Intravenous Dezocine for Postoperative Pain: A Double‐Blind, Placebo‐Controlled Comparison With Morphine

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97255/1/j.1552-4604.1986.tb03523.x.pd

Regional anaesthesia for outpatient surgery

Regional anaesthesia is an ideal anaesthetic technique for many outpatient surgery procedures. With proper preparation, selection and planning, regional anaesthesia will provide excellent operating conditions for the surgeon and a very satisfactory anaesthetic state for the patient in a cost-effective way. Its minimum effect on major organ functions, intense sensory blockade, low potential for postoperative side effects, and its ability to provide postoperative pain control, offers an excellent set up for these patients who will go home soon after the surgery.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/31894/1/0000846.pd

Low dose intravenous infusion technique with ketamine

Low dose ketamine is a relatively new technique. The recommended doses vary considerably. It was therefore decided to establish the minimum dose of ketamine required to produce satisfactory analgesia, sedation and amnesia in 50% of a population of adult volunteers. Twenty adult volunteers aged 20 to 42 years were the subjects of the study. Twenty minutes following intravenous (iv) pre-treatment with 0·3 mg of atropine and 0·2 mg/kg of diazepam each volunteer received a bolus of ketamine 1·0 mg/kg iv followed by ketamine iv infusion at the rate of either0·5 mg/kg/hour(10cases) or 1·0 mg/kg/hour (10 cases). The grade of sedation was determined on a scale of 1–5 and the frequency of amnesia was assessed using visual memory cards. Analgesia was determined by pin prick. Diazepam alone produced no analgesia and only moderate degree of sedation. Ketamine produced satisfactory analgesia to pin prick in both the groups. Ketamine bolus produced marked sedation for about 20 min followed by moderate sedation during iv infusion in both the groups. During the iv infusion of ketamine at arate of 0·5 mg/kg/hour the amnesic effects declined to 20% in 45 minutes, while during infusion of 10 mg/kg/hour the frequency reached a maximum at 50–60%. The minimum dose of ketamine required to produce amnesia in 50% of this population was therefore 1·0 mg/kg/hour after a bolus injection of 1·0 mg/kg given iv.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75725/1/j.1365-2044.1980.tb03882.x.pd

Pneumocephalus after posterior fossa exploration in the sitting position

Entrainment of air following exploration of posterior cranial fossa in the sitting position was studied in five patients. Intracranial pressure was monitored through a ventriculostomy catheter after closure of the dura. In three patients nitrous oxide was added to the breathing mixture only after the baseline intracranial pressure had stabilised following closure of the dura. A marked rise in intracranial pressure was observed immediately. A rapid decrease in intracranial pressure occurred when nitrous oxide administration was stopped. Two patients were given nitrous oxide from the beginning. No change in intracranial pressure was noted. Computerised tomogram on the first postoperative day revealed a significant amount of air in eight cases.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72920/1/j.1365-2044.1982.tb01711.x.pd

Recovery characteristics of three anaesthetic techniques for outpatient orthopaedic surgery

The goals of this study are to observe prospectively the perioperative recovery characteristics associated with general anaesthesia (GA), spinal anaesthesia (SAB), and epidural anaesthesia (EPID) in 200 patients scheduled for outpatient knee arthroscopy. Patients were observed from the time they entered the recovery room until they were discharged. Patients were contacted on postoperative days (POD) 1, 3, and 5. The EPID group had the quickest recovery times (125 +/- 37 min, mean +/- SD, ANOVA P < 0.01) compared with the GA group (165 +/- 57 min) and SAB group (167 +/- 51 min). Comparing the side effects of the three anaesthetic techniques, GA was associated with the highest incidence of nausea (27%) and vomiting (16%) on the day of surgery that persisted into the first postoperative day (nausea 41 % and vomiting 22%). There was no difference in the incidence of headache overall; however, SAB was associated with a 13% incidence of postdural puncture (PDP) headache that became apparent on POD 3. All the PDP headaches resolved with conservative therapy by the first postoperative week, except for two patients who required an epidural blood patch. The EPID group followed by the SAB and GA groups, had the highest incidence of backaches on POD 1 (respectively, 63%, 41% and 17%). By POD 3, the incidence of backache was not statistically different between groups. No specific treatment for backache was required. The ideal anaesthetic has not been developed, but our data suggests that an epidural technique is advantageous for knee arthroscopy in terms of a quick recovery and minimal adverse effects.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30913/1/0000582.pd

Propofol versus thiamylal-enflurane anesthesia for outpatient laparoscopy

Study Objective: To determine whether propofol anesthesia differs from thiamylal-enflurane anesthesia in induction characteristics, intraoperative hemodynamics, post-operative side effects, and postoperative psychomotor function recovery.Design: A randomized, double-blind, two-group study.Setting: A large university hospital with gynecologic outpatient operations performed in an integrated operating room suite.Patients: Sixty adult women (ASA physical status I or II) undergoing an outpatient gynecologic laparoscopic operation with an anesthesia time of approximately 60 minutes.Interventions: No pharmacologic premedication. Pretreatment with intravenous droperidol 0.6 mg and sufentanil 0.2 [mu]g/kg before induction of anesthesia. Anesthesia was induced with either thiamylal 4 mglkg (Group 1) or propofol 2.5 mglkg (Group 2). Anesthesia was maintained with either nitrous oxide (N2O) and enflurane, 2-0.5% inspired concentrations; (Group 1) or with a continuous infusion of propofol 200-100 [mu]g/kg/min and N2O (Group 2).Measurements and Main Results: In psychomotor function tests (Trieger dot test and p-deletion test) administered preoperatively and postoperatively, no difference was found between the groups. No difference was found in induction time, although significantly more patients reported pain after the propofol injection, or in intraoperative hemodynamics (mean arterial pressure and heart rate). Immediate recovery time (emergence from anesthesia) and intermediate recovery time (ambulation, oral intake, and discharge time) were significantly shorter after propofol anesthesia. Fewer postoperative side effects, such as nausea and vomiting, were reported after propofol anesthesia.Conclusions: Induction and maintenance of anesthesia with propofol were comparable to those with thiamylal-enflurane, except patients experienced more pain on injection after propofol. Both immediate and intermediate recovery were more rapid after opofol anesthesia compared with enflurane-based anesthesia.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30070/1/0000440.pd

Enhancement of the leaching rate of uranium in the presence of ultrasound

In the present work, experiments have been performed for leaching (recovery) of uranium from MgF2 (byproduct from the uranium ore recovery process) under various conditions of leach acid concentration with and without the presence of ultrasound, under different energy dissipation rates (different rotational speeds of conventional stirring by impeller), and on different MgF2 particle size distributions. The enhancement of the leaching rate due to ultrasound is found to occur in two steps: (1) MgF2 particle fragmentation leading to high specific solid-liquid interfacial area and by increase in the surface diffusional rate of the reactive species; (2) enhancement in the convective diffusivity of the leach acid solvent through micropores of the MgF2 agglomerate structure due to convective motion created by the cavitation phenomena (shock wave propagation, microjet formation) at the solid-liquid interface. Thus, the overall recovery has been increased by the application of ultrasound with several additional advantages such as low leach acid concentration and decrease in the leaching operation time. The energy dissipation rate with the use of ultrasound was very high, yet, at an equivalent energy dissipation rate in the form of conventional stirring, leaching rates or the final extent of the leaching could not be matched. This indicated that the scale (time and spatial) of energy dissipation has important effect on the overall leaching rate. Kinetics shows that the leaching operation can be explained as a classical shrinking core kinetics phenomenon with pore diffusion resistance as the rate-limiting step

Sono-chemical leaching of uranium

A fundamental study on the mechanism of uranium leaching in nitric acid and sulphuric acid media has been carried out to understand the effect of the ultrasound on leaching. The use of ultrasound clearly improves the leaching rate within the studied leach acid media. The enhancement in the leaching rate in the presence of ultrasound is higher with low leach acid concentration of nitric acid (HNO3), and it is high at high leach acid concentration in the case of sulphuric acid (H2SO4) being used as a leachant, when compared to conventional mechanical agitation. The basic reason behind this observed variation is explained on the basis of the reaction mechanism involving the oxidative conversion of acid insoluble tetravalent uranium form to the soluble hexavalent form of uranium in the presence of ultrasound at a faster rate