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Biomedical subjects

Christian Richard

Publications and source records attributed to Christian Richard.

At least 37 records · Page 2Linked to original sources
PubMed2005

Esophageal Doppler monitoring predicts fluid responsiveness in critically ill ventilated patients.

OBJECTIVE: To test whether fluid responsiveness can be predicted by the respiratory variation in aortic blood flow and/or the flow time corrected for heart rate monitored with esophageal Doppler. DESIGN AND SETTING: Prospective study in a 24-bed medical intensive care unit of a university hospital. PATIENTS: 38 mechanically ventilated patients with sinus rhythm and without spontaneous breathing activity in whom volume expansion was planned. INTERVENTIONS: The aortic blood flow was measured using an esophageal Doppler monitoring device before and after fluid infusion (500 ml NaCl 0.9% over 10 min). The variation in aortic blood flow over a respiratory cycle between its minimal and maximal values was calculated. The flow time was also measured. MEASUREMENTS AND RESULTS: Aortic blood flow increased by at least 15% after volume expansion in 20 patients (defined as responders). Before fluid infusion the respiratory variation in aortic flow was higher in responders than in nonresponders (28+/-12% vs. 12+/-5%). It significantly decreased after volume expansion (18+/-11%) in responders only. A respiratory variation in aortic flow before volume expansion of at least 18% predicted fluid responsiveness with a sensitivity of 90% and a specificity of 94%. Flow time increased with fluid infusion in responders and nonresponders. A flow time corrected for heart rate below 277 ms predicted fluid responsiveness with a sensitivity of 55% and a specificity of 94%. The area under the ROC curve generated for variation in aortic blood flow ABF was greater than that generated for flow time. CONCLUSIONS: The respiratory variation in aortic blood flow reliably predicts fluid responsiveness in patients with sinus rhythm and without breathing activity.

Aorta↗
PubMed2005

[Shock].

Explore the source record for details and available documents.

Diagnosis, Differential↗
PubMed2004

Expression and activity of steroid aldoketoreductases 1C in omental adipose tissue are positive correlates of adiposity in women.

We examined expression and activity of steroid aldoketoreductase (AKR) 1C enzymes in adipose tissue in women. AKR1C1 (20alpha-hydroxysteroid dehydrogenase; 20alpha-HSD), AKR1C2 (3alpha-HSD-3), and AKR1C3 (17beta-HSD-5) are involved mainly in conversion of progesterone to 20alpha-hydroxyprogesterone and inactivation of dihydrotestosterone to 5alpha-androstane-3alpha,17beta-diol. Abdominal subcutaneous and omental adipose tissue biopsies were obtained during abdominal hysterectomies in seven women with low visceral adipose tissue (VAT) area and seven age- and total body fat mass-matched women with visceral obesity. Women with elevated VAT areas were characterized by significantly higher omental adipose tissue 20alpha-HSD and 3alpha-HSD-3 mRNA abundance compared with women with low VAT accumulations (1.4- and 1.6-fold differences, respectively; P < 0.05). Omental and subcutaneous adipose tissue 3alpha-HSD activities were significantly higher in women with high vs. low VAT areas (P < 0.05 for both comparisons). Total and visceral adiposities were positively associated with omental 20alpha-HSD mRNA level (r = 0.75, P < 0.003 for fat mass; r = 0.57, P < 0.04 for VAT area) and omental 3alpha-HSD-3 mRNA level (r = 0.68, P < 0.01 for fat mass; r = 0.74, P < 0.003 for VAT area). Enzyme activities in both depots were also positively correlated with adiposity measures. Omental adipose tissue enzyme expression and activity were positively associated with omental adipocyte size and LPL activity. In conclusion, mRNA abundance and activity of AKR1C enzymes in abdominal adipose tissue compartments are positive correlates of adiposity in women. Increased progesterone and/or dihydrotestosterone reduction in abdominal adipose tissue may impact locally on fat cell metabolism.

20-Hydroxysteroid Dehydrogenases↗
PubMed2004

Expression and activity of 20alpha-hydroxysteroid dehydrogenase (AKR1C1) in abdominal subcutaneous and omental adipose tissue in women.

We examined the expression and activity of 20alpha-hydroxysteroid dehydrogenase (20alpha-HSD) in abdominal adipose tissue in women. This recently characterized enzyme from the aldoketoreductase 1C family is responsible for the conversion of progesterone into 20alpha-hydroxyprogesterone. Abdominal sc (SC) and omental (OM) adipose tissue biopsies were obtained from a sample of 32 women aged 47.7 +/- 5.9 yr (body mass index 27.6 +/- 5.0 kg/m(2)) undergoing abdominal hysterectomies. Body composition and body fat distribution measurements were performed before the surgery by dual-energy x-ray absorptiometry and computed tomography, respectively. The expression of 20alpha-HSD was determined by real-time RT-PCR, and its activity was measured in whole-tissue homogenates. mRNA and activity of the enzyme were detected in both the SC and OM fat depots, the two measures being significantly higher in the SC compartment. Women characterized by a visceral adipose tissue area of 100 cm(2) or greater had an increased 20alpha-HSD conversion rate in their OM adipose tissue, compared with women without visceral obesity (13.99 +/- 2.07 vs. 7.92 +/- 0.83 fmol/microg protein per 24 h, P < 0.05). Accordingly, a positive correlation was found between OM adipose tissue 20alpha-HSD activity and computed tomography-measured visceral adipose tissue area (r = 0.36, P < 0.05). Significant positive correlations were also found between OM 20alpha-HSD activity and OM adipocyte diameter (r = 0.49, P < 0.05) and OM adipose tissue LPL activity (r = 0.36, P = 0.06). In conclusion, 20alpha-HSD activity and mRNA were detected in SC and OM adipose tissue in women, and OM 20alpha-hydroxylation of progesterone was highest in women with visceral obesity. Additional studies are required to establish whether local conversion of progesterone may impact on the metabolism and function of adipocytes located within the abdominal cavity.

20-Hydroxysteroid Dehydrogenases↗
PubMed2004

Ovarian hormone status and abdominal visceral adipose tissue metabolism.

We examined abdominal sc and visceral adipose tissue metabolism in a sample of 19 regularly cycling premenopausal women (age 46.3 +/- 3.7 yr) and 10 women with natural menopause or pharmacological ovarian suppression (age 51.1 +/- 9.2 yr). Subcutaneous and visceral (omental, epiploic) adipose tissue biopsies were obtained during abdominal hysterectomies. Body composition and adipose tissue distribution were measured before the surgery by dual x-ray absorptiometry and computed tomography, respectively. Ovarian hormone-deficient women tended to be older (P = 0.08) and were characterized by increased visceral adipose tissue area (P < 0.05). Subcutaneous adipocyte size, lipoprotein lipase (LPL) activity, and basal lipolysis were not significantly different between groups. On the other hand, omental fat cell size was significantly higher in ovarian hormone-deficient women, compared with premenopausal women (P < 0.05). The omental/sc LPL activity ratio and omental adipocyte basal lipolysis were also significantly higher in ovarian hormone-deficient women (P < 0.05 for both comparisons). Significant positive correlations were found between visceral adipose tissue area and omental LPL activity (r = 0.54, P < 0.003), omental adipocyte basal lipolysis (r = 0.66, P < 0.0001), and omental fat cell size (r = 0.81, P < 0.0001). In multivariate analyses, ovarian status was no longer a significant predictor of adipose cell metabolism variables after visceral adipose tissue area was entered into the model, with the exception of the omental/sc LPL activity ratio, which remained independently associated with ovarian status. In conclusion, although the size of the visceral adipose tissue compartment was an important determinant of adipocyte metabolism in this depot, the increased omental/sc LPL activity ratio in ovarian hormone-deficient women supports the notion of a predominant visceral fat storage in these women.

Abdomen↗
PubMed2003

Early use of the pulmonary artery catheter and outcomes in patients with shock and acute respiratory distress syndrome: a randomized controlled trial.

CONTEXT: Many physicians believe that the pulmonary artery catheter (PAC) is useful for the diagnosis and treatment of cardiopulmonary disturbances; however, observational studies suggest that its use may be harmful. OBJECTIVE: To determine the effects on outcome of the early use of a PAC in patients with shock mainly of septic origin, acute respiratory distress syndrome (ARDS), or both. DESIGN, SETTING, AND PATIENTS: A multicenter randomized controlled study of 676 patients aged 18 years or older who fulfilled the standard criteria for shock, ARDS, or both conducted in 36 intensive care units in France from January 30, 1999, to June 29, 2001. INTERVENTION: Patients were randomly assigned to either receive a PAC (n = 335) or not (n = 341). The treatment was left to the discretion of each individual physician. MAIN OUTCOME MEASURES: The primary end point was mortality at 28 days. The principal secondary end points were day 14 and 90 mortality; day 14 organ system, renal support, and vasoactive agents-free days; hospital, intensive care unit, and mechanical ventilation-free days at day 28. RESULTS: The 2 groups were similar at baseline. There were no significant differences in mortality with or without the PAC at day 14: 49.9% vs 51.3% (mortality relative risk [RR], 0.97; 95% confidence interval [CI], 0.84-1.13; P =.70); day 28: 59.4% vs 61.0% (RR, 0.97; 95% CI, 0.86-1.10; P =.67); or day 90: 70.7% vs 72.0% (RR, 0.98; 95% CI, 0.89-1.08; P =.71). At day 14, the mean (SD) number of days free of organ system failures with or without the PAC (2.3 [3.6] vs 2.4 [3.5]), renal support (7.4 [6.0] vs 7.5 [5.9]), and vasoactive agents (3.8 [4.8] vs 3.9 [4.9]) did not differ. At day 28, mean (SD) days in hospital with or without the PAC (0.9 [3.6] vs 0.9 [3.3]), in the intensive care unit (3.4 [6.8] vs 3.3 [6.9]), or mechanical ventilation use (5.2 [8.5] vs 5.0 [8.5]) did not differ. CONCLUSION: Clinical management involving the early use of a PAC in patients with shock, ARDS, or both did not significantly affect mortality and morbidity.

Adult↗
PubMed2003

The impact of hands-free message reception/response on driving task performance.

A series of closed-course driving experiments were conducted in which 41 drivers ranging in age from 19 to 70 were put through a series of increasingly challenging driving performance tasks both in the presence and absence of audible messages. The messages required specific responses and these, along with driving performance measures based on driver/vehicle response characteristics, were recorded. The results clearly showed a negative impact of the message task on driver decision-making performance when this involved the more complex tasks of weaving and especially left-turning. Such decision-making decrements in the presence of the messages were exacerbated by adverse pavement surface conditions.

Adult↗
PubMed2003

Helium/oxygen mixture reduces the work of breathing at the end of the weaning process in patients with severe chronic obstructive pulmonary disease.

OBJECTIVE: To test the hypothesis that helium/oxygen mixture can reduce the work of breathing at the end of the weaning process in patients with chronic obstructive pulmonary disease. DESIGN: Prospective, randomized, crossover study. SETTING: Two medical intensive care units at two university tertiary care centers. PATIENTS: Thirteen patients with chronic obstructive pulmonary disease evaluated just before and after extubation. INTERVENTIONS: Helium/oxygen and air/oxygen mixtures were administered sequentially, for 20 mins each, in a randomized order, just before extubation. It was possible to repeat the study after extubation in five patients. MEASUREMENTS AND MAIN RESULTS: Before extubation, the helium/oxygen mixture induced no significant variation in the breathing pattern. By contrast, it reduced the work of breathing from 1.442 +/- 0.718 J/L (mean +/- sd) to 1.133 +/- 0.500 J/L (p <.05). This reduction was explained mainly by a reduction in the resistive component of the work of breathing from 0.662 +/- 0.376 to 0.459 +/- 0.256 J/L (p <.01). We also observed a slight reduction in the intrinsic positive end-expiratory pressure from 2.9 +/- 2.1 cm H(2)O to 2.1 +/- 1.8 cm H(2)O (p <.05). Similar results were also observed after extubation in five patients in whom the repetition of the study was possible. CONCLUSIONS: In spontaneously breathing intubated patients with chronic obstructive pulmonary disease recovering from an acute exacerbation, helium/oxygen mixture reduces the work of breathing as well as intrinsic positive end-expiratory pressure without modifying the breathing pattern.

Acute Disease↗
PubMed2003

Local androgen inactivation in abdominal visceral adipose tissue.

We examined the expression and activity of two enzymes from the aldoketoreductase (AKR) family 1C, namely type 5 17beta-hydroxysteroid dehydrogenase (17beta-HSD-5, AKR1C3) and type 3 3alpha-hydroxysteroid dehydrogenase (3alpha-HSD-3, AKR1C2) in female sc and omental adipose tissue and in preadipocyte primary cultures. 17beta-HSD-5 preferentially synthesizes testosterone from the inactive adrenal precursor androstenedione, whereas 3alpha-HSD-3 inactivates dihydrotestosterone. mRNAs of both enzymes were detected in adipose tissue from the omental and sc compartments. Real-time PCR quantification indicated a 3-fold higher 3alpha-HSD-3 expression compared with 17beta-HSD-5, and the expression of both enzymes tended to be higher in the sc vs. the omental depot. Accordingly, dose-response and time-course experiments performed in preadipocyte primary cultures indicated that 3alpha-HSD activity was higher than 17beta-HSD activity (13-fold maximum velocity difference). We measured 3alpha-HSD activity in omental and sc adipose tissue samples of 32 women for whom body composition and body fat distribution were evaluated by dual-energy x-ray absorptiometry and CT, respectively. We found that androgen inactivation in omental adipose tissue through 3alpha-HSD activity was significantly higher in women with elevated vs. low visceral adipose tissue accumulation (1.7-fold difference; P < 0.05). Moreover, omental adipose tissue 3alpha-HSD activity was positively and significantly associated with CT-measured visceral adipose tissue (r = 0.43; P < 0.02) and omental adipocyte diameter (r = 0.42; P < 0.02). These results indicate that local androgen inactivation is a predominant reaction in female abdominal adipose tissue, with the greatest conversion rates observed in the presence of abdominal visceral obesity. Increased androgen inactivation in omental adipose tissue of abdominally obese women may impact locally on the regulation of adipocyte metabolism.

17-Hydroxysteroid Dehydrogenases↗
PubMed2003

Global end-diastolic volume as an indicator of cardiac preload in patients with septic shock.

STUDY OBJECTIVE: To assess the value of the global end-diastolic volume (GEDV) evaluated by transpulmonary thermodilution as an indicator of cardiac preload. DESIGN: Prospective clinical study. SETTING: Medical ICU of a university hospital (20 beds). PATIENTS: Thirty-six patients with septic shock. INTERVENTIONS: Volume loading and dobutamine infusion. MEASUREMENTS AND RESULTS: Hemodynamic parameters were evaluated in triplicate by the transpulmonary thermodilution technique: (1) before and after 66 fluid challenges in 27 patients, and (2) before and after 28 increases in dobutamine infusion rate in 9 patients. Volume loading induced a significant (p < 0.001) increase in central venous pressure (CVP) from 10 +/- 4 to 13 +/- 4 mm Hg, in GEDV index from 711 +/- 164 to 769 +/- 144 mL/m(2), in stroke volume index (SVI) from 36 +/- 12 to 42 +/- 12 mL/m(2), and in cardiac index (CI) from 3.4 +/- 1.1 to 3.9 +/- 1.2 L/min/m(2) (mean +/- SD). Changes in GEDV index were correlated (r = 0.72, p < 0.001) with changes in SVI, while changes in CVP were not. The increase in SVI was > 15% in 32 of 66 instances (positive response). The preinfusion GEDV index was lower (637 +/- 134 mL/m(2) vs 781 +/- 161 mL/m(2), p < 0.001) in the cases of positive response, and was negatively correlated with the percentage increase in GEDV index (r = - 0.65, p < 0.001) and in SVI (r = - 0.5, p < 0.001). Dobutamine infusion induced an increase in SVI (32 +/- 11 mL/m(2) vs 35 +/- 12 mL/m(2), p < 0.05) and in CI (2.8 +/- 0.6 L/min/m(2) vs 3.2 +/- 0.6 L/min/m(2), p < 0.001) but no significant change in CVP (13 +/- 3 mm Hg vs 13 +/- 3 mm Hg) and in GEDV index (823 +/- 221 mL/m(2) vs 817 +/- 202 mL/m(2)). CONCLUSION: In patients with septic shock, our findings demonstrate that, in contrast to CVP, the transpulmonary thermodilution GEDV index behaves as an indicator of cardiac preload.

Adult↗