Erwan L'Her

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.

Acquiring procedural skills in ICUs: a prospective multicenter study*.

Objectives:Providing appropriate training of procedural skills to residents while ensuring patient safety through trainee supervision is a difficult and constant challenge. We sought to determine how effective and safe procedural skill acquisition is in French ICUs and to identify failure and complication risk factors. Design:Multicenter prospective observational study. Invasive procedures performed by residents were recorded during two consecutive semesters. Setting:Eighty-four residents. Subjects:Eighty-four residents. Intervention:None. Measurements and Main Results:Number of invasive procedures performed, failure and complication rates, supervision, and assistance provided. Five thousand six hundred seventeen procedures were prospectively studied: 1,007 tracheal intubations, 1,272 arterial and 2,586 central venous catheter insertions, 457 fiberoptic bronchoscopies, and 295 chest tube insertions. During the semesters, residents performed a median of 10 intubations, 14 arterial catheter insertions, and 26 central venous catheter insertions. Complication rates were low, similar to those in the literature: 8.6% desaturation and 7.4% esophageal placement during intubation; 0.4% and 2.3% pneumothorax with jugular and subclavian central venous catheter insertions, respectively. We identified risk factors for failure and complications. Higher rates of failure and complications for intubation were associated with residents with no or little previous experience (p < 0.001); failure of internal jugular vein catheterization was associated with left-side insertion (p = 0.005) and absence of mechanical ventilation (p = 0.007). Supervision and assistance were more frequent at the beginning of the semester and for intubation and chest tube insertion. Finally, residents had less access to fiberoptic bronchoscopy and chest tube insertion. Conclusion:Procedural skills acquisition by residents in the ICU appears feasible and safe with complication rates comparable to what has previously been reported. We identified specific procedures and situations associated with higher failure and complication rates that could require proactive training. Questions still remain regarding minimal numbers of procedures to attain competence and how best to provide procedural training.

Optimal Oxygen Titration in Patients with Chronic Obstructive Pulmonary Disease: A Role for Automated Oxygen Delivery?

Oxygen therapy can be life-saving for patients with chronic obstructive pulmonary disease (COPD) and is the backbone of any acute COPD treatment strategy. Although largely considered to be a benign drug, many publications have highlighted the need to accurately adjust oxygen delivery to avoid both hypoxemia and the problem of hyperoxia-induced hypercapnia. Recent clinical data have shown that the deleterious effects of excess oxygen treatment can not only alter carbon dioxide levels (which has been known for more than 60 years) but can also lead to an increase in mortality. Nevertheless, despite the extensive literature, the risks associated with hyperoxia are often overlooked and published clinical recommendations are largely ignored. This failure in knowledge translation has become increasingly important not only because of the desire to reduce medical error, but in a society with limited health care resources, the economic burden of COPD is such that it cannot afford to make preventable medical mistakes. Recently, novel devices have been developed to automatically adjust oxygen flow rates to maintain stable oxygen saturations. These closed-loop oxygen delivery systems have the potential to reduce medical error, improve morbidity and mortality, and reduce health care costs. Preliminary data in this field are promising and will require a significant amount of research in the coming years to determine the precise indications for these systems. The importance of appropriate oxygen dosing and the current literature regarding novel oxygen delivery systems are reviewed.

Bench-test comparison of 26 emergency and transport ventilators

IntroductionNumerous emergency and transport ventilators are commercialized and new generations arise constantly. The aim of this study was to evaluate a large panel of ventilators to allow clinicians to choose a device, taking into account their specificities of use.MethodsThis experimental bench-test took into account general characteristics and technical performances. Performances were assessed under different levels of FIO2 (100%, 50% or Air-Mix), respiratory mechanics (compliance 30,70,120 mL/cmH2O; resistance 5,10,20 cmH2O/mL/s), and levels of leaks (3.5 to 12.5 L/min), using a test lung.ResultsIn total 26 emergency and transport ventilators were analyzed and classified into four categories (ICU-like, n = 5; Sophisticated, n = 10; Simple, n = 9; Mass-casualty and military, n = 2). Oxygen consumption (7.1 to 15.8 L/min at FIO2 100%) and the Air-Mix mode (FIO2 45 to 86%) differed from one device to the other. Triggering performance was heterogeneous, but several sophisticated ventilators depicted triggering capabilities as efficient as ICU-like ventilators. Pressurization was not adequate for all devices. At baseline, all the ventilators were able to synchronize, but with variations among respiratory conditions. Leak compensation in most ICU-like and 4/10 sophisticated devices was able to correct at least partially for system leaks, but with variations among ventilators.ConclusionMajor differences were observed between devices and categories, either in terms of general characteristics or technical reliability, across the spectrum of operation. Huge variability of tidal volume delivery with some devices in response to modifications in respiratory mechanics and FIO2 should make clinicians question their use in the clinical setting.

Automated oxygen titration and weaning with FreeO 2 in patients with acute exacerbation of COPD: a pilot randomized trial

Introduction We developed a device (FreeO2) that automatically adjusts the oxygen flow rates based on patients’ needs, in order to limit hyperoxia and hypoxemia and to automatically wean them from oxygen. Objective The aim of this study was to evaluate the feasibility of using FreeO2 in patients hospitalized in the respiratory ward for an acute exacerbation of COPD. Methods We conducted a randomized controlled trial comparing FreeO2 vs manual oxygen titration in the respiratory ward of a university hospital. We measured the perception of appropriateness of oxygen titration and monitoring in both groups by nurses and attending physicians using a Likert scale. We evaluated the time in the target range of oxygen saturation (SpO2) as defined for each patient by the attending physician, the time with severe desaturation (SpO2 <85%), and the time with hyperoxia (SpO2 >5% above the target). We also recorded length of stay, intensive care unit admissions, and readmission rate. Fifty patients were randomized (25 patients in both groups; mean age: 72±8 years; mean forced expiratory volume in 1 second: 1.00±0.49 L; and mean initial O2 flow 2.0±1.0 L/min). Results Nurses and attending physicians felt that oxygen titration and monitoring were equally appropriate with both O2 administration systems. The percentage of time within the SpO2 target was significantly higher with FreeO2, and the time with severe desaturation and hyperoxia was significantly reduced with FreeO2. Time from study inclusion to hospital discharge was 5.8±4.4 days with FreeO2 and 8.4±6.0 days with usual oxygen administration (P=0.051). Conclusion FreeO2 was deemed as an appropriate oxygen administration system by nurses and physicians of a respiratory unit. This system maintained SpO2 at the target level better than did manual titration and reduced periods of desaturation and hyperoxia. Our results also suggest that FreeO2 has the potential to reduce the hospital length of stay.

Comparison of usual and alternative methods to measure height in mechanically ventilated patients: potential impact on protective ventilation

BACKGROUND: Protective ventilation implementation requires the calculation of predicted body weight (PBW), determined by a formula based on gender and height. Consequently, height inaccuracy may be a limiting factor to correctly set tidal volumes. The objective of this study was to evaluate the accuracy of different methods in measuring heights in mechanically ventilated patients. METHODS: Before cardiac surgery, actual height was measured with a height gauge while subjects were standing upright (reference method); the height was also estimated by alternative methods based on lower leg and forearm measurements. After cardiac surgery, upon ICU admission, a subjects height was visually estimated by a clinician and then measured with a tape measure while the subject was supine and undergoing mechanical ventilation. RESULTS: One hundred subjects (75 men, 25 women) were prospectively included. Mean PBW was 61.0 ± 9.7 kg, and mean actual weight was 30.3% higher. In comparison with the reference method, estimating the height visually and using the tape measure were less accurate than both lower leg and forearm measurements. Errors above 10% in calculating the PBW were present in 25 and 40 subjects when the tape measure or visual estimation of height was used in the formula, respectively. With lower leg and forearm measurements, 15 subjects had errors above 10% (P < .001). CONCLUSIONS: Our results demonstrate that significant variability exists between the different methods used to measure height in bedridden patients on mechanical ventilation. Alternative methods based on lower leg and forearm measurements are potentially interesting solutions to facilitate the accurate application of protective ventilation.

Intensive care medical procedures are more complicated, more stressful, and less comfortable with Ebola personal protective equipment: A simulation study

Ebola virus disease (EVD) is a life-threatening condition. Appropriate management of organ failure, hemodynamic instability, and metabolic disorders significantly improves survival. This implies that life-saving procedures are undertaken in case of need, including endotracheal intubation, nasogastric tube placement and central venous catheter (CVC) insertion. The challenge is to provide high quality of care to patients with life-threatening EVD, under optimal safety conditions for health care workers, i.e. with reinforced personal protective equipment (PPE), ensuring that no exposure to patient blood or any other body fluid occur.1, 2 and 3 We assessed the impact of Ebola PPE use on the performance of senior ICU physicians during common intensive care unit (ICU) procedures, and on the workload, in a simulation environment...

Automatic versus manual oxygen administration in the emergency department

Oxygen is commonly administered in hospitals, with poor adherence to treatment recommendations. We conducted a multicentre randomised controlled study in patients admitted to the emergency department requiring O2 ≥3 L·min−1. Patients were randomised to automated closed-loop or manual O2 titration during 3 h. Patients were stratified according to arterial carbon dioxide tension (PaCO2) (hypoxaemic PaCO2≤45 mmHg; or hypercapnic PaCO2>45–≤55 mmHg) and study centre. Arterial oxygen saturation measured by pulse oximetry (SpO2) goals were 92–96% for hypoxaemic, or 88–92% for hypercapnic patients. Primary outcome was % time within SpO2 target. Secondary endpoints were hypoxaemia and hyperoxia prevalence, O2 weaning, O2 duration and hospital length of stay. 187 patients were randomised (93 automated, 94 manual) and baseline characteristics were similar between the groups. Time within the SpO2 target was higher under automated titration (81±21% versus 51±30%, p<0.001). Time with hypoxaemia (3±9% versus 5±12%, p=0.04) and hyperoxia under O2 (4±9% versus 22±30%, p<0.001) were lower with automated titration. O2 could be weaned at the end of the study in 14.1% versus 4.3% patients in the automated and manual titration group, respectively (p<0.001). O2 duration during the hospital stay was significantly reduced (5.6±5.4 versus 7.1±6.3 days, p=0.002). Automated O2 titration in the emergency department improved oxygenation parameters and adherence to guidelines, with potential clinical benefits. Automated oxygen titration is superior to manual administration in terms of time within oxygenation targets http://ow.ly/pgWC30c2sLv

Mechanical ventilation system monitoring: Automatic detection of dynamic hyperinflation and asynchrony

Automatic monitoring of mechanical ventilation system becomes more and more important with respect to the number of patients per clinician. In this paper, the automatic detections of dynamic hyperinflation (PEEPi) and asynchrony in a monitoring framework are considered. The proposed detection methods are based on a robust non-parametric hypothesis testing, namely Random Distortion Testing (RDT), that requires no prior information on the signal distribution. The experiment results have shown that the proposed algorithms provide relevant detection of abnormalities during mechanical ventilation.

Patient-ventilator asynchrony: Automatic detection of AutoPEEP

This paper introduces a method to automatically detect AutoPEEP (pulmonary distension), a frequent asynchrony in the patient-ventilator interface. The detection algorithm is developed based on a robust non-parametric hypothesis testing that requires no prior information on the distribution of the signal. The experiment results have shown that the proposed algorithm provide relevant AutoPEEP detection on both simulated and real data.