Biomedical subjects

Jean-François Menard

Publications and source records attributed to Jean-François Menard.

4 recordsLinked to original sources

PubMed2006

Comparative effects of ivabradine, a selective heart rate-lowering agent, and propranolol on systemic and cardiac haemodynamics at rest and during exercise.

AIM: To compare in humans the effects of ivabradine and propranolol on cardiac and systemic haemodynamics at rest, during tilt and exercise. METHODS: Nine healthy volunteers randomly received single oral doses of ivabradine (Iva, 30 mg), propranolol (Propra, 40 mg) or placebo (Plac) during a double-blind cross-over study. Doses were selected to be equipotent in heart rate (HR) reduction. HR, systolic and diastolic blood pressure (SBP, DBP), cardiac index (CI, bioimpedance), rate pressure product (RPP), plasma epinephrine (E) and norepinephrine (NE), were measured at rest at baseline, before and after two tilt and exercise tests, started 2 and 5 h after drug intake. Heart rate variability (low to high frequency ratio LF/HF) was evaluated at rest and at 5 th minute of tilt. RESULTS: At rest, HR and RPP decreased similarly with Iva and Propra (both P < 0.01). During tilt, HR increased less with Iva than Propra (P < 0.01), LF/HF decreased after Iva (P < 0.03), SBP and mean blood pressure decreased after Propra (both P < 0.01), RPP decreased similarly after Iva and Propra (both P < 0.01) and CI decreased to a greater extent with Propra than with Iva or Plac (both P < 0.04). During exercise, Iva and Propra similarly decreased HR (both P < 0.01) and RPP (P < 0.01). CONCLUSIONS: These results demonstrate that for a similar decrease in HR at rest and during sympathetic stimulation, acute administration of ivabradine, a selective heart rate-lowering agent, decreased myocardial oxygen demand to the same extent as a reference beta-blocker, propranolol, but without evidence of depressant effect on cardiac function.

Adolescent↗

PubMed2005

Predictive visual outcome after macula-off retinal detachment surgery using optical coherence tomography.

PURPOSE: To determine whether preoperative optical coherence tomography (OCT) is useful in predicting postoperative visual outcome for patients with primary macula-off rhegmatogenous retinal detachment (RD). METHODS: This prospective study included 20 nonconsecutive eyes with macula-off RD and successful reattachment of the retina. Preoperative 5-mm OCT was performed through the center of the fovea. The relationship among preoperative OCT findings, main preoperative clinical variables, and final postoperative visual acuity was statistically analyzed. RESULTS: Final postoperative visual acuity was negatively correlated with three preoperative OCT variables: height of RD at the central fovea (r=0.79; P <0.001), distance from the central fovea to the nearest undetached retina (r=0.75; P <0.00051), and, to a lesser degree, extent of structural changes in the detached retina (r=0.48; P=0.03). Preoperative visual acuity was the only clinical variable statistically correlated with final postoperative visual acuity in this study (r=0.55; P=0.01). Using multivariate logistic regression analyses, the structure of the detached retina combined with the distance from the central fovea to the nearest undetached retina, as determined with OCT, was highly correlated with final postoperative visual acuity (r=0.82; P <0.000051). CONCLUSION: Preoperative macular analysis with OCT may help to predict visual outcome for patients with macula-off RD.

Adult↗

PubMed2004

Erythropoietin and renin as biological markers in critically ill patients.

INTRODUCTION: During sepsis the endocrine, immune and nervous systems elaborate a multitude of biological responses. Little is known regarding the mechanisms responsible for the final circulating erythropoietin (EPO) and renin levels in septic shock. The aim of the present study was to assess the role of EPO and renin as biological markers in patients with septic shock. METHODS: A total of 44 critically ill patients with septic shock were evaluated. RESULTS: Nonsurvivors had significantly higher serum EPO levels than did survivors on admission (median [minimum-maximum]; 61 [10-602] versus 20 [5-369]). A negative relationship between serum EPO and blood haemoglobin concentrations was observed in the survivor group (r = -0.61; P < 0.001). In contrast, in the nonsurvivors the serum EPO concentration was independent of the blood haemoglobin concentration. Furthermore, we observed significant relationships between EPO concentration and lactate (r = 0.5; P < 0.001), arterial oxygen tension/fractional inspired oxygen ratio (r = -0.41; P < 0.005), arterial pH (r = -0.58; P < 0.001) and renin concentration (r = 0.42; P < 0.005). With regard to renin concentration, significant correlations with lactate (r = 0.52; P < 0.001) and arterial pH (r = -0.33; P < 0.05) were observed. CONCLUSION: Our findings show that EPO and renin concentrations increased in patients admitted to the intensive care unit with septic shock. Renin may be a significant mediator of EPO upregulation in patients with septic shock. Further studies regarding the regulation of EPO expression are clearly warranted.

Aged↗

PubMed2003

Gastric mucosal acidosis and cytokine release in patients with septic shock.

OBJECTIVE: It has been postulated that in critically ill patients, splanchnic hypoperfusion may lead to cytokine release into the systemic circulation. The presence of cytokines could trigger an inflammatory response and cause multiple organ dysfunction syndrome. Although experimental studies support this hypothesis, humans studies remain controversial. The aim of the study was to determine the relationship between splanchnic hypoperfusion and cytokine release during septic shock. DESIGN: Human prospective study. SETTING: Medical intensive care unit at a university hospital. PATIENTS: A total of 30 patients with mean arterial pressure of <60 mm Hg after volume loading with either oliguria or hyperlactatemia. MEASUREMENTS: Gastric intramucosal measurements as an indicator of splanchnic hypoperfusion and blood samples were obtained at admission to the medical intensive care unit and repeated during 48 hrs. Cytokine (tumor necrosis factor-alpha and interleukin-6) values were evaluated by enzyme-linked immunoassays at the following periods: at the time of admission and 2, 4, 8, 12, 24, 36, and 48 hrs later. MAIN RESULTS: High levels of interleukin-6 and tumor necrosis factor-alpha were observed at admission in survivors and nonsurvivors, without significant difference. At 48 hrs, cytokine levels were significantly higher in patients who died compared with the survivors (tumor necrosis factor: 163 +/- 16 for nonsurvivors vs. 34 +/- 9 ng/mL for survivors; interleukin-6: 2814 +/- 485 for nonsurvivors vs. 469 +/- 107 ng/mL for survivors). At 48 hrs, the PCO2 gap was significantly higher in the nonsurvivors compared with survivors (25.87 +/- 2.73 vs. 11.35 +/- 2.25 mm Hg), despite systemic hemodynamic variables in the normal range. A positive relationship was demonstrated between plasma levels of tumor necrosis factor-alpha and interleukin-6 and the PCO2 gap throughout the study. The PCO2 gap was not correlated with hemodynamic variables. CONCLUSIONS: Our data suggest a relationship between gastric mucosal acidosis, as assessed by PCO2 gap, and cytokine levels in critically ill patients with septic shock. Gut injury may be a contributor of the inflammatory response in patients with septic shock.

APACHE↗