New method of preoxygenation for orotracheal intubation in patients with hypoxaemic acute respiratory failure in the intensive care unit, non-invasive ventilation combined with apnoeic oxygenation by high flow nasal oxygen: the randomised OPTINIV study protocol

Atelectasis prevention during anaesthesia using high-flow nasal cannula therapy: A paediatric randomised trial using MRI images

BACKGROUND

Atelectasis frequently occurs early on during anaesthesia in children. We hypothesised that positive expiratory pressure (PEP) generated via high-flow nasal cannula (HFNC) could prevent atelectasis in non-intubated children under general anaesthesia. The objective was to compare the volume of atelectasis present in patients treated via HFNC to that of patients treated via a face bag-mask without PEP. The outcome used for this comparison was the ratio of the atelectasis volume to the total pulmonary volume.

METHODS

A prospective single-centre, single-blind, randomised trial was conducted in a tertiary hospital from November 2018 through May 2019. The trial subjects were infants and children between six months and six years of age who required anaesthesia for an MRI. The children were randomised to receive sevoflurane for maintenance of anaesthesia either via a classic face bag-mask or by HFNC. The atelectasis volume was measured from thoracic MRI images. The judgement criterion was the ratio of the atelectasis volume to the lung volume.

RESULTS

Of a trial group of 42 patients, 21 received anaesthesia via a face bag-mask and 21 via HFNC. After three patients were excluded for technical issues, the data for 39 patients were analysed. The atelectasis volume to the lung volume ratio in the HFNC group was significantly smaller than the ratio for the face bag-mask group (1.6% vs 6.8%, respectively; p=0.002).

CONCLUSION

HFNC was associated with a lower atelectasis lung ratio compared to using a face bag-mask during anaesthesia for children maintained with spontaneous ventilation. Registered on Clinicaltrials.gov: NCT03592589.

Cardiac Arrest and Mortality Related to Intubation Procedure in Critically Ill Adult Patients: A Multicenter Cohort Study

OBJECTIVES

To determine the prevalence of and risk factors for cardiac arrest during intubation in ICU, as well as the association of ICU intubation-related cardiac arrest with 28-day mortality.

DESIGN

Retrospective analysis of prospectively collected data.

SETTING

Sixty-four French ICUs.

PATIENTS

Critically ill patients requiring intubation in the ICU.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

During the 1,847 intubation procedures included, 49 cardiac arrests (2.7%) occurred, including 14 without return of spontaneous circulation (28.6%) and 35 with return of spontaneous circulation (71.4%). In multivariate analysis, the main predictors of intubation-related cardiac arrest were arterial hypotension (systolic blood pressure < 90 mm Hg) prior to intubation (odds ratio = 3.406 [1.797-6.454]; p = 0.0002), hypoxemia prior to intubation (odds ratio = 3.991 [2.101-7.583]; p < 0.0001), absence of preoxygenation (odds ratio = 3.584 [1.287-9.985]; p = 0.0146), overweight/obesity (body mass index > 25 kg/m; odds ratio = 2.005 [1.017-3.951]; p = 0.0445), and age more than 75 years old (odds ratio = 2.251 [1.080-4.678]; p = 0.0297). Overall 28-day mortality rate was 31.2% (577/1,847) and was significantly higher in patients who experienced intubation-related cardiac arrest than in noncardiac arrest patients (73.5% vs 30.1%; p < 0.001). After multivariate analysis, intubation-related cardiac arrest was an independent risk factor for 28-day mortality (hazard ratio = 3.9 [2.4-6.3]; p < 0.0001).

CONCLUSIONS

ICU intubation-related cardiac arrest occurs in one of 40 procedures with high immediate and 28-day mortality. We identified five independent risk factors for cardiac arrest, three of which are modifiable, possibly to decrease intubation-related cardiac arrest prevalence and 28-day ICU mortality.

Effects of Preoxygenation with Tidal Volume Breathing Followed by Apneic Oxygenation with and without Continuous Positive Airway Pressure on Duration of Safe Apnea Time and Arterial Blood Gases

Background:

Application of continuous positive airway pressure (CPAP) helps to recruit collapsed areas of the lung, which improves the oxygen reserve.

Aim of the Study:

To compare the time to desaturate to 90% during apnea following preoxygenation and apneic ventilation with tidal volume breathing for 3 min with and without the application of CPAP.

Settings and Design:

This prospective randomized study was conducted in a tertiary care institution.

Subjects and Methods:

Twenty adult surgical patients were allocated into two groups. Group C patients were preoxygenated with 100% oxygen with CPAP of 20 cm H₂O for 3 min. Group P patients were preoxygenated for 3 min without CPAP. In Group C, apneic oxygenation was initiated following induction and neuromuscular blockade with CPAP of 20 cm H₂O. In Group P, no CPAP was applied. The study was terminated when the patient desaturated to 90%.

Statistical Analysis Used:

Chi-square test and Mann–Whitney test.

Results:

Group C had a significantly longer apnea time as compared to Group P (816.00 ± 30.98 vs. 348.00 ± 122.64 s). Three patients in Group P desaturated to <90% by 3 min and the remaining soon after 6 min. No patient in Group C desaturated till 12 min of apnea. PaO₂ was significantly higher in Group C at 3 and 6 min of apnea. At 3 and 6 min, Group P had significantly lower saturation as compared to Group C.

Conclusion:

Preoxygenation with CPAP significantly delayed desaturation during apnea with significantly higher arterial partial pressure of oxygen as compared to preoxygenation without CPAP.

Comparison of Arterial Oxygenation and Acid-Base Balance with the use of Transnasal Humidified Rapid-insufflation Ventilatory Exchange versus Tidal Volume Breathing with Continuous Positive Airway Pressure for Preoxygenation and Apneic Ventilation

Background:

Preoxygenation and apneic ventilation prolong apnea time without desaturation.

Aims:

The primary objective of this study is to compare arterial oxygenation during the periods of apnea following preoxygenation and apneic ventilation with tidal volume breathing for 3 min with continuous positive airway pressure (CPAP) versus with transnasal humidified rapid-insufflation ventilatory exchange (THRIVE).

Settings and Designs:

This prospective randomized study was conducted in 20 adult patients at a tertiary care institution.

Subjects and Methods:

Group C patients (n = 10) were preoxygenated with 100% oxygen using a face mask at a rate of 6 L/min for 3 min with CPAP of 15 cm of H₂O. In Group H, oxygen was administered using THRIVE at 30 L/min for 3 min. Apneic ventilation was given in Group C with 10 L/min oxygen with CPAP of 15 cm H₂O and in Group H with THRIVE at 60 L/min. The endpoint was desaturation to 90% or maximum duration of 12 min.

Statistical Analysis Used:

Chi-square test and Mann–Whitney test.

Results:

Both groups tolerated apnea for 12 min without desaturation. PaO₂ in Group C was significantly higher than Group H from 3 min of apnea to 12 min. The PaCO₂ was significantly lower in Group C from 6 min. The pH was comparable in both groups except at 12 min with Group H having significantly lower pH.

Conclusion:

Tidal volume breathing with CPAP resulted in significantly higher arterial oxygen levels than THRIVE, though both modalities were equally effective in prolonging apnea time without desaturation up to 12 min. Group C showed an added advantage of lower PaCO₂ with less acidemia.