Comparison of Comfort and Effectiveness of Total Face Mask and Oronasal Mask in Noninvasive Positive Pressure Ventilation in Patients with Acute Respiratory Failure: A Clinical Trial

Comparative evaluation of three total full-face masks for delivering Non-Invasive Positive Pressure Ventilation (NPPV): a bench study

Historically, the oro-nasal mask has been the preferred interface to deliver Non-Invasive Positive Pressure Ventilation (NPPV) in critically ill patients. To overcome the problems related to air leaks and discomfort, Total Full-face masks have been designed. No study has comparatively evaluated the performance of the total Full-face masks available.The aim of this bench study was to evaluate the influence of three largely diffuse models of total Full -face masks on patient-ventilator synchrony and performance during pressure support ventilation. NPPV was applied to a mannequin, connected to an active test lung through three largely diffuse Full-face masks: Dimar Full-face mask (DFFM), Performax Full-face mask (RFFM) and Pulmodyne Full-face mask (PFFM).The performance analysis showed that the ΔPtrigger was significantly lower with PFFM (p < 0.05) at 20 breaths/min (RRsim) at both pressure support (iPS) levels applied, while, at RRsim 30, DFFM had the longest ΔPtrigger compared to the other 2 total full face masks (p < 0.05). At all ventilator settings, the PTP200 was significantly shorter with DFFM than with the other two total full-face masks (p < 0.05). In terms of PTP500 ideal index (%), we did not observe significant differences between the interfaces tested.The PFFM demonstrated the best performance and synchrony at low respiratory rates, but when the respiratory rate increased, no difference between all tested total full-face masks was reported.

Ventilation of ordinary face masks

Wearing of face masks has been identified as an essential means of reducing COVID-19 infection during the pandemic. However, air leakage into ordinary face masks decreases the protection they provide. Wearing a mask also causes both CO₂ and humidity to accumulate inside, imposing breathing difficulty and discomfort. To remedy the above problems, this investigation proposed to ventilate ordinary masks by supplying additional HEPA filtered air. The N95, surgical, and cotton masks available on the market, were modified into ventilated masks. The air inside the masks was extracted for measurement of the PM_2.5, CO₂, and water vapor concentrations. The protection provided by the masks was evaluated in terms of their effectiveness in shielding wearers from ambient PM_2.5. Mask comfort was examined in terms of both CO₂ concentration and humidity ratio. In addition, a mathematical model was established to solve for the exchanged air flow rates via different routes. Subjective voting by 20 mask wearers was also conducted. Performance of the ventilated face masks were compared against the non-ventilated ones. It was found that the protection provided by the ordinary non-ventilated masks is much lower than that claimed for the filter materials alone due to significantly total inward leakage. The accumulated CO₂ and humidity inside masks resulted in discomfort and complaints. For contrast, the ventilated face masks not only enhanced protection by suppressing the inward leakage of ambient airborne particles, but also significantly improved comfort. The wearers preferred a filtered air flow rate ranging from 18 to 23 L/min.

Failure of non-invasive respiratory support after 6 hours from initiation is associated with ICU mortality

A previous study has shown that late failure (> 48 hours) of high-flow nasal cannula (HFNC) was associated with intensive care unit (ICU) mortality. The aim of this study was to investigate whether failure of non-invasive respiratory support, including HFNC and non-invasive positive pressure ventilation (NPPV), was also associated with the risk of mortality even if it occurs in the earlier phase. We retrospectively analyzed 59 intubated patients for acute respiratory failure due to lung diseases between April 2014 and June 2018. We divided the patients into 2 groups according to the time from starting non-invasive ventilatory support until their intubation: ≤ 6 hours failure and > 6 hours failure group. We evaluated the differences in the ICU mortality between these two groups. The multivariate logistic regression analysis showed the highest mortality in the > 6 hours failure group as compared to the ≤ 6 hours failure group, with a statistically significant difference (p < 0.01). It was also associated with a statistically significant increased 30-day mortality and decreased ventilator weaning rate. The ICU mortality in patients with acute respiratory failure caused by lung diseases was increased if the time until failure of HFNC and NPPV was more than 6 hours.

Mask interfaces for home non-invasive ventilation in infants and children

The selection of the mask interface for non-invasive ventilation (NIV) is recognized to be an essential part for therapy success. While nasal masks are the first recommended option in children and adults, there are indications for other mask types such as intolerance or complications from nasal masks. Evidence comparing performance, adherence and complication risk among mask interfaces in pediatrics is, however, scarce and information is often extrapolated from adult studies. Given this gap in knowledge and the lack of guidelines on NIV initiation in children, mask selection often relies on the clinicians' knowledge and expertise. Careful mask selection, a well-fitting headgear and time investment for mask desensitization are some important recommendations for adequate mask adaptation in children. Frequent mask-related complications include nasal symptoms, unintentional leak, mask displacement, skin injury, and midface hypoplasia. Close monitoring and a pro-active approach may help to minimize complications and promote the optimal use of home NIV.

Non-invasive ventilation practices in children across Europe

OBJECTIVES

To describe the diversity in practice in non-invasive ventilation (NIV) in European pediatric intensive care units (PICUs).

WORKING HYPOTHESIS

No information about the use of NIV in Pediatrics across Europe is currently available, and there might be a wide variability regarding the approach.

STUDY DESIGN

Cross-sectional electronic survey.

METHODOLOGY

The survey was distributed to the ESPNIC mailing list and to researchers in different European centers.

RESULTS

One hundred one units from 23 countries participated. All respondent units used NIV. Almost all PICUs considered NIV as initial respiratory support (99.1%), after extubation (95.5% prophylactically, 99.1% therapeutically), and 77.5% as part of palliative care. Overall NIV use outside the PICUs was 15.5% on the ward, 20% in the emergency department, and 36.4% during transport. Regarding respiratory failure cause, NIV was delivered in pneumonia (97.3%), bronchiolitis (94.6%), bronchospasm (75.2%), acute pulmonary edema (84.1%), upper airway obstruction (76.1%), and in acute respiratory distress syndrome (91% if mild, 53.1% if moderate, and 5.3% if severe). NIV use in asthma was less frequent in Northern European units in comparison to Central and Southern European PICUs (P = 0.007). Only 47.7% of the participants had a written protocol about NIV use. Bilevel NIV was applied mostly through an oronasal mask (44.4%), and continuous positive airway pressure through nasal cannulae (39.8%). If bilevel NIV was required, 62.3% reported choosing pressure support (vs assisted pressure-controlled ventilation) in infants; and 74.5% in older children.

CONCLUSIONS

The present study shows that NIV is a widespread technique in European PICUs. Practice across Europe is variable.

High-Frequency Jet Ventilation in Nonintubated Patients

OBJECTIVES

High-frequency jet ventilation (HFJV) is a convenient method for providing ventilation during fiberoptic bronchoscopy. We describe an incipient approach of high-frequency jet ventilation via the working channel of a flexible bronchoscope for nonintubated patients who suffer from hypoxemia during bronchoscopy. The aim of this study was to test the efficacy of this incipient approach and determine the possible complications related to it.

MATERIALS AND METHODS

Sixteen patients who had oxygen saturation below 70% that did not resolve with nasal oxygen for 20 s during interventional bronchoscopy were included in the study. High-frequency jet ventilation was administrated via the working channel of a bronchoscope for 3 min. Arterial blood gas circumscriptions were compared before and after jet ventilation.

RESULTS

Oxygen saturation increased to >90% in all patients 30 s after jet ventilation. Mean arterial oxygen saturation pressure increased from 54.84 to 111.98 mmHg with jet ventilation (p=0.0001). Arterial carbon dioxide tension decreased after jet ventilation. The body mass index had no consequential effect on arterial carbon dioxide pressure after jet ventilation in our patients (p=0.1). Complications such as pneumothorax and working channel damage were not observed.

CONCLUSION

High-frequency jet ventilation via the working channel of the bronchoscope is a novel method that can provide optimal ventilation with minimal complications to nonintubated patients suffering from hypoxemia during bronchoscopy. This method also reduces the duration of bronchoscopy procedures.