Dyspnea is severe and associated with a higher intubation rate in de novo acute hypoxemic respiratory failure

BACKGROUND

Dyspnea is a key symptom of de novo acute hypoxemic respiratory failure. This study explores dyspnea and its association with intubation and mortality in this population.

METHODS

This was a secondary analysis of a multicenter, randomized, controlled trial. Dyspnea was quantified by a visual analog scale (dyspnea-VAS) from zero to 100 mm. Dyspnea was measured in 259 of the 310 patients included. Factors associated with intubation were assessed with a competing risks model taking into account ICU discharge. The Cox model was used to evaluate factors associated with 90-day mortality.

RESULTS

At baseline (randomization in the parent trial), median dyspnea-VAS was 46 (interquartile range, 16-65) mm and was ≥ 40 mm in 146 patients (56%). The intubation rate was 45%. Baseline variables independently associated with intubation were moderate (dyspnea-VAS 40-64 mm) and severe (dyspnea-VAS ≥ 65 mm) dyspnea at baseline (sHR 1.96 and 2.61, p = 0.023), systolic arterial pressure (sHR 2.56, p < 0.001), heart rate (sHR 1.94, p = 0.02) and PaO2/FiO2 (sHR 0.34, p = 0.028). 90-day mortality was 20%. The cumulative probability of survival was lower in patients with baseline dyspnea-VAS ≥ 40 mm (logrank test, p = 0.049). Variables independently associated with mortality were SAPS 2 ≥ 25 (p < 0.001), moderate-to-severe dyspnea at baseline (p = 0.073), PaO2/FiO2 (p = 0.118), and treatment arm (p = 0.046).

CONCLUSIONS

In patients admitted to the ICU for de novo acute hypoxemic respiratory failure, dyspnea is associated with a higher risk of intubation and with a higher mortality.

TRIAL REGISTRATION

clinicaltrials.gov Identifier # NCT01320384.

Development of clinical tools to estimate the breathing effort during high-flow oxygen therapy: A multicenter cohort study

INTRODUCTION AND OBJECTIVES

Quantifying breathing effort in non-intubated patients is important but difficult. We aimed to develop two models to estimate it in patients treated with high-flow oxygen therapy.

PATIENTS AND METHODS

We analyzed the data of 260 patients from previous studies who received high-flow oxygen therapy. Their breathing effort was measured as the maximal deflection of esophageal pressure (ΔPes). We developed a multivariable linear regression model to estimate ΔPes (in cmH2O) and a multivariable logistic regression model to predict the risk of ΔPes being >10 cmH2O. Candidate predictors included age, sex, diagnosis of the coronavirus disease 2019 (COVID-19), respiratory rate, heart rate, mean arterial pressure, the results of arterial blood gas analysis, including base excess concentration (BEa) and the ratio of arterial tension to the inspiratory fraction of oxygen (PaO2:FiO2), and the product term between COVID-19 and PaO2:FiO2.

RESULTS

We found that ΔPes can be estimated from the presence or absence of COVID-19, BEa, respiratory rate, PaO2:FiO2, and the product term between COVID-19 and PaO2:FiO2. The adjusted R2 was 0.39. The risk of ΔPes being >10 cmH2O can be predicted from BEa, respiratory rate, and PaO2:FiO2. The area under the receiver operating characteristic curve was 0.79 (0.73-0.85). We called these two models BREF, where BREF stands for BReathing EFfort and the three common predictors: BEa (B), respiratory rate (RE), and PaO2:FiO2 (F).

CONCLUSIONS

We developed two models to estimate the breathing effort of patients on high-flow oxygen therapy. Our initial findings are promising and suggest that these models merit further evaluation.

Efficacy of a surgical mask during high-flow nasal oxygen therapy in preventing aerosol dispersion: a randomized controlled study

PURPOSE

It is not clear whether or not high-flow nasal oxygenation used in patients with severe respiratory tract infection, or coughing, increases the risk of infection to the healthcare personnel, and whether or not applying a surgical mask to the patient's face or treating the patient in a negative-pressure room can reduce the risk.

METHODS

In a randomized crossover design, we compared in 50 participants receiving high-flow nasal oxygenation, the aerosol counts measured at approximately 20 cm above the participant's mouth in 32 different circumstances (with or without coughing, with or without wearing a surgical mask, at four different flow rates of oxygenation, in a positive- or negative-pressure operating room).

RESULTS

In a positive-pressure room, a surgical mask significantly decreased the aerosol counts during coughing (P = 0.0005), or during no coughing (P = 0.009), under high-flow nasal oxygenation (at 60 l.min-1). In the negative-pressure room, the aerosol count was significantly lower than in the positive-pressure room, for all the circumstances (all P < 0.001), and a surgical mask significantly decreased the aerosol counts during coughing (P = 0.047) but not during no coughing (P = 0.60).

CONCLUSION

In conclusion, treating a patient in a negative-pressure room, or applying a surgical mask, during high-flow nasal oxygenation (with the flow rate of 60 l.min-1) would inhibit, but would not completely prevent, dispersion of aerosols by coughing.

Use of high-flow oxygen therapy in a cat with cardiogenic pulmonary edema

Case summary

A 7-month-old female spayed domestic shorthair cat was presented for respiratory distress due to cardiogenic pulmonary edema. Despite initial treatment and oxygen delivery in an oxygen tent, the cat still showed signs of severe respiratory effort and oxygen saturation measured via pulse oximetry was below 85%. Because the owners declined mechanical ventilation, the cat was transitioned to high-flow oxygen therapy (HFOT). HFOT allowed significant improvement of the respiration parameters within 15 mins without causing clinical complications. The cat was briefly anaesthetised for the placement of the nasal cannula on initiation of HFOT, and the interface was well tolerated thereafter. The cat was transitioned to an oxygen cage after 16 h, weaned from oxygen 4 h later and was discharged after 3 days of hospitalisation. Long-term follow-up showed no abnormalities, and the leading hypothesis was transient myocardial thickening.

Relevance and novel information

The first use of HFOT in a dyspneic cat is described in this study. HFOT could be a life-saving option for cats with severe hypoxemia or do-not-intubate orders that fail to respond to conventional oxygen therapies.

High-flow oxygen therapy versus facemask preoxygenation in anticipated difficult airway management (PREOPTI-DAM): an open-label, single-centre, randomised controlled phase 3 trial

Background

Difficult airway management remains a critical procedure with life-threatening adverse events. Current guidelines suggest high-flow therapy by nasal cannulae (HFNC) as a preoxygenation device in this setting. However, there is an evidence gap to support this recommendation.

Methods

The PREOPTI-DAM study is an open-label, single-centre, randomised controlled phase 3 trial done at Nantes University Hospital, France. Patients were aged 18-90 years with one major or two minor criteria of anticipated difficult airway management, and requiring intubation for scheduled surgery, were eligible. Patients with body mass index >35 kg/m² were excluded. Patients were randomly allocated (1:1) to receive 4-min preoxygenation by HFNC or facemask. Randomisation was stratified according to the intubation strategy (laryngoscopic versus fiberoptic intubation). The primary outcome was the incidence of oxygen desaturation ≤94% or of bag-mask ventilation during intubation. The primary and safety analyses included the intention to treat population. This trial is registered with ClinicalTrials.gov (NCT03604120) and EudraCT (2018-A00434-51).

Findings

From September 4 2018 to March 31 2021, 186 patients were enrolled and randomly assigned. One participant withdrew consent and 185 (99.5%) were included in the primary analysis (HFNC, N = 95; Facemask, N = 90). The incidence of the primary outcome was not significantly different between the HFNC and the facemask groups, respectively 2 (2%) versus 7 (8%); adjusted difference, -5.6 [95% confidence interval (CI), -11.8 to 0.6], P = 0.10. In the HFNC group, 76 patients (80%) versus 53 (59%) in the facemask group, reported good or excellent intubation experiences; adjusted difference 20.5 [95% CI, 8.3-32.8], P = 0.016. Comparing HFNC with facemask, severe complication occurred in 22 (23%) versus 27 (30%) patients (P = 0.29), and moderate complication in 14 (15%) versus 18 (20%) patients (P = 0.35). No death or cardiac arrest occurred during the study.

Interpretation

Compared with facemask, HFNC did not significantly reduce the incidence of desaturation ≤94% or bag-mask ventilation during anticipated difficult intubation but the trial was underpowered to rule out a clinically significant benefit. Patient satisfaction was improved with HFNC.

Funding

Nantes University Hospital and Fisher & Paykel Healthcare.

High-flow oxygen therapy in elderly patients infected with SARS-CoV2 with a contraindication for transfer to an intensive care unit: A preliminary report

OBJECTIVES

In a conventional hospital ward, we used high-flow nasal oxygen (HFNO) to treat elderly COVID-19 patients noneligible for intensive care unit transfer.

METHODS

This study was conducted in the Institut Hospitalo-Universitaire Méditerranée Infection, Assistance Publique-Hôpitaux de Marseille (AP-HM), France. We used high-flow nasal oxygen (HFNO) in our conventional infectious disease ward from 15 September 2020 for elderly patients noneligible for intensive care unit transfer.

RESULTS

Of the 44 patients (median age 83 years (57-94), mean: 80.25), 61.4% (27/44) were men. The median Charlson score was 7 (1-15). The median of the NEWS-2 score upon admission was 8 (3-11) and was 10 at the time of initiation of HFNO. The median PaO2/FiO2 ratio was 103 (71-151) prior to HNFO initiation. Among the 44 patients, 16 patients (36.4%) had been weaned from HFNO, and 28 patients had died (63.6%).

CONCLUSIONS

In this preliminary report, we observed that HFNO saved the lives of one-third of elderly COVID-19 patients who would have systematically died.

Comparison of hypoxemia, intubation procedure, and complications for non-invasive ventilation against high-flow nasal cannula oxygen therapy for patients with acute hypoxemic respiratory failure: a non-randomized retrospective analysis for effectiveness and safety (NIVaHIC-aHRF)

BACKGROUND

Optimization of preoxygenation procedure can help to secure the method of intubation by reducing the risks of severe hypoxemia and other problems. There is confusion for efficacy of non-invasive ventilation compared to high-flow oxygen therapy regarding occurrence of severe hypoxemia during the intubation procedure. The purpose of the study was to compare the difference between noninvasive ventilation and high flow oxygen therapy to prevent desaturation during laryngoscopy.

METHODS

Patients underwent high-flow nasal cannula oxygen therapy (HCO cohort, n = 161) or non-invasive ventilation procedure (NIV cohort, n = 154) for oxygenation and ventilation due to acute hypoxemic respiratory failure in the intensive care unit. Data before preoxygenation, preoxygenation, intubation, laryngoscopy, and complications of patients due to tracheal intubation were retrospectively collected and analyzed.

RESULTS

There was no difference between both cohorts for the demographical and clinical conditions of the patients before preoxygenation (p > 0.05 for all parameters), numbers of patients with severe hypoxia during the intubation procedure (35 vs. 45, p = 0.303), the time duration of laryngoscopy (p = 0.847), number of laryngoscopies attempts (p = 0.804), and immediate and late complications during the intubation procedure. The values of pulse oximetry were reported higher for patients of NIV cohort than those of HCO cohort during preoxygenation. Fewer numbers of patients were reported with severe hypoxia among patients of the NIV cohort than those of the HCO cohort (24 vs., 40, p = 0.042) who have moderate-to-severe hypoxemia (partial pressure of arterial oxygen to fraction of inspired oxygen ratio ≤ 200 mmHg) before preoxygenation. The most common complications were hypertension, pulmonary aspiration, and increased 30-day mortality.

CONCLUSIONS

When compared, there was no difference between non-invasive ventilation technique and high-flow oxygen therapy to minimize severe hypoxia prior to laryngoscopy and endotracheal intubation in patients with acute respiratory failure.

Respiratory and pharmacological management in severe acute bronchiolitis: Were clinical guidelines not written for critical care?

PURPOSE

The treatment applied for children admitted to the pediatric intensive care unit (PICU) for severe acute bronchiolitis may differ from general recommendations. The first objective of our study was to describe the treatments offered to these children in a Spanish tertiary PICU. The second objective was to analyse the changes in management derived from the publication of the American Academy of Pediatrics (AAP) bronchiolitis guideline in 2014.

METHODS

This was a retrospective-prospective observational study conducted during two epidemic waves (2014-2015 and 2015-2016). The AAP guidelines were distributed and taught to PICU staff between both epidemic waves.

RESULTS

A total of 138 children were enrolled (78 male). In the first period, 78 children were enrolled. The median age was 1.8 months (IQR 1.1-3.6). There were no differences between the management in the two periods, except for the use of high-flow oxygen therapy (HFOT); its use increased in the second period. Overall, 83% of patients received non-invasive ventilation or HFOT. Children older than 12 months received HFOT exclusively. In comparison, continuous positive airway pressure and bi-level positive airway pressure were used less during the period 2015-2016 (P=0.036). Regarding pharmacological therapy, 70% of patients received antibiotics, 23% steroids, 33% salbutamol, 31% adrenaline, and 7% hypertonic saline. The mortality rate was zero.

CONCLUSIONS

Our PICU did not follow the AAP recommendations. There were no differences between the two periods, except in the use of HFOT. All children older than 12 months received HFOT exclusively. The rate of using invasive mechanical ventilation was also low.

Preventive use of respiratory support after scheduled extubation in critically ill medical patients-a network meta-analysis of randomized controlled trials

BACKGROUND

Respiratory support has been increasingly used after extubation for the prevention of re-intubation and improvement of prognosis in critically ill medical patients. However, the optimal respiratory support method is still under debate. This network meta-analysis (NMA) aims to evaluate the comparative effectiveness of various respiratory support methods used for preventive purposes after scheduled extubation in critically ill medical patients.

METHODS

A systematic database search was performed from inception to December 19, 2019, for randomized controlled trials (RCTs) that compared a preventive use of different respiratory support methods, including conventional oxygen therapy (COT), noninvasive ventilation (NIV), high-flow oxygen therapy (HFOT), and combinational use of HFOT and NIV (HFOT+NIV), after planned extubation in adult critically ill medical patients. Study selection, data extraction, and quality assessments were performed in duplicate. The primary outcomes included re-intubation rate and short-term mortality.

RESULTS

Seventeen RCTs comprising 3341 participants with 4 comparisons were included. Compared with COT, NIV significantly reduced the re-intubation rate [risk ratio (RR) 0.55, 95% confidence interval (CI) 0.39 to 0.77; moderate quality of evidence] and short-term mortality (RR 0.66, 95% CI 0.48 to 0.91; moderate quality of evidence). Compared to COT, HFOT had a beneficial effect on the re-intubation rate (RR 0.55, 95% CI 0.35 to 0.86; moderate quality of evidence) but no effect on short-term mortality (RR 0.79, 95% CI 0.56 to 1.12; low quality of evidence). No significant difference in the re-intubation rate or short-term mortality was found among NIV, HFOT, and HFOT+NIV. The treatment rankings based on the surface under the cumulative ranking curve (SUCRA) from best to worst for re-intubation rate were HFOT+NIV (95.1%), NIV (53.4%), HFOT (51.2%), and COT (0.3%), and the rankings for short-term mortality were NIV (91.0%), HFOT (54.3%), HFOT+NIV (43.7%), and COT (11.1%). Sensitivity analyses of trials with a high risk of extubation failure for the primary outcomes indicated that the SUCRA rankings were comparable to those of the primary analysis.

CONCLUSIONS

After scheduled extubation, the preventive use of NIV is probably the most effective respiratory support method for comprehensively preventing re-intubation and short-term death in critically ill medical patients, especially those with a high risk of extubation failure.

High-flow Nasal Cannula-induced Tension Pneumocephalus

High-flow nasal cannula (HFNC) therapy has been established as a promising oxygen treatment with various advantages for respiratory mechanics. One of the main mechanisms is to provide positive airway pressure. This effect could reduce lung injury and improve oxygenation; conversely, it may cause a complication of positive pressure ventilation. However, data are scarce regarding the possible adverse effects, particularly in adults. We report a patient who developed HFNC-induced tension pneumocephalus from an unrecognized skull base fracture. Physicians should be cautious when applying HFNC to patients with suspected skull base or paranasal sinus fracture, especially when applying a higher flow rate.

Effects of high-flow nasal cannula and non-invasive ventilation on inspiratory effort in hypercapnic patients with chronic obstructive pulmonary disease: a preliminary study

Background

Non-invasive ventilation (NIV) is preferred as the initial ventilatory support to treat acute hypercapnic respiratory failure in patients with chronic obstructive pulmonary disease (COPD). High-flow nasal cannula (HFNC) may be an alternative method; however, the effects of HFNC in hypercapnic COPD are not well known. This preliminary study aimed at assessing the physiologic effects of HFNC at different flow rates in hypercapnic COPD and to compare it with NIV.

Methods

A prospective physiologic study enrolled 12 hypercapnic COPD patients who had initially required NIV, and were ventilated with HFNC at flow rates increasing from 10 to 50 L/min for 15 min in each step. The primary outcome was the effort to breathe estimated by a simplified esophageal pressure–time product (sPTP_es). The other studied variables were respiratory rate, oxygen saturation (SpO₂), and transcutaneous CO₂ pressure (PtcCO₂).

Results

Before NIV initiation, the median [interquartile range] pH was 7.36 [7.28–7.37] with a PaCO₂ of 51 [42–60] mmHg. sPTP_es per minute was significantly lower with HFNC at 30 L/min than 10 and 20 L/min (p < 0.001), and did not significantly differ with NIV (median inspiratory/expiratory positive airway pressure of 11 [10–12] and [5–5] cmH₂O, respectively). At 50 L/min, sPTPes per minute increased compared to 30 L/min half of the patients. Respiratory rate was lower (p = 0.003) and SpO₂ was higher (p = 0.028) with higher flows (30–50 L/min) compared to flow rate of 10 L/min and not different than with NIV. No significant differences in PtcCO₂ between NIV and HFNC at different flow rates were observed (p = 0.335).

Conclusions

Applying HFNC at 30 L/min for a short duration reduces inspiratory effort in comparison to 10 and 20 L/min, and resulted in similar effect than NIV delivered at modest levels of pressure support in hypercapnic COPD with mild to moderate exacerbation. Higher flow rates reduce respiratory rate but sometimes increase the effort to breathe. Using HFNC at 30 L/min in hypercapnic COPD patients should be further evaluated. Trial registration Thai Clinical Trials Registry, TCTR20160902001. Registered 31 August 2016, http://www.clinicaltrials.in.th/index.php?tp=regtrials&menu=trialsearch&smenu=fulltext&task=search&task2=view1&id=2008.

Comparison of high-flow oxygen therapy with standard oxygen therapy for prevention of postoperative pulmonary complications after major head and neck surgery involving insertion of a tracheostomy: a feasibility study

Major operations on the head and neck that involve microvascular reconstruction and a tracheostomy are prolonged procedures with considerable postoperative risk. Postoperative pulmonary complications are common because of mechanical ventilation, immobility, and inadequate humidification. High-flow heated oxygen therapy (HFOT) may overcome some of these issues, but we know of no published studies to support its use. The aim of this single-site randomised controlled trial therefore was to explore its feasibility and safety in these patients. Twenty patients were randomised to have HFOT (10 patients) or standard oxygen therapy (10 patients). HFOT was used from cessation of mechanical ventilation until decannulation of the tracheostomy. The primary outcome was feasibility. The secondary outcome measures explored the incidence of postoperative pulmonary complications, achievement of milestones of weaning from the tracheostomy, and hospital length of stay. A total of 21 patients were consecutively recruited and all provided informed consent. One who did not require a tracheostomy was later excluded. All patients initially had the intervention as planned, and one was electively changed to the control group because of discomfort caused by the high-flow oxygen. There were no adverse events or safety concerns in either group. Secondary outcomes showed a reduction in the incidence of pulmonary complications in the HFOT group. The use of HFOT is safe and feasible in patients who have microvascular reconstruction of the head and neck and a tracheostomy.

Early high-flow nasal cannula oxygen therapy in adults with acute hypoxemic respiratory failure in the ED: A before-after study

OBJECTIVES

To compare clinical impact after early initiation of high-flow nasal cannula oxygen therapy (HFNC) versus standard oxygen in patients admitted to an emergency department (ED) for acute hypoxemic respiratory failure.

METHODS

We performed a prospective before-after study at EDs in two centers including patients with acute hypoxemic respiratory failure defined by a respiratory rate above 25 breaths/min or signs of increased breathing effort under additional oxygen for a pulse oximetry above 92%. Patients with cardiogenic pulmonary edema or exacerbation of chronic lung disease were excluded. All patients were treated with standard oxygen during the first period and with HFNC during the second. The primary outcome was the proportion of patients with improved respiratory failure 1 h after treatment initiation (respiratory rate ≤ 25 breaths/min without signs of increased breathing effort). Dyspnea and blood gases were also assessed.

RESULTS

Among the 102 patients included, 48 were treated with standard oxygen and 54 with HFNC. One hour after treatment initiation, patients with HFNC were much more likely to recover from respiratory failure than those treated with standard oxygen: 61% (33 of 54 patients) versus 15% (7 of 48 patients), P < 0.001. They also showed greater improvement in oxygenation (increase in PaO₂ was 31 mm Hg [0-67] vs. 9 [-9-36], P = 0.02), and in feeling of breathlessness.

CONCLUSIONS

As compared to standard oxygen, patients with acute hypoxemic respiratory failure treated with HFNC at the ED had better oxygenation, less breathlessness and were more likely to show improved respiratory failure 1 h after initiation.

Early nasal high-flow versus Venturi mask oxygen therapy after lung resection: a randomized trial

Background

Data on high-flow nasal oxygen after thoracic surgery are limited and confined to the comparison with low-flow oxygen. Different from low-flow oxygen, Venturi masks provide higher gas flow at a predetermined fraction of inspired oxygen (FiO₂). We conducted a randomized trial to determine whether preemptive high-flow nasal oxygen reduces the incidence of postoperative hypoxemia after lung resection, as compared to Venturi mask oxygen therapy.

Methods

In this single-center, randomized trial conducted in a teaching hospital in Italy, consecutive adult patients undergoing thoracotomic lung resection, who were not on long-term oxygen therapy, were randomly assigned to receive high-flow nasal or Venturi mask oxygen after extubation continuously for two postoperative days. The primary outcome was the incidence of postoperative hypoxemia (i.e., ratio of the partial pressure of arterial oxygen to FiO₂ (PaO₂/FiO₂) lower than 300 mmHg) within four postoperative days.

Results

Between September 2015 and April 2018, 96 patients were enrolled; 95 patients were analyzed (47 in high-flow group and 48 in Venturi mask group). In both groups, 38 patients (81% in the high-flow group and 79% in the Venturi mask group) developed postoperative hypoxemia, with an unadjusted odds ratio (OR) for the high-flow group of 1.11 [95% confidence interval (CI) 0.41–3] (p = 0.84). No inter-group differences were found in the degree of dyspnea nor in the proportion of patients needing oxygen therapy after treatment discontinuation (OR 1.34 [95% CI 0.60–3]), experiencing pulmonary complications (OR 1.29 [95% CI 0.51–3.25]) or requiring ventilatory support (OR 0.67 [95% CI 0.11–4.18]). Post hoc analyses revealed that PaO₂/FiO₂ during the study was not different between groups (p = 0.92), but patients receiving high-flow nasal oxygen had lower arterial pressure of carbon dioxide, with a mean inter-group difference of 2 mmHg [95% CI 0.5–3.4] (p = 0.009), and were burdened by a lower risk of postoperative hypercapnia (adjusted OR 0.18 [95% CI 0.06–0.54], p = 0.002).

Conclusions

When compared to Venturi mask after thoracotomic lung resection, preemptive high-flow nasal oxygen did not reduce the incidence of postoperative hypoxemia nor improved other analyzed outcomes. Further adequately powered investigations in this setting are warranted to establish whether high-flow nasal oxygen may yield clinical benefit on carbon dioxide clearance.

Trial registration

ClinicalTrials.gov, NCT02544477. Registered 9 September 2015.

Electronic supplementary material

The online version of this article (10.1186/s13054-019-2361-5) contains supplementary material, which is available to authorized users.

High-flow oxygen therapy in tracheostomized patients at high risk of weaning failure

Purpose

High-flow oxygen therapy delivered through nasal cannulae improves oxygenation and decreases work of breathing in critically ill patients. Little is known of the physiological effects of high-flow oxygen therapy applied to the tracheostomy cannula (T-HF). In this study, we compared the effects of T-HF or conventional low-flow oxygen therapy (conventional O₂) on neuro-ventilatory drive, work of breathing, respiratory rate (RR) and gas exchange, in a mixed population of tracheostomized patients at high risk of weaning failure.

Methods

This was a single-center, unblinded, cross-over study on fourteen patients. After disconnection from the ventilator, each patient received two 1-h periods of T-HF (T-HF1 and T-HF2) alternated with 1 h of conventional O₂. The inspiratory oxygen fraction was titrated to achieve an arterial O₂ saturation target of 94–98% (88–92% in COPD patients). We recorded neuro-ventilatory drive (electrical diaphragmatic activity, EAdi), work of breathing (inspiratory muscular pressure–time product per breath and per minute, PTP_musc/b and PTP_musc/min, respectively) respiratory rate and arterial blood gases.

Results

The EAdi_peak remained unchanged (mean ± SD) in the T-HF1, conventional O₂ and T-HF2 study periods (8.8 ± 4.3 μV vs 8.9 ± 4.8 μV vs 9.0 ± 4.1 μV, respectively, p = 0.99). Similarly, PTP_musc/b and PTP_musc/min, RR and gas exchange remained unchanged.

Conclusions

In tracheostomized patients at high risk of weaning failure from mechanical ventilation, T-HF did not improve neuro-ventilatory drive, work of breathing, respiratory rate and gas exchange compared with conventional O₂ after disconnection from the ventilator. The present findings might suggest that physiological effects of high-flow therapy through tracheostomy substantially differ from nasal high flow.

Heated humidified high-flow nasal oxygen prevents intraoperative body temperature decrease in non-intubated thoracoscopy

PURPOSE

In patients receiving non-intubated video-assisted thoracic surgery (NIVATS), transnasal humidified rapid-insufflation ventilatory exchange (THRIVE) has been applied instead of oxygen mask for better oxygenation. However, the THRIVE effects on intraoperative temperature decrease have not been investigated.

METHODS

Pre- and postoperative temperatures, measured by an infrared tympanic ear thermometer, taken before sending patients to the operation room and immediately upon their arrival in the postoperative anesthesia unit, were collected from medical records of patients who received NIVATS either with oxygen mask or THRIVE. Intraoperative temperature decrease, calculated by preoperative temperature minus postoperative temperature, was compared between different groups. Multiple linear regression analysis was performed to determine factors associated with intraoperative temperature decrease.

RESULTS

Records of 256 adult patients with forced-air warming were retrospectively analyzed. 172 patients of them received THRIVE and 84 patients received oxygen mask. Preoperative temperatures were comparable between groups (THRIVE: 36.25 ± 0.46 °C; mask: 36.30 ± 0.39 °C, p = 0.43). Postoperative temperatures were significantly higher in patients using THRIVE than those using oxygen masks (36.05 ± 0.59 vs 35.87 ± 0.62 °C, p = 0.025). Significantly less intraoperative temperature decrease was shown in THRIVE group (THRIVE: 0.20 ± 0.69 °C; mask: 0.43 ± 0.69 °C, p = 0.04). According to the multiple linear regression analysis, significant temperature decrease was associated with the advanced age (β_age = 0.01) but not the anesthetic duration. Using THRIVE was correlated with significantly less body temperature decrease (β_TRIVE = - 0.24).

CONCLUSIONS

THRIVE effectively prevents intraoperative temperature decrease during NIVATS, especially in old patients.

[Treatment with high-flow oxygen therapy in asthma exacerbations in a paediatric hospital ward: Experience from 2012 to 2016]

OBJECTIVE

To assess the experience with oxygen therapy with a high flow nasal cannula (HFNC) in hospital on patients with asthmatic exacerbation (AE) in a paediatric ward, and to assess the clinical outcome according with the initial oxygen flow (15lpm or <15lpm).

METHODS

This was a retrospective study of children aged 4 to 15 years with AE admitted to a paediatric ward in a tertiary level hospital between 2012 and 2016. Two groups of patients were compared; Group 1: patients treated with HFNC, and Group 2: patients treated with conventional oxygen therapy. A logistic regression model was constructed in order to identify predictive variables of HFNC. The clinical outcome of the patients was also compared according to the initial flow of HFNC (15lpm VS <15lpm).

RESULTS

The study included a total of 536 patients with AE, 40 (7.5%) of whom required HFNC. The median age was 5 (4-6) years. Heart rate (HR), respiratory rate (RR) and Pulmonary Score (PS) significantly decreased at 3-6hours after starting HFNC in Group 1. In the multivariate analysis, patients with high Pulmonary Score values and greater number of previous admissions required HFNC more frequently. Patients treated with an initial flow of 15lpm were admitted less frequently to the PICU than those with an initial flow less than 15lpm (13% vs 47%, p=.05).

CONCLUSION

HFNC seems to be a useful therapy for asthma exacerbation in paediatric wards. Severity of Pulmonary Score and the number of previous admissions could enable a risk group that needs HFNC to be identified.

High-flow nasal oxygen therapy and noninvasive ventilation in the management of acute hypoxemic respiratory failure

High-flow nasal cannula (HFNC) oxygen therapy is a recent technique delivering a high flow of heated and humidified gas. HFNC is simpler to use and apply than noninvasive ventilation (NIV) and appears to be a good alternative treatment for hypoxemic acute respiratory failure (ARF). HFNC is better tolerated than NIV, delivers high fraction of inspired oxygen (FiO₂), generates a low level of positive pressure and provides washout of dead space in the upper airways, thereby improving mechanical pulmonary properties and unloading inspiratory muscles during ARF. A recent multicenter randomized controlled trial showed benefits of HFNC concerning mortality and intubation in severe patients with hypoxemic ARF. In management of patients with hypoxemic ARF, NIV results have been conflicting. Despite improved oxygenation, NIV delivered with face mask may generate high tidal volumes and subsequent ventilator-induced lung injury. An approach applying NIV with a helmet, high levels of positive end-expiratory pressure (PEEP) and low pressure support (PS) levels seems to open new opportunities in patients with hypoxemic ARF. However, a large-scale randomized controlled study is needed to assess and compare this approach with HFNC.

High-flow nasal cannula oxygen therapy versus noninvasive ventilation in immunocompromised patients with acute respiratory failure: an observational cohort study

BACKGROUND

Acute respiratory failure is the main cause of admission to intensive care unit in immunocompromised patients. In this subset of patients, the beneficial effects of noninvasive ventilation (NIV) as compared to standard oxygen remain debated. High-flow nasal cannula oxygen therapy (HFNC) is an alternative to standard oxygen or NIV, and its use in hypoxemic patients has been growing. Therefore, we aimed to compare outcomes of immunocompromised patients treated using HFNC alone or NIV as a first-line therapy for acute respiratory failure in an observational cohort study over an 8-year period. Patients with acute-on-chronic respiratory failure, those treated with standard oxygen alone or needing immediate intubation, and those with a do-not-intubate order were excluded.

RESULTS

Among the 115 patients analyzed, 60 (52 %) were treated with HFNC alone and 55 (48 %) with NIV as first-line therapy with 30 patients (55 %) receiving HFNC and 25 patients (45 %) standard oxygen between NIV sessions. The rates of intubation and 28-day mortality were higher in patients treated with NIV than with HFNC (55 vs. 35 %, p = 0.04, and 40 vs. 20 %, p = 0.02 log-rank test, respectively). Using propensity score-matched analysis, NIV was associated with mortality. Using multivariate analysis, NIV was independently associated with intubation and mortality.

CONCLUSIONS

Based on this observational cohort study including immunocompromised patients admitted to intensive care unit for acute respiratory failure, intubation and mortality rates could be lower in patients treated with HFNC alone than with NIV. The use of NIV remained independently associated with poor outcomes.

The role of high flow oxygen therapy in acute respiratory failure

Acute respiratory failure represents one of the most common causes of intensive care unit admission and oxygen therapy remains the first-line therapy in the management of these patients. In recent years, high-flow oxygen via nasal cannula has been described as a useful alternative to conventional oxygen therapy in patients with acute respiratory failure. High-flow oxygen via nasal cannula rapidly alleviates symptoms of acute respiratory failure and improves oxygenation by several mechanisms, including dead space washout, reduction in oxygen dilution and inspiratory nasopharyngeal resistance, a moderate positive airway pressure effect that may generate alveolar recruitment and an overall greater tolerance and comfort with the interface and the heated and humidified inspired gases. However, the experience in adults is still limited and there are no clinical guidelines to establish recommendations for their use. This article aims to review the existing evidence on the use of high-flow oxygen via nasal cannula in adults with acute respiratory failure and its possible applications, advantages and limitations.

Feasibility of high-flow nasal cannula oxygen therapy for acute respiratory failure in patients with hematologic malignancies: A retrospective single-center study

PURPOSE

This study investigated the feasibility of high-flow nasal cannula (HFNC) oxygen therapy for acute respiratory failure in adult patients with hematologic malignancies.

MATERIALS AND METHODS

We identified 45 acute respiratory failure patients with hematologic malignancies who received HFNC therapy between March 2012 and June 2014 at Seoul St Mary's Hospital. Their medical records were reviewed retrospectively to identify useful prognostic factors for successful treatment.

RESULTS

Of the 45 patients, 15 (33.3%) successfully recovered, and 30 were changed to invasive ventilation due to failed HFNC treatment. The etiologies of acute respiratory failure were bacterial pneumonia (57.8%), Pneumocystis jirovecii pneumonia (17.8%), pulmonary edema (8.9%), and bronchiolitis obliterans organizing pneumonia (8.9%). The overall mortality rate was 62.2%. The HFNC treatment success rate was significantly different between the survivors and nonsurvivors. To evaluate risk factors for HFNC treatment failure, differences between the HFNC treatment success and failure groups were compared. There were no significant differences in the severity of underlying medical conditions. The percentage of bacterial pneumonia was significantly higher in the HFNC treatment failure group compared with the success group (73.3% vs 26.7%; P = .004).

CONCLUSIONS

High-flow nasal cannula offers an interesting alternative to invasive ventilation in acute respiratory failure patients with hematologic malignancies. However, attention must be paid to the appropriate choice of HFNC settings such as oxygen flow.