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Biomedical subjects

M Bouregba

Publications and source records attributed to M Bouregba.

8 recordsLinked to original sources
PubMed2000

The increase in CO2 production induced by NaHCO3 depends on blood albumin and hemoglobin concentrations.

OBJECTIVE: To evaluate the origin of H+ ions participating in the generation of CO2 coming from sodium bicarbonate infusion during metabolic acidosis. We hypothesized that these H+ ions come from a back-titration of the main non-bicarbonate buffers present in the blood, i. e. the hemoglobin and the albumin, and thus postulated that the rate of CO2 release from a bicarbonate load is dependent on the concentration of these buffers. DESIGN: Prospective clinical and experimental study. SETTING: Surgical intensive care unit of a university hospital. PATIENTS AND MATERIAL: (1) Sixteen stable sedated and artificially ventilated critically ill patients with a mild base deficit. (2) Acidotic human blood (bicarbonate 5 mM, pH 7.0) of hematocrit 5, 10, 20 and 40% regenerated from a mixture of frozen fresh plasma and packed red blood cells. INTERVENTIONS PATIENTS: infusion of 1.5 mmol/kg sodium bicarbonate over 5 min. Regenerated blood: 25 mM sodium bicarbonate load. MEASUREMENTS AND RESULTS PATIENTS: continuous measurement of CO2 production (VCO2) on the expired gas using a metabolic monitor and arterial blood gas analysis before (T0), at the end (T5) and at 10, 30 and 60 min after the beginning of the bicarbonate infusion. The increase in VCO2 was 18 +/- 7% leading to a rise in PaCO2 from 39.6 +/- 2.3 at T0 to 46.2 +/- 2.7 mmHg at T5. The increases in VCO2 and in PaCO2 were significantly correlated to the albumin (r = 0.73, p < 0.005 and r = 0.70, p < 0.005, respectively) and to the hemoglobin (r = 0.51, p < 0.05 and r = 0.65, p < 0.01, respectively) concentrations. Regenerated blood: gas analysis 1 min after the bicarbonate load. The increase in PCO2 was closely related to the hematocrit (Ht) of the blood as it was 15.9 +/- 7.5 mmHg for Ht 5%, 29.0 +/- 9.6 for Ht 10%, 44.2 +/- 5.9 for Ht 20% and 71.0 +/- 3.5 for Ht 40% (n = 5 for each, p < 0.001). CONCLUSIONS: The importance of the release of CO2 from a bicarbonate load is dependent on the concentration of the blood non-bicarbonate buffers. It is therefore likely that the adverse effects of bicarbonate therapy linked to the CO2 generation are more important in patients with high blood albumin and hemoglobin concentrations.

Acidosis↗
PubMed2000

Prolonged low-dose dopamine infusion induces a transient improvement in renal function in hemodynamically stable, critically ill patients: a single-blind, prospective, controlled study.

OBJECTIVE: To evaluate the length of the effects of long-term (48 hrs), low-dose dopamine infusion on both renal function and systemic hemodynamic variables in stable nonoliguric critically ill patients. DESIGN: Prospective, single-blind, controlled clinical study. SETTING: University hospital, 19-bed multidisciplinary intensive care unit. PATIENTS: Eight hemodynamically stable, critically ill patients with a mild nonoliguric renal impairment (creatinine clearance between 30 and 80 mL/min). INTERVENTIONS: Each patient consecutively received 4 hrs of placebo, followed by a 3 microg/kg/min dopamine infusion during 48 hrs, then a new 4-hr placebo period. We measured cardiac output and other hemodynamic variables by using a pulmonary artery catheter. The bladder was emptied to determine urine volume and to collect urine samples. Measurements were performed at six times: after the initial control of 4 hrs of placebo (C1); after 4 hrs (H4), 8 hrs (H8), 24 hrs (H24), and 48 hrs (H48) of dopamine infusion; and after the second control of 4 hrs of placebo (C2). MEASUREMENTS AND MAIN RESULTS: We saw no significant change in systemic hemodynamic variables with dopamine at all times of infusion. Diuresis, creatinine clearance, and the fractional excretion of sodium (FENa) at C1 and C2 were not different. Urine flow, creatinine clearance, and FENa increased significantly 4 hrs after starting dopamine (for all these changes, p < .01 vs. C1 and C2). The maximum changes were obtained at H8, with an increase of 50% for diuresis, 37% for creatinine clearance, and 85% for FENa (for all these changes, p < .01 vs. C1 and C2). But these effects waned progressively from H24, and both creatinine clearance and FENa at H48 did not differ from control values. CONCLUSIONS: In stable critically ill patients, preventive low-dose dopamine increased creatinine clearance, diuresis, and the fractional excretion of sodium without concomitant hemodynamic change. These effects reached a maximum during 8 hrs of dopamine infusion. But despite a slight persistent increase in diuresis, improvement in creatinine clearance and FENa disappeared after 48 hrs. According to these data, it is likely that tolerance develops to dopamine-receptor agonists in critically ill patients at risk of developing acute renal failure.

APACHE↗
PubMed1998

Bilateral continuous 3-in-1 nerve blockade for postoperative pain relief after bilateral femoral shaft surgery.

We tested the effectiveness of bilateral continuous paravascular femoral nerve blocks in a patient following bilateral femoral shaft surgery in whom other analgesic regimens were considered contraindicated or of limited effectiveness. Bilateral continuous femoral paravascular nerve blocks were performed using a previously described technique. General anesthesia was subsequently used to facilitate surgery, which was a bilateral osteosynthesis using dynamic hip screws for osteolytic metastases of the proximal extremities of both femurs. A continuous infusion of lidocaine, morphine, and clonidine was established in both femoral catheters preoperatively and used postoperatively as the principle source of analgesia. Radiographic contrast was used to document the position of both catheters and to document the spread of injectate. Visual analog scale (VAS) pain scores were recorded in the recovery room and at 4, 16, 24, 48, and 72 hours postoperatively. Plasma lidocaine levels were determined by gas chromatography at 4, 16, and 48 hours postoperatively. Sensory assessment in the distribution of the femoral, lateral cutaneous, and obturator nerves was performed to confirm the presence of sensory blockade. We successfully provided analgesia with bilateral continuous femoral paravascular nerve blocks. Pain scores at rest were consistently rated good to excellent (VAS < 20 mm). Evidence of sensory conduction block was present throughout the infusion. Plasma concentrations of lidocaine were consistently below toxic levels (1.35 to 1.65 micrograms/ml). Radiographic contrast studies failed to demonstrate movement of contrast to the level of the lumbar plexus. Bilateral continuous femoral paravascular nerve blocks can be used to provide effective and safe analgesia in patients requiring aggressive analgesia in whom other techniques may be contraindicated.

Anesthetics, Local↗
PubMed1998

Comparison of the three-in-one and fascia iliaca compartment blocks in adults: clinical and radiographic analysis.

UNLABELLED: The 3-in-1 (Group 1) and fascia iliaca compartment (Group 2) blocks, two single-injection, anterior approach procedures used to simultaneously block the femoral, obturator, and lateral femoral cutaneous (LFC) nerves, were compared in 100 adults after lower limb surgery. Pain control, sensory and motor blockades, and radiographically visualized spread of local anesthetic solution were studied prospectively. Both approaches provided efficient pain control using 30 mL of 2% lidocaine with 1:200,000 epinephrine and 0.5% bupivacaine and 5 mL of contrast media (iopamidol). Complete lumbar plexus blockade was achieved in 18 (38%) Group 1 and 17 (34%) Group 2 patients (n = 50 patients per group). Sensory block of the femoral, obturator, genitofemoral, and LFC nerves was obtained in 90% and 88%, 52% and 38%, 38% and 34%, and 62% and 90% of the patients in Groups 1 and 2, respectively (P < 0.05). Sensory LFC blockade was obtained more rapidly for the patients in Group 2 (P < 0.05). Concurrent internal and external spread of the local anesthetic solution under the fascia iliaca and between the iliacus and psoas muscles was noted in 62 of the 92 block procedures analyzed radiographically. Isolated external spreads under the fascia iliaca and over the iliacus muscle were noted in 10% and 36% of the patients in Groups 1 and 2, respectively (P < 0.05). The local anesthetic solution reached the lumbar plexus in only five radiographs. We conclude that the fascia iliaca compartment block is more effective than the 3-in-1 block in producing simultaneous blockade of the LFC and femoral nerves in adults. After both procedures, blockade was obtained primarily by the spread of local anesthetic under the fascia iliaca and only rarely by contact with the lumbar plexus. IMPLICATIONS: In adults, the two anterior approaches, 3-in-1 and fascia iliaca compartment blocks, provide effective postoperative analgesia. The fascia iliaca compartment technique provides faster and more consistent simultaneous blockade of the lateral femoral cutaneous and femoral nerves. Sensory block is caused by the spread of local anesthetic solution under the fascia iliaca and only rarely to the lumbar plexus.

Adult↗
PubMed1997

[Primary Vibrio vulnificus septicemia. 1st documented case in the French West Indies].

BACKGROUND: Vibrio vulnificus is a non-choleric halophilic vibrion widely distributed in marine environments. Contamination in humans is uncommon except in coastal areas of the United States and Asia. We report the first documented case in the French West Indies. CASE REPORT: A 57-year-old native with alcoholic cirrhosis was hospitalized for septic shock. The infectious syndrome began suddenly a few hours earlier with fever, diarrhea, and intense pain in the calf muscles. In the absence of a suspected agent, a wide spectrum antibiotic was prescribed. On day 3, bullae developed over the legs and progressed, despite early surgical debridement, to bilateral rapidly extensive necrosing cellulitis. An above the knee amputation was required but did not prevent death on day 9 due to irreversible multiple organ failure. Blood cultures were positive for V. vulnificus. DISCUSSION: Primary septicemia due to V. vulnificus is mainly observed in subjects with an underlying liver disease and usually occurs after ingestion of contamined raw halieutic products such as oysters. The clinical presentation is characteristic with secondary necrotic ulcerations on the lower limbs. Improvement in the extremely poor prognosis of these infections depends on early initiation of an effective antibiotic with wide exeresis of necrotic tissue. Physicians should be aware of this severe infection despite its low frequency.

Bacteremia↗