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Biomedical subjects

N Rawal

Publications and source records attributed to N Rawal.

At least 91 records · Page 5Linked to original sources

Behavioral and histopathologic effects following intrathecal administration of butorphanol, sufentanil, and nalbuphine in sheep.

A large number of opioids and nonopioids have been administered epidurally and intrathecally in the hope of providing segmental analgesia without serious adverse effects. However, neurotoxicity data are generally unavailable for many of these drugs. The present study evaluated the behavioral, motor, electroencephalographic, and histopathologic changes following intrathecal injection of large and small doses of butorphanol, sufentanil, and nalbuphine in sheep. Thirty-two sheep (20-32 kg) were anesthetized and catheters placed intrathecally after hemilaminectomy. The large doses of butorphanol, sufentanil and nalbuphine were 0.375 mg/kg (4.4-5.2 ml), 7.5 micrograms/kg (3.6-4.8 ml) and 0.75 mg/kg (1.5-2.4 ml), and the small doses were 0.075 mg/kg (0.9-1.1 ml), 1.5 micrograms/kg (0.7-0.9 ml) and 0.15 mg/kg (0.38-0.5 ml), respectively. The opioids were administered intrathecally every 6 h for 3 days and the above-mentioned parameters studied. Five sheep received intrathecal saline (1.1 or 5.2 ml) and served as controls. Histopathologic changes were evaluated by a neuropathologist blinded to the study protocol. Irrespective of dose, intrathecal injection of butorphanol was associated with severe behavioral responses such as agitation, rigidity, vocalization, and restlessness, as well as prolonged or irreversible hindlimb paralysis. Electroencephalography showed increased cortical activity or seizure activity. One sheep died because of severe respiratory depression that did not respond to naloxone. Spinal cord histologic changes consisted of suppurative meningitis and myelitis as well as neuronal changes such as spongiosis and chromatolysis. Large doses of intrathecal sufentanil were associated with similar though somewhat less severe responses. The behavioral and motor changes following the small dose of intrathecal sufentanil were of mild to moderate nature. Following intrathecal nalbuphine, the above-mentioned changes were similar to those seen in control animals. We conclude that butorphanol in doses of 0.075 and 0.375 mg/kg intrathecally and sufentanil 7.5 micrograms/kg intrathecally are neurotoxic in sheep.

Animals↗

Induction of anesthesia in children following administration of methohexital into the sigmoid colon.

The authors evaluated the sigmoidal administration of methohexital, the effect of methohexital concentration (1% versus 2%), the effect of dosage (25 mg/kg versus 15 mg/kg) on sleep-success rate, administration - sleep time, recovery time and the effect of aspirating the residual methohexital on recovery time. The study demonstrated that both 1% solution and 25 mg/kg of sigmoidal methohexital were independently associated with significantly higher sleep success rate and faster onset of sleep compared with 2% and 15 mg/kg of sigmoidal methohexital solution respectively. The recovery time was significantly affected by the dose of methohexital and was not significantly affected by the concentration of methohexital solution. Aspiration of the residual methohexital did not significantly affect the recovery time.

Catheterization↗

Influence of perioperative nalbuphine and fentanyl on postoperative respiration and analgesia.

In a double-blind study the relative postoperative respiratory and analgesic effects of perioperatively administered nalbuphine and fentanyl were compared in 60 females undergoing gynecological surgery under i.v. anesthesia. One milliliter (10 mg) nalbuphine was considered equipotent to 1 ml (100 micrograms) fentanyl. In the recovery period pain was assessed by visual analog score (VAS) and recovery by Pegboard scoring. Respiratory function was evaluated by continuous monitoring of respiratory frequency and end-tidal CO2 (ETCO2) and by frequent arterial blood gas analyses. The total volume of analgesic required for surgical analgesia was similar in the two groups. Patients in the nalbuphine group showed mild to moderate increases in pulse rate during the intubation phase and in blood pressure during surgery. Fentanyl was more effective in suppressing these cardiovascular responses. Within the first 15 min following recovery, increasing PaCO2 and ETCO2 as well as respiratory rates below 10/min were noted in 8 patients, who all belonged to the fentanyl group; in 4 of these patients i.v. naloxone had to be administered to reverse respiratory depression. Prolonged sedation was a common feature in patients receiving nalbuphine. It was concluded that fentanyl was superior to nalbuphine in attenuating the pressor responses to intubation and surgery. However, fentanyl was associated with respiratory depression in a considerable number of patients. The quality and duration of postoperative analgesia were similar in the two groups.

Adolescent↗

The effects of oral transmucosal fentanyl citrate premedication on preoperative behavioral responses and gastric volume and acidity in children.

The authors compared the safety, efficacy, and effects on gastric volume and pH of oral transmucosal fentanyl citrate (OTFC) premedication and of placebo lollipop and no premedication in 55 children undergoing elective operations. The patients were randomly assigned to receive no premedication (group A, N = 18); OTFC containing 15-20 micrograms/kg of fentanyl citrate (group B, N = 18); or a placebo lollipop (group C, N = 19). Activity (sedation) and anxiety scores, vital signs (including systolic and diastolic arterial blood pressures, heart and respiratory rates), and pulse oximetry determined oxygen saturation were measured before and at 10-min intervals after premedication until the patients were taken to the operating room. Gastric contents were aspirated via an orogastric tube and analyzed for volume and pH after induction of anesthesia. Quality of induction and recovery were evaluated using scoring schedules; recovery times were measured and side effects recorded. OTFC was readily accepted and provided levels of sedation and anxiolysis significantly greater after 10 min than after no premedication or the placebo lollipop. Arterial blood pressures, heart rate, and oxygen saturations were not different among the three groups. In patients given OTFC, respiratory rates were significantly lower after 10 min than they were in patients having no premedication.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗

Epidural versus combined spinal epidural block for cesarean section.

In a controlled study a single segment combined spinal epidural (CSE) block was compared with epidural block for cesarean section. Thirty healthy parturients were randomly divided into two groups. In both groups a T4 block was aimed at. Bupivacaine was used to provide analgesia in both groups. All patients receiving CSE block had good to excellent analgesia, while 11 patients (74%) receiving epidural block had similar pain relief. This was reflected in the requirement for additional analgesics, sedatives or N2O anesthesia. The muscular relaxation was also better following CSE block. The total dose of bupivacaine for a T4 block was three times larger in patients receiving only epidural block. The maternal and fetal blood bupivacaine levels were correspondingly about three times higher in the epidural group. Additionally, the incidence of maternal hypotension was higher in patients receiving epidural block. Apgar scores, blood gases and neurobehavioural evaluation did not show any differences between the two groups of neonates. No postspinal headache was noted. CSE block appears to combine the reliability of spinal block and the flexibility of epidural block while minimizing their drawbacks.

Adult↗

Clinical experience of long-term treatment with epidural and intrathecal opioids--a nationwide survey.

Long-term use of spinal opioids to treat chronic severe pain is widely established. However, the indications, shortcomings and complications of the method have not been completely described. Experience with spinal opioids was analysed for the period 1979-1984 in a nationwide Swedish survey. Out of 93 anaesthesia departments, 69 used the method. Approximately 750 patients were treated with epidural morphine for an average duration of 124 days (3-450). Eighteen patients were treated with intrathecal morphine for an average period for 47 days (3-90). The intrathecal approach was used in all clinics because of failure of the epidural route. In only one department was the intrathecal approach used as the primary route of therapy, depending on the mechanism of pain. The highest daily morphine dose was 480 mg and 50 mg for epidural and intrathecal routes, respectively. The patients given the highest dosages were not necessarily those subjected to the longest treatment. The need for increased dosage seems to be related not only to changes in receptor sensitivity but also to changes in pain mechanisms. No case of threatening ventilatory depression was reported. Thirty-two departments had treated a few patients with chronic non-cancer pain conditions. Initial results were considered "excellent" in 11 departments, but at follow-up results were excellent in only one department. In addition to dislocation, occlusion of the catheters or leakage, injection pain was an obstacle to successful treatment. Pruritus urinary retention, and local infections were not reported as significant problems, but one case of meningitis was reported.

Anesthesia Department, Hospital↗

Combined intrathecal morphine and bupivacaine for cesarean section.

The effects of adding 0.2 mg preservative-free morphine sulfate in 0.2 ml solution to hyperbaric spinal bupivacaine were evaluated in a double-blind randomized prospective study of 34 patients undergoing elective repeat cesarean section. In the control patients (n = 17), 0.2 ml saline instead of morphine was added to bupivacaine. The intrathecal morphine significantly improved intra- and postoperative analgesia, e.g., 82% of patients given morphine compared with 41% of the control patients did not require analgesic supplementation to the spinal anesthesia during surgery; postoperatively, the former patients did not request additional analgesia for 27 +/- 0.7 hours (mean +/- SEM) compared with 2 +/- 0.3 hours in the control patients. Neonatal condition was not adversely affected by this small dose of morphine administered 11 +/- 1 minutes before delivery. Combining 0.2 mg morphine with hyperbaric spinal bupivacaine for cesarean section is a safe and effective method of improving intraoperative pain relief and providing adequate prolonged postoperative analgesia.

Analgesia↗

Present state of extradural and intrathecal opioid analgesia in Sweden. A nationwide follow-up survey.

A nationwide follow-up survey was undertaken to study the use of extradural and intrathecal opioids in the management of pain, to estimate the incidence of delayed ventilatory depression and to study post-injection surveillance routines. A questionnaire was sent to all 93 anaesthetic departments in Sweden; 96% responded. The major indication for using extradural opioids was the treatment of postoperative, traumatic and cancer pain. During 1984 over 14,000 patients received extradural, and over 1100 patients intrathecal, opioids. Morphine was the predominant opioid for extradural administration and was used in 96% of patients. Extradural opioid analgesia constitutes about 25% of all extradural blocks performed in Sweden. Pruritus and urinary retention were considered as minor problems; however, the risk was considerably higher after intrathecal morphine. The incidence of delayed ventilatory depression was about 1:1100 (0.09%) following extradural morphine and 1:275 (0.36%) following intrathecal morphine. Risk factors for delayed ventilatory depression are discussed. Administration of extradural morphine for postoperative pain relief in patients undergoing major surgery is considered a high benefit-low risk technique by most Swedish anaesthetists. The results of the present nationwide survey suggests that, following extradural morphine, surveillance of patients for more than 12 h appears unnecessary.

Adult↗

Influence of naloxone infusion on analgesia and respiratory depression following epidural morphine.

The influence of two different concentrations of iv naloxone infusion on the analgesia and adverse effects of epidural morphine were compared in a double-blind, placebo-controlled study. Forty-five patients undergoing gallbladder surgery were provided postoperative analgesia by 4 mg epidural morphine; they then received an iv infusion over a 12-h period consisting of either 5 micrograms X kg-1 X h-1 naloxone, 10 micrograms X kg-1 X h-1 naloxone, or saline. Pain relief was assessed by hourly visual analog scoring (VAS) and by direct questioning of the patient. Requirement of additional analgesia was noted. Respiratory frequency was monitored every 15 min and arterial blood gases were analyzed every 2 h for 24 h. Peak expiratory flow (PEF) was recorded 6 and 24 h postoperatively. Steady-state kinetics of naloxone were determined by a modified radioimmunoassay (RIA) method. All patients had good to excellent postoperative pain relief. Naloxone, 5 micrograms X kg-1 X h-1, did not appear to have any effect on epidural morphine analgesia. However, naloxone infusion at the rate of 10 micrograms X kg-1 X h-1 reduced the duration of analgesia by about 25%, and more frequent injections of epidural morphine were required to give effective analgesia. Complete reversal of analgesia was not seen in any patient. A dose-related stimulatory effect on respiratory frequency was noted in the groups receiving naloxone. PaCO2 values also were better in these groups as compared to values in the placebo group.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Laboratory assessment of three new monitors of blood glucose: Accu-Chek II, Glucometer II, and Glucoscan 2000.

We describe a laboratory assessment of three new monitors of blood glucose concentrations: the Boehringer "Accu-Chek II" (B), the Ames "Glucometer II" (A), and the Lifescan "Glucoscan 2000" (L). Inherent imprecision (CV) of each monitor was less than 2%. Maximum difference between individual monitors of the same type was less than or equal to 0.5 mmol/L. The volume of blood applied to the test strips is not critical, but duration of blood incubation or color development should be precise. Two types of test strips retained sufficient color 48 h after development to allow checking of the original measurement, and would be suitable as quality-control "spot" checks. Correlation coefficients for results for whole-blood glucose vs those for serum glucose (measured with the Beckman ASTRA-8) were: 0.992 (B), 0.967 (A), and 0.988 (L). Bias plots of these data showed positive bias for A (0.45 mmol/L) and L (0.17 mmol/L) in relation to serum-glucose measurements, but a negative bias of 0.32 mmol/L for B. Calibration solutions are not interchangeable. Although these versions of the monitors are probably not analytically superior to earlier models, they are easier to use.

Blood Glucose↗