Mechanical Ventilation after Traumatic Spinal Cord Injury-A Multicentric Cohort Study-based Prediction Model for Weaning Success: The BICYCLE Score.

Rationale: Limited information exists about the epidemiology, outcomes, and predictors of weaning from mechanical ventilation in patients with spinal cord injury. Objectives: Our aim was to investigate predictors of weaning outcomes for patients with traumatic spinal cord injury (tSCI) and develop and validate a prognostic model and score for weaning success. Methods: This was a registry-based, multicentric cohort study including all adult patients with tSCI requiring mechanical ventilation (MV) and admitted to one of the intensive care units (ICUs) of the Trauma Registry at St. Michael's Hospital (Toronto, ON, Canada) and the Canadian Rick Hansen Spinal Cord Injury Registry between 2005 and 2019. The primary outcome was weaning success from MV at ICU discharge. Secondary outcomes included weaning success at Days 14 and 28, time to liberation from MV accounting for competing risk of death, and ventilator-free days at 28 and 60 days. Associations between baseline characteristics and weaning success or time to liberation from MV were measured using multivariable logistic and competing risk regressions. A parsimonious model to predict weaning success and ICU discharge was developed and validated via bootstrap. A prediction score for weaning success at ICU discharge was derived, and its discriminative ability was assessed using receiver operating characteristic curve analysis and compared with the Injury Severity Score (ISS). Results: Of 459 patients analyzed, 246 (53.6%), 302 (65.8%), and 331 (72.1%) were alive and free of MV at Day 14, Day 28, and ICU discharge, respectively; 54 (11.8%) died in the ICU. Median time to liberation from MV was 12 days. Factors associated with weaning success were Blunt injury (odds ratio [OR], 2.96; P = 0.010), ISS (OR, 0.98; P = 0.025), Complete syndrome (OR, 0.53; P = 0.009), age in Years (OR, 0.98; P = 0.003), and Cervical LEsion (OR, 0.60; P = 0.045). The BICYCLE score showed a greater area under the curve than the ISS (0.689 [95% confidence interval (CI), 0.631-0.743] vs. 0.537 [95% CI, 0.479-0.595]; P < 0.0001). Factors predicting weaning success also predicted time to liberation. Conclusions: In a large multicentric cohort, 72% of patients with tSCI were weaned and discharged alive from the ICU. Readily available admission characteristics can reasonably predict weaning success and help prognostication.

Mechanical Ventilation in ARDS With an Automatic Resuscitator.

BACKGROUND: The Oxylator is an automatic resuscitator, powered only by an oxygen cylinder with no electricity required, that could be used in acute respiratory failure in situations in which standard mechanical ventilation is not available or feasible. We aimed to assess the feasibility and safety of mechanical ventilation by using this automatic resuscitator in an animal model of ARDS. METHODS: A randomized experimental study in a porcine ARDS model with 12 pigs randomized to the Oxylator group or the control group (6 per group) and ventilated for 4 h. In the Oxylator group, peak pressure was set at 20 cm H2O and PEEP was set at the lowest observed breathing frequency during a decremental PEEP titration. The control pigs were ventilated with a conventional ventilator by using protective settings and PEEP at the crossing point of collapse and overdistention, as indicated by electrical impedance tomography. Our end points were feasibility and safety as well as respiratory mechanics, gas exchange, and hemodynamics. RESULTS: After lung injury, the mean ± SD respiratory system compliance and PaO2 /FIO2 were 13 ± 2 mL/cm H2O and 61 ± 17 mm Hg, respectively. The mean ± SD total PEEP was 10 ± 2 cm H2O and 13 ± 2 cm H2O in the control and Oxylator groups, respectively (P = .046). The mean plateau pressure was kept to < 30 cm H2O in both groups. In the Oxylator group, the tidal volume was transiently > 8 mL/kg but was 6 ± 0.4 mL/kg at 4 h, whereas the breathing frequency increased from 38 ± 4 to 48 ± 3 breaths/min (P < .001). There was no difference in driving pressure, compliance, PaO2 /FIO2 , and pulmonary shunt between the groups. The mean ± SD PaCO2 was higher in the Oxylator group after 4 h, 74 ± 9 mm Hg versus 58 ± 6 mm Hg (P < .001). There were no differences in hemodynamics between the groups, including blood pressure and cardiac output. CONCLUSIONS: Short-term mechanical ventilation by using an automatic resuscitator and a fixed pressure setting in an ARDS animal model was feasible and safe.

High Flow Nasal Cannula compared to Continuous Positive Airway Pressure: a bench and physiological study.

High-flow nasal cannula (HFNC) is extensively used for acute respiratory failure. However, questions remain regarding its physiological effects. We explored 1) whether HFNC produced similar effects to continuous positive airway pressure (CPAP); 2) possible explanations of respiratory rate changes; 3) the effects of mouth opening. Two studies were conducted: a bench study using a manikin's head with lungs connected to a breathing simulator while delivering HFNC flow rates from 0 to 60L/min; a physiological cross-over study in 10 healthy volunteers receiving HFNC (20 to 60L/min) with the mouth open or closed and CPAP 4cmH2O delivered through face-mask. Nasopharyngeal and esophageal pressures were measured; tidal volume and flow were estimated using calibrated electrical impedance tomography. In the bench study, nasopharyngeal pressure at end-expiration reached 4cmH2O with HFNC at 60L/min, while tidal volume decreased with increasing flow. In volunteers with HFNC at 60L/min, nasopharyngeal pressure reached 6.8cmH2O with mouth closed and 0.8cmH2O with mouth open; p<0.001. When increasing HFNC flow, respiratory rate decreased by lengthening expiratory time, tidal volume did not change, and effort decreased (pressure-time product of the respiratory muscles); at 40L/min, effort was equivalent between CPAP and HFNC40L/min and became lower at 60L/min (p=0.045). During HFNC with mouth closed, and not during CPAP, resistance to breathing was increased, mostly during expiration. In conclusion, mouth closure during HFNC induces a positive nasopharyngeal pressure proportional to flow rate and an increase in expiratory resistance that might explain the prolonged expiration and reduction in respiratory rate and effort, and contribute to physiological benefits.

Separation from mechanical ventilation and survival after spinal cord injury: a systematic review and meta-analysis.

BACKGROUND: Prolonged need for mechanical ventilation greatly impacts life expectancy of patients after spinal cord injury (SCI). Weaning outcomes have never been systematically assessed. In this systematic review and meta-analysis, we aimed to investigate the probability of weaning success, duration of mechanical ventilation, mortality, and their predictors in mechanically ventilated patients with SCI. METHODS: We searched six databases from inception until August 2021 for randomized-controlled trials and observational studies enrolling adult patients (≥ 16 years) with SCI from any cause requiring mechanical ventilation. Titles and abstracts were screened independently by two reviewers. Full texts of the identified articles were then assessed for eligibility. Data were extracted independently and in duplicate by pairs of authors, using a standardized data collection form. Synthetic results are reported as meta-analytic means and proportions, based on random effects models. RESULTS: Thirty-nine studies (14,637 patients, mean age 43) were selected. Cervical lesions were predominant (12,717 patients had cervical lesions only, 1843 in association with other levels' lesions). Twenty-five studies were conducted in intensive care units (ICUs), 14 in rehabilitative settings. In ICU, the mean time from injury to hospitalization was 8 h [95% CI 7-9], mean duration of mechanical ventilation 27 days [20-34], probability of weaning success 63% [45-78] and mortality 8% [5-11]. Patients hospitalized in rehabilitation centres had a greater number of high-level lesions (C3 or above), were at 40 days [29-51] from injury and were ventilated for a mean of 97 days [65-128]; 82% [70-90] of them were successfully weaned, while mortality was 1% [0-19]. CONCLUSIONS: Although our study highlights the lack of uniform definition of weaning success, of clear factors associated with weaning outcomes, and of high-level evidence to guide optimal weaning in patients with SCI, it shows that around two-thirds of mechanically ventilated patients can be weaned in ICU after SCI. A substantial gain in weaning success can be obtained during rehabilitation, with additional duration of stay but minimal increase in mortality. The study is registered with PROSPERO (CRD42020156788).

Abdominal Muscle Use During Spontaneous Breathing and Cough in Patients Who Are Mechanically Ventilated: A Bi-center Ultrasound Study.

BACKGROUND: Ultrasound may be useful to assess the structure, activity, and function of the abdominal muscles in patients who are mechanically ventilated. RESEARCH QUESTION: Does measurement of abdominal muscle thickening on ultrasound in patients who are mechanically ventilated provide clinically relevant information about abdominal muscle function and weaning outcomes? STUDY DESIGN AND METHODS: This study consisted of two parts, a physiological study conducted in healthy subjects and a prospective observational study in patients who were mechanically ventilated. Abdominal muscle thickness and thickening fraction were measured during cough and expiratory efforts in 20 healthy subjects, and prior to and during a spontaneous breathing trial in 57 patients being ventilated. RESULTS: In healthy subjects, internal oblique and rectus abdominis thickening fraction correlated with pressure generated during expiratory efforts (P < .001). In patients being ventilated, abdominal muscle thickness and thickening fraction were feasible to measure in all patients, and reproducibility was moderately acceptable. During a failed spontaneous breathing trial, thickening fraction of transversus abdominis and internal oblique increased substantially from baseline (13.2% [95% CI, 0.9-24.8] and 7.2% [95% CI, 2.2-13.2], respectively). The combined thickening fraction of transversus abdominis, internal oblique, and rectus abdominis measured during cough was associated with an increased risk of reintubation or reconnection to the ventilator following attempted liberation (OR, 2.1; 95% CI, 1.1-4.4 per 10% decrease in thickening fraction). INTERPRETATION: Abdominal muscle thickening on ultrasound was correlated to the airway pressure generated by expiratory efforts. In patients who were mechanically ventilated, abdominal muscle ultrasound measurements are feasible and moderately reproducible. Among patients who passed a spontaneous breathing trial, reduced abdominal muscle thickening during cough was associated with a high risk of liberation failure. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov; No.: NCT03567564; URL: www.clinicaltrials.gov.

The COVID-19 Worsening Score (COWS)-a predictive bedside tool for critical illness.

OBJECTIVES: To evaluate the accuracy of a new COVID-19 prognostic score based on lung ultrasound (LUS) and previously validated variables in predicting critical illness. METHODS: We conducted a single-center retrospective cohort development and internal validation study of the COVID-19 Worsening Score (COWS), based on a combination of the previously validated COVID-GRAM score (GRAM) variables and LUS. Adult COVID-19 patients admitted to the emergency department (ED) were enrolled. Ten variables previously identified by GRAM, days from symptom onset, LUS findings, and peripheral oxygen saturation/fraction of inspired oxygen (P/F) ratio were analyzed. LUS score as a single predictor was assessed. We evaluated GRAM model's performance, the impact of adding LUS, and then developed a new model based on the most predictive variables. RESULTS: Among 274 COVID-19 patients enrolled, 174 developed critical illness. The GRAM score identified 51 patients at high risk of developing critical illness and 132 at low risk. LUS score over 15 (range 0 to 36) was associated with a higher risk ratio of critical illness (RR, 2.05; 95% confidence interval [CI], 1.52-2.77; area under the curve [AUC], 0.63; 95% CI 0.676-0.634). The newly developed COVID-19 Worsening Score relies on five variables to classify high- and low-risk patients with an overall accuracy of 80% and negative predictive value of 93% (95% CI, 87%-98%). Patients scoring more than 0.183 on COWS showed a RR of developing critical illness of 8.07 (95% CI, 4.97-11.1). CONCLUSIONS: COWS accurately identify patients who are unlikely to need intensive care unit (ICU) admission, preserving resources for the remaining high-risk patients.

A Gas-Powered, Patient-Responsive Automatic Resuscitator for Use in Acute Respiratory Failure: A Bench and Experimental Study.

BACKGROUND: During the COVID-19 pandemic, a need for innovative, inexpensive, and simple ventilator devices for mass use has emerged. The Oxylator (CPR Medical Devices, Markham, Ontario, Canada) is an FDA-approved, fist-size, portable ventilation device developed for out-of-hospital emergency ventilation. It has not been tested in conditions of severe lung injury or with added PEEP. We aimed to assess the performance and reliability of the device in simulated and experimental conditions of severe lung injury, and to derive monitoring methods to allow the delivery of safe, individualized ventilation during situations of surge. METHODS: We bench-tested the functioning of the device with an added PEEP valve extensively, mimicking adult patients with various respiratory mechanics during controlled ventilation, spontaneous breathing, and prolonged unstable conditions where mechanics or breathing effort was changed at every breath. The device was further tested on a porcine model (4 animals) after inducing lung injury, and these results were compared with conventional ventilation modes. RESULTS: The device was stable and predictable, delivering a constant flow (30 L/min) and cycling automatically at the inspiratory pressure set (minimum of 20 cm H2O) above auto-PEEP. Changes in respiratory mechanics manifested as changes in respiratory timing, allowing prediction of tidal volumes from breathing frequency. Simulating lung injury resulted in relatively low tidal volumes (330 mL with compliance of 20 mL/cm H2O). In the porcine model, arterial oxygenation, CO2, and pH were comparable to conventional modes of ventilation. CONCLUSIONS: The Oxylator is a simple device that delivered stable ventilation with tidal volumes within a clinically acceptable range in bench and porcine lung models with low compliance. External monitoring of respiratory timing is advisable, allowing tidal volume estimation and recognition of changes in respiratory mechanics. The device can be an efficient, low-cost, and practical rescue solution for providing short-term ventilatory support as a temporary bridge, but it requires a caregiver at the bedside.

Diaphragmatic thickening fraction as a potential predictor of response to continuous positive airway pressure ventilation in Covid-19 pneumonia: A single-center pilot study.

BACKGROUND: In a variable number of Covid-19 patients with acute respiratory failure, non-invasive breathing support strategies cannot provide adequate oxygenation, thus making invasive mechanical ventilation necessary. Factors predicting this unfavorable outcome are unknown, but we hypothesized that diaphragmatic weakness may contribute. METHODS: We prospectively analyzed the data of 27 consecutive patients admitted to the general Intensive Care Unit (ICU) from March 19, 2020, to April 20, 2020 and submitted to continuous positive airway pressure (CPAP) before considering invasive ventilation. Diaphragmatic thickening fraction (DTF) inferred by ultrasound was determined before applying CPAP. RESULTS: Eighteen patients recovered with CPAP, whereas nine required invasive mechanical ventilation with longer stay in ICU (p < 0.001) and hospital (p = 0.003). At univariate logistic regression analysis, CPAP failure was significantly associated with low DTF [ß: -0.396; OR: 0.673; p < 0.001] and high respiratory rate [ß: 0.452; OR: 1.572; p < 0.001] but only DTF reached statistical significance at multivariate analysis [ß: -0.384; OR: 0.681; p < 0.001]. The DTF best threshold predicting CPAP failure was 21.4 % (AUC: 0.944; sensitivity: 94.4 %, specificity: 88.9 %). CONCLUSIONS: In critically ill patients with Covid-19 respiratory failure admitted to ICU, a reduced DTF could be a potential predictor of CPAP failure and requirement of invasive ventilation.

The role of lung ultrasonography in COVID-19 disease management.

Coronavirus disease 2019 (COVID-19) has created unprecedented disruption for global healthcare systems. Offices and emergency departments (EDs) were the first responders to the pandemic, followed by medical wards and intensive care unit (ICUs). Worldwide efforts sprouted to coordinate proper response by increasing surge capacity and optimizing diagnosis and containment. Within the complex scenario of the outbreak, the medical community shared scientific research and implemented best-guess imaging strategies in order to save time and additional staff exposures. Early publications showed agreement between chest computed tomography (CT) and lung sonography: widespread ground-glass findings resembling acute respiratory distress syndrome (ARDS) on CT of COVID-19 patients matched lung ultrasound signs and patterns. Well-established accuracy of bedside sonography for lung conditions and its advantages (such as no ionizing radiation; low-cost, real-time bedside imaging; and easier disinfection steps) prompted a wider adoption of lung ultrasound for daily assessment and monitoring of COVID-19 patients. Growing literature, webinars, online materials, and international networks are promoting lung ultrasound for the same purpose. We propose 11 lung ultrasound roles for different medical settings during the pandemic, starting from the out-of-hospital setting, where lung ultrasound has ergonomic and infection control advantages. Then we describe how medical wards and ICUs can safely integrate lung ultrasound into COVID-19 care pathways. Finally, we present outpatient use of lung ultrasound to aid follow-up of positive case contacts and of those discharged from the hospital.

ERS International Congress, Madrid, 2019: highlights from the Respiratory Intensive Care Assembly.

The Respiratory Intensive Care Assembly of the European Respiratory Society is delighted to present the highlights from the 2019 International Congress in Madrid, Spain. We have selected four sessions that discussed recent advances in a wide range of topics: from acute respiratory failure to cough augmentation in neuromuscular disorders and from extra-corporeal life support to difficult ventilator weaning. The subjects are summarised by early career members in close collaboration with the Assembly leadership. We aim to give the reader an update on the most important developments discussed at the conference. Each session is further summarised into a short list of take-home messages.

Noninvasive ventilation during weaning from prolonged mechanical ventilation.

BACKGROUND AND OBJECTIVE: Non invasive ventilation (NIV) is currently employed for weaning from invasive ventilation (IMV) in the acute setting but its use for weaning from prolonged ventilation is still occasional and not standardized. We wanted to evaluate whether a combined protocol of NIV and decannulation in tracheostomized patients needing prolonged mechanical ventilation was feasible and what would be the one-year outcome. METHODS: We studied patients still dependent from invasive mechanical ventilation with the following inclusion criteria: a) tolerance of at least 8h of unsupported breathing, b) progressive hypercapnia/acidosis after invasive ventilation discontinuation, c) good adaptation to NIV, d) favorable criteria for decannulation. These patients were switched from IMV to NIV and decannulated; then they were discharged on home NIV and followed-up for one year in order to evaluate survival and complications rate. RESULTS: Data from patients consecutively admitted to a weaning unit were prospectively collected between 2005 and 2018. Out of 587 patients admitted over that period, 341 were liberated from prolonged mechanical ventilation. Fifty-one out of 147 unweaned patients (35%) were eligible for the protocol but only 46 were enrolled. After a mean length of stay of 35 days they were decannulated and discharged on domiciliary NIV. After one year, 38 patients were still alive (survival rate 82%) and 37 were using NIV with good adherence (only one patient was switched again to invasive ventilation). CONCLUSIONS: NIV applied to patients with failed weaning from prolonged IMV is feasible and can facilitate the decannulation process. Patients successfully completing this process show good survival rates and few complications.

Ultrasound Assessment of Lung Aeration in Subjects Supported by Venovenous Extracorporeal Membrane Oxygenation.

BACKGROUND: The value of ultrasound in assessing lung aeration of patients with ARDS who require venovenous extracorporeal membrane oxygenation (ECMO) has, to our knowledge, never been studied. The objective of the study was to evaluate by using ultrasound lung aeration at ECMO initiation and withdrawal in subjects with severe ARDS supported by venovenous ECMO. METHODS: Fifty subjects were included in this pilot retrospective study. The lung ultrasound aeration score (LUS) and respiratory variables were collected at ECMO initiation (T0) and ECMO withdrawal (T1). The LUS at T0 between the subjects who survived to ICU discharge and those who died in ICU was compared. The relationship between changes in LUS and changes in PaO2 /FIO2 from T0 to T1 was assessed. RESULTS: The ICU mortality was 34%. The LUS at T0 did not differ between survivors and non-survivors (median 22 [interquartile range] {IQR} 19-26 vs median 24 [IQR, 19-28]; P = .60). From T0 to T1, the LUS decreased significantly in survivors (median 22 [IQR, 19-26] vs median 16 [IQR, 13-19]; P < .001), it decreased moderately in non-survivors who were weaned off ECMO (median 26 [24-29]) vs median 22 (IQR, 17-24), P = .031), and remained stable in those who died during ECMO (median 25 [IQR, 19-29] vs median 25 [IQR, 23-31]; P = .22). Changes in PaO2 /FIO2 were not related to changes in the LUS between T0 and T1. CONCLUSIONS: At the time of ECMO placement, the subjects who survived ARDS had aeration loss close to that observed in the subjects who did not survive. At the time of ECMO withdrawal, there was a significant improvement in lung aeration in the survivors, whereas a severe loss of lung aeration persisted in the non-survivors, although some were weaned off ECMO. Lung ultrasound provided a valuable tool for bedside assessment of lung aeration in subjects supported by ECMO.

Short-Term Effects of an Active Heat-and-Moisture Exchanger During Invasive Ventilation.

BACKGROUND: Humidification is a standard of care during invasive mechanical ventilation. Two types of devices are used for this purpose: heated humidifiers and heat-and-moisture exchangers (HME). AIM: To compare the short-term physiologic effects of an active HME, with those of heated humidifiers and HMEs in terms of respiratory effort, ventilatory pattern, and arterial blood gases during invasive mechanical ventilation. METHODS: We conducted a randomized crossover study with 3 different devices in 15 stable subjects who had a tracheostomy and were ventilator-dependent. Transdiaphragmatic pressure, ventilatory pattern, arterial blood gases, and dyspnea scale were recorded at baseline and at the end of a 20-min period with each device. RESULTS: Compared with heated humidifiers, the active HME was associated with higher diaphragmatic pressure-time product per minute (117.10 [interquartile range {IQR} 34.58-298.60]) versus 80.86 (IQR, 25.46-110.55) cm H2O×s/min, P = .01), higher PaCO2 (48.50 [IQR, 40.65-53.70] vs 39.60 [IQR, 37.50-49.95]) mm Hg, P = .02) and lower pH (7.41 [IQR, 7.36-7.49] vs 7.45 [IQR, 7.40-7.51], P = .030) without any significant difference in ventilatory pattern. A significantly worse dyspnea scale score (active HME, 3 (2-4) vs heated humidifiers: 4 (3-5); P = .009) was also observed. No significant differences were seen between active HME and HME. CONCLUSIONS: This study indicated that, compared with the heated humidifiers, the use of the active HME or the HME increased inspiratory effort, PaCO2 , pH, and dyspnea in stable subjects who were tracheostomized and ventilator-dependent. (ClinicalTrials.gov registration NCT02499796.).

European Respiratory Society International Congress 2018: highlights from Assembly 2 on respiratory intensive care.

The respiratory intensive care Assembly of the European Respiratory Society is proud to present a summary of several important sessions held at the International Congress in Paris in 2018. For the highly esteemed reader who may have missed the Congress, a concise review was written on three topics: the state-of-the-art session on respiratory critical care, hot topics in weaning and the best abstracts in noninvasive ventilation.

Physiotherapy and Weaning From Prolonged Mechanical Ventilation.

BACKGROUND: Patients undergoing prolonged mechanical ventilation represent up to 15% of all patients requiring weaning from mechanical ventilation. Although recent guidelines have recommended including physiotherapy early during mechanical ventilation to speed the process of weaning, only indirect evidence supporting the use of physiotherapy is available for patients receiving prolonged mechanical ventilation. The aim of our study was to evaluate the effects of a physiotherapy program in subjects requiring prolonged mechanical ventilation and the correlates of successful weaning. METHODS: A retrospective analysis was performed on 1,313 consecutive patients admitted to a weaning unit over a 15-y period to be liberated from prolonged mechanical ventilation. Subjects underwent a program of intensive physiotherapy organized in 4 incremental steps (1-4) and were analyzed according to the steps achieved (> 2 steps or ≤ 2 steps). The rate of successful weaning was recorded, and possible predictors were considered. The 15-y period of observation was divided into 3 consecutive 5-y intervals. RESULTS: Out of 560 subjects undergoing final analysis, 349 (62.3%) were successfully weaned. The weaning success rate was significantly greater in subjects attaining > 2 steps than in subjects who attained ≤ 2 steps (72.1% vs 55.9%, respectively, odds ratio = 2.04, 95% CI = 1.42-2.96, P < .001). Stepwise logistic regression analysis showed that achievement of > 2 physiotherapy steps was the main predictor of successful weaning (odds ratio = 2.17, 95% CI = 1.48-3.23, P < .001). Underlying disease was also a predictor of successful weaning. The overall rate of successful weaning decreased, and the median duration of weaning increased, during the period of observation. CONCLUSIONS: Our data support the inclusion of physiotherapy in the management of patients requiring prolonged mechanical ventilation.

Prevalence and Predictors of Obstructive Sleep Apnea in Patients with Chronic Obstructive Pulmonary Disease Undergoing Inpatient Pulmonary Rehabilitation.

The aim of our study was to evaluate the prevalence and predictors of obstructive sleep apnea (OSA) in patients with chronic obstructive pulmonary disease (COPD) undergoing inpatient pulmonary rehabilitation programs (PRPs). A retrospective data review of consecutive stable patients with a known diagnosis of COPD, admitted for PRP between January 2007 and December 2013. Full overnight polysomnography (PSG) and Epworth Sleepiness Scale (ESS) were assessed in all patients. Out of 422 evaluated patients, 190 (45%) showed an Apnea Hypopnea Index (AHI) ≥ 15 events/hour and underwent OSA treatment. Patients with OSA were significantly younger and had a less severe airway obstruction as compared to patients without OSA. There were no significant differences in cardiac comorbidities nor in arterial blood gases. As expected, patients with OSA showed significantly more severe diurnal symptoms, as assessed by the ESS and higher body mass index (BMI). However, only 69 out of 190 patients with OSA (36.3%) showed an ESS >10, whereas 25% of them had BMI ≤25 and 41% of them had a BMI <30. In all, 68% of patients with OSA were discharged with continuous positive airway pressure (CPAP), 15% with Bilevel ventilation, and 17% without any ventilatory treatment. In conclusion, in the population studied, the combination of OSA and COPD was frequent. BMI and ESS values commonly considered cutoff values for the prediction of OSA in the general population may not be accurate in a subgroup of patients with COPD.

Noninvasive ventilation in hypercapnic respiratory failure: from rocking beds to fancy masks.

A chronological account of some of the significant research into the application of NIV in acute hypercapnic respiratory failure over recent decades http://ow.ly/L5bZ30ktEG6.

Avoiding Respiratory and Peripheral Muscle Injury During Mechanical Ventilation: Diaphragm-Protective Ventilation and Early Mobilization.

Both limb muscle weakness and respiratory muscle weakness are exceedingly common in critically ill patients. Respiratory muscle weakness prolongs ventilator dependence, predisposing to nosocomial complications and death. Limb muscle weakness persists for months after discharge from intensive care and results in poor long-term functional status and quality of life. Major mechanisms of muscle injury include critical illness polymyoneuropathy, sepsis, pharmacologic exposures, metabolic derangements, and excessive muscle loading and unloading. The diaphragm may become weak because of excessive unloading (leading to atrophy) or because of excessive loading (either concentric or eccentric) owing to insufficient ventilator assistance.

Non-Invasive Mechanical Ventilation in Critically Ill Trauma Patients: A Systematic Review.

There is limited literature on non-invasive mechanical ventilation (NIMV) in patients with polytrauma-related acute respiratory failure (ARF). Despite an increasing worldwide application, there is still scarce evidence of significant NIMV benefits in this specific setting, and no clear recommendations are provided. We performed a systematic review, and a search of clinical databases including MEDLINE and EMBASE was conducted from the beginning of 1990 until today. Although the benefits in reducing the intubation rate, morbidity and mortality are unclear, NIMV may be useful and does not appear to be associated with harm when applied in properly selected patients with moderate ARF at an earlier stage of injury by experienced teams and in appropriate settings under strict monitoring. In the presence of these criteria, NIMV is worth attempting, but only if endotracheal intubation is promptly available because non-responders to NIMV are burdened by an increased mortality when intubation is delayed.

The effect of continuous positive airway pressure on pulmonary function may depend on the basal level of forced expiratory volume in 1 second.

BACKGROUND: The coexistence of chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA), also referred to as overlap syndrome (OS), is associated with a high rate of morbidity, COPD exacerbations and mortality. Treatment with continuous positive airway pressure (CPAP) has proven to significantly decrease the rate of these complications. However, data concerning the effect of CPAP on pulmonary function are scarce and conflicting. The aim of our study was to evaluate the effect of 1 year of CPAP treatment on arterial blood gases (ABGs) and pulmonary function tests in patients with OS and its potential relationship with the baseline severity of airway obstruction. A secondary aim was to search for predictors of changes in the evaluated parameters. METHODS: A retrospective study on a cohort of 92 patients (74 males) discharged from the Pulmonary Rehabilitation Unit of the Istituti Clinici Scientifici Maugeri in Pavia (Italy) from January 2013 to January 2016, with a diagnosis of OS and a prescription of CPAP, was conducted. Collected data at discharge were compared with 1-year follow-up data. RESULTS: After 1 year of CPAP, we observed the following: (I) a significant improvement in ABGs in all patients [median pO2 65.0 (59.0-70.0) vs. 71 (64.8-77.1) mmHg, pCO2 39.8 (36.2-43.5) vs. 38.3 (32.3-44.2) at baseline and after 1 year respectively, P<0.001], which was more pronounced in patients who were hypercapnic at baseline; (II) no significant change in respiratory function in the whole population; (III) a significant change in forced expiratory volume in 1 second (FEV1) only under and above a threshold of 79.1% of basal FEV1 with an opposite trend. In particular, patients with a basal FEV1 below that threshold significantly improved [median FEV1 70 (-70 to 200) mL, P=0.001], whereas patients with a basal FEV1 above the same threshold significantly worsened [median FEV1 -270 (-370 to -130) mL, P=3.05×10-5]. CONCLUSIONS: A population of overlap patients treated with CPAP may experience a different change in airflow obstruction after 1 year depending on the severity of baseline obstruction.