Ketamine and oxycodone in the management of postoperative pain.

Relief of pain, whether post-traumatic or postoperative, is a prerequisite for the prevention of its deleterious effects on the whole organism. Unalleviated pain also increases the victim's or patient's anxiety and apprehension, which in turn increase the intensity of the pain. In the management of pain, opiates have maintained their position as the most common form of analgesic therapy despite the many side effects associated with their use. This double-blind study compared the analgesic effects of low doses of racemic ketamine and the morphine derivative oxycodone on postoperative pain after elective tonsillectomy. Also, the suitability of oxycodone for field use was evaluated with respect to ketamine. Plethysmographic pulse-wave amplitude changes were compared with the pain visual analogue scale scores as measures of postoperative pain. The results of this study did not reveal any significant differences between the analgesic potencies of the studied drugs and clearly demonstrate that even suboptimal doses of both ketamine and oxycodone can provide appreciable relief of pain.

Dexmedetomidine premedication attenuates ketamine-induced cardiostimulatory effects and postanesthetic delirium.

BACKGROUND: Dexmedetomidine is a new potent and highly selective alpha 2-adrenoceptor agonist with sedative-hypnotic and anesthetic sparing properties. Because of its sympathoinhibitory activity, it may prove useful in balancing the cardiostimulatory effects and attenuating the adverse central nervous system effects of ketamine. METHODS: A double-blind, randomized and comparative parallel-group study design was employed in 40 volunteers with ASA physical status 1 who were scheduled for elective superficial surgery under ketamine anesthesia. Dexmedetomidine (2.5 micrograms/kg, n = 20) or midazolam (0.07 mg/kg, n = 20) was administered intramuscularly 45 min before induction of anesthesia. Anesthesia was induced with 2 mg/kg ketamine intravenously, and muscle relaxation was achieved with vecuronium. After tracheal intubation, anesthesia was maintained with nitrous oxide/oxygen (2:1) and additional 1 mg/kg intravenous ketamine boluses according to clinical and cardiovascular criteria. Hypotension and bradycardia were treated by increasing the intravenous infusion rate of crystalloids and intravenous atropine, respectively. Sedative and anxiolytic properties, intra- and postoperative drug requirements, psychomotor and cognitive impairments, and cardiovascular effects were compared between the two groups. RESULTS: Dexmedetomidine and midazolam proved to have equal sedative and anxiolytic effects after intramuscular administration, but dexmedetomidine induced significantly less preoperative psychomotor impairment and less anterograde amnesia than did midazolam. Compared to midazolam, dexmedetomidine decreased the need for intraoperative ketamine and was more effective in reducing ketamine-induced adverse central nervous system effects. Dexmedetomidine also was superior to midazolam in attenuating the hemodynamic responses to intubation and the cardiostimulatory effects of ketamine in general, but it increased the incidence of intra- and postoperative bradycardia. CONCLUSIONS: These results suggest that premedication with 2.5 micrograms/kg dexmedetomidine is effective in attenuating the cardiostimulatory and postanesthetic delirium effects of ketamine. However, because of its propensity to cause bradycardia, routine use of an anticholinergic drug should be considered.

Clinician's ability to identify caries risk subjects.

The clinician's ability to identify caries risk children without saliva tests was studied in five health care centers. 77 examiners predicted, after the annual check-up and treatment, whether, during the following 12 months, the child would develop new dentinal caries lesions to be filled. 7917 children aged 5-16 yr were included. Only information routinely available at clinical examinations was used. In general, the overall sensitivity was 44% and specificity 90%. Some clinicians were able to identify the caries risk children with high sensitivity and specificity figures.

Local effects of three standard assault rifle projectiles in live tissue.

A total number of 64 anaesthetized Finnish homebred pigs, weighing 25-30 kg, were wounded in the medial part of one thigh. The shooting range was 30 and 100 m. The weapons were the Finnish M 62, the Russian AKM 47 and the American M 16 A 1, and the projectiles were their standard military ammunition. Simulating typical field conditions the skin of the pigs was covered with a Finnish terrain uniform at 30 m. After trauma the anaesthetized pigs were kept under intensive care for 6 hours before they were debrided on current principles of missile injury operation. The condition of the animals was carefully checked both clinically and in laboratory tests. The pigs showed no signs of shock during the study. The impact and exit velocities were measured, and the respective energies were calculated. At the range of 30 and 100 metres the rate of energy transfer was the same, or 8-9% of the impact energy, with the two 7.62 projectiles. The 5.56 American projectile had a considerably greater energy transfer at the range of 30 m (27.5% of EI) as well as at the range of 100 m (14.4 of EI). With all projectiles the same correlation was observed between debrided tissue per unit length of wound path and rate of energy transfer per unit length of wounds caused by the 5.56 calibre projectile were more injurious than those caused by the 7.62 calibre bullets. The wounds and the tissue damage were estimated by gross appearance, amount of debridement, biopsies and ultrasound studies. The results were comparable with those obtained with soap blocks, except as regards the behaviour of the Russian 7.62 calibre projectile, which was quite different in soap blocks compared to live tissue at both ranges.

Failure of intramuscularly administered lorazepam and scopolamine-morphine premedication to produce amnesic effects to supplement conduction anaesthesia.

Patients undergoing surgery under regional anaesthesia often prefer to be sedated and do not later want to recall the procedure. One hundred and twenty-one patients scheduled for various surgical procedures under epidural, spinal, sacral, or brachial plexus blockades received 1 mg/kg of pethidine, 0.007 mg/kg of scopolamine, plus 0.14 mg/kg of morphine, or 0.03 mg/kg or 0.06 mg/kg or lorazepam intramuscularly as preanaesthetic medication before the operation. The patients's self-assessments of degree of fatigue and apprehension were similar after each premedication when assessed before operation. Postoperative anxiety and confusion as well as need for postoperative care and supervision were greatest after 0.06mg/kg of lorazepam. Significantly (P smaller than 0.05 to P smaller than 0.01) fewer patients given 0.06 mg/kg or lorazepam remembered different events and procedures carried out on them before and after operation than those given other premedications, but no significant differences were noted in patients' ability to recall the performance of operation when asked on the following day. Seventy-seven, 63, and 57% of patients receiving 0.06 mg/kg of lorazepam remembered the start of blockade, performance of operation, and stay in recovery room, respectively. Intravenous sedation should be preferred to these intramuscularly administered premedications if drug-induced amnesia is sought to supplement local anaesthetic techniques.

Untoward effects of ketamine combined with diazepam for supplementing conduction anaesthesia in young and middle-aged adults.

Fifty-six young and 29 middle-aged adults who were scheduled for lower abdominal, anorectal or extremity surgery under epidural, sacral or brachial plexus blockades received intravenous analgesic or anaesthetic doses of ketamine, combined with diazepam, immediately before the start of the operation. Forty-one patients received no supplementary drugs for the conduction anaesthesia and were divided into two groups of controls. On the day following the operation, all the patients were asked about their postanaesthetic reactions and their acceptance of the anaesthetic technique, and the nursing staff expressed their opinion on the amount of work and supervision needed during the post-operative care of the patients. Administration of ketamine 0.5 mg/kg with diazepam 0.15 mg/kg to young or middle-aged patients was not associated with more side-effects or a greater need for post-operative care and supervision than in the control groups. Administration of anaesthetic doses of ketamine 1.5 mg/kg and 3.0 mg/kg with 0.15 mg/kg and 0.3 mg/kg of diazepam, respectively, caused significantly (P less than 0.05) more post-operative anxiety and confusion, as well as a significantly greater need for post-operative care and supervision than in the control patients. It is concluded that, in young or middle-aged patients, supplementing conduction anaesthesia with ketamine 0.5 mg/kg plus diazepam 0.15 mg/kg is not associated with the untoward effects which can be expected after anaesthetic doses of 1.5 mg/kg (or more) of ketamine.

Complete respiratory paralysis caused by a large dose of streptomycin and its treatment with calcium chloride.

Several cases have been reported, in which a rather large dose of streptomycin given intraperitoneally at operation has produced respiratory paralysis. In these cases the treatment has usually consisted of respirator ventilation and administration of atropine and neostigmine. In animal experiments, in which a cessation of breathing has been produced, calcium salts have produced quick recovery. The authors present a case, in which appendicetomy was performed on a 10-year-old girl for a perforated appendix at the end of which, an overdose of intraperitoneal streptomycin was given, followed 10 minutes later by complete cessation of breathing. The patient had to be intubated again and put into a respirator. Neostigmine and atropine were used without noticeable effect. One and a half hours after the breathing had stopped 0.6 g calcium chloride was given intravenously and the girl recovered immediately and completely.