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Biomedical subjects

A Borgeat

Publications and source records attributed to A Borgeat.

At least 37 records · Page 2Linked to original sources
PubMed2001

Acute and nonacute complications associated with interscalene block and shoulder surgery: a prospective study.

BACKGROUND: The incidence, etiology, and evolution of complications after interscalene brachial plexus block (ISB) are not well-known. The authors prospectively monitored 521 patients for complications during the first 9 months after ISB. METHODS: A total of 521 adults scheduled for elective shoulder surgery performed with an ISB were included in this prospective study. The ISB procedure was standardized for all patients Acute complications were recorded. Patients were observed daily (for 10 days) for paresthesias, dysesthesias, pain not related to surgery, and muscular weakness and were evaluated at 1, 3, 6, and 9 months after surgery. Persistence of paresthesias dysesthesias, pain not related to surgery, or muscular weakness was investigated at 1 or 3 months by means of electroneuromyography. Final evaluation was performed at 9 months. RESULTS: A total of 520 patients completed the study; one was excluded after surgical axillary nerve damage. Two hundred thirty-four patients had an interscalene catheter. Acute complications consisted of one pneumothorax (0.2%) and one episode of central nervous system toxicity (incoherent speech; 0.2%). A 10 days, 74 patients (14%) were symptomatic, and none had muscular weakness. At 1 month, 41 patients (7.9%) had symptoms, and none had muscular weakness. Thirty patients under went electroneuromyography; sulcus ulnaris syndrome (n = 8) carpal tunnel syndrome (n = 2), and complex regional pain syndrome (n = 1) were diagnosed. At 3 months 20 patient (3.9%) were symptomatic, and none had muscular weakness All underwent electroneuromyography; carpal tunnel syndrome (n = 2), complex regional pain syndrome (n = 4), plexus neuropathy (n = 1), and plexus damage (n = 1) were diagnosed. At 6 months, 5 patients (0.9%) were symptomatic. At 9 months 1 patient (0.2%) had persistence of dysesthesia. CONCLUSIONS: Interscalene brachial plexus block performed with a standardized technical approach, material, and drugs is associated with an incidence of short- and severe long-term complications of 0.4%. In case of persistent paresthesia, dysesthesia, or pain not related to surgery after ISB, sulcus ulnaris syndrome, carpal tunnel syndrome, or complex regional pain syndrome should be excluded since specific treatment may be required.

Adolescent↗
PubMed2001

The enantiomers: revolution or evolution.

The use of single stereoisomers are gaining popularity in the world of anesthesiology. The reduced costs of production have made these compounds available for clinical application. The majority of drugs used in anesthesiology such as ketamine, isoflurane, etomidate, atracurium, bupivacaine and ropivacaine have an asymmetric carbon, and are still used primarily as racemic mixtures (1:1 mixture of R and S enantiomers). Among local anesthetics, the S enantiomers often have favorable biological properties. This insight has led to the development of ropivacaine. Ropivacaine is the first local anesthetic marketed as pure S-(-) enantiomer. Its pharmacodynamic and pharmacokinetic profile is similar to that of bupivacaine, but in vitro and in vivo studies have shown that ropivacaine is less cardiotoxic. Clinical data suggests that ropivacaine has a greater margin of safety than bupivacaine, which is necessary for further expanding the application of regional anesthesia. The time has come for the use of single enantiomers in regional and general anesthesia

Anesthetics↗
PubMed2001

Nerve injury associated with regional anesthesia.

Neural damage is a possible consequence of general anesthesia, central nervous system blockade, and regional anesthesia. Dainage may be caused by ischaemic and mechanical or chemical factors, which may occur either alone or in combination. Neural damage may be secondary to prolonged and severe arterial hypotension compromising blood supply to the cord, a spinal haematoma whose main etiological factor is a coagulation abnormality, an intraneural injection, and peripheral neuropathy related to perioperative positioning. Mechanical trauma by the needle bevel is an important factor contributing to neuropathy. Neurological complications may also result from a direct neurotoxic effect of local anesthetic agents which is concentration and dose-dependent. A better understanding of these mechanisms will provide a reliable basis for the development of improved pharmaceutical therapy.

Anesthesia, Conduction↗
PubMed2001

From cocaine to ropivacaine: the history of local anesthetic drugs.

In 1850, about three centuries after the conquest of Peru by Pizzaro, the Austrian von Scherzer brought a sufficient quantum of coca leaves to Europe to permit the isolation of cocaine. As suggested by his friend Sigmund Freud, descriptions of the properties of the coca prompted the Austrian Koller to perform in 1884 the first clinical operation under local anesthesia, by administration of cocaine on the eye. The use of cocaine for local and regional anesthesia rapidly spread throughout Europe and America. The toxic effects of cocaine were soon identified resulting in many deaths among both patients and addicted medical staff. Local anesthesia was in a profound crisis until the development of modern organic chemistry which led to the synthesis of pure cocaine in 1891. New amino ester local anesthetics were synthesized between 1891 and 1930, such as tropocaine, eucaine, holocaine, orthoform, benzocaine, and tetracaine. In addition, amino amide local anesthetics were prepared between 1898 and 1972 including nirvaquine, procaine, chloroprocaine, cinchocaine, lidocaine, mepivacaine, prilocaine, efocaine, bupivacaine, etidocaine, and articaine. All of these drugs were ostensibly less toxic than cocaine, but they had differing amounts of central nervous system (CNS) and cardiovascular (CV) toxicity. Bupivacaine is of special interest because of its long duration of action and history of clinical application. Synthesized in 1957, the introduction of bupivacaine on the market in 1965 paralleled the progressive and cumulative reports of CNS and CV toxicity, leading to the restriction of its use and the identification of a special therapy-resistant CV toxicity. Numerous experimental studies were conducted to identify the fine cellular mechanism of this toxicity, which refines our understanding of the action of local anesthetics. The identification of optically active isomers of the mepivacaine family led to the selection of ropivacaine, a pure S-(-) enantiomer, whose toxicology was selectively and extensively studied before its introduction on the market in 1996. During the rapid and extensive use of ropivacaine in the clinic, unwanted side-effects have been found to be very limited.

Amides↗
PubMed2000

Patient-controlled interscalene analgesia with ropivacaine 0.2% versus patient-controlled intravenous analgesia after major shoulder surgery: effects on diaphragmatic and respiratory function.

BACKGROUND: The authors compared the effects of patient-controlled interscalene analgesia (PCIA) with ropivacaine 0.2% and patient-controlled intravenous analgesia (PCIVA) with opioids on hemidiaphragmatic excursion and respiratory function after major shoulder surgery. METHODS: Thirty-five patients scheduled for elective major shoulder surgery were prospectively randomized to receive either PCIA or PCIVA. All patients received an interscalene block before surgery. In the PCIA group, a catheter was introduced between the anterior and middle scalene muscles. Six hours after the initial block, patients received for 48 h either a continuous infusion of 0.2% ropivacaine through the interscalene catheter at a rate of 5 ml/h plus a bolus dose of 3 or 4 ml with a lockout time of 20 min (PCIA group) or a continuous intravenous infusion of nicomorphine at a rate or 0.5 mg/h plus a bolus dose of 2 or 3 mg with a lockout time of 20 min (PCIVA group). Hemidiaphragmatic excursion and respiratory function were assessed with the patient in a 45 degrees semirecumbent position the day before the operation and 20 min (in the operating room), 24 h, and 48 h after the initial block by means of ultrasonography and spirometry, respectively. Pain relief was regularly assessed, side effects were noted, and patient satisfaction was rated 6 h after the end of the study. RESULTS: Hemidiaphragmatic excursion was similar in the two groups 20 min after interscalene block. Hemidiaphragmatic excursion was increased in the PCIA group on the nonoperated side 24 and 48 h after the interscalene block (P < 0.05). Pulmonary function was similar in the two groups at each time. Pain was better controlled in the PCIA group at 12 and 24 h (P < 0.05). The incidence of nausea and vomiting were 5.5% versus 60% for the PCIA and PCIVA groups, respectively (P < 0.05). Patient satisfaction was greater in the PCIA group (P < 0.05). CONCLUSIONS: The use of PCIA or PCIVA techniques to provide analgesia after major shoulder surgery is associated with similar effects on respiratory function. In the PCIA group, hemidiaphragmatic excursion showed a significantly greater amplitude 24 and 48 h after the initial block on the nonoperated side. The PCIA technique provided better pain control, a lower incidence of side effects, and a higher degree of patient satisfaction.

Adult↗
PubMed2000

Plasma and cerebrospinal fluid concentration of neuropeptide Y, serotonin, and catecholamines in patients under propofol or isoflurane anesthesia.

Propofol is a widely used anesthetic for both induction and maintenance of anesthesia during surgery. A strong feeling of hunger has been reported during the early recovery period after propofol anesthesia. We have investigated the effect of propofol on appetite in 10 patients undergoing a craniotomy and in parallel measured neuropeptide Y (NPY), catecholamines, and serotonin levels in the cerebrospinal fluid and plasma during anesthesia. Ten patients anesthetized with a volatile agent (isoflurane) served as a control group. Plasma NPY and catecholamines levels were not affected by surgery at any time. We observed a strong increase in NPY concentrations in the cerebrospinal fluid independently of the anesthetic technique agent used, whereas catecholamines were unchanged. We found that serotonin concentrations decreased significantly in the plasma (but not in the cerebrospinal fluid) of patients treated by propofol when compared with the control group; this decrease was associated with an increase of hunger early postoperatively. We concluded that the proappetite effect of propofol is mediated through a decrease of serotonin at the peripheral level.

Adult↗
PubMed1999

Ondansetron is effective to treat spinal or epidural morphine-induced pruritus.

BACKGROUND: Spinally and epidurally administered morphine is frequently associated with pruritus. Isolated case reports indicate that ondansetron may be effective in this context. This study aims to investigate the effectiveness of ondansetron to treat this side effect. METHODS: In a prospective, randomized, double-blind, placebo-controlled study, 100 patients with pruritus (> 4 on a visual analog scale, on which 0 represents no pruritus and 10 represents worst pruritus imaginable) after spinal or epidural administration of morphine, received either 8 mg ondansetron intravenously (ondansetron group) in 100 ml NaCl 0.9% or vehicle (placebo group). A decrease of more than 4 points on the visual analog scale 60 min after treatment was considered a success. Changes in levels of pain and sedation, hemodynamic values, and other side effects were checked regularly. The presence or absence of pruritus was assessed for the last time 24 h later. RESULTS: The two groups were similar for demographic characteristics, the route of administration of morphine, and severity of pruritus at the beginning of the study. The ondansetron group showed a success rate of 70% versus 30% for the placebo group (P > 0.05). Among the successfully treated patients, three (9%) in the ondansetron group and six (40%) in the placebo group reported the recurrence of pruritus (P < 0.05). Among the successfully treated patients, none complained of residual pruritus 24 h later. No changes in pain or sedation levels were noted. Hemodynamic values remained stable, hemoglobin oxygen saturation did not decrease, and no other side effects were observed. CONCLUSION: The administration of 8 mg ondansetron intravenously is an effective treatment for spinally or epidurally administered morphine-induced pruritus. In this clinical condition the treatment is safe and well tolerated.

Analgesics, Opioid↗