Physical and Physiological Predictors Determining the Maximal Static Apnea Diving Time of Male Freedivers.

This study aimed to investigate what factors determine freedivers' maximal static apnea dive time. We correlated some physical/physiological factors with male freedivers' maximum apnea diving duration. Thirty-six experienced male freedivers participated in this study. The divers participated in two days of the experiments. On the first day, apnea diving time, blood oxygen saturation (SpO2), heart rate (HR), blood pressure (BP), stress index, and blood parameters were measured before, during, and after the apnea diving in the pool. On the second day, body composition, lung capacity, resting and maximal oxygen consumption (VO2max), and the Wingate anaerobic power were measured in the laboratory. The data were analyzed with Pearson's Correlation using the SPSS 22 program. The correlation coefficient (R) of determination was set at 0.4, and the level of significance was set at p <0.05. There were positive correlations of diving experience, maximum SpO2, and lung capacity with the maximum apnea time R>0.4, P<0.05). There were negative correlations of BMI, body fat percentage, body fat mass, minimum SpO2, stress index, and total cholesterol with the maximum apnea diving time (R>-0.4, P<0.05). No correlations of age, height, weight, fat-free mass, skeletal muscle mass, HR, BP, blood glucose, beta- hydroxybutyrate, lactate, and hemoglobin levels with the maximum apnea diving time were observed (R<0.4, P>0.05). It is concluded that more experience in freediving, reduced body fat, extended SpO2 range, and increased lung capacity are the performance predictors and beneficial for freedivers to improve their maximum apnea diving performance.

Exerted force on the face mask in preterm infants at birth is associated with apnoea and bradycardia.

BACKGROUND: During stabilisation of preterm infants at birth, a face mask is used to provide respiratory support. However, application of these masks may activate cutaneous stretch receptors of the trigeminal nerve, causing apnoea and bradycardia. This study investigated the amount of force exerted on the face mask during non-invasive ventilation of preterm infants at birth and whether the amount of exerted force is associated with apnoea and bradycardia. METHODS: A prospective observational study was performed in preterm infants born <32 weeks of gestation who were stabilised at birth. During the first 10 minutes of respiratory support, we measured breathing and heart rate as well as the amount of force exerted on a face mask using a custom-made pressure sensor placed on top of the face mask. RESULTS: Thirty infants were included (median (IQR) gestational age(GA) 28+3 (27+0-30+0) weeks, birthweight 1104 (878-1275) grams). The median exerted force measured was 297 (198-377) grams, ranging from 0 to 1455 grams. Significantly more force was exerted on the face mask during positive pressure ventilation when compared to CPAP (410 (256-556) vs 286 (190-373) grams, p = 0.009). In a binary logistic regression model, higher forces were associated with an increased risk of apnoea (OR = 1.607 (1.556-1.661), p < 0.001) and bradycardia (OR = 1.140 (1.102-1.180), p < 0.001) during the first 10 minutes of respiratory support at birth. CONCLUSION: During mask ventilation, the median exerted force on a face mask was 297 grams with a maximum of 1455 grams. Higher exerted forces were associated apnoea and bradycardia during the first 10 minutes of respiratory support at birth.

Positioning for lumbar puncture in newborn infants.

BACKGROUND: Lumbar puncture is a common invasive procedure performed in newborns for diagnostic and therapeutic purposes. Approximately one in two lumbar punctures fail, resulting in both short- and long-term negative consequences for the clinical management of patients. The most common positions used to perform lumbar puncture are the lateral decubitus and sitting position, and each can impact the success rate and safety of the procedure. However, it is uncertain which position best improves patient outcomes. OBJECTIVES: To assess the benefits and harms of the lateral decubitus, sitting, and prone positions for lumbar puncture in newborn infants. SEARCH METHODS: We used standard, extensive Cochrane search methods. The latest search date was 24 January 2023. SELECTION CRITERIA: We included randomized controlled trials (RCTs) and quasi-RCTs involving newborn infants of postmenstrual age up to 46 weeks and 0 days, undergoing lumbar puncture for any indication, comparing different positions (i.e. lateral decubitus, sitting, and prone position) during the procedure. DATA COLLECTION AND ANALYSIS: We used standard Cochrane methods. We used the fixed-effect model with risk ratio (RR) and risk difference (RD) for dichotomous data and mean difference (MD) and standardized mean difference (SMD) for continuous data, with their 95% confidence intervals (CI). Our primary outcomes were successful lumbar puncture procedure at the first attempt; total number of lumbar puncture attempts; and episodes of bradycardia. We used GRADE to assess the certainty of evidence for each outcome. MAIN RESULTS: We included five studies with 1476 participants. Compared to sitting position: lateral decubitus position probably results in little to no difference in successful lumbar puncture procedure at the first attempt (RR 0.99, 95% CI 0.88 to 1.12; RD 0.00, 95% CI -0.06 to 0.05; I2 = 47% and 46% for RR and RD, respectively; 2 studies, 1249 infants, low-certainty evidence). None of the studies reported the total number of lumbar puncture attempts as specified in this review. Lateral decubitus position likely increases episodes of bradycardia (RR 1.72, 95% CI 1.08 to 2.76; RD 0.03, 95% CI 0.00 to 0.05; number needed to treat for an additional harmful outcome (NNTH) = 33; I2 = not applicable and 69% for RR and RD, respectively; 3 studies, 1279 infants, moderate-certainty evidence) and oxygen desaturation (RR 2.10, 95% CI 1.42 to 3.08; RD 0.06, 95% CI 0.03 to 0.09; NNTH = 17; I2 = not applicable and 96% for RR and RD, respectively; 2 studies, 1249 infants, moderate-certainty evidence). Lateral decubitus position results in little to no difference in time to perform the lumbar puncture compared to sitting position (I2 = not applicable; 2 studies; 1102 infants; high-certainty evidence; in one of the study median and IQR to report time to perform the lumbar puncture were 8 (5-13) and 8 (5-12) in the lateral and sitting position, respectively, I2 = not applicable; 1 study, 1082 infants; in the other study: mean difference 2.00, 95% CI -4.98 to 8.98; I2 = not applicable; 1 study, 20 infants). Lateral decubitus position may result in little to no difference in the number of episodes of apnea during the procedure (RR not estimable; RD 0.00, 95% CI -0.03 to 0.03; I2 = not applicable and 0% for RR and RD, respectively; 2 studies, 197 infants, low-certainty evidence). No studies reported apnea defined as number of infants with one or more episodes during the procedure. Compared to prone position: lateral decubitus position may reduce successful lumbar puncture procedure at first attempt (RR 0.75, 95% CI 0.63 to 0.90; RD -0.21, 95% CI -0.34 to -0.09; number needed to treat for an additional beneficial outcome = 5; I2 = not applicable; 1 study, 171 infants, low-certainty evidence). None of the studies reported the total number of lumbar puncture attempts or episodes of apnea. Pain intensity during and after the procedure was reported using a non-validated pain scale. None of the studies comparing lateral decubitus versus prone position reported the other critical outcomes of this review. AUTHORS' CONCLUSIONS: When compared to sitting position, lateral decubitus position probably results in little to no difference in successful lumbar puncture procedure at first attempt. None of the included studies reported the total number of lumbar puncture attempts as specified in this review. Furthermore, infants in a sitting position likely experience less episodes of bradycardia and oxygen desaturation than in the lateral decubitus, and there may be little to no difference in episodes of apnea. Lateral decubitus position results in little to no difference in time to perform the lumbar puncture compared to sitting position. Pain intensity during and after the procedure was reported using a pain scale that was not included in our prespecified tools for pain assessment due to its high risk of bias. Most study participants were term newborns, thereby limiting the applicability of these results to preterm babies. When compared to prone position, lateral decubitus position may reduce successful lumbar puncture procedure at first attempt. Only one study reported on this comparison and did not evaluate adverse effects. Further research exploring harms and benefits and the effect on patients' pain experience of different positions during lumbar puncture using validated pain scoring tool may increase the level of confidence in our conclusions.

Frequent Apnea Attacks in a 1-Month-old Infant With Influenza C Virus Infection.

Influenza C virus infection is a common and mild disease in children. Nevertheless, it remains an under-recognized cause of acute respiratory illnesses. Herein, we report the case of a 54-day-old infant who developed an influenza C virus infection and frequent apnea attacks, which could be a risk factor for sudden death and has never been reported earlier.

Apnea or cyanosis as COVID-19 initial presentation in newborns.

INTRODUCTION: The clinical manifestation of coronavirus disease 2019 (COVID-19) infection in newborns varies from asymptomatic infection to severe illness. Apnea or cyanosis as the earliest symptoms is rarely mentioned. The aim of this study is to describe the characteristics of newborns with COVID-19 infection admitted to the neonatal intensive care unit considering cyanosis or apnea as a form of presentation. METHODOLOGY: This is a descriptive observational study with retrospectively collected data. All neonates under 30 days old and preterm infants with corrected gestational age of 44 weeks who had confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection with a positive antigen or reverse transcriptase polymerase chain reaction (RT-PCR) test and who were attended to between March 2020 and March 2022 were included. RESULTS: During the two years of the study, 410 patients were admitted to the neonatal unit. Twenty-six patients (6.3%) presented with confirmed SARS-CoV-2 infection. The main clinical characteristic at admission was apnea in 55% and cyanosis in 45%. Of the 11 patients admitted with this presentation, eight were diagnosed with COVID-19 acute upper respiratory disease, and three met the definition of COVID-19 bronchiolitis. A large proportion of the patients had a mild infection (65%, n = 17), 31% (n = 8) had a severe infection and only one patient had a critical infection, accounting for 4%. CONCLUSIONS: Apnea and cyanosis can be a manifestation of SARS-CoV-2 infection in newborns, which suggests the need to include it in the diagnostic workup as other viral respiratory infections.

Positioning for lumbar puncture in newborn infants.

BACKGROUND: Lumbar puncture is a common invasive procedure performed in newborns for diagnostic and therapeutic purposes. Approximately one in two lumbar punctures fail, resulting in both short- and long-term negative consequences for the clinical management of patients. The most common positions used to perform lumbar puncture are the lateral decubitus and sitting position, and each can impact the success rate and safety of the procedure. However, it is uncertain which position best improves patient outcomes. OBJECTIVES: To assess the benefits and harms of the lateral decubitus, sitting, and prone positions for lumbar puncture in newborn infants. SEARCH METHODS: We used standard, extensive Cochrane search methods. The latest search date was 24 January 2023. SELECTION CRITERIA: We included randomized controlled trials (RCTs) and quasi-RCTs involving newborn infants of postmenstrual age up to 46 weeks and 0 days, undergoing lumbar puncture for any indication, comparing different positions (i.e. lateral decubitus, sitting, and prone position) during the procedure. DATA COLLECTION AND ANALYSIS: We used standard Cochrane methods. We used the fixed-effect model with risk ratio (RR) and risk difference (RD) for dichotomous data and mean difference (MD) and standardized mean difference (SMD) for continuous data, with their 95% confidence intervals (CI). Our primary outcomes were successful lumbar puncture procedure at the first attempt; total number of lumbar puncture attempts; and episodes of bradycardia. We used GRADE to assess the certainty of evidence for each outcome. MAIN RESULTS: We included five studies with 1476 participants. Compared to sitting position: lateral decubitus position may result in little to no difference in successful lumbar puncture procedure at the first attempt (RR 0.93, 95% CI 0.85 to 1.02; RD -0.04, 95% CI -0.09 to 0.01; I2 = 70% and 72% for RR and RD, respectively; 2 studies, 1249 infants, low-certainty evidence). None of the studies reported the total number of lumbar puncture attempts. Lateral decubitus position likely increases episodes of bradycardia (RR 1.72, 95% CI 1.08 to 2.76; RD 0.03, 95% CI 0.00 to 0.05; number needed to treat for an additional harmful outcome (NNTH) = 33; I2 = not applicable and 69% for RR and RD, respectively; 3 studies, 1279 infants, moderate-certainty evidence) and oxygen desaturation (RR 2.10, 95% CI 1.42 to 3.08; RD 0.06, 95% CI 0.03 to 0.09; NNTH = 17; I2 = not applicable and 96% for RR and RD, respectively; 2 studies, 1249 infants, moderate-certainty evidence). The evidence is very uncertain regarding the effect of lateral decubitus position on time to perform the lumbar puncture (MD 2.00, 95% CI -4.98 to 8.98; I2 = not applicable; 1 study, 20 infants, very low-certainty evidence). Lateral decubitus position may result in little to no difference in the number of episodes of apnea during the procedure (RR not estimable; RD 0.00, 95% CI -0.03 to 0.03; I2 = not applicable and 0% for RR and RD, respectively; 2 studies, 197 infants, low-certainty evidence). No studies reported apnea defined as number of infants with one or more episodes during the procedure. Compared to prone position: lateral decubitus position may reduce successful lumbar puncture procedure at first attempt (RR 0.75, 95% CI 0.63 to 0.90; RD -0.21, 95% CI -0.34 to -0.09; number needed to treat for an additional beneficial outcome = 5; I2 = not applicable; 1 study, 171 infants, low-certainty evidence). None of the studies reported the total number of lumbar puncture attempts or episodes of apnea. Pain intensity during and after the procedure was reported using a non-validated pain scale. None of the studies comparing lateral decubitus versus prone position reported the other critical outcomes of this review. AUTHORS' CONCLUSIONS: When compared to sitting position, lateral decubitus position may result in little to no difference in successful lumbar puncture procedure at first attempt. None of the included studies reported the total number of lumbar puncture attempts. Furthermore, infants in a lateral decubitus position likely experience more episodes of bradycardia and oxygen desaturation, and there may be little to no difference in episodes of apnea. The evidence is very uncertain regarding time to perform lumbar puncture. Pain intensity during and after the procedure was reported using a pain scale that was not included in our prespecified tools for pain assessment due to its high risk of bias. Most study participants were term newborns, thereby limiting the applicability of these results to preterm babies. When compared to prone position, lateral decubitus position may reduce successful lumbar puncture procedure at first attempt. Only one study reported on this comparison and did not evaluate adverse effects. Further research exploring harms and benefits and the effect on patients' pain experience of different positions during lumbar puncture using validated pain scoring tool may increase the level of confidence in our conclusions.

Hypercarbia and high-flow nasal oxygen use during anaesthesia - risking a failure to thrive?

Prevention of arterial oxygen desaturation during anaesthesia with high-flow nasal oxygen (HFNO) has gained greater acceptance for a widening range of procedures. However, during HFNO use there remains the potential for development of significant anaesthesia-associated apnoea or hypoventilation and the possibility of hypercarbia, with harmful cardiovascular or neurological sequelae. The aim of this study was to determine whether any HFNO-related hypercarbia adverse incidents had been reported on webAIRS, an online database of adverse anaesthesia-related incidents. Two relevant reports were identified of complications due to marked hypercarbia during HFNO use to maintain oxygenation. In both reports, HFNO and total intravenous anaesthesia were used during endoscopic procedures through the upper airway. In both, the extent of hypoventilation went undetected during HFNO use. An ensuing cardiac arrest was reported in one report, ascribed to acute hypercarbia-induced exacerbation of the patient's pre-existing pulmonary hypertension. In the other report, hypercarbia led to a prolonged duration of decreased level of consciousness post procedure, requiring ventilatory support. During the search, an additional 11 reports of postoperative hypercarbia-associated sedation were identified, unrelated to HFNO. In these additional reports an extended duration of severe acute hypercarbia led to sedation or loss of consciousness, consistent with the known effects of hypercarbia on consciousness. These 13 reports highlight the potential dangers of unrecognised and untreated hypercarbia, even if adequate oxygenation is maintained.

Oxygenation during the apnoeic phase preceding intubation in adults in prehospital, emergency department, intensive care and operating theatre environments.

BACKGROUND: Apnoeic oxygenation is the delivery of oxygen during the apnoeic phase preceding intubation. It is used to prevent respiratory complications of endotracheal intubation that have the potential to lead to significant adverse events including dysrhythmia, haemodynamic decompensation, hypoxic brain injury and death. Oxygen delivered by nasal cannulae during the apnoeic phase of intubation (apnoeic oxygenation) may serve as a non-invasive adjunct to endotracheal intubation to decrease the incidence of hypoxaemia, morbidity and mortality. OBJECTIVES: To evaluate the benefits and harms of apnoeic oxygenation before intubation in adults in the prehospital, emergency department, intensive care unit and operating theatre environments compared to no apnoeic oxygenation during intubation. SEARCH METHODS: We used standard, extensive Cochrane search methods. The latest search date was 4 November 2022. SELECTION CRITERIA: We included randomized controlled trials (RCTs) and quasi-RCTs that compared the use of any form of apnoeic oxygenation including high flow and low flow nasal cannulae versus no apnoeic oxygenation during intubation. We defined quasi-randomization as participant allocation to each arm by means that were not truly random, such as alternation, case record number or date of birth. We excluded comparative prospective cohort and comparative retrospective cohort studies, physiological modelling studies and case reports. DATA COLLECTION AND ANALYSIS: We used standard Cochrane methods. Our primary outcomes were 1. hospital stay and 2. incidence of severe hypoxaemia. Our secondary outcomes were 3. incidence of hypoxaemia, 4. lowest recorded saturation of pulse oximetry (SpO2), 5. intensive care unit (ICU) stay, 6. first pass success rate, 7. adverse events and 8. MORTALITY: We used GRADE to assess certainty of evidence. MAIN RESULTS: We included 23 RCTs (2264 participants) in our analyses. Eight studies (729 participants) investigated the use of low-flow (15 L/minute or less), and 15 studies (1535 participants) investigated the use of high-flow (greater than 15 L/minute) oxygen. Settings were varied and included the emergency department (2 studies, 327 participants), ICU (7 studies, 913 participants) and operating theatre (14 studies, 1024 participants). We considered two studies to be at low risk of bias across all domains. None of the studies reported on hospital length of stay. In predominately critically ill people, there may be little to no difference in the incidence of severe hypoxaemia (SpO2 less than 80%) when using apnoeic oxygenation at any flow rate from the start of apnoea until successful intubation (risk ratio (RR) 0.86, 95% confidence interval (CI) 0.66 to 1.11; P = 0.25, I² = 0%; 15 studies, 1802 participants; low-certainty evidence). There was insufficient evidence of any effect on the incidence of hypoxaemia (SpO2 less than 93%) (RR 0.58, 95% CI 0.23 to 1.46; P = 0.25, I² = 36%; 3 studies, 489 participants; low-certainty evidence). There may be an improvement in the lowest recorded oxygen saturation, with a mean increase of 1.9% (95% CI 0.75% to 3.05%; P < 0.001, I² = 86%; 15 studies, 1525 participants; low-certainty evidence). There may be a reduction in the duration of ICU stay with the use of apnoeic oxygenation during intubation (mean difference (MD) ‒1.13 days, 95% CI ‒1.51 to ‒0.74; P < 0.0001, I² = 46%; 5 studies, 815 participants; low-certainty evidence). There may be little to no difference in first pass success rate (RR 1.00, 95% CI 0.93 to 1.08; P = 0.79, I² = 0%; 8 studies, 826 participants; moderate-certainty evidence). There may be little to no difference in incidence of adverse events including oral trauma, arrhythmia, aspiration, hypotension, pneumonia and cardiac arrest when apnoeic oxygenation is used. There was insufficient evidence about any effect on mortality (RR 0.84, 95% CI 0.70 to 1.00; P = 0.06, I² = 0%; 6 studies, 1015 participants; low-certainty evidence). AUTHORS' CONCLUSIONS: There was some evidence that oxygenation during the apnoeic phase of intubation may improve the lowest recorded oxygen saturation. However, the differences in oxygen saturation were unlikely to be clinically significant. This did not translate into any measurable effect on the incidence of hypoxaemia or severe hypoxaemia in a group of predominately critically ill people. We were unable to assess the influence on hospital length of stay; however, there was a reduction in ICU stay in the apnoeic oxygenation group. The mechanism for this is unclear as there was little to no difference in first pass success or adverse event rates.

Developmental consequences of short apneas and periodic breathing in preterm infants.

OBJECTIVE: We investigated the relationship between respiratory events experienced before and after hospital discharge and developmental outcomes at 6 months corrected age (CA). STUDY DESIGN: Preterm infants born between 28-32 weeks gestational age (GA) were studied at 32-36 weeks postmenstrual age (PMA), 36-40 weeks PMA, 3- and 6-months CA. Percentage total sleep time (%TST) with respiratory events (isolated apneas, sequential apneas and periodic breathing (PB)) at each study was calculated. Stepwise multiple linear regressions determined significant predictors of developmental outcomes at 6 months. RESULT: %TST with respiratory events at term were significant predictors of language (R2 = 0.165, ß = -0.416) and motor (R2 = 0.180, ß = -0.485) composite scores of the Bayley Scales of Infant Development at 6 months, independent of GA, birth weight and sex. CONCLUSIONS: In clinically stable very preterm infants at term equivalent age, time spent having respiratory events, was related to a reduction in language and motor outcomes at 6 months.

Etiology and Mechanism of Intermittent Hypoxemia Episodes in Spontaneously Breathing Extremely Premature Infants.

OBJECTIVE: To evaluate the mechanisms leading to intermittent hypoxemia (IH) episodes in spontaneously breathing extremely premature infants at 32 weeks and 36 weeks postmenstrual age (PMA). METHODS: We studied spontaneously breathing premature infants born at 23-28 weeks of gestational age who presented with IH episodes while on noninvasive respiratory support at 32 or 36 weeks PMA. Daytime recordings of arterial oxygen saturation (SpO2), esophageal pressure, respiratory inductive plethysmography of the abdomen, chest wall, and their sum were obtained during 4 hours at 32 weeks and 36 weeks PMA. IH episodes (SpO2 <90% for ≥5 seconds) and severe IH episodes (SpO2 < 80% for ≥5 seconds) were classified as resulting from apnea, active exhalation and breath holding, reduced tidal volume (VT), or reduced respiratory rate (RR) during the preceding 60 seconds. RESULTS: Fifty-one infants with a mean gestational age of 25.9 ± 1.5 weeks and a mean birth weight of 846 ± 185 g were included. Of these, 31 and 41 were included in the analysis at 32 weeks and 36 weeks PMA, respectively. At both 32 weeks and 36 weeks PMA, greater proportions of all IH episodes and severe IH episodes were associated with active exhalation and breath holding than with apnea, reduced RR, or reduced VT. The severity and duration of the IH episodes did not differ between mechanisms. CONCLUSIONS: In this group of premature infants, the predominant mechanism associated with daytime IH was active exhalation and breath holding. This etiology is more closely associated with behavioral factors than abnormal respiratory control and can have implications for prevention.

Effect of transnasal humidified rapid-insufflation ventilatory exchange on gastric insufflation during anaesthesia induction: A randomised controlled trial and multivariate analysis.

BACKGROUND: Mask ventilation during anaesthesia induction is generally used to provide adequate oxygenation but improper mask ventilation can result in gastric insufflation. It has been reported that oxygen administered by transnasal humidified rapid-insufflation ventilatory exchange (THRIVE) during anaesthesia induction can maintain oxygenation but its effect on gastric insufflation is unknown. OBJECTIVES: The primary aim of this study was to evaluate whether THRIVE provided adequate oxygenation without gastric insufflation. The secondary aim was to explore the change in cross-sectional area of the antrum (CSAa) during anaesthesia induction. Other potential risk factors of gastric insufflation were also explored. DESIGN: A prospective, randomised, double-blind study. SETTING: Single centre, Department of Anaesthesiology, 1 st Affiliated Hospital, Wenzhou Medical University, China, from May 2022 to September 2022. PATIENTS: A total of 210 patients (age >18 years, ASA classification I to III) scheduled to undergo general anaesthesia were enrolled. INTERVENTIONS: For induction of general anaesthesia, patients were randomised into two groups: THRIVE and pressure-controlled facemask ventilation (PCFV). The THRIVE group received high-flow nasal oxygen with no additional ventilation. The PCFV group had pressure-controlled positive pressure ventilation from the anaesthesia machine via a tight fitting facemask. Gastric insufflation was detected using real-time ultrasonography. The CSAa was measured from ultrasonography images obtained before anaesthesia induction and at 0, 1, 2 and 3 min after loss of consciousness. MAIN OUTCOME MEASURES: The incidence of gastric insufflation during the period from loss of consciousness until intubation. RESULTS: The THRIVE group had a lower incidence of gastric insufflation during anaesthesia induction than the PCFV group (13.0 vs. 35.3%, odds ratio (OR) = 0.27, 95% confidence interval (CI), 0.14 to 0.56, P  < 0.001). Increase in the CSA after anaesthesia induction was significantly correlated with gastric insufflation (OR = 5.35, 95% CI, 2.90 to 9.89, P  < 0.001). Multivariate logistic regression analysis showed that advancing age (OR = 1.04, 95% CI, 1.01 to 1.07), obstructive sleep apnoea syndrome (OR = 2.43, 95% CI, 1.24 to 4.76), higher Mallampati score (OR = 2.66, 95% CI, 1.21 to 5.85) and PCFV (OR = 4.78, 95% CI, 2.06 to 11.06) were important independent risk factors for gastric insufflation. CONCLUSION: During anaesthesia induction, the THRIVE technique provided adequate oxygenation with a reduced incidence of gastric insufflation. PCFV, advancing age, obstructive sleep apnoea syndrome and the Mallampati score were found to be independent risk factors for gastric insufflation during anaesthesia induction. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR200059555.

Comparing nasopharyngeal apnoeic oxygenation at 18 l/min to preoxygenation alone in obese patients - A randomised controlled study.

STUDY OBJECTIVE: Investigate a low-cost, nasopharyngeal apnoeic oxygenation technique, establish its efficacy, and compare it to preoxygenation only in an obese population. The study's hypothesis was that nasopharyngeal apnoeic oxygenation at 18 l.min-1 would significantly prolong safe apnoea time compared to preoxygenation alone. DESIGN: Randomised controlled study. SETTING: Theatre complex of a resource constrained hospital. PATIENTS: 30 adult, obese (BMI ≥ 35 kg.m-2) patients presenting for elective surgery. Patients with limiting cardio-respiratory disease, suspected difficult airway, risk of aspiration, and that were pregnant, were excluded. Patients were allocated by block randomisation in a 1:2 ratio to a preoxygenation-only (No-AO) and an intervention group (NPA-O2). INTERVENTIONS: All patients were preoxygenated to an Et-O2 > 80%, followed by a standardised induction. The intervention group received oxygen at 18 l.min-1 via the nasopharyngeal catheter intervention. The desaturation process was documented until an SpO2 of 92% or 600 s was reached. MEASUREMENTS: Baseline demographic and clinical characteristics were collected. The primary outcome was safe apnoea time, defined as the time taken to desaturate to an SpO2 of 92%. Secondary outcomes were rate of carbon dioxide accumulation and factors affecting the risk of desaturation. MAIN RESULTS: The study was conducted in a morbidly obese population (NoAO = 41,1 kg.m-2; NPA-O2 = 42,5 kg.m-2). The risk of desaturation was signifantly lower in the intervention group (Hazzard Ratio = 0,072, 95% CI[0,019-0,283]) (Log-Rank test, p < 0.001). The median safe apnoea time was significantly longer in the intervention group (NoAO = 262 s [IQR 190-316]; NPA-O2 = 600 s [IQR 600-600]) (Mann-Whitney-U test, p < 0.001). The mean rate of CO2 accumalation was significantly slower in the intervention group (NoAO = 0,47 ± 0,14 kPa.min-1; NPA-O2 = 0,3 ± 0,09 kPa.min-1) (t-test, p = 0.003). There were no statistically significant risk factors associated with an increased risk of desaturation found. CONCLUSIONS: Nasopharyngeal apnoeic oxygenation at 18 l/min prolongs safe apnoea time, compared to preoxygenation alone, and reduces the risk of desaturation in morbidly obese patients. CLINICAL TRIAL REGISTRATION: PACTR202202665252087; WC/202004/007.

Safety and Utility of Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE) for Laser Laryngeal Surgery.

OBJECTIVE: Transnasal humidified rapid-insufflation ventilatory exchange (THRIVE) is gaining acceptance as a safe method for apneic ventilation and oxygenation during laryngeal procedures, but remains controversial during laser laryngeal surgery (LLS) due to the theoretical risk of airway fire. This study describes our experience with THRIVE during LLS. STUDY DESIGN: Retrospective cohort study. SETTING: Stanford University Hospital, October 15, 2015 to June 1, 2021. METHODS: Retrospective chart review of patients ≥18 years who underwent LLS involving the CO2 or KTP laser with THRIVE as the primary mode of oxygenation. RESULTS: A total of 172 cases were identified. 20.9% were obese (BMI ≥ 30). Most common operative indication was subglottic stenosis. The CO2 laser was used in 79.1% of cases. Median lowest intraoperative SpO2 was 96%. 44.7% cases were solely under THRIVE while 16.3% required a single intubation and 19.2% required multiple intubations. Mean apnea time for THRIVE only cases was 32.1 minutes and in cases requiring at least one intubation 24.0 minutes (p < .001). Mean apnea time was significantly lower for patients who were obese (p < .001) or had a diagnosis of hypertension (p = .016). Obese patients and patients with hypertension were 2.03 and 1.43 times more likely to require intraoperative intubation, respectively. There were no intraoperative complications or fires since the institution of our LLS safety protocol. CONCLUSION: By eliminating the fuel component of the fire triangle, THRIVE can be safely used for continuous delivery of high FiO2 during LLS, provided adherence to institutional THRIVE-LLS protocols.

Safety and Efficacy of a Novel Approach to Pulmonary Vein Isolation Using Prolonged Apneic Oxygenation.

BACKGROUND: Improved ablation catheter-tissue contact results in more effective ablation lesions. Respiratory motion causes catheter instability, which impacts durable pulmonary vein isolation (PVI). OBJECTIVES: This study sought to evaluate the safety and efficacy of a novel ablation strategy involving prolonged periods of apneic oxygenation during PVI. METHODS: We conducted a multicenter, prospective controlled study of 128 patients (mean age 63 ± 11 years; 37% women) with paroxysmal atrial fibrillation undergoing PVI. Patients underwent PVI under general anesthesia using serial 4-minute runs of apneic oxygenation (apnea group; n = 64) or using standard ventilation settings (control group; n = 64). Procedural data, arterial blood gas samples, catheter position coordinates, and ablation lesion characteristics were collected. RESULTS: Baseline characteristics between the 2 groups were similar. Catheter stability was significantly improved in the apnea group, as reflected by a decreased mean catheter displacement (1.55 ± 0.97 mm vs 2.25 ± 1.13 mm; P < 0.001) and contact force SD (4.9 ± 1.1 g vs 5.2 ± 1.5 g; P = 0.046). The percentage of lesions with a mean catheter displacement >2 mm was significantly lower in the apnea group (22% vs 44%; P < 0.001). Compared with the control group, the total ablation time to achieve PVI was reduced in the apnea group (18.8 ± 6.9 minutes vs 23.4 ± 7.8 minutes; P = 0.001). There were similar rates of first-pass PVI, acute PV reconnections and dormant PV reconnections between the two groups. CONCLUSIONS: A novel strategy of performing complete PVI during apneic oxygenation results in improved catheter stability and decreased ablation times without adverse events. (Radiofrequency Ablation of Atrial Fibrillation Under Apnea; NCT04170894).

Change of gut microbiome structure in preterm infants with hypoxic ischemic encephalopathy induced by apnea.

BACKGROUND: Since a high incidence of mortality and morbidity is induced by preterm birth, it is important to understand how hypoxic ischemic encephalopathy (HIE) in preterm infants alters gut microbiota development. METHODS: We analyzed 89 stools from 30 term newborns (NNG), 30 preterm infants without apnea (PG) and 29 preterm infants with definite diagnosis of apnea (PAG) by 16S rRNA gene sequencing in this study. RESULTS: The data showed that species richness and diversity in PG and PAG were significantly lower compared with NNG. This study investigated the difference in bacteria and relative abundance between NNG, PG and PAG. The abundance of Klebsiella and Streptococcus strains were markedly increased, while Clostridium was significantly decreased in PAG compared with PG. The most notable exceptions included Klebsiella pneumoniae and Escherichia coli, which were markedly increased in PG and PAG, and these provide the main bacterial source of dopamine and serotonin production. This study also revealed that Lactobacillus and Bifidobacterium were markedly increased in PG and PAG, and these are the main source of GABA production for bacteria. CONCLUSION: The present study confirmed that apnea had a uniform effect on species richness and diversity. However, it cannot be established whether the abundance and difference of these bacterial genera and species directly affect the occurrence and development of preterm infants with HIE by secreting intestinal neurotransmitters.

Impact of supplemental anesthesia in preterm infants undergoing inguinal hernia repair under spinal anesthesia : A retrospective analysis.

BACKGROUND: In preterm infants, spinal anesthesia (SpA) is recognized as an alternative to general anesthesia for inguinal hernia repair (IHR); however, some patients require supplemental anesthesia during surgery. The purpose of this study was to investigate the frequency and impact of supplemental anesthesia on perioperative care and adverse respiratory and hemodynamic events. METHODS: A retrospective study of preterm infants undergoing IHR at Heidelberg University Hospital within the first year of life between 2009 and 2018 was carried out. RESULTS: In total, 230 patients (255 surgeries) were investigated. Among 189 procedures completed using SpA 24 patients received supplemental anesthesia. Reasons for supplemental anesthesia included loss of anesthetic effect, returning motor response, and respiratory complications. Compared to SpA alone, no differences were found concerning hemodynamic parameters; however, patients requiring supplemental anesthesia displayed higher rates of postoperative oxygen supplementation and unexpected admission to the intensive care unit. The rate of perioperative apnea was 2.7%. Apneic events exclusively occurred after supplemental anesthesia. Bilateral IHR and duration of surgery were associated with the need for supplemental anesthesia. CONCLUSION: Whereas SpA might be favorable when compared to general anesthesia for IHR, the data indicate that particular caution is required in patients receiving supplemental anesthesia due to the possible risk for adverse respiratory events.

AMPK facilitates the hypoxic ventilatory response through non-adrenergic mechanisms at the brainstem.

We recently demonstrated that the hypoxic ventilatory response (HVR) is facilitated by the AMP-activated protein kinase (AMPK) in catecholaminergic neural networks that likely lie downstream of the carotid bodies within the caudal brainstem. Here, we further subcategorise the neurons involved, by cross-comparison of mice in which the genes encoding the AMPK-α1 (Prkaa1) and AMPK-α2 (Prkaa2) catalytic subunits were deleted in catecholaminergic (TH-Cre) or adrenergic (PNMT-Cre) neurons. As expected, the HVR was markedly attenuated in mice with AMPK-α1/α2 deletion in catecholaminergic neurons, but surprisingly was modestly augmented in mice with AMPK-α1/α2 deletion in adrenergic neurons when compared against a variety of controls (TH-Cre, PNMT-Cre, AMPK-α1/α2 floxed). Moreover, AMPK-α1/α2 deletion in catecholaminergic neurons precipitated marked hypoventilation and apnoea during poikilocapnic hypoxia, relative to controls, while mice with AMPK-α1/α2 deletion in adrenergic neurons entered relative hyperventilation with reduced apnoea frequency and duration. We conclude, therefore, that AMPK-dependent modulation of non-adrenergic networks may facilitate increases in ventilatory drive that shape the classical HVR, whereas AMPK-dependent modulation of adrenergic networks may provide some form of negative feedback or inhibitory input to moderate HVR, which could, for example, protect against hyperventilation-induced hypocapnia and respiratory alkalosis.