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Biomedical subjects

F Lemaire

Publications and source records attributed to F Lemaire.

At least 37 records · Page 2Linked to original sources
PubMed2001

Accuracy of pulse oximetry in the intensive care unit.

OBJECTIVE: Pulse oximetry (SpO2) is a standard monitoring device in intensive care units (ICUs), currently used to guide therapeutic interventions. Few studies have evaluated the accuracy of SpO2 in critically ill patients. Our objective was to compare pulse oximetry with arterial oxygen saturation (SaO2) in such patients, and to examine the effect of several factors on this relationship. DESIGN: Observational prospective study. SETTING: A 26-bed medical ICU in a university hospital. PATIENTS: One hundred two consecutive patients admitted to the ICU in whom one or serial arterial blood gas analyses (ABGs) were performed and a reliable pulse oximeter signal was present. INTERVENTIONS: For each ABG, we collected SaO2, SpO2, the type of pulse oximeter, the mode of ventilation and requirement for vasoactive drugs. MEASUREMENTS AND RESULTS: Three hundred twenty-three data points were collected. The mean difference between SpO2 and SaO2 was -0.02% and standard deviation of the differences was 2.1%. From one sample to another, the fluctuations in SpO2 to arterial saturation difference indicated that SaO2 could not be reliably predicted from SpO2 after a single ABG. Subgroup analysis showed that the accuracy of SpO2 appeared to be influenced by the type of oximeter, the presence of hypoxemia and the requirement for vasoactive drugs. Finally, high SpO2 thresholds were necessary to detect significant hypoxemia with good sensitivity. CONCLUSION: Large SpO2 to SaO2 differences may occur in critically ill patients with poor reproducibility of SpO2. A SpO2 above 94% appears necessary to ensure a SaO2 of 90%.

Bias↗
PubMed2001

French intensivists do not apply American recommendations regarding decisions to forgo life-sustaining therapy.

OBJECTIVE: Recommendations for making and implementing decisions to forgo life-sustaining therapy in intensive care units have been developed in the United States, but the extent that they are realized in practice has yet to be measured. DESIGN: Prospective, multicenter, 4-wk study. For each patient with an implemented decision to forgo life-sustaining therapy, the deliberation and decision implementation procedures were recorded. SETTING: French intensive care units. PATIENTS: All consecutive patients admitted to 26 French intensive care units. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Of 1,009 patients admitted, 208 died in the intensive care unit. A decision to forgo life-sustaining therapy was implemented in 105 patients. The number of supportive treatments forgone was 2.3 +/- 1.7 per patient. Decisions to forgo sustaining therapy were preceded by 3.5 +/- 2.5 deliberation sessions. Proxies were informed of the deliberations in 62 (59.1%) cases but participated in only 18 (17.1%) decisions. The patient's perception of his or her quality of life was rarely evaluated (11.5%), and only rarely did the decision involve evaluating the patient's wishes (7.6%), the patient's religious values (7.6%), or the cost of treatment (7.6%). Factors most frequently evaluated were medical team advice (95.3%), predicted reversibility of acute disease (90.5%), underlying disease severity (83.9%), and the patient's quality of life as evaluated by caregivers (80.1%). CONCLUSIONS: A decision to withhold or withdraw life-sustaining therapy was implemented for half the patients who died in the French intensive care units studied. In many cases, the decision was taken without regard for one or more factors identified as relevant in U.S. guidelines.

Adult↗
PubMed2001

Symptoms of anxiety and depression in family members of intensive care unit patients: ethical hypothesis regarding decision-making capacity.

OBJECTIVE: Anxiety and depression may have a major impact on a person's ability to make decisions. Characterization of symptoms that reflect anxiety and depression in family members visiting intensive care patients should be of major relevance to the ethics of involving family members in decision-making, particularly about end-of-life issues. DESIGN: Prospective multicenter study. SETTING: Forty-three French intensive care units (37 adult and six pediatric); each unit included 15 patients admitted for longer than 2 days. PATIENTS: Six hundred thirty-seven patients and 920 family members. INTERVENTIONS: Intensive care unit characteristics and data on the patient and family members were collected. Family members completed the Hospital Anxiety and Depression Scale to allow evaluation of the prevalence and potential factors associated with symptoms of anxiety and depression. MEASUREMENTS AND MAIN RESULTS: Of 920 Hospital Anxiety and Depression Scale questionnaires that were completed by family members, all items were completed in 836 questionnaires, which formed the basis for this study. The prevalence of symptoms of anxiety and depression in family members was 69.1% and 35.4%, respectively. Symptoms of anxiety or depression were present in 72.7% of family members and 84% of spouses. Factors associated with symptoms of anxiety in a multivariate model included patient-related factors (absence of chronic disease), family-related factors (spouse, female gender, desire for professional psychological help, help being received by general practitioner), and caregiver-related factors (absence of regular physician and nurse meetings, absence of a room used only for meetings with family members). The multivariate model also identified three groups of factors associated with symptoms of depression: patient-related (age), family-related (spouse, female gender, not of French descent), and caregiver-related (no waiting room, perceived contradictions in the information provided by caregivers). CONCLUSIONS: More than two-thirds of family members visiting patients in the intensive care unit suffer from symptoms of anxiety or depression. Involvement of anxious or depressed family members in end-of-life decisions should be carefully discussed.

Anxiety↗
PubMed2001

Liquid ventilation.

Partial liquid ventilation (PLV) developed considerably in the clinical and experimental fields during the past few years. In addition to improved oxygenation and lung mechanics by perfluorocarbon (PFC) administration, recent animal studies have tried to optimize PLV by evaluating the most appropriate ventilatory mode to use during PLV and by adjusting the best level of positive end-expiratory pressure (PEEP). Other pathophysiological aspects of acute lung injury that may be positively affected by liquid ventilation have been studied, including regional blood flow redistribution, reduction in ventilator-induced lung injury, and antiinflammatory properties of PFC. Although the precise dosing of PFC is debated, evidence from several experimental studies supports the use of smaller doses of PFC because larger doses increase the occurrence of baro- and volutrauma. In the clinical field, after promising data from preliminary studies, an international randomized controlled trial is on the verge of completion.

Fluorocarbons↗
PubMed2001

Meeting the needs of intensive care unit patient families: a multicenter study.

Intensive care unit (ICU) caregivers should seek to develop collaborative relationships with their patients' family members, based on an open exchange of information and aimed at helping family members cope with their distress and allowing them to speak for the patient if necessary. We conducted a prospective multicenter study of family member satisfaction evaluated using the Critical Care Family Needs Inventory. Forty-three French ICUs participated in the study. ICU characteristics, patient and family member demographics, and data on satisfaction were collected. Factors associated with satisfaction were identified using a Poisson regression model. A total of 637 patients were included in the study, and 920 family members completed the questionnaire. Seven predictors of family satisfaction were found: one family-related factor, namely, family of French descent and six caregiver-related factors, namely, no perceived contradictions in information given by caregivers; information provided by a junior physician; patient to nurse ratio </= 3; knowledge of the specific role of each caregiver; help from the family's own doctor; and sufficient time spent giving information. Predictors of satisfaction are amenable to intervention and deserve to be investigated further with the goal of improving the satisfaction of ICU patients' family members.

Adult↗
PubMed2001

Influence of tidal volume on alveolar recruitment. Respective role of PEEP and a recruitment maneuver.

Both reduction in tidal volume (VT) and alveolar recruitment may be important to limit ventilator-associated lung injury during mechanical ventilation of patients with the acute respiratory distress syndrome (ARDS). The aim of this study was to assess the risk of alveolar derecruitment associated with VT reduction from 10 to 6 ml/kg. Whether this VT-related derecruitment could be reversed, either by a recruitment maneuver or by an increase in positive end-expiratory pressure (PEEP) level, was also investigated. Fifteen patients with ARDS were successively ventilated using conventional VT (CVT = 10 +/- 1 ml/kg) and low VT (LVT = 6 +/- 1 ml/ kg); total PEEP (PEEPtot) was individually set at the lower inflection point (Plip) of the pressure-volume curve (PEEPtot = 11 +/- 4 cm H(2)O). Pressure-volume curves were recorded from zero PEEP (ZEEP) and from PEEP, and recruited volume (Vrec) was calculated as the volume difference between the two curves for a given pressure. Despite a similar PEEPtot, Vrec was significantly lower with LVT than with CVT, indicating low VT-induced alveolar derecruitment. Reduction in VT was associated with a reduced Sa(O(2)). In 10 patients, Vrec was also measured before and after a recruitment maneuver (two sustained inflations at 45 cm H(2)O), and after an increase in PEEP (by 4 cm H(2)O). Low VT-induced derecruitment was reversed by a recruitment maneuver and by increasing PEEP. We conclude that a reduction in VT could be responsible for alveolar derecruitment, which may be transiently reversed by a reexpansion maneuver or prevented by a PEEP increase above Plip.

Adult↗
PubMed2001

Spontaneous hemomediastinum complicating steroid-induced mediastinal lipomatosis.

Spontaneous hemomediastinum is a rare event, occurring in association with bleeding disorders, intratumoral bleeding, or following an abrupt increase in intrathoracic pressure. We report the case of a patient with systemic lupus erythematosus, nephrotic syndrome, and renal failure, in whom mediastinal lipomatosis (ML) developed following increased corticosteroid therapy. Anticoagulant therapy likely precipitated a massive spontaneous hemomediastinum secondary to diffuse hemorrhage of mediastinal fat, which required emergency decompressive surgery. Steroid-induced ML is common and usually well tolerated, but clinicians should be aware of its potential risk of bleeding when associated with anticoagulant therapy. This case further emphasizes the bleeding complications of treatment with low-molecular-weight heparin in patients with renal failure.

Adult↗
PubMed2000

Treatment of acute hypoxemic nonhypercapnic respiratory insufficiency with continuous positive airway pressure delivered by a face mask: A randomized controlled trial.

CONTEXT: Continuous positive airway pressure (CPAP) is widely used in the belief that it may reduce the need for intubation and mechanical ventilation in patients with acute hypoxemic respiratory insufficiency. OBJECTIVE: To compare the physiologic effects and the clinical efficacy of CPAP vs standard oxygen therapy in patients with acute hypoxemic, nonhypercapnic respiratory insufficiency. DESIGN, SETTING, AND PATIENTS: Randomized, concealed, and unblinded trial of 123 consecutive adult patients who were admitted to 6 intensive care units between September 1997 and January 1999 with a PaO(2)/FIO(2) ratio of 300 mm Hg or less due to bilateral pulmonary edema (n = 102 with acute lung injury and n = 21 with cardiac disease). INTERVENTIONS: Patients were randomly assigned to receive oxygen therapy alone (n = 61) or oxygen therapy plus CPAP (n = 62). MAIN OUTCOME MEASURES: Improvement in PaO(2)/FIO(2) ratio, rate of endotracheal intubation at any time during the study, adverse events, length of hospital stay, mortality, and duration of ventilatory assistance, compared between the CPAP and standard treatment groups. RESULTS: Among the CPAP vs standard therapy groups, respectively, causes of respiratory failure (pneumonia, 54% and 55%), presence of cardiac disease (33% and 35%), severity at admission, and hypoxemia (median [5th-95th percentile] PaO(2)/FIO(2) ratio, 140 [59-288] mm Hg vs 148 [62-283] mm Hg; P =.43) were similarly distributed. After 1 hour of treatment, subjective responses to treatment (P<.001) and median (5th-95th percentile) PaO(2)/FIO(2) ratios were greater with CPAP (203 [45-431] mm Hg vs 151 [73-482] mm Hg; P =.02). No further difference in respiratory indices was observed between the groups. Treatment with CPAP failed to reduce the endotracheal intubation rate (21 [34%] vs 24 [39%] in the standard therapy group; P =.53), hospital mortality (19 [31%] vs 18 [30%]; P =.89), or median (5th-95th percentile) intensive care unit length of stay (6.5 [1-57] days vs 6.0 [1-36] days; P =.43). A higher number of adverse events occurred with CPAP treatment (18 vs 6; P =.01). CONCLUSION: In this study, despite early physiologic improvement, CPAP neither reduced the need for intubation nor improved outcomes in patients with acute hypoxemic, nonhypercapnic respiratory insufficiency primarily due to acute lung injury. JAMA. 2000;284:2352-2360.

APACHE↗
PubMed2000

Association of noninvasive ventilation with nosocomial infections and survival in critically ill patients.

CONTEXT: Invasive life-support techniques are a major risk factor for nosocomial infection. Noninvasive ventilation (NIV) can be used to avoid endotracheal intubation and may reduce morbidity among patients in intensive care units (ICUs). OBJECTIVE: To determine whether the use of NIV is associated with decreased risk of nosocomial infections and improved survival in everyday clinical practice among patients with acute exacerbation of chronic obstructive pulmonary disease (COPD) or hypercapnic cardiogenic pulmonary edema (CPE). DESIGN AND SETTING: Matched case-control study conducted in the medical ICU of a French university hospital from January 1996 through March 1998. PATIENTS: Fifty patients with acute exacerbation of COPD or severe CPE who were treated with NIV for at least 2 hours and 50 patients treated with mechanical ventilation between 1993 and 1998 (controls), matched on diagnosis, Simplified Acute Physiology Score II, Logistic Organ Dysfunction score, age, and no contraindication to NIV. MAIN OUTCOME MEASURES: Rates of nosocomial infections, antibiotic use, lengths of ventilatory support and of ICU stay, ICU mortality, compared between cases and controls. RESULTS: Rates of nosocomial infections and of nosocomial pneumonia were significantly lower in patients who received NIV than those treated with mechanical ventilation (18% vs 60% and 8% vs 22%; P<.001 and P =.04, respectively). Similarly, the daily risk of acquiring an infection (19 vs 39 episodes per 1000 patient-days; P =.05), proportion of patients receiving antibiotics for nosocomial infection (8% vs 26%; P =.01), mean (SD) duration of ventilation (6 [6] vs 10 [12] days; P =.01), mean (SD) length of ICU stay (9 [7] vs 15 [14] days; P =.02), and crude mortality (4% vs 26%; P =.002) were all lower among patients who received NIV than those treated with mechanical ventilation. CONCLUSIONS: Use of NIV instead of mechanical ventilation is associated with a lower risk of nosocomial infections, less antibiotic use, shorter length of ICU stay, and lower mortality. JAMA. 2000;284:2361-2367.

APACHE↗
PubMed2000

Patients' preferences concerning medical information and surrogacy: results of a prospective study in a French emergency department.

OBJECTIVE: To study the wishes of a sample of French patients about medical information and surrogacy, at a time when the French Ministry of Health is supporting increased patient autonomy. DESIGN: A cohort of competent patients with non-critical illnesses or injuries completed an intention-to-act questionnaire on the amount of medical information they would want to receive should they be hospitalized or in a life-threatening situation. The percentage of patients who would want to have a surrogate if they were in a coma was determined, as well as the identity of the preferred surrogate. The subgroup of patients who were married or living with a partner was evaluated separately to determine how often the spouse/partner was the preferred surrogate. Associations were looked for between patients' wishes and age, sex, educational level, occupation, hierarchical order in the family, and level of confidence in medicine. SETTING: The emergency room of a teaching hospital in the Paris area (France). RESULTS: Of the 1089 patients included in the study, 5. 5 % reported that they would not want any information, 25.3 % that they would want to participate actively in all decisions about their care, and 87.3 % that they would want to be fully informed if they were in a life-threatening situation. Slightly less than one-third of the patients (29.6 %) believed they would not want a surrogate if they developed a coma. Among the patients living with a spouse/partner, 40.6 % (229/561) indicated they would want their spouse/partner to be their surrogate. A significant correlation was observed between wanting more information and wanting a surrogate. Younger patients with a higher educational level were significantly more likely to predict a desire for information and for a surrogate than the other patients. CONCLUSION: Our patients expressed a strong desire to receive extensive information should they become seriously ill, and two-thirds of them reported they would want a surrogate. However, only 40.6 % of the patients living with a spouse/partner would want their spouse/partner to be their surrogate. These data suggest that the time has probably come to propose a nation-wide public hearing on medical information and surrogacy in France.

Adult↗
PubMed2000

Airway occlusion pressure to titrate positive end-expiratory pressure in patients with dynamic hyperinflation.

BACKGROUND: Although the use of external positive end-expiratory pressure (PEEP) is recommended for patients with intrinsic PEEP, no simple method exists for bedside titration. We hypothesized that the occlusion pressure, measured from airway pressure during the phase of ventilator triggering (P0.1t), could help to indicate the effects of PEEP on the work of breathing (WOB). METHODS: Twenty patients under assisted ventilation with chronic obstructive pulmonary disease were studied with 0, 5, and 10 cm H2O of PEEP while ventilated with a fixed level of pressure support. RESULTS: PEEP 5 significantly reduced intrinsic PEEP (mean +/- SD, 5.2 +/- 2.4 cm H2O at PEEP 0 to 3.6 +/- 1.9 at PEEP 5; P < 0.001), WOB per min (12. 6 +/- 6.7 J/min to 9.1 +/- 5.9 J/min; P = 0.003), WOB per liter (1.2 +/- 0.4 J/l to 0.8 +/- 0.4 J/l; P < 0.001), pressure time product of the diaphragm (216 +/- 86 cm H2O. s-1. min-1 to 155 +/- 179 cm H2O. s-1. min-1; P = 0.001) and P0.1t (3.3 +/- 1.5 cm H2O to 2.3 +/- 1.4 cm H2O; P = 0.002). At PEEP 10, no further significant reduction in muscle effort nor in P0.1t (2.5 +/- 2.1 cm H2O) occurred, and transpulmonary pressure indicated an increase in end-expiratory lung volume. Significant correlations were found between WOB per min and P0.1t at the three levels of PEEP (P < 0.001), and between the changes in P0.1t versus the changes in WOB per min (P < 0.005), indicating that P0.1t and WOB changed in the same direction. A decrease in P0.1 with PEEP indicated a decrease in intrinsic PEEP with a specificity of 71% and a sensitivity of 88% and a decrease in WOB with a specificity of 86% and a sensitivity of 91%. CONCLUSION: These results show that P0.1t may help to assess the effects of PEEP in patients with intrinsic PEEP.

Adult↗
PubMed2000

Are institutional review boards effective in safeguarding patients in intensive care units?

Institutional Review Boards have been recently audited in the US, and a great deal of concerns and criticisms appeared in the medical literature and the lay press. Globally, these comments questioned the efficiency of Institutional Review Boards in fulfilling their basic mission, the protection of patients subjected to biomedical research. Vulnerable populations, such as psychiatric and incompetent patients, were particularly identified. In intensive care units, conducting research in critically ill patients unable to give informed consent themselves remains a hot issue. Several possibilities have been proposed and assessed in the recent past: pre-emptive (global) consent, proxy consent from a surrogate, deferred consent, and, more recently, waiver of consent for emergency research. Obviously, the inability to deal with this major obstacle (i.e. obtaining consent from incompetent patients) would lead to the cessation of any research in intensive care units, which is hardly acceptable and certainly unethical. Recent published studies have reported over-mortality in treatment groups, posing new questions: who should be informed of those failures, and when? What is the role of Institutional Review Boards in preventing such an issue? What type of indemnity should be proposed to the family of deceased patients during a trial?

Journal Article↗
PubMed2000

Clinical evaluation of a computer-controlled pressure support mode.

We have designed a computerized system providing closed-loop control of the level of pressure support ventilation (PSV). The system sets itself at the lowest level of PSV that maintains respiratory rate (RR), tidal volume (VT), and end-tidal CO(2) pressure (PET(CO(2))) within predetermined ranges defining acceptable ventilation (i.e., 12 < RR < 28 cycles/min, VT > 300 ml [> 250 if weight < 55 kg], and PET(CO(2)) < 55 mm Hg [< 65 mm Hg if chronic CO(2) retention]). Ten patients received computer-controlled (automatic) PSV and physician-controlled (standard) PSV, in random order, during 24 h for each mode. An estimation of occlusion pressure (P(0.1)) was recorded continuously. The average time spent with acceptable ventilation as previously defined was 66 +/- 24% of the total ventilation time with standard PSV versus 93 +/- 8% with automatic PSV (p < 0.05), whereas the level of PSV was similar during the two periods (17 +/- 4 cm H(2)O versus 19 +/- 6 cm H(2)O). The time spent with an estimated P(0.1) above 4 cm H(2)O was 34 +/- 35% of the standard PSV time versus only 11 +/- 17% of the automatic PSV time (p < 0.01). Automatic PSV increased the time spent within desired ventilation parameter ranges and apparently reduced periods of excessive workload.

Aged↗