Christophe Girault

High-Flow Oxygen through Nasal Cannula in Acute Hypoxemic Respiratory Failure

BACKGROUND Whether noninvasive ventilation should be administered in patients with acute hypoxemic respiratory failure is debated. Therapy with high-flow oxygen through a nasal cannula may offer an alternative in patients with hypoxemia. METHODS We performed a multicenter, open-label trial in which we randomly assigned patients without hypercapnia who had acute hypoxemic respiratory failure and a ratio of the partial pressure of arterial oxygen to the fraction of inspired oxygen of 300 mm Hg or less to high-flow oxygen therapy, standard oxygen therapy delivered through a face mask, or noninvasive positive-pressure ventilation. The primary outcome was the proportion of patients intubated at day 28; secondary outcomes included all-cause mortality in the intensive care unit and at 90 days and the number of ventilator-free days at day 28. RESULTS A total of 310 patients were included in the analyses. The intubation rate (primary outcome) was 38% (40 of 106 patients) in the high-flow-oxygen group, 47% (44 of 94) in the standard group, and 50% (55 of 110) in the noninvasive-ventilation group (P=0.18 for all comparisons). The number of ventilator-free days at day 28 was significantly higher in the high-flow-oxygen group (24±8 days, vs. 22±10 in the standard-oxygen group and 19±12 in the noninvasive-ventilation group; P=0.02 for all comparisons). The hazard ratio for death at 90 days was 2.01 (95% confidence interval [CI], 1.01 to 3.99) with standard oxygen versus high-flow oxygen (P=0.046) and 2.50 (95% CI, 1.31 to 4.78) with noninvasive ventilation versus high-flow oxygen (P=0.006). CONCLUSIONS In patients with nonhypercapnic acute hypoxemic respiratory failure, treatment with high-flow oxygen, standard oxygen, or noninvasive ventilation did not result in significantly different intubation rates. There was a significant difference in favor of high-flow oxygen in 90-day mortality. (Funded by the Programme Hospitalier de Recherche Clinique Interrégional 2010 of the French Ministry of Health; FLORALI ClinicalTrials.gov number, NCT01320384.).

Unplanned extubation: risk factors of development and predictive criteria for reintubation.

OBJECTIVES To define patients at risk for unplanned extubation; to assess the influence of nursing workload on the incidence of unplanned extubation; and to determine predictive criteria for patients requiring reintubation. DESIGN A prospective, case-control study, with 10 and 15 mos of data collection. SETTING University medical intensive care department. PATIENTS In the first study, which lasted 10 mos, unplanned extubation occurred in 40 (14%) of 281 ventilated and intubated patients; 36 cases were sufficiently documented to be compared with 74 intubated and ventilated controls. In the second study, which lasted 15 mos, the reintubated patients (n=23) of a series of 62 unplanned extubation patients were compared with those who were not reintubated (n=39). INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS The following parameters were recorded: gender, age, main reason for admission, Simplified Acute Physiology Score II, route of intubation (oral or nasotracheal), tube diameter, ventilatory mode, FiO2, frequency and tidal volume delivered by the ventilator immediately before unplanned extubation, arterial blood gases performed 24 hrs before unplanned extubation, the presence of any sedation with, in this case, the last Ramsay score, the presence of hand restraints, the presence of weaning of ventilation, the accidental or deliberate nature of unplanned extubation, the Glasgow Coma Score at the time of unplanned extubation, the duration of ventilation before unplanned extubation, total duration of ventilation and stay in the intensive care unit, and the patients survival or death. The nursing workload was evaluated using a score derived from the Projet de Recherche en Nursing and adapted to intensive care. Unplanned extubation patients were more frequently intubated orally than controls (33.3% vs. 14.9%, respectively; p< .05). In the population of sedated patients, unplanned extubation patients were more frequently agitated than controls (60% vs. 19%, respectively; p < .05). The nursing workload did not differ between days with and days without unplanned extubation. Twenty-three (37%) of the 62 cases of documented unplanned extubation were reintubated. Predictive factors of reintubation are, in decreasing order of importance: Glasgow Coma Score of <11, accidental nature of unplanned extubation, and a PaO2/FiO2 ratio <200 torr (<26.7 kPa). CONCLUSIONS Patients at risk for unplanned extubation are characterized by oral intubation and insufficient sedation. In the department studied, and with the specific score used, we did not observe a relationship between the nursing workload and the incidence of unplanned extubation. A Glasgow Coma Score of <11, the accidental nature of unplanned extubation, and a PaO2/FiO2 ratio <200 torr (<26.7 kPa) are factors associated with a risk of reintubation.

Detrimental role of delayed antibiotic administration and penicillin-nonsusceptible strains in adult intensive care unit patients with pneumococcal meningitis: The PNEUMOREA prospective multicenter study*

Objective:To identify factors associated with mortality and morbidity among adults admitted to intensive care units (ICUs) for pneumococcal meningitis, particularly the impact of delayed antibiotic administration. Design:We conducted a prospective, multicenter, observational study of 156 consecutive adults hospitalized for pneumococcal meningitis. We analyzed parameters associated with 3-month survival. Setting:Fifty-six medical and medical-surgical ICUs in France. Intervention:None. Results:Of the 148 strains isolated, 56 (38%) were nonsusceptible to penicillin G. At 3 months after ICU admission, the mortality rate was 33% (51/156), and 34% of survivors (36/105) had neurologic sequelae. Multivariate analysis identified three variables as independently associated with 3-month mortality: Simplified Acute Physiology Score II (odds ration [OR], 1.12; 95% confidence interval [CI], 1.072–1.153; p = .002); isolation of a nonsusceptible strain (OR, 6.83; 95% CI, 2.94–20.8; p < 10−4), and an interval of >3 hrs between hospital admission and administration of antibiotics (OR, 14.12; 95% CI, 3.93–50.9; p < 10−4). In contrast, a cerebrospinal fluid leukocyte count >103 cells/&mgr;L had a protective effect (OR, 0.30; 95% CI, 0.10–0.944; p = 0.04). Conclusions:Independent of severity at the time of ICU admission, isolation of penicillin-nonsusceptible strains and a delay in antibiotic treatment following admission were predictors of mortality among patients with pneumococcal meningitis.

Increased initial flow rate reduces inspiratory work of breathing during pressure support ventilation in patients with exacerbation of chronic obstructive pulmonary disease

ObjectiveTo investigate whether the level of initial flow rate alters the work of breathing in chronic obstructive pulmonary disease (COPD) patients ventilated in pressure support ventilation (PSV).DesignProspective study.SettingsMedical ICU in University hospital.PatientsEleven intubated COPD patients.MethodsWe modulated the initial flow rate in order to achieve seven different sequences. In each sequence, the plateau pressure was reached within a predetermined time: 0.1, 0.25, 0.50, 0.75, 1, 1.25 or 1.50 s. The more rapidly the pressure plateau was achieved, the higher was the initial flow rate. In each patient, the pressure support level was an invariable parameter. The order of the seven sequences for each patient was determined randomly.Measurements and resultsTen minutes after application of each initial flow rate, we measured the following parameters: inspiratory work of breathing, electromyogram (EMG) of the diaphragm (EMGdi), breathing pattern, and intrinsic positive end-expiratory pressure (PEEPi). Comparison between the means for each sequence and each variable measured was performed by two-way analysis of variance with internal comparisons between sequences by Duncans test. The reduction of the initial flow rate induced a progressive increase in the values of the work of breathing, EMGdi, and mouth occlusion pressure (P 0.1). In contrast, the reduction of the initial flow rate did not induce any significant change in tidal volume, respiratory frequency or PEEPi.ConclusionAs the objective of PSV is to reduce the work of breathing, it seems logical to use the highest initial flow rate to induce the lowest possible work of breathing in COPD ventilated patients.

Effect of Noninvasive Ventilation vs Oxygen Therapy on Mortality Among Immunocompromised Patients With Acute Respiratory Failure: A Randomized Clinical Trial

IMPORTANCE Noninvasive ventilation has been recommended to decrease mortality among immunocompromised patients with hypoxemic acute respiratory failure. However, its effectiveness for this indication remains unclear. OBJECTIVE To determine whether early noninvasive ventilation improved survival in immunocompromised patients with nonhypercapnic acute hypoxemic respiratory failure. DESIGN, SETTING, AND PARTICIPANTS Multicenter randomized trial conducted among 374 critically ill immunocompromised patients, of whom 317 (84.7%) were receiving treatment for hematologic malignancies or solid tumors, at 28 intensive care units (ICUs) in France and Belgium between August 12, 2013, and January 2, 2015. INTERVENTIONS Patients were randomly assigned to early noninvasive ventilation (n = 191) or oxygen therapy alone (n = 183). MAIN OUTCOMES AND MEASURES The primary outcome was day-28 mortality. Secondary outcomes were intubation, Sequential Organ Failure Assessment score on day 3, ICU-acquired infections, duration of mechanical ventilation, and ICU length of stay. RESULTS At randomization, median oxygen flow was 9 L/min (interquartile range, 5-15) in the noninvasive ventilation group and 9 L/min (interquartile range, 6-15) in the oxygen group. All patients in the noninvasive ventilation group received the first noninvasive ventilation session immediately after randomization. On day 28 after randomization, 46 deaths (24.1%) had occurred in the noninvasive ventilation group vs 50 (27.3%) in the oxygen group (absolute difference, -3.2 [95% CI, -12.1 to 5.6]; P = .47). Oxygenation failure occurred in 155 patients overall (41.4%), 73 (38.2%) in the noninvasive ventilation group and 82 (44.8%) in the oxygen group (absolute difference, -6.6 [95% CI, -16.6 to 3.4]; P = .20). There were no significant differences in ICU-acquired infections, duration of mechanical ventilation, or lengths of ICU or hospital stays. CONCLUSIONS AND RELEVANCE Among immunocompromised patients admitted to the ICU with hypoxemic acute respiratory failure, early noninvasive ventilation compared with oxygen therapy alone did not reduce 28-day mortality. However, study power was limited. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT01915719.

Mechanical effects of airway humidification devices in difficult to wean patients.

ObjectiveTo evaluate the influence of airway humidification devices on the efficacy of ventilation in difficult to wean patients. DesignA prospective, randomized, controlled physiologic study. SettingA 22-bed medical intensive care unit in a university hospital. PatientsChronic respiratory failure patients. InterventionsPerformances of a heated humidifier and a heat and moisture exchanger were evaluated on diaphragmatic muscle activity, breathing pattern, gas exchange, and respiratory comfort during weaning from mechanical ventilation by using pressure support ventilation. Eleven patients with chronic respiratory failure were submitted to four pressure support ventilation sequences by using the heated humidifier and the heat and moisture exchanger at two different levels of pressure support ventilation (7 and 15 cm H2O). Measurement and Main ResultsCompared with the heated humidifier and regardless of the pressure support ventilation level used, the heat and moisture exchanger significantly increased all of the inspiratory effort variables (inspiratory work of breathing expressed in J/L and J/min, pressure time product, changes in esophageal pressure, and transdiaphragmatic pressure;p < .05) and dynamic intrinsic positive end-expiratory pressure (p < .05). Similarly, the heat and moisture exchanger produced a significant increase in Paco2 (p < .01) responsible for severe respiratory acidosis (p < .05), which was insufficiently compensated for despite a significant increase in minute ventilation (p < .05). This resulted in respiratory discomfort for all patients with the heat and moisture exchanger (p < .01). Adverse effects were partially counterbalanced by increasing the pressure support ventilation level with the heat and moisture exchanger by ≥8 cm H2O. ConclusionsThe type of airway humidification device used may negatively influence the mechanical efficacy of ventilation and, unless the pressure support ventilation level is considerably increased, the use of a heat and moisture exchanger should not be recommended in difficult or potentially difficult to wean patients with chronic respiratory failure.

Noninvasive ventilation and weaning in patients with chronic hypercapnic respiratory failure: a randomized multicenter trial.

RATIONALE The use of noninvasive ventilation (NIV) as an early weaning/extubation technique from mechanical ventilation remains controversial. OBJECTIVES To investigate NIV effectiveness as an early weaning/extubation technique in difficult-to-wean patients with chronic hypercapnic respiratory failure (CHRF). METHODS In 13 intensive care units, 208 patients with CHRF intubated for acute respiratory failure (ARF) who failed a first spontaneous breathing trial were randomly assigned to three groups: conventional invasive weaning group (n = 69), extubation followed by standard oxygen therapy (n = 70), or NIV (n = 69). NIV was permitted as rescue therapy for both non-NIV groups if postextubation ARF occurred. Primary endpoint was reintubation within 7 days after extubation. Secondary endpoints were: occurrence of postextubation ARF or death within 7 days after extubation, use of rescue postextubation NIV, weaning time, and patient outcomes. MEASUREMENTS AND MAIN RESULTS Reintubation rates were 30, 37, and 32% for invasive weaning, oxygen-therapy, and NIV groups, respectively (P = 0.654). Weaning failure rates, including postextubation ARF, were 54, 71, and 33%, respectively (P < 0.001). Rescue NIV success rates for invasive and oxygen-therapy groups were 45 and 58%, respectively (P = 0.386). By design, intubation duration was 1.5 days longer for the invasive group than in the two others. Apart from a longer weaning time in NIV than in invasive group (2.5 vs. 1.5 d; P = 0.033), no significant outcome difference was observed between groups. CONCLUSIONS No difference was found in the reintubation rate between the three weaning strategies. NIV decreases the intubation duration and may improve the weaning results in difficult-to-wean patients with CHRF by reducing the risk of postextubation ARF. The benefit of rescue NIV in these patients deserves confirmation.

Effects of pressure ramp slope values on the work of breathing during pressure support ventilation in restrictive patients.

OBJECTIVE To investigate, in restrictive patients, the influence of pressure ramp slope values on the efficacy of pressure support ventilation. DESIGN Prospective study. SETTING A university hospital medical intensive care unit. PATIENTS Twelve intubated restrictive patients. INTERVENTIONS Patients were randomly assigned to four sequences in which the values of the slope of the pressure ramp increase were modulated so that the plateau pressure was reached within a predetermined time: 0.1, 0.50, 1, or 1.50 secs. The more rapidly the pressure plateau was achieved, the higher was the initial flow rate. For convenience, these four different ventilatory settings were termed T 0.1, T 0.5, T 1, and T 1.5. MEASUREMENTS AND MAIN RESULTS We measured the following parameters 10 mins after application of each pressure ramp slope: inspiratory work of breathing, breathing pattern, and intrinsic PEEP (PEEPi). Work of breathing was evaluated using Campbells diagram, and expressed as a percentage of the values observed under spontaneous ventilation. A marked interindividual variation of the values for work of breathing was observed under spontaneous ventilation; the mean value for work of breathing was 1.97 +/- 0.82 joule/L, with a range of 1.22 to 4.10 joule/L. Comparison between the means for each sequence and each variable measured was performed by two-way analysis of variance with internal comparisons between sequences by Duncans test. Between the first (T 0.1) and the last (T 1.5) sequence, the reduction of values of the pressure ramp slope induced a progressive increase in the values for work of breathing, regardless of the mode of expression (in joule, joule/L, or joule/min). The values for work of breathing (joule/ L), expressed as a percentage of the values observed under spontaneous ventilation, increased from 44.2 +/- 14.4% to 78.3 +/- 17.8% (p < .001). In contrast, the reduction of the pressure ramp slope values and initial flow rate did not induce any significant change in tidal volume, respiratory frequency, and PEEPi. CONCLUSION Among the four tested slope values, the steepest was that which induced the lowest possible work of breathing in restrictive patients ventilated by pressure support ventilation. In this type of patient, we therefore suggest that the programmed pressure value should be reached by using a steep pressure ramp slope.

Noninvasive mechanical ventilation in clinical practice: A 2-year experience in a medical intensive care unit

ObjectiveTo evaluate the feasibility and outcome results of noninvasive mechanical ventilation (NIV) in daily clinical practice outside any prospective protocol-driven trial. DesignAn observational retrospective cohort study. SettingA 22-bed medical intensive care unit in a university hospital. PatientsA consecutive cohort of 124 patients who underwent 143 NIV trials, regardless of the indication, over two consecutive years (1997–1998). InterventionsNone. ResultsA total of 604 acute respiratory failure patients underwent mechanical ventilation, and 143 NIVs were performed in 124 patients. The overall prevalence of NIV use was 143 of 604 patients (24%) in three groups: hypoxemic acute respiratory failure (29.5%), hypercapnic acute respiratory failure (41%), and weaning/postextubation (29.5%). Intubation was avoided in 92 of 143 of the NIVs performed (64%), 19 (13%) after changing the initial NIV mode (i.e., a success rate of 62%, 51%, and 86% in the three groups, respectively). A total of 35 of 51 intubated patients (69%) required intubation during the first 24 hrs of NIV. Intensive care unit stay was 12 ± 10 days for the overall population, and mortality, when NIV failed, was 13 of 124 patients (10.5%). Arterial pH (p = .0527) and the Pao2/Fio2 ratio (p = .0482) after 1 hr were the only independent predictive factors for NIV failure by multivariate analysis. ConclusionsThis study confirms the results of controlled trials and demonstrates the feasibility and efficacy of NIV applied in daily clinical practice. These results suggest that NIV should be considered as a first-line ventilatory treatment in various etiologies of acute respiratory failure and as a promising weaning technique and postextubation ventilatory support. However, NIV should certainly be performed by a motivated and sufficiently trained care team.

Interface strategy during noninvasive positive pressure ventilation for hypercapnic acute respiratory failure

Objective:To assess the influence of initial mask choice on the clinical effectiveness and tolerance of noninvasive positive pressure ventilation (NIPPV) in the management of hypercapnic acute respiratory failure. Design:A prospective randomized controlled clinical study. Setting:A medical intensive care unit at a university hospital. Intervention:Randomization between two NIPPV interfaces. Patients:Initial mask choice was randomized between two standard masks: face (NIPPVf group) and nasal (NIPPVn group). The main end point was mask failure (i.e., mask change and/or intubation). Secondary end points were tolerance of NIPPV, change in respiratory parameters during the first 3 days, and patient outcome. Results were analyzed on an intent to treat basis. A per protocol analysis was also conducted. Main Results:Ninety patients with underlying chronic lung disease were included, 46 in the NIPPVf group and 44 in the NIPPVn group. The overall success rate of NIPPV was 83%. Mask failure occurred significantly more often in the NIPPVn group (32/44 vs. 9/46; p < 0.0001), mainly because of the need for mask change (32/44 vs. 0/46; p < 0.0001) because of the occurrence of major buccal air-leaks in 94% of cases. Improvement in respiratory parameters was similar in the two groups. Whereas air-leaks were more frequent in the NIPPVn group (p < 0.05), respiratory comfort was assessed as lower and complications more frequent by the staff in the NIPPVf group from day 2 (p < 0.05). Conclusions:A face mask should be the first-line strategy in the initial management of hypercapnic acute respiratory failure with NIPPV. However, if NIPPV has to be prolonged, switching to a nasal mask may improve comfort by reducing face mask complications.