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Journal Pre-proof Nasal high flow oxygen therapy in COVID-19 patients does not cause environmental surface contamination Oriol Roca, MD, PhD, Andrés Pacheco, MD, Jordi Rodon, BSc, Andrés Antón, PhD, Júlia Vergara-Alert, PhD, Lluís Armadans, MD PhD, Joaquim Segalés, PhD, Tomás Pumarola, MD PhD, Magda Campins, MD PhD, Ricard Ferrer, MD PhD, Virginia Rodríguez-Garrido, PhD PII: S0195-6701(21)00216-4 DOI: https://doi.org/10.1016/j.jhin.2021.04.034 Reference: YJHIN 6414 To appear in: Journal of Hospital Infection Received Date: 14 February 2021 Revised Date: 29 April 2021 Accepted Date: 30 April 2021 Please cite this article as: Roca O, Pacheco A, Rodon J, Antón A, Vergara-Alert J, Armadans L, Segalés J, Pumarola T, Campins M, Ferrer R, Rodríguez-Garrido V, Nasal high flow oxygen therapy in COVID-19 patients does not cause environmental surface contamination, Journal of Hospital Infection, https://doi.org/10.1016/j.jhin.2021.04.034. 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Nasal high flow oxygen therapy in COVID-19 patients does not cause environmental surface contamination Oriol Roca MD, PhD1,2, Andrés Pacheco MD1, Jordi Rodon BSc3, Andrés Antón PhD4, Júlia Vergara-Alert PhD3, Lluís Armadans MD PhD4, Joaquim Segalés PhD5,6, Tomás Pumarola MD PhD4, Magda Campins MD PhD7, Ricard Ferrer MD PhD1,2, Virginia Rodríguez-Garrido f oo PhD4 r 1 -p Servei de Medicina Intensiva, Hospital Universitari Vall d’Hebron, Institut de Recerca Vall re d’Hebron, Barcelona, Spain. 2 Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBER), Madrid, lP Spain 3 IRTA, Centre de Recerca en Sanitat Animal (CReSA, IRTA-UAB), Campus de la Universitat Autònoma de Barcelona, Barcelona, Spain. na 4 Servei de Microbiologia, Hospital Universitari Vall d’Hebron, Institut de Recerca Vall d’Hebron, Barcelona, Spain 5 UAB, Centre de Recerca en Sanitat Animal (CReSA, IRTA-UAB), Campus de la Universitat ur Autònoma de Barcelona, Barcelona, Spain. 6 Departament de Sanitat i Anatomia Animals, Facultat de Veterinària, UAB, 08193 Bellaterra Jo (Cerdanyola del Vallès), Spain 7 Servei de Medicina Preventiva, Hospital Universitari Vall d’Hebron, Barcelona, Spain Corresponding author: Oriol Roca, MD, PhD Servei de Medicina Intensiva Hospital Universitari Vall d’Hebron Passeig de la Vall d'Hebron, 119-129 08035 Barcelona, Spain. E-mail: oroca@vhebron.net Declaration of Interests: None 1 To the Editor: Nasal high flow oxygen therapy (NHF) may spread the severe acute respiratory syndrome coronavirus (SARS-CoV-2) virus through respiratory droplets and contact with fomites. This concern leads to significant controversies regarding recommendations of its use in different evidence-based guidelines of therapy of coronavirus infectious disease 2019 (COVID-19) patients1. We, therefore, aimed to determine if NHF use for COVID-19 patients was associated with higher environmental surface SARS-CoV-2 contamination compared with those who were f intubated and mechanically ventilated (MV). oo We performed an observational, single-centre study initially including 10 consecutive critically r ill COVID-19 patients who required ICU admission (5 NHF and 5 MV). All patients were -p admitted to ICU negative pressure single rooms with 12 air changes per hour. Closed-aspiration re systems were used in mechanically ventilated patients. Patients with NHF only wore surgical lP masks above the NHF cannula when healthcare personnel were inside the room. The Ethics na Committee of Vall d’Hebron University Hospital approved this study (PR(AG)225/2020), and ur the need for informed consent was waived due to the observational nature of the study. Jo Confirmation of SARS-CoV-2 persistence on environmental surfaces was based on the detection of viral genome by reverse-transcription quantitative polymerase chain reaction (RT- qPCR). Sample collection was performed within the first 24 hours of admission and after 3 days, before the daily room cleaning, from the following sites: bedside monitor, mechanical ventilator screen, computer keyboard, nurse medication trolley, infusion pumps, patient sheet, bed handle, personnel protective equipment (gloves, coat, protection glasses, hat), stethoscope, room floor at 1.5 metres distance from the patient, and a filter paper placed immediately before the room high efficiency particulate air (HEPA) filter. Environmental and equipment surfaces (approximately 5x5 cm) were sampled using moistened sterile swabs. 1 If all samples were negative, inclusion of two additional patients (one of each group [NHF and MV]) was planned. Two more samples were collected for these two additional patients. First, air sampling of room air was performed using a Sartorius MD8 microbiological sampler, containing a gelatine membrane filter for a fixed given sample volume of 1000l by placing the sampler near the patient (50 cm). After sampling, the filter was immediately sent to the lab where 3 ml of Dulbecco’s modified Eagle medium (DMEM; Lonza, Allendale, NJ) was added and frozen at -80 ºC until the analysis was performed. A second additional sample from the NHF cannula of the non-intubated patient was also obtained. The swabs were transferred f oo immediately into 3 ml of DMEM, sent out to the microbiology laboratory and frozen at -80ºC r until RT-qPCR analyses were done. Total nucleic acids were extracted using NucliSENS -p EasyMAG (BioMérieux, Marcy l’Etoile, France) according to the manufacturer’s instructions. re Detection of SARS-CoV-2 genome was carried out by a commercial multiplex RT-qPCR assay lP (TaqMan™ 2019-nCoV Assay Kit v2, Thermofisher, USA). na SARS-CoV-2 samples containing viral RNA, as determined by RT-qPCR, were assessed for the presence of infectious virus by titration in Vero E6 cells (ATCC® CRL384 1586™), as ur previously reported 2, 3. Vero E6 cells were cultured in DMEM (Lonza) supplemented with 2% Jo foetal calf serum (FCS; EuroClone), 100 U/mL penicillin (ThermoFisher Scientific, Life Technologies), 100 μg/ml streptomycin (ThermoFisher Scientific, Life Technologies), and 2 mM glutamine (ThermoFisher Scientific, Life Technologies). Direct samples and serial ten-fold dilutions in supplemented DMEM were transferred to Vero E6 monolayers. Plates were monitored daily under a light microscope and wells were evaluated for the presence of cytopathic effect (CPE) at 6 days after infection. Results are expressed as median (25th percentile–75th percentile). The main characteristics of the patients included in this study are summarized in Table 1. Two of the patients were initially included as MV patients (only have samples at day 1 of MV) and 2 subsequent samples were collected when they were supported with NHF after extubation (cases 1 and 2 among MV patients that correspond to cases 6 and 8 among NHF patients, respectively). A total of 252 environmental samples were collected from the first 10 patients. No differences between the time of positive nasopharyngeal swab collection and time of environmental sample collection were observed (median of 3 days [1-5] in NHF and 4 [3-9] in MV patients; p= 0.222). At the time of first collection, patients with NHF were supported with a median flow of 55 Lpm (50-60) and had a median respiratory rate of 23 (22-24) bpm and a SpO2/FIO2 ratio of 154 (145-192). The RT-qPCR reactions were negative for all the tested f oo surfaces. r An additional 29 samples were obtained from two more patients. Only the sample collected -p from the NHF cannula was positive for SARS-CoV-2 RNA. This NHF cannula positive sample re was inoculated to susceptible Vero E6 cells, but no CPE was observed after a 6-day observation lP period. Therefore, no infectious SARS-CoV-2 was found in any of the environmental samples na collected in this study. However, the degree of surface and air contamination from SARS-CoV- 2 in a previous study was highly heterogeneous4. The singularity of the present study is that it ur includes the largest data on the environmental persistence of SARS-CoV-2 in the rooms of Jo COVID-19 patients being treated with NHF. Moreover, we compared the environmental contamination associated with NHF use to MV. Lack of environmental contamination in an ICU environment with negative pressure rooms was observed in both groups. Indeed, it has recently been shown that NHF by itself may not increase aerosol generation in healthy volunteers in a negative-pressure room 5. Interestingly, despite it being impossible to place living SARS-CoV-2 on a surface to obtain a positive control for obvious safety reasons, we could obtain one positive RT-qPCR from the nasal cannula of one of the non-intubated patients suggesting that the sample collection and PCR technique was correctly performed. These 3 results were similar to the previous reported by Colaneri et al6 that obtained a unique positive PCR sample from inside the helmet of one non-intubated patient. However, The limitations of this study are that, first, air sampling was performed in only two patients and we cannot exclude that with increasing the litres of air sampling, we could likely obtain a positive sample. Secondly, the study was performed in ICU rooms with negative pressure and use of closed-aspiration systems in intubated patients and therefore its results may not be generalizable to other hospital environments. Despite these limitations, our results suggest that, with adequate infrastructure, NHF does not f oo increase environmental surface contamination in critically ill patients with COVID-19. r -p re Authors’ Contributions: lP OR, VRG, JVA contributed to the conception and design of the study, the acquisition, analysis na and interpretation of the data and drafting the manuscript. AP, JR, contributed to the acquisition, analysis and interpretation of the data and drafting the manuscript. AA, LA, MC, ur JS, TP, RF, contributed to the conception and design of the study and interpretation of the data. Jo All authors critically revised and approved the final version of the manuscript. Conflicts of interest: OR reports speaker fees from Hamilton Medical, Ambu and Aerogen Ltd and research grant by Hamilton Medical. He also received non-financial research support from Timpel and Masimo Corporation in the last five years all outside the submitted work. Funding: 4 This study has been funded by a grant of Instituto de Salud Carlos III of the Spanish Health Ministry (COV20-01054). f r oo -p re lP na ur Jo 5 References 1. Raoof S, Nava S, Carpati C, Hill NS High-Flow, Noninvasive Ventilation and Awake (Nonintubation) Proning in Patients With Coronavirus Disease 2019 With Respiratory Failure. Chest 2020; 158: 1992-2002. 2. Rodon J, Muñoz-Basagoiti J, Perez-Zsolt D et al. Identification of Plitidepsin as Potent Inhibitor of SARS-CoV-2-Induced Cytopathic Effect after a Drug Repurposing Screen. 2021; doi https://doi.org/10.1101/2020.04.23.055756. 3. Brustolin M, Rodon J, Rodríguez de la Concepción M et al. Protection against reinfection with D614- or G614-SARS-CoV-2 isolates in hamsters. 2021; doi https://doi.org/10.1101/2021.01.07.425729. 4. Birgand G, Peiffer-Smadja N, Fournier S, Kerneis S, Lescure FX, Lucet JC Assessment of Air Contamination by SARS-CoV-2 in Hospital Settings. JAMA Netw Open 2020; 3: e2033232. 5. Gaeckle NT, Lee J, Park Y, Kreykes G, Evans MD, Hogan CJ, Jr. Aerosol Generation from the Respiratory Tract with Various Modes of Oxygen Delivery. Am J Respir Crit Care Med 2020; f 202: 1115-24. oo 6. Colaneri M, Seminari E, Novati S et al. Severe acute respiratory syndrome coronavirus 2 RNA contamination of inanimate surfaces and virus viability in a health care emergency unit. Clinical microbiology and infection : the official publication of the European Society of Clinical r Microbiology and Infectious Diseases 2020; 26: 1094.e1-.e5. -p re lP na ur Jo 6 Table 1. General characteristics of the population included Nº of Type of Days from positive quadrants in D-dimer IL-6 Case Age SAPS III APACHE II Type of room respiratory RT-qPCR to first Chest-X- (ng/ml) (mg/dL) support sample collection Ray ICU single-room with 1 37 23 19 4 171 100 MV 3 negative pressure ICU single-room with of 2 56 49 18 2 6329 2359 MV 3 negative pressure ro ICU single-room with 3 49 13 22 4 221 195 MV 9 negative pressure -p ICU single-room with 4 55 30 22 4 3177 53 MV 3 re negative pressure ICU single-room with lP 5 71 67 31 4 953 103 MV 10 negative pressure ICU single-room with na 6 37 23 20 4 171 100 NHF 1 negative pressure ur ICU single-room with 7 44 32 21 2 225 108 NHF 6 negative pressure Jo ICU single-room with 8 56 49 18 2 6329 2359 NHF 5 negative pressure ICU single-room with 9 54 25 22 4 1321 4541 NHF 4 negative pressure ICU single-room with 10 69 30 31 4 456 365 NHF 1 negative pressure Intermediate care, 11 72 23 26 2 170 22 NHF 1 double-room ICU single-room with 12 39 38 19 4 3319 2656 MV 5 negative pressure SAPS III: Simplified Acute Physiology Score; APACHE II: Acute Physiology and Chronic Health disease Classification System; IL: interleukin; MV: mechanical ventilation; NHF: nasal high flow; RT-qPCR: real-time reverse-transcription polymerase chain reaction. of ro -p re lP na ur Jo