Biomedical subjects
Publications and source records attributed to Jacques Ripart.
We report a case of trismus caused by tetanus in an 80-yr-old woman who developed severe and painful masseter spasms during which she violently bit the tip of her tongue with her dentures. Bilateral mandibular blocks were performed to remove the dentures. The patient fully recovered. We suggest that mandibular blocks are a useful tool in the management of oral events during trismus in conscious patients.
We previously showed that, in comparison with term healthy parturients, patients with severe preeclampsia had a less frequent incidence of spinal hypotension, which was less severe and required less ephedrine. In the present study, we hypothesized that these findings were attributable to preeclampsia-associated factors rather than to a smaller uterine mass. The incidence and severity of hypotension were compared between severe preeclamptics (n = 65) and parturients with preterm pregnancies (n = 71), undergoing spinal anesthesia for cesarean delivery (0.5% bupivacaine, sufentanil, morphine). Hypotension was defined as the need for ephedrine (systolic blood pressure <100 mm Hg in parturients with preterm fetuses or 30% decrease in mean blood pressure in both groups). Apgar scores and umbilical arterial blood pH were also studied. Neonatal and placental weights were similar between the groups. Hypotension was less frequent in preeclamptic patients than in women with preterm pregnancies (24.6% versus 40.8%, respectively, P = 0.044). Although the magnitude of the decrease in systolic, diastolic, and mean arterial blood pressure was similar between groups, preeclamptic patients required less ephedrine than women in the preterm group to restore blood pressure to baseline levels (9.8 +/- 4.6 mg versus 15.8 +/- 6.2 mg, respectively, P = 0.031). The risk of hypotension in the preeclamptic group was almost 2 times less than that in the preterm group (relative risk = 0.603; 95% confidence interval, 0.362-1.003; P = 0.044). The impact of Apgar scores was minor, and umbilical arterial blood pH was not affected. We conclude that preeclampsia-associated factors, rather than a smaller uterine mass, account for the infrequent incidence of spinal hypotension in preeclamptic patients.
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BACKGROUND: The purpose of this study was to evaluate the efficacy and safety of episcleral single-injection anesthesia in a large number of patients. METHODS: Over a period of 5 yr, in four institutions, anesthesiologists involved in this prospective study completed a standardized form to evaluate single-injection medial canthus high-volume episcleral anesthesia. The success rate of the block was rated according to an akinesia score. The study parameters included demographic data, surgical procedure, and anesthetic management. All patients were followed up at least until postoperative day 1, and all complications, pain, and discomfort were noted. Statistical analysis was done to assess the risk factors for complications. RESULTS: A total of 2,031 patients were included in the study. The most frequent surgical procedures performed were phacoemulsification and posterior chamber artificial lens implantation (91.0%). A total of 66 complications (3.3%) occurred in 60 patients. One patient had a retrobulbar hemorrhage, and 59 had one or two more minor incidents or pain/discomfort with the procedure. The complications consisted of subconjunctival hematoma (1.3%), ocular hypertonia (0.4%), and chemosis (0.30%). Statistical analysis revealed that inexperience in the technique represented a risk factor for complications. CONCLUSIONS: This is the first survey of a large experience in episcleral single-injection anesthesia, a form of anesthesia that does not preclude sharp-needle complications and does require training. Only one complication occurred among 2,031 patients; however, a larger number of patients is needed to definitively evaluate the safety of episcleral single-injection anesthesia.
BACKGROUND: The sensory blockade induced by a lidocaine-bupivacaine mixture combines the faster onset of lidocaine and the longer duration of bupivacaine. The current study compared the effects of large doses lidocaine (16 mg/kg), bupivacaine (4 mg/kg), and a mixture of 16 mg/kg lidocaine-4 mg/kg bupivacaine on hemodynamic and cardiac electrophysiologic parameters in anesthetized and ventilated piglets. METHODS: After carotid artery cannulation, a double micromanometer measured mean aortic pressure, left ventricular end diastolic pressure, and the first derivative of left ventricular pressure. Electrocardiogram recording and a bipolar electrode catheter measured RR, PQ, QRS, QT C, JT C, AH, and HV intervals. Lidocaine, bupivacaine, or the mixture was administered intravenously over 30 s, and studied parameters were measured throughout 30 min. RESULTS: Mean aortic pressure decreased in all groups ( P < 0.05). The first derivative of left ventricular pressure was decreased in all groups ( P < 0.001) but to a greater extent with the mixture compared with lidocaine ( P < 0.04). RR, QT C, and JT C intervals were similarly increased in all groups ( P < 0.05). In all groups, PQ, AH, HV, and QRS intervals were widened ( P < 0.001). The lengthening of PQ was greater with bupivacaine ( P < 0.02). The lengthening of AH was greater and delayed with bupivacaine compared with lidocaine ( P < 0.03). The lengthening of HV and the widening of QRS were greater and delayed with bupivacaine ( P < 0.01). The widening of QRS was greater with the mixture than with lidocaine ( P < 0.01). CONCLUSIONS: The alterations of ventricular conduction parameters are greater with 4 mg/kg bupivacaine than with a mixture of 16 mg/kg lidocaine-4 mg/kg bupivacaine, whereas the hemodynamic parameters are similarly altered.
BACKGROUND: The purpose of this study was to compare parasacral and Winnie's single- or double-injection approaches for sciatic nerve block. METHODS: One hundred fifty adults scheduled to undergo lower limb surgery were randomized to receive on the sciatic nerve 20 ml ropivacaine, 0.75%: single bolus for parasacral and Winnie's single injection. For Winnie's double injection, the peroneal and tibial nerves received separately 10 ml plus 10 ml. Blocks were performed with the use of nerve stimulator (intensity < 0.5 mA, 1 Hz). For the parasacral method, a line was drawn between the posterior superior iliac spine and the ischial tuberosity; needle entry was at 6 cm inferior to the posterior superior iliac spine. RESULTS: The groups were similar. Time to perform the block was 2 (1-5) min for the parasacral method, with no difference from Winnie's single injection (3 [1-10] min), but was shorter with double injection (5.5 [2-15] min) (P = 0.0001). Onset of sensory block was similar in the parasacral (25 [7.5-50] min) and Winnie single-injection groups (25 [5-50] min) but significantly longer in the double-injection group (15 [5-50] min). Success rates for complete block were similar in the parasacral (66%) and Winnie's double-injection groups (68%) after 30 min but higher in the Winnie's single-injection group for tibial sensory and motor block (48%) (P < 0.017). CONCLUSION: Time to perform a parasacral block was short, and the parasacral approach had a high success rate and a short onset time. Therefore, this block might be a useful alternative to Winnie's modification for sciatic nerve block.
In this prospective cohort study, we compared the incidence and severity of spinal anesthesia (SA)-associated hypotension in severely preeclamptic (n = 30) versus healthy (n = 30) parturients undergoing cesarean delivery. After the administration of IV fluids, SA was performed with hyperbaric 0.5% bupivacaine, sufentanil, and morphine. Blood pressure (BP) was recorded before and at 2-min intervals for 30 min after SA. Clinically significant hypotension was defined as the need for ephedrine (systolic BP decrease to <100 mm Hg in healthy parturients or 30% decrease in mean BP in both groups). Despite receiving a smaller fluid volume (1653 +/- 331 mL versus 1895 +/- 150 mL; P = 0.005) and a larger bupivacaine dose (10.5 +/- 0.9 mg versus 10.0 +/- 0.7 mg; P = 0.019), the severely preeclamptic patients had a less frequent incidence of clinically significant hypotension (16.6% versus 53.3%; P = 0.006), which was less severe and required less ephedrine. The risk of hypotension was almost six times less in severely preeclamptic patients (odds ratio, 0.17; 95% confidence interval, 0.05-0.58; P = 0.006) than that in healthy patients.
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Neurolytic blockade is one of the therapeutic possibilities to treat spasticity of various muscles. In patients with spasticity of the adductor thigh muscles, a percutaneous approach to the obturator nerve is often difficult. We describe a new approach to the obturator nerve and we examine its feasibility. The second objective was to assess the efficacy of obturator neurolysis for the management of adductor thigh muscle pain and spasticity associated with hemiplegia or paraplegia. Nerve blocks were performed via a combined approach using fluoroscopy and nerve stimulation to identify the obturator nerve. Neurolysis was performed by injection of 65% ethanol. We performed 27 blocks in 23 patients. Technical evaluation was achieved in terms of number of attempted needle insertions, time to accurate location of the nerve and success rate. The efficacy of the block was assessed using four scores: degree of alleviation of muscle spasm and triple flexion of the lower limb, improvement of gait and facilitation of hygienic care. Success rate of the technique was 100% with a time to accurate nerve location of 130+/-35 s. Compared with scores measured immediately before the block, all studied parameters were significantly improved. Efficiency was significant on adductor muscle spasticity (p<0.001 at 1 day and p<0.01 at 60 and 120 months). Triple flexion was also significantly improved (p<0.05 from 1 to 120 days), as well as gait (p<0.02) and hygiene (p<0.01) scores. No complications occurred. The combined approach of the obturator nerve represents a new technique which proved to be accurate, fast, simple, highly successful and reproducible. Obturator neurolysis was confirmed as an efficient and cost-effective technique to reduce adductor muscle spasm and related pain and to improve gait and hygienic care in patients with neurological sequelae of stroke, head trauma or any lesion of the motor neurone.
BACKGROUND: The study was designed to compare the effects of equimolar concentrations of racemic bupivacaine, levobupivacaine, and ropivacaine on ventricular conduction, anisotropy, duration and homogeneity of refractoriness, and wavelengths, and to provide a potency ratio for effects on conduction velocity. METHODS: Isolated frozen rabbit hearts (which leave a thin layer of surviving epicardial muscle) were treated with 0.1, 1, and 10 mum racemic bupivacaine, levobupivacaine, or ropivacaine. Left ventricular longitudinal and transverse conduction velocities, anisotropic ratio, minimum pacing cycle length, use dependency, duration and dispersion of ventricular effective refractory period, and wavelengths were studied. A high-resolution mapping system was used for data acquisition. In addition to two-way analysis of variance for repeated measures, data for conduction velocities were fitted simultaneously using a nonlinear mixed-effect modeling program to allow intergroup comparison. RESULTS: Each agent induced a concentration- and use-dependent slowing of conduction velocities, with no change of the anisotropic ratio. The use-dependent effect of levobupivacaine is similar to that of racemic bupivacaine concerning longitudinal conduction velocity. Fitting of conduction velocities provided a racemic bupivacaine to levobupivacaine and to ropivacaine ratio of 1:1.38 for concentration effect at 1,000-ms pacing cycle length, and 1:0.74 for use-dependent effect at 600-ms pacing cycle length. Racemic bupivacaine and levobupivacaine prolonged the ventricular effective refractory period, whereas ropivacaine did not. No dispersion in ventricular effective refractory period values occurred. All three agents induced significant decreases in wavelengths. This effect was not different among groups. CONCLUSIONS: Differences among racemic bupivacaine, levobupivacaine, and ropivacaine at equimolar concentrations are mainly caused by the use-dependent effects on conduction velocities and the concentration-dependent effects on ventricular effective refractory period. Therefore, one must take into account the corresponding pacing rates when comparing the potency ratios of local anesthetics.
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Headaches were classified in 1988 by the International Headache Society (IHS). Postural headache is related to intracranial hypotension, most often secondary to lumbar puncture. We report three observations where headache of unknown cause led to the diagnosis of spontaneous intracranial hypotension.
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BACKGROUND AND OBJECTIVES: Parasacral sciatic nerve block has been shown to be easy to perform, but studies reported to date involve a total of only 155 patients. The aim of this study was to assess the efficacy of parasacral sciatic nerve block in a larger group of patients. METHODS: Four hundred consecutive parasacral blocks were evaluated prospectively. The level of expertise of the practitioner, the time to perform the block, the lowest current intensity of nerve stimulation, the injected volume, the onset time, the success or failure of the block, and complications were recorded. RESULTS: The time required to perform the block was 7 +/- 5 minutes. The lowest stimulation-current intensity was 0.4 +/- 0.1 mA, and the injected volume was 27 +/- 4 mL. The onset time was 13 +/- 7 minutes for both motor and sensory block in all nerve distributions. The success rate was 94% (376 of 400 cases). Nine supplemental injections were performed successfully, thus increasing the success rate to 96%. General anesthesia or heavy sedation was performed in 15 cases (3.8%). There was no difference in failure rate between more experienced and less experienced anesthesiologists. CONCLUSIONS: In this prospective 400-case study, we confirmed previous findings that the parasacral approach is effective, easy to perform, and easy to teach, even when performed by relatively inexperienced physicians. The parasacral approach is, therefore, an effective alternative to other approaches of sciatic nerve blockade.
BACKGROUND AND OBJECTIVES: For eye surgery, motor block is still often requested by the surgeon. For cataract surgery, rapid block resolution allows eyelids to move and allows eye-patch removal. Therefore, short-duration block is useful in early rehabilitation for ambulatory surgery. Lidocaine is classically assumed to have shorter duration than mepivacaine. Therefore, lidocaine alone might be considered as an alternative to mepivacaine. METHODS: In this randomized, double-blind study, we compared mepivacaine 2% (n = 22) and lidocaine 2% (n = 25) in 47 patients who received episcleral (sub-Tenon's) block for cataract surgery. Akinesia score was measured 1, 5, 10, and 15 minutes and 1, 2, 4, and 6 hours after the end of injection. Primary outcome was block duration (time from injection to full recovery). Secondary outcomes were time to block onset and best akinesia score for each patient. Complications were recorded. RESULTS: The 2 groups were similar for demographic and anesthetic features. We observed no significant difference between mepivacaine and lidocaine in terms of onset, quality of akinesia, and block duration. One case of ocular hypertonia and 1 case of strabismus were observed in the lidocaine group, which could be imputed to hyaluronidase unavailability during the study period or to increased lidocaine myotoxicity. CONCLUSIONS: We found no argument to favor lidocaine over mepivacaine in episcleral (sub-Tenon's) eye block, especially in terms of motor-block duration.