Caffeine has a multitude of uses in anaesthesia, and numerous studies have evaluated its efficacy and usefulness in various aspects of anaesthesia and medical practice. Its various applications in anaesthesia include its role in awakening from anaesthesia, managing post-dural puncture headache, managing post-sedation paradoxical hyper-activity in children, post-operative bowel paralysis, and apnoea in paediatric populations, that is, apnoea in infancy, paediatric obstructive apnoea, and post-anaesthetic apnoea in pre-mature infants. Though the effects of caffeine on bronchial smooth muscle, neurological, and cardio-vascular systems are well known, the relatively little-known effects on the endocrine and gastro-intestinal (GI) system have been recently taking primacy for eliciting its therapeutic benefits. The literature shows encouraging evidence in favour of caffeine, but unambiguous evidence of caffeine benefits for patients is lacking and needs further investigation. In this narrative review of literature, we summarise the available literature to provide insights into the pharmacokinetics, pharmacodynamics, clinical application of caffeine in modern anaesthetic practice, and evidence available in this field to date. An awareness of the various physiological effects, adverse effects, reported applications, and their evidence will widen the horizon for anaesthesiologists to increase its rational use and advance research in this field. Well-designed randomised controlled trials regarding the various outcomes related to caffeine use in anaesthesia should be planned to generate sound evidence and formulate recommendations to guide clinicians.

UNASSIGNED: We conducted a systematic review to investigate electroencephalography (EEG) changes during periods of acute respiratory events such as apnoea and the effect of respiratory stimulants on EEG features in infants.
UNASSIGNED: Studies examining respiration and EEG-recorded brain activity in human neonates between 28 and 42 weeks postmenstrual age were included. Two reviewers independently screened all records and included studies were assessed using the Joanna Briggs Institute Critical Appraisal Tool. The protocol was registered in PROSPERO (CRD42022339873).
UNASSIGNED: We identified 14 studies with a total of 534 infants. Nine articles assessed EEG changes in relation to apnoea, one assessed hiccups, and four investigated the effect of respiratory stimulants. The relationship between neonatal apnoea and EEG changes was inconsistent; EEG suppression and decreased amplitude and frequency were observed during some, but not all, apnoeas. Respiratory stimulants increased EEG continuity compared with before use.
UNASSIGNED: Current studies in this area are constrained by small sample sizes. Diverse exposure definitions and outcome measures impact inference.
UNASSIGNED: This review highlights the need for further work; understanding the relationship between respiration and the developing brain is key to mitigating the long-term effects of apnoea.

BACKGROUND: Supplemental oxygen administration by apnoeic oxygenation during laryngoscopy for tracheal intubation is intended to prolong safe apnoea time, reduce the risk of hypoxaemia, and increase the success rate of first-attempt tracheal intubation under general anaesthesia. This systematic review examined the efficacy and effectiveness of apnoeic oxygenation during tracheal intubation in children.
METHODS: This systematic review and meta-analysis included randomised controlled trials and non-randomised studies in paediatric patients requiring tracheal intubation, evaluating apnoeic oxygenation by any method compared with patients without apnoeic oxygenation. Searched databases were MEDLINE, Embase, Cochrane Library, CINAHL, ClinicalTrials.gov, International Clinical Trials Registry Platform (ICTRP), Scopus, and Web of Science from inception to March 22, 2023. Data extraction and risk of bias assessment followed the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) recommendation.
RESULTS: After initial selection of 40 708 articles, 15 studies summarising 9802 children were included (10 randomised controlled trials, four pre-post studies, one prospective observational study) published between 1988 and 2023. Eight randomised controlled trials were included for meta-analysis (n=1070 children; 803 from operating theatres, 267 from neonatal intensive care units). Apnoeic oxygenation increased intubation first-pass success with no physiological instability (risk ratio [RR] 1.27, 95% confidence interval [CI] 1.03-1.57, P=0.04, I2=0), higher oxygen saturation during intubation (mean difference 3.6%, 95% CI 0.8-6.5%, P=0.02, I2=63%), and decreased incidence of hypoxaemia (RR 0.24, 95% CI 0.17-0.33, P<0.01, I2=51%) compared with no supplementary oxygen administration.
CONCLUSIONS: This systematic review with meta-analysis confirms that apnoeic oxygenation during tracheal intubation of children significantly increases first-pass intubation success rate. Furthermore, apnoeic oxygenation enables stable physiological conditions by maintaining oxygen saturation within the normal range.
BACKGROUND: Protocol registered prospectively on PROSPERO (registration number: CRD42022369000) on December 2, 2022.

This case report and literature review aim to explore the range of injuries sustained in the sport of freediving. The case report involves a 37-year-old patient who sustained a pneumothorax secondary to freediving. We conducted the literature review to analyse the injuries associated with freediving. We used the combination of search terms \'freediving\", \"injuries\", and \"breath-hold diving\" on the database PubMed®. A total of 40 studies were eligible for inclusion in this review. The search revealed a wide range of ophthalmological, pulmonary, neurological, ear, nose, and throat injuries, along with several fatalities. Freediving is a sport performed in extreme environments and, if undertaken by inexperienced, untrained, or competition divers, can lead to severe injury or even death. However, the risk of damage can be reduced by performing it responsibly with the appropriate training and by using proper safety measures. Future research is warranted into the psychological, physiological, and economic benefits of freediving at both individual and community levels.

OBJECTIVE: Tongue base and hypopharynx are the major sites of obstruction in OSA patients with failed palatal surgery. In recent years, several minimally invasive procedures have been developed to address tongue base obstruction. However, the research focus has consistently been on the effectiveness of surgery in reducing obstructive sleep apnoea rather than on postoperative complications. In this systematic review and metanalysis we aim to review the complication rate of minimally invasive base of tongue procedures for OSAS in adults.
METHODS: PubMed (Medline), the Cochrane Library, EMBASE, Scopus, SciELO and Trip Database.
METHODS: Data sources were checked by three authors of the YO-IFOS sleep apnoea study group. Three authors extracted the data. Main outcome was expressed as the complication rate and 95% confidence interval for each surgical technique.
RESULTS: 20 studies (542 patients) met the inclusion criteria. The mean complication rate is 12.79%; 4.65% for minor complications, 6.42% if they are moderate, and 1.77% if severe. The most reported complication overall is infection, in 1.95% of cases, followed by transient swallowing disorder, occurring in 1.30% of the total sample.
CONCLUSIONS: The heterogeneity amongst the included studies prevents us from obtaining solid conclusions. The available evidence suggests that minimally invasive base of tongue procedures may present a wide spectrum of complication rates, ranging from 4.4% in tongue base radiofrequency to up to 42.42% in tongue base ablation.

Changes in sleep during mid-to-late life are associated with risk for Alzheimer\'s disease (AD). Mechanistic understanding of this association necessitates measurement tools able to quantify these sleep changes longitudinally and accurately. We conducted a systematic review with meta-analysis of validity studies of non-invasive sleep-measuring devices published since 2015 that record sleep metrics associated with AD in adults over 40 (mean 52.9, SD 6.1 years). We reviewed 52 studies, including 32 wearable and ten non-wearable single or multi-sensor devices validated against polysomnography (minimum one night). The apnoea hypopnoea index and oxygen desaturation index were accurately measured across devices. Total sleep time and sleep efficiency were significantly overestimated (p < 0.001) by mean 33.2 minutes and 7.6%, respectively. Slow wave sleep duration was inaccurately measured except by a headband device with electroencephalography. There was no significant difference in accuracy between participants with and without sleep disorders. Studies were undermined by high risk of bias from closed-access algorithms and classification thresholds, and incomplete reporting of accuracy data. Only one study investigated slow wave activity, and none investigated sleep spindles. Nonetheless, we have identified devices that could be used in future studies of sleep and AD risk and discuss some of the limitations of available research.

Children with sleep disordered breathing (SDB) are at an increased risk of neurocognitive impairments. This systematic review with meta-analysis aims to 1) establish whether SDB differentially impacts various neurocognitive domains (intelligence, attention/executive functions, memory, visual spatial skills, and language) and 2) examine the effects of several moderating factors. Database searches, conducted according to the PRISMA guidelines, identified 77 studies that met pre-determined criteria, 63 of which were included in the meta-analysis. Most studies were of moderate to high quality. Children with SDB had significant impairments in all cognitive domains, albeit of different magnitude. The largest impairments were found in intelligence (verbal and overall). With respect to severity of SDB, neurocognitive deficits were evident in children with primary snoring (PS) as well as in children with obstructive sleep apnea (OSA). Other moderators: higher body mass index, younger age at testing, using questionnaires rather than polysomnography, and employing a control group instead of normative data, related to poorer neurocognitive outcomes in select domains. Overall, our study provides robust evidence of multiple neurocognitive impairments in children with SDB, with no evidence of sparing in children with PS. The findings of our study provide impetus for research and interventions for children with SDB across all severities.

Breath-hold diving is an activity that humans have engaged in since antiquity to forage for resources, provide sustenance and to support military campaigns. In modern times, breath-hold diving continues to gain popularity and recognition as both a competitive and recreational sport. The continued progression of world records is somewhat remarkable, particularly given the extreme hypoxaemic and hypercapnic conditions, and hydrostatic pressures these athletes endure. However, there is abundant literature to suggest a large inter-individual variation in the apnoeic capabilities that is thus far not fully understood. In this review, we explore developments in apnoea physiology and delineate the traits and mechanisms that potentially underpin this variation. In addition, we sought to highlight the physiological (mal)adaptations associated with consistent breath-hold training. Breath-hold divers (BHDs) are evidenced to exhibit a more pronounced diving-response than non-divers, while elite BHDs (EBHDs) also display beneficial adaptations in both blood and skeletal muscle. Importantly, these physiological characteristics are documented to be primarily influenced by training-induced stimuli. BHDs are exposed to unique physiological and environmental stressors, and as such possess an ability to withstand acute cerebrovascular and neuronal strains. Whether these characteristics are also a result of training-induced adaptations or genetic predisposition is less certain. Although the long-term effects of regular breath-hold diving activity are yet to be holistically established, preliminary evidence has posed considerations for cognitive, neurological, renal and bone health in BHDs. These areas should be explored further in longitudinal studies to more confidently ascertain the long-term health implications of extreme breath-holding activity.

Apnea is one of the three cardinal findings in brain death (BD). Apnea testing (AT) is physiologically and practically complex. We sought to review described modifications of AT, safety and complication rates, monitoring techniques, performance of AT on extracorporeal membrane oxygenation (ECMO), and other relevant considerations regarding AT. We conducted a systematic scoping review to answer these questions by searching the literature on AT in English language available in PubMed or EMBASE since 1980. Pediatric or animal studies were excluded. A total of 87 articles matched our inclusion criteria and were qualitatively synthesized in this review. A large body of the literature on AT since its inception addresses a variety of modifications, monitoring techniques, complication rates, ways to perform AT on ECMO, and other considerations such as variability in protocols, lack of uniform awareness, and legal considerations. Only some modifications are widely used, especially methods to maintain oxygenation, and most are not standardized or endorsed by brain death guidelines. Future updates to AT protocols and strive for unification of such protocols are desirable.

The aim of this study was to determine whether the Kangaroo position decreased apnoea events in preterm newborns compared with conventional care in incubator.
We conducted a systematic review of clinical trials published in English, French, Spanish and Portuguese. A comprehensive literature search was realised until 2017. The main outcome was apnoea events. Data were extracted and combined in a fixed-effects model. The quality of the evidence was assessed according to the GRADE framework (grading the quality of evidence and the strength of recommendations).
Four original clinical trials were selected. These trials were conducted in India and Nepal, between 2005 and 2016. The systematic review comprised 416 preterm newborns. Three studies were randomised controlled trials and one was quasi-experimental. Meta-analysis showed a statistically significant reduction in apnoea episodes (relative risk [RR] 0.41; 95% confidence interval [CI] 0.22, 0.78). The result remained significant when only the three clinical trials were analysed (RR 0.43; 95% CI 0.23, 0.83). Quality analysis indicated moderate quality because of lack of an appropriate method of randomisation in one study.
The Kangaroo position could have protective effect against apnoea events in preterm infants, decreasing the associated risk of death or long-term disability.