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Biomedical subjects

F Lemaire

Publications and source records attributed to F Lemaire.

At least 91 records · Page 5Linked to original sources
PubMed1995

Frequency of bacteremia associated with transesophageal echocardiography in intensive care unit patients: a prospective study of 139 patients.

OBJECTIVE: To determine the occurrence rate of bacteremia associated with transesophageal echocardiography in intensive care unit (ICU) patients. DESIGN: A prospective study of 139 patients undergoing transesophageal echocardiography. SETTING: The medical ICU of a tertiary referral teaching hospital. PATIENTS: One hundred thirty-nine ICU patients (mean age 58 yrs) who underwent transesophageal echocardiography. INTERVENTIONS: Blood samples were systematically drawn for aerobic and anaerobic culture at the following times: before (blood culture 1), at the end of (blood culture 2), and 30 mins after (blood culture 3) transesophageal echocardiography examinations. MEASUREMENTS AND MAIN RESULTS: The mean duration of transesophageal echocardiography was 35 mins (range 7 to 120). One hundred thirty-four patients received mechanical ventilation; 125 patients had a nasogastric tube. Fifty-one patients had one or more underlying conditions that usually justify antimicrobial prophylaxis of bacterial endocarditis before high-risk procedures. Fifty-six patients did not receive any antibiotic treatment at the time of transesophageal echocardiography. In 114 patients, the three blood cultures were negative. In six patients, transesophageal echocardiography was performed during a preexisting bacteremia. A contamination (only one positive blood culture of the three sampling times) with coagulase-negative staphylococci occurred in four patients at blood culture 1, five patients at blood culture 2, and six patients at blood culture 3. Contamination with Corynebacterium species occurred in two patients at blood culture 2. In one patient receiving cefotaxime and netilmicin, blood culture 1 was sterile and blood cultures 2 and 3 yielded coagulase-negative staphylococci. In one patient receiving no antibiotic treatment, blood culture 1 was sterile and blood cultures 2 and 3 yielded Enterococcus faecalis. None of these two patients received a specific antibiotic treatment or developed any secondary septic focus. CONCLUSIONS: The overall frequency of bacteremia induced by transesophageal echocardiography in ICU patients was 1.4% (two of 139 patients) (95% confidence interval 0.2% to 5.1%). The frequency did not differ whether patients received antibiotics before transesophageal echocardiography (one [1.2%] of 83 patients) or not (one [1.8%] of 56 patients) (p = .96). Therefore, routine antimicrobial prophylaxis does not appear justified before transesophageal echocardiography in ICU patients.

Adult↗
PubMed1995

Titration of tidal volume and induced hypercapnia in acute respiratory distress syndrome.

Mechanical ventilation may promote overdistension-induced pulmonary lesions in patients with acute respiratory distress syndrome (ARDS). The static pressure-volume (P-V) curve of the respiratory system can be used to determine the lung volume and corresponding static airway pressure at which lung compliance begins to diminish (the upper inflection point, or UIP). This fall in compliance may indicate overdistension of lung units. We prospectively studied 42 patients receiving mechanical ventilation with an FIO2 of 0.5 or more for at least 24 h. According to the Lung Injury Score (LIS), 25 patients were classified as having ARDS (LIS > 2.5), while 17 patients constituted a non-ARDS control group. The P-V curve was obtained every 2 d. Mechanical ventilation initially used standard settings (volume-control mode, a positive end-expiratory pressure [PEEP] adjusted to the lower inflection point on the P-V curve, and a tidal volume [VT] of 10 ml/kg). The end-inspiratory plateau pressure (Pplat) was compared to the UIP, and VT was lowered when the Pplat was above the UIP. In the range of lung volume studied on the P-V curves (up to 1600 ml), a UIP could be shown in only one control patient (at 23 cm H2O). By contrast, a UIP was present on the P-V curve obtained from all patients with ARDS, corresponding to a mean airway pressure of 26 +/- 6 cm H2O, a lung volume of 850 +/- 200 ml above functional residual capacity and 610 +/- 235 ml above PEEP.(ABSTRACT TRUNCATED AT 250 WORDS)

Case-Control Studies↗
PubMed1995

Comparative effects of pressure support ventilation and intermittent positive pressure breathing (IPPB) in non-intubated healthy subjects.

We compared the efficacy of three devices delivering assisted non-invasive ventilation with different working mechanisms, during room air breathing and during CO2-induced hyperventilation. In seven healthy volunteers, breathing pattern, respiratory muscle activity and comfort were assessed: during unassisted spontaneous breathing through a mouth-piece (SB); during assisted breathing with a device delivering inspiratory pressure support (IPS); and with two devices delivering intermittent positive pressure breathing (IPPB), the Monaghan 505 (IPPB1), and the CPU 1 ventilator (IPPB2). All three devices were set at 10 cmH2O of maximal pressure. During room air breathing, the work of breathing expressed as power, was significantly greater with the two IPPB devices than with the two other modes (IPPB1 and IPPB2 7.3 +/- 5.2 and 7.2 +/- 6.2 J.min-1, respectively, versus SB and IPS 2.4 +/- 0.7 and 2.3 +/- 3.3 J.min-1, respectively). The difference did not reach the statistical significance for the pressure-time product (PTP). Discomfort was also greater during the IPPB modes. During CO2-induced hyperventilation, considerable differences in power of breathing were found between the two IPPB devices and the other two modes. The PTP was also much higher with IPPB. Transdiaphragmatic pressure was significantly smaller during IPS than during the three other modes (IPS 18 +/- 2.6 cmH2O versus SB 22 +/- 2.6, IPPB1 32 +/- 5.2, and IPPB2: 28 +/- 5.2). Maximal discomfort was observed during the IPPB modes and was correlated with the magnitude of transdiaphragmatic pressure (r = 0.60). Despite similarities in their operational principles, IPS and IPPB had very different effects on respiratory muscle activity in healthy non-intubated subjects. IPPB machines not only failed to reduce patient's effort but also induced a significant level of extra work by comparison to spontaneous ventilation at ambient pressure. Great caution is, therefore, needed in the use of patient-triggered devices for non-intubated patients with acute respiratory failure.

Adult↗
PubMed1995

[Non-invasive ventilation in acute respiratory insufficiency in chronic obstructive bronchopneumopathy].

At the time of acute exacerbations of chronic airflow obstruction (BPCO) non-invasive ventilation represents an alternative to endotracheal intubation. In patients with respiratory distress, the use of a face mask is often preferable to a nasal mask alone, by avoiding the escape of oxygen which occurs around the mouth in nasal ventilation. The inspiratory aid is a type of ventilation which permits good synchronisation with the spontaneous activity of the patient; it leads to a reduction of respiratory effort developed by the patient and at the same time improves oxygenation and alveolar ventilation. In a recent randomised multicentre trial in 85 BPCO patients with severe respiratory distress, the level of intubation was reduced from 74 to 26 per cent by ventilation with an inspiratory mask. The consequences were a significant reduction of the complications of acute respiratory failure which were linked to artificial ventilation (p < 0.05) with a reduction of the hospital stay (p < 0.05) and finally a significant reduction in mortality (29 per cent - 9 per cent, p < 0.005). From now on, this technique could be used in many centres as the first treatment in acute exacerbations of BPCO patients to avoid the use of endotracheal intubation.

Acute Disease↗
PubMed1994

Additive effect on gas exchange of inhaled nitric oxide and intravenous almitrine bismesylate in the adult respiratory distress syndrome.

OBJECTIVE: To assess the additive effect of inhaled nitric oxide (NO) and intravenous almitrine bismesylate (ALM) on gas exchange. DESIGN: Prospective self-controlled study. SETTING: 3 medico-surgical intensive care units. PATIENTS: 17 patients with severe hypoxemia (PaO2/FIO2 ratio: 88 +/- 30 mmHg, venous admixture: 47 +/- 7%) and elevated mean pulmonary artery pressure (MPAP: 30 +/- 5 mmHg) due to adult respiratory distress syndrome (ARDS). INTERVENTIONS: 5 conditions were studied: 1) baseline, 2) 5 to 10 ppm of NO during 30 min, 3) discontinuation of NO during 30 min, 4) ALM infusion (0.5 mg/kg) during 30 min, 5) ALM infusion (0.5 mg/kg) during 30 min in combination with 5 to 10 ppm of NO. MEASUREMENT AND RESULTS: The PaO2/FIO2 ratio rose from 88 +/- 30 to 98 +/- 37 mmHg (NS) with NO alone, and from 92 +/- 25 to 130 +/- 56 mmHg (p < 0.01) with NO + ALM (p < 0.05 vs NO alone). Seven patients were considered as "NO-responders" (rise in PaO2/FIO2 ratio of 10 mmHg or more with NO); in this subgroup the PaO2/FIO2 ratio rose from 87 +/- 30 to 128 +/- 39 mmHg (p < 0.05) with NO alone, and from 93 +/- 20 to 169 +/- 51 mmHg (p < 0.01) with NO + ALM (p < 0.05 versus NO alone). MPAP decreased from 30 +/- 5 to 26 +/- 5 mmHg (p < 0.01) with NO alone, increased slightly from 28 +/- 5 to 31 +/- 5 mmHg (NS) with ALM alone and decreased to 27 +/- 5 mmHg (p < 0.05) with NO + ALM. CONCLUSIONS: NO + ALM had additive effects on gas exchange while decreasing MPAP in patients with ARDS. The effects of NO alone were small and non significant, except in a subgroup of 7 patients in whom the combination of both therapies had the more pronounced results.

Administration, Inhalation↗
PubMed1994

Pulmonary artery catheterization in critically ill patients: a prospective analysis of outcome changes associated with catheter-prompted changes in therapy.

OBJECTIVE: To evaluate physician accuracy in predicting patients' hemodynamic profiles, associated morbidities, rates of change in therapy resulting from catheterization, and the outcome variations associated with such change before the insertion of a pulmonary artery catheter. DESIGN: Prospective, descriptive, cohort study with no interventions. SETTING: Medical intensive care unit (ICU) of a university hospital. PATIENTS: One hundred twelve catheterizations performed in 112 patients without acute myocardial infarction. In 43 cases, catheterizations were indicated because of circulatory shock that was unresponsive to two standard therapeutic measures. MEASUREMENTS AND MAIN RESULTS: Before catheterization, physicians were asked to predict the hemodynamic profile of the patients who were to be catheterized, and to provide a plan for therapy. After catheterization, each patient's chart was reviewed and compared with precatheterization predictions. Hemodynamic profiles were correctly predicted in only 56% of the cases. Information obtained from pulmonary artery catheters prompted changes in therapy in 58% of all cases and in 63% of patients in shock who were unresponsive to standard therapy. Modifications varied among hemodynamic profiles, from 33% (fluid overloaded) to 87% (hypovolemia). Complications occurred in 11 catheterizations, but only two complications required therapy (pneumothorax [n = 1] and one episode of arrhythmia). No systemic infection occurred, and all blood cultures sampled through catheters before the catheters were withdrawn were sterile. In the entire group of patients, those patients in whom catheterization induced a change in therapy and those patients in whom no change in therapy occurred had similar precatheterization characteristics and mortality rates. However, in the subgroup of patients in shock that was unresponsive to standard therapy, the mortality rate was significantly lower when the assessment of hemodynamic data led to a change in therapy (59% vs. 100%, p = .009), despite identical precatheterization characteristics. CONCLUSIONS: Prompted by assessment of pulmonary artery catheter measurements in patients with circulatory shock who were unresponsive to standard therapeutic measures, a change in therapy for these patients was associated with an improved prognosis, independent of other variables influencing outcome.

Adult↗
PubMed1994

Comparison of three methods of gradual withdrawal from ventilatory support during weaning from mechanical ventilation.

Several modalities of ventilatory support have been proposed to gradually withdraw patients from mechanical ventilation, but their respective effects on the outcome of weaning from mechanical ventilation are not known. We conducted a randomized trial in three intensive care units in mechanically ventilated patients who met standard weaning criteria. Those who could not sustain 2 h of spontaneous breathing were randomly assigned to be weaned with T-piece trials, with synchronized intermittent mandatory ventilation (SIMV), or with pressure support ventilation (PSV). Specific criteria for performing tracheal extubation were defined for each modality. The number of patients who could not be separated from the ventilator at 21 d (i.e., who failed to wean) was compared between the groups. Patients in whom tracheal intubation was required in a 48-h period following extubation were also classified as failures. Among 456 mechanically ventilated patients who met weaning criteria, 109 entered into the study (35 with T piece, 43 with SIMV, and 31 with PSV). The three groups were comparable in terms of etiology of disease or characteristics at entry in the study. When all causes for weaning failure were considered, a lower number of failures was found with PSV than with the other two modes, with the difference just reaching the level of significance (23% for PSV, 43% for T piece, 42% for SIMV; p = 0.05). After excluding patients whose weaning was terminated for complications unrelated to the weaning process, the difference became highly significant (8% for PSV versus 33% and 39%, p < 0.025).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Diagnostic accuracy and therapeutic impact of transthoracic and transesophageal echocardiography in mechanically ventilated patients in the ICU.

STUDY OBJECTIVES: To assess the respective diagnostic accuracy of transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) and their therapeutic implications in mechanically ventilated patients, in the intensive care unit (ICU). DESIGN: A prospective study. SETTINGS: Intensive care units of two tertiary referral teaching hospitals. PATIENTS: One hundred eleven ICU patients (81 men and 30 women; mean age 57 +/- 16 years). Fifty-seven percent were hospitalized for medical illnesses, 16.5 percent after thoracic surgery, 10.5 percent after other surgery, and 16.0 percent for multiple trauma. Their Simplified Acute Physiologic Score was 16 +/- 5. INTERVENTIONS: The echocardiograms were performed in order to solve well-defined clinical problems. TTE was the first step of the procedure and TEE was performed only when (1) TTE did not solve the clinical problems, and (2) TTE yielded unsuspected findings requiring TEE. During each echocardiographic study, the following were noted: ventilatory mode, clinical problems, imaging quality, results, consequence on acute care, duration of the procedure, and potential complications of TEE. Diagnostic accuracy was defined as the proportion of solved problems, and therapeutic impact was defined as changes on acute care that resulted directly from the procedure. MEASUREMENTS AND RESULTS: One hundred twenty-eight consecutive TTE and 96 TEE were performed. TTE solved 60 of 158 clinical problems (38 percent), whether positive end-expiratory pressure (> 4 cm H2O) was present or not (28 of 74 vs 32 of 84: p > 0.50). TTE allowed evaluation of left ventricular function in 77 percent of cases and pericardial effusion in every case, but it did not solve most of the other clinical problems. Indeed, the diagnostic accuracy of TEE was markedly superior (95/98 vs 60/158: p < 0.001), but TEE required a physician's presence longer (43 +/- 17 min vs 27 +/- 12 min: p < 0.001). When TTE and TEE were scheduled (n = 96), TEE yielded an additional diagnosis or excluded with more certitude a suspected diagnosis, except in two cases. TEE had a therapeutic impact more frequently than TTE (35/96 vs 20/128: p < 0.001). Cardiovascular surgery was prompted by echocardiographic findings in ten patients. TEE was well tolerated in all patients; there were no complications. CONCLUSIONS: TEE is a valuable well-tolerated imaging technique in mechanically ventilated patients. For the assessment of left ventricular systolic function and pericardial effusion; however, TTE continues to be an excellent diagnostic tool, even when positive end-expiratory pressure is present. Both TTE and TEE have a therapeutic impact in approximately 25 percent of cases.

Echocardiography↗
PubMed1994

Effects of pressure-controlled with different I:E ratios versus volume-controlled ventilation on respiratory mechanics, gas exchange, and hemodynamics in patients with adult respiratory distress syndrome.

BACKGROUND: Pressure-controlled (PCV) and pressure-controlled inverse ratio ventilation (PCIRV) have been proposed instead of volume-controlled conventional ratio ventilation (VC) with positive end-expiratory pressure (PEEP) for patients with adult respiratory distress syndrome (ARDS). The advantages advocated with the use of PCIRV are to decrease airway pressures and to improve gas exchange. However, most studies did not compare PCIRV and VC while keeping both the level of ventilation and end-expiratory alveolar pressure (total-PEEP) constant. METHODS: Nine patients with moderate to severe ARDS (lung injury score 2.83 +/- 0.18) had their lungs ventilated with VC, PCV with a conventional ratio (I:E 1:2; PC 1/2), and PCIRV (I:E 2:1 and 3:1; PC 2/1 and PC 3/1, respectively). Ventilator settings were adjusted to keep tidal volume, respiratory rate, FIo2, and total-PEEP constant in every mode. With each mode, a complete set of ventilatory, hemodynamic, and gas exchange parameters was obtained after 30 min. RESULTS: In PC 3/1, the data obtained could not be strictly compared to the other modes because total-PEEP was higher despite external-PEEP being set at zero. For the other modes (VC, PC 1/2, and PC 2/1), despite differences in peak airway pressures, no difference was noted for end-inspiratory and end-expiratory static airway pressures (which better reflect alveolar pressures) nor for lung and respiratory system compliance. Arterial oxygenation deteriorated slightly with PC 2/1 despite a higher mean airway pressure, whereas alveolar ventilation tended to be slightly, but not significantly, improved (lower PaCo2). A decrease in systolic and mean arterial pressure also was observed with PC 2/1 without other significant hemodynamic change. CONCLUSIONS: In this prospective controlled study, no short-term beneficial effect of PCV or PCIRV could be demonstrated over conventional VC with PEEP in patients with ARDS.

Adult↗
PubMed1994

Clinically relevant diaphragmatic dysfunction after cardiac operations.

Phrenic nerve injury and diaphragmatic dysfunction can be induced by cardiac operation. The clinical consequences are not well-established. We evaluated 13 consecutive patients over a 2-year period with unexplained and prolonged difficulties in weaning from mechanical ventilation. The mean time of measurement from the operation day was 31 +/- 19 days (range 8 to 78). With the same technique we also evaluated 12 control patients: four patients at day 1 after cardiac operation while they were still intubated; four normally convalescing patients at day 7 or 8 after cardiac operation; and four patients who required prolonged mechanical ventilation because of another identified cause after cardiac operation. Diaphragmatic function was evaluated at the bedside from esophageal and gastric pressure measurements. A low or negative ratio of gastric pressure swing to transdiaphragmatic pressure swing, indicative of diaphragm dysfunction, was found in all 13 patients (mean -0.39 +/- 0.64). The difference between the 13 patients and all control groups was found to be highly significant. Transdiaphragmatic pressure measured during a maximal voluntary inspiratory effort and transdiaphragmatic pressure measured during a short, sharp sniff were markedly diminished (28 +/- 18 cm H2O and 13 +/- 15 cm H2O, respectively) in the 13 patients, significantly different from values in the four control patients studied at day 7 or 8. Transdiaphragmatic pressure measured after magnetic stimulation in four patients was also markedly reduced (7 +/- 5 cm H2O) as compared with normal theoretic values. Aminophylline infusion had no effect on any of these parameters. In one of two patients evaluated a second time, about 5 weeks later, a marked improvement was observed. Estimating the prevalence of clinically relevant diaphragmatic dysfunction, we found it to be 0.5% when no topical cooling was used and 2.1% when iced slush with no insulation pad was added for myocardial protection (p < 0.005). The most striking finding was that the clinical course of the 13 patients was marked by severe intercurrent events, including cardiorespiratory arrest after early tracheal extubation in 5 patients, nosocomial pneumonia in 11, prolonged mechanical ventilation in all (58 +/- 41 days), and a fatal outcome in 3. We conclude that prolonged postoperative diaphragmatic dysfunction may cause severe life-threatening complications after cardiac operation and can be limited to some extent by avoiding the use of iced slush topical cooling of the heart.

Adult↗
PubMed1993

Dependence of shunt on cardiac output in unilobar oleic acid edema. Distribution of ventilation and perfusion.

OBJECTIVE: In acute respiratory failure, increased cardiac output (Qt) increases shunt (Qs/Qt). We have tested if this is caused by: 1) a redistribution of blood flow towards edematous regions, or 2) a decrease of regional ventilation in the edematous region. DESIGN: Oleic acid edema was induced in the left lower lobe (LLL) of 11 pigs. Qt was varied with bleeding and infusion of blood and dextran. Blood flow to the LLL was measured at low and high Qt with electromagnetic low probes in 6 animals and with a gamma camera in 5. In the gamma camera pigs regional ventilation was also measured. MEASUREMENTS AND RESULTS: Qt was increased by 45% (electromagnetic flow probes) and 73% (gamma camera). Qs/Qt increased from 24.9-31.3% (p < 0.05) and from 17.6-28.8% (p < 0.001) respectively. No change in fractional perfusion of LLL could be seen, neither with flow probes nor with gamma camera. A decrease in ventilation of LLL, 2.6%, was observed when Qt was increased (p < 0.05). CONCLUSION: Theoretically a small decrease in ventilation can explain the increase in shunt, if regions with low ventilation/perfusion (VA/Q) ratio are transformed to shunt. This is, however, unlikely since earlier studies have shown that blood flow is distributed either to regions with normal VA/Q ratio or to shunt regions. We conclude that the cardiac output dependent shunt is not caused by redistribution of blood flow between lobes or by decreased ventilation in the edematous region. We cannot exclude that blood flow is redistributed within the edematous lobe.

Animals↗
PubMed1993

Hospital bad debt in France: who does not pay?

Hospital bad debt commonly represents 4-5% of total patient revenue. We examined bad debts accrued by our hospital over a 10-year period from both a medical and sociodemographic perspective. We found that true medical emergencies represent 90% of 'bad debtors' admitted, and that, despite generalized medical insurance in France, a quarter of unpaid bills belong to French residents. We conclude with a proposal to limit individual hospitals' accountability for bad debt.

Costs and Cost Analysis↗
PubMed1992

Usefulness of consensus conferences: the case of albumin.

The usefulness of consensus conferences has been questioned. We have assessed the impact of a 1989 consensus conference about the treatment of hypovolaemia on prescribing practice at our hospital. Data available from the blood bank enabled us to follow albumin use and costs by department between 1987 and 1991. Medical journals, direct mail, and meetings were used to disseminate the recommendations of the consensus conference, which were that the only indications for albumin are massive haemorrhage, plasmapheresis, massive hypoalbuminaemia, and volume expansion in pregnancy; for hypovolaemia caused by septic shock or vasoplegia, fluid gelatins and crystalloids should be used. In the year after the conference, and in subsequent years, albumin use and costs were 40% lower than before the conference, even though total medical expenditure continued to rise and numbers of patients admitted did not change. We believe that consensus conferences can be a useful means of improving medical practice. The features that ensured success in this programme were the small number of prescribers, the homogeneous setting, and the frequent restatement of the recommendations.

Consensus Statements as Topic↗