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Biomedical subjects

F Molenat

Publications and source records attributed to F Molenat.

14 recordsLinked to original sources
PubMed2000

Ascent rate and circulating venous bubbles in recreational diving.

The aim of this study was to assess the effect of the ascent rate on the production of venous circulating bubbles during the decompression following a recreational dive. Twenty-eight recreational divers performed two open water dives at 35 m during 25 minutes. Ascent rate up to the decompression stop was in one case 9 meter per minute (m/min) and in the other case 17 m/min. Circulating venous bubbles were screened using continuous wave Doppler every 10 minutes during one hour after surfacing. Bubbles Doppler signals were graded according to the Spencer scale (from 0 to IV), and the Kisman integrated severity score (KISS) was calculated. Statistical analysis demonstrated a significantly higher bubbles grade and a significantly higher KISS following the rapid decompression compared to the slow one (respectively p = 0.001 and p = 0.0001). In conclusion, these results demonstrate that a 9 m/min ascent rate is safer than a 17 m/min one.

Adult↗
PubMed2000

Operation Everest III (Comex '97): modifications of cardiac function secondary to altitude-induced hypoxia. An echocardiographic and Doppler study.

During Operation Everest III (Comex '97), to assess the consequences of altitude-induced hypoxia, eight volunteers were decompressed in a hypobaric chamber, with a decompression profile simulating the climb of Mount Everest. Cardiac function was assessed using a combination of M-mode and two-dimensional echocardiography, with continuous and pulsed Doppler at 5,000, 7,000, and 8,000 m as well as 2 d after return to sea level (RSL). On simulated ascent to altitude, aortic and left atrial diameters, left ventricular (LV) diameters, and right ventricular (RV) end-systolic diameter fell regularly. Heart rate (HR) increased at all altitudes accompanied by a decrease in stroke volume; in total, cardiac output (Q) remained unchanged. LV filling was assessed on transmitral and pulmonary venous flow profiles. Mitral peak E velocity decreased, peak A velocity increased, and E/A ratio decreased. Pulmonary venous flow velocities showed a decreased peak D velocity, a decreased peak S velocity, and a reduction of the D/S ratio. Systolic pulmonary arterial pressure (Ppa) showed a progressive and constant increase, as seen on the elevation of the right ventricular/right atrial (RV/RA) gradient pressure from 19.0 +/- 2.4 mm Hg at sea level up to 40.1 +/- 3.3 mm Hg at 8,000 m (p < 0.05), and remained elevated 2 d after recompression to sea level (SL) (not significant). In conclusion, this study confirmed the elevation of pulmonary pressures and the preservation of LV contractility secondary to altitude-induced hypoxia. It demonstrated a modification of the LV filling pattern, with a decreased early filling and a greater contribution of the atrial contraction, without elevation of LV end-diastolic pressure.

Adult↗
PubMed2000

Left atrial and ventricular filling in chronic obstructive pulmonary disease. An echocardiographic and Doppler study.

Abnormal left ventricular (LV) diastolic function has frequently been reported in patients with chronic obstructive pulmonary disease (COPD). In the present work, diastolic function was studied by a combined analysis of pulmonary venous and mitral blood flow velocities in 34 patients with COPD clinically stable and without history of heart disease, and 20 control subjects. We confirmed the increased contribution of the atrial contraction to the LV filling in COPD patients in comparison with control subjects; furthermore, a decreased left atrial (LA) filling during the ventricular systole was observed. Changes in LV filling were not the consequence of a systolic dysfunction, because LV systolic function was normal. Doppler indices indicated that LA pressure was below 15 cm H(2)O in all the patients with COPD and control subjects. Several factors can be put forward to explain these changes; the first one is tachycardia. In addition to hypoxemia and medications, echocardiography suggested that a decreased LV preload participated in increased heart rate. Analysis of Doppler transmitral and pulmonary venous flows demonstrated the role of the ventricular interdependence because a correlation existed between LA and LV filling pattern and right ventricle pressure and diameter.

Atrial Function, Left↗
PubMed1999

A new simple method to perform pressure-volume curves obtained under quasi-static conditions during mechanical ventilation.

OBJECTIVE: To describe a fast, simple method to acquire pressure-volume curves of the respiratory system and to compare this with a classic method in terms of reliability of the data and speed. DESIGN: Acquisition of pressure-volume curves by low flow inflation technique (P-Vlf) versus the occlusion technique (P-Vst) using the standard equipment of a Cesar ventilator. SETTING: General ICU - Aix en Provence Hospital. PATIENTS: Ten sedated, curarized patients undergoing mechanical ventilation. INTERVENTIONS: P-Vlf curves were acquired by setting the ventilator parameters at f = 5 c./min, duty time Ti/Ttot = 80 %, VT = 1100 ml, pause time = 0. The pressure and volume data were collected directly on the ventilator screen. P-Vst curves were acquired using an airway occlusion technique. The pressures obtained for the same inflation volumes and times necessary for performance of the two techniques were compared. RESULTS: The time needed to acquire a P-Vlf curve was 3 min versus 38 min for P-Vst curve. Concordance analysis between the two methods showed a 95 % confidence interval of (-0.5 cm H2O, + 1.8 cm H2O) for pressure. CONCLUSIONS: P-Vlf curves are close to P-Vst curves, are much less time-consuming, easy to acquire with Cesar ventilator equipment, and may be used in clinical routine to assess the elastic properties of the respiratory system.

Adult↗
PubMed1999

Venous gas embolism: detection with pulsed Doppler guided by two-dimensional echocardiography.

BACKGROUND: Venous gas embolism is a rare but severe event in critically ill patients and the diagnosis should be obtained as soon as possible. Ultrasonography is a sensitive, non-invasive, and bedside means of detection. METHOD: We prospectively estimated the performance of two-dimensional (2D) echocardiography and pulsed Doppler guided by 2D echocardiography in the detection of venous embolism. We used, as a model of venous gas embolism, the decompression following a recreational dive. This activity is responsible for circulating bubbles related to nitrogen desaturation. RESULTS: Venous gas emboli were detected following 44 of 68 dives in 20 of 24 divers. Gas emboli in 36 cases (16 divers) was shown by 2D echocardiography. Parasternal short-axis and right-cavity longitudinal views were the best views for positive detection. Pulsed Doppler confirmed the existence of venous gas emboli in all of the 36 cases with positive detection by 2D echocardiography. In 8 other cases, pulsed Doppler detected circulating bubbles, which were not observed by using 2D echocardiography. Discrepancies were observed in 4 divers with an echographic image of medium or poor quality. CONCLUSION: Combined utilization of 2D echocardiography and pulsed Doppler provides a better method for the detection of venous gas embolism than 2D echocardiography alone. This protocol could be used for critically ill patients suspected of venous air embolism.

Adult↗
PubMed1998

Diagnosis of nosocomial pneumonia in mechanically ventilated patients: repeatability of the bronchoalveolar lavage.

The repeatability of the bronchoalveolar lavage (BAL) was assessed prospectively in 44 mechanically ventilated patients with suspected nosocomial pneumonia. Two BAL were performed in the same lung area (contiguous segment) during two fibroscopic procedures performed with a thirty minute interval. All the bronchoscopies were performed by the same operator. The statistical analysis looked out for bias (MacNemar test), agreement, and repeatability (kappa test). In the 44 patients studied, the qualitative repeatability (i.e., presence or absence of bacteria) was excellent (95.4%). However, in the 16 patients having at least one positive culture, these results were more controversial. The quantitative repeatability for bacteria (same log10 for both BAL of the same patient) was the lowest of all the results (26.7%). The distinction between presence and absence of bacterial pneumonia (based on the 10[4] cfu/ml threshold) showed a repeatability of 75% with no bias, an agreement of 47% and a just-significant kappa test (test = 1.97; p = 1.96 for a 5% risk error). BAL seems to have excellent repeatability when sterile. Its repeatability when positive needs further studies to be assessed.

Adult↗
PubMed1996

Gallbladder abnormalities in medical ICU patients: an ultrasonographic study.

Patients in the intensive care unit (ICU) have many risks factors for gallbladder stasis or acute acalculous cholecystitis (ACC), including fasting, total parenteral nutrition, sedation, mechanical ventilation, infection and shock. We have performed a prospective study to estimate the prevalence of ultrasonographic gallbladder abnormalities in 30 consecutive medical ICU patients during the first 2 days of their stay in the ICU. Two patients had previously undergone cholecystectomy and were excluded from the study. Seventeen (61%) of the remaining 28 patients presented with gallbladder abnormalities. Considering three major criteria of ACC, 14 patients (50%) presented with either sludge (25%), wall thickening (22%) or hydrops (11%). However, none of the patients needed a surgical procedure during the study because of gallbladder disease. We conclude that an important proportion of ICU patients presented with gallbladder abnormalities shown by ultrasonography and that this may have implications for establishing a diagnosis of ACC using ultrasonographic criteria.

Female↗
PubMed1996

Haemoconcentration in neurological decompression illness.

Decompression illness (DCI) is attributed to the formation of bubbles, resulting from the reduction of the ambient pressure. Circulating bubbles lead to capillary leak syndrome, extravasation of plasma and haemoconcentration. Experimental model on animals has shown that a haemoconcentration carried a poor prognosis. We measured the haematocrit level in fifty-eight consecutive sport divers, victims of neurological DCI, admitted to our hyperbaric center, and in sixteen control divers. No significant difference was found in the haematocrit values between the divers with neurological DCI (median 42.5%) and the controls (median 41.75%). The median haematocrit level was significantly higher for divers with neurological sequelae when compared with control (p = 0.01) or with divers without sequelae (p < 0.05). A haematocrit level > or = 48% was correlated with persistent neurological sequelae one month after the accident (p = 0.01). However, a haematocrit < 48% had no prognostic value.

Adult↗
PubMed1996

Neurologic decompression illness: a gravity score.

Treatment of neurologic decompression accidents consists of various hyperbaric oxygen (HBO) protocols. To facilitate such comparisons between different protocols we developed a gravity score. A group of 96 divers was used to establish the score. On admission we first identified signs and symptoms that had possible predictive value (chi 2 test). The parameters included were repetitive dive, clinical course before HBO, objective sensory disorder, motor impairment, and urinary disturbances. Each parameter was assigned a coefficient. The sum of the coefficients for each accident, based on the most severe manifestations before decompression therapy, yielded a score for each diver. A multivariate analysis was used to evaluate the overall agreement between the model prediction and clinical observations, which was 78.7%. A second group (66 divers) was used to validate the score; this group showed a significant difference in the gravity score between the divers who had sequelae and those who did not (P = 0.0001), and between the divers who had incapacitating sequelae and those who had mild sequelae (P = 0.04). Eighty-six percent of the divers with a score above 7 developed sequelae. This index remains to be validated in a prospective multicenter study. If endorsed, valid comparisons can be made between the different therapeutic protocols.

Adult↗
PubMed1995

[Prognosis in iatrogenic gas embolism].

Prognosis of iatrogenic air embolism is various according to previous studies. The purpose of this study was to determine the risks factors associated with the prognosis of iatrogenic air embolism. We conducted a retrospective analysis of 113 patients treated with HBO therapy in our hyperbaric center from 1979 to 1993. Initial symptomatology consisted in neurological disorders (71% of cases), respiratory disorders (43% of cases) and hemodynamic disorders (33% of cases). When neurological disorders were observed, HBO therapy included immediate compression to 6 atm abs for 10 to 15 mn with air followed by decompression to 2 atm abs where the patients received 100% oxygen during 1 hour. When no neurological disorders was observed, HBO therapy consisted in an oxygenation for 1 h, 2 atm abs, FiO2 = 1. Overall outcome was: recovery: 69 per cent of cases, sequelae: 26 per cent of cases, death: 5 per cent of cases. Prognosis was very different according to etiologies and existence of neurological disorders. Venous emboli had a better improvement than arterial emboli. In conclusion, patterns of air embolism can be divided clinically into two major categories, cerebral and pulmonary air embolism, which should be individualised in clinical studies. The studies must also individualised etiologies.

Adolescent↗
PubMed1991

[Techniques, results and indications of embryonic reductions in multiple pregnancies. Review of the literature].

The authors report, after a review of the literature, the evolution of ideas concerning first-trimester terminations in multiple pregnancies. Different techniques are performed including transabdominal approach or transvaginal approach at the mean gestational age of 9 or 11 weeks of amenorrhea. Analysis of obstetrical results obtained after these procedures (rates of early or late abortions, preterm labor or in utero growth retardation) shows a high rate of abortions and demonstrate also that reductions are unable to prevent premature births. Indications are discussed: concerning pregnancies of high order (four or more), most part of authors agree with the procedure and also when a triplet pregnancy occurs on a scarred or malformed uterus. Concerning triplet pregnancies, the procedure remains considered by some teams as an unethical approach of theses gestations, specially when considering the recent advances in perinatal medicine. In all cases, a clear and complete information about the risks of these procedures should be given to couples faced with multiple pregnancies.

Abortion, Induced↗
PubMed1988

[Pregnancies occurring after a perinatal death. Preparation of a psychological risk index].

The authors have interviewed 21 women who were attending the gynaecological and obstetrical service of the hospital for pregnancies occurring after a perinatal death. They show that anxiety is characteristic of these situations, but that the intensity of anxiety varies from woman to woman. They describe, after analysing the interviews, the different variations that can be found as these pregnancies progress according to the type of anxiety. By using a statistical analysis they can separate out the most important criteria and they can work out a method of illustrating a threshold which can easily be used by obstetricians in everyday practice. They suggest a method of handling the patients according to the level of anxiety found.

Anxiety Disorders↗