BACKGROUND: Preoxygenation is very important to protect the patient from hypoxia before intubation. However, pulse oximetry has some limitations in detecting hypoxia.
OBJECTIVE: We aimed to compare the effectiveness of 2 preoxygenation techniques based on oxygen reserve index (ORI) levels.
METHODS: Twenty healthy male volunteers were included in the study. They inhaled 100% FiO2 oxygen administered at 5 L/min as the 1st technique (M1) with a ventilation mask as much as their tidal volumes for 3 min. The 2nd technique (M2) applied 100% FiO2 oxygen at 10 L/min flow using the same mask and 8 deep inspiratory volumes, which was aimed to be completed within 1 min. Maximum ORI levels, duration to reach that level, and time needed to reach the target ORI level (0.35) and return back to the \"0\" were measured.
RESULTS: In the M1 group, ORI levels were significantly higher during and after 60 s, according to post hoc tests. In the M2 groups, ORI levels were significantly higher during and after the 4th inspiration, according to post hoc tests. Oxygen reserve index values at the 60th 2nd (M1) and 8th inspiration (M2) were compared as the 8th inspiration corresponded to the 60th second. The maximum ORI values were significantly lower in the M1 group compared to the M2 group (p < 0.001 and p = 0.006, respectively). Seven volunteers (36.8%) in the M1 group and 2 volunteers (10.5%) in the M2 group could not reach the target ORI (McNemar\'s test, test statistic 3.2, degrees of freedom (df) = 1, p = 0.063). The time to reach the target ORI value and to reach maximum ORI values was significantly longer in the M1 group than in the M2 group (p = 0.008 and p < 0.001, respectively).
CONCLUSIONS: We observed that the 8-deep breath technique is more effective in preoxygenation compared to the 3-min tidal volume technique.

UNASSIGNED: Preoxygenation before endotracheal intubation (ETI) maintains asphyxiated oxygenation and reduces the risk of hypoxia-induced adverse events. Previous studies have compared various preoxygenation methods. However, network meta-analyses (NMAs) of the combined comparison of preoxygenation methods is still lacking.
UNASSIGNED: We searched for studies published in PubMed, Embase, Web of Science, Scopus, and the Cochrane Library. Review Manager version 5.3 was used to evaluate the risk of bias. The primary outcome of this meta-analysis was low oxygen saturation (SpO2) during ETI. The secondary outcomes included SpO2 <80%, SpO2 <90%, and apnea time during ETI. NMA was performed using R 4.1.2 software gemtc packages in RStudio.
UNASSIGNED: A total of 15 randomized controlled trials were included in this study. Regarding the lowest SpO2, the noninvasive ventilation (NIV) with high-flow nasal cannula (HFNC) group performed better than the other groups. For SpO2 <80%, the NIV group (0.8603467) performed better than the HFNC (0.1373533) and conventional oxygen therapy (COT, 0.0023) groups, according to the surface under the cumulative ranking curve results. For SpO2 <90%, the NIV group (0.60932667) performed better than the HFNC (0.37888667) and COT (0.01178667) groups. With regard to apnea time, the HFNC group was superior to the COT group (mean difference: -50.05; 95% confidence interval: -90.01, -10.09; P = 0.01).
UNASSIGNED: Network analysis revealed that NIV for preoxygenation achieved higher SpO2 levels than HFNC and COT and offered a more significant advantage in maintaining patient oxygenation during ETI. Patients experienced a longer apnea time after HFNC preoxygenation. The combination of NIV with HFNC proved to be significantly superior to other methods. Given the scarcity of such studies, further research is needed to evaluate its effectiveness.
UNASSIGNED: identifier CRD42022346013.

暂无摘要。

BACKGROUND: Preoxygenation is universally recommended before induction of general anaesthesia to prolong safe apnoea time. The optimal technique for preoxygenation is unclear. We conducted a systematic review to determine the preoxygenation technique associated with the greatest effectiveness in adult patients having general anaesthesia.
METHODS: We searched six databases for randomised controlled trials of patients aged ≥16 yr, receiving general anaesthesia in any setting and comparing different preoxygenation techniques and methods. Our primary effectiveness outcome was safe apnoea time, and secondary outcomes included incidence of arterial oxygen desaturation; lowest SpO2 during airway management; time to end-tidal oxygen concentration of 90%; and [Formula: see text] and [Formula: see text] at the end of preoxygenation. We assessed the quality of evidence according to Grading of Recommendations, Assessment, Development and Evaluation (GRADE) recommendations.
RESULTS: We included 52 studies of 3914 patients. High-flow nasal oxygen with patients in a head-up position was most likely to be associated with a prolonged safe apnoea time when compared with other strategies, with a mean difference (95% credible interval) of 291 (138-456) s and 203 (79-343) s compared with preoxygenation with a facemask in the supine and head-up positions, respectively. Subgroup analysis of studies without apnoeic oxygenation also showed high-flow nasal oxygen in the head-up position as the highest ranked technique, with a statistically significantly delayed mean difference (95% credible interval) safe apnoea time compared with facemask in supine and head-up positions of 222 (63-378) s and 139 (15-262) s, respectively. High-flow nasal oxygen was also the highest ranked technique for increased [Formula: see text] at the end of preoxygenation. However, the incidence of arterial desaturation was less likely to occur when a facemask with pressure support was used compared with other techniques, and [Formula: see text] was most likely to be lowest when preoxygenation took place with patients deep breathing in a supine position.
CONCLUSIONS: Preoxygenation of adults before induction of general anaesthesia was most effective in terms of safe apnoea time when performed with high-flow nasal oxygen with patients in the head-up position in comparison with facemask alone. Also, high-flow nasal oxygen in the head-up position is likely to be the most effective technique to prolong safe apnoea time among those evaluated. Clinicians should consider this technique and patient position in routine practice.
UNASSIGNED: PROSPERO CRD42022326046.

暂无摘要。

OBJECTIVE: Ventilator-assisted preoxygenation (VAPOX) is a method of preoxygenation and apnoeic ventilation which has been tried in hospital setting. We aimed to describe VAPOX during intubation of critically unwell patients in aeromedical retrieval setting.
METHODS: Retrospective observational study of VAPOX performed at LifeFlight Retrieval Medicine (LRM) between January 2018 and December 2022 across Queensland, Australia. Demographic and clinical data were recorded. Descriptive statistics and paired Student\'s t-tests were used to evaluate the efficacy of VAPOX on oxygen saturation (SpO2).
RESULTS: VAPOX was used in 40 patients. Diagnoses included pneumonia (n = 11), COPD (n = 6) and neurological (n = 7). Patients were intubated in hospital (n = 36), in helicopter (n = 2) and ambulance (n = 2). Median VAPOX settings were: positive end-expiratory pressure 6 (IQR 5-9), pressure support 10 (IQR 10-14) and back up respiratory rate 14 (IQR 11-18). Twelve agitated patients underwent delayed sequence induction with ketamine. There was a statistically significant increase in SpO2 after application of VAPOX (P < 0.001), followed by a slight decrease after intubation (P = 0.006). Mean SpO2 were significantly improved after intubation compared with on arrival of LRM (P = 0.016). Hypotension was present prior to VAPOX (n = 13), during VAPOX (n = 2) and post-intubation (n = 15). Two patients had cardiac arrest. Three patients were started on VAPOX but subsequently failed. There were no significant oxygen depletion or aspiration events.
CONCLUSIONS: VAPOX can be considered for pre-intubation optimisation in the retrieval environment. The incidence of post-intubation critical hypoxia was low, and hypotension was high. Pre-intubation respiratory physiology can be optimised by delivering variable pressure supported minute ventilation, achieving a low incidence of critical hypoxia.

UNASSIGNED: The 25°back-up position is proposed to increase the efficacy of preoxygenation and provide better tracheal intubating conditions when using a direct laryngoscope. This study aimed to compare the ease of tracheal intubation between supine and 25° back-up positions when using two video laryngoscopes (VLS).
UNASSIGNED: One hundred adults with normal airways and belonging to the American Society of Anesthesiologists physical status classes I and II, requiring general anaesthesia, were randomised in groups K and M. The trachea was intubated using King Vision and McGrath VLS in either supine (groups K1 and M1) or 25° back-up (groups K2 and M2) positions. The 25° backup position was given by raising the operating table from the horizontal position by flexing the torso at the hips so that an imaginary line connected the patient\'s external auditory meatus to the sternal notch. Modified Intubation Difficulty Scale (mIDS) was the primary outcome, and intubation time, the number of intubation attempts, vital parameters, and complications were compared secondarily. Statistical analysis was done using MedCalc software by applying an independent t-test for parametric data and a Chi-square test for categorical data and finding the risk ratio.
UNASSIGNED: Mean (Standard deviation) mIDS was significantly reduced using both VLS in the 25° back-up position [0.92 (0.75) versus 0.48 (0.58), P = 0.025, degree of freedom (DF): 48, mean difference (95% confidence interval [CI]):-0.44 (-0.821 to - 0.059) in group K1 versus group K2 and 0.76 (0.59) versus 0.36 (0.48), P = 0.012, DF: 48, mean difference (95% CI): -0.40(-0.706 to - 0.094) in group M1 versus group M2, respectively]. The risk ratio comparing both the positions for the total number of patients requiring manoeuvres during intubation using both the VLS was 0.48 with P = 0.0004 and 95% CI = 0.305 - 0.765. Intubation time was shorter in the 25° backup position by using King Vision (P = 0.005) and McGrath (P = 0.042) VLS.
UNASSIGNED: The 25° backup position helps provide ease of intubation using both the channelled (King Vision) and non-channelled (McGrath) VLS.

BACKGROUND: Although preoxygenation is an essential procedure for safe endotracheal intubation, in some cases securing sufficient time for tracheal intubation may not be possible. Patients with head and neck cancer might have a difficult airway and need a longer time for endotracheal intubation. We hypothesized that the extended apneic period with preoxygenation via a high-flow nasal cannula (HFNC) is beneficial to patients who undergo head and neck surgery compared with preoxygenation with a simple mask.
METHODS: The study was conducted as a single-center, single-blinded, prospective, randomized controlled trial. Patients were divided into groups based on one of the two preoxygenation.
METHODS: HFNC group or simple facemask (mask group). Preoxygenation was performed for 5 minutes with each method, and endotracheal intubation for all patients was performed using a video laryngoscope. Oxygen partial pressures of the arterial blood were compared at the predefined time points.
RESULTS: For the primary outcome, the mean arterial oxygen partial pressure (PaO2 ) immediately after intubation was 454.2 mm Hg (95% confidence interval [CI], 416.9-491.5 mm Hg) in the HFNC group and 370.7 mm Hg (95% CI, 333.7-407.4 mm Hg) in the mask group (P=0.002). The peak PaO2 at 5 minutes after preoxygenation was not statistically different between the groups (P=0.355).
CONCLUSIONS: Preoxygenation with a HFNC extending to the apneic period before endotracheal intubation may be beneficial in patients with head and neck cancer.

暂无摘要。

OBJECTIVE: Hypoxia is a frequently reported complication during the intubation procedure in the emergency department (ED) and may cause bad outcomes. Therefore, oxygenation plays an important role in emergency airway management. The efficacy of oxygenation with high-flow nasal cannula (HFNC) in the ED has been studied, though the evidence is limited. The study aim was to compare two methods of preoxygenation in patients undergoing rapid sequence intubation (RSI) in the ED: (1) HFNC and (2) bag-valve mask (BVM) oxygenation.
METHODS: This is a single-center, prospective, randomized controlled trial (RCT) in adult ED patients requiring RSI. Patients were randomized to receive preoxygenation with either HFNC or BVM. While HFNC therapy was continued during the intubation procedure, BVM oxygenation was interrupted for laryngoscopy. The primary outcome was the lowest peripheral oxygen saturation (SpO2) level during intubation. Secondary outcomes were incidence of desaturation (SpO2<90%) and severe hypoxemia (SpO2<80%) throughout the procedure, intubation time, rate of failed intubation, and 30-day survival rates.
RESULTS: A total of 135 patients were randomized into two groups (HFNC n = 68; BVM n = 67). The median lowest SpO2 value measured during intubation was 96% (88.8%-99.0%) in the HFNC group and 92% (86.0%-97.5%) in the BVM group (P = .161). During the intubation procedure, severe hypoxemia occurred in 13.2% (n = 9) of patients in the HFNC group and 8.9% (n = 6) in the BVM group, while mild hypoxemia was observed in 35.8% (n = 24) of the BVM group and 26.5% (n = 18) of the HFNC group. However, there was no statistically significant difference between the groups in terms of hypoxemia development (P = .429 and P = .241, respectively). No significant difference was reported in the rate of failed intubation between the groups. Thirty-day mortality was observed in 73.1% of the BVM group and 57.4% of the HFNC group, with a borderline statistically significant difference (difference 15.7; 95% CI of the difference: -0.4 to 30.7; P = .054).
CONCLUSIONS: The use of HFNC for preoxygenation, when compared to standard care with BVM oxygenation, did not improve the lowest SpO2 levels during intubation. Also, the use of HFNC during intubation did not provide benefits in reducing the incidence of severe hypoxemia. However, the 30-day survival rates were slightly better in the HFNC group compared to the BVM group.