Appropriate Use of High-Flow Nasal Oxygen in Hospitalized Patients for Initial or Postextubation Management of Acute Respiratory Failure: A Clinical Guideline From the American College of Physicians.

DESCRIPTION: The American College of Physicians (ACP) developed this guideline to provide clinical recommendations on the appropriate use of high-flow nasal oxygen (HFNO) in hospitalized patients for initial or postextubation management of acute respiratory failure. It is based on the best available evidence on the benefits and harms of HFNO, taken in the context of costs and patient values and preferences. METHODS: The ACP Clinical Guidelines Committee based these recommendations on a systematic review on the efficacy and safety of HFNO. The patient-centered health outcomes evaluated included all-cause mortality, hospital length of stay, 30-day hospital readmissions, hospital-acquired pneumonia, days of intubation or reintubation, intensive care unit (ICU) admission and ICU transfers, patient comfort, dyspnea, delirium, barotrauma, compromised nutrition, gastric dysfunction, functional independence at discharge, discharge disposition, and skin breakdown. This guideline was developed using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) method. TARGET AUDIENCE AND PATIENT POPULATION: The target audience is all clinicians, and the target patient population is adult patients with acute respiratory failure treated in a hospital setting (including emergency departments, hospital wards, intermediate or step-down units, and ICUs). RECOMMENDATION 1A: ACP suggests that clinicians use high-flow nasal oxygen rather than noninvasive ventilation in hospitalized adults for the management of acute hypoxemic respiratory failure (conditional recommendation; low-certainty evidence). RECOMMENDATION 1B: ACP suggests that clinicians use high-flow nasal oxygen rather than conventional oxygen therapy for hospitalized adults with postextubation acute hypoxemic respiratory failure (conditional recommendation; low-certainty evidence).

Acute severe asthma: management and treatment.

Patients with acute asthma attack usually access the emergency room with severe functional impairment, despite low perception of symptoms. In this scenario, early functional assessment is essential focusing on vital parameters and respiratory function, alongside perceived dyspnea. Impairment of ventilatory mechanics due to progressive dynamic pulmonary hyperinflation should be promptly treated with medical inhalation and/or intravenous therapy, reserving intensive treatment in case of non-response and/or worsening of the clinical conditions. Therapeutic planning at patient's discharge is no less important than treatment management during emergency room access as educating the patient about therapeutic adherence significantly impact long-term outcomes of asthma. With this review we aimed at exploring current evidence on acute asthma attack management, focusing of pharmacological and ventilatory strategies of care and highlighting the importance of patient education once clinical stability allows discharge from the emergency department.

Ventilation-perfusion heterogeneity measured by the multiple inert gas elimination technique is minimally affected by intermittent breathing of 100% O2.

Proton magnetic resonance (MR) imaging to quantify regional ventilation-perfusion ( V˙A/Q˙ ) ratios combines specific ventilation imaging (SVI) and separate proton density and perfusion measures into a composite map. Specific ventilation imaging exploits the paramagnetic properties of O2 , which alters the local MR signal intensity, in an FI O2 -dependent manner. Specific ventilation imaging data are acquired during five wash-in/wash-out cycles of breathing 21% O2 alternating with 100% O2 over ~20 min. This technique assumes that alternating FI O2 does not affect V˙A/Q˙ heterogeneity, but this is unproven. We tested the hypothesis that alternating FI O2 exposure increases V˙A/Q˙ mismatch in nine patients with abnormal pulmonary gas exchange and increased V˙A/Q˙ mismatch using the multiple inert gas elimination technique (MIGET).The following data were acquired (a) breathing air (baseline), (b) breathing alternating air/100% O2 during an emulated-SVI protocol (eSVI), and (c) 20 min after ambient air breathing (recovery). MIGET heterogeneity indices of shunt, deadspace, ventilation versus V˙A/Q˙ ratio, LogSD V˙ , and perfusion versus V˙A/Q˙ ratio, LogSD Q˙ were calculated. LogSD V˙ was not different between eSVI and baseline (1.04 ± 0.39 baseline, 1.05 ± 0.38 eSVI, p = .84); but was reduced compared to baseline during recovery (0.97 ± 0.39, p = .04). There was no significant difference in LogSD Q˙ across conditions (0.81 ± 0.30 baseline, 0.79 ± 0.15 eSVI, 0.79 ± 0.20 recovery; p = .54); Deadspace was not significantly different (p = .54) but shunt showed a borderline increase during eSVI (1.0% ± 1.0 baseline, 2.6% ± 2.9 eSVI; p = .052) likely from altered hypoxic pulmonary vasoconstriction and/or absorption atelectasis. Intermittent breathing of 100% O2 does not substantially alter V˙A/Q˙ matching and if SVI measurements are made after perfusion measurements, any potential effects will be minimized.

Setting up home noninvasive ventilation.

Home noninvasive ventilation (NIV) is widely used to correct nocturnal alveolar hypoventilation in patients with chronic respiratory failure of various etiologies. The most commonly used ventilation mode is pressure support with a backup respiratory rate. This mode requires six main settings, as well as some additional settings that should be adjusted according to the individual patient. This review details the effect of each setting, how the settings should be adjusted according to each patient, and the risks if they are not adjusted correctly. The examples described here are based on real patient cases and bench simulations. Optimizing the settings for home NIV may improve the quality and tolerance of the treatment.

Spiroergometric measurements under increased inspiratory oxygen concentration (FIO2)-Putting the Haldane transformation to the test.

Spiroergometric measurements of persons who require oxygen insufflation due to illness can be performed under conditions of increased inspiratory oxygen concentration (FIO2). This increase in FIO2, however, often leads to errors in the calculation of oxygen consumption ([Formula: see text]). These inconsistencies are due to the application of the Haldane Transformation (HT), an otherwise indispensable correction factor in the calculation of [Formula: see text] that becomes inaccurate at higher FIO2 concentrations. A possible solution to this problem could be the use of the 'Eschenbacher transformation' (ET) as an alternative correction factor. This study examines the concentration of FIO2 at which the HT and the ET are valid, providing plausible data of oxygen consumption corresponding to the wattage achieved during cycle ergometry. Ten healthy volunteers underwent spiroergometric testing under standard conditions (FIO2 = 20.9%), as well as at FIO2 = 40% and 80%. When compared with the predicted values of [Formula: see text], as calculated according to Wasserman et al. (2012), the data obtained show that both the HT and ET are valid under normal conditions and at an increased FIO2 of 40%. At FIO2 concentrations of 80%, however, the [Formula: see text] values provided by the HT begin to lose plausibility, whereas the ET continues to provide credible results. We conclude that the use of the ET in place of the HT in spiroergometric measurements with increased FIO2 allows a reliable evaluation of stress tests in patients requiring high doses of supplemental oxygen.

Tolerance to a haemorrhagic challenge during heat stress is improved with inspiratory resistance breathing.

NEW FINDINGS: What is the central question of this study? Does inspiratory resistance breathing improve tolerance to simulated haemorrhage in individuals with elevated internal temperatures? What is the main finding and its importance? The main finding of this study is that inspiratory resistance breathing modestly improves tolerance to a simulated progressive haemorrhagic challenge during heat stress. These findings demonstrate a scenario in which exploitation of the respiratory pump can ameliorate serious conditions related to systemic hypotension. ABSTRACT: Heat exposure impairs human blood pressure control and markedly reduces tolerance to a simulated haemorrhagic challenge. Inspiratory resistance breathing enhances blood pressure control and improves tolerance during simulated haemorrhage in normothermic individuals. However, it is unknown whether similar improvements occur with this manoeuvre in heat stress conditions. In this study, we tested the hypothesis that inspiratory resistance breathing improves tolerance to simulated haemorrhage in individuals with elevated internal temperatures. On two separate days, eight subjects performed a simulated haemorrhage challenge [lower-body negative pressure (LBNP)] to presyncope after an increase in internal temperature of 1.3 ± 0.1°C. During one trial, subjects breathed through an inspiratory impedance device set at 0 cmH2 O of resistance (Sham), whereas on a subsequent day the device was set at -7 cmH2 O of resistance (ITD). Tolerance was quantified as the cumulative stress index. Subjects were more tolerant to the LBNP challenge during the ITD protocol, as indicated by a > 30% larger cumulative stress index (Sham, 520 ± 306 mmHg min; ITD, 682 ± 324 mmHg min; P < 0.01). These data indicate that inspiratory resistance breathing modestly improves tolerance to a simulated progressive haemorrhagic challenge during heat stress.

Anesthetic challenges of a patient with the communicating bulla coming for nonthoracic surgery.

Management of a patient with a giant bulla coming for a nonthoracic surgery is rare, and its anesthetic management is very challenging. It is imperative to isolate only the subsegmental bronchus, in which the bulla communicates to avoid respiratory morbidities such as pneumothorax, emphysema or atelectasis of the surrounding lung parenchyma, and postoperative respiratory failure. Herewith, we want to report the anesthetic challenges of a patient with giant bulla communicating into one of the subsegmental right upper lobe bronchus for splenectomy.

Pulse Pressure Variation and Weight-Loss Percentage Predict Hypotension After Anesthesia Induction in Neurosurgery Patients: A Prospective, Observational, Blinded Study.

BACKGROUND: Hypotension after anesthesia induction is a common problem and is partly related to patient volume status. The present study aimed to investigate the correlation between blood pressure change and pulse pressure variation (PPV), and percentage of weight loss while determining threshold for hypotension by receiver operating characteristic analysis. METHODS: We analyzed 231 neurosurgery patients. In all patients, propofol was used for standard anesthesia induction. Patient demographics, medical histories, fasting duration, percentage weight loss, baseline blood pressure, and PPV during normal tidal volume breathing and that during forced inspiratory breathing (PPVfi) were recorded. Hemodynamic changes within 10 minutes of intubation were observed. Patients developing hypotension and severe hypotension were determined; lowest mean arterial pressure (MAP) and systolic arterial pressure (SAP) values were recorded, and their differences relative to baseline values were calculated. RESULTS: The incidence of hypotension was 18.6%. Both percentage weight loss and PPVfi were correlated with the changes in MAP and SAP. A PPVfi>14 identified all observed hypotensive episodes with 86% sensitivity and 86.2% specificity, whereas percentage weight loss >1.75% identified all observed hypotensive episodes with 81.4% sensitivity and 70.7% specificity. Furthermore, PPVfi>16.5 identified severe hypotension with 85% sensitivity and 90.5% specificity, whereas percentage weight loss >1.95% identified severe hypotension with 85% sensitivity and 73% specificity. CONCLUSIONS: Percentage weight loss and PPVfi are good predictors of hypotension after anesthesia induction and, thus, may allow anesthesiologists to adopt preventative measures and ensure safer anesthesia induction.

Association of Noninvasive Ventilation Strategies With Mortality and Bronchopulmonary Dysplasia Among Preterm Infants: A Systematic Review and Meta-analysis.

IMPORTANCE: Various noninvasive ventilation strategies are used to prevent bronchopulmonary dysplasia (BPD) of preterm infants; however, the best mode is uncertain. OBJECTIVE: To compare 7 ventilation strategies for preterm infants including nasal continuous positive airway pressure (CPAP) alone, intubation and surfactant administration followed by immediate extubation (INSURE), less invasive surfactant administration (LISA), noninvasive intermittent positive pressure ventilation, nebulized surfactant administration, surfactant administration via laryngeal mask airway, and mechanical ventilation. DATA SOURCES: MEDLINE, EMBASE, CINAHL, and Cochrane CENTRAL from their inceptions to June 2016. STUDY SELECTION: Randomized clinical trials comparing ventilation strategies for infants younger than 33 weeks' gestational age within 24 hours of birth who had not been intubated. DATA EXTRACTION AND SYNTHESIS: Data were independently extracted by 2 reviewers and synthesized with Bayesian random-effects network meta-analyses. MAIN OUTCOMES AND MEASURES: A composite of death or BPD at 36 weeks' postmenstrual age was the primary outcome. Death, BPD, severe intraventricular hemorrhage, and air leak by discharge were the main secondary outcomes. RESULTS: Among 5598 infants involved in 30 trials, the incidence of the primary outcome was 33% (1665 of 4987; including 505 deaths and 1160 cases of BPD). The secondary outcomes ranged from 6% (314 of 5587) for air leak to 26% (1160 of 4455) for BPD . Compared with mechanical ventilation, LISA had a lower odds of the primary outcome (odds ratio [OR], 0.49; 95% credible interval [CrI], 0.30-0.79; absolute risk difference [RD], 164 fewer per 1000 infants; 57-253 fewer per 1000 infants; moderate quality of evidence), BPD(OR, 0.53; 95% CrI, 0.27-0.96; absolute RD, 133 fewer per 1000 infants; 95% CrI, 9-234 fewer per 1000 infants; moderate-quality), and severe intraventricular hemorrhage (OR, 0.44; 95% CrI, 0.19-0.99; absolute RD, 58 fewer per 1000 births; 95% CrI, 1-86 fewer per 1000 births; moderate-quality). Compared with nasal CPAP alone, LISA had a lower odds of the primary outcome (OR, 0.58; 95% CrI, 0.35-0.93; absolute RD, 112 fewer per 1000 births; 95% CrI, 16-190 fewer per 1000 births; moderate quality), and air leak (OR, 0.24; 95% CrI, 0.05-0.96; absolute RD, 47 fewer per 1000 births; 95% CrI, 2-59 fewer per 1000 births; very low quality). Ranking probabilities indicated that LISA was the best strategy with a surface under the cumulative ranking curve of 0.85 to 0.94, but this finding was not robust for death when limited to higher-quality evidence. CONCLUSIONS AND RELEVANCE: Among preterm infants, the use of LISA was associated with the lowest likelihood of the composite outcome of death or BPD at 36 weeks' postmenstrual age. These findings were limited by the overall low quality of evidence and lack of robustness in higher-quality trials.

Effects of Lung Expansion Therapy on Lung Function in Patients with Prolonged Mechanical Ventilation.

Common complications in PMV include changes in the airway clearance mechanism, pulmonary function, and respiratory muscle strength, as well as chest radiological changes such as atelectasis. Lung expansion therapy which includes IPPB and PEEP prevents and treats pulmonary atelectasis and improves lung compliance. Our study presented that patients with PMV have improvements in lung volume and oxygenation after receiving IPPB therapy. The combination of IPPB and PEEP therapy also results in increase in respiratory muscle strength. The application of IPPB facilitates the homogeneous gas distribution in the lung and results in recruitment of collapsed alveoli. PEEP therapy may reduce risk of respiratory muscle fatigue by preventing premature airway collapse during expiration. The physiologic effects of IPPB and PEEP may result in enhancement of pulmonary function and thus increase the possibility of successful weaning from mechanical ventilator during weaning process. For patients with PMV who were under the risk of atelectasis, the application of IPPB may be considered as a supplement therapy for the enhancement of weaning outcome during their stay in the hospital.

An appropriate inspiratory flow pattern can enhance CO2 exchange, facilitating protective ventilation of healthy lungs.

BACKGROUND: In acute lung injury, CO2 exchange is enhanced by prolonging the volume-weighted mean time for fresh gas to mix with resident alveolar gas, denoted mean distribution time (MDT), and by increasing the flow rate immediately before inspiratory flow interruption, end-inspiratory flow (EIF). The objective was to study these effects in human subjects without lung disease and to analyse the results with respect to lung-protective ventilation of healthy lungs. METHODS: During preparation for intracranial surgery, the lungs of eight subjects were ventilated with a computer-controlled ventilator, allowing breath-by-breath modification of the inspiratory flow pattern. The durations of inspiration (TI) and postinspiratory pause (TP) were modified, as was the profile of the inspiratory flow wave (i.e. constant, increasing, or decreasing). The single-breath test for CO2 was used to quantify airway dead space (VDaw) and CO2 exchange. RESULTS: A long MDT and a high EIF augment CO2 elimination by reducing VDaw and promoting mixing of tidal gas with resident alveolar gas. A heat and moisture exchanger had no other effect than enlarging VDaw. A change of TI from 33 to 15% and of TP from 10 to 28%, leaving the time for expiration unchanged, would augment tidal elimination of CO2 by 14%, allowing a 10% lower tidal volume. CONCLUSIONS: In anaesthetized human subjects without lung disease, CO2 exchange is enhanced by a long MDT and a high EIF. A short TI and a long TP allow significant reduction of tidal volume when lung-protective ventilation is required. CLINICAL TRIAL REGISTRATION: NCT01686984.

A Pilot Randomized Trial Comparing Weaning From Mechanical Ventilation on Pressure Support Versus Proportional Assist Ventilation.

OBJECTIVES: Despite protocols incorporating spontaneous breathing trials, 31% of ICU patients experience difficult or prolonged weaning from mechanical ventilation. Nonfatiguing modes such as pressure support ventilation are recommended. Proportional assist ventilation provides assistance in proportion to patient effort, which may optimize weaning. However, it is not known how proportional assist ventilation performs relative to pressure support ventilation over a prolonged period in the complex ICU setting. The purpose of this study was to compare the physiologic and clinical performance (failure rate), safety, and feasibility of protocols using daily spontaneous breathing trial plus pressure support ventilation versus proportional assist ventilation until ventilation discontinuation. DESIGN: Single-center, unblinded pilot randomized controlled trial. SETTING: Medical-surgical ICU of a tertiary-care hospital. PATIENTS: Adult patients intubated greater than 36 hours were randomized if they met eligibility criteria for partial ventilatory support, tolerated pressure support ventilation greater than or equal to 30 minutes, and either failed or did not meet criteria for a spontaneous breathing trial. INTERVENTIONS: Patients were randomized to the pressure support ventilation or proportional assist ventilation protocol (PAV+, Puritan Bennett 840; Covidien, Boulder, CO). Both protocols used progressive decreases in level of assistance as tolerated, coupled with daily assessment for spontaneous breathing trials. MEASUREMENTS AND MAIN RESULTS: Of 54 patients randomized, outcome data are available for 50 patients; 27 were randomized to receive proportional assist ventilation and 23 to receive pressure support ventilation. There were no adverse events linked to the study interventions, and protocol violations were infrequent. Recruitment was slower than projected (1.3 patients per month). The median (interquartile range) time from randomization to successful extubation was 3.9 days (2.8-8.4 d) on proportional assist ventilation versus 4.9 days (2.9-26.3 d) on pressure support ventilation (p = 0.39). Time to live ICU discharge was 7.3 days (5.2-11.4 d) on proportional assist ventilation versus 12.4 days (7.5-30.8 d) on pressure support ventilation (p = 0.03). CONCLUSION: This pilot study demonstrates the utility, safety, and feasibility of the weaning protocols and provides important information to guide the design of a future randomized controlled trial comparing weaning from mechanical ventilation on pressure support ventilation versus proportional assist ventilation.

Efeitos da RPPI sobre os volumes pulmonares em pacientes submetidos à cirurgia cardíaca / Effects of RPPI on pulmonary volumes in patients undergoing cardiac surgery

As doenças cardiovasculares ocupam, atualmente, o primeiro lugar dentre as principais causas de morte no mundo. No Brasil, representam um terço de todos os óbitos e quase 30% do total de mortes na faixa etária de 20 a 59 anos de idade. A realização de cirurgia cardíaca contribui para a diminuição dos sintomas associados à essas doenças, além de promover melhora na qualidade de vida e aumento da sobrevida dos indivíduos cardiopatas...

Ultrasound assessment of congenital fetal lung masses and neonatal respiratory outcomes.

OBJECTIVE: Fetal congenital lung masses generate concern for compromised postnatal respiratory function. Congenital pulmonary adenomatoid malformation volume ratio (CVR) has been used to predict the risk of hydrops fetalis and need for antenatal intervention. This study investigates whether CVR could be used to predict neonatal respiratory outcomes. METHODS: The ultrasounds of fetuses diagnosed with a lung mass between 2005 and 2013 were reviewed. CVR was calculated at each ultrasound using the formula for a prolate ellipse divided by head circumference. The pregnancy outcome and information about NICU admission for respiratory insufficiency were collected. RESULTS: Forty-two fetuses were diagnosed with a lung mass during the study period. CVR prior to 24 weeks and between 24 and 32 weeks were associated with NICU admission (p < 0.0001 and <0.008, respectively). CVR increased up to 32 weeks and decreased thereafter for most subjects. The decrease in CVR beyond 32 weeks was larger for cases that required NICU admission (p = 0.002). For a CVR cut-off of <0.5, the sensitivity was 100%, the specificity 85.7%, and negative predictive value was 100% for regular nursery care. CONCLUSION: In pregnancies diagnosed with fetal lung masses, CVR predicted normal respiratory outcomes and need for NICU admission. This information may be helpful for delivery planning. © 2015 John Wiley & Sons, Ltd.

Optimum insufflation capacity and peak cough flow in neuromuscular disorders.

RATIONALE: For patients with neuromuscular disorders, lung insufflation with positive pressure is an accepted technique to increase inspiratory volume over VC to improve peak cough flow (PCF). OBJECTIVES: The aim of the study was to determine the pressure or volume required to achieve the highest individual PCF. METHODS: In 40 patients dependent on noninvasive ventilation (VC, 16 ± 11% predicted; age, 20 ± 4 yr) and in 20 healthy control subjects, insufflation capacity (IC) was measured during titration from 10 to maximum 40 mbar using intermittent positive pressure breathing (IPPB) or the lung insufflation assist maneuver (LIAM) of the VENTIlogic LS ventilator. MEASUREMENTS AND MAIN RESULTS: IPPB or LIAM titration resulted in a pressure-volume curve with an estimated total compliance of 0.23 ± 0.11 L/kPa in the patients and 1.0 ± 0.3 L/kPa in the controls and a plateau for IC at pressures between 30 and 40 mbar. IPPB or LIAM improved VC from 451 ± 229 ml to a maximum IC (ICmax) of 1,027 ± 329 ml, and PCF improved from 109 ± 45 to 202 ± 62 L/min (P < 0.01 for all). The highest individual PCF was achieved with 27 ± 6 mbar and an IC of 924 ± 379 ml, which was significantly below ICmax (P < 0.01). CONCLUSIONS: A submaximal insufflation is ideal for generating the best individual PCF even in patients with severely reduced compliance of the respiratory system. Optimum insufflation capacity can be achieved using IPPB or LIAM with moderate pressures. Both techniques are equally effective and considered safe.

Comparison of three cough-augmentation techniques in neuromuscular patients: mechanical insufflation combined with manually assisted cough, insufflation-exsufflation alone and insufflation-exsufflation combined with manually assisted cough.

BACKGROUND: Mechanical insufflation-exsufflation (MI-E), more commonly known as 'cough assist therapy', is a method which produces inspiratory and expiratory assistance to improve cough performances. However, other alternatives or combinations are possible. OBJECTIVE: The objective was to compare the effects of mechanical insufflation combined with manually assisted coughing (MAC), insufflation-exsufflation alone and insufflation-exsufflation combined with MAC in neuromuscular patients requiring cough assistance. METHODS: Eighteen neuromuscular patients with severe respiratory muscle dysfunction and peak cough flow (PCF) lower than 3 liters/s or maximal expiratory pressure (MEP) lower than +45 cm H2O were studied. Patients were studied under three cough-assisted conditions, which were used in random order: insufflation by intermittent positive-pressure breathing (IPPB) combined with MAC, MI-E and MI-E + MAC. RESULTS: Overall, PCF was higher with IPPB + MAC than with MI-E + MAC or MI-E alone. Among the 12 patients who had higher PCF values with IPPB + MAC than with the two other techniques, 9 exhibited mask pressure swings during MI-E exsufflation, with a transient positive-pressure value due to the expiratory flow produced by the combined patient cough effort and MAC. Each of these 9 patients had higher PCF values (>5 liters/s) than did the other 9 patients when using IPPB + MAC. CONCLUSION: Our results indicate that adding the MI-E device to MAC is unhelpful in patients whose PCF with an insufflation technique and MAC exceeds 5 liters/s. This is because the expiratory flow produced by the patient's effort and MAC transitorily exceeds the vacuum capacity of the MI-E device, which therefore becomes a transient load against the PCF.

Fiber-optic bronchoscopy and volume-cycled mouthpiece ventilation for a patient with multiple sclerosis and ventilatory failure.

Fiber-optic bronchoscopy supported by continuous or bilevel positive airway pressure has helped patients with hypoxemic or hypercapnic respiratory failure avoid respiratory complications. The authors describe a case of a 57-yr-old man with multiple sclerosis with a vital capacity of 250 ml (5% of predicted normal) who was using continuous noninvasive intermittent positive pressure ventilatory support when he underwent bronchoscopy while receiving continuous noninvasive intermittent positive pressure ventilatory support via a 15-mm angled mouthpiece interface. He was switched from a nasal to a 15-mm angled mouthpiece interface for continuous noninvasive intermittent positive pressure ventilatory support for the procedure. Simple mouthpieces may be useful alternatives to other facial interfaces for ventilatory support during bronchoscopy because of patient comfort and operator convenience.

Evaluation of manual and automatic manually triggered ventilation performance and ergonomics using a simulation model.

BACKGROUND: In the absence of endotracheal intubation, the manual bag-valve-mask (BVM) is the most frequently used ventilation technique during resuscitation. The efficiency of other devices has been poorly studied. The bench-test study described here was designed to evaluate the effectiveness of an automatic, manually triggered system, and to compare it with manual BVM ventilation. METHODS: A respiratory system bench model was assembled using a lung simulator connected to a manikin to simulate a patient with unprotected airways. Fifty health-care providers from different professional groups (emergency physicians, residents, advanced paramedics, nurses, and paramedics; n = 10 per group) evaluated manual BVM ventilation, and compared it with an automatic manually triggered device (EasyCPR). Three pathological situations were simulated (restrictive, obstructive, normal). Standard ventilation parameters were recorded; the ergonomics of the system were assessed by the health-care professionals using a standard numerical scale once the recordings were completed. RESULTS: The tidal volume fell within the standard range (400-600 mL) for 25.6% of breaths (0.6-45 breaths) using manual BVM ventilation, and for 28.6% of breaths (0.3-80 breaths) using the automatic manually triggered device (EasyCPR) (P < .0002). Peak inspiratory airway pressure was lower using the automatic manually triggered device (EasyCPR) (10.6 ± 5 vs 15.9 ± 10 cm H2O, P < .001). The ventilation rate fell consistently within the guidelines, in the case of the automatic manually triggered device (EasyCPR) only (10.3 ± 2 vs 17.6 ± 6, P < .001). Significant pulmonary overdistention was observed when using the manual BVM device during the normal and obstructive sequences. The nurses and paramedics considered the ergonomics of the automatic manually triggered device (EasyCPR) to be better than those of the manual device. CONCLUSIONS: The use of an automatic manually triggered device may improve ventilation efficiency and decrease the risk of pulmonary overdistention, while decreasing the ventilation rate.