Biomedical subjects

G R Lauretti

Publications and source records attributed to G R Lauretti.

26 records · Page 2Linked to original sources

PubMed1996

Dose-response study of intrathecal morphine versus intrathecal neostigmine, their combination, or placebo for postoperative analgesia in patients undergoing anterior and posterior vaginoplasty.

This study was designed to examine postoperative analgesia with intrathecal neostigmine in a randomized, blinded trial with morphine as the active control in patients undergoing anterior and posterior vaginoplasty. A secondary aim was to provide preliminary data on the interaction between these two drugs. The incidence of adverse effects was also assessed. Forty-eight patients were divided into eight groups (50 micrograms, 100 micrograms, and 200 micrograms morphine [M]; saline; 50 micrograms, 100 micrograms, and 200 micrograms neostigmine [N]; and 50 micrograms morphine + 50 micrograms neostigmine). Anesthesia was provided with a balanced technique. All patients stayed 24 h in the recovery room where adequacy of postoperative analgesia and side effects were assessed. Increasing doses of intrathecal morphine (50 micrograms, 100 micrograms, and 200 micrograms) and intrathecal neostigmine (50 micrograms, 100 micrograms, and 200 micrograms) showed a dose-dependent pattern of analgesia (P < 0.001). The M50 + N50 combination resulted in a better analgesic effect with fewer side effects than M50, N50, and control groups. These preliminary data suggest that spinal neostigmine produces analgesia for vaginoplasty surgery similar in duration to spinal morphine and that the combination of morphine and neostigmine may allow a reduction in the dose of each component for postoperative analgesia.

Adult↗

PubMed1996

Intravenous ketamine or fentanyl prolongs postoperative analgesia after intrathecal neostigmine.

The purpose of this study was to determine whether intravenous (i.v.) ketamine would enhance analgesia from intrathecal (IT) neostigmine compared with combining i.v. fentanyl with IT neostigmine. Sixty patients undergoing vaginoplasty under spinal anesthesia were assigned to one of six groups (n = 10). Patients were premedicated with midazolam plus the i.v. test drug. The IT drugs were 20 mg bupivacaine plus saline or 50 micrograms neostigmine. The control group (CG) received saline i.v. and IT. The neostigmine control group (NCG) received saline i.v. and neostigmine IT. The ketamine group (KG) received ketamine 0.2 mg/kg i.v. and saline IT, and the ketamine neostigmine group (KNG), ketamine i.v. and neostigmine IT. The fentanyl group (FG) received fentanyl 1 microgram/kg i.v. and saline IT, and the fentanyl neostigmine group (FNG), fentanyl i.v. and neostigmine IT. The time to first rescue analgesic was longer for the FNG and KNG compared with the CG, with less rescue analgesic consumption (P < 0.02 and P < 0.01, respectively). Only the FNG had significantly intraoperative nausea/vomiting (P < 0.02). In conclusion, the combination of i.v. ketamine and IT neostigmine results in prolonged postoperative analgesia and less intraoperative nausea and vomiting than the combination of i.v. fentanyl and IT neostigmine.

Analgesia↗

PubMed1994

The activity of opioid analgesics in seizure models utilizing N-methyl-DL-aspartic acid, kainic acid, bicuculline and pentylenetetrazole.

Morphine, fentanyl and pethidine exhibited a biphasic dose response relationship with respect to their effects on seizure thresholds to bicuculline, pentylenetetrazole, N-methyl-DL-aspartate (NMDLA) and kainic acid in mice. The usual pattern was for low doses to be anticonvulsant and higher doses to be proconvulsant. However this pattern was reversed for fentanyl and pethidine when NMDLA was used to induce seizures. The low dose effects of all three opioid drugs was sensitive to 1 mg kg-1 naloxone in all seizure models. The responses to high doses of pethidine were unaffected or enhanced by this dose of naloxone. Naloxone reversed the effects of the higher doses of morphine and fentanyl in all models except bicuculline induced seizures.

Analgesics, Opioid↗

PubMed1991

Modification by drugs used in anaesthesia of CNS stimulation induced in mice by laudanosine and strychnine.

We have investigated in mice the effects of several drugs which may be administered as part of an anaesthetic technique on the convulsive threshold to laudanosine and to strychnine, which is reported to have a similar mechanism of action. I.v. administered propofol, thiopentone and midazolam increased the dose of convulsant necessary to produce seizure when administered 2 min before the convulsive stimulus. In contrast, methohexitone and etomidate exhibited a proconvulsant effect, although with the latter this was significant only in laudanosine-treated mice. Pethidine was proconvulsant in both laudanosine- and strychnine-treated mice, but morphine was proconvulsant only in strychnine-treated mice. The effects of morphine, but not pethidine, were antagonized by naloxone 1 mg kg-1. Laudanosine, but not strychnine caused arousal from anaesthesia in subconvulsive doses. This and other evidence suggests that the mechanism of the CNS excitation produced by strychnine and laudanosine are not the same.

Analgesics↗

PubMedDate not supplied

Tramadol and beta-cyclodextrin piroxicam: effective multimodal balanced analgesia for the intra- and postoperative period.

BACKGROUND AND OBJECTIVES: This study was conducted to evaluate the analgesic efficacy of tramadol, an analgesic with both opioid and nonopioid actions (norepinephrine and serotonin pathways), with beta-cyclodextrin piroxicam, a nonsteroidal antiinflammatory drug, in the perioperative setting. METHODS: The study population consisted of 48 patients scheduled for minor abdominal procedures, who were assigned to one of four groups of 12 patients each. The premedication was either a placebo tablet or a 192.1-mg beta-cyclodextrin piroxicam tablet, administered orally 30-40 minutes before anesthesia induction. After intravenous administration of tramadol 1.5 mg/kg, anesthesia was induced with an intravenous loading dose of propofol. Anesthesia was maintained an intravenous infusion of propofol at 6-12 mg/kg/h plus either saline or tramadol at 1.2 mg/kg/h, atracurium, and a 2:1 nitrous oxide-oxygen mixture. The control group received a placebo tablet and an infusion of saline with propofol for anesthesia maintenance; the tramadol group received a placebo tablet and a continuous tramadol-propofol infusion; the beta-cyclodextrin piroxicam (BCP) group received a BCP tablet and a continuous saline-propofol infusion; and the beta-cyclodextrin piroxicam-tramadol (BCPT) group received beta-cyclodextrin piroxicam and a continuous tramadol-propofol infusion. RESULTS: The relative propofol consumption by the four groups was control = BCP (P > .05) >tramadol (P < .001) > B-CPT (P < .0002). The time for analgesic rescue decreased in the order BCPT > BCP (P < .0002) = tramadol > control (P < .001). The degree of sedation and the visual analog scores 10-cm scale at the time patients requested rescue analgesics were similar among the groups (P > .05). CONCLUSIONS: The combination of tramadol and beta-cyclodextrin piroxicam provided better perioperative analgesia than tramadol alone.

Abdomen↗

PubMedDate not supplied

Postoperative analgesia and antiemetic efficacy after subarachnoid neostigmine in orthopedic surgery.

BACKGROUND AND OBJECTIVES: The efficacy of operatively administered spinal neostigmine to provide analgesia and that of different antiemetics to prevent neostigmine-related nausea and vomiting were evaluated in patients undergoing tibial or ankle reconstruction. METHODS: One hundred patients were randomized to five groups (n = 20). The intravenous antiemetic test drug (except propofol) was given as premedication in the holding room, after intravenous midazolam, 0.05 mg/kg. The subarachnoid drugs administered were 20 mg bupivacaine (0.5%) in conjunction with 100 micrograms neostigmine, except for the saline group (S group), which received bupivacaine and saline. The S group, the neostigmine group (N group), and the propofol group (P group) received saline as the intravenous test drug. The droperidol group (D group) received intravenous droperidol 0.5 mg, and the metoclopramide group (M group) received intravenous metoclopramide 10 mg. The P group had a continuous intravenous propofol infusion (2-4 mg/kg/hr), started 10 minutes after the spinal injection. Nausea, emetic episodes, and the need for analgesic (disclofenac) or antiemetic medication were recorded for the first 24 hours following surgery and scored by a 10-cm visual analog scale (VAS). RESULTS: Subarachnoid neostigmine 100 micrograms did not affect subarachnoid bupivacaine analgesia as measured by time to first rescue analgesic in most patients, but it decreased the overall 24-hour visual analog scale (VAS) scores and the need for postoperative analgesics in 24 hours (P < .001). The incidence of intraoperative nausea and vomiting was higher in the N, D, and M groups than in the S group (P < .001). Following surgery, the 3-hour VAS assessment for emesis was higher for the N, P, and M groups than for the S group (P < .05). The overall 24-hour assessment was similar among groups. CONCLUSIONS: Subarachnoid neostigmine reduced postoperative pain scores and analgesic requirements. Whether it prolonged the duration of action of diclofenac or enhanced the mechanisms involved in spinal analgesia cannot be determined from these data. Although propofol and droperidol appeared to be more effective during and after surgery, respectively, all neostigmine groups were associated with a high consumption of antiemetics.

Adult↗

PubMedDate not supplied

Subarachnoid neostigmine does not affect blood pressure or heart rate during bupivacaine spinal anesthesia.

BACKGROUND AND OBJECTIVES: Intraspinal administration of neostigmine has been shown to prevent induction of hypotension in rats by bupivacaine spinal block, and thus to provide greater hemodynamic stability. This study was undertaken to determine whether subarachnoid neostigmine would prevent bupivacaine spinal anesthesia from causing hypotension or bradycardia in patients undergoing abdominal hysterectomy. METHODS: Of 40 patients scheduled for abdominal hysterectomy under spinal anesthesia, 20 were randomly assigned to each of two groups. The control group (CG) received 1.5 mL subarachnoid saline followed by 15 mg (3 mL) of hyperbaric bupivacaine 0.5%. The neostigmine group (NG) received 75 micrograms (1.5 mL) of subarachnoid neostigmine followed by 15 mg (3 mL) of hyperbaric bupivacaine 0.5%. No preload was given. Hypotension was treated with 4-mg intravenous boluses of ephedrine to keep blood pressure above 75% of the baseline value. The skin body temperature was measured with probes at the suprascapular region and at the foot. RESULTS: Spinal neostigmine (75 micrograms) failed to prevent bupivacaine-induced hypotension. There was no statistical difference in the incidence of brady-cardia between the groups (NG, 2/20; CG 1/20), although the bradycardia appeared to be qualitatively different, being somewhat delayed in the NG. Spinal neostigmine did not alter the onset or duration of sensory block and did not affect skin body temperature in either anesthetized or unanesthetized sites. The incidence of intraoperative nausea was 20% in the NG and 5% in the CG. CONCLUSION: A 75-micrograms subarachnoid neostigmine dose does not affect blood pressure or heart rate during bupivacaine spinal anesthesia.

Adult↗

PubMedDate not supplied

Postoperative analgesia and antiemetic efficacy after intrathecal neostigmine in patients undergoing abdominal hysterectomy during spinal anesthesia.

BACKGROUND AND OBJECTIVES: Postoperative analgesia and antiemetic efficacy after intrathecal neostigmine were investigated in a randomized, double-blind, placebo-controlled trial of 100 patients undergoing abdominal hysterectomy. METHODS: The patients were assigned to one of five groups (n = 20), and received intravenous prior to the spinal block the antiemetic test drug (except propofol) and 0.05 mg/kg midazolam. The control group (group C), the neostigmine group (group N), and the propofol group (group P) received saline as the test drug. The droperidol group (group D) received 0.5 mg intravenous droperidol, and the metoclopramide group (group M) 10 mg intravenous metoclopramide. Group P was single-blinded and had an intravenous continuous propofol infusion (2-4 mg/kg/h) turned on 10 minutes after the spinal injection. The intrathecal drugs administered were 20 mg hyperbaric bupivacaine (0.5%) associated with either 100 microg neostigmine or saline (for group C). Nausea, emetic episodes, and the need for rescue medication were recorded for the first 24 hours postoperative and scored by the Visual Analog Scale (VAS). RESULTS: Time-to-first-rescue medication and rescue medications in 24 hours were similar among the groups (P = .2917 and P = .8780, respectively). Intrathecal 100 microg neostigmine was associated with a high incidence of nausea and vomiting perioperative, leading to a high consumption of antiemetics (P < .002). None of the antiemetic test drugs were effective in preventing nausea and vomiting after 100 microg neostigmine. CONCLUSIONS: Intrathecal neostigmine (100 microg) was ineffective for postoperative analgesia after abdominal hysterectomy due to side effects of nausea and vomiting.

Anesthesia, Spinal↗