The use of head helmets to deliver noninvasive ventilatory support: a comprehensive review of technical aspects and clinical findings.
TL;DR: A helmet, comprising a transparent hood and a soft collar, surrounding the patient's head can be used to deliver non-invasive ventilatory support, both as continuous positive airway pressure and noninvasive positive pressure ventilation (NPPV), the latter providing active support for inspiration as discussed by the authors.
Abstract: A helmet, comprising a transparent hood and a soft collar, surrounding the patient's head can be used to deliver noninvasive ventilatory support, both as continuous positive airway pressure and noninvasive positive pressure ventilation (NPPV), the latter providing active support for inspiration. In this review, we summarize the technical aspects relevant to this device, particularly how to prevent CO2 rebreathing and improve patient-ventilator synchrony during NPPV. Clinical studies describe the application of helmets in cardiogenic pulmonary oedema, pneumonia, COVID-19, postextubation and immune suppression. A section is dedicated to paediatric use. In summary, helmet therapy can be used safely and effectively to provide NIV during hypoxemic respiratory failure, improving oxygenation and possibly leading to better patient-centred outcomes than other interfaces.
Citations
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TL;DR: Comfort is one of the major determinants of NIV success and all the strategies aimed to increase comfort during NIV should be pursued.
Abstract: Non-invasive ventilation (NIV) has been shown to be effective in avoiding intubation and improving survival in patients with acute hypoxemic respiratory failure (ARF) when compared to conventional oxygen therapy. However, NIV is associated with high failure rates due, in most cases, to patient discomfort. Therefore, increasing attention has been paid to all those interventions aimed at enhancing patient's tolerance to NIV. Several practical aspects have been considered to improve patient adaptation. In particular, the choice of the interface and the ventilatory setting adopted for NIV play a key role in the success of respiratory assistance. Among the different NIV interfaces, tolerance is poorest for the nasal and oronasal masks, while helmet appears to be better tolerated, resulting in longer use and lower NIV failure rates. The choice of fixing system also significantly affects patient comfort due to pain and possible pressure ulcers related to the device. The ventilatory setting adopted for NIV is associated with varying degrees of patient comfort: patients are more comfortable with pressure-support ventilation (PSV) than controlled ventilation. Furthermore, the use of electrical activity of the diaphragm (EADi)-driven ventilation has been demonstrated to improve patient comfort when compared to PSV, while reducing neural drive and effort. If non-pharmacological remedies fail, sedation can be employed to improve patient's tolerance to NIV. Sedation facilitates ventilation, reduces anxiety, promotes sleep, and modulates physiological responses to stress. Judicious use of sedation may be an option to increase the chances of success in some patients at risk for intubation because of NIV intolerance consequent to pain, discomfort, claustrophobia, or agitation. During the Coronavirus Disease-19 (COVID-19) pandemic, NIV has been extensively employed to face off the massive request for ventilatory assistance. Prone positioning in non-intubated awake COVID-19 patients may improve oxygenation, reduce work of breathing, and, possibly, prevent intubation. Despite these advantages, maintaining prone position can be particularly challenging because poor comfort has been described as the main cause of prone position discontinuation. In conclusion, comfort is one of the major determinants of NIV success. All the strategies aimed to increase comfort during NIV should be pursued.
15 citations
TL;DR: In this paper , two types of filters were used for this purpose: a heat and moisture exchanger filter and an electrostatic filter, and the results showed that the use of filters during helmet CPAP reduced the flow delivered to the helmet and, consequently, modified FIO2.
Abstract: BACKGROUND: When helmet CPAP is performed using a Venturi system, filters are frequently interposed in the respiratory circuit to reduce noise within the helmet. The effect of the interposition of these filters on delivered fresh gas flow and the resulting FIO2 is currently unknown. METHODS: In a bench study, 2 different Venturi systems (WhisperFlow and Harol) were used to generate 3 different gas flow/FIO2 combinations (80 L/min-FIO2 0.6, 100 L/min-FIO2 0.5, 120 L/min-FIO2 0.4). Different combinations of filters were applied at the flow generator input line and/or at the helmet inlet port. Two types of filters were used for this purpose: a heat and moisture exchanger filter and an electrostatic filter. The setup without filters was used as baseline. Gas flow and FIO2 were measured for each setup. RESULTS: Compared to baseline, the interposition of filters reduced the gas flow between 1–13% (P < .001). The application of a filter at the Venturi system or at the helmet generated a comparable flow reduction (−3 ± 2% vs −4 ± 2%, P = .12), whereas a greater flow reduction (−7 ± 4%) was observed when filters were applied at both sites (P < .001). An increase in FIO2 up to 5% was observed with filters applied. A strong inverse linear relationship (P < .001) was observed between the resulting gas flow and FIO2. CONCLUSIONS: The use of filters during helmet CPAP reduced the flow delivered to the helmet and, consequently, modified FIO2. If filters are applied, an adequate gas flow should be administered to guarantee a constant CPAP during the entire respiratory cycle and avoid rebreathing. Moreover, it might be important to measure the effective FIO2 delivered to the patient to guarantee a precise assessment of oxygenation.
10 citations
TL;DR: Patients who fail noninvasive support are burdened by worse clinical outcome due to delays in endotracheal intubation with progres-sion of lung injury caused by the prolonged exposure of injured lungs to high inspiratory effort combined to ventilatory heterogeneities.
7 citations
TL;DR: In this paper , the authors summarize the rationale, mechanism of action and technicalities for helmet support in hypoxemic patients, and conclude that helmet non-invasive support may provide advantages over other noninvasive oxygenation strategies.
Abstract: Abstract Introduction Helmet noninvasive support may provide advantages over other noninvasive oxygenation strategies in the management of acute hypoxemic respiratory failure. In this narrative review based on a systematic search of the literature, we summarize the rationale, mechanism of action and technicalities for helmet support in hypoxemic patients. Main results In hypoxemic patients, helmet can facilitate noninvasive application of continuous positive-airway pressure or pressure-support ventilation via a hood interface that seals at the neck and is secured by straps under the arms. Helmet use requires specific settings. Continuous positive-airway pressure is delivered through a high-flow generator or a Venturi system connected to the inspiratory port of the interface, and a positive end-expiratory pressure valve place at the expiratory port of the helmet; alternatively, pressure-support ventilation is delivered by connecting the helmet to a mechanical ventilator through a bi-tube circuit. The helmet interface allows continuous treatments with high positive end-expiratory pressure with good patient comfort. Preliminary data suggest that helmet noninvasive ventilation (NIV) may provide physiological benefits compared to other noninvasive oxygenation strategies (conventional oxygen, facemask NIV, high-flow nasal oxygen) in non-hypercapnic patients with moderate-to-severe hypoxemia (PaO 2 /FiO 2 ≤ 200 mmHg), possibly because higher positive end-expiratory pressure (10–15 cmH 2 O) can be applied for prolonged periods with good tolerability. This improves oxygenation, limits ventilator inhomogeneities, and may attenuate the potential harm of lung and diaphragm injury caused by vigorous inspiratory effort. The potential superiority of helmet support for reducing the risk of intubation has been hypothesized in small, pilot randomized trials and in a network metanalysis. Conclusions Helmet noninvasive support represents a promising tool for the initial management of patients with severe hypoxemic respiratory failure. Currently, the lack of confidence with this and technique and the absence of conclusive data regarding its efficacy render helmet use limited to specific settings, with expert and trained personnel. As per other noninvasive oxygenation strategies, careful clinical and physiological monitoring during the treatment is essential to early identify treatment failure and avoid delays in intubation.
4 citations
TL;DR: In this article , a check-list has been made of nine key interventions based on the available evidence regarding system set up, monitoring and management, which may help nurses and physicians to increase the comfort of patients treated with Helmet CPAP and enhance their compliance with long-term treatment.
4 citations
References
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TL;DR: Treatment with helmet NIV resulted in a significant reduction of intubation rates among patients with ARDS and a statistically significant reduction in 90-day mortality.
Abstract: Importance Noninvasive ventilation (NIV) with a face mask is relatively ineffective at preventing endotracheal intubation in patients with acute respiratory distress syndrome (ARDS). Delivery of NIV with a helmet may be a superior strategy for these patients. Objective To determine whether NIV delivered by helmet improves intubation rate among patients with ARDS. Design, Setting, and Participants Single-center randomized clinical trial of 83 patients with ARDS requiring NIV delivered by face mask for at least 8 hours while in the medical intensive care unit at the University of Chicago between October 3, 2012, through September 21, 2015. Interventions Patients were randomly assigned to continue face mask NIV or switch to a helmet for NIV support for a planned enrollment of 206 patients (103 patients per group). The helmet is a transparent hood that covers the entire head of the patient and has a rubber collar neck seal. Early trial termination resulted in 44 patients randomized to the helmet group and 39 to the face mask group. Main Outcomes and Measures The primary outcome was the proportion of patients who required endotracheal intubation. Secondary outcomes included 28-day invasive ventilator–free days (ie, days alive without mechanical ventilation), duration of ICU and hospital length of stay, and hospital and 90-day mortality. Results Eighty-three patients (45% women; median age, 59 years; median Acute Physiology and Chronic Health Evaluation [APACHE] II score, 26) were included in the analysis after the trial was stopped early based on predefined criteria for efficacy. The intubation rate was 61.5% (n = 24) for the face mask group and 18.2% (n = 8) for the helmet group (absolute difference, −43.3%; 95% CI, −62.4% to −24.3%; P P P = .02). Adverse events included 3 interface-related skin ulcers for each group (ie, 7.6% in the face mask group had nose ulcers and 6.8% in the helmet group had neck ulcers). Conclusions and Relevance Among patients with ARDS, treatment with helmet NIV resulted in a significant reduction of intubation rates. There was also a statistically significant reduction in 90-day mortality with helmet NIV. Multicenter studies are needed to replicate these findings. Trial Registration clinicaltrials.gov Identifier:NCT01680783
425 citations
TL;DR: NPPV, especially CPAP, in addition to standard medical care is an effective and safe intervention for the treatment of adult patients with acute cardiogenic pulmonary edema.
Abstract: Background
This is an update of a systematic review previously published in 2008 about non-invasive positive pressure ventilation (NPPV). NPPV has been widely used to alleviate signs and symptoms of respiratory distress due to cardiogenic pulmonary oedema. NPPV prevents alveolar collapse and helps redistribute intra-alveolar fluid, improving pulmonary compliance and reducing the pressure of breathing.
Objectives
To determine the effectiveness and safety of NPPV in the treatment of adult patients with cardiogenic pulmonary oedema in its acute stage.
Search methods
We searched the following databases on 20 April 2011: CENTRAL and DARE, (The Cochrane Library, Issue 2 of 4, 2011); MEDLINE (Ovid, 1950 to April 2011); EMBASE (Ovid, 1980 to April 2011); CINAHL (1982 to April 2011); and LILACS (1982 to April 2011). We also reviewed reference lists of included studies and contacted experts and equipment manufacturers. We did not apply language restrictions.
Selection criteria
We selected blinded or unblinded randomised or quasi-randomised clinical trials, reporting on adult patients with acute or acute-on-chronic cardiogenic pulmonary oedema and where NPPV (continuous positive airway pressure (CPAP) or bilevel NPPV) plus standard medical care was compared with standard medical care alone.
Data collection and analysis
Two authors independently selected articles and abstracted data using a standardised data collection form. We evaluated study quality with emphasis on allocation concealment, sequence generation allocation, losses to follow-up, outcome assessors, selective outcome reporting and adherence to the intention-to-treat principle.
Main results
We included 32 studies (2916 participants), of generally low or uncertain risk of bias. Compared with standard medical care, NPPV significantly reduced hospital mortality (RR 0.66, 95% CI 0.48 to 0.89) and endotracheal intubation (RR 0.52, 95% CI 0.36 to 0.75). We found no difference in hospital length of stay with NPPV; however, intensive care unit stay was reduced by 1 day (WMD -0.89 days, 95% CI -1.33 to -0.45). Compared with standard medical care, we did not observe significant increases in the incidence of acute myocardial infarction with NPPV during its application (RR 1.24, 95% CI 0.79 to 1.95) or after (RR 0.70, 95% CI 0.11 to 4.26). We identified fewer adverse events with NPPV use (in particular progressive respiratory distress and neurological failure (coma)) when compared with standard medical care.
Authors' conclusions
NPPV in addition to standard medical care is an effective and safe intervention for the treatment of adult patients with acute cardiogenic pulmonary oedema. The evidence to date on the potential benefit of NPPV in reducing mortality is entirely derived from small-trials and further large-scale trials are needed.
334 citations
TL;DR: The aim of this article is to provide evidence-based recommendations for the correct use of “respiratory devices” in the COVID-19 emergency and protect healthcare workers from contracting the SARS-CoV-2 infection.
Abstract: The World Health Organization has recently defined the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection a pandemic. The infection, that may cause a potentially very severe respiratory disease, now called coronavirus disease 2019 (COVID-19), has airborne transmission via droplets. The rate of transmission is quite high, higher than common influenza. Healthcare workers are at high risk of contracting the infection particularly when applying respiratory devices such as oxygen cannulas or noninvasive ventilation. The aim of this article is to provide evidence-based recommendations for the correct use of "respiratory devices" in the COVID-19 emergency and protect healthcare workers from contracting the SARS-CoV-2 infection.
330 citations
TL;DR: NPSV by helmet successfully treated hypoxemic ARF, with better tolerance and fewer complications than facial mask NPSV.
Abstract: Objective To assess the efficacy of noninvasive pressure support ventilation (NPSV) using a new special helmet as first-line intervention to treat patients with hypoxemic acute respiratory failure (ARF), in comparison to NPSV using standard facial mask. Design and setting Prospective clinical pilot investigation with matched control group in three intensive care units of university hospitals. Patients and methods Thirty-three consecutive patients without chronic obstructive pulmonary disease and with hypoxemic ARF (defined as severe dyspnea at rest, respiratory rate >30 breaths/min, PaO2:FiO2 Results The 33 patients and the 66 controls had similar characteristics at baseline. Both groups improved oxygenation after NPSV. Eight patients (24%) in the helmet group and 21 patients (32%) in the facial mask group (p = .3) failed NPSV and were intubated. No patients failed NPSV because of intolerance of the technique in the helmet group in comparison with 8 patients (38%) in the mask group (p = .047). Complications related to the technique (skin necrosis, gastric distension, and eye irritation) were fewer in the helmet group compared with the mask group (no patients vs. 14 patients (21%), p = .002). The helmet allowed the continuous application of NPSV for a longer period of time (p = .05). Length of stay in the intensive care unit, intensive care, and hospital mortality were not different. Conclusions NPSV by helmet successfully treated hypoxemic ARF, with better tolerance and fewer complications than facial mask NPSV.
269 citations
TL;DR: Treatment with noninvasive oxygenation strategies compared with standard oxygen therapy was associated with lower risk of death, and network meta-analyses using a bayesian framework to derive risk ratios and risk differences along with 95% credible intervals were conducted.
Abstract: Importance Treatment with noninvasive oxygenation strategies such as noninvasive ventilation and high-flow nasal oxygen may be more effective than standard oxygen therapy alone in patients with acute hypoxemic respiratory failure. Objective To compare the association of noninvasive oxygenation strategies with mortality and endotracheal intubation in adults with acute hypoxemic respiratory failure. Data Sources The following bibliographic databases were searched from inception until April 2020: MEDLINE, Embase, PubMed, Cochrane Central Register of Controlled Trials, CINAHL, Web of Science, and LILACS. No limits were applied to language, publication year, sex, or race. Study Selection Randomized clinical trials enrolling adult participants with acute hypoxemic respiratory failure comparing high-flow nasal oxygen, face mask noninvasive ventilation, helmet noninvasive ventilation, or standard oxygen therapy. Data Extraction and Synthesis Two reviewers independently extracted individual study data and evaluated studies for risk of bias using the Cochrane Risk of Bias tool. Network meta-analyses using a bayesian framework to derive risk ratios (RRs) and risk differences along with 95% credible intervals (CrIs) were conducted. GRADE methodology was used to rate the certainty in findings. Main Outcomes and Measures The primary outcome was all-cause mortality up to 90 days. A secondary outcome was endotracheal intubation up to 30 days. Results Twenty-five randomized clinical trials (3804 participants) were included. Compared with standard oxygen, treatment with helmet noninvasive ventilation (RR, 0.40 [95% CrI, 0.24-0.63]; absolute risk difference, −0.19 [95% CrI, −0.37 to −0.09]; low certainty) and face mask noninvasive ventilation (RR, 0.83 [95% CrI, 0.68-0.99]; absolute risk difference, −0.06 [95% CrI, −0.15 to −0.01]; moderate certainty) were associated with a lower risk of mortality (21 studies [3370 patients]). Helmet noninvasive ventilation (RR, 0.26 [95% CrI, 0.14-0.46]; absolute risk difference, −0.32 [95% CrI, −0.60 to −0.16]; low certainty), face mask noninvasive ventilation (RR, 0.76 [95% CrI, 0.62-0.90]; absolute risk difference, −0.12 [95% CrI, −0.25 to −0.05]; moderate certainty) and high-flow nasal oxygen (RR, 0.76 [95% CrI, 0.55-0.99]; absolute risk difference, −0.11 [95% CrI, −0.27 to −0.01]; moderate certainty) were associated with lower risk of endotracheal intubation (25 studies [3804 patients]). The risk of bias due to lack of blinding for intubation was deemed high. Conclusions and Relevance In this network meta-analysis of trials of adult patients with acute hypoxemic respiratory failure, treatment with noninvasive oxygenation strategies compared with standard oxygen therapy was associated with lower risk of death. Further research is needed to better understand the relative benefits of each strategy.
259 citations