Efficacy and safety of nitrous oxide in alleviating pain and anxiety during painful procedures.

AIMS: To evaluate the efficacy and safety of nitrous oxide for children undergoing painful procedures. METHODS: Ninety children requiring repeated painful procedures (lumbar puncture, bone marrow aspirate, venous cannulation, or dressing changes) were given nitrous oxide at a variable concentration of 50-70%. Procedure related distress was evaluated using the Observational Scale of Behavioral Distress-Revised (OSBD-R). OSBD-R scores were obtained for each of the following phases of the procedure: phase 1a, waiting period; phase lb, during induction with nitrous oxide; phase 2, during positioning and cleaning of the skin; phase 3, during the painful procedure; and phase 4, immediately following the procedure and withdrawal of nitrous oxide. Side effects were monitored and recorded by a second observer. RESULTS: OSBD scores reached a maximum during the induction phase with lower scores during subsequent phases. Children over the age of 6 showed a lower level of distress during nitrous oxide administration and the painful procedure. Eighty six per cent of patients had no side effects. The incidence of vomiting, excitement, and dysphoria was 7.8%, 4.4%, and 2% respectively. Eight patients developed oxygen desaturation (SaO(2) < 95%), but none developed hypoxia, airway obstruction, or aspiration. Ninety three per cent of patients fulfilled the criteria for conscious sedation, and 65% had no recollection of the procedure. Mean recovery time was three minutes. CONCLUSIONS: Inhalation of nitrous oxide is effective in alleviating distress during painful procedures, with minimal side effects and short recovery time.

Perioperative pharmacodynamics of acetaminophen analgesia in children.

BACKGROUND: There are no adequate pharmacodynamic data relating concentrations of acetaminophen in serum to analgesia. METHODS: Children undergoing outpatient tonsillectomy were administered acetaminophen either orally, 0.5-1.0 h preoperatively (n = 20), or per rectum at induction of anesthesia (n = 100). No other analgesic agents were administered. Individual concentrations of acetaminophen in serum and pain scores (0-10) measured over a 4-h postoperative period were analyzed using a nonlinear mixed-effects model (NONMEM). RESULTS: Mean (% CV) estimates of population pharmacokinetic parameters with percent coefficient of variation, standardized to a 70-kg person, for a one-compartment model with first-order input, lag time, and first order-elimination were a volume of distribution of 60 (21) 1 and a clearance of 13.5 (46) 1/h. Rectally administered acetaminophen had an absorption half-life of 35 (63) min with a lag time of 40 min. The absorption half-life for the oral preparation was 4.5 (63) min without a detectable lag time. The relative bioavailability of the rectal compared with the oral formulation was 0.54. The equilibration half-time of an effect compartment was 1.6 (131) h. Pharmacodynamic population parameter estimates (percent coefficient of variation) for a fractional sigmoidal Emax model, in which the greatest possible pain relief equates to an Emax of 1, were Emax = 1, EC50 (the concentration producing 50% of Emax) = 3.4 (94) mg/l, and Hill coefficient = 0.54 (42). CONCLUSIONS: The pharmacodynamics of acetaminophen can be described using a sigmoidal Emax model with a low Hill coefficient. To achieve a mean posttonsillectomy pain score of 3.6 of 10, an effect compartment concentration of 10 mg/l is necessary.

Nurse-controlled analgesia using a patient-controlled analgesia device: an alternative strategy in the management of severe cancer pain in children.

Nurse-controlled analgesia (NCA) using a patient-controlled analgesia (PCA) device has been described for intensive care and postoperative use. This report describes the effective use of this technique for severe episodic and procedural pain in four children with advanced malignancy and high opioid requirements where conventional parenteral analgesia had been inadequate. Both morphine and fentanyl were used. Average duration of NCA was 6.75 days (range 4-12).

Alleged sexual violation of a human female by a Rottweiler dog.

An unusual case involving the alleged sexual violation of a woman by three men and a Rottweiler dog is described. Forensic examination proved difficult and showed little of evidentiary value but did reveal the presence of dog hairs at the scene, and semen from one of the men on the victim's panties. All attempts to locate and identify dog semen were unsuccessful. It was not clear whether dog semen could not be located using available techniques for semen identification, or whether dog semen was, in fact, not present at all.