Author: Samira Fard, BSc RRT CHT

Introduction

For patients with acute hypoxic respiratory failure, supplemental oxygen is an essential supportive therapy. Provision of this therapy is one of the leading causes of intensive care unit (ICU) admissions. There are multiple non-invasive approaches to reduce the risks involved with endotracheal intubation and mortality. Standard oxygen delivery systems deliver oxygen therapy with flow rates of less than 15 L/min. Non-invasive ventilation (NIV) via face mask or helmet interface has been an alternative method to minimize the risk of endotracheal intubation. NIV provides benefits in selected patients with acute respiratory failure requiring ICU admission; however, it is not greatly utilized in the ICU early on to garner its benefits and reduce the risk for endotracheal intubation.

In a network meta-analysis titled “Association of Noninvasive Oxygenation Strategies With All-Cause Mortality in Adults With Acute Hypoxemic Respiratory Failure”, the authors compared the difference between oxygen therapies: high-flow nasal oxygen, face mask non-invasive ventilation, helmet non-invasive ventilation, or standard oxygen therapy, with mortality and patients who received endotracheal intubation in adults with acute hypoxemic respiratory failure (Ferreryro et al., 2020). This paper was reviewed to illuminate the benefits of the use of NIV in combination with the helmet. The helmet has been deemed to enhance patient comfort and treatment tolerance. It may be an effective interface option for NIV.

Limitations and Conclusion

There are a  number of limitations in this study. First, in this network meta-analysis, there lies the assumption that comparable patient populations were enrolled in each trial and similar protocols were used in all the studies. Second, the execution of this network meta-analysis did not include combined study-level co-variates. Third, the possible cause of intrasensitivity can be represented by the range of severity of respiratory failure which is based on PaO2: FiO2 ratio. However, there is still consistency in the relative effects of the interventions. Fourth, the helmet had a high probability of being ranked first; however, ranking probabilities lack the certainty of the evidence, which was suspected to be low for comparisons with the helmet. Fifth, the blinding of the treatment group did not exist in the primary studies. And finally, the sixth limitation, the follow-up times for all causes of mortality in the studies varied; however, the sensitivity analyses produced similar results to the main analysis

Despite these limitations, the findings from this meta-analysis provide additional support for the use of NIV with the helmet interface to support acute respiratory failure in adult patients within ICU. Ferreryro et al. (2020), found that treatment of hypoxemic respiratory failure in adults with non-invasive oxygen therapies showed a reduced risk of death, the primary outcome, and endotracheal intubation, a secondary outcome, compared to the use of standard oxygen therapy. In this network meta-analysis of trials, it revealed the benefits of using the helmet interface to deliver oxygen in acute hypoxemic respiratory failure. The use of this particular modality, the helmet displayed decreased risk of intubation and mortality. Helmet non-invasive ventilation was

also found to physiologically enhance lung function by minimizing air leaks and as a result, potentially increasing alveolar recruitment and reducing respiratory effort. The use of the helmet improved patient tolerance and reduced therapy interruption compared with other strategies.

How it applies to RT

As a respiratory therapist (RT), the delivery of oxygen therapy is one of the primary aspects of the care we provide to our patients with acute hypoxemic respiratory failure. As a result of this network meta-analysis of trials, we can add more methods and strategies to provide oxygen therapy that can potentially enhance patient tolerance with the helmet interface and lead to a decrease in the chance of endotracheal intubation, longer hospital stays and mortality.

The Helmet Interface

The helmet interface is a hood that covers the entire head with a collar neck seal and is secured by two armpit braces. It has been suggested there are several advantages in utilizing this interface in comparison to a face mask, including the requirement of fewer disruption in the treatment and increasing longer application time, eliminating mask discomfort and skin lesions. There is a great improvement in patient comfort and thus tolerance, by eliminating the requirement for a seal around the mouth and nose and in turn, decreasing air leaks by improved seal integrity around the neck. As a result, positive airway pressure can be increased without the consequential air leak, which in turn can reduce the risk of intubation and mechanical ventilation.

Source: http://www.oxfordmedicaleducation.com/wp-content/uploads/2015/01/CPAP-hood.jpg

Future research

For the future, RTs can conduct further research on the helmet as a non-invasive modality from their perspective. They can focus on the use of the helmet by the RTs in regard to its application, initiation, time spent, and success of its use, and ultimately the benefit of the helmet for their patients.

Reference

Ferreyro, B. L., Angriman, F., Munshi, L., Del Sorbo, L., Ferguson, N. D., Rochwerg, B., … & Scales, D. C. (2020).
Association of Noninvasive Oxygenation Strategies With All-Cause Mortality in Adults With Acute Hypoxemic Respiratory Failure: A Systematic Review and Meta-analysis. JAMA, 324(1):57–67. doi:10.1001/jama.2020.9524