PubMed Health⌕ Search

Biomedical subjects

M Tverskoy

Publications and source records attributed to M Tverskoy.

At least 19 recordsLinked to original sources
PubMed2003

Intramuscular administration of lidocaine or bupivacaine alters the effect of midazolam from sedation to hypnosis in a dose-dependent manner.

We examined the sedative/hypnotic interaction between the administration of intravenous (i.v.) midazolam and intramuscular (i.m.) lidocaine or bupivacaine. Women undergoing gynecological surgery (n = 150) were randomly assigned to 15 dose groups of 10 patients each. Fifty patients received one of five predetermined doses of midazolam for the calculation of its median effective dose (ED50). The remaining patients (n = 100) received i.v. midazolam 0.1 mg/kg following an i.m. injection of either bupivacaine, lidocaine, or saline (control). Three minutes after the i.v. dose, the loss of response to verbal command was evaluated. The ED50 of midazolam was 0.226 mg/kg (95% confidence interval [CI] 18-027; p = 0.03). Both bupivacaine and lidocaine enhanced the effect of midazolam in a dose-dependent fashion. The hypnotic ED50 for bupivacaine and lidocaine was 0.7 mg/kg (95% CI 0.5-1.0) and 3.32 mg/kg (95% CI 2.2-11.7), respectively. The slopes of the dose-response curves were significantly different (p < 0.01). Local anesthetics that are well within the range of clinical use for regional blocks or local infiltration can bring the effect of midazolam from the sedative into the hypnotic range.

Adult↗
PubMed2001

Preliminary evaluation of epidural morphine for treatment of heroin withdrawal.

OBJECTIVE: To evaluate the efficacy of epidural morphine in treating heroin withdrawal in patients who failed to detoxify by the other methods. DESIGN: Prospective study. SETTING: Department of Psychiatry of a general hospital. PATIENTS: 8 ASA physical status I patients, aged 26 to 42 years, not having concurrent diseases requiring medication, and who had previously failed other methods of detoxification. INTERVENTIONS: Epidural catheters were inserted at the L(3)-L(4) interspace. Bolus injections of morphine sulfate, 3.0 mg in normal saline, were administered epidurally at 24-hour intervals. Treatment continued for 10 to 12 days. MEASUREMENTS: Withdrawal symptoms, such as mydriasis, insomnia, rhinorrhea, arthralgia, muscular pain, tooth pain, vomiting, diarrhea, dysphoria, and drug craving were monitored. MAIN RESULTS: Withdrawal symptoms ceased within 10 days. Withdrawal symptoms were diminished or entirely abolished by the treatment, and no patient requested to drop out of the program. Discontinuation of the epidural injections did not cause relapse of withdrawal. All patients reported that withdrawal with epidural morphine was considerably easier compared to other methods that they had previously experienced. CONCLUSIONS: A preliminary evaluation of epidural morphine in addicts that failed previous detoxifications showed high effectiveness of this method in reducing withdrawal symptoms.

Adult↗
PubMed1998

The peripheral effect of fentanyl on postoperative pain.

UNLABELLED: The clinical value of the analgesic effect of opioids administered peripherally (except for intraarticular administration) has not been clearly demonstrated. The aim of this study was to test the hypothesis that fentanyl, added to a local anesthetic for wound infiltration, can enhance postoperative analgesia via a peripheral mechanism. Patients with inguinal herniorrhaphy performed under spinal anesthesia were randomly assigned to one of two groups (n = 10 each). At the end of surgery, the wound was infiltrated with 10 mL of lidocaine 0.5% and fentanyl 0.001% (10 microg) in one group; in the other group, the wound was infiltrated with 10 mL of lidocaine 0.5% alone (and fentanyl 10 microg IM contralaterally). The following variables were determined in a double-blind manner: the duration of anesthesia (response to a von Frey filament), the duration of analgesia (time to mild postoperative pain), postoperative meperidine consumption, intensity visual analog scale of spontaneous and movement-associated pain 24 h after surgery, and wound pain threshold 24 h after surgery (pressure algometry). The addition of fentanyl for wound infiltration enhanced the duration of anesthesia (130+/-37 vs 197+/-27 min; P < 0.001) and decreased the intensity of spontaneous (50+/-17 vs 19+/-18 mm; P < 0.002) and movement-associated (56+/-15 vs 26+/-21 mm; P < 0.002) pain 24 h postoperatively. Differences between groups for other variables were not statistically significant. Fentanyl added to a local anesthetic for wound infiltration after spinal anesthesia can enhance postoperative analgesia by a peripheral mechanism. IMPLICATIONS: Fentanyl can enhance analgesia by a peripheral mechanism. Added to a local anesthetic for wound infiltration, it may be of benefit for the relief of postoperative pain.

Adolescent↗
PubMed1997

Hypnotic effect of i.v. propofol is enhanced by i.m. administration of either lignocaine or bupivacaine.

We have compared the hypnotic requirements for i.v. propofol when combined with i.m. lignocaine or bupivacaine. Ninety women (ASA I, II) undergoing minor gynaecological surgery were allocated randomly to one of nine groups of 10 patients to receive propofol combined with i.m. lignocaine, bupivacaine or saline, respectively. Propofol was administered in bolus doses of 0.2 mg kg-1 every 30 s until loss of response to verbal command was achieved. Lignocaine and bupivacaine significantly enhanced the hypnotic effect of propofol in a dose-dependent manner. The maximum doses tested (lignocaine 3.0 mg kg-1 and bupivacaine 1.0 mg kg-1) reduced the hypnotic dose of propofol by 34.4% and 39.6%, respectively. We conclude that if lignocaine or bupivacaine is injected into soft tissue before induction of anaesthesia by propofol, the i.v. dose of the latter should be modified accordingly.

Adult↗
PubMed1997

Hypnotic effect of i.v. thiopentone is enhanced by i.m. administration of either lignocaine or bupivacaine.

We have compared the hypnotic requirements for i.v. thiopentone alone and in combination with i.m. lignocaine or bupivacaine. Ninety women, ASA I-II, undergoing minor gynaecological surgery were allocated randomly to nine groups of 10 patients to receive thiopentone combined with i.m. lignocaine, bupivacaine or saline, respectively. Thiopentone was administered in bolus doses of 0.5 mg kg-1 every 30 s until loss of response to verbal command. Lignocaine and bupivacaine significantly enhanced the hypnotic effect of thiopentone in a dose-dependent manner. The maximum doses tested (lignocaine 3.0 mg kg-1 and bupivacaine 1.0 mg kg-1) reduced the hypnotic dose of thiopentone by 39% and 48%, respectively. We conclude that if lignocaine or bupivacaine are injected into soft tissue before induction of anaesthesia by thiopentone, the i.v. dose of the latter should be modified accordingly.

Adult↗
PubMed1996

Ketamine enhances local anesthetic and analgesic effects of bupivacaine by peripheral mechanism: a study in postoperative patients.

Patients with unilateral (n = 14) and bilateral (n = 4) herniorrhaphy participated in this study. With bilateral herniorrhaphy, at the end of the surgery, the wound was infiltrated with a solution of bupivacaine 0.5% and ketamine 0.3% on one side and a solution of bupivacaine 0.5% only, on the other. With unilateral herniorrhaphy, the patients were randomly assigned to one of two groups (n = 7). One group at the end of the surgery received the infiltration with a solution of bupivacaine 0.5% and ketamine 0.3%, the other group received the infiltration with a solution of bupivacaine 0.5% only. The duration of the local anesthetic (response to a von Frey filament) and postoperative analgesic (time to mild spontaneous pain) effects of the infiltrations, as well as wound pain threshold 24 h after surgery (pressure algometry), were determined. In patient with unilateral herniorrhaphy, the addition of ketamine for wound infiltration enhanced the duration of infiltration anesthesia (206 +/- 76 versus 343 +/- 108 min, P < 0.02) and analgesia (240 +/- 45 versus 420 +/- 151 min, P < 0.03). Similar enhancement of the local anesthetic effect was observed in patients with bilateral herniorrhaphy. The increase in pain threshold to pressure on the wound with the addition of ketamine was evident in bilateral herniorrhaphy patients and also with a combination of bilateral and unilateral results (1.39 +/- 0.40 versus 2.35 +/- 0.92 kg, P < 0.02). In the group of five volunteers, the subcutaneous infiltration with 0.3% ketamine produced a local anesthetic effect lasting only 10-20 min. The results indicate that ketamine acting via a peripheral mechanism can profoundly enhance anesthetic and analgesic actions of a local anesthetic administered for infiltration anesthesia.

Analgesics↗
PubMed1996

Alfentanil dose-response relationships for relief of postoperative pain.

The aim of this study was to characterize within-patient alfentanil dose-response curves for the relief of spontaneous postoperative pain and to test the closeness of relationships 1) between pain intensity and alfentanil analgesic requirements, and 2) between alfentanil requirements for analgesic and nonanalgesic (sedative and miotic) effects. The effects of alfentanil were studied in 23 patients after elective abdominal surgery. During a 40- to 60-min testing session, the patient received two intravenous (i.v.) injections of saline (placebo) and up to six 3-micrograms/kg increments of alfentanil at 5-min intervals. The patient rated the pain intensity with a visual analog scale, and in a subgroup of 15 patients the blinded observer rated patients' sedation and measured pupil diameter. Spontaneous postoperative pain was completely relieved in all patients with cumulative doses of alfentanil ranging from 6 to 8 micrograms/kg. The within-patient alfentanil dose-analgesic response curves were primarily quantal in nature: a precipitous decrease in pain intensity (representing > or = 2/3 of the total effect) after the injection of only one of the increments of alfentanil was observed in 15 of 23 patients. When the analgesic effect of alfentanil was presented as the collective response of a group of individuals, the quantal nature of the response was concealed by the wide interindividual variability of the response. No statistically significant relationship was noted between predrug pain intensity and the cumulative dose of alfentanil necessary to produce pain relief. A strong correlation was found between interpatient variabilities in the analgesic and sedative effects of alfentanil (r = 0.75, P < 0.002). At the same time, the relationship between alfentanil requirements for pain relief and that for pupil constriction did not demonstrate any significant correlation. The results suggest that, in a population of patients with postoperative pain, the intensity of spontaneous pain cannot be the primary factor determining the dose of alfentanil necessary for its relief.

Abdomen↗
PubMed1996

Effect of bupivacaine-induced spinal block on the hypnotic requirement of propofol.

The hypnotic dose-response of propofol was compared with its combination with either bupivacaine-induced spinal block or intramuscular bupivacaine 12.5 mg in 105 men, divided into three groups of 35, undergoing lower abdominal, pelvic or lower limb surgery. Dose-response curves were determined for each group using bootstrap analysis. Bupivacaine-induced spinal block at the level of T8-T9 was found to reduce the ED50 of propofol by 39%. While this enhancement of hypnotic effect by spinal block is mostly attributable to reduced afferent input, differences in its potency between drugs suggest a role for additional factors.

Adult↗
PubMed1994

Preemptive effect of fentanyl and ketamine on postoperative pain and wound hyperalgesia.

The aim of this study was to test the hypothesis that the induction and maintenance of anesthesia with the use of fentanyl or ketamine reduces postoperative pain and wound hyperalgesia beyond the period when these effects can be explained by the direct analgesic action of these drugs. Twenty-seven patients scheduled for elective hysterectomy were investigated in a double-blind, randomized study. Patients were divided into three groups. In the fentanyl group, anesthesia was induced with fentanyl 5 micrograms/kg combined with thiopental 3 mg/kg and maintained with isoflurane and fentanyl 0.02 microgram.kg-1.min-1. In the ketamine group, anesthesia was induced with ketamine 2 mg/kg in combination with thiopental 3 mg/kg and maintained with isoflurane and ketamine 20 micrograms.kg-1.min-1. In the control group, anesthesia was induced with thiopental 5 mg/kg and maintained with isoflurane only. Patients in all three groups received identical postoperative pain treatment. The intensity of spontaneous incisional pain and movement-associated pain was measured with a visual analog self-rating method. The surgical wound hyperalgesia was assessed by measuring pain threshold to pressure on the wound by using an algometer, and also by measuring the intensity of pain to suprathreshold pressure on the wound with the visual analog self-rating method. Forty-eight hours after surgery, the pain threshold was 0.90 +/- 0.06 kg in controls, 1.69 +/- 0.19 kg (P < 0.001) in the fentanyl group, and 1.49 +/- 0.15 kg (P < 0.01) in the ketamine group.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Propofol and fentanyl act additively for induction of anaesthesia.

The induction dose-response of propofol was compared with the dose-response of its combination with fentanyl and with that of fentanyl alone in three groups of 60 women undergoing minor gynaecological surgery. Dose-response curves were determined for each group using bootstrap and isobolographic analyses. Propofol was found to act additively with fentanyl for induction of anaesthesia. Twenty-three percent of the ED50 of fentanyl was required in combination with 75% of the ED50 for propofol to achieve the ED50 of the combination. This indicates that, for induction of anaesthesia, propofol and fentanyl are not synergistic.

Adult↗
PubMed1990

Midazolam acts synergistically with fentanyl for induction of anaesthesia.

The induction dose-response of midazolam was compared with the dose-response of its combination with fentanyl and with that of fentanyl alone in three groups of 60 unpremedicated, ASA physical status I or II women undergoing minor gynaecological surgery. The end-point of induction of anaesthesia was inability to open eyes upon command. Dose-response curves were determined for each group with a probit procedure and compared with an isobolographic analysis. Midazolam was found to act in synergism with fentanyl for induction of anaesthesia. Twenty-five percent of the ED50 of fentanyl was required in combination with 23% of the ED50 for midazolam to achieve the ED50 of the combination. This degree of synergism may explain mutual potentiation between opioids and benzodiazepines reported previously.

Adult↗
PubMed1990

Postoperative pain after inguinal herniorrhaphy with different types of anesthesia.

In a randomized, double-blind study, postoperative pain was assessed in 36 patients undergoing inguinal herniorrhaphy with three types of anesthesia: general (thiopental-nitrous oxide-halothane); general with the addition of local (infiltration of the abdominal wall with 0.25% bupivacaine along the line of the proposed incision); and spinal (0.5% bupivacaine). The severity of constant incisional pain, movement-associated incisional pain, and pain upon pressure applied to the surgical wound using an algometer was assessed with a visual analogue self-rating method at 24 h, 48 h, and 10 days after surgery. The addition of local anesthesia significantly decreased the intensity of all types of postoperative pain. This effect was especially evident with constant incisional pain that disappeared almost completely 24 h after surgery. With pain caused by pressure on the site of the surgical incision, the pain score difference between general and general plus local anesthesia was obvious even 10 days after the surgery (with 0.4-kg/cm2 pressure, the pain scores were 16 +/- 3 vs 2 +/- 1, P less than 0.01). The difference in postoperative pain scores between spinal and general anesthesia groups indicated that spinal anesthesia also decreases the pain intensity. However, this decrease is less pronounced than that seen with the addition of local anesthesia: movement-associated pain scores 24 h after surgery were 72 +/- 5 in the general anesthesia group, 40 +/- 6 in the spinal anesthesia group, and 16 +/- 3 in the general plus local anesthesia group (with P less than 0.002 between the groups).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

A rabbit model for evaluation of spinal anesthesia: chronic cannulation of the subarachnoid space.

A rabbit model for evaluation of spinal anesthesia is presented. Chronic cannulation of the subarachnoid space was performed in 44 rabbits using the translumbar approach. An autopsy was performed 24 h after the operation on four of the animals. Intrathecal injections of methylene blue did not reveal any leakage from the spinal space. X-ray examination performed on the second and 30th days after the implantation indicated free spread of the injected solution in the subarachnoid space without any obstruction. Repeated injections of four identical doses of bupivacaine at 3-day intervals showed reproducible pharmacologic effects. Administration of different doses of the anesthetic produced a clear dose-response relationship. The relative activity of the anesthetic agents was found to be identical to that previously obtained in humans. No significant complications after the implantation have been recorded. We suggest the current model as an additional appropriate tool for the investigation of spinal anesthesia.

Anesthesia, Spinal↗
PubMed1989

Midazolam acts synergistically with methohexitone for induction of anaesthesia.

The induction dose-response of midazolam was compared with the dose-response of its combination with methohexitone sodium and with that of methohexitone alone. Three groups of 60 unpremedicated ASA physical state I or II women undergoing minor gynaecological interventions were studied. The end-point of induction of anaesthesia was inability to open eyes upon command. Dose-response curves were determined for each group with a probit procedure and compared with an isobolographic analysis. Midazolam was found to act in synergism with methohexitone for induction of anaesthesia. Twenty-seven percent ED50 for methohexitone was required in combination with 33% of ED50 for midazolam to achieve the ED50 of the combination. This degree of synergism is in agreement with that described in animal research.

Adult↗
PubMed1989

Midazolam-morphine sedative interaction in patients.

The sedative effects of midazolam, morphine, and their combination were studied in ASA physical status I and II patients. The visual analog method was used to determine sedative effect. A self-rated score of 50 mm or more on a 100-mm line was regarded as a positive response to the treatment. The dose-response curves for midazolam, morphine, and their combination (each in a group of 30 patients) were determined by probit procedure and compared with isobolographic and algebraic (fractional) analyses. Interactions between midazolam and morphine when used to produce sedation represent summation, not synergism.

Adult↗