure ventilation. A clinical application of the LMA to 70 surgical patients in our hospital have been evaluated. LMA was successfully applied to 68 (97%) patients who all received general anesthesia with unobstructed controlled ventilation. The patency of the airway did not change throughout the course of anesthesia. There were 2 patients whose airway was obstructed at the first attempt due to downfolding of epiglottis; in one of them the obstruction was confirmed by flexible fibreoptic laryngoscopy. Subsequent placement was successful in these 2 patients. Insertion failure was seen in 2 patients respectively due to small mouth and excessive salivation. The placement of LMA does not require laryngoscopy and there is no fear of misplacement in the esophagus. It becomes obvious that the LMA would substantially gain a place in the armamentarium in anesthesia and we think that its use would be of interest to anesthesiologists.

The pressor response associated with laryngoscopy and endotracheal intubation may be harmful to patients with ischemic heart disease, hypertension or cerebrovascular disease. The Brain laryngeal mask airway can be inserted blindly and avoid the need for laryngoscopy. Our preliminary study compared the pressor response of tracheal intubation (T group) with that of laryngeal mask insertion (L group) in 19 and 33 hypertensive patients respectively. We also divided the patients of L group into sub-groups I (n = 16) and II (n = 17). All patients in T group and sub-group I were induced with fentanyl, thiopentone and succinylcholine while in subgroup II patients were induced with the same dosage of thiopentone and succinylcholine without fentanyl. The changes of blood pressure and heart rate exhibited a similar but attenuated pattern of response with laryngeal mask insertion in comparison with tracheal intubation. We also found no significant difference in pressor response between sub-group I and sub-group II in L group. In sum, laryngeal mask insertion may therefore offer some advantages over tracheal intubation in the anesthetic management of hypertensive patients in whom less pressor response is of particular concern.