Spontaneous breathing trial and post-extubation work of breathing in morbidly obese critically ill patients.

BACKGROUND: Predicting whether an obese critically ill patient can be successfully extubated may be specially challenging. Several weaning tests have been described but no physiological study has evaluated the weaning test that would best reflect the post-extubation inspiratory effort. METHODS: This was a physiological randomized crossover study in a medical and surgical single-center Intensive Care Unit, in patients with body mass index (BMI) >35 kg/m2 who were mechanically ventilated for more than 24 h and underwent a weaning test. After randomization, 17 patients were explored using five settings : pressure support ventilation (PSV) 7 and positive end-expiratory pressure (PEEP) 7 cmH2O; PSV 0 and PEEP 7cmH2O; PSV 7 and PEEP 0 cmH2O; PSV 0 and PEEP 0 cmH2O; and a T piece, and after extubation. To further minimize interaction between each setting, a period of baseline ventilation was performed between each step of the study. We hypothesized that the post-extubation work of breathing (WOB) would be similar to the T-tube WOB. RESULTS: Respiratory variables and esophageal and gastric pressure were recorded. Inspiratory muscle effort was calculated as the esophageal and trans-diaphragmatic pressure time products and WOB. Sixteen obese patients (BMI 44 kg/m2 ± 8) were included and successfully extubated. Post-extubation inspiratory effort, calculated by WOB, was 1.56 J/L ± 0.50, not statistically different from the T piece (1.57 J/L ± 0.56) or PSV 0 and PEEP 0 cmH2O (1.58 J/L ± 0.57), whatever the index of inspiratory effort. The three tests that maintained pressure support statistically underestimated post-extubation inspiratory effort (WOB 0.69 J/L ± 0.31, 1.15 J/L ± 0.39 and 1.09 J/L ± 0.49, respectively, p < 0.001). Respiratory mechanics and arterial blood gases did not differ between the five tests and the post-extubation condition. CONCLUSIONS: In obese patients, inspiratory effort measured during weaning tests with either a T-piece or a PSV 0 and PEEP 0 was not different to post-extubation inspiratory effort. In contrast, weaning tests with positive pressure overestimated post-extubation inspiratory effort. TRIAL REGISTRATION: Clinical trial.gov (reference NCT01616901 ), 2012, June 4th.

Sepsis is associated with a preferential diaphragmatic atrophy: a critically ill patient study using tridimensional computed tomography.

BACKGROUND: Diaphragm and psoas are affected during sepsis in animal models. Whether diaphragm or limb muscle is preferentially affected during sepsis in the critically ill remains unclear. METHODS: Retrospective secondary analysis study including 40 patients, comparing control (n = 17) and critically ill patients, with (n = 14) or without sepsis (n = 9). Diaphragm volume, psoas volume, and cross-sectional area of the skeletal muscles at the third lumbar vertebra were measured during intensive care unit (ICU) stay using tridimensional computed tomography scan volumetry. Diaphragm strength was evaluated using magnetic phrenic nerve stimulation. The primary endpoint was the comparison between diaphragm and peripheral muscle volume kinetics during the ICU stay among critically ill patients, with or without sepsis. RESULTS: Upon ICU admission, neither diaphragm nor psoas muscle volumes were significantly different between critically ill and control patients (163 ± 53 cm vs. 197 ± 82 cm for the diaphragm, P = 0.36, and 272 ± 116 cm vs. to 329 ± 166 cm for the psoas, P = 0.31). Twenty-five (15 to 36) days after admission, diaphragm volume decreased by 11 ± 13% in nonseptic and by 27 ± 12% in septic patients, P = 0.01. Psoas volume decreased by 11 ± 10% in nonseptic and by 19 ± 13% in septic patients, P = 0.09. Upon ICU admission, diaphragm strength was correlated with diaphragm volume and was lower in septic (6.2 cm H2O [5.6 to 9.3]) than that in nonseptic patients (13.2 cm H2O [12.3 to 15.6]), P = 0.01. CONCLUSIONS: During the ICU stay, both diaphragm and psoas volumes decreased. In septic patients, the authors report for the first time in humans preferential diaphragm atrophy compared with peripheral muscles.

Comparative evaluation of three interfaces for non-invasive ventilation: a randomized cross-over design physiologic study on healthy volunteers.

INTRODUCTION: Interface choice is crucial for non-invasive ventilation (NIV) success. We compared a new interface, the helmet next (HN), with the facial mask (FM) and the standard helmet (HS) in twelve healthy volunteers. METHODS: In this study, five NIV trials were randomly applied, preceded and followed by a trial of unassisted spontaneous breathing (SB). Baseline settings, for example, 5 cmH2O of both inspiratory pressure support (PS) and positive end-expiratory pressure (PEEP), were applied through FM, HS and HN, while increased settings (PS and PEEP of 8 cmH2O) were only applied through HS and HN. We measured flow, airway, esophageal and gastric pressures, and calculated inspiratory effort indexes and trigger delays. Comfort was assessed with a visual-analog-scale. RESULTS: We found that FM, HS and HN at baseline settings were not significantly different with respect to inspiratory effort indexes and comfort. Inspiratory trigger delay and time of synchrony (TI,synchrony) were significantly improved by FM compared to both helmets, whereas expiratory trigger delay was shorter with FM, as opposed to HS only. HN at increased settings performed better than FM in decreasing inspiratory effort measured by pressure-time product of transdiaphragmatic pressure (PTPdi)/breath (10.7 ± 9.9 versus 17.0 ± 11.0 cmH2Os), and PTPdi/min (128 ± 96 versus 204 ± 81 cmH2Os/min), and PTPdi/L (12.6 ± 9.9 versus 30.2 ± 16.8 cmH2Os/L). TI, synchrony was inferior between HN and HS at increased settings and FM. CONCLUSIONS: HN might hold some advantages with respect to interaction and synchrony between subject and ventilator, but studies on patients are needed to confirm these findings. TRIAL REGISTRATION: ClinicalTrials.gov NCT01610960.

Prospective randomized crossover study of a new closed-loop control system versus pressure support during weaning from mechanical ventilation.

BACKGROUND: Intellivent is a new full closed-loop controlled ventilation that automatically adjusts both ventilation and oxygenation parameters. The authors compared gas exchange and breathing pattern variability of Intellivent and pressure support ventilation (PSV). METHODS: In a prospective, randomized, single-blind design crossover study, 14 patients were ventilated during the weaning phase, with Intellivent or PSV, for two periods of 24 h in a randomized order. Arterial blood gases were obtained after 1, 8, 16, and 24 h with each mode. Ventilatory parameters were recorded continuously in a breath-by-breath basis during the two study periods. The primary endpoint was oxygenation, estimated by the calculation of the difference between the PaO2/FIO2 ratio obtained after 24 h of ventilation and the PaO2/FIO2 ratio obtained at baseline in each mode. The variability in the ventilatory parameters was also evaluated by the coefficient of variation (SD to mean ratio). RESULTS: There were no adverse events or safety issues requiring premature interruption of both modes. The PaO2/FIO2 (mean ± SD) ratio improved significantly from 245 ± 75 at baseline to 294 ± 123 (P = 0.03) after 24 h of Intellivent. The coefficient of variation of inspiratory pressure and positive end-expiratory pressure (median [interquartile range]) were significantly higher with Intellivent, 16 [11-21] and 15 [7-23]%, compared with 6 [5-7] and 7 [5-10]% in PSV. Inspiratory pressure, positive end-expiratory pressure, and FIO2 changes were adjusted significantly more often with Intellivent compared with PSV. CONCLUSIONS: Compared with PSV, Intellivent during a 24-h period improved the PaO2/FIO2 ratio in parallel with more variability in the ventilatory support and more changes in ventilation settings.

Neurally adjusted ventilatory assist in critically ill postoperative patients: a crossover randomized study.

BACKGROUND: Neurally adjusted ventilatory assist (NAVA) is a new mode of mechanical ventilation that delivers ventilatory assist in proportion to the electrical activity of the diaphragm. This study aimed to compare the ventilatory and gas exchange effects between NAVA and pressure support ventilation (PSV) during the weaning phase of critically ill patients who required mechanical ventilation subsequent to surgery. METHODS: Fifteen patients, the majority of whom underwent abdominal surgery, were enrolled. They were ventilated with PSV and NAVA for 24 h each in a randomized crossover order. The ventilatory parameters and gas exchange effects produced by the two ventilation modes were compared. The variability of the ventilatory parameters was also evaluated by the coefficient of variation (SD to mean ratio). RESULTS: Two patients failed to shift to NAVA because of postoperative bilateral diaphragmatic paralysis, and one patient interrupted the study because of worsening of his sickness. In the other 12 cases, the 48 h of the study protocol were completed, using both ventilation modes, with no signs of intolerance or complications. The Pao2/Fio2 (mean ± SD) ratio in NAVA was significantly higher than with PSV (264 ± 71 vs. 230 ± 75 mmHg, P < 0.05). Paco2 did not differ significantly between the two modes. The tidal volume (median [interquartile range]) with NAVA was significantly lower than with PSV (7.0 [6.4-8.6] vs. 6.5 [6.3-7.4] ml/kg predicted body weight, P < 0.05).Variability of insufflation airway pressure, tidal volume, and minute ventilation were significantly higher with NAVA than with PSV. Electrical activity of the diaphragm variability was significantly lower with NAVA than with PSV. CONCLUSIONS: Compared with PSV, respiratory parameter variability was greater with NAVA, probably leading in part to the significant improvement in patient oxygenation.

Adaptive support ventilation prevents ventilator-induced diaphragmatic dysfunction in piglet: an in vivo and in vitro study.

BACKGROUND: Contrary to adaptive support ventilation (ASV), prolonged totally controlled mechanical ventilation (CMV) results in the absence of diaphragm activity and causes ventilator-induced diaphragmatic dysfunction. Because maintaining respiratory muscles at rest is likely a major cause of ventilator-induced diaphragmatic dysfunction, ASV may prevent its occurrence in comparison with CMV. The aim of our study was to compare the effects of ASV with those of CMV on both in vivo and in vitro diaphragmatic properties. METHODS: Two groups of six anesthetized piglets were ventilated during a 72-h period. Piglets in the CMV group (n = 6) were ventilated without spontaneous ventilation, and piglets in the ASV group (n = 6) were ventilated with spontaneous breaths. Transdiaphragmatic pressure was measured after bilateral, supramaximal transjugular stimulation of the two phrenic nerves. A pressure-frequency curve was drawn after stimulation from 20 to 120 Hz of the phrenic nerves. Diaphragm fiber proportions and mean sectional area were evaluated. RESULTS: After 72 h of ventilation, transdiaphragmatic pressure decreased by 30% of its baseline value in the CMV group, whereas it did not decrease in the ASV group. Although CMV was associated with an atrophy of the diaphragm (evaluated by mean cross-sectional area of both the slow and fast myosin chains), atrophy was not detected in the ASV group. CONCLUSION: Maintaining diaphragmatic contractile activity by using the ASV mode may protect the diaphragm against the deleterious effect of prolonged CMV, as demonstrated both in vitro and in vivo, in healthy piglets.

Laparoscopic sleeve gastrectomy for late adolescent population.

BACKGROUND: Morbid obesity prevalence is rapidly increasing among adolescents worldwide. Evidence is mounting that bariatric surgery is the only reliable method for substantial and sustainable weight loss; however, the debate continues with regard to the optimal surgical procedure for adolescents and to the age limit when bariatric surgery should be proposed. METHODS: A retrospective multicenter review included all late adolescent patients (<20 years old) who underwent sleeve gastrectomy from 2005 to 2012 in three French bariatric centers: Montpellier University Hospital, Casamance Private Hospital, and Noumea Regional Hospital. Collected data included age, sex, body mass index (BMI), intraoperative complications, length of hospital stay, operative morbidity, the need for reoperation, and percentage of excess weight loss (% EWL) at 6 months, 1 year, and 2 years postoperatively. RESULTS: A total of 61 adolescent patients have undergone sleeve gastrectomy. Of these, 42 were women and 19 were men. The mean preoperative weight was 132.8 kg (range 90-217 kg) with a BMI of 46.7 (range 35.5-68.7). Seventeen patients (27.9%) were superobese (BMI > 50), and seven patients (11.5%) were supersuperobese (BMI > 60). All the procedures were performed by laparoscopy with no intraoperative complications. The mean hospital stay was 4.6 days. Four major complications were recorded: one staple line leak, two hematomas, and one case of pneumonia. No mortality was recorded. The % EWL at 6 months, 1 year, and 2 years postoperatively was 48.1% (±17.9%), 66.7% (±19.5%), and 78.4% (±16.8%), respectively, for a follow-up of 93.4, 81.9, and 52.4%, respectively. There were 18 patients (29.5%) with identified comorbid conditions: 10 cases of sleep apnea, 7 cases of hypertension, and 1 case of type 2 diabetes, with a resolution rate of 77.8%. CONCLUSIONS: Laparoscopic sleeve gastrectomy may be advantageous for this age group, since it involves neither foreign body placement nor lifelong malabsorption. Laparoscopic sleeve gastrectomy represents an attractive bariatric procedure for adolescent patients, more efficient than gastric banding and with less morbidity compared to gastric bypass.

Video laryngoscopy versus direct laryngoscopy for orotracheal intubation in the intensive care unit: a systematic review and meta-analysis.

PURPOSE: Single studies of video laryngoscopy (VL) use for airway management in intensive care unit (ICU) patients have produced controversial findings. The aim of this study was to critically review the literature to investigate whether VL reduces difficult orotracheal intubation (OTI) rate, first-attempt success, and complications related to intubation in ICU patients, compared to standard therapy, defined as direct laryngoscopy (DL). METHODS: We performed a systematic review and meta-analysis of randomized controlled trials, as well as prospective and retrospective observational studies, by searching PubMed, EMBASE, and bibliographies of articles retrieved. We screened for relevant studies that enrolled adults in whom the trachea was intubated in the ICU and compared VL to DL. We included studies reporting at least one clinical outcome of interest to perform a meta-analysis. We generated pooled odd ratios (OR) across studies. The primary outcome measure was difficult OTI. The secondary outcomes were first-attempt success, Cormack 3/4 grades, and complications related to intubation (severe hypoxemia, severe cardiovascular collapse, airway injury, esophageal intubation). RESULTS: Nine trials with a total of 2,133 participants (1,067 in DL and 1,066 in VL) were included in the current analysis. Compared to DL, VL reduced the risk of difficult OTI [OR 0.29 (95% confidence interval (CI) 0.20-0.44, p < 0.001)], Cormack 3/4 grades [OR 0.26 (95% CI 0.17-0.41, p < 0.001)], and esophageal intubation [0.14 (95% CI 0.02-0.81, p = 0.03)] and increased the first-attempt success [OR 2.07 (95% CI 1.35-3.16, p < 0.001)]. No statistically significant difference was found for severe hypoxemia, severe cardiovascular collapse or airway injury. CONCLUSIONS: These results suggest that VL could be useful in airway management of ICU patients.

Neurally adjusted ventilatory assist vs pressure support ventilation for noninvasive ventilation during acute respiratory failure: a crossover physiologic study.

BACKGROUND: Patient-ventilator asynchrony is common during noninvasive ventilation (NIV) with pressure support ventilation (PSV). We examined the effect of neurally adjusted ventilatory assist (NAVA) delivered through a facemask on synchronization in patients with acute respiratory failure (ARF). METHODS: This was a prospective, physiologic, crossover study of 13 patients with ARF (median Pa(O(2))/F(IO(2)), 196 [interquartile range (IQR), 142-225]) given two 30-min trials of NIV with PSV and NAVA in random order. Diaphragm electrical activity (EAdi), neural inspiratory time (T(In)), trigger delay (Td), asynchrony index (AI), arterial blood gas levels, and patient discomfort were recorded. RESULTS: There were significantly fewer asynchrony events during NAVA than during PSV (10 [IQR, 5-14] events vs 17 [IQR, 8-24] events, P = .017), and the occurrence of severe asynchrony (AI > 10%) was also less under NAVA (P = .027). Ineffective efforts and delayed cycling were significantly less with NAVA (P < .05 for both). NAVA was also associated with reduced Td (0 [IQR, 0-30] milliseconds vs 90 [IQR, 30-130] milliseconds, P < .001) and inspiratory time in excess (10 [IQR, 0-28] milliseconds vs 125 [IQR, 20-312] milliseconds, P < .001), but T(In) was similar under PSV and NAVA. The EAdi signal to its maximal value was higher during NAVA than during PSV ( P = .017). There were no significant differences in arterial blood gases or patient discomfort under PSV and NAVA. CONCLUSION: In view of specific experimental conditions, our comparison of PSV and NAVA indicated that NAVA significantly reduced severe patient-ventilator asynchrony and resulted in similar improvements in gas exchange during NIV for ARF. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT01426178; URL: www.clinicaltrials.gov.

A simple widespread computer help improves nutrition support orders and decreases infection complications in critically ill patients.

AIMS: To assess the impact of a simple computer-based decision-support system (computer help) on the quality of nutrition support orders and patients' outcome in Intensive-Care Unit (ICU). METHODS: This quality-improvement study was carried out in a 16-bed medical-surgical ICU in a French university hospital. All consecutive patients who stayed in ICU more than 10 days with non-oral feeding for more than 5 days were retrospectively included during two 12-month periods. Prescriptions of nutrition support were collected and compared to French national guidelines as a quality-improvement process. A computer help was constructed using a simple Excel-sheet (Microsoft(TM)) to guide physicians' prescriptions according to guidelines. This computer help was displayed in computers previously used for medical orders. Physicians were informed but no systematic protocol was implemented. Patients included during the first (control group) and second period (computer help group) were compared for achievement of nutrition goals and ICU outcomes. RESULTS: The control and computer help groups respectively included 71 and 95 patients. Patients' characteristics were not significantly different between groups. In the computer help group, prescriptions achieved significantly more often 80% of nutrition goals for calorie (45% vs. 79% p<0.001) and nitrogen intake (3% vs. 37%, p<0.001). Incidence of nosocomial infections decreased significantly between the two groups (59% vs. 41%, p = 0.03). Mortality did not significantly differ between control (21%) and computer help groups (15%, p = 0.30). CONCLUSIONS: Use of a widespread inexpensive computer help is associated with significant improvements in nutrition support orders and decreased nosocomial infections in ICU patients. This computer-help is provided in electronic supplement.

Implementation of a combo videolaryngoscope for intubation in critically ill patients: a before-after comparative study.

PURPOSE: Airway management in intensive care unit (ICU) patients is challenging. The main objective of this study was to compare the incidence of difficult laryngoscopy and/or difficult intubation between a combo videolaryngoscope and the standard Macintosh laryngoscope in critically ill patients. METHODS: In the context of the implementation of a quality-improvement process for airway management, we performed a prospective interventional monocenter before-after study which evaluated a new combo videolaryngoscope. The primary outcome was the incidence of difficult laryngoscopy (defined by Cormack grade 3-4) and/or difficult intubation (more than two attempts). The secondary outcomes were the severe life-threatening complications related to intubation in ICU and the rate of difficult intubation in cases of predicted difficult intubation evaluated by a specific score (MACOCHA score ≥3). RESULTS: Two hundred and ten non-selected consecutive intubation procedures were included, 140 in the standard laryngoscope group and 70 in the combo videolaryngoscope group. The incidence of difficult laryngoscopy and/or difficult intubation was 16 % in the laryngoscope group vs. 4 % in the combo videolaryngoscope group (p = 0.01). The severe life-threatening complications related to intubation did not differ between groups (16 vs. 14 %, p = 0.79). Among the 32 patients with a MACOCHA score ≥3, there were significantly more patients with difficult intubation in the standard laryngoscope group in comparison to the combo videolaryngoscope group [12/23 (57 %) vs. 0/9 (0 %), p < 0.01]. CONCLUSIONS: The systematic use of a combo videolaryngoscope in ICU was associated with a decreased incidence of difficult laryngoscopy and/or difficult intubation.

Cytomegalovirus and herpes simplex virus effect on the prognosis of mechanically ventilated patients suspected to have ventilator-associated pneumonia.

OBJECTIVE: Cytomegalovirus (CMV) and herpes simplex virus (HSV) are common viruses that can affect critically ill patients who are not immunocompromised. The aim of this study was to determine whether the identification of CMV and/or HSV in mechanically ventilated critically ill patients suspected of having pneumonia was associated with an increased mortality. DESIGN: Prospective epidemiological study. SETTING: Medical intensive care unit of a tertiary medical center. PATIENTS: Ninety-three patients with suspected pneumonia. INTERVENTIONS: Patients with suspected pneumonia had bronchoalveolar lavage and blood samples taken to confirm the diagnosis. Antigenemia was used to detect CMV in the blood. Bronchoalveolar lavage samples were submitted to testing using quantitative real-time Polymerase Chain Reaction. MEASUREMENTS AND MAIN RESULTS: We identified 22 patients with a CMV infection, 26 patients with an HSV infection and 45 patients without CMV or HSV infection (control group). Mortality at day 60 was higher in patients with a CMV infection than in patients from the control group (55% vs. 20%, P<0.01). Mortality at day 60 was not significantly increased in the group with HSV infection. Duration of ICU stay and ICU mortality were significantly higher in patients with CMV infections when compared to patients from the control group, whereas ventilator free days were significantly lower in patients with CMV infections when compared to patients from the control group. CONCLUSIONS: In critically ill patients, a CMV infection is associated with an increased mortality. Further interventional studies are needed to evaluate whether treatment could improve the prognosis.