High flow nasal cannula oxygen versus noninvasive ventilation in adult acute respiratory failure: a systematic review of randomized-controlled trials

The use of non-invasive respiratory assistance to facilitate bronchofiberoscopy performance in patients with hypoxemic (type one) respiratory failure - Study protocol

PURPOSE

Bronchofiberoscopy (FOB) is a procedure routinely performed for: lung cancer, obstruction, interstitial diseases, foreign bodies' removal, airway clearance, and hemoptysis. It causes acute airway narrowing leading to respiratory and cardiovascular stress. Due to increasing number of ill patients with respiratory failure (RF), conventional oxygen therapy (COT) is frequently insufficient to assure accurate oxygenation and prevent RF in patients requiring FOB. In this clinical scenario, patients may be intubated and supported with invasive mechanical ventilation (IMV) with the specific aim of allowing a safe FOB. However, this invasive strategy is associated with an increased risk of IMV-associated complications.

MATERIALS AND METHODS

Our study is a planned prospective multicenter three-arm randomized controlled trial (RCT). The target number of 300 patients was calculated based on the intubation risk in RF patients, which is 0.2-2%. The patients will be assigned to each arm based on Horowitz index. In each arm, the patients will be randomly assigned to one out of two dedicated respiratory support methods in each group i.e. COT/high flow nasal cannula (HFNC), HFNC/non-invasive ventilation (NIV) and NIV/IMV. In the manuscript the current state of art in the area of respiratory support is discussed. We have underlined knowledge gaps in medical evidence which we are planning to reveal with our results.

RESULTS

The results of our study are clinically crucial, because they address current gaps concerning COT/HFNC/NIV/IMV.

CONCLUSION

The expected findings of this study would allow for careful selection of respiratory support method to safely perform FOB in patients with hypoxemic RF.

High-flow nasal oxygen for suspension laryngoscopy: a multicenter open-label study

In this study, we aimed to assess the efficacy of high-flow nasal oxygen (HFNO) to maintain blood peripheral oxygen saturation (SpO2) in patients undergoing suspension laryngoscopy under general anesthesia. Adult patients were included in this bicenter study. After face-mask oxygenation, HFNO at a flow rate of 70 L min^-1 and fraction of inspired oxygen 100% was initiated at loss of consciousness. At the end of HFNO, blood gas analysis was performed. Of the 29 included patients, five (17.2%; 95% confidence interval [CI]: 7.6-34.5) presented SpO2 <95% during the first 15 minutes of the procedure and eight patients (27.6%; 95% CI: 14.7-45.7) presented SpO2 <95% throughout the procedure. Six patients (20.7%; 95% CI: 9.8-38.4) required rescue jet ventilation. Median apnea time before SpO2 <95% was 13.5 (interquartile range [IQR]: 10-17.7) minutes. Arterial carbon dioxide tension at the end of the procedure or at the time of study discontinuation was 9.73 (IQR: 8.8-10.9) kPa and was higher than 8 kPa in 88.9% (95% CI: 71.9-96.1) of patients. HFNO was associated with a relatively high incidence of suboptimal oxygen saturation and hypercapnia during suspension laryngoscopy under general anesthesia and may not be considered the reference technique.

The Impact of High-flow Nasal Cannula vs Other Oxygen Delivery Devices during Bronchoscopy under Sedation: A Systematic Review and Meta-analyses

Background

The widespread diagnostic and therapeutic application of bronchoscopy is often associated with complications like desaturation. This systematic review and meta-analysis intend to scrutinize whether the high-flow nasal cannula (HFNC) is advantageous for providing respiratory support during bronchoscopic procedures under sedation, in comparison with other conventional modalities for oxygen therapy.

Materials and methods

A thorough screening of electronic databases was done till 31st December 2021 after obtaining registration in PROSPERO (CRD42021245420). Randomized controlled trials (RCT), evaluating the impact of HFNC and standard/any other oxygen-delivery devices during bronchoscopy were included in this meta-analysis.

Results

We retrieved in nine RCTs, with a total of 1306 patients, the application of HFNC during bronchoscopy led to decreased number of desaturation spells [relative risk (RR) 0.34, 95% confidence interval (CI) 0.27-0.44, I ² = 23%], higher nadir value of SpO₂ [Mean difference (MD) 4.30, 95% CI 2.41-6.19, I ² = 96%], and improved PaO₂ from baseline (MD 21.77, 95% CI 2.8-40.74, I ² = 99%), along with similar PaCO₂ values (MD -0.34, 95% CI -1.82 to 1.13, I ² = 58%) just after the procedure. However, apart from desaturation spell, the findings are significantly heterogeneous. In subgroup analysis, HFNC had significantly lesser desaturation spells and better oxygenation than low-flow devices, but in comparison to noninvasive ventilation (NIV) had a lower nadir value of SpO₂ with no other significant difference.

Conclusion

High-flow nasal cannula led to greater oxygenation and prevented desaturation spells more effectively in comparison with low-flow devices like nasal cannula, venturi mask, etc., and may be considered as an alternative to NIV during bronchoscopy in certain high-risk patients.

How to cite this article

Roy A, Khanna P, Chowdhury SR, Haritha D, Sarkar S. The Impact of High-flow Nasal Cannula vs Other Oxygen Delivery Devices during Bronchoscopy under Sedation: A Systematic Review and Meta-analyses. Indian J Crit Care Med 2022;26(10):1131-1140.

Modified high-flow nasal cannula oxygen therapy versus conventional oxygen therapy in patients undergoing bronchoscopy: a randomized clinical trial

Background

Hypoxemia frequently occurs during bronchoscopy. High-flow nasal cannula (HFNC) oxygen therapy may be a feasible alternative to prevent the deterioration of gas exchange during bronchoscopy. With the convenience of clinical use in mind, we modified an HFNC using a single cannula. This clinical trial was designed to test the hypothesis that a modified HFNC would decrease the proportion of patients with a single moment of peripheral arterial oxygen saturation (SpO₂) < 90% during bronchoscopy.

Methods

In this single-center, prospective randomized controlled trial, hospitalized patients in the respiratory department in need of diagnostic bronchoscopy were randomly assigned to a modified HFNC oxygen therapy group or a conventional oxygen therapy (COT) group. The primary outcome was the proportion of patients with a single moment of SpO₂ < 90% during bronchoscopy.

Results

Eight hundred and twelve patients were randomized to the modified HFNC (n = 406) or COT (n = 406) group. Twenty-four patients were unable to cooperate or comply with bronchoscopy. Thus, 788 patients were included in the analysis. The proportion of patients with a single moment of SpO₂ < 90% during bronchoscopy in the modified HFNC group was significantly lower than that in the COT group (12.5% vs. 28.8%, p < 0.001). There were no significant differences in the fraction of inspired oxygen between the two groups. The lowest SpO₂ during bronchoscopy and 5 min after bronchoscopy in the modified HFNC group was significantly higher than that in the COT group. Multivariate analysis showed that a baseline forced vital capacity (FVC) < 2.7 L (OR, 0.276; 95% CI, 0.083–0.919, p = 0.036) and a volume of fluid instilled > 60 ml (OR, 1.034; 95% CI, 1.002–1.067, p = 0.036) were independent risk factors for hypoxemia during bronchoscopy in the modified HFNC group.

Conclusions

A modified HFNC could decrease the proportion of patients with a single moment of SpO₂ < 90% during bronchoscopy. A lower baseline FVC and large-volume bronchoalveolar lavage may predict desaturation during bronchoscopy when using a modified HFNC.

Trial registration ClinicalTrials. Gov: NCT02606188. Registered 17 November 2015.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01744-8.

A physiological approach to understand the role of respiratory effort in the progression of lung injury in SARS-CoV-2 infection

Deterioration of lung function during the first week of COVID-19 has been observed when patients remain with insufficient respiratory support. Patient self-inflicted lung injury (P-SILI) is theorized as the responsible, but there is not robust experimental and clinical data to support it. Given the limited understanding of P-SILI, we describe the physiological basis of P-SILI and we show experimental data to comprehend the role of regional strain and heterogeneity in lung injury due to increased work of breathing.

In addition, we discuss the current approach to respiratory support for COVID-19 under this point of view.

Effect of noninvasive ventilation on intubation risk in prehospital patients with acute cardiogenic pulmonary edema: a retrospective study

OBJECTIVE

The aim of this study was to assess the effect of prehospital noninvasive ventilation for acute cardiogenic pulmonary edema on endotracheal intubation rate and on ICU admission rate.

METHODS

We carried out a retrospective study on patients' prehospital files between 2007 and 2010 (control period), and between 2013 and 2016 (intervention period). Adult patients were included if a diagnosis of acute cardiogenic pulmonary edema was made by the prehospital physician. Exclusion criteria were a Glasgow coma scale score less than 9 or any other respiratory diagnosis. We analyzed the association between noninvasive ventilation implementation and endotracheal intubation or ICU admission with univariable and multivariable regression models. The primary outcome was prehospital endotracheal intubation rate. Secondary outcomes were admission to an ICU, prehospital intervention length, and 30-day mortality.

RESULTS

A total of 1491 patients were included. Noninvasive ventilation availability was associated with a significant decrease in endotracheal intubation rate (2.6% in the control versus 0.7% in the intervention period), with an adjusted odds ratio (OR) of 0.3 [95% confidence interval (CI), 0.1-0.7]. There was a decrease in ICU admissions (18.6% in the control versus 13.0% in the intervention period) with an adjusted OR of 0.6 (95% CI, 0.5-0.9). There was no significant change in 30-day mortality (11.2% in the control versus 11.0% in the intervention period, P = 0.901).

CONCLUSION

In our physician-staffed prehospital system, use of noninvasive ventilation for acute cardiogenic pulmonary edema decreased both endotracheal intubation and ICU admission rates.

Pneumonia

Pneumonia is a common cause of hospital admission and community-acquired pneumonia (CAP) is a growing health problem in developed country and worldwide. Elderly patients suffer from more severe disease, require intensive care unit (ICU) admission, and exhibit higher mortality compared with their younger counterparts. The immunological changes that occur with age called “immunosenescence” (decreased efficiency of the adaptive and innate immune systems) are known to be responsible for the increased susceptibility of elderly persons to infectious diseases and for their limited response to vaccines [1].