Explore the vast range of titles available.

PurposeMilitary parachute operations are often executed at high altitude, from an unpressurized aircraft compartment. Parachute jumpmasters (JM) are thus regularly exposed to 29,500 ft for 60 min. The aim was to investigate the decompression strain during a simulated JM mission at high altitude and to compare two strategies of preoxygenation, conducted either at sea-level or below 10,000 ft, during ascent to mission altitude.MethodsTen JM completed, on separate occasions, a 45-min preoxygenation either at sea-level (normobaric: N) or 8200ft (hypobaric: H), followed by exposure to 28,000 ft for 60 min, whilst laying supine and breathing 100% oxygen. At min 45 of the exposure to 28,000 ft, the JM performed 10 weighted squats. Decompression strain was determined from ultrasound assessment of venous gas emboli (VGE) during supine rest (5-min intervals), after three unloaded knee-bends (15-min intervals) and immediately following the weighted squats. The VGE were scored using a six-graded scale (0–5).ResultsIn condition H, two JM experienced decompression sickness (DCS), whereas no DCS incidents were reported in condition N. The prevalence of VGE was higher in the H than the N condition, at rest [median(range), 3(0–4) vs 0(0–3); p = 0.017], after unloaded knee-bends [3(0–4) vs 0(0–3); p = 0.014] and after the 10 weighted squats [3(0–4) vs 0(0–3); p = 0.014]. VGE were detected earlier in the H (28 ± 20 min, p = 0.018) than the N condition (50 ± 19 min).ConclusionsA preoxygenation/altitude procedure commonly used by JM, with a 60-min exposure to 28,000 ft after pre-oxygenation for 45 min at 8200 ft is associated with high risk of DCS. The decompression strain can be reduced by preoxygenating at sea level.

Preoxygenation is a crucial manoeuvre for patients’ safety, particularly for morbidly obese patients due to their reduced pulmonary reserve and increased risk for difficult airway situations. The oxygen reserve index (ORI™) was recently introduced as a new parameter of multiple wavelength pulse oximetry and has been advocated to allow assessment of hyperoxia [quantified by the resulting arterial oxygen partial pressure (PaO2)]. This study investigates if ORI can be used to evaluate the impact of two different preoxygenation manoeuvres on the grade of hyperoxia. Two preoxygenation manoeuvres were sequentially evaluated in 41 morbidly obese patients: First, breathing 100% oxygen for 5 min via standard face mask. Second, after achieving a second baseline, 5 min of non-invasive ventilation (NIV) with 100% oxygen. The effect of preoxygenation on ORI compared to PaO2 was evaluated and whether differences in the two preoxygenation manoeuvres can be monitored by ORI. Overall correlation of PaO2 and ORI was significant (Spearman-Rho coefficient of correlation 0.818, p < 0.001). However, ORI could not differentiate between the two preoxygenation manoeuvres although the PaO2 values for NIV preoxygenation were significantly higher compared to standard preoxygenation (median 505 mmHg (M1) vs. 550 mmHg (M3); p < 0.0001). In contrast, ORI values did not differ significantly (median 0.39 (M1) vs. 0.38 (M3); p = 0.758). Absolute values of ORI cannot be used to assess effectiveness of a preoxygenation procedure in bariatric patients, mainly because its range of discrimination is considerably lower than the high ranges of PaO2 attained by adequate preoxygenation. Trial registration German Clinical Trials Register: DRKS00025023 (retrospectively registered on April 16th, 2021).

Purpose Intubation of hypoxemic patients is associated with life-threatening adverse events. High-flow therapy by nasal cannula (HFNC) for preoxygenation before intubation has never been assessed by randomized study. Our objective was to evaluate the efficiency of HFNC for preoxygenation, compared to high fraction-inspired oxygen facial mask (HFFM). Methods Multicenter, randomized, open-labelled, controlled PREOXYFLOW trial (NCT 01747109) in six French intensive care units. Acute hypoxemic adults requiring intubation were randomly allocated to HFNC or HFFM. Patients were eligible if PaO 2 /FiO 2 ratio was below 300 mmHg, respiratory rate at least 30/min and if they required FiO 2 50 % or more to obtain at least 90 % oxygen saturation. HFNC was maintained throughout the procedure, whereas HFFM was removed at the end of general anaesthesia induction. Primary outcome was the lowest saturation throughout intubation procedure. Secondary outcomes included adverse events related to intubation, duration of mechanical ventilation and death. Results A total of 124 patients were randomized. In the intent-to-treat analysis, including 119 patients (HFNC n  = 62; HFFM n  = 57), the median (interquartile range) lowest saturation was 91.5 % (80–96) for HFNC and 89.5 % (81–95) for the HFFM group ( p  = 0.44). There was no difference for difficult intubation ( p  = 0.18), intubation difficulty scale, ventilation-free days ( p  = 0.09), intubation-related adverse events including desaturation <80 % or mortality ( p  = 0.46). Conclusions Compared to HFFM, HFNC as a preoxygenation device did not reduce the lowest level of desaturation.

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 (FiO 2 ) = 100 %] combined with NIV (pressure support = 10 cmH 2 O, positive end-expiratory pressure = 5 cmH 2 O, FiO 2  = 100 %) in the intervention group or NIV alone in the reference group prior to intubation. The primary outcome was the lowest oxygen saturation (SpO 2 ) 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 SpO 2 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 SpO 2 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.

The investigators did not provide information on how such “forced” ventilation was controlled (tidal volume, minute ventilation, negative inspiratory force, intrathoracic pressure) suggesting that the hemodynamic consequences of this maneuver were not standardized as is the case during positive pressure ventilation. From our perspective, this limitation in experimental design makes it impossible to draw any meaningful conclusions from the data. Because arterial oxygen tension was not measured during preoxygenation (only saturation was recorded), it was not possible to ascertain whether the potential hemodynamic impact of hyperoxia was comparable throughout the study.

PurposePreoxygenation with high-flow therapy by nasal cannulae (HFNC) is now widespread in the intensive care unit (ICU). However, no large randomized study has assessed its relevance in non-severely hypoxemic patients. In a randomized controlled trial (PROTRACH study), we aimed to evaluate preoxygenation with HFNC vs. standard bag-valve mask oxygenation (SMO) in non-severely hypoxemic patients during rapid sequence intubation (RSI) in the ICU.MethodsRandomized controlled trial including non-severely hypoxemic patients requiring intubation in the ICU. Patients received preoxygenation by HFNC or SMO during RSI. HFNC was maintained throughout the intubation procedure whereas SMO was removed to perform laryngoscopy. The primary outcome was the lowest pulse oximetry (SpO2) throughout the intubation procedure. Secondary outcomes included drop in SpO2, adverse events related to intubation, and outcome in the ICU.ResultsA total of 192 patients were randomized. In the intent-to-treat analysis, 184 patients (HFNC n = 95; SMO n = 89), the median [IQR] lowest SpO2 was 100% [97; 100] for HFNC and 99% [95; 100] for the SMO group (P = 0.30). Mild desaturation below 95% was more frequent with SMO (23%) than with HFNC (12%) (RR 0.51, 95% CI 0.26–0.99, P = 0.045). There were fewer adverse events in the HFNC group (6%) than in the SMO group (19%) (RR 0.31, 95% CI 0.13–0.76, P = 0.007), including fewer severe adverse events, respectively 6 (6%) and 14 (16%) with HFNC and SMO (RR 0.38, 95% CI 0.15–0.95, P = 0.03).ConclusionsCompared with SMO, preoxygenation with HFNC in the ICU did not improve the lowest SpO2 during intubation in the non-severely hypoxemic patients but led to a reduction in intubation-related adverse events.Trial registrationClinical trial Submission: 7 March 2016. Registry name: Benefits of high-flow nasal cannulae oxygen for preoxygenation during intubation in non-severely hypoxemic patients: the PROTRACH study. Clinicaltrials.gov identifier: NCT02700321. Eudra CT: 2015-A00145-44. CPP: 15/13-975 (Comité de protection des personnes de Rennes). URL registry: https://clinicaltrials.gov/ct2/show/record/NCT02700321.

Background Patients with acute hypoxemic respiratory failure are at risk for life-threatening complications during endotracheal intubation. Preoxygenation might help reduce the risk of hypoxemia and intubation-related complications. This network meta-analysis summarizes the efficacy and safety of preoxygenation methods in adult patients with acute hypoxemic respiratory failure. Methods We searched PubMed, EMBASE, and the Cochrane Library Central Register of Controlled Trials through April 2019 for randomized controlled trials (RCT) that studied the use of conventional oxygen therapy (COT), high-flow nasal cannula (HFNC), noninvasive ventilation (NIV), and HFNC and NIV as preoxygenation before intubation in patients with acute hypoxemic respiratory failure. Citations’ screening, study selection, data extraction, and risk of bias assessment were independently performed by two authors. The primary outcome was the lowest SpO 2 during the intubation procedure. Results We included 7 RCTs (959 patients). Patients preoxygenated with NIV had significantly less desaturation than patients treated with COT (mean difference, MD 5.53, 95% CI 2.71, 8.34) and HFNC (MD 3.58, 95% CI 0.59, 6.57). Both NIV (odds ratio, OR 0.43, 95% CI 0.21, 0.87) and HFNC (OR 0.49, 95% CI 0.28, 0.88) resulted in a lower risk of intubation-related complications than COT. There were no significant mortality differences among the use of NIV, HFNC, COT, and HFNC and NIV during preoxygenation. Conclusions In adult patients with acute hypoxemic respiratory failure, NIV is a safe and probably the most effective preoxygenation method.

Airway management including endotracheal intubation (ETI) is a key skill for emergency clinicians. Therefore, it is important for emergency clinicians to be aware of the current evidence regarding the identification and management of patients requiring ETI. This paper evaluates key evidence-based updates concerning ETI for the emergency clinician. ETI is commonly performed in the emergency department (ED) setting but has many nuanced components. There are several tools that have been used to predict a difficult airway which incorporate anatomic and physiologic features. While helpful, these tools should not be used in isolation. Preoxygenation and apneic oxygenation are recommended to reduce the risk of desaturation and patient decompensation, particularly with noninvasive ventilation in critically ill patients. Induction and neuromuscular blocking medications should be tailored to the clinical scenario. Video laryngoscopy is superior to direct laryngoscopy among novice users, while both techniques are reasonable among more experienced clinicians. Recent literature suggests using a bougie during the first attempt. Point-of-care ultrasound is helpful for confirming correct placement and depth of the endotracheal tube. An understanding of literature updates can improve the ED care of patients requiring emergent intubation.

Preoxygenation utilizing a non-rebreather mask (NRB) to deliver oxygen at the maximal flow rate (>50 L/min) from a standard hospital gas flowmeter (i.e., the flush rate) is an accepted technique during emergency airway management. Existing guidance to preoxygenate patients for at least 3 min is based on use of oxygen-delivery devices not commonly used in the emergency department (e.g., a closed anesthesia circuit). We sought to determine the median length of time needed to achieve adequate preoxygenation utilizing an NRB with flush rate oxygen. Healthy volunteers performing tidal breathing underwent a 5-min trial of preoxygenation with NRB mask with flush rate oxygen. End-tidal oxygen (EtO2), a measure of the degree of adequate preoxygenation, was recorded every 15 s. Adequate preoxygenation was defined as EtO2 ≥ 85 %. We enrolled 50 participants. The median maximum EtO2 achieved during preoxygenation was 87 % (interquartile range [IQR] 87–89 %) and all participants achieved an EtO2 > 80 %. The median time to reach an EtO2 of 85 % was 90 s (IQR 60–135 s). By 3 min, 86 % (95 % CI 73 % to 94 %) of participants had achieved adequate preoxygenation. In healthy participants undergoing preoxygenation with an NRB mask with flush rate oxygen, the median time to adequate preoxygenation was 90 s and 86 % were adequately preoxygenated at 3 min. This suggests that 3 min of preoxygenation is a reasonable target using this technique.

BackgroundCombining oxygen facemask with apnoeic oxygenation using high-flow-nasal-oxygen (HFNO) for preoxygenation in the operating room has not been studied against standard oxygen facemask alone. We hypothesized that facemask-alone would be associated with lower levels of lowest end-tidal oxygen (EtO2) within 2 min after intubation in comparison with facemask combined with HFNO.MethodsIn an international prospective before–after multicentre study, we included adult patients intubated in the operating room from September 2022 to December 2022. In the before period, preoxygenation was performed with facemask-alone, which was removed during laryngoscopy. In the after period, facemask combined with HFNO was used for preoxygenation and HFNO for apnoeic oxygenation during laryngoscopy. HFNO was maintained throughout intubation. The primary outcome was the lowest EtO2 within 2 min after intubation. The secondary outcome was SpO2 ≤ 95% within 2 min after intubation. Subgroup analyses were performed in patients without and with obesity. This study was registered 10 August 2022 with ClinicalTrials.gov, number NCT05495841.ResultsA total of 450 intubations were evaluated, 233 with facemask-alone and 217 with facemask combined with HFNO. In all patients, the lowest EtO2 within 2 min after intubation was significantly lower with facemask-alone than with facemask combined with HFNO, 89 (85–92)% vs 91 (88–93)%, respectively (mean difference − 2.20(− 3.21 to − 1.18), p < 0.001). In patients with obesity, similar results were found [87(82–91)% vs 90(88–92)%, p = 0.004]; as in patients without obesity [90(86–92)% vs 91(89–93)%, p = 0.001)]. SpO2 ≤ 95% was more frequent with facemask-alone (14/232, 6%) than with facemask combined with HFNO (2/215, 1%, p = 0.004). No severe adverse events were recorded.ConclusionsCombining facemask with HFNO for preoxygenation and apnoeic oxygenation was associated with increased levels of lowest EtO2 within 2 min after intubation and less desaturation.