High Flow Nasal Oxygen as a Treatment Option for Acute Respiratory Distress Syndrome in Coronavirus (COVID-19) Infection

The 2019–20 coronavirus pandemic [1], is an ongoing pandemic of coronavirus disease 2019 (COVID-19) with severe acute respiratory syndrome as the main cause for morbidity and mortality [2,3]. The World Health Organization declared the outbreak to be a Public Health Emergency of International Concern on 30 January 2020, and recognized it as a pandemic on 11 March 2020 [4]. There are suggested therapeutic protocols for diff erent stages of the disease [5]. However the timing of intubation and use of high fl ow nasal oxygen support are still nonconclusive at this point [6,7].


Introduction
The 2019-20 coronavirus pandemic [1], is an ongoing pandemic of coronavirus disease 2019 (COVID-19) with severe acute respiratory syndrome as the main cause for morbidity and mortality [2,3]. The World Health Organization declared the outbreak to be a Public Health Emergency of International Concern on 30 January 2020, and recognized it as a pandemic on 11 March 2020 [4]. There are suggested therapeutic protocols for diff erent stages of the disease [5]. However the timing of intubation and use of high fl ow nasal oxygen support are still nonconclusive at this point [6,7].

Case
A confi rmed case of COVID-19 patient, 56-year-old man, was admitted to the department of CORONA B in Hasharon hospital. The patient was complaining of fever up to 38 0 C, dry cough and dyspnea. He has a past medical history of obstructive sleep apnea (OSA) anxiety and heavy smoking. His current treatment at home includes using Continuous Positive Airway Pressure (CIPAP) mask and Venlafaxine 150mg (for anxiety) daily. He denies any other diseases including heart disease or heart failure. His symptoms of fever and sore throat began 5 days before admission and the patient was treated at home with oral antibiotics Zinnat 500 mg by his family physician with mild improvement and on the 6 th day when his symptoms of sore throat, cough, and chest distress accompanied with progressive dyspnea he was tested by oropharyngeal swab test of SARS-CoV-2, qualitative real-time reverse-transcriptasepolymerase-chain-reaction (RT-PCR) assay and was found positive for COVID-19 and was admitted to our department. On admission, his physical examination revealed subclinical fever

Abstract
The ongoing outbreak of COVID-19 that began in Wuhan, China, has constituted a Public Health Emergency of International Concern, with cases confi rmed in multiple countries. The outbreak of COVID-19 in Israel, in March 2020 caused major changes in the routine work in hospitals mainly internal medicine wards . Hasharon hospital, a small community hospital in Petah Tikva was converted to corona patients admissions only. In accordance with this new reality internal medicine B department prepared itself to provide treatments tailored to the clinical needs of the Covid 19 patients and the quarantine conditions of these patients hospitalization. We report a confi rmed case of COVID-19 who was diagnosed with ARDS and refused intubation. He was treated with High Flow Nasal Oxygen (HFNO) combined with medication and physiotherapy with very good results. This case highlights the importance of non-Invasive ventilation treatment. DIDimer 1310 ng/ml ( normal range 0-500 ng/ml) (Figures 1-4).

High Flow Nasal
Chest X Ray showed bilateral interstitial ground glass fi nding diagnosed as severe ARDS ( Figure 5).
At this point we consulted intensive care unit expert and the decision was to intubate the patient and start mechanical ventilation support. However, the patient became agitated and refused intubation and since the patient was alert and conscious, we decided to try High Flow Nasal Oxygen along with physiotherapy treatment and assurance of the patient. The whole process was performed via video cameras from outside the ward and a small team of staff near the patient. Since the patient was a former heavy smoker he was treated with Intravenous hydrocortisone 150 mg/once. Oxygen saturation improved immediately and the patient was able to maintain saturation of 95-96% by HFNO support. In the next few days the patient condition continued to improve, his respiratory symptoms improved, and he maintained normal body temperature. Four days later the patient was able to keep saturation with nasal oxygen tube and physiotherapy guidance via telemedicine.
Blood test shows improvement of lymphopenia: absolute lymphocyte count was 1700 micl (24%) on day 8, and went back to normal (2700 micl -31%) on day 12. DIDimer and CRP dropped to normal rang on day 11 and ferritin level was 470 ng/ml. Negative PCR test for COVID-19 was found in 2 consecutive tests and the patient was declared as non-active COVID 19 and was discharged home with oxygen and physiotherapy support. Two weeks later the patient reports of much better improvement, he only uses nasal oxygen at night and he is gradually going back to his normal activities.

Discussion
High fl ow nasal oxygen (HFNO) is a non-invasive respiratory support modality that delivers high fl ow (liters per minute) medical oxygen to a patient through an interface (nasal cannula) intended to create a wash-out of the upper airway. The applied gas is heated to best match human body temperature (37°C) and humidifi ed targeting ideal body saturation vapor pressure [7,8].
Oxygenation is achieved by providing an increased FiO2 in the air fl ow to the patient. The constant fl ush of the upper airway creates a reservoir that reduces room-air entrainment to such an amount that it becomes a true fraction of inspired oxygen as set by the device [8].    Among patients with acute hypoxemic respiratory failure, HFNO was proven to avoid intubation compared to conventional oxygen device [9]. However, there is major concern that HFNO may increase bio-aerosol dispersion in the environment due to the high gas fl ow used. were treated with HFNO with good results [11].
We described a patient who deteriorated to severe ARDS and we had to decide quickly on the method of respiratory support. Since he was alert and conscious and did not agree to intubation we decided to support him with HFNO combined with physiotherapy and one dose of corticosteroids with good clinical and laboratory results.

Conclusion
HFNO treatment provided to the right patient can improve respiratory treatment and avoid intubation even in ARDS.
Further clinical studies are needed to truly evaluate aerosol dispersion and aerosol dynamics during physiological exhalation and cough in COVID 19