الفهرس 
Acute Respiratory FailureOnly 14 pages are availabe for public view
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Abstract
NIV use can be limited due to patient intolerance of the interface or positive pressure. NIV requires a tight-fitting mask or helmet, delivery of high pressures to an a wake patient, is associated with skin injuries after prolonged use, causes gastric insufflation with increased risk of aspiration, can be associated with patient-ventilator asynchrony, and limits both secretion management and nutritional intake.Patients who cannot tolerate NIV will often require invasive mechanical ventilation, however official ERS/ATS guidelines recommend NIV for COPD patients with acute hypercapnic acidotic respiratory failure (pH ≤7.35)\ (108). While HFNC is more reasonable and comfortable in comparison to COT and to NIV, its capability to reduce work of breathing in ARF may be less than that provided by NIV(123) . Physiological studies suggest that the high gas flows of HFNC may improve ventilation by increasing mean airway pressure and washout of dead space, all while being more comfortable and tolerable by the patient (124). Whereas HVNI delivers similar quantities of oxygen at flow rates up to 40 L/min due to increased velocity derived from a lower flow with a higher level of kinetic energy in the delivered gas. It utilizes a smaller bore nasal cannula which close about 50% of the surface area of the nostrils to generate higher velocities of gas delivery than its counterparts using large bore HFNC, has the ability to accomplish complete purge of extrathoracic dead space at flow rates of 35 liters/min and may be able to provide ventilatory support in patients with acute hypercapnic respiratory failure in addition to oxygenation support (119). The Aim of the study was to compare the effectiveness, risks and benefits of HFNC/HVNI versus NIV in patients with acute hypoxemic or hypercapnic respiratory failure.
This was a prospective comparative study that was conducted in Chest Department Menoufia university hospital and Kafr El Sheikh Chest hospital on 60 patients with ARF from April 2021 to March 2022 who were classified into two equal groups. group A: Included 30 patients with ARF who were placed on HVNI (group A1) HFNC (group A2). group B: Included 30 patients with ARF who were placed on NIV. Each group was subdivided into two subgroups: 15 Pateints of ARF due to COVID 19 virus. 15 Patients of ARF due to non-COVID 19 virus. All patients were subjected to full history taking ,clinical examination, laporatory investigation and radiological assessment. group A was placed on(HVNI- HFNC) using firstly, group A1 were placed on a Precision Flow® Hi-VNI Packaging (Vapotherm Inc., USA) as HVNI device which delivered air flows stated from 10 up to 40 L/min to rise the O2 saturation above 92%(that made PEEP from 1.7 to 5) and humidification chamber was set at 37°C and diminished in case of discomfort.
group A2 were placed on I Breathe HF60 TM - Bio Business as HFNC device which delivered air flows stated from 10 up to 50 and 60 L/m to rise the O2 saturation above 92% (that made PEEP from 1.7 to 7.7) and humidification chamber was set at 37°C and diminished in case of discomfort.
They were followed up for improvement and treatment failure through monitoring ABGs, ROX index which is the ratio of SpO2/FiO2 to respiratory rate (RR) after 12 hours of initiation of treatment.
group B were placed on NIV, (Machine Model Vivo 2 and Dräger Evita® Infinity® V500 ventilator), The initial IPAP was set at 10 cmH2O and increased to at least 15 cmH2O if PH was less than 7.25, and the EPAP was set at the lowest setting available in the used machine at 4 cmH2O, that help to avoid CO2 rebreathing through exhalation port and may be increased to maximum level of 7 cmH2O in COPD depending on PaCO2. Supplemental oxygen was given through a mask to keep oxygen saturation above or equal to 90%. During the first trial, IPAP was increased by 1 cmH2O / 30 min or higher according to the patient tolerance, while in CPAP mode the pressure was set at 10 cmH2O and increased to at least 15 if SaO2 was still below 92%.