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Biomedical subjects

F Magora

Publications and source records attributed to F Magora.

At least 37 records · Page 2Linked to original sources

Plasma concentrations of methadone during postoperative patient-controlled extradural analgesia.

Plasma concentrations of methadone were measured by gas chromatography in 16 patients receiving extradural methadone by continuous infusion for relief of postoperative pain. Venous blood samples were taken after a loading dose of extradural methadone 2 mg and during infusion of 0.46 mg h-1 plus patient-controlled increments of 0.2-1 mg. Mean (SD) plasma concentration of methadone was 9.8 (2.1) ng ml-1 at 15 min; this did not change significantly during the first 2 h, after which it increased gradually to 32.2 (4.6) ng ml-1 (P less than 0.001) at the end of 24 h. The mean quantity of extradural methadone required to produce effective analgesia was 10.3 (1.8) mg during the first 12 h after operation and 6 (1.0) mg for the subsequent 12 h. The mean amount of methadone for effective analgesia on the second day was 7.6 (1.1) mg. No adverse effects were detected during the 2-3 days of methadone therapy. Plasma concentration of methadone increased significantly during patient-controlled infusion of extradural methadone in the first 24 h after operation, suggesting rapid vascular uptake. Systemic activity of the drug contributes to the analgesic effect of extradural methadone.

Adult↗

[Continuous intercostal nerve block for chronic pain].

21 ambulatory patients with acute or chronic pain localized to the chest, were treated successfully by continuous intercostal block. They included 6 women and 15 men, aged 39-70. Treatment was initiated in the outpatient clinic and continued at home for usually 5-6 days. Between 15-20 ml of 0.5% marcaine were continuously injected over the course of 6-12 hours through a catheter introduced into the intercostal space by a Touhy needle. 76% of the patients had substantial relief of pain during the block and required only minimal systemic medication. During a 3 month follow-up after cessation of the block, up to 65% were still pain-free. Results were poor or only fair in those with malignancy and long-standing intercostal neuralgias. There were no serious side-effects during treatment. This method is an important new tool in the treatment of pain.

Acute Disease↗

[Intrapleural marcaine for postoperative analgesia].

Intrapleural marcaine has been described as an effective method of analgesia following upper abdominal and thoracic operations and is no longer regarded as experimental. We have shown that the same quality of analgesia can be achieved by injecting the drug through a catheter inserted intraoperatively through the surgical incision. In our method, applied in 9 cases, there is no risk of pneumothorax as a result of piercing the chest wall, since intraoperative placement of the intrapleural catheter is very easy. We therefore suggest it as the method of choice for postoperative analgesia in kidney operations. It is especially recommended in elderly patients with chronic pulmonary disease who do not tolerate narcotics well.

Bupivacaine↗

Urodynamic studies after intrathecal administration of baclofen and morphine in dogs.

The effects of intrathecally administered baclofen and morphine on the lower urinary tract dynamics of anesthetized dogs were investigated by means of cystometrogram and urethral pressure profile measurement. The experiments were performed prior to and 30, 60 and 90 minutes following intrathecal injection of either baclofen (0.03 mg./kg.), morphine (0.03 mg./kg.), or a mixture of the two (0.03 mg./kg. of each drug). Vesical pressure was significantly depressed after either baclofen (p less than 0.005) or morphine (p less than 0.005), while urethral pressure was decreased significantly only following baclofen (p less than 0.025). Administration of a baclofen/morphine admixture resulted in an additive reaction on the urethral pressure profile, compared with the changes brought about by each drug alone. Relaxation of the bladder and reduction in urethral resistance occurred 30 minutes post injection, increasing progressively after 60 and 90 minutes. The results demonstrated that baclofen, by its influence on cord neuron interaction, is capable of inhibiting the activity of the smooth muscle of the normal bladder and urethra, which in the case of the latter became more pronounced when both drugs were administered simultaneously by the intrathecal route.

Animals↗

Extradural bupivacaine and methadone for extracorporeal shock-wave lithotripsy.

Combined extradural bupivacaine and methadone analgesia was investigated in 144 patients who underwent extracorporeal shock wave lithotripsy (ESWL). Patients were assigned randomly to one of three groups: group I--extradural 0.5% bupivacaine hydrochloride 0.75 mg kg-1; group II--extradural 0.1% methadone hydrochloride 4 mg after the bupivacaine; group III--as group II, plus a continuous extradural infusion of methadone 0.3 mg h-1 after operation. In all patients, only partial motor deficit occurred. During ESWL, patients who received extradural bupivacaine and methadone had significantly less pain compared with those who had bupivacaine alone (P less than 0.025). Extradural anaesthesia and immersion in the warm water bath were accompanied by only mild fluctuations in arterial pressure. After ESWL, significantly more patients with continuous methadone infusion were pain free (P less than 0.05) and they required less systemic analgesics. The anaesthesia during and after the ESWL procedure may be carried out safely and effectively by the administration of small doses of bupivacaine combined with methadone followed by infusion of the opioid.

Analgesia, Epidural↗

Urodynamic studies after intrathecal fentanyl and buprenorphine in the dog.

Cystometrograms (CMG) and urethral pressure profiles (UPP) were used in six anesthetized dogs to study the urodynamic effects of intrathecal (IT) injections of fentanyl and buprenorphine. The CMG and UPP were examined for each of the two drugs in all dogs (four experiments per animal). The measurements were performed before and 15, 30, 60, 90, and 120 min after IT injection of either 1.5 micrograms/kg fentanyl or 2 micrograms/kg buprenorphine. Fifteen minutes after IT injection of fentanyl, reduction in bladder tone was already noted, followed by decreases in mean peak vesical pressure of 48.3% +/- 6.0 (SE) (P less than 0.05) and mean peak urethral pressure of 38% +/- 3.0 (P less than 0.05) between 30 and 60 min after injection. These decreases, occurring in each experiment, gradually lessened at 90 and 120 min. The effects of IT buprenorphine, a partial opioid agonist, on bladder and urethral dynamics were inconsistent and non-significant in all studies. Disturbances of micturition observed clinically after spinal opioid administration may be related to the decrease in intravesical pressure and the resulting highly compliant bladder. Relaxation of the urethral musculature seen 15 min after IT fentanyl may prevent overdistension of the bladder and its associated complications.

Animals↗

Physostigmine and naloxone reverse the effect of intrathecal morphine on the canine urinary bladder.

Cystometrograms and urethral pressure profiles were used in 11 anaesthetized dogs to study the urodynamic effects of intravenously administered physostigmine (Group I--seven dogs) and intravenously administered naloxone (Group II--four dogs) following intrathecal morphine. In four of these dogs (Group III) intravenous physostigmine preceded the intrathecal morphine injection. In Groups I and II, intrathecal morphine 0.03 mg kg-1 caused a significant relaxation of the detrusor P less than 0.05), as expressed by a fall of 34.2 +/- 4.4% (SE) in mean intravesical pressure and a rise of 57 +/- 12.7% (SE) in calculated detrusor compliance at 90 min. Both physostigmine, 0.1 mg kg,-1 and naloxone, 0.025 mg kg,-1 given at this time completely abolished the influence of the narcotic on the bladder without changing urethral pressures. In Group III, physostigmine produced a marked rise in intravesical pressure (P less than 0.01) that was reversed by subsequent morphine. It is of interest that physostigmine, a potent cholinergic agent, and naloxone, a pure opiate antagonist, exert a similar action on bladder function.

Animals↗

Application of a new method for measurement of plasma methadone levels to the use of epidural methadone for relief of postoperative pain.

A method is described for measurement of plasma methadone concentrations using a gas chromatic technique that is rapid and specific and enables the detection of concentrations of less than 1 ng/ml in plasma samples of only 1 ml. The method, when used to determine the plasma methadone levels in patients given continuous epidural infusions of methadone plus on-demand supplementation for relief of postoperative pain, showed plasma methadone plateaus of around 10 ng/ml (starting at 15 min and lasting over 2 hr) and 20 ng/ml (starting at 3 hr and lasting over the period of treatment) (P less than 0.001) after an initial 2-mg methadone epidural bolus and with continuous epidural methadone. Mean plasma methadone levels of around 10 ng/ml were associated with pain relief. Analgesia could be safely maintained for 24 hr.

Adult↗