New research from Massey University’s College of Health has shed light on how an emerging therapy for respiratory support works something that benefit patients with obstructive sleep apnoea, chronic obstructive pulmonary disease and others that require acute or long-term respiratory support. Acute respiratory distress syndrome (ARDS) is a common condition in intensive care unit patients and remains a major concern, with mortality rates of around 30–45% and considerable long-term morbidity.
Ventilator induced lung injury
Nasal high flow (NHF) is define as humidify gas deliver at a flow; so greater than 15 litres per minute through a nasal cannula that maintains or improves patient comfort. Respiratory disease is the third leading cause of death in New Zealand, affecting one in six Kiwis at an annual cost of approximately $6 billion.
Associate Professor Toby Mündel from the School of Sport; so Exercise and Nutrition says some evidence points to NHF being as effective as non-invasive ventilation in acute respiratory failure; also superior to conventional oxygen therapy for long-term treatment of respiratory disease. However, They adds, most of the previous research in this area has been perform on patient populations that may be confound by disease specific factors.
Purge the upper airways
They know that a major mechanism of NHF is to purge the upper airways of expire air and replace it with fresher gas; but we don’t know how this exactly works. Another complication is that whilst we are awake; behavioural influences can mask the real effect and mechanism of NHF; so therefore studying these effects during sleep is the prefer setting.
Dr. Mundel and long-time collaborator Dr. Stanislav Tatkov; so clinical research manager at Fisher & Paykel Healthcare, measure ventilation in healthy young males during sleep; where they increase the amount of carbon dioxide drawn into the NHF gas. The results show that NHF reduce ventilation during sleep as a result of smaller; but more efficient breaths, cause by a reduction in the re breathing of carbon dioxide; hence from dead space inhale air that does not reach the lungs, and is therefore not use for gas exchange.
These findings help explain why and how acute and chronic care patients; so receiving respiratory support with NHF display de-escalation of care and improve health related quality of life; namely by increasing breathing efficiency and reducing waste ventilation; which should unload respiratory muscles to decrease the work of breathing,” Dr. Mundel says.