Mechanism of analgesia induced by hypnosis and acupuncture: is there a difference?

Hypnosis and acupuncture can alleviate experimentally induced pain but the mechanism of analgesia remains unclear for both techniques. Experimental pain was induced by cold pressor test (CPT) in 8 male volunteers. Analgesic effect of hypnosis (HA) and acupuncture (AA) was assessed before and after double-blind administration of placebo or naloxone, in a prospective, cross-over study. We found that pain intensity was significantly lower with HA as compared with AA, both with naloxone (P less than 0.001) and placebo (P less than 0.001). Within HA or AA groups, pain scores did not differ significantly when naloxone or placebo was administered. During AA, however, pain scores were similar to control values when naloxone was given (P = 0.05) but decreased significantly with placebo (P less than 0.002). Analog scales for pain intensity and pain relief showed a good correlation (r = 0.94). Plasma levels of beta-endorphins did not change significantly in any combination. Heart rate, peripheral arterial blood pressure and skin conductance were very insensitive indices to assess pain intensity or relief, as well as intensity of acupuncture stimulation or depth of hypnotic trance. We conclude: (1) HA and AA can significantly reduce pain from CPT, and HA is more effective than AA: (2) HA and AA are not primarily mediated by the opiate endorphin system; and (3) plasmatic levels of beta-endorphins are not significantly affected by either HA or AA nor by naloxone or placebo administration.

[Per- and postoperative risk status in pulmonary surgery]. / Situation de risque per- et postopératoire en chirurgie pulmonaire.

Better understanding of pulmonary physiology over the last few years has permitted a more effective control of gaz exchanges during pulmonary surgery. The introduction of one-lung anesthesia offers a greater margin of safety to the patient and improved surgical conditions, and helps avoid hypoxic episodes. Modern management of ventilation during pulmonary surgery unquestionably requires the use of full invasive monitoring: central venous pressure, pulmonary pressures (in specific situations) and radial arterial pressure (systolic, mean and diastolic pressures). Pulse oximetry and measurement of end-tidal carbon dioxide are also indispensable. Complete monitoring and frequent determinations of arterial blood gases allow continuous adjustments of the ventilation of the dependent and independent lungs. Placement of epidural thoracic catheters for postoperative analgesia represents another improvement. This technique alone permits rapid and complete recovery of pulmonary function after pulmonary surgery.

[Assessment of the efficacy and tolerance of a benzodiazepine antagonist (Ro 15-1788)]. / Evaluation de l'efficacité et de la tolérance d'un antagoniste des benzodiazépines (Ro 15-1788).

The aim of this study was to evaluate the efficacy and the tolerance of Ro 15-1788, a specific benzodiazepine antagonist, in reversing the effects of midazolam. Six healthy male volunteers (mean age 32 +/- 3 years; mean weight 75.5 +/- 5 kg) took part in this study. Two of the three following drugs: midazolam (0.15 mg X kg-1), Ro 15-1788 (0.1 mg X kg-1) or placebo, diluted in 10 ml isotonic saline, were injected intravenously in 15 s at 5 min intervals in a double-blind manner in each subject during six randomized sessions: midazolam-placebo; Ro-placebo; placebo-midazolam; placebo-Ro; midazolam-Ro; Ro-midazolam. At least four days were allowed between each session for each subject. The evaluation of the effects on the central nervous system was as follows. At the time of injection of the first drug and, if possible, at the time of injection of the second drug, the subject was asked to count aloud to 150. The following variables were timed: start of dysarthria, cessation of counting, abolition and duration of absence of the ciliary reflex and duration of induced sleep. Retrograde and anterograde amnesia were evaluated by the recall of a playing card and a number. Haemodynamic effects (variations of systolic and diastolic pressures and pulses rate) as well as respiratory ones (apnoea) were also studied.(ABSTRACT TRUNCATED AT 250 WORDS)

Noninvasive evaluation of breathing pattern and thoraco-abdominal motion following the infusion of ketamine or droperidol in humans.

The authors compared the respiratory effects of an intravenous infusion of ketamine (1 mg X kg-1) with droperidol (0.1 mg X kg-1), or placebo on three different occasions in a double-blind, randomized fashion in eight healthy volunteers. Breathing pattern, thoraco-abdominal motion, end-expiratory positions of the rib cage and abdomen, arterial hemoglobin oxygen saturation (SaO2), and end-tidal carbon dioxide concentration (FECO2) were continuously measured with noninvasive techniques. During the 1-h monitoring period following drug injection, droperidol produced occasionally significant but clinically unimportant differences in respiratory variables when compared with placebo. In contrast, ketamine induced a significant (P less than 0.001) and persistent increase in minute ventilation (+75%) from 5 to 20 min after start of infusion by increasing both the driving (i.e., tidal volume/inspiratory time [VT/Ti]) and the timing (i.e., inspiratory time/total respiratory cycle time [Ti/Ttot]) components of ventilation (Milic-Emili J, Grunstein MM: Chest 70 (Suppl): 131-133, 1976). This was obtained without any significant change in end-expiratory positions or change in relative rib cage contribution to tidal volume. Despite multiple apneic episodes observed with ketamine, the subjects maintained a stable SaO2 and FECO2, indicating no resting respiratory depression. This study, performed with a noninvasive respiratory monitoring technique, confirms that droperidol infused over 5 min at a clinically used dosage does not cause respiratory depression in healthy subjects, whereas ketamine produces an important ventilatory stimulation.

Clinical evaluation of a specific benzodiazepine antagonist (RO 15-1788). Studies in elderly patients after regional anaesthesia under benzodiazepine sedation.

The efficacy, usefulness and side effects of RO 15-1788 (RO), a specific benzodiazepine (BZD) antagonist, have been evaluated. Sixty-two patients (ASA I-III, mean age 72 +/- 9 yr) scheduled for urological surgery under regional anaesthesia and BZD sedation received placebo or RO in a randomized, double-blind fashion at the end of the procedure, following sedation with midazolam. When compared with placebo, RO improved alertness and collaboration for 15 min, and suppressed anterograde amnesia for 60 min. No major side effect was noted, although five patients became anxious after administration of RO. Two cases of a paradoxical reaction to midazolam were treated successfully by RO.

Absence of benefit of incentive spirometry in low-risk patients undergoing elective cholecystectomy. A controlled randomized study.

To determine the potential benefit of incentive spirometry, which has been advocated to prevent pulmonary complications after upper-abdominal surgery, we compared a group of patients receiving incentive spirometry to another group receiving no specialized postoperative respiratory care. Forty patients in the American Society of Anesthesiologists' class 1 and 2 who were undergoing cholecystectomy (through right subcostal incision) were included in the study and were randomly allocated to one of the two groups. Patients receiving incentive spirometry were encouraged by a specialized respiratory physiotherapist to breathe deeply for five minutes hourly, 12 times daily, for three postoperative days. No statistically significant difference between the two groups was found in the radiologic evidence of postoperative pulmonary complications, arterial oxygen pressure, spirometric measurement, and clinical evaluation at the second or fourth postoperative day (or both). In particular, deterioration on the chest x-ray film at the fourth postoperative day was observed in eight of 20 patients in the group receiving incentive spirometry and in six of 20 in the control group. Our study confirms the postoperative deterioration of respiratory function after upper-abdominal surgery and demonstrates the lack of therapeutic values of incentive spirometry in these patients at low risk for pulmonary complications.

[Prevention of hyperkalemia and muscular fasciculations induced by suxamethonium]. / Prophylaxie de l'hyperkaliémie et des fasciculations musculaires induites par le suxaméthonium.

Suxamethonium has not yet been replaced to ease endotracheal intubation despite its many undesirable side effects. Hyperkalemia and muscle pain are two such side effects; they are not reliably prevented by giving, before suxamethonium, a small dose of a non depolarizing muscle relaxant, although it does decrease muscle fasciculations. The purpose of this study was to compare with a control group three different pretreatments of these undesirable effects of suxamethonium: 1) hyperventilation, 2) calcium chloride which are accepted means of lowering the serum potassium, and 3) magnesium sulfate which has been reported in a non-controlled study to decrease muscle fasciculations. The study was performed in 40 patients (10 per group) in whom changes of plasma potassium and calcium levels were determined and muscle fasciculations measured by an objective method. Serum electrolyte variations and the quantity and duration of muscle fasciculations were similar in all groups. None of the pretreatments administered had any adverse effect on the neuromuscular block induced by suxamethonium.

Respiratory depressant effects of different doses of midazolam and lack of reversal with naloxone--a double-blind randomized study.

Conflicting data concerning the ventilatory effects of benzodiazepines may be caused by the large variability in investigational conditions. Respiratory effects of three different intravenous doses of midazolam (0.05 mg/kg, 0.1 mg/kg, 0.2 mg/kg) and placebo were measured in a double-blind and randomized fashion in eight healthy volunteers. The respiratory variables were analyzed by means of a noninvasive method, thereby avoiding interferences associated with the stimulating effects of mouthpiece and nose clip. After injection of midazolam, tidal volume decreased by 40% with the three doses and respiratory frequency increased to the same extent, minute ventilation remained constant. Only the largest dose of the drug produced a significant decrease (P less than 0.05) in O2 saturation that was related to the longer duration of apnea. Intravenous naloxone (0.015 mg/kg) injected 5 min after midazolam did not change any measured respiratory or hemodynamic variable. We conclude that the respiratory effects of midazolam are poorly dose related and not reversed by naloxone. The observed compensatory increase in respiratory frequency which is not noted in other studies, is probably related to the noninvasive measurement technique used.

Incest and pelvic pain: the social worker as part of a research team.

This article suggests the valuable role a social worker can play as a researcher on a multidisciplinary team. In a study conducted by a gynecologist, a social worker, a psychiatrist, and a psychologist, women experiencing chronic pelvic pain were found to be profoundly affected by factors other than organic disease, such as traumatic early childhoods, psychopathology, and incest in a significant number of cases.

Midazolam and anaesthesia.

By virtue of its physico-chemical properties and its rapid biotransformation, midazolam is an important addition in certain areas in anaesthesia. Of particular importance are its good local tissue tolerance after intramuscular injection, the absence of venous irritation, and the rapid start of metabolism with good control of action. Midazolam is suitable for both oral and intramuscular administration as premedication in anaesthesia. The compound can also be used for the induction of anaesthesia in combination with analgesics.

Comparative haemodynamic and respiratory effects of midazolam and flunitrazepam as induction agents in cardiac surgery.

30 cardiac surgical patients were investigated for comparing the respiratory and haemodynamic repercussions of induction of anaesthesia with either flunitrazepam or 8-chloro-6-(2-fluorophenyl)-1-methyl-4H-imidazo[1,5-a] [1,4]benzodiazepine (midazolam, Ro 21-3981, Dormicum). The patients were premedicated with morphine, 0.15 mg/kg i.m., and divided into two groups: one group receiving flunitrazepam 0.03 mg/kg, the other midazolam 0.15 mg/kg injected i.v. over a 15-s period. The induction time and the respiratory depression were similar in both groups. A similar decrease in systolic, diastolic and mean arterial pressures was noted, with maximum decrease of mean arterial pressure of 21% 5 min after injection of flunitrazepam, and of 19% after injection of midazolam. Midazolam produced a significant but transient pulse acceleration of 4% 1 min after the injection, while flunitrazepam produced a moderate decrease of the heart rate. These results indicate that in cardiac surgical patients midazolam produces a moderate respiratory and cardiovascular depression similar to flunitrazepam.

Respiratory depression by midazolam and diazepam.

The purpose of this study was to examine the respiratory depression produced by diazepam and by midazolam. Ventilatory and mouth occlusion pressure responses to CO2 were measured in eight healthy volunteers before and after the intravenous administration of 0.3 mg/kg of diazepam and 0.15 mg/kg of midazolam. The mean ventilatory response to CO2 (mean +/- SEM) decreased after administration of diazepam or midazolam from 2.0 +/- 0.2 to 1.3 +/- 0.1 1.min-1/torr or from 2.1 +/- 0.2 to 1.4 +/- 0.1 1.min-1/torr, respectively. In the same volunteers, the mouth occlusion pressure responses decreased from 0.54 +/- 0.05 to 0.30 +/- 0.04 cm H2O/torr after midazolam and from 0.67 +/- 0.12 to 0.28 +/- 0.07 cm H2O/torr after diazepam. When compared with the control slopes of the ventilatory and mouth occlusion pressure responses, the drug slopes were significantly different. Respiration was similarly depressed after diazepam and after midazolam. That both the ventilatory and mouth occlusion pressure responses to CO2 are equally depressed by intravenous injections of midazolam and of diazepam at equipotent doses suggests a direct depression of the central respiratory drive by these drugs.

I.V. midazolam as an induction agent for anaesthesia: a study in volunteers.

The central nervous and cardiovascular effects of midazolam 0.15 mg kg-1 were studied in 20 healthy, unpremedicated volunteers (10 male and 10 female). No important side-effects were noted and the venous tolerance to midazolam was excellent. Three minutes after injection mean systolic arterial pressure decreased from 121 +/- (SEM) 2 mm Hg to 115 +/- (SEM) 2 mm Hg and diastolic pressure from 78 +/- 2 to 70 +/0 2 mm Hg (P < 0.05), and these effects persisted for at least 20 min. Heart rate increased from 77 +/- 4 beat min-1 to 90 +/- 3 and 88 +/- 3 beat min-1 and 3 min after the injection (P < 0.05). Anterograde amnesia (40 +/- 3 min duration) and drowsiness (lasting 128 +/- 23 min) were observed in all subjects. Loss of the eyelash reflex and apnoea were observed more often in the male group than in the female subjects. Midazolam 0.15 mg kg-1 was not sufficient to induce anaesthesia reliably in healthy unpremedicated volunteers.