Safe Apnea Research Articles

Direct versus video laryngoscopy with standard blades for neonatal and infant tracheal intubation with supplemental oxygen: a multicentre, non-inferiority, randomised controlled trial

Tracheal intubation in neonates and infants is a potentially life-saving procedure. Video laryngoscopy has been found to improve first-attempt tracheal intubation success and reduce complications compared with direct laryngoscopy in children younger than 12 months. Supplemental periprocedural oxygen might increase the likelihood of successful first-attempt intubation because of an increase in safe apnoea time. We tested the hypothesis that direct laryngoscopy is not inferior to video laryngoscopy when using standard blades and supplemental oxygen is provided. We did a non-inferiority, international, multicentre, single-blinded, randomised controlled trial, in which we randomly assigned neonates and infants aged up to 52 weeks postmenstrual age scheduled for elective tracheal intubation to either direct laryngoscopy or video laryngoscopy (1:1 ratio, randomly assigned using a secure online service) at seven tertiary paediatric hospitals across Australia, Canada, Italy, Switzerland, and the USA. An expected difficult intubation was the main exclusion criteria. Parents and patients were masked to the assigned group of treatment. All infants received supplemental oxygen (1 L/Kg per min) during laryngoscopy until the correct tracheal tube position was confirmed. The primary outcome was the proportion of first-attempt tracheal intubation success, defined as appearance of end-tidal CO2 curve at the anaesthesia monitor, between the two groups in the modified intention-to-treat analysis. A 10% non-inferiority margin between direct laryngoscopy or video laryngoscopy was applied. The trial is registered with ClinicalTrials.gov (NCT04295902) and is now concluded. Of 599 patients assessed, 250 patients were included between Oct 26, 2020, and March 11, 2022. 244 patients were included in the final modified intention-to-treat analysis. The median postmenstrual age on the day of intubation was 44·0 weeks (IQR 41·0-48·0) in the direct laryngoscopy group and 46·0 weeks (42·0-49·0) in the video laryngoscopy group, 34 (28%) were female in the direct laryngoscopy group and 38 (31%) were female in the video laryngoscopy group. First-attempt tracheal intubation success rate with no desaturation was higher with video laryngoscopy (89·3% [95% CI 83·7 to 94·8]; n=108/121) compared with direct laryngoscopy (78·9% [71·6 to 86·1]; n=97/123), with an adjusted absolute risk difference of 9·5% (0·8 to 18·1; p=0·033). The incidence of adverse events between the two groups was similar (-2·5% [95% CI -9·6 to 4·6]; p=0·490). Post-anaesthesia complications occurred seven times in six patients with no difference between the groups. Video laryngoscopy with standard blades in combination with supplemental oxygen in neonates and infants might increase the success rate of first-attempt tracheal intubation, when compared with direct laryngoscopy with supplemental oxygen. The incidence of hypoxaemia increased with the number of attempts, but was similar between video laryngoscopy and direct laryngoscopy. Video laryngoscopy with oxygen should be considered as the technique of choice when neonates and infants are intubated. Swiss Pediatric Anaesthesia Society, Swiss Society for Anaesthesia and Perioperative Medicine, Foundation for Research in Anaesthesiology and Intensive Care Medicine, Channel 7 Telethon Trust, Stan Perron Charitable Foundation, National Health and Medical Research Council.

Non-invasive ventilation for preoxygenation before general anesthesia: a systematic review and meta-analysis of randomized controlled trials

Background and objectivesPreoxygenation is crucial for providing sufficient oxygen reservoir to a patient before intubation and enables the extension of the period between breathing termination and critical desaturation (safe apnoea time). Conventionally, face mask ventilation is used for preoxygenation. Non-invasive ventilation is a new preoxygenation method. The study objective was to compare the outcomes of non-invasive ventilation and face mask ventilation for preoxygenation.MethodPubMed, Embase, Cochrane Library, and the ClinicalTrials.gov registry were searched for eligible studies published from database inception to September 2021. Individual effect sizes were standardized, and a meta-analysis was conducted using random effects models to calculate the pooled effect size. Inclusion criteria were randomised controlled trials of comparing the outcomes of non-invasive ventilation or face mask ventilation for preoxygenation in patients scheduled for surgeries. The primary outcome was safe apnea time, and the secondary outcomes were post-operative complications, number of patients who achieved the expired O2 fraction (FeO2) after 3 min of preoxygenation, minimal SpO2 during tracheal intubation, partial pressure of oxygen in the arterial blood (PaO2) and partial pressure of carbon dioxide (PaCO2) after preoxygenation, and PaO2 and PaCO2 after tracheal intubation.Results13 trials were eligible for inclusion in this study. Significant differences were observed in safe apnoea time, number of patients who achieved FeO2 90% after preoxygenation for 3 min, and PaO2 and PaCO2 after preoxygenation and tracheal intubation. Only in the non-obese subgroup, no significant difference was observed in safe apnoea time (mean difference: 125.38, 95% confidence interval: − 12.26 to 263.03).ConclusionNon-invasive ventilation appeared to be more effective than conventional methods for preoxygenation. We recommend non-invasive ventilation based on our results.

Role of modified nasopharyngeal oxygen therapy in apnoeic oxygenation under general anaesthesia: a single-centre, randomized controlled clinical study

Apnoeic oxygenation is not only important for patients who cannot be intubated/ventilated, but also can be routinely employed when planning to secure the airway.We aimed to compare safe apnoea times between patients receiving modified nasopharyngeal oxygen therapy and those receiving high-flow nasal oxygen therapy (HFNO) following the induction of general anaesthesia.This was a single-centre, randomized controlled clinical study. Eighty-four female patients undergoing elective laparoscopic gynaecological surgery under general anaesthesia were randomly assigned to the high-flow nasal oxygen therapy group (Group HFNO) or the modified nasopharyngeal oxygen therapy group (Group Naso). A Kaplan–Meier survival curve was used to describe the apnoeic oxygenation time.The safe apnoea time of the patients in the Group Naso was higher than that of the patients in the Group HFNO (20 (19.3 to 20.0) vs. 16.5 (12.9 to 20) minutes, P < 0.05). The incidence of SpO2 < 95% in the Group Naso was lower than that in the Group HFNO; hazard ratio 0.3 (95% confidence interval 0.2 to 0.6, P < 0.0001). Modified nasopharyngeal oxygen therapy which uses far less oxygen than HFNO is a convenient and effective method of apnoeic oxygenation in normal female patients.Trial registration: https://www.chictr.org.cn, ChiCTR2000039433; date of registration: 28/10/2020.

Comparison of apnoeic oxygen techniques in term pregnant subjects: a computational modelling study

BackgroundHypoxaemia during general anaesthesia can cause harm. Apnoeic oxygenation extends safe apnoea time, reducing risk during airway management. We hypothesised that low-flow nasal oxygenation (LFNO) would extend safe apnoea time similarly to high-flow nasal oxygenation (HFNO), whilst allowing face-mask preoxygenation and rescue. MethodsA high-fidelity, computational, physiological model was used to examine the progression of hypoxaemia during apnoea in virtual models of pregnant women in and out of labour, with BMI of 24–50 kg m−2. Subjects were preoxygenated with oxygen 100% to reach end-tidal oxygen fraction (FE'O2) of 60%, 70%, 80%, or 90%. When apnoea started, HFNO or LFNO was commenced. To simulate varying degrees of effectiveness of LFNO, periglottic oxygen fraction (FgO2) of 21%, 60%, or 100% was configured. HFNO provided FgO2 100% and oscillating positive pharyngeal pressure. ResultsApplication of LFNO (FgO2 100%) after optimal preoxygenation (FE'O2 90%) resulted in similar or longer safe apnoea times than HFNO FE'O2 80% in all subjects in labour. For BMI of 24, the time to reach SaO2 90% with LFNO was 25.4 min (FE'O2 90%/FgO2 100%) vs 25.4 min with HFNO (FE'O2 80%). For BMI of 50, the time was 9.9 min with LFNO (FE'O2 90%/FgO2 100%) vs 4.3 min with HFNO (FE'O2 80%). A similar finding was seen in subjects with BMI ≥40 kg m−2 not in labour. ConclusionsThere is likely to be clinical benefit to using LFNO, given that LFNO and HFNO extend safe apnoea time similarly, particularly when BMI ≥40 kg m−2. Additional benefits to LFNO include the facilitation of rescue face-mask ventilation and ability to monitor FE'O2 during preoxygenation.

THRIVE: a different approach in microlaryngeal surgeries

&lt;p&gt;Microlaryngeal surgeries (MLS) are typically performed under general anaesthesia either by employing a microlaryngeal tube or without endotracheal intubation using high frequency jet ventilation. Recently, trans-nasal humidified rapid insufflation ventilatory exchange (THRIVE) without ET tube can be used. It has no compromised view/ access as in MLS tube and no barotrauma/movement of vocal cords/ tumour implantation as in jet ventilation. We aimed to assess the feasibility and safety of tubeless MLS using THRIVE. From December 2019 to December 2020, all the patients undergoing tubeless MLS were included. Anaesthesia was conducted with target controlled propofol infusion and muscle relaxation with THRIVE oxygen support. Perioperative data was collected and analysed. A total of 21 patients underwent MLS using THRIVE as the sole method of ventilation. Mean age was 52.6 (±13.77) years, and mean body mass index (BMI) was 25.63 (±4.91) kg/m&lt;sup&gt;2&lt;/sup&gt;. The surgical indications were vocal cord tumor/ biopsy and vocal polyp/cyst excision. Mean apnoea time was 27 min. At the end of surgery, mean end tidal CO&lt;sub&gt;2&lt;/sub&gt; was 66 mmHg. Surgeon’s satisfaction about the operating field was recorded and he rated it as either excellent (70%) or good (30%). In carefully selected patients, a combination of THRIVE and TIVA offers a good alternative to conventional anaesthesia with tubes. Our study demonstrated a considerable safe apnoea time with an acceptable CO&lt;sub&gt;2&lt;/sub&gt; build up. Surgeon acceptance of the technique was extremely promising and the operating conditions were highly rated by them.&lt;/p&gt;

Apneic oxygenation in pediatric anesthesia.

Apneic oxygenation is increasingly used in pediatric anesthesia. Its benefit for specific applications depends on the effect of apneic oxygenation on safe apnea time and carbon dioxide (CO2) elimination, on differences between low and high flow oxygen delivery, and on possible adverse effects. The present review summarizes current evidence on these pathophysiological aspects of apneic oxygenation as well as its applications in pediatric anesthesia. Apneic oxygenation with both low flow and high flow nasal oxygen increases the safe apnea time, but does not lead to increased CO2 elimination. Airway pressures and adverse effects like atelectasis formation, oxidative stress and aerosol generation under apneic oxygenation are not well studied in pediatric anesthesia. Data from adults suggest no important effect on airway pressures when the mouth is open, and no significant formation of atelectasis, oxidative stress or aerosol generation with high flow nasal oxygen. Apneic oxygenation in pediatric anesthesia is mainly used during standard and difficult airway management. It is sometimes used for airway interventions, but CO2 accumulation remains a major limiting factor in this setting. Reports highlight the use of high flow nasal oxygen in spontaneously breathing rather than in apneic children for airway interventions.

Causes of Suboptimal Preoxygenation Before Tracheal Intubation in Elective and Emergency Abdominal Surgery

Abstract Optimal preoxygenation (PO) prior to tracheal intubation reduces the risk of arterial desaturation and prolongs the period of safe apnoea. The common methods of PO are mask ventilation with 100% O2 for 3–5 minutes or, alternatively, asking the patient to take eight deep breaths in a minute. Our study group conducted a prospective study to assess the impact of the most common risk factors on PO and to compare the efficiency of PO in patients undergoing elective and emergency abdominal surgery without premedication. PO was performed using mask ventilation with 6 l/min of 100% oxygen for 5 minutes. End-tidal oxygen (EtO2) was documented in 30-second increments. We found that optimal PO (EtO2 &gt; 90%) was not achieved by almost half of the patients (46%) and that this was more common in the elective surgery group. Effective PO was not impacted by any of the evaluated risk factors for suboptimal oxygenation. Despite these findings, we believe that the identification of potential risk factors is crucial in the pre-anaesthesia stage, given the benefits of optimal PO.

Efficacy of high-flow nasal oxygenation against peri- and post-procedural hypoxemia in patients with obesity: a meta-analysis of randomized controlled trials

This meta-analysis aimed at investigating the efficacy of high-flow nasal oxygenation (HFNO) against hypoxemia in patients with obesity compared with conventional oxygenation therapy and non-invasive ventilation. Databases were searched from inception to August 2021. Studies involving peri- or post-procedural use of HFNO were included. The primary outcome was risk of hypoxemia, while the secondary outcomes included status of oxygenation and carbon dioxide elimination. Ten randomized controlled trials (RCTs) were included. We found that HFNO prolonged the safe apnea time at induction compared to control group [mean difference (MD) = 73.88 s, p = 0.0004; 2 RCTs] with no difference in risk of peri-procedural hypoxemia [relative risk (RR) = 0.91, p = 0.64; 4 RCTs], minimum SpO2 (MD = 0.09%, p = 0.95; 4 RCTs), PaO2 (MD = − 8.13 mmHg, p = 0.86; 3 RCTs), PaCO2 (MD = − 6.71%, p = 0.2; 2 RCTs), EtCO2 (MD = − 0.28 mmHg, p = 0.8; 4 RCTs) between the two groups. HFNO also did not improve postprocedural PaO2/FiO2 ratio (MD = 41.76, p = 0.58; 2 RCTs) and PaCO2 (MD = − 2.68 mmHg, p = 0.07; 2 RCTs). This meta-analysis demonstrated that the use of HFNO may be associated with a longer safe apnea time without beneficial impact on the risk of hypoxemia, oxygenation, and CO2 elimination in patients with obesity. The limited number of trials warranted further large-scale studies to support our findings.

Comparison of the effectiveness of high-flow nasal oxygen vs. standard facemask oxygenation for pre- and apneic oxygenation during anesthesia induction: a systematic review and meta-analysis

BackgroundIn recent years, high flow nasal oxygen (HFNO) has been widely used in clinic, especially in perioperative period. Many studies have discussed the role of HFNO in pre- and apneic oxygenation, but their results are controversial. Our study aimed to examine the effectiveness of HFNO in pre- and apneic oxygenation by a meta-analysis of RCTs.MethodsEMBASE, PUBMED, and COCHRANE LIBRARY databases were searched from inception to July 2021 for relevant randomized controlled trails (RCTs) on the effectiveness of HFNO versus standard facemask ventilation (FMV) in pre- and apenic oxygenation. Studies involving one of the following six indicators: (1) Arterial oxygen partial pressure (PaO2), (2) End expiratory oxygen concentration (EtO2), (3) Safe apnoea time, (4) Minimum pulse oxygen saturation (SpO2min), (5) Oxygenation (O2) desaturation, (6) End expiratory carbon dioxide (EtCO2) or Arterial carbon dioxide partial pressure(PaCO2) were included. Due to the source of clinical heterogeneity in the observed indicators in this study, we adopt random-effects model for analysis, and express it as the mean difference (MD) or risk ratio (RR) with a confidence interval of 95% (95%CI). We conducted a risk assessment of bias for eligible studies and assessed the overall quality of evidence for each outcome.ResultsFourteen RCTs and 1012 participants were finally included. We found the PaO2 was higher in HFNO group than FMV group with a MD (95% CI) of 57.38 mmHg (25.65 to 89.10; p = 0.0004) after preoxygenation and the safe apnoea time was significantly longer with a MD (95% CI) of 86.93 s (44.35 to 129.51; p < 0.0001) during anesthesia induction. There were no significant statistical difference in the minimum SpO2, CO2 accumulation, EtO2 and O2 desaturation rate during anesthesia induction between the two groups.ConclusionsThis systematic review and meta-analysis suggests that HFNO should be considered as an oxygenation tool for patients during anesthesia induction. Compared with FMV, continuous use of HFNO during anesthesia induction can significantly improve oxygenation and prolong safe apnoea time in surgical patients.

Pre- and apnoeic high-flow oxygenation for rapid sequence intubation in the emergency department (the Pre-AeRATE trial): A multicentre randomised controlled trial

Evidence regarding the efficacy of high-flow nasal cannula (HFNC) oxygenation for preoxygenation and apnoeic oxygenation is conflicting. Our objective is to evaluate whether HFNC oxygenation for preoxygenation and apnoeic oxygenation maintains higher oxygen saturation (SpO2) during rapid sequence intubation (RSI) in ED patients compared to usual care. This was a multicentre, open-label, randomised controlled trial in adult ED patients requiring RSI. Patients were randomly assigned 1:1 to either intervention (HFNC oxygenation at 60L/min) group or control (non-rebreather mask for preoxygenation and nasal prongs of at least 15L/min oxygen flow for apnoeic oxygenation) group. Primary outcome was lowest SpO2 during the first intubation attempt. Secondary outcomes included incidence of SpO2 falling below 90% and safe apnoea time. One hundred and ninety patients were included, with 97 in the intervention and 93 in the control group. Median lowest SpO2 during the first intubation attempt was 100% in both groups. Incidence of SpO2 falling below 90% was lower in the intervention group (15.5%) compared to the control group (22.6%) (adjusted relative risk=0.68, 95% confidence interval [CI] 0.37-1.25). Post hoc quantile regression analysis showed that the first quartile of lowest SpO2 during the first intubation attempt was greater by 5.46% (95% CI 1.48-9.45%, P=0.007) in the intervention group. Use of HFNC for preoxygenation and apnoeic oxygenation, when compared to usual care, did not improve lowest SpO2 during the first intubation attempt but may prolong safe apnoea time.

A comparison of high-flow nasal cannula and standard facemask as pre-oxygenation technique for general anesthesia: A PRISMA-compliant systemic review and meta-analysis.

Background:Current practice guidelines recommend the use of nasal cannula as an alternative pre-oxygenation method for tracheal intubation. However, the efficacy of high-flow nasal oxygenation versus standard facemask oxygenation has not been fully evaluated.Methods:We searched PubMed, Cochrane Library, and ClinicalTrials.gov for English-language studies published from January 1, 2000 to November 30, 2021. We included randomized controlled trials which compared high-flow nasal oxygenation and facemask oxygenation as the pre-oxygenation maneuver. Primary outcome was arterial partial pressure of oxygen (PaO2) after pre-oxygenation. Secondary outcomes were safe apnea time, arterial desaturation during intubation, lowest peripheral capillary oxygen saturation during intubation, and patient comfort score. Random-effects models and Mantel–Haenszel method were used for data synthesis.Results:A total of 16 randomized controlled trials and 1148 patients were included. High-flow nasal oxygenation achieved a higher PaO2 compared with facemask, mean difference: 64.86 mm Hg (95% confidence interval [CI]: 32.33–97.40, P < .0001). Safe apnea time was longer in high-flow nasal oxygenation, mean difference: 131.03 seconds (95% CI: 59.39–202.66, P < .0001). There was no difference in the risk of peri-intubation desaturation or lowest peripheral capillary oxygen saturation between groups. Patient comfort score was higher in high-flow nasal oxygenation, mean difference: 1.00 (95% CI: 0.46–1.54, P = .0003).Conclusion:High-flow nasal oxygenation better enhanced PaO2 and extended safe apnea time and is not inferior to facemask oxygenation in preventing desaturation during tracheal intubation. High-flow nasal oxygenation may be considered as an alternative method, especially for patients with a potential difficult airway.

Advances in airway management during the induction of anesthesia: a narrative review

Background and Objective: This review summarizes the new techniques and devices available including high-flow nasal oxygen (HFNO) therapy, apnoeic oxygenation, video laryngeal mask, video laryngoscope (VL), flexible tip bougie (FTB), novel drugs, and artificial intelligence (AI) in airway management during the induction of anesthesia. Airway management during the induction of anesthesia is crucial and has progressed considerably in the past decade. Preoxygenation can improve oxygen reserves and extend the safe apnea time. Recently, preoxygenation via HFNO was introduced with significant success. The role of apneic oxygenation is also increasingly recognized. The combination of visualization and traditional intubation equipment has become the method of choice for anesthesiologists. Tracheal tube introducers are devices that can successfully aid airway management, especially in the difficult airway. The design and shape of these devices are constantly evolving to optimize intubation. Anesthetic are constantly updated to ensure the safety and efficiency. Remimazolam is a recently approved anesthetic. Remifentanil and dexmedetomidine are ideal drugs recommend in recently released Guidelines for Awake Tracheal Intubation (ATI) in Adults. The role of succinylcholine remains controversial and whether it can be replaced by rocuronium completely has triggered lots of researches. Finally, AI is a hot topic in medicine and it has been recently applied in airway management.

Effect of Variable Preoxygenation Endpoints on Safe Apnea Time Using High-flow Nasal Oxygen for Women in Labor: A Modeling Investigation

(Br J Anaesth. 2021;126:889e895) When using general anesthesia in pregnant patients, achieving an adequate safe apnea time is important. High-flow, humidified, nasal oxygen (HFNO) through a nasal cannula can provide convenient apneic oxygen supplementation, but there is a lack of studies on this practice in obstetrics and some studies have shown HFNO is not as effective as tight-fitting facemask oxygenation in pregnant patients. While HFNO may result in a lower FE’O2, this study hypothesizes that apneic oxygenation with HFNO will provide a longer safe apnea period than facemask techniques in obstetric patients.

Effectiveness of preoxygenation during endotracheal intubation in ahead-elevated position: asystematic review and meta-analysis of randomized controlled trials.

Preoxygenation during endotracheal intubation is important to ensure the safety of the procedure. This systematic review and meta-analysis aimed to evaluate the efficacy of preoxygenation in the head-elevated position as compared to the supine position. The Medline, PubMed, Scopus, Embase, and CENTRAL databases were searched systematically from inception of the study until 29 June 2021. Only randomized controlled trials (RCTs) were included. The Cochrane Risk of Bias Assessment Tool and GRADE assessment of certainty of evidence were used. Seven RCTs (n = 508) were analysed, of which 6 were included in the meta-analysis (n = 227). Six studies were carried out in the operating theatre (OT), while one was performed in the critical care (ICU) setting. Compared to the supine position, the head-elevated position significantly increased the duration of the safe apnoea period (mean difference 61.99 s; 95% confidence interval 42.93-81.05 s; P < 0.00001; I2 = 30%; certainty of evidence = high). This improvement was seen in both the obese and non-obese population (I2 = 0%). No differences were seen between both groups with regard to recovery time after apnoea, arterial oxygen tension after preoxygenation, and the incidence of adverse events. In the ICU setting, no difference was found between groups for the incidence of hypoxaemia and the lowest oxygen saturation between induction and after intubation. This meta-analysis demonstrated that the head-elevated position significantly improved the efficacy of preoxygenation during elective intubation in the OT. Clinicians should consider the head-elevated position as astarting intubating position for all patients undergoing anaesthesia in view of its many benefits and the lack of proven adverse consequences. Protocol Registration: This systematic review was registered prospectively in PROSPERO (CRD42019128962).

The effect of transnasal humidified rapid-insufflation ventilator exchange (THRIVE) versus nasal prongs on safe apnoea time in paralysed obese patients: a randomised controlled trial

BackgroundEvidence is lacking regarding the efficacy of Optiflow transnasal humidified rapid-insufflation ventilator exchange (THRIVE™) in obese patients. We compared the impact of this technique at 70 L min−1 with 4 L min−1 oxygen via nasal prongs on safe apnoea times of paralysed obese patients. MethodsWe randomised adults with a BMI >35 kg m−2 undergoing elective bariatric surgery. While apnoeic and paralysed, Group T received 70 L min−1 oxygen via Optiflow THRIVE™. Group N received nasal prong oxygen at 4 L min−1. The primary outcome was time to SpO2 ≤95% while apnoeic, with a 360 s cut-off. This was analysed by applying a time-to-event analysis. ResultsForty-two patients were included. The median (inter-quartile range) BMI was 44.8 kg m−2 (40.0–50.0) in Group T and 42.0 kg m−2 (39.3–45.1) in Group N. Median (inter-quartile range) time to SpO2 ≤95% in Group T was 356 (165 to ≥360) s and in Group N, 210 (160–270) s. Using a survival analysis framework, median time-to-event in Group T was 356 s (95% confidence interval 165 s–upper limit not defined) and 210 s (95% confidence interval 160–242 s) (P=0.049) in Group N. ConclusionsCompared with oxygen delivered via nasal prongs at 4 L min−1, oxygen delivery via Optiflow THRIVE™ at a flow rate of 70 L min−1 can prolong safe apnoea time, however, the results are statistically inconclusive. Optiflow THRIVE™ did decrease the rate of reduction in Pao2 during apnoea. Clinical trial registrationANZCTR 12618000445279.

Use of high flow oxygen (HFO) for difficult airway management in Jael syndrome: a case report

: Jael Syndrome is defined as an intentional craniofacial stab injury. There are few cases in the medical literature describing such facial impalements with the presence of the instrument in the face. Such cases present a complex challenge, involving many specialities, and in particular requires cautious considerations in the immediate preoperative management and intubation of such patients. The use of High Flow Oxygen (HFO) has an increasingly popular role in anaesthetic and intensive care practices, with numerous studies supporting its efficacy in preoxygenation and increasing the safe apnoea time prior to intubation. We report the case of a 20 years old man who presented with facial impalement with a kitchen knife following an altercation. Imaging confirmed that the knife passed through the nasopharynx and was embedded in his right occipital condyle. He was transferred to theatre, where prior to the removal of the implement and haemostasis control, he was preoxygenated using (HFO) and his airway secured with video laryngoscopy. Post operatively, he was kept sedated and ventilation in the Intensive Care Unit (ICU) prior to being successfully extubated and transferred to the ward. He was subsequently discharged form hospital with only mild sensory loss secondary to the injury. This case highlights the technical difficulties associated with the preoxygenation and intubation in patients presenting with facial impalement, and in particular use of HFO in providing for an extended safe apnoea time prior to securing a difficult airway in the context of maxillofacial trauma.

Apnoeic Oxygenation during Simulated Difficult Intubation in Obese Patients: Comparison of Buccal Ring, Adair and Elwyn Tube Versus Nasal Cannula: A Prospective Randomized Controlled Trial.

Background:Apnoeic oxygenation is an established method of increasing safe apnoea times during intubation and this is of more importance in obese patients. The usefulness of buccal Ring, Adair and Elwyn (RAE) oxygenation has been established in previous studies, however a head-to-head comparison with nasal cannula (NC) is lacking.Aim:The aim of this study was to compare apnoea time with buccal RAE (BR) versus NC in obese patients.Setting and Design:This was a prospective, nonblinded randomized controlled trial conducted in a tertiary hospital where fifty American Society of Anaesthesiologists Physical Status Class I and II, obese patients with body mass index ≥30, posted for elective surgery were included.Materials and Methods:Following adequate preoxygenation and standard induction of anaesthesia, a prolonged simulated difficult laryngoscopy was performed during which oxygen was provided via either BR or NC. The primary outcome was time to desaturation to <95% or 10 min, which ever occurred first. Other outcomes recorded were lowest saturation, time to resaturation and highest end tidal carbon di oxide.Statistical Analysis:Mean with standard deviation (SD) or median with inter quartile range were used for continuous variables and absolute number with percentage were used for categorical variables. The primary outcome was analyzed using Kaplan-Meier survival curves, and log-rank tests were applied.Results:Patient characteristics were similar in both arms. The mean apnoea time in seconds (SD) in the BR group, 375.3 (116.6) was higher than the NC group 316.1 (94.1), P = 0.054. From the Kapan Meier curves the probability of desaturating to <95% was earlier in the NC group than the BR group (P = 0.092). The other outcomes were similar in both groups.Conclusion:This is the first study that demonstrates that oxygenation via a BR is better than NC in providing apnoeic oxygenation in obese patients and can safely be used when NC are contraindicated.

Неинвазивная респираторная CPAP-подготовка пациентов с ожирением перед лапароскопическими операциями

В данной статье на основе проведенного клинического исследования описана возможность применения непродолжительной неинвазивной предоперационной CPAP-подготовки пациентов с ожирением перед индукцией в общую анестезию. В исследование были включены 16 пациентов со II степенью ожирения (индекс массы тела — 35,0–39,9 кг/м2), которые были распределены на 2 группы (контрольную и основную). Исследование было разделено на 3 основных этапа: респираторной подготовки, определения основных показателей респираторной системы и определения времени безопасного апноэ (ВБА). В контрольной группе пациентов респираторная подготовка проводилась с помощью традиционной лицевой маски и без использования положительного давления конца выдоха (PEEP) в течение 5–10 мин. В основной группе до начала индукции пациентам проводилась неинвазивная CPAP-подготовка (PEEP = 6–8 см H2O) с использованием орофациальной маски в течение такого же времени. Важным этапом исследования было определение времени безопасного апноэ у пациентов и влияния различных видов респираторной подготовки на данный важный показатель. Кроме того, были проанализированы основные показатели респираторных свойств легких (статический тораколегочный комплайенс (CRS) и общее сопротивление дыхательных путей (RAW)) при начале инвазивной искусственной вентиляции легких. Полученные результаты свидетельствуют о преимуществе использования непродолжительной неинвазивной CPAP-подготовки пациентов. В основной группе респираторные показатели были лучше, а ВБА — длительным (контрольная группа: ВБА — 213 ± 16 с, CRS — 47 мл/мм H2O, RAW — 16,75 см H2O/л в 1 с; основная группа: ВБА — 252 ± 15 с, CRS — 56 мл/мм H2O, RAW — 16,5 см H2O/л в 1 с). Анестезиологу необходимо использовать возможности современных аппаратов искусственной вентиляции легких не только в условиях палаты интенсивной терапии, но и на всех этапах периоперационного маршрута пациента. Это может уберечь от нежелательных проблем и осложнений.

High flow nasal cannula oxygen preventing deoxygenation during induction of general anaesthesia in caesarean section: A randomized controlled trial

BackgroundRecently high flow nasal oxygenation was used to prolong the safe apnoea period during induction of general anaesthesia. This randomized study was designed to compare between using transnasal humidified rapid insufflation ventilator exchange technique (THRIVE) and traditional face mask for preoxygenation in caesarean section. The primary aim was to measure the safe apnoea time. MethodsThe study was performed on 100 ASA II pregnant women scheduled for elective caesarean section under general anaesthesia. Patients were randomly assigned to either face mask ventilation or THRIVE. ResultsThe safe apnoea time was significantly longer under THRIVE with median of 7 min compared to facemask ventilation with 4 min. PaO2 with the facemask was 101 mmHg (74–215, median and range) after 3 min of apnoea vs. 355 mmHg (120–498) with THRIVE (P < 0.01). No statistically significant difference was found for PaCO2 between the two groups. ConclusionHigh humidified nasal flow oxygenation is more effective and practicable than face mask ventilation in improving oxygenation during induction of anaesthesia during caesarean section and might improve patients’ safety by avoiding desaturation.

O.2 A comparison of apnoeic oxygenation techniques in the obstetric population: A modelling investigation

Introduction: Desaturation during obstetric GA can cause fetal and neonatal harm. Apnoeic oxygenation extends safe apnoea time and published techniques include high-flow nasal oxygen (HFNO) and low-flow nasal oxygen (LFNO) via standard nasal cannulae. Whilst HFNO achieves lower FEO2 after pre- oxygenation compared to a facemask technique, [1] Shippam W. Preston R. Douglas J. et al. High-flow nasal oxygen vs. standard flow-rate facemask pre-oxygenation in pregnant patients: a randomised physiological study. Anaesthesia. 2019; 74: 450-456 Crossref PubMed Scopus (28) Google Scholar using HFNO still extends safe apnoea time. [2] Stolady D, Laviola M, Pillai A, Hardman J. The effect of variable pre-oxygenation endpoints on safe apnoea time using high flow nasal oxygen in comparison to standard facemask technique in pregnancy: a modelling investigation. Br J Anaesth in press.https://doi.org/10.1016/j.bja.2020.12.031. Google Scholar HFNO requires specialist equipment and rescue bag mask ventilation is difficult to perform. We hypothesised that LFNO would prolong safe apnoea time, when compared to HFNO, whilst allowing optimal facemask pre-oxygenation and easier rescue ventilation.