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H Bouaziz

Publications and source records attributed to H Bouaziz.

65 records · Page 4Linked to original sources
PubMed1993

Endogenous bradykinin activity in Dahl rats.

We assessed the participation of endogenous bradykinin (BK) on basal blood pressure (BP) regulation in anesthetized Dahl-sensitive (DS) and Dahl-resistant (DR) rats receiving different NaCl diets. Four groups of Dahl rats were studied after 5 weeks of high (H) = 7% or low (L) = 0.4% NaCl diet (DSH, n = 9; DSL, n = 11; DRH, n = 9; DRL, n = 10). Endogenous BK activity was assessed with a continuous intraarterial (i.a.) infusion of the specific BK antagonist (B4146 100 micrograms/kg/min) for 10 min. Sensitivity to exogenous BK was tested 30 min after the end of the infusions, with bolus intraarterial (i.a.) injections of BK (0.1, 0.5, 1, and 5 micrograms). DSH had a significantly higher (p < 0.0001) basal mean BP (MBP) as compared with the three other groups: DSH = 185 +/- 7 mm Hg (mean +/- SEM), DSL = 143 +/- 5 mm Hg, DRH = 132 +/- 10 mm Hg, and DRL = 134 +/- 6 mm Hg. BK antagonist infusion increased MBP by 13.2 +/- 1.5 mm Hg in DSL rats, by 6.8 +/- 1.6 mm Hg in DRL, by 4.7 +/- 1.6 mm Hg in DRH, and by 1.1 +/- 8 mm Hg in DSH. Statistical analysis showed that the high NaCl diet significantly decreased the response to the BK antagonist in DS (p < 0.001) but not in DR rats. MBP response to exogenous BK was similar in all groups. These results show that endogenous BK has a vasodepressor effect on DS rats fed a low NaCl diet. This effect is suppressed after a high-salt diet.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1992

Serum concentrations of local anaesthetics following intraperitoneal administration during laparoscopy.

The present study is a comparison of the pharmacokinetics of four local anaesthetics injected double blind in the right subdiaphragmatic area during outpatient laparoscopy performed under standard general anaesthesia in 28 young women. 80 ml of one of the following solutions was injected: Group A 0.5% plain lidocaine (n = 7), Group B 0.5% lidocaine with 1/320.000 adrenaline (n = 8), Group C 0.5% lidocaine with 1/800.000 adrenaline (n = 7), and Group D 0.125% bupivacaine with 1/800.000 adrenaline (n = 6). Blood samples were collected over 360 min from an iv catheter and serum concentrations were measured by gas chromatography. No adverse effects occurred in the study period. In Group A (plain lidocaine), Cmax was significantly higher and tmax significantly earlier than in Groups B and C (lidocaine with adrenaline). A toxic level was not found after either solution in any patient. The intraperitoneal use of doses of 400 mg lidocaine or 100 mg bupivacaine for perioperative analgesia was safe and solutions of lidocaine containing adrenaline appeared to pose even less risk than plain solutions.

Adult↗
PubMed1992

Ventilatory effects of epidural clonidine during the first 3 hours after caesarean section.

Many authors have shown the analgesic efficacy of 150-800 micrograms of epidural clonidine in the postoperative period. Its use as an analgesic after caesarean section has recently been studied with higher dosages (400-800 micrograms). Our study aimed at assessing the analgesic and ventilatory effects of two smaller doses of epidural clonidine (150 and 300 micrograms), which were compared to the effects of 10 mg of parenteral morphine (M) during the first 3 h after caesarean section. The duration of the analgesic effect was longest with 150 micrograms of epidural clonidine. Arterial blood pressure decreased from 30 min after the injection to the end of the study in both epidural clonidine groups. A marked sedation was observed in patients receiving 300 micrograms of epidural clonidine and was frequently associated with snoring, obstructive apnoea and episodes of arterial oxygen desaturation. We conclude that 150 micrograms of epidural clonidine provides better and longer analgesia after caesarean section than 10 mg of parenteral morphine, and seems preferable to higher doses (300 micrograms) in this setting, since 300 micrograms of epidural clonidine may produce unacceptable respiratory obstructive disturbances.

Analgesia, Epidural↗
PubMed1992

Physiological and pharmacological changes in the carotid artery pressure-volume curve in situ in rats.

AIM: To measure the mechanical properties of the rat carotid artery as affected by physiological and pharmacological changes. METHODS: We used an in situ measurement method that did not affect the anatomy, vascularization or innervation of the carotid artery, in normotensive and in spontaneously hypertensive rats (SHR), to evaluate the effects of ageing, hypertension and acute or chronic drug-induced vasorelaxation. RESULTS: The compliance-pressure curve was characterized, under baseline conditions, by two phases, an ascending component in the lower pressure ranges and a descending component in the higher pressure ranges. In younger or older normotensive rats the maximum value of carotid compliance was observed for values of transmural pressure that approximated those of the operating mean blood pressure. For any given value of transmural pressure, carotid compliance was lower in the hypertensive rats, whether younger (3 months) or older (18 months), than in normotensive rats. This finding was particularly striking for transmural pressures below 125 mmHg, and held true even after the administration of potassium cyanide. Consequently, the reduced compliance in the hypertensive rats was attributed predominantly to structural changes in the arterial wall. Moreover, in the hypertensive rats there was a dissociation between the operating arterial blood pressure level and the maximum value of carotid arterial compliance. Thus in young SHR, whereas the operating systemic blood pressure was shifted toward higher values (> 175 mmHg), the maximum value of carotid compliance was observed for pressure levels close to 125 mmHg. This dissociation was more pronounced in older SHR (mean blood pressure 200 mmHg; maximum compliance 75 mmHg). CONCLUSIONS: The acute administration of vasodilators or of potassium cyanide induces relaxation of vascular smooth muscle and increases compliance for distension pressures of up to 125 mmHg. Since the drugs had no effects on arterial compliance at higher pressure levels, we conclude that in SHR acute vasorelaxation can increase operating compliance only if blood pressure is reduced. In contrast, chronic treatment with vasodilating agents is able to increase compliance even for higher blood pressure levels. Therefore, we suggest that chronic treatment can improve the elastic properties of the arterial wall through changes in the arterial wall structure.

Aging↗
PubMed1989

[Block of the superior laryngeal nerve for ORL endoscopy. Description of a simplified technique].

The usual anterior and lateral routes used for superior laryngeal (SL) nerve blocks are not often used because too difficult to carry out. A simpler and easier technique is described, which blocks the SL nerve at the level of the greater cornu of the hyoid bone. Because the nerve is not located accurately with this technique, a larger volume of local anaesthetic is required. This technique was tested in 31 patients scheduled for endoscopies with rigid tubes. The mean duration of endoscopy was 30 +/- 10 min. The use of 8 ml 1% lidocaine for the block 30 min surgical anaesthesia. In 2 patients, the SL nerve block alone was sufficient. In 26 others a complement with a benzodiazepine (flunitrazepam, n = 9, mean dose 0.8 mg; midazolam, n = 17, mean dose 5 mg) was required. In 4 of these patients, attempts of oesophagoscopy gave rise to hypertension and tachycardia. General anaesthesia with propofol and tracheal intubation were therefore used. In the last 3 patients, intercricothyroid jet ventilation was used, requiring general anaesthesia (propofol and succinylcholine). The SL nerve block was satisfactory in 24 patients with total vocal cord paralysis and no haemodynamic reaction to painful stimuli in the blocked area. No complication was observed. It is concluded that this technique is useful and easier to carry out than the usual ones.

Anesthesia, General↗
PubMedDate not supplied

Survey of regional anesthetic practice among French residents at time of certification.

BACKGROUND AND OBJECTIVES: A survey of anesthesia practice was conducted among French residents in anesthesia at the end of their training. This study was performed mainly to evaluate the residents' experience in peripheral nerve blocks. METHODS: Two short clinical cases were proposed to all French residents during a telephone interview immediately before their certification. The first described the case of a young asthmatic patient admitted for an elbow fracture. The second described an elderly woman with severe aortic stenosis admitted for a supracondylar fracture of the femur. A questionnaire had been prepared and was filled in during the interview. Each resident was asked to answer according to the actual choice he or she would have made. For both cases, when general anesthesia was chosen first, the next question was to discuss which regional anesthesia would be used if general anesthesia had to be discarded. In that way, the practical knowledge about most common peripheral nerve blocks learned during residency was investigated. RESULTS: Of 77 residents registered as being at the end of their residency, 8 were on either sabbatical or maternity leave. Regional anesthesia was the first choice in 78% and 57% of cases for the first and second clinical cases, respectively. The regional anesthetic techniques chosen were axillary block (66%), interscalene block (31%), and intravenous regional anesthesia (3%) for case 1 and combined lumbar plexus and sciatic block (36%), epidural anesthesia (30%), single-shot spinal anesthesia (18%), and continuous spinal anesthesia (16%) for case 2. Throughout the residency of the group, 32 +/- 2 axillary blocks, 12 +/- 2 interscalene blocks (axillary vs interscalene, P < .0001), 21 +/- 3 femoral blocks, and 10 +/- 2 sciatic blocks (femoral vs sciatic, P < .0001) had been performed (mean +/- SEM). They had also performed 2.5 +/- 0.5 continuous spinal anesthesias and 17 +/- 3 intravenous regional anesthesias respectively. Upper extremity blocks were more often used during residency than lower extremity blocks (44 +/- 3 vs 31 +/- 4, P < .01). A peripheral nerve stimulator was routinely used by 83% of residents. CONCLUSION: French residents in anesthesiology at time of certification are better trained for peripheral nerve blocks of the upper extremity than for those of the lower extremity. Axillary plexus and femoral nerve block are the most widely used blocks, probably reflecting the techniques the most mastered among teachers. Finally, the extensive use of a peripheral nerve stimulator by residents is probably the result of the widespread use of this device by teachers in France.

Adult↗
PubMedDate not supplied

Infraclavicular block with lateral approach and nerve stimulation: extent of anesthesia and adverse effects.

BACKGROUND AND OBJECTIVES: The infraclavicular approach to the brachial plexus is little used despite theoretical advantages of the technique. Using a vertical paracoracoid approach, we assessed the extent of the sensory block and the incidence of adverse effects. METHODS: After obtaining informed consent, 100 patients undergoing surgical procedures distal to the elbow were evaluated. The block was performed using a peripheral nerve stimulator. The puncture site was located in the infraclavicular fossa; the direction of the insulated needle was perpendicular to the skin. Motor response was sought in the hand or wrist at < or = 0.6 mA. A total of 40 mL of 1.5% mepivacaine was administered as a single injection. The sensory block was evaluated every 5 minutes for 30 minutes before surgery in the cutaneous distribution of terminal branches of the brachial plexus. RESULTS: When one considers the cutaneous distributions of the median, ulnar, radial, and musculocutaneous nerves, the success rate was 89% for surgery without need for additional peripheral nerve blocks or general anesthesia. In contrast, cutaneous areas innervated by the axillary and medial cutaneous nerves were rarely anesthetized. We were unable to demonstrate a correlation between the intensity of the stimulation and the success of the block. On the other hand, a correlation was found between tourniquet sensation and the absence of anesthesia of the medial cutaneous nerve of the arm. Local anesthetic toxicity, Horner's syndrome, and vascular puncture were respectively observed in 1%, 4%, and 5% of cases. The depth of the needle introduction was correlated with the body mass index (P <.001; r =.63). CONCLUSION: Single injection infraclavicular block, using a vertical paracoracoid approach, appears suitable for surgery distal to the elbow. Selective anesthesia of the medial cutaneous nerve is useful in improving tolerance of the tourniquet.

Anesthetics, Local↗
PubMedDate not supplied

Subarachnoid neostigmine potentiation of alpha 2-adrenergic agonist analgesia. Dexmedetomidine versus Clonidine.

BACKGROUND AND OBJECTIVES: Intraspinally administered alpha 2-adrenergic agonists produce analgesia in part by causing spinal acetylcholine and nitric oxide (NO) release. Clonidine-induced analgesia is enhanced by subarachnoid neostigmine and inhibited by N-methyl-L-arginine (NMLA), a blocker of NO synthesis. The authors tested whether dexmedetomidine, an alpha 2-adrenergic agonist with greater intrinsic efficacy than clonidine, would be similarly affected by neostigmine and NMLA. METHODS: Drugs were administered subarachnoid to 22 chronically prepared ewes, and antinociception was determined by a noxious mechanical stimulation. Sheep received subarachnoid saline, neostigmine, or NMLA, followed by cumulative doses of clonidine or dexmedetomidine. Neostigmine was injected either 20 or 60 minutes prior to beginning cumulative dosing with the alpha 2-adrenergic agonist. RESULTS: Both clonidine and dexmedetomidine produced dose-dependent antinociception with similar potency (ED50 was 61 +/- 26 micrograms for clonidine and 65 +/- 24 micrograms dexmedetomidine). Neostigmine pretreatment 20 minutes before dosing potentiated clonidine's dose response (ED50 was reduced to 6.8 +/- 2.3 micrograms), but had no effect on dexmedetomidine (ED50 27 +/- 6.1 micrograms). Neostigmine pretreatment 60 minutes before dosing potentiated both clonidine (ED50 was reduced to 11.8 +/- 5.1 micrograms) or dexmedetomidine (ED50 was reduced to 10 +/- 2.1 micrograms). The NMLA did not affect antinociception from dexmedetomidine. CONCLUSIONS: These data are in agreement with previous hemodynamic studies suggesting that neostigmine has a slow onset of action after subarachnoid administration. That clonidine is potentiated more than dexmedetomidine by neostigmine pretreatment at 20 minutes likely may reflect the lower intrinsic efficacy of clonidine. Alternatively, since acetylcholine can cause NO synthesis, lack of effect of NMLA on dexmedetomidine implies that analgesia from this drug is less reliant on acetylcholine-NO mechanisms than clonidine. The large potentiation observed between neostigmine and these alpha 2-adrenergic agonists carries important clinical implications.

Adrenergic alpha-2 Receptor Agonists↗