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Biomedical subjects

Marc E Gentili

Publications and source records attributed to Marc E Gentili.

16 recordsLinked to original sources
PubMed2004

Influence of sensory and proprioceptive impairment on the development of phantom limb syndrome during regional anesthesia.

BACKGROUND: The relation between impairment of sensorimotor function and occurrence of phantom limb syndrome (PLS) during regional anesthesia has not been described. This study assessed the temporal relation between PLS and the progression of sensorimotor impairment during placement of a brachial plexus nerve block. METHODS: Fifty-two patients had their arm randomly placed either alongside their body (group A) or in 90 degrees abduction (group B) immediately after brachial plexus nerve block placement. Responses to pin prick, cold, heat, touch, proprioception, and voluntary movement were assessed every 5 min for 60 min. Meanwhile, patients described their perceptions of the size, shape, and position of their anesthetized limb. RESULTS: Phantom limb syndrome occurred 19 +/- 9 min after nerve block placement. Proprioception was impaired and abolished after 22 +/- 9 and 43 +/- 17 min, respectively (P < 0.05 vs. PLS onset). When PLS occurred, responses to pin prick, cold, heat, and proprioception were abolished in 96, 94, 87, and 4% of patients, respectively. Patients were more likely to feel their anesthetized limb in adduction and in abduction in groups A and B (P < 0.05 vs. group A), respectively. After PLS had become motionless, two stereotyped positions were identified: arm adduction, elbow flexion, hand over the abdomen (68% of group A patients) and arm abduction, elbow flexion, hand held close to the homolateral ear (48% of group B patients). CONCLUSIONS: This study provides a better understanding of the determinants of PLS by showing that the final position of PLS is related both to the abolition of proprioception and the initial position of the anesthetized limb.

Adult↗
PubMed2004

Time sequence of sensory changes after upper extremity block: swelling sensation is an early and accurate predictor of success.

BACKGROUND: Sensory assessment to estimate spread and effectiveness of a peripheral nerve block is difficult because no clinical test is specific for small sensory fibers. Occurrence of a swelling illusion (SI) during a peripheral nerve block corresponds to the impairment of small sensory fibers. The authors investigated the usefulness of SI in predicting successful peripheral nerve block by assessing the temporospatial correlation between progression of sensory impairment in cutaneous distributions anesthetized and localization of SI during peripheral nerve block installation. METHODS: Interscalene, infracoracoid, or sciatic nerve blocks were performed using a nerve stimulator and 1.5% mepivacaine in 53 patients, with a total of 201 nerves to be anesthetized. Pinprick, cold, warm, touch, and proprioception were assessed every 3 min, while patients were asked to describe their perception of size and shape of their anesthetized limb and localization of these illusions. Data are presented as mean +/- SD and percentage (95% confidence interval). RESULTS: Failure occurred in 12 cutaneous distributions out of a total of 201 theoretically blocked nerves. SI appeared earlier than warmth impairment (4.3 +/- 2.7 vs. 6.2 +/- 2.0 min; P < 0.05), always corresponding to successfully anesthetized cutaneous distributions, with the exception of 1 patient, who developed SI in 2 cutaneous distributions while sensory testing indicated failure in 1 distribution. SI successfully predicted the blockade of a cutaneous distribution with a sensitivity of 1.00 (0.98-1.00), a specificity of 0.92 (0.65-0.99), and an accuracy of 0.99 (0.97-1.00). CONCLUSIONS: Swelling illusion may provide an early assessment of the success of a peripheral nerve block in unsedated patients.

Adult↗
PubMed2002

The addition of tramadol to lidocaine does not reduce tourniquet and postoperative pain during iv regional anesthesia.

PURPOSE: We conducted a prospective, randomized, double-blind study to determine whether the combination of tramadol with lidocaine 0.5% had an analgesic effect on tourniquet pain during iv regional anesthesia and also on postoperative pain. METHODS: Thirty patients scheduled for carpal tunnel decompression were included in the study. Each patient received 3 mg.kg(-1) of plain lidocaine 0.5% with 100 mg of tramadol (Group T) or 2 mL of isotonic saline (Group C). The mixture was injected into the isolated and exsanguinated arm. Pain was assessed using a linear visual analog scale and a verbal rate scale during the surgical procedure and the postoperative period (240 min) and subsequently at interview at 24 hr. Analgesic consumption was recorded. RESULT: There was no difference in the pain scales and analgesic request at any of the time periods studied. CONCLUSION: We conclude, therefore, that for carpal tunnel operation under iv regional anesthesia, the combination of tramadol and lidocaine is not more effective than lidocaine alone.

Adult↗
PubMed2002

Severe respiratory failure after infraclavicular block with 0.75% ropivacaine: a case report.

Upper extremity surgery is usually performed with an axillary block. There is a risk of pneumothorax and phrenic nerve block when interscalene or supraclavicular block are used in day case surgery, or in patients with chronic obstructive pulmonary disease. The infraclavicular block is a simple, reliable, and easy to learn method to block the brachial plexus. No clinically relevant respiratory effects have been reported with infraclavicular block. Nonetheless, we report a case of a chronic obstructive pulmonary disease patient who developed severe respiratory failure requiring tracheal intubation after an infraclavicular block.

Acute Disease↗
PubMed2002

The effect of local anesthetics and amitriptyline on peroxidation in vivo in an inflammatory rat model: preliminary reports.

We studied the inhibition of peroxidation by local anesthetics in an inflammatory animal model. Inflammatory lipid peroxidation was assessed by the thiobarbituric assay in plasma from rats injected or not injected with carrageenan (Carra) and killed 1, 2, 4, 6, 12, and 24 h thereafter. Thiobarbituric acid reactive substances (TBARS) values in inflammatory animals were maximal 6 h after Carra administration. This result, in accordance with the evolution of paw edema width during time, supports that TBARS reflect the intensity of inflammation. Local anesthetics (bupivacaine, lidocaine, ropivacaine, or bupivacaine-loaded microspheres) or amitriptyline were injected in clinically relevant concentrations as a sciatic nerve block or intraperitoneally in inflamed animals. Ropivacaine did not exhibit any protective effect on Carra-induced lipid peroxidation in rats. With all the other drugs administered as a sciatic nerve block, the maximal TBARS increase was not observed at 6 h. Our conclusion is that bupivacaine (plain or encapsulated), lidocaine, and amitriptyline in clinically relevant concentrations administered via the sciatic nerve showed antioxidant properties toward lipid peroxidation induced by Carra inflammation. Intraperitoneal injection of those drugs gave the same effect as nerve block; this result suggests that their mechanism of action is not strictly limited to the nerve. IMPLICATIONS. We investigated the antioxidant effects of local anesthetics and amitriptyline in an inflammatory rat model. Amitriptyline exhibits antioxidant properties per se, whereas lidocaine and bupivacaine (plain or encapsulated) seem to inhibit the peroxidation process. This may have future application in limiting toxic oxygen metabolite production during the inflammatory process.

Amides↗
PubMedDate not supplied

Sciatic nerve block with bupivacaine-loaded microspheres prevents hyperalgesia in an inflammatory animal model.

PURPOSE: The aim of this study was to evaluate the effect of different durations of local anesthetic neural blockade on hyperalgesia after carrageenan infiltration in a rat model. METHODS: Inflammation was obtained by injection of carrageenan in the righ hind paw. Hyperalgesia was determined by measuring the threshold of response to increasing mechanical stimuli on the contralateral and on the ipsilateral paw. The development of edema was measured. After identification of the sciatic nerve by nerve stimulation, blockade was performed either one hour before or after carrageenan infiltration. Animals were randomly assigned into three groups: without sciatic nerve block (control group; n = 20), block with bupivacaine (B) and block with bupivacaine-loaded microspheres (B-Ms) injection before or after carrageenan infiltration (n = 10 for each group). RESULTS: Carrageenan infiltration in the control group induced a severe ipsilateral and contralateral hyperalgesia. After blockade with B (duration = 2 +/- 0.5 hr) hyperalgesia was present and delayed only by the duration of the local anesthetic effect. A longer duration of block achieved with B-Ms (duration greater than five hours), was associated with the absence of development of both ipsilateral and contralateral hyperalgesia. No preemptive effect was recorded. CONCLUSION: B-Ms as a drug delivery system prolongs the duration of neural blockade and avoids hyperalgesia phenomena in this rat model of inflammation.

Anesthetics, Local↗
PubMedDate not supplied

A comparison of a single-stimulation lateral infraclavicular plexus block with a triple-stimulation axillary block.

BACKGROUND AND OBJECTIVES: A single-stimulation infraclavicular brachial plexus block (ICB) is safe and easy to perform, although underused. This technique was compared with a triple-stimulation axillary block (AxB). METHODS: One hundred patients scheduled for hand and forearm surgery were randomly allocated to 2 groups. ICB was performed with the needle inserted above the coracoid process in the upper lateral angle of the infraclavicular fossa and directed vertically until nerve stimulation elicited a distal motor response (median, radial, or ulnar). A single 40-mL bolus of ropivacaine 0.75% was injected. In the AxB group, 3 stimulations were performed to identify median or ulnar, radial, and musculocutaneous nerves, followed by an infiltration near the medial brachial and antebrachial cutaneous nerves. The same 40 mL of ropivacaine 0.75% was injected. Sensory and motor blocks were assessed at 5-minute intervals over 30 minutes. RESULTS: The time to block performance was shorter in the ICB than in the AxB group (2.5 +/- 1.9 minutes v 6.0 +/- 2.8 minutes, P <.001). The success rate (complete block in median, radial, ulnar, musculocutaneous, and medial antebrachial cutaneous nerves) was comparable in the 2 groups (90% v 88% in groups ICB and AxB, respectively). Block extension was comparable, except for a higher rate of block completion in the axillary nerve distribution in group ICB and in the medial brachial cutaneous nerve in group AxB. The onset of each nerve block was comparable except for a faster onset for the musculocutaneous nerve in group AxB (8 +/- 3 v 10 +/- 5 minutes). CONCLUSION: A single shot ICB is equally effective as a triple-nerve stimulation AxB.

Adult↗
PubMedDate not supplied

Lidocaine priming reduces tourniquet pain during intravenous regional anesthesia: A preliminary study.

BACKGROUND AND OBJECTIVES: Tourniquet pain often limits the use of intravenous regional anesthesia (IVRA). Intravenous (IV) lidocaine has been shown to be effective in the management of acute and neuropathic pains. We tested the hypothesis that a priming IV injection of lidocaine might have an analgesic effect on tourniquet pain during IVRA. METHODS: A prospective, randomized, double- blind study was conducted on 40 patients scheduled for carpal tunnel decompression. No sedation was given. Each patient received either 1 mg/kg of IV lidocaine (group L) or 0.1 mL/kg of IV isotonic saline (group control = C) 5 minutes before IVRA. Thereafter, they received 3 mg/kg of plain 0.5 % lidocaine into the isolated and exsanguinated arm. A double-cuffed tourniquet was used. Pain at the tourniquet and the surgical sites was assessed every 5 minutes using a linear visual analog scale (VAS) and a verbal rating scale (VRS) during the surgical procedure and the immediate postoperative period (60 minutes). RESULTS: Demographic data and duration of proximal and distal tourniquet were similar in each group. Significant differences in the pain scales were observed for the distal tourniquet at tourniquet inflation time and 15 minutes after (P =.03 and.005, respectively) in the group L. For the proximal tourniquet, only the VRS was significantly improved (P =.03). No analgesic benefit was observed in the immediate postoperative period. CONCLUSIONS: Priming IV lidocaine when compared with isotonic saline is effective in reducing tourniquet pain in IVRA.

Anesthesia, Conduction↗