High-flow nasal cannula oxygen versus non-invasive ventilation in patients with acute hypoxaemic respiratory failure undergoing flexible bronchoscopy - a prospective randomised trial

Introduction

Critically ill patients with respiratory failure undergoing bronchoscopy have an increased risk of hypoxaemia-related complications. Previous studies have shown that in awake, hypoxaemic patients non-invasive ventilation (NIV) is helpful in preventing gas exchange deterioration during bronchoscopy. An alternative and increasingly used means of oxygen delivery is its application via high-flow nasal cannula (HFNC). This study was conducted to compare HFNC with NIV in patients with acute hypoxaemic respiratory failure undergoing flexible bronchoscopy.

Methods

Prospective randomised trial randomising 40 critically ill patients with hypoxaemic respiratory failure to receive either NIV or HFNC during bronchoscopy in the intensive care unit.

Results

After the initiation of NIV and HFNC, oxygen levels were significantly higher in the NIV group compared to the HFNC group. Two patients were unable to proceed to bronchoscopy after the institution of HFNC due to progressive hypoxaemia. During bronchoscopy, one patient on HFNC deteriorated due to intravenous sedation requiring non-invasive ventilatory support. Bronchoscopy was well tolerated in all other patients. There were no significant differences between the two groups regarding heart rate, mean arterial pressure and respiratory rate. Three patients in the NIV group and one patient in the HFNC group were intubated within 24 hours after the end of bronchoscopy (P = 0.29).

Conclusions

The application of NIV was superior to HFNC with regard to oxygenation before, during and after bronchoscopy in patients with moderate to severe hypoxaemia. In patients with stable oxygenation under HFNC, subsequent bronchoscopy was well tolerated.

Trial registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT01870765","term_id":"NCT01870765"}}NCT01870765. Registered 30 May 2013.     

High-flow nasal cannula (HFNC) support in interhospital transport of critically ill children

Purpose

Optimal respiratory support for interhospital transport of critically ill children is challenging and has been scarcely investigated. High-flow nasal cannula (HFNC) therapy has emerged as a promising support mode in the paediatric intensive care unit (PICU), but no data are available on HFNC used during interhospital transport. We aimed to assess the safety of HFNC during retrievals of critically ill children and its impact on the need for invasive ventilation (IV).

Methods

This was a retrospective, single-centre study of children under 2 years old transported by a specialized paediatric retrieval team to PICU. We compared IV rates before (2005–2008) and after introduction of HFNC therapy (2009–2012).

Results

A total of 793 infants were transported. The mean transport duration was 1.4 h (range 0.25–8), with a mean distance of 205 km (2–2,856). Before introduction of HFNC, 7 % (n = 23) were retrieved on non-invasive ventilation (NIV) and 49 % (n = 163) on IV. After introduction of HFNC, 33 % (n = 150) were retrieved on HFNC, 2 % (n = 10) on NIV, whereas IV decreased to 35 % (n = 162, p < 0.001). No patients retrieved on HFNC required intubation during retrieval, or developed pneumothorax or cardiac arrest. Using HFNC was associated with a significant reduction in IV initiated by the retrieval team (multivariate OR 0.51; 95 % CI 0.27–0.95; p = 0.032).

Conclusions

We report on a major change of practice in transport of critically ill children in our retrieval system. HFNC therapy was increasingly used and was not inferior to low-flow oxygen or NIV. Randomized trials are needed to assess whether HFNC can reduce the need for IV in interhospital transport of critically ill children.     

High flow nasal cannula (HFNC) versus nasal continuous positive airway pressure (nCPAP) for the initial respiratory management of acute viral bronchiolitis in young infants: a multicenter randomized controlled trial (TRAMONTANE study)

Purpose

Nasal continuous positive airway pressure (nCPAP) is currently the gold standard for respiratory support for moderate to severe acute viral bronchiolitis (AVB). Although oxygen delivery via high flow nasal cannula (HFNC) is increasingly used, evidence of its efficacy and safety is lacking in infants.

Methods

A randomized controlled trial was performed in five pediatric intensive care units (PICUs) to compare 7 cmH₂O nCPAP with 2 L/kg/min oxygen therapy administered with HFNC in infants up to 6 months old with moderate to severe AVB. The primary endpoint was the percentage of failure within 24 h of randomization using prespecified criteria. To satisfy noninferiority, the failure rate of HFNC had to lie within 15% of the failure rate of nCPAP. Secondary outcomes included success rate after crossover, intubation rate, length of stay, and serious adverse events.

Results

From November 2014 to March 2015, 142 infants were included and equally distributed into groups. The risk difference of ?19% (95% CI ?35 to ?3%) did not allow the conclusion of HFNC noninferiority (p = 0.707). Superiority analysis suggested a relative risk of success 1.63 (95% CI 1.02–2.63) higher with nCPAP. The success rate with the alternative respiratory support, intubation rate, durations of noninvasive and invasive ventilation, skin lesions, and length of PICU stay were comparable between groups. No patient had air leak syndrome or died.

Conclusion

In young infants with moderate to severe AVB, initial management with HFNC did not have a failure rate similar to that of nCPAP. This clinical trial was recorded in the National Library of Medicine registry (NCT 02457013).

     

Is treatment with a high flow nasal cannula effective in acute viral bronchiolitis? A physiologic study

Purpose

The high flow nasal cannula (HFNC) has recently been proposed to support infants with respiratory syncytial virus (RSV)-related respiratory distress. However, in this disease, no physiologic data are currently available on the effects of this device. We assessed the capacity of HFNC to generate positive airway pressure, as well as the resulting effects on breathing pattern and respiratory effort.

Methods

Twenty-one infants less than 6 months old with acute RSV bronchiolitis were studied prospectively in the pediatric intensive care unit of a university hospital. Pharyngeal pressure (PP) and esophageal pressure (Pes) were measured simultaneously at four increasing flows of 1, 4, 6 and 7 L/min delivered through HFNC.

Results

The PP was correlated with flow rate (r = 0.65, p ≤ 0.0001), reaching mean and end-expiratory values of, respectively, 4 (95% CI 3–5) cmH₂O and 6.5 (95% CI 5–8) cmH₂O at 7 L/min. A flow ≥2 L/kg/min was associated with the generation of a mean pharyngeal pressure ≥4 cmH₂O with a sensitivity of 67 %, a specificity of 96 %, a positive predictive value of 75 %, and a negative predictive value of 94.5%. Only flows ≥6 L/min provided positive PP throughout the respiratory cycle. From baseline to maximal flow rate, breathing frequency (p < 0.01), T _i/T _tot (p < 0.05), Pes swing (p < 0.05) and PTPes_insp/min (p < 0.01), an index of respiratory effort, were reduced.

Conclusions

HFNC with a flow rate equal to or above 2 L/kg/min generated a clinically relevant PP, with improved breathing pattern and rapid unloading of respiratory muscles, in young infants with acute RSV bronchiolitis.     

Effects of reduced rebreathing time, in spontaneously breathing patients, on respiratory effort and accuracy in cardiac output measurement when using a partial carbon dioxide rebreathing technique: a prospective observational study

Introduction

New technology using partial carbon dioxide rebreathing has been developed to measure cardiac output. Because rebreathing increases respiratory effort, we investigated whether a newly developed system with 35 s rebreathing causes a lesser increase in respiratory effort under partial ventilatory support than does the conventional system with 50 s rebreathing. We also investigated whether the shorter rebreathing period affects the accuracy of cardiac output measurement.

Method

Once a total of 13 consecutive post-cardiac-surgery patients had recovered spontaneous breathing under pressure support ventilation, we applied a partial carbon dioxide rebreathing technique with rebreathing of 35 s and 50 s in a random order. We measured minute ventilation, and arterial and mixed venous carbon dioxide tension at the end of the normal breathing period and at the end of the rebreathing periods. We then measured cardiac output using the partial carbon dioxide rebreathing technique with the two rebreathing periods and using thermodilution.

Results

With both rebreathing systems, minute ventilation increased during rebreathing, as did arterial and mixed venous carbon dioxide tensions. The increases in minute ventilation and arterial carbon dioxide tension were less with 35 s rebreathing than with 50 s rebreathing. The cardiac output measures with both systems correlated acceptably with values obtained with thermodilution.

Conclusion

When patients breathe spontaneously the partial carbon dioxide rebreathing technique increases minute ventilation and arterial carbon dioxide tension, but the effect is less with a shorter rebreathing period. The 35 s rebreathing period yielded cardiac output measurements similar in accuracy to those with 50 s rebreathing.     

Beat-to-beat changes in stroke volume precede the general circulatory effects of mechanical ventilation: a case report

Background

The haemodynamic as well as the ventilatory consequences of mechanical ventilation can be harmful in critically ill neonates. Newly developed ventilatory lung protective strategies are not always available immediately and in an acute situation the haemodynamic changes caused by mechanical ventilation can affect the oxygen delivery considerably. We report the case of a male neonate who was treated with conventional pressure-controlled mechanical ventilation because of respiratory distress and progressive respiratory acidosis resulting from meconium aspiration. Because of poor arterial oxygenation despite 100% inspired oxygen and increased ventilator settings, echocardiography was performed to exclude central haemodynamic reasons for low oxygen delivery.

Method

Doppler echocardiography was used for the measurement of stroke volume and cardiac output. Pulse oximetry and aortic blood pressure were monitored continuously.

Results

Echocardiography revealed no cardiac malformations or signs of persistent fetal circulation. When inspiratory pressures and duration were increased, beat-to-beat variation in stroke volume preceded decay in cardiac output. Stroke volume variations and oxygen saturation values guided ventilator settings until extracorporal membrane oxygenation could be arranged for. After recovery and discharge 4 weeks later the boy is progressing normally.

Conclusion

Because oxygen delivery is dependent on both blood flow and arterial oxygen content, measurement of cardiac output as well as left heart oxygen saturation is a useful guide to optimizing oxygen delivery. This case report demonstrates how Doppler echocardiographic monitoring of beat-to-beat changes in stroke volume can be used to detect early negative haemodynamic effects of increased mechanical ventilation settings before cardiac output is affected.     

Noninvasive ventilation in chest trauma: systematic review and meta-analysis

Purpose

Single studies of Noninvasive Ventilation (NIV) in the management of acute respiratory failure in chest trauma patients have produced controversial findings. The aim of this study is to critically review the literature to investigate whether NIV reduces mortality, intubation rate, length of stay and complications in patients with chest trauma, compared to standard therapy.

Methods

We performed a systematic review and meta-analysis of randomized controlled trials, prospective and retrospective observational studies, by searching PubMed, EMBASE and bibliographies of articles retrieved. We screened for relevance studies that enrolled adults with chest trauma who developed mild to severe acute respiratory failure and were treated with NIV. We included studies reporting at least one clinical outcome of interest to perform a meta-analysis.

Results

Ten studies (368 patients) met the inclusion criteria and were included for the meta-analysis. Five studies (219 patients) reported mortality and results were quite homogeneous across studies, with a summary relative risk for patients treated with NIV compared with standard care (oxygen therapy and invasive mechanical ventilation) of 0.26 (95 % confidence interval 0.09–0.71, p = 0.003). There was no advantage in mortality of continuous positive airway pressure over noninvasive pressure support ventilation. NIV significantly increased arterial oxygenation and was associated with a significant reduction in intubation rate, in the incidence of overall complications and infections.

Conclusions

These results suggest that NIV could be useful in the management of acute respiratory failure due to chest trauma.     

Safety of performing fiberoptic bronchoscopy in critically ill hypoxemic patients with acute respiratory failure

Background

The safety of fiberoptic bronchoscopy (FOB) in nonintubated critically ill patients with acute respiratory failure has not been extensively evaluated. We aimed to measure the incidence of intubation and the need to increase ventilatory support following FOB and to identify predictive factors for this event.

Methods

A prospective multicenter observational study was carried out in eight French adult intensive care units. The study included 169 FOB performed in patients with a PaO₂/FiO₂ ratio ??300. The main end-point was intubation rate. The secondary end-point was rate of increased ventilatory support defined as an increase in oxygen requirement >50?%, the need to start noninvasive positive pressure ventilation (NI-PPV) or increase NI-PPV support.

Results

Within 24?h, an increase in ventilatory support was required following 59 bronchoscopies (35?%), of which 25 (15?%) led to endotracheal intubation. The existence of chronic obstructive pulmonary disease (COPD; OR 5.2, 95?% CI 1.6?C17.8; p?=?0.007) or immunosuppression (OR 5.4, 95?% CI 1.7?C17.2; p?=?0.004] were significantly associated with the need for intubation in the multivariable analysis. None of the baseline physiological parameters including the PaO₂/FiO₂ ratio was associated with intubation.

Conclusions

Bronchoscopy is often followed by an increase in ventilatory support in hypoxemic critically ill patients, but less frequently by the need for intubation. COPD and immunosuppression are associated with the need for invasive ventilation in the 24?h following bronchoscopy.     

Airway pressure release ventilation versus assist-control ventilation: a comparative propensity score and international cohort study

Purpose

To compare characteristics and clinical outcomes of patients receiving airway pressure release ventilation (APRV) or biphasic positive airway pressure (BIPAP) to assist-control ventilation (A/C) as their primary mode of ventilatory support. The objective was to estimate if patients ventilated with APRV/BIPAP have a lower mortality.

Methods

Secondary analysis of an observational study in 349 intensive care units from 23 countries. A total of 234 patients were included who were ventilated only with APRV/BIPAP and 1,228 patients who were ventilated only with A/C. A case-matched analysis according to a propensity score was used to make comparisons between groups.

Results

In logistic regression analysis, the most important factor associated with the use of APRV/BIPAP was the country (196 of 234 patients were from German units). Patients with coma or congestive heart failure as the reason to start mechanical ventilation, pH <7.15 prior to mechanical ventilation, and patients who developed respiratory failure (SOFA score >2) after intubation with or without criteria of acute respiratory distress syndrome were less likely to be ventilated with APRV/BIPAP. In the case-matched analysis there were no differences in outcomes, including mortality in the intensive care unit, days of mechanical ventilation or weaning, rate of reintubation, length of stay in the intensive care unit or hospital, and mortality in the hospital.

Conclusions

In this study, the APRV/BIPAP ventilation mode is being used widely across many causes of respiratory failure, but only in selected geographic areas. In our patient population we could not demonstrate any improvement in outcomes with APRV/BIPAP compared with assist-control ventilation.     

Increase in use of non-invasive ventilation for infants with severe bronchiolitis is associated with decline in intubation rates over a decade

Purpose

To redress the paucity of studies evaluating non-invasive respiratory support in bronchiolitis patients.

Methods

Following ethics committee approval, the clinical database of a tertiary 23-bed paediatric intensive care unit (PICU) was reviewed for bronchiolitis admissions from January 2000 to December 2009. Length of stay (LOS), ventilatory requirements and risk factors, including prematurity, respiratory syncytial virus (RSV) status, chronic lung, neuromuscular, immune and congenital heart disease, were analysed.

Results

Of 8,288 admissions, 520 (6.27?%) had bronchiolitis with 343 (65.9?%) having RSV. Median (±SD) age and LOS were 2.78?months and 2.68 (±4.32)?days. One (0.2?%) patient died. Assisted ventilation was required for 399 (76.7?%) patients. A total of 114 (28.6?%) patients were intubated directly and 285 (71.4?%) had a trial of non-invasive ventilation (NIV). Significant increase in the use of NIV was seen (2.8?%/year) with decline in intubation rates (1.9?%/ year) (p?=?0.002). Of NIV patients, 237 (83.2?%) needed only NIV and 48 (16.8?%) failed and therefore needed intubation. The median LOS was shorter in those who succeeded NIV (2.38?±?2.43?days) compared to those with invasive ventilation (5.19?±?6.34?days) and those who failed NIV (8.41?±?3.44?days). Presence of a risk factor increased the chances of failing NIV from 6 to 10?%.

Conclusion

NIV was successful in the vast majority of patients, particularly in those without risk factors and halved the LOS in intensive care. Failure of NIV was associated with increased duration of invasive ventilation and PICU LOS. A prospective study comparing different techniques of NIV will be helpful in defining the risks of failure of NIV.     

Outcomes and predictors of failure of non-invasive ventilation in patients with community acquired pneumonia in the ED

Objective

We set out to describe the use and analyze the predictors of non-invasive ventilation failure in patients with community-acquired pneumonia who receive non-invasive ventilation as first line ventilatory therapy in the emergency department.

Non-invasive mechanical ventilation for diagnostic bronchoscopy using a new face mask: an observational feasibility study

Purpose

Bronchoscopy is an indispensable tool for invasive pulmonary evaluation with high diagnostic yield and low incidence of major complications. However, hypoxemia increases the risk of complications, in particular after bronchoalveolar lavage. Non-invasive positive pressure ventilation may prevent hypoxemia associated with bronchoalveolar lavage. The purpose of this study is to present a modified total face mask to aid bronchoscopy during non-invasive positive pressure ventilation.

Methods

A commercially available full face mask was modified to allow introduction of the bronchoscope without interfering with the ventilator circuit. Bronchoscopy with bronchoalveolar lavage was performed in 12 hypoxemic non-ICU patients during non-invasive positive pressure ventilation in the ICU.

Results

Patients had severely impaired oxygen uptake as indicated by PaO₂/FiO₂ ratio 192  ± 23 mmHg before bronchoscopy. Oxygenation improved after initiation of non-invasive positive pressure ventilation. In all patients the procedure could be completed without subsequent complications, although in one patient SpO₂ decreased until 86% during bronchoscopy. A microbiological diagnosis could be established in 8 of 12 patients with suspected for infection.

Conclusions

Our modified face mask for non-invasive positive pressure ventilation is a valuable tool to aid diagnostic bronchoscopy in hypoxemic patients.     

A multicenter randomized controlled trial of a 3-L/kg/min versus 2-L/kg/min high-flow nasal cannula flow rate in young infants with severe viral bronchiolitis (TRAMONTANE 2)

Purpose

High-flow nasal cannula (HFNC) therapy is increasingly proposed as first-line respiratory support for infants with acute viral bronchiolitis (AVB). Most teams use 2 L/kg/min, but no study compared different flow rates in this setting. We hypothesized that 3 L/kg/min would be more efficient for the initial management of these patients.

Methods

A randomized controlled trial was performed in 16 pediatric intensive care units (PICUs) to compare these two flow rates in infants up to 6 months old with moderate to severe AVB and treated with HFNC. The primary endpoint was the percentage of failure within 48 h of randomization, using prespecified criteria of worsening respiratory distress and discomfort.

Results

From November 2016 to March 2017, 142 infants were allocated to the 2-L/kg/min (2L) flow rate and 144 to the 3-L/kg/min (3L) flow rate. Failure rate was comparable between groups: 38.7% (2L) vs. 38.9% (3L; p?=?0.98). Worsening respiratory distress was the most common cause of failure in both groups: 49% (2L) vs. 39% (3L; p?=?0.45). In the 3L group, discomfort was more frequent (43% vs. 16%, p?=?0.002) and PICU stays were longer (6.4 vs. 5.3 days, p?=?0.048). The intubation rates [2.8% (2L) vs. 6.9% (3L), p?=?0.17] and durations of invasive [0.2 (2L) vs. 0.5 (3L) days, p?=?0.10] and noninvasive [1.4 (2L) vs. 1.6 (3L) days, p?=?0.97] ventilation were comparable. No patient had air leak syndrome or died.

Conclusion

In young infants with AVB supported with HFNC, 3 L/kg/min did not reduce the risk of failure compared with 2 L/kg/min. This clinical trial was recorded on the National Library of Medicine registry (NCT02824744).

     

Patient-ventilator asynchronies: may the respiratory mechanics play a role?

Introduction

The mechanisms leading to patient/ventilator asynchrony has never been systematically assessed. We studied the possible association between asynchrony and respiratory mechanics in patients ready to be enrolled for a home non-invasive ventilatory program. Secondarily, we looked for possible differences in the amount of asynchronies between obstructive and restrictive patients and a possible role of asynchrony in influencing the tolerance of non-invasive ventilation (NIV).

Methods

The respiratory pattern and mechanics of 69 consecutive patients with chronic respiratory failure were recorded during spontaneous breathing. After that patients underwent non-invasive ventilation for 60 minutes with a "dedicated" NIV platform in a pressure support mode during the day. In the last 15 minutes of this period, asynchrony events were detected and classified as ineffective effort (IE), double triggering (DT) and auto-triggering (AT).

Results

The overall number of asynchronies was not influenced by any variable of respiratory mechanics or by the underlying pathologies (that is, obstructive vs restrictive patients). There was a high prevalence of asynchrony events (58% of patients). IEs were the most frequent asynchronous events (45% of patients) and were associated with a higher level of pressure support. A high incidence of asynchrony events and IE were associated with a poor tolerance of NIV.

Conclusions

Our study suggests that in non-invasively ventilated patients for a chronic respiratory failure, the incidence of patient-ventilator asynchronies was relatively high, but did not correlate with any parameters of respiratory mechanics or underlying disease.     

Critically ill infants and children with influenza A (H1N1) in pediatric intensive care units in Argentina

Objective

To determine the epidemiological features, course, and outcomes of critically ill pediatric patients with Influenza A (H1N1) virus.

Design

Prospective cohort of children in pediatric intensive care units (PICUs) due to Influenza A (H1N1) virus infection.

Setting

Seventeen medical-surgical PICUs in tertiary care hospital in Argentina.

Patients

All consecutive patients admitted to the PICUs with influenza A (H1N1) viral infection from 15 June to 31 July 2009.

Measurements and main results

Of 437 patients with acute lower respiratory infection in PICUs, 147 (34%) were diagnosed with influenza A (H1N1) related to critical illness. The median age of these patients was 10 months (IQR 3–59). Invasive mechanical ventilation was used in 117 (84%) on admission. The rate of acute respiratory distress syndrome (ARDS) was 80% (118 of 147 patients). Initial non-invasive ventilation failed in 19 of 22 attempts (86%). Mortality at 28 days was 39% (n = 57). Chronic complex conditions (CCCs), acute renal dysfunction (ARD) and ratio PaO₂/FiO₂ at day 3 on MV were independently associated with a higher risk of mortality. The odds ratio (OR) for CCCs was 3.06, (CI 95% 1.36–6.84); OR for ARD, 3.38, (CI 95% 1.45–10.33); OR for PaO₂/FiO₂, 4 (CI 95% 1.57–9.59). The administration of oseltamivir within 24 h after admission had a protective effect: OR 0.2 (CI 95% 0.07–0.54).

Conclusions

In children with ARDS, H1N1 as an etiologic agent confers high mortality, and the presence of CCCs in such patients increases the risk of death.     

Associations between ventilator settings during extracorporeal membrane oxygenation for refractory hypoxemia and outcome in patients with acute respiratory distress syndrome: a pooled individual patient data analysis

Purpose

Extracorporeal membrane oxygenation (ECMO) is a rescue therapy for patients with acute respiratory distress syndrome (ARDS). The aim of this study was to evaluate associations between ventilatory settings during ECMO for refractory hypoxemia and outcome in ARDS patients.

Methods

In this individual patient data meta-analysis of observational studies in adult ARDS patients receiving ECMO for refractory hypoxemia, a time-dependent frailty model was used to determine which ventilator settings in the first 3 days of ECMO had an independent association with in-hospital mortality.

Results

Nine studies including 545 patients were included. Initiation of ECMO was accompanied by significant decreases in tidal volume size, positive end-expiratory pressure (PEEP), plateau pressure, and driving pressure (plateau pressure ? PEEP) levels, and respiratory rate and minute ventilation, and resulted in higher PaO₂/FiO₂, higher arterial pH and lower PaCO₂ levels. Higher age, male gender and lower body mass index were independently associated with mortality. Driving pressure was the only ventilatory parameter during ECMO that showed an independent association with in-hospital mortality [adjusted HR, 1.06 (95 % CI, 1.03–1.10)].

Conclusion

In this series of ARDS patients receiving ECMO for refractory hypoxemia, driving pressure during ECMO was the only ventilator setting that showed an independent association with in-hospital mortality.

     

Year in review 2013: <Emphasis Type="Italic">Critical Care</Emphasis>- respirology

This review documents important progress made in 2013 in the field of critical care respirology, in particular with regard to acute respiratory failure and acute respiratory distress syndrome. Twenty-five original articles published in the respirology and critical care sections of Critical Care are discussed in the following categories: pre-clinical studies, protective lung ventilation – how low can we go, non-invasive ventilation for respiratory failure, diagnosis and prognosis in acute respiratory distress syndrome and respiratory failure, and promising interventions for acute respiratory distress syndrome.     

Apnoeic oxygenation via high-flow nasal cannula oxygen combined with non-invasive ventilation preoxygenation for intubation in hypoxaemic patients in the intensive care unit: the single-centre,blinded, randomised controlled OPTINIV trial

Purpose

High-flow nasal cannula oxygen (HFNC) has the potential to provide apnoeic oxygenation. We decided to assess in a proof-of-concept study whether the addition of HFNC to non-invasive ventilation (NIV) could reduce oxygen desaturation during intubation, compared with NIV alone for preoxygenation, in severely hypoxaemic intensive care unit (ICU) patients with respiratory failure.

Methods

We conducted a randomised, controlled, single-centre trial with assessor-blinded outcome assessment in patients admitted to the ICU. Hypoxaemic patients requiring orotracheal intubation for respiratory failure were randomised to receive preoxygenation using HFNC [flow = 60 L/min, fraction of inspired oxygen (FiO₂) = 100 %] combined with NIV (pressure support = 10 cmH₂O, positive end-expiratory pressure = 5 cmH₂O, FiO₂ = 100 %) in the intervention group or NIV alone in the reference group prior to intubation. The primary outcome was the lowest oxygen saturation (SpO₂) during the intubation procedure. Secondary outcomes were intubation-related complications and ICU mortality.

Results

Between July 2015 and February 2016, we randomly assigned 25 and 24 patients to the intervention and reference groups, respectively. In both groups the main reasons for respiratory failure were pneumonia and ARDS. During the intubation procedure, the lowest SpO₂ values were significantly higher in the intervention group than in the reference group [100 (95–100) % vs. 96 (92–99) %, p = 0.029]. After exclusion of two patients from analysis for protocol violation, no (0 %) patients in the intervention group and five (21 %) patients in the reference group had SpO₂ below 80 % (p = 0.050). We recorded no significant difference between the groups in intubation-related complications or ICU mortality.

Conclusions

A novel strategy for preoxygenation in hypoxaemic patients, adding HFNC for apnoeic oxygenation to NIV prior to orotracheal intubation, may be more effective in reducing the severity of oxygen desaturation than the reference method using NIV alone.