Noise Level and Comfort in Healthy Subjects Undergoing High-Flow Helmet Continuous Positive Airway Pressure

Patients' recollections of helmet-CPAP treatment during COVID-19 pandemic: A qualitative study

BACKGROUND

During the pandemic outbreak, helmet continuous positive airway pressure (CPAP) was widely used as respiratory support for COVID-19 patients, inside and outside of intensive care units. The available literature suggests specific interventions to improve the comfort of patients treated with helmet-CPAP. Few reports are available on the experiences of patients undergoing this treatment.

AIM

This qualitative study aimed to explore the views and recollections of COVID-19 patients undergoing helmet-CPAP.

STUDY DESIGN

We conducted semi-structured interviews with thematic analysis. Participants were recruited from the follow-up programme for COVID-19 patients discharged from an Italian general intensive care unit. Participants were interviewed by telephone. Data analysis followed the principles of thematic synthesis approach.

FINDINGS

We conducted 29 phone calls in patients eligible for the study. Five participants declared that they did not remember the time spent in hospital on helmet-CPAP. Twenty-four patients were then included. Two themes and six subthemes were generated from their interview data: (1) The helmet-CPAP as a life-saving treatment (subthemes: recognition of the usefulness of treatment and resilience); (2) the negative feelings related to helmet-CPAP application (subthemes: communication problems, entrapment, mental confusion, fear of dying). Each patient's experience was unique, but some discomfort elements such as noise, gas flow turbulence, choking sensation and thirst were found to be very common.

CONCLUSIONS

The application of helmet-CPAP treatment generated positive and negative memories and feelings in COVID-19 patients during the pandemic. The patients' experience has provided an overview of the main factors of discomfort. This can be a starting point for taking corrective measures to promote greater helmet tolerance and subsequent treatment success.

RELEVANCE TO CLINICAL PRACTICE

This study has provided an insight into the patient's recollections about helmet-CPAP treatment during a worldwide pandemic. The findings suggested strict applications of interventions aimed to reduce some issues that participants reported, to improve their compliance to treatment. Results from this study could help nurses in understanding the needs of patients treated with helmet-CPAP and may foster a care focused on patient-centred outcomes.

A technique to measure tidal volume during noninvasive respiratory support by continuous-flow helmet CPAP

PURPOSE

The coronavirus disease 2019 (COVID-19) pandemic has promoted the use of helmet continuous positive airway pressure (CPAP) for noninvasive respiratory support in hypoxic respiratory failure patients, despite the lack of tidal volume monitoring. We evaluated a novel technique designed to measure tidal volume during noninvasive continuous-flow helmet CPAP.

METHODS

A bench model of spontaneously breathing patients undergoing helmet CPAP therapy (three positive end-expiratory pressure [PEEP] levels) at different levels of respiratory distress was used to compare measured and reference tidal volumes. Tidal volume measurement by the novel technique was based on helmet outflow-trace analysis. Helmet inflow was increased from 60 to 75 and 90 L/min to match the patient's peak inspiratory flow; an additional subset of tests was conducted under the condition of purposely insufficient inflow (i.e., high respiratory distress and 60 L/min inflow).

RESULTS

The tidal volumes examined herein ranged from 250 to 910 mL. The Bland‒Altman analysis showed a bias of -3.2 ± 29.3 mL for measured tidal volumes compared to the reference, corresponding to an average relative error of -1 ± 4.4%. Tidal volume underestimation correlated with respiratory rate (rho = .411, p = .004) but not with peak inspiratory flow, distress, or PEEP. When the helmet inflow was maintained purposely low, tidal volume underestimation occurred (bias - 93.3 ± 83.9 mL), corresponding to an error of -14.8 ± 6.3%.

CONCLUSION

Tidal volume measurement is feasible and accurate during bench continuous-flow helmet CPAP therapy by the analysis of the outflow signal, provided that helmet inflow is adequate to match the patient's inspiratory efforts. Insufficient inflow resulted in tidal volume underestimation. In vivo data are needed to confirm these findings.

Helmet continuous positive airway pressure for patients' transport using a single oxygen cylinder: A bench study

BACKGROUND

Continuous positive airway pressure (CPAP) is frequently used to treat patients with acute respiratory failure in out-of-hospital settings. Compared to a facemask, the helmet has many advantages for the patient but requires a minimum gas flow of 60 L/min to avoid CO2 rebreathing. The aim of the present bench study was to evaluate the performance of four Venturi devices, connected to a single oxygen cylinder, in delivering helmet-CPAP with clinically relevant gas flow, fraction of inspired oxygen (FiO2), and positive end-expiratory pressure (PEEP) values.

METHODS

Three double-inlet Venturi systems (EasyVent, Ventuplus, Compact-HAR) were connected to full 5-L oxygen cylinders using a double flowmeter, and their oxygen requirements to reach different setups (flow 60-80 L/min; FiO2 0.4-0.5-0.6, PEEP 7.5-10-12.5 cmH2O) were tested. The fourth Venturi system (O2-MAX) was directly attached to the tank, and the flow and FiO2 delivered at preset FiO2 0.3 and 0.6 were recorded. The runtime of the cylinder was assessed.

RESULTS

EasyVent, Ventuplus, and O2-MAX were able to deliver helmet-CPAP with clinically useful setups when connected to a single oxygen cylinder, while Compact-HAR did not. The runtime of the cylinders ranged between 28 and 60 minutes according to the preset flow and FiO2. The delivered gas flow decreased slowly and linearly with the drop in cylinder pressure until its exhaustion.

CONCLUSIONS

Helmet-CPAP might be provided using portable Venturi systems connected to an oxygen cylinder, but not all of them are able to deliver it. The use of a double flowmeter allows delivery of both high flow and high FiO2 when double-inlet Venturi systems are used. Due to the flow drop observed during the cylinder consumption, a flow >60 L/min should be set when helmet-CPAP is started. Considering the flow drop phenomenon, the estimated duration of the tank runtime can be used with a margin of safety when planning patient transport.

Helmet Continuous Positive Airway Pressure in the Emergency Department: A Practical Guide

Helmet continuous positive airway pressure is a simple, noninvasive respiratory support strategy to treat several forms of acute respiratory failure, such as cardiogenic pulmonary edema and pneumonia. Recently, it has been largely used worldwide during the COVID-19 pandemic. Given the increased use of helmet continuous positive airway pressure in the emergency department, we aimed to provide an updated practical guide for nurses and clinicians based on the latest available evidence. We focus our attention on how to set the respiratory circuit. Moreover, we discuss the interactions between flow generators, filters, and positive end-expiratory pressure valves and the consequences regarding the delivered gas flow, fraction of inspired oxygen, positive end-expiratory pressure, and noise level.

Sound and Light Levels in a General Intensive Care Unit Without Windows to Provide Natural Light

BACKGROUND

Appropriate levels and patterns of sound and light in an intensive care room help to maintain the patient's normal physiological functions. High sound levels can disrupt the patient's normal sleep architecture, cause hearing deficits, and induce the onset of delirium. Intensive care unit patients frequently report poor sleep, partly due to the environment.

OBJECTIVES

An observational pilot prospective study was designed to record sound pressure and light pollution levels in an Italian intensive care unit, without windows to provide natural light.

METHOD

Sound levels were measured in decibel A (dBA) every 10 seconds. Sound data were analyzed for sound peak, defined as the number of times sound levels exceeded 45, 50, 60, 65, 70, 75, 80, and 85 dBA. Light measures were taken every 10 seconds on a continuous basis. Light data were analyzed for light "peaks," defined as the number of times light levels exceeded 100, 200, 300, 400, and 500 lux.

RESULTS

The overall median sound level during the study period was equal to 54.60 (interquartile range [IQR], 51.70-57.70) dBA. The daytime median sound level was 56.00 (IQR, 53.00-59.50) dBA, and the nighttime median was 53.00 (IQR, 49.50-55.20) dBA (P < .001). The overall median light level was equal to 114 (IQR, 0-225) lux. The daytime median light level was 184 (IQR, 114-293) lux, and the nighttime median was 0 (IQR, 0-50) lux (P < .001). With respect to room lighting, rooms were observed to have "no lights on" 12.6% of daytime and 41% of nighttime.

DISCUSSION

The sound levels recorded in our sample demonstrated that peaks >45 dBA during daytime and nighttime are, respectively, equal to 99.9% and 98.6% of all readings. The Environmental Protection Agency/World Health Organization recommended thresholds for both day (45 dBA) and night (35 dBA). Sound levels reached "toxic levels" when sound-generating activities were performed by nurses and physicians.

Helmet CPAP in the emergency department: A narrative review

BACKGROUND

The choice of correct interface for the right patient is crucial for the success of non-invasive ventilation (NIV) therapy. Helmet CPAP is a type of interface used to deliver NIV. Helmet CPAP improves oxygenation by keeping the airway open throughout the breathing cycle with positive end-expiratory pressure (PEEP).

OBJECTIVE

This narrative review describes the technical aspects and clinical indications of helmet continuous positive airway pressure (CPAP). In addition, we explore the advantages and challenges faced using this device at the Emergency Department (ED).

DISCUSSION

Helmet CPAP is tolerable than other NIV interfaces, provides a good seal and has good airway stability. During Covid-19 pandemic, there are evidences it reduced the risk of aerosolization. The potential clinical benefit of helmet CPAP is demonstrated in acute cardiogenic pulmonary oedema (ACPO), Covid-19 pneumonia, immunocompromised patient, acute chest trauma and palliative patient. Compare to conventional oxygen therapy, helmet CPAP had been shown to reduce intubation rate and decrease mortality.

CONCLUSION

Helmet CPAP is one of the potential NIV interface in patients with acute respiratory failure presenting to the emergency department. It is better tolerated for prolonged usage, reduced intubation rate, improved respiratory parameters, and offers protection against aerosolization in infectious diseases.

Helmet CPAP bundle: A narrative review of practical aspects and nursing interventions to improve patient's comfort

BACKGROUND

The application of Continuous Positive Airway Pressure (CPAP) with a helmet is increasing around the world, both inside and outside of the intensive care unit. Current published literature focus's on indications, contraindications and efficiency of Helmet CPAP in differing clinical scenarios. Few reports, summarising the available knowledge concerning technical characteristics and nursing interventions to improve patient's comfort, are available.

AIM

To identify the crucial technical aspects in managing patients undergoing Helmet-CPAP, and what nursing interventions may increase comfort.

METHODS

A narrative literature review of primary research published 2002 onwards. The search strategy comprised an electronic search of three bibliographic databases (Pubmed, Embase, CINAHL).

RESULTS

Twenty-three studies met the inclusion criteria and were included in the review. Research primarily originated from Italy. Nine key themes emerged from the review: gas flow management, noise reduction, impact of gas flow and HME filters on delivered FiO₂, filtration of exhaled gas / environmental protection, PEEP monitoring, airway pressure monitoring, active humidification of gas flow, helmet fixation and tips to implement awake prone position during Helmet-CPAP.

CONCLUSIONS

A Helmet-CPAP check-list has been made of nine key interventions based on the available evidence regarding system set up, monitoring and management. Implementation of this check-list may help nurses and physicians to increase the comfort of patients treated with Helmet CPAP and enhance their compliance with long-term treatment.

Flow generators for helmet CPAP: Which to prefer? A bench study

OBJECTIVE

To assess the different effect of filters' application during helmet-CPAP delivered with three different flow generators on the delivered fresh gas flow, FiO₂, and the noise level inside and outside the helmet.

METHODS

In a bench study, three flow generators (air-oxygen blender, turbine ventilator and Venturi system) were used to generate two different gas flows (60 L/min and 80 L/min), with a fixed FiO₂ at 0.6, to perform a helmet-CPAP on a manikin. Three different fixed PEEP valves (7.5, 10, and 12.5 cmH₂O) were applied at the expiratory port. Gas flow, FiO₂ and noise were recorded for each Flow-generator/Flow/PEEP combination, first without filter interposition and then after positioning a heat and moister exchanger filter (HMEF) at the helmet inlet port.

RESULTS

The application of the HMEF lead to a significant difference in the flow variation among the three flow generators (p < 0.001). Compared to baseline, the highest flow reduction was observed with the VENTURI (-13.4 ± 1.2 %, p < 0.001), a slight increase with the BLENDER (1.2 ± 0.5 %, p < 0.001), whereas no difference was recorded with the TURBINE (0.1 ± 0.6 %, p = 0.12). After HMEF was interposed, a significant FiO₂ variation was observed only with VENTURI (11.3 ± 1.8 %, p < 0.001). As for the noise, the TURBINE was the least noisy system, both with and without the filter interposition.

CONCLUSIONS

Flow generators used to deliver helmet-CPAP have different characteristics and responses to HMEF interposition. Users should be aware of the effects on FiO₂ and flow of the different devices in order to make a precise setup of the circuit.

Advantages and drawbacks of helmet noninvasive support in acute respiratory failure

INTRODUCTION

Non-invasive ventilation (NIV) represents an effective strategy for managing acute respiratory failure. Facemask NIV is strongly recommended in acute exacerbation of chronic obstructive pulmonary disease (AECOPD) with hypercapnia and acute cardiogenic pulmonary edema (ACPE). Its role in managing acute hypoxemic respiratory failure (AHRF) remains a debated issue. NIV and continuous positive airway pressure (CPAP) delivered through the helmet are recently receiving growing interest for AHRF management.

AREAS COVERED

In this narrative review, we discuss the clinical applications of helmet support compared to the other available noninvasive strategies in the different phenotypes of acute respiratory failure.

EXPERT OPINION

Helmets enable the use of high positive end-expiratory pressure, which may protect from self-inflicted lung injury: in AHRF, the possible superiority of helmet support over other noninvasive strategies in terms of clinical outcome has been hypothesized in a network metanalysis and a randomized trial, but has not been confirmed by other investigations and warrants confirmation. In AECOPD patients, helmet efficacy may be inferior to that of face masks, and its use prompts caution due to the risk of CO₂ rebreathing. Helmet support can be safely applied in hypoxemic patients with ACPE, with no advantages over facemasks.

Non-invasive Ventilation Delivered by Helmet vs Face Mask in Patients with COVID-19 Infection: Additional Measures to Reap Further Benefits

How to cite this article: Mandal M, Bhattacharya D, Esquinas AM. Non-invasive Ventilation Delivered by Helmet vs Face Mask in Patients with COVID-19 Infection: Additional Measures to Reap Further Benefits. Indian J Crit Care Med 2022;26(10):1159-1160.

Improving Helmet CPAP Use During COVID-19 Pandemic: A Multidisciplinary Approach in the Emergency Department

The aim of this article is to describe the importance of a multidisciplinary team dedicated to noninvasive ventilation training of the emergency department's staff. In our experience, the presence of a medical and nursing “noninvasive ventilation group” made it possible to quickly teach expertise on the management of noninvasive ventilation of COVID-19 patients among emergency department doctors and nurses. This allowed improving a standardized approach regarding the identification and ventilatory assistance of patients with SARS-CoV-2 pneumonia needing ventilatory support, the correct use of the devices, and quick identification and reduction of the complications associated with noninvasive ventilation.

In this article, we would like to encourage the formation of similar working groups in all situations where this is not yet present.

Role of helmet ventilation during the 2019 coronavirus disease pandemic

Coronavirus disease 2019 (COVID-19) has been declared a pandemic by the World Health Organization; it has affected millions of people and caused hundreds of thousands of deaths. Patients with COVID-19 pneumonia may develop acute hypoxia respiratory failure and require noninvasive respiratory support or invasive respiratory management. Healthcare workers have a high risk of contracting COVID-19 while fitting respiratory devices. Recently, European experts have suggested that the use of helmet continuous positive airway pressure should be the first choice for acute hypoxia respiratory failure caused by COVID-19 because it reduces the spread of the virus in the ambient air. By contrast, in the United States, helmets were restricted for respiratory care before the COVID-19 pandemic until the Food and Drug Administration provided the ‘Umbrella Emergency Use Authorization for Ventilators and Ventilator Accessories’. This narrative review provides an evidence-based overview of the use of helmet ventilation for patients with respiratory failure.

Helmet Ventilation for Pediatric Patients During the COVID-19 Pandemic: A Narrative Review

The air dispersion of exhaled droplets from patients is currently considered a major route of coronavirus disease 2019 (COVID-19) transmission, the use of non-invasive ventilation (NIV) should be more cautiously employed during the COVID-19 pandemic. Recently, helmet ventilation has been identified as the optimal treatment for acute hypoxia respiratory failure caused by COVID-19 due to its ability to deliver NIV respiratory support with high tolerability, low air leakage, and improved seal integrity. In the present review, we provide an evidence-based overview of the use of helmet ventilation in children with respiratory failure.

Investigating Noise Exposure to Newborn Infants From Respiratory Support: Methodological Considerations

Background and objective Excessive noise in the neonatal intensive care unit (NICU) may lead to serious long-term effects on hearing and sensory development in newborns. As such, the maximum allowed noise level is 45 A-weighted decibels (dBA). Studies regarding noise exposure to ventilated preterm infants show inconsistent results; however, these studies also vary considerably in their methodology in terms of noise ascertainment. We hypothesized that the study methodology can significantly influence data quality when measuring noise levels. In this study, we aimed to investigate whether the variations in ventilator noise levels in NICUs could be a result of methodological differences in study designs. Methods A ventilator circuit was set up using nasal continuous positive airway pressure (nCPAP) and high-frequency (HF) modes with nasal prongs. Noise levels were measured using a commercially calibrated noise meter. Three different scenarios were tested: (1) measurements were taken at different angles (0° to 180°), with 180° facing the end of the nasal prongs, without a mannequin, with the membrane/orifice of the noise meter placed 2 mm laterally from the prongs; (2) noise levels were measured at 180° at distances of 0-20 mm from the nasal prongs; (3) measurements were taken in the oral cavity of a life-size intubation mannequin of a newborn baby. Results Overall, the noise levels produced at different settings varied significantly, ranging from 45.7 dB to 82.2 dB. The average environmental background noise was 44.4 dB. Noise levels typically increased as the angle increased, with the highest noise level recorded at 180° for both HF and nCPAP modes, at 58.4 dB and 58.2 dB, respectively. Noise levels recorded at HF were slightly higher than nCPAP values. Furthermore, with regard to distance, the highest mean value, 82.2 dB, was recorded with the noise meter approximately 3 mm from the nasal prongs, and the lowest mean value, 47.6 dB, was recorded at ~20 mm. During trials with the mannequin, the lowest value, 50.1 dB, was recorded at the entrance of the mouth with slightly higher values being recorded within the oral cavity. Conclusion The results indicate that small changes in experimental settings, such as positioning and distance from the nasal prongs, can greatly influence noise levels, particularly above the recommended levels for neonates. These differences may be attributed to wind-generated noise. In summary, some study results are potentially influenced more by the study design than the device type or ventilator setting. We recommend further research and detailed reporting in the NICU to gain deeper insights into the topic.

The use of head helmets to deliver noninvasive ventilatory support: a comprehensive review of technical aspects and clinical findings

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.

[Influence of nurses on the experience of noninvasive ventilation]

Noninvasive ventilation (NIV) is established as an integral part of intensive care therapy for respiratory insufficiency. However, it is associated with restrictions on patient autonomy and comfort. A successful course of therapy is largely dependent on the acceptance and adherence of the patients concerned. Intensive care nurses can have a significant influence on the success of the therapy by dealing with the subjective experience of the patients and by maintaining close contact with them. The prerequisite for this is profound knowledge of the different technical aspects of therapy and equipment as well as positive and negative factors influencing NIV tolerance in order to be able to offer and implement an individual intervention.