Work of breathing using different interfaces in spontaneous positive pressure ventilation: helmet, face-mask, and endotracheal tube

Validation of Airway Occlusion Pressure as a Method of Assessing Breathing Effort During Noninvasive Ventilation

Background: The airway-occlusion pressure is used to estimate the muscle pressure (P mus ) and the occlusion pressure at 100 ms (P 0 .1 ) to assess respiratory drive in patients on mechanical ventilation. However, the validity of these maneuvers during noninvasive ventilation (NIV) has not been evaluated. This study was designed to validate the airway-occlusion pressure and the P 0 .1 described for mechanical ventilation during NIV in a bench model. Methods: This was a bench observational prospective study carried out during January and February 2024 in the ICU laboratory of the Hospital Británico of Buenos Aires. Results: In the non-leakage NIV scenarios with oronasal and total face mask, the NIV-airway-occlusion pressure increased with greater P mus (P < .001). For a programmed P mus of 5 cm H2O, values around 4.5 cm H2O were recorded for both oronasal and total face masks. At 10 cm H2O, the values were ∼8 cm H2O, and at 15 cm H2O, they were ∼11 cm H2O. With leaks, this difference worsened as leakage increased and the effort decreased. In the Bland-Altman analysis between mechanical ventilation-airway-occlusion pressure and NIV-airway-occlusion pressure without leakage for oronasal and total face masks, we found a good agreement for the 3 levels of P mus with both types of masks. With regard to the values of NIV-airway-occlusion pressure with the helmet, Bland-Altman analysis showed a high bias and random error. Multivariate analysis found that NIV-airway-occlusion pressure depends on the type of interface, increased with P mus , and decreased as leakage increased. The agreement of NIV-P 0 .1 was not good across all noninvasive measurements. Conclusions: This study constitutes a relevant contribution in the validation of indices to assess P mus during NIV. In a laboratory setting, the measurement of airway-occlusion pressure in NIV may be used to assess effort estimation in the absence of leakage; however, it will likely be underestimated. P 0 .1 proved to be an unreliable method. These findings suggest the feasibility of assessing muscle effort during NIV.

Characteristics and risk factors of facial pressure injuries in acute inpatients using noninvasive positive pressure ventilation: A retrospective case control study

OBJECTIVE

To explore the characteristics and risk factors of facial pressure injuries in patients using noninvasive positive pressure ventilation.

SETTING AND SAMPLE

Patients who developed facial pressure injuries due to non-invasive positive pressure ventilation at a teaching hospital in Taiwan from January 2016 to December 2021 were selected, resulting in a total of 108 patients in our case group. A control group was formed by matching each case by age and gender to three acute inpatients who had used non-invasive ventilation but had not developed facial pressure injuries, resulting in 324 patients in the control group.

RESEARCH METHODOLOGY

This study was a retrospective case-control study. The characteristics of the patients who developed pressure injuries at different stages in the case group were compared, and the risk factors of non-invasive ventilation-related facial pressure injuries were then determined.

RESULTS

Higher duration of non-invasive ventilation usage, higher length of hospital stay, lower Braden scale score, and lower albumin levels in the former group. The results of multivariate analysis from binary logistic regression involving the duration of non-invasive ventilation usage demonstrated that the patients who used this device for 4-9 days and 16 days were at greater risk of facial pressure injuries than those who used it for 3 days; in terms of the Braden scale score, higher Braden scale scores were correlated with a higher risk of facial pressure injuries. In addition, albumin levels lower than the normal range were correlated with a higher risk of facial pressure injuries.

CONCLUSION

Patients with pressure injuries at higher stages had a higher duration of non-invasive ventilation usage, higher length of hospital stay, lower Braden scale scores, and lower albumin levels. Thus, a longer duration of non-invasive ventilation use, lower Braden scale scores, and lower albumin levels were also risk factors for non-invasive ventilation-related facial pressure injuries.

IMPLICATIONS FOR CLINICAL PRACTICE

Our results serve as a useful reference for hospitals, both in creating training programs for their medical teams to prevent and treat facial pressure injuries and in drafting guidelines for assessing risk in order to prevent facial pressure injuries caused by non-invasive ventilation. The duration of device usage, Braden scale scores, and albumin levels in particular should be seriously monitored to reduce the occurrence of facial pressure injuries in acute inpatients treated with non-invasive ventilation.

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.

Analogy between classical Yoga/Zen breathing and modern clinical respiratory therapy

Anesthesiologists and intensivists are modern-day professionals who provide appropriate respiratory care, vital for patient survival. Recently, anesthesiologists have increasingly focused their attention on the type of spontaneous breathing made by non-intubated patients with pulmonary disease cared for in an intensive care unit, and also patients with chronic pain receiving cognitive behavioral therapy. Prior to our modern understanding of respiratory physiology, Zen meditators recognized that breathing has a significant impact on a person’s mental state and general physical well-being. Examples of this knowledge regarding respiration include the beneficial effects of deep inhalation and slow exhalation on anxiety and general wellness. The classical literature has noted many suggestions for breathing and its psycho-physical effects. In the present review, we examine the effect of classical breathing methods and find an analogy between typical Yoga/Zen breathing and modern clinical respiratory therapy. Evidence is increasing about historical breathing and related meditation techniques that may be effective in modern clinical practice, especially in the field of anesthesiology, such as in improving respiratory function and reducing chronic pain. Clarification of the detailed mechanisms involved is anticipated.