Comparison of SpO 2/FiO 2 and ROX index for predicting failure of high-flow nasal cannula therapy in children with acute respiratory failure after congenital heart surgery / 中国小儿急救医学

Objective:To compare the predictive ability of SpO 2/FiO 2(S/F) and ROX index on the failure of high-flow nasal cannula(HFNC)therapy in children with acute respiratory failure after congenital heart disease surgery, and to identify the best cut-off point. Methods:Through a case-control study, the clinical data of 371 children with acute respiratory failure after congenital heart surgery treated with HFNC admitted to Guangzhou Women and Children′s Medical Center from January 2018 to December 2021 were retrospectively analyzed.The primary outcome was the need for re-intubation within 48 h after extubation of invasive ventilation.The ability of S/F and ROX index to predict HFNC failure was compared, and the optimal cut-off point was determined based on the area under the curve (AUC) of receiver operating characteristic curve.Results:A total of 371 children were included, of whom 27 (7.3%) eventually required mechanical ventilation within 48 h. The S/F prediction accuracy was highest after 6 h of HFNC treatment(AUC=0.712, 95% CI 0.599-0.825, P=0.001), and the best cut-off point for S/F was 178 mmHg(1 mmHg=0.133 kPa)(sensitivity 74.9%, specificity 69.6%). Whereas the prediction accuracy of the ROX index was highest after 12 hours of HFNC treatment, the AUC was 0.737(95% CI 0.623-0.851, P=0.002), and the best cut-off point of the ROX index was 5.865(sensitivity 72.4% specificity 66.7%). The difference in AUC between S/F after 6 h of HFNC treatment and ROX after 12 h was not statistically significant ( P=0.444), with higher sensitivity and specificity, and earlier prediction time(6 hours) in the former. Conclusion:Children with acute respiratory failure after congenital heart surgery have a strong predictive ability of S/F after 6 h of HFNC treatment, and the risk of HFNC treatment failure is higher in children with S/F <178 mmHg.

[Operating principles, physiological effects and practical issues of high-flow nasal oxygen therapy]. / Principes de fonctionnement, effets physiologiques et aspects pratiques de l'oxygénothérapie à haut débit.

First-line symptomatic treatment of acute respiratory failure (ARF) usually requires standard oxygen therapy, of which the limits have nonetheless led to the development of heated and humidified high-flow nasal oxygen therapy (HFNO). HFNO enables the delivery, through simple nasal cannula, of up to 100% of well-heated and humidified fraction of inspired oxygen (FiO2), at a maximum flow rate of 50 to 70 L/min of gas according to the devices chosen (specific or ventilator). The technical characteristics and operating principles of HFNO (coverage of the patient's spontaneous inspiratory flow, improved conditioning of the inspired gases, comfortable nasal cannula) yield a number of interdependent physiological effects that improve not only oxygenation conditions but also ventilatory mechanics. While it could be indicated in many clinical situations, including first-line hypoxemic ARF, the simplicity of HFNO implementation and the respiratory comfort it procures should in no way minimize the clinical monitoring of patients for whom endotracheal intubation may be required, and should not be unduly delayed.

Use of Humidified High Flow Nasal Oxygen in Community Palliative Care: A Case Report.

Breathlessness is a distressing symptom that is often seen in palliative care patients with respiratory failure and it can make care in the home setting difficult. Humidified High Flow Nasal Oxygen is a relatively new intervention for respiratory failure, but it has not been researched greatly in a palliative care setting. One device with the capacity to deliver high flow humidified oxygen to spontaneously breathing patients is the myAIRVO2 humidifier.1 The myAIRVO2 is a humidifier with an integrated flow generator that delivers warmed and humidified respiratory gases to a spontaneously breathing patient.1 The following case report describes how the technology was used at home for symptom control in a 76 year old patient with severe chronic obstructive pulmonary disease with associated pulmonary hypertension. The patient was successfully discharged from hospital and managed at home using high-flow nasal oxygen for approximately one month up until his death. In this last month of life, he reported that he was more comfortable on high-flow nasal oxygen than on traditionally-administered oxygen. Humidified High Flow Nasal Oxygen is potentially beneficial to aid in symptom control for palliative care patients in an inpatient and community setting.

Use of transnasal humidified rapid-insufflation ventilatory exchange (THRIVE) to facilitate the management of subglottic stenosis in pregnancy.

Subglottic stenosis is a rare condition. Diagnosis is often delayed as symptoms are attributed to other causes, such as asthma. This problem may be compounded in pregnancy when dyspnoea may be attributed to normal physiological changes. In respiratory compromise, surgical intervention may be required and airway management is challenging as endotracheal intubation may be traumatic or, in severe cases, impossible. Transnasal humidified rapid-insufflation ventilatory exchange (THRIVE) is a novel open-airway apnoeic technique using high-flow nasal oxygen. It does not expose the patient to the risks of jet ventilation, nor does it require the placement of an airway device to effectively oxygenate the patient. In pregnancy, elevation of maternal carbon dioxide is of particular concern as it may result in a worsening fetal acidosis. While THRIVE has been shown to provide some clearance of carbon dioxide, a patent airway is required for it to function effectively. In this case report we describe the management of a pregnant patient who underwent balloon dilatation for severe subglottic stenosis at 23 weeks' gestation using THRIVE and we summarise the evidence supporting the use of this new technique in pregnant women.

Randomized Controlled Trial of Humidified High-Flow Nasal Oxygen for Acute Respiratory Distress in the Emergency Department: The HOT-ER Study.

BACKGROUND: Humidified high-flow nasal cannula (HFNC) is a novel method of oxygen delivery with increasing use in emergency departments and intensive care settings despite little evidence showing benefit over standard oxygen delivery methods (standard O2). The aim of this study was to determine whether HFNC compared with standard O2 given to subjects in acute respiratory distress would reduce the need for noninvasive ventilation or invasive ventilation. METHODS: This was a pragmatic open randomized controlled trial in adult subjects with hypoxia and tachypnea presenting to a tertiary academic hospital emergency department. The primary outcome was the need for mechanical ventilation in the emergency department. RESULTS: We screened 1,287 patients, 322 met entry criteria and 19 were excluded from analysis. Of these, 165 randomized to HFNC and 138 to standard O2 were analyzed. Baseline characteristics were similar. In the HFNC group, 3.6% (95% CI 1.5-7.9%) versus 7.2% (95% CI 3.8-13%) in the standard O2 group required mechanical ventilation in the emergency department (P = .16), and 5.5% (95% CI 2.8-10.2%) in HFNC versus 11.6% (95% CI 7.2-18.1%) in the standard O2 group required mechanical ventilation within 24 h of admission (P = .053). There was no difference in mortality or stay. Adverse effects were infrequent; however, fewer subjects in the HFNC group had a fall in Glasgow coma score due to CO2 retention, 0% (95% CI 0-3%) versus 2.2% (95% CI 0.4-6%). One in 12 subjects did not tolerate HFNC. CONCLUSIONS: HFNC was not shown to reduce the need for mechanical ventilation in the emergency department for subjects with acute respiratory distress compared with standard O2, although it was safe and may reduce the need for escalation of oxygen therapy within the first 24 h of admission.

[High flow, humidified-reheated oxygen therapy: a new oxygenation technique for adults]. / L'oxygénothérapie humidifiée-réchauffée à haut débit : une nouvelle technique d'oxygénation chez l'adulte.

Currently conventional oxygen therapy is the first choice symptomatic treatment in the management of acute respiratory failure (ARF). However, conventional oxygen therapy has important limitations which have lead to the development of heated and humidified high-flow nasal oxygen therapy (HFNO). HFNO is an innovative technique that can deliver, through special nasal cannulae, up to 100% of the inspired fraction (FiO2) with heated and humidified oxygen at a maximum flow of 70L/min. The characteristics of this technique (overcoming the patient's spontaneous inspiratory flow, heated humidification,) and its physiological effects (no dilution of FiO2, positive end-expiratory pressure, pharyngeal dead-space washout, decrease in airway resistance), allow efficient optimization of oxygenation with better tolerance for patients. Current data, mainly observational, show that HFNO could be used particularly for the management of hypoxemic ARF, notably in the more severe forms. Indications for using HFNO, alone or in association with noninvasive ventilation, are potentially very broad and may involve different types of ARF (post-operative, post-extubation, palliative care) and even the practice of invasive technical procedures (bronchial fibroscopy). However, though current studies are very encouraging and promise a clinical benefit on patient outcomes, randomized trials are still needed to demonstrate that HFNO avoids the need for endotracheal intubation in the management of ARF.