The influence of anaesthetic technique upon the immune response to hysterectomy. A comparison of propofol infusion and isoflurane.

Earlier studies on propofol have shown increased percentages of T helper cells after minor surgery. In this study, the effects of propofol infusion anaesthesia on the immune response were compared with those of combined isoflurane anaesthesia in 30 patients (median age 47 years, ASA 1-2) undergoing major surgery. The total dose of propofol in the propofol infusion group of 15 women was 860 mg (range 540-1520 mg) and the median end-expiratory isoflurane concentration in the combined isoflurane group of 15 women was 0.6% (range 0.5-0.8). The following were measured; leucocyte and differential counts; percentages of lymphocyte subpopulations (CD3, CD4, CD8, CD19, CD16 and HLA-DR+CD3); phytohaemagglutinin-, concanavalin A-, and pokeweed mitogen-induced and unstimulated lymphocyte proliferation; plasma interleukin-6; serum group II phospholipase A2, C-reactive protein and cortisol concentrations. Measurements were made pre-operatively, at the end of the operation and on the first and fifth postoperative days. No statistically significant overall differences were observed in the immune response between the groups. The serum cortisol response was weaker in the propofol group than in the isoflurane group (p < 0.05). Time-related changes were seen within the groups.

[Mechanisms of the effect of general anesthesia with barbiturates on immunity]. / Mekhanizmy vliianiia obshchei anestezii barbituratami na immunitet.

The effect of short-acting barbiturates on the number of theophylline-resistant and theophylline-sensitive T-lymphocytes in donors and patients with lung cancer on the function of spontaneous and induced donor regulators as well as the concentration of cyclic nucleotides and T-lymphocytes in donors has been studied in vitro. The effect of general anesthesia with barbiturates on the number of lymphocyte populations and subpopulations in the peripheral blood of somatically healthy patients with minimum surgical trauma has also been assessed. These studies as well as previous investigations serve the basis for elucidating the impact of general anesthesia with barbiturates on the immunity. It is recommended to identify the nature of immunodepression in patients with preoperative immune deficiencies.

Use of atropine in connection with oral midazolam premedication.

The clinical significance of intramuscular premedication with 0.01 mg/kg of atropine in a procedure involving oral benzodiazepine premedication (15 mg midazolam the evening before surgery and on the morning of surgery) was investigated in a double-blind study. As far as sedation, apprehension, excitement, dizziness, emesis, and headache were concerned, there were no significant differences between group 1 (atropine) and group 2 (placebo) patients; however, both during and after anesthesia patients in group 1 had less excessive salivary secretion (especially during extubation). As a result of sympathetic overactivity, patients in group 1 had an increased heart rate and an increased incidence of supraventricular tachycardia. In group 1 intravenous infusion proved more difficult, and in addition, the patients complained more of subjective side effects (dry mouth). There was no significant correlation between the radioimmunologically measured serum concentrations and the clinical effects of atropine measured just before the induction of anesthesia. Substantial interindividual differences were found in these serum levels. From the anesthetist's viewpoint, atropine has both beneficial effects (antisecretory) and unwanted effects (cardiovascular effects). For the patient atropine caused only subjective unwanted effects. Midazolam, a new short-acting, sedative benzodiazepine derivatives, can be used without atropine as an oral premedicant.

Segmental epidural analgesia - a modern method for safe and effective management of labor pains.

The effect and safety of segmental epidural analgesia (SEA) were investigated in three groups of parturients totaling 250. Three comparative groups were also created. In 50 primigravidae, the analgesic effect was good in 90%, moderate in 8%, and poor in only 2%. The opinion of midwives on analgesic effect was also similar. Investigation of the duration of labor showed that the duration of both first and second stages was longer in SEA groups than in nonepidural groups. However, with more liberal use of oxytocin in the SEA group this difference disappeared. The SEA did not lead to more malpositions than were present in the nonepidural groups. Nevertheless, the rate of instrumental deliveries was approximately three times higher in the SEA groups than in nonepidural groups (15.2% vs 4.7%, respectively). No difference between the groups occurred when Apgar scores at 1 and 5 min were investigated.

Tofizopam: a benzodiazepine derivative without sedative effect.

In a single-blind randomized study 47 patients received 100 mg tofizopam orally as a premedication before minor surgery, 50 patients received placebo, an 50 patients no premedication. Both tofizopam and placebo significantly increased the subjective sedative effect of the patients, but there was no significant difference in any of the measured parameters between tofizopam and placebo. In another double-blind randomized study, 49 patients received 100 mg tofizopam three times orally before gynecologic operations and 49 patients received placebo. Compared with placebo, tofizopam had a stimulant action and decreased the excitement of the patients. The effect of tofizopam on apprehension + excitement was significantly better than that of placebo. According to these results, the active component seems to be an unknown metabolite of tofizopam causing a clear drug effect only after repeated oral doses of the parent drug. A slow accumulation in the central nervous system is also possible. In the drug response a wide interindividual variation was found.

Comparative study of the clinical effects of tofizopam, nitrazepam and placebo as oral premedication.

In a double-blind randomized study 47 patients received tofizopam 100 mg orally the night before operation, and 100 mg on the morning of operation; 49 patients received nitrazepam 5 mg and 50 patients received placebo. On average the nitrazepam group slept better and were better sedated than the tofizopam or placebo groups. Compared with placebo or nitrazepam, tofizopam decreased the excitement of the patients. The effect tofizopam on apprehension and excitement was significantly better than those of placebo or nitrazepam. Nitrazepam, but not tofizopam, significantly decreased the induction requirements of thiopentone.

A comparative study on the clinical effects of flunitrazepam and lorazepam.

The clinical effects of flunitrazepam and lorazepam as oral premedicants were tested in a double-blind study in 81 gynaecological patients. Flunitrazepam showed a higher sedative effect (p < 0.05), but in regard to other parameters tested, no significant differences were found (sleep, apprehension, excitement, dizziness, emetic effect, headache, increase or decrease in systolic blood pressure, increase in pulse rate, venipuncture). In 9 per cent of the patients treated with lorazepam, a prominent muscular relaxation with slurred speech was observed, but in none of the cases treated with flunitrazepam. Our results support the earlier claims of flunitrazepam's relatively specific sedative property, but on the whole the difference in the clinical effects of these benzodiazepine derivatives is not marked.

Flunitrazepam versus placebo premedication for minor surgery.

The clinical effects of oral flunitrazepam (2 mg on the night before operation followed by 2 mg on the morning of operation) and placebo as premedicants were tested in a double-blind study in 81 gynaecological patients. The separate or total concentrations of flunitrazepam and its demethylated metabolite in plasma (measured by gas chromatography) were correlated with the clinical effects of flunitrapam premedication, assessed both sugjectively and objectively. In most parameters tested (sleep on the night before operation, sedation, apprehension, headache, pulse rate), there was a positive, significant difference between the flunitrazepam group (n = 44) and the placebo group (n = 37). No significant difference was found between the two groups in emetic effect, excitement, systolic blood pressure increase, and vene-puncture, but the patients receiving flunitrazepam felt significantly more dizziness. The temperature of the left forefinger before, during and after the anaesthesia did not vary significantly between the two groups. There was no correlation between the plasma concentration of flunitrazepam and its demethylated metabolite (separate or total concentrations) and any of the parameters tested before induction of anaesthesia. Flunitrazepam is a new oral premedicant with prominent sedative and anxiolytic actions. When the drug is given as a sedative on the night before operation, followed by a second dose on the morning of operation, the beneficial effects last for at least 8 hours after the second dose.

Oral oxazepam as a premedicant in minor surgery.

The clinical effects of oral oxazepam and placebo as premedicants were tested in a double-blind study in 40 gynaecological patients. The gas chromatographically measured concentrations of the active, unconjugated forms of oxazepam in the plasma were correlated with the clinical effects of oxazepam, assessed both subjectively and objectively. The insertion of an intravenous cannula was significantly more difficult (p less than 0.001) in the placebo premedicated group. However, there was no significant difference between the two groups in the cutaneous temperature of the left forefinger. Of the eleven parameters tested there was a significant difference between the oxazepam and placebo group in the quality of sleep on the night before operation (p less than 0.05) and in the degree of preoperative sedation (p less than 0.01). The combined results of the eleven parameters of the oxazepam group also differed positively significantly from the placebo group (p less than 0.01). There was no obvious relationship between the plasma concentration and clinical effect of oxazepam.

Nitrazepam premedication for minor surgery.

Sixty-one patients received nitrazepam 5 mg by mouth on the night before operation, followed by 2.5 mg given on the morning of operation and were compared with 60 patients who received no premedication. All were undergoing either therapeutic abortion, by dilatation and curettage, or explorative curettage. The plasma concentrations of nitrazepam were determined by gas chromatography and compared with the clinical effects of the drug. The premedicated patients slept better on the night before operation, and were more sedated and less apprehensive. Headache was more frequent following nitrazepam. There was no significant difference between the groups in respect of dizziness and nausea. The unpremedicated patients had a faster average heart rate. There was no obvious relationship between the plasma concentration of nitrazepam and the quality of sleep, degree of sedation, apprehension, excitement or headache.

Halothane anaesthesia in caesarean section.

The safety and efficacy of halothane anaesthesia were investigated in 97 caesarean sections using 0.4-0.6% halothane added to a mixture of 61 N2O/3-4 1 O2. The administration of halothane was initiated before intubation and terminated immediately prior to delivery. Only one patient reported memories from the operation. The mean Apgar score 1 min after delivery (8.5) was significantly better than that (8.2) in 100 caesarean sections in which a mixture of 71 N2O/3 1 O2 was used. In 17 caesarean sections, the halothane concentrations were examined after 0.9% halothane had been given for exactly 1 min after intubation. It was found that halothane reached and passed the placenta after only 1 min. The levels in the maternal artery and umbilical vein were comparable. The levels in the maternal artery, maternal vein and umbilical vein were markedly higher than in the umbilical artery, which indicated an accumulation of halothane in the foetal tissues. However, due to the vigour of the newborn, halothane concentrations 10 min after birth were very low. The half-life of halothane in the maternal circulation was approximately 1 min with the described method of administration. Blood gas determinations, which were made in seven newborns, proved satisfactory.