Coppo, Anna et al. The Lancet Respiratory Medicine. 2020; Volume 8, Issue 8, 765-774
This prospective cohort study aimed to assess the feasibility and effect on gas exchange of prone positioning in 56 awake, non-intubated patients with COVID-19-related pneumonia. Several variables were evaluated including demographics, anthropometrics, arterial blood gas, and ventilation parameters. The primary measured outcome was the variation in oxygenation between baseline and resupination, which served as an index of pulmonary recruitment. Findings have shown that prone positioning in awake, spontaneously breathing patients is achievable outside of the critical care environment in the majority of the patients. Improvements have been observed in oxygenation via Helmet CPAP interface (n=44), reservoir mask (n=9) and Venturi mask (n=3), during prone position, which was preserved upon resupination by half of the patients for 1 hour or more, as well as non-significant reduction in dyspnoea. Furthermore, patient discomfort was minimal and prone position was found to be a valuable patient engaging technique that improved blood gas parameters in the short term in patients with COVID-19-related pneumonia.
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Longhini F, Bruni A, Garofalo E, et al. Pulmonology. 2020;26(4):186-191
This study set out to investigate the safety and efficacy of combining helmet CPAP (hCPAP) and prone position in order to avoid deterioration of gas exchange and intubation in patients with COVID-19 induced pneumonia. Preliminary results from an ongoing study in COVID-19 patients, measuring tidal volume during hCPAP, showed a low mean tidal volume, high pulmonary compliance and low respiratory rate, which translates in a low transpulmonary pressure. At this stage the real effects and efficacy of hCPAP from the pathophysiological stand point is not known. In healthy patients, findings suggest that redistribution of perfusion could improve oxygenation in patients lacking hypoxic vasoconstriction. If the hypothesis presented in this study is confirmed, this may reduce the requirement for endotracheal intubation, invasive mechanical ventilation, hospital length of stay and improving the survival rates. Moreover, it could also reduce the need for ICU beds, which can be substituted by sub-intensive beds.
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Ferioli M, Cisternino C, Leo V, Pisani L, Palange P, Nava S. Eur Respir Rev. 2020 Apr 3;29(155):200068
The objective of this paper is to provide evidence-based recommendations for the correct use of respiratory devices in the COVID-19 emergency and protect healthcare workers from contracting the SARS-CoV-2 infection. Current evidence shows that around 20% of COVID-19 patients develop a severe Respiratory Distress Syndrome, which in almost a third of the cases requires respiratory support treatment. This type of support includes the use of oxygen therapy, HFNC, CPAP and NIV, which are non-invasive methods with a high risk of aerosol dispersion, especially in unprotected environments. Amongst those methods of delivery of non-invasive respiratory support, the use of a respiratory helmet with an inflatable neck cushion represents the safest option. In addition, data suggest that respecting the indications for the use of PPE is effective in preventing infections among healthcare workers, as demonstrated in a case–control study conducted during the SARS epidemic in Hong Kong. This study investigated the effective adhesion of personnel to PPE (gloves, disposable shirts, goggles and masks) and reported that none of the staff using all the safety measures contracted the virus, while all the infected staff had omitted at least one of them. Therefore, the helmet with neck cushion to treat infected patients with severe respiratory distress syndrome and PPE measures by the personnel must be adopted to prevent the spreading of infection amongst other patients and medical personnel.
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Hui DS, Chow BK, Lo T, Ng SS, Ko FW, Gin T, Chan MTV. Chest. 2015 May;147(5):1336-1343.
This study set out to determine the extent of exhaled air dispersion, which is linked to the rate of nosocomial infections, when employing NIV using a high-fidelity human patient simulator. Two different helmets and one face mask were put to the test, which included the Sea-Long Medical Systems helmet, the StarMed CaStar R helmet and a Koninklijke Philips total facemask. Exhaled air was evaluated in a negative pressure room with 12 air changes/h by two different helmets via a ventilator and a total facemask via a bilevel positive airway pressure device. Exhaled air was labelled by intrapulmonary smoke particles, illuminated by laser light sheet, and captured through a camera for data analysis. Results have demonstrated that during NIV via the Sea-Long Medical Systems helmet, exhaled air leaked through the neck seal reaching a radial distance of 150 to 230 mm. The patient simulator was programmed for mild lung injury and treated with inspiratory positive airway pressure from 12 to 20cm/H2O respectively and with expiratory pressure of 10cm/H2O. However, when delivering NIV via a StarMed CaStar R helmet with air cushion around the neck, air leakage was negligible. On the other hand, when administering NIV via a total face mask, air leaked through the exhalation port to a distance of 618 and 812 mm when inspiratory pressure was increased from 10 to 18 cm H2O, with the expiratory pressure at 5cm H2O. Therefore, using the helmet with a good seal around the neck represents the best option to prevent nosocomial infection during NIV for patients with respiratory infections.
Link to abstract.
Radovanovic D, Rizzi M, Pini S, Saad M, Chiumello DA, Santus P. J Clin Med. 2020;9(4):1191
The author of this research study proposes a management strategy for the treatment of acute hypoxemic respiratory failure in patients with COVID-19. Respiratory support with NIV or high flow oxygen should be avoided to limit droplets/virus aerosolisation and healthcare worker contamination. Therefore, the implementation of CPAP through a helmet system may provide an effective and safer alternative to improve hypoxemia. In addition, the use of the helmet will also reduce room contamination and improve patient comfort, while guaranteeing better clinical assistance and long term tolerability. However, careful CPAP titration must be provided to better optimise the recruitment of unventilated lung sections to improve patient outcomes.