SpO2 Nadir Research Articles

Effects of Naltrexone on Sleep Quality and Periodic Breathing at High Altitude.

Foster, Katharine, James D. Anholm, Gary Foster, Suman Thapamagar, and Prajan Subedi. Effects of naltrexone on sleep quality and periodic breathing at high altitude. High Alt Med Biol. 00:000-000, 2024. Objective: This study examined the effects of naltrexone on breathing and sleep at high altitude. Mu-opioid receptor (MOR) agonists have a depressive effect on respiration. Naltrexone is known to block the MOR. We hypothesized that MOR blockade with naltrexone would result in higher nocturnal oxygen saturations, fewer apneas, and improved sleep at high altitude. Methods: This double-blind, placebo-controlled, crossover study included nine healthy volunteers (four females, five males) aged 27.9 (4.6) (mean [standard deviation]) years. Two overnight trips spaced at least 2 weeks apart took participants from Loma Linda, CA (355 m) to the Barcroft Laboratory, CA (3,810 m) for each arm. Participants ingested either 50 mg naltrexone or matching placebo at bedtime. Sleep metrics were recorded using an ambulatory physiological sleep monitor (APSM). Subjective data were measured with the Groningen Sleep Quality Scale, Stanford Sleepiness Scale, and the 2018 Lake Louise Score (LLS) for acute mountain sickness (AMS). Results: Mean overnight SpO2 was lower after taking naltrexone, 81% (6) versus 83% (4) (mean difference 1.9% [2.1, 95% confidence interval or CI = 0.1-3.6, p = 0.040]). The lowest overnight SpO2 (nadir) was lower on naltrexone 70% (6) versus 74% (4) (dif. 4.6% [4.3], CI = 1.0-8.2, p = 0.020). Total sleep time and total apnea-hypopnea index were unchanged. Subjective sleep quality was significantly worse on naltrexone measured via the Groningen Sleep Quality Scale (p = 0.033) and Stanford Sleepiness Scale (p = 0.038). AMS measured via LLS was significantly worse while taking naltrexone (p = 0.025). Conclusion: Contrary to our hypothesis, this study demonstrated a significant decrease in nocturnal oxygen saturation, worse sleep quality, and AMS scores. Further characterization of the MOR's effects on sleep and AMS is needed to evaluate potential exacerbating mechanisms for AMS and poor sleep quality at altitude.

Globus sensation in obstructive sleep apnea patients; A cross-sectional study of 120 patients.

Globus pharyngeus (GP) is a common complaint in many disciplines, especially otolaryngology. Pharyngeal symptoms and abnormalities, including GP, are frequent in obstructive sleep apnea (OSA) patients. This study aims to investigate globus sensation in non-operated OSA patients. After translation and validation, the Laryngopharyngeal Measure of Perceived Sensation (LUMP) was administered to 120 untreated OSA patients. All patients underwent polysomnography and thorough physical examination. The association between LUMP scores and OSA measures was evaluated. LUMP score had a significant correlation with the Epworth Sleepiness Scale (ESS) (Spearman's ρ = 0.269, p = 0.004), and BMI (Spearman's ρ = 0.249, p = 0.007), the anatomical position of the tongue (ρ = -0.191, p = 0.04) and the Friedman grade of tonsils (ρ = 0.241, p = 0.01). It correlated with SpO2 nadir, though it did not reach statistical significance. The results of our study depict a relationship between a self-report measure of globus sensation and daytime sleepiness, BMI and tonsil size. In the absence of a direct relationship between OSA severity parameters and GP, we hypothesize a role for shared comorbidities and anatomical phenotypes. The increased frequency of GP in OSA patients should be considered when evaluating the complications of surgical interventions in these patients.

Early Adverse Respiratory Outcomes in Obese Pediatric Tonsillectomy Patients.

To determine if body mass index (BMI) is predictive of adverse respiratory events (ARE) in the obese pediatric population undergoing tonsillectomy. Case series with chart review. Single institution academic otolaryngology practice. All patients 3 to 12 years old with BMI ≥95th percentile that underwent tonsillectomy March 1, 2011 to July 15, 2020 were included. The study excluded patients with comorbidities that warranted admission independent of BMI, including Trisomy 21, gross developmental delay, neuromuscular disorders, and congenital heart disease. Perioperative AREs following tonsillectomy were recorded. AREs were defined as postoperative desaturation (SpO2 < 90%), intubation, continuous positive airway pressure (CPAP), or new O2 requirement for >2 hours. Eighteen patients (8%) had at least 1 ARE. There were no children age 5 and older with a BMI 95th percentile to 98.9th percentile who had an early adverse respiratory outcome. Preoperative polysomnogram (PSG) metrics, obstructive apnea-hypopnea index (oAHI), and oxygen saturations (SpO2) nadir was significantly different between patients with and without AREs (mean oAHI 54.3 vs 17.4, P = .02; mean SpO2 nadir 73.1% vs 84.5%, P = .05). There was no significant difference in the BMI z score (2.88 vs 2.45, P = .09) between groups. AREs requiring inpatient management are uncommon in obese children after tonsillectomy. BMI is a poor independent indication for admission except at BMI extremes. We found significantly higher oAHI and lower SpO2 nadir on PSG indicate a higher risk for AREs and can guide admission postoperatively. There may be a subset of obese tonsillectomy patients who can be safely discharged home on the day of surgery.

Development of rabbit models of ventilator-associated bacterial pneumonia produced by carbapenem-resistant Pseudomonas aeruginosa.

Ventilator-associated bacterial pneumonia (VABP) is among the most intractable of carbapenem-resistant Gram-negative bacterial infections. New antimicrobial agents are critically needed for the treatment of VABP. However, current conventionally used animal model systems are inadequate to meet this challenge. We, therefore, developed rabbit models of VABP caused by carbapenem-resistant Pseudomonas aeruginosa. Persistently neutropenic New Zealand White rabbits were used throughout the study. The early-phase intubated model (0-24 h) received mechanical ventilation, while the late-phase intubated model (72-96 h) was ambulatory. The following outcome parameters were studied: survival, residual tissue bacterial burden (CFU/g), residual BAL bacterial burden (CFU/mL), lung weights, pulmonary lesion score, histology, O2 saturation, radiographic imaging, and histology. Each anesthetized rabbit received a predetermined endotracheal bacterial inoculum, and ventilators were set to FiO2 = 40% and PEEP = 8 mmHg. Within the first 12 h post-inoculation, mean bacterial burdens in lung tissue and BAL fluid, respectively, were established at approximately 107 CFU/g and 106 CFU/mL, persisted through 24 h in the early-phase model and increased in the late-phase model to approximately 108 CFU/g and 107 CFU/mL. Mean max SpO2 was ≥98 mmHg, and mean nadir SpO2 was ≥68 mmHg. Serial thoracic radiographs demonstrated progressive multilobar pneumonic infiltrates. Lung histology revealed progressive focal bronchopneumonia, coagulative necrosis, intra-alveolar hemorrhage, alveolar epithelial cell necrosis, and bacterial microcolonies. The new rabbit model of VABP produced by carbapenem-resistant Pseudomonas aeruginosa recapitulates the pathophysiological, microbiological, diagnostic imaging, and histological patterns of human disease by which to assess critically needed new antimicrobial agents against this lethal infection.

Correlation Between Body Mass Index and Apnea-Hypopnea Index or Nadir Oxygen Saturation Levels in Patients With Obstructive Sleep Apnea.

Apnea-hypopnea index (AHI) and nadir oxygen saturation (SpO2) are the indexes used to measure the severity of obstructive sleep apnea (OSA). Obesity, measured by body mass index (BMI), is one of the main contributing factors to the onset and severity of OSA in patients. This study was conducted to find the association between BMI and OSA severity indexes, mainly AHI and nadir SpO2 levels. Polysomnography reports of patients with diagnosed OSA in a teaching hospital were retrospectively reviewed. BMI, AHI, and nadir SpO2 levels were recorded from the sleep study reports of the patients. Spearman's Rho test was applied to find the correlation between BMI and AHI/nadir Spo2 levels. A total of 167 patients were included in the study, comprising 83 males and 84 females. The Mann-Whitney U test was utilized to investigate the association between BMI and gender and age groups. The analysis revealed a significant difference in BMI between males and females, with females having a higher BMI. However, there was no significant difference in BMI among individuals in the early middle and late middle age groups. Spearman's Rho test was employed to explore the correlation between BMI and AHI/nadir SpO2 levels. The results indicated no significant correlation between BMI and AHI (p= .122) or nadir SpO2 levels (p= .239). Contrary to common belief, BMI was not linked to the severity of OSA. It implies that several other factors, independent of BMI, play a role in the disease progression and severity.

Influence of Impaired Diffusing Capacity and Sleep-disordered Breathing on Nocturnal Hypoxemia and Health Outcomes in Men with and without Human Immunodeficiency Virus.

Rationale: Nocturnal hypoxemia is common in sleep-disordered breathing (SDB) and is associated with increased morbidity and mortality. Although impaired diffusing capacity of the lung for carbon monoxide (DlCO) is associated with daytime hypoxemia, its influence on SDB-related nocturnal hypoxemia is not known. Objectives: To characterize the effects of DlCO impairment on SDB-related nocturnal hypoxemia and associated health outcomes. Methods: Data from a multicenter cohort of men with and without human immunodeficiency virus (HIV) infection, with concomitant measures of DlCO and home-based polysomnography (n = 544), were analyzed. Multivariable quantile regression models characterized associations between DlCO and several measures of SDB-related hypoxemia (e.g., total sleep time with oxygen saturation as measured by pulse oximetry [SpO2] < 90% [T90]). Structural equation models were used to assess associations of impaired DlCO and SDB-related hypoxemia measures with prevalent hypertension and type 2 diabetes. Results: DlCO impairment (<80% predicted) was associated with sleep-related hypoxemia. Participants with severe SDB (apnea-hypopnea index ⩾ 30 events/h) and impaired DlCO had higher T90 (median difference, 15.0% [95% confidence interval (CI), 10.3% to 19.7%]) and average SDB-related desaturation (median difference, 1.0 [95% CI, 0.5 to 1.5]) and lower nadir SpO2 (median difference, -8.2% [95% CI, -11.4% to -4.9%]) and average SpO2 during sleep (median difference, -1.1% [95% CI, -2.1% to -0.01%]) than those with severe SDB and preserved DlCO. Higher T90 was associated with higher adjusted odds of prevalent hypertension (odds ratio, 1.39 [95% CI, 1.14 to 1.70]) and type 2 diabetes (odds ratio, 1.25 [95% CI, 1.07 to 1.46]). Conclusions: DlCO impairment in severe SDB was associated with sleep-related hypoxemia, prevalent hypertension, and type 2 diabetes. Assessment of SDB should be considered in those with impaired DlCO to guide testing and risk stratification strategies.

Risk factors for collisions attributed to microsleep-related behaviors while driving in professional truck drivers

Sleep-disordered breathing (SDB) is prevalent among professional drivers. Although SDB is a known risk factor for truck collisions attributed to microsleep-related behaviors at the wheel (TC-MRBs), the usefulness of overnight pulse oximetry for predicting TC-MRBs is debatable. This retrospective study assessed the association between overnight pulse oximetry parameters, the Epworth Sleepiness Scale (ESS), and TC-MRBs, confirmed by dashcam footage. This study included 108 matched professional truck drivers (TC-MRBs: N = 54; non-TC-MRBs: N = 54), with a mean age and body mass index of 41.9 ± 11.3 years and 23.0 ± 3.7 kg/m2, respectively. Night-time drivers, 4% oxygen desaturation index (ODI), and nadir oxygen saturation (SpO2) were associated with TC-MRBs (odds ratio [95% confidence interval]: 25.63 [5.88–111.77], p < 0.0001; 2.74 [1.02–7.33], p = 0.045; and 3.87 [1.04–14.39], p = 0.04, respectively). The area under the curve of 4% ODI and nadir SpO2 for TC-MRBs were 0.50 and 0.57, respectively. In conclusion, night-time driving, 4% ODI, and nadir SpO2 were significantly associated with TC-MRBs in professional truck drivers. However, the sensitivity of overnight pulse oximetry parameters to predict TC-MRBs in a real-world application was poor. Therefore, combining subjective and objective assessments such as dashcam video footage may be needed to achieve high accuracy for predicting TC-MRBs among professional truck drivers.

Safety and Efficacy of Adenotonsillectomy in Sickle Cell Disease Patients with Obstructive Sleep Apnea – A Scoping Review

Abstract This scoping review aimed to determine the safety and efficacy of adenotonsillectomy in patients with sickle cell disease (SCD) and obstructive sleep apnea (OSA). Six databases were searched from inception till December 2022 to identify relevant articles, and five articles were selected. Standardized mean difference and 95% confidence interval were used as the effect sizes of the pooled data. Adenotonsillectomy was associated with a significant decrease in the apnea–hypopnea index and a significant increase in nadir O2 and SpO2. However, no differences were detected in the mean annual rates of acute chest syndrome and pain episodes. Adenotonsillectomy appears to improve the health status of SCD patients with OSA and was associated with a wide safety margin. Nevertheless, we recommend larger sample sizes with extended follow-up periods to confirm our findings.

Endoscopic treatment of subglottic stenosis with flexible bronchoscopy via laryngeal mask airway.

To evaluate the safety and efficacy of endoscopic treatment of subglottic stenosis with flexible bronchoscopy via laryngeal mask airway (LMA) approach. The records of all patients who underwent endoscopic surgery for subglottic stenosis (SGS) from November 2019 to January 2023 at an academic medical center were reviewed with attention to demographics, patient comorbidities, airway stenosis characteristics, operative time details, surgical complications, and post-operative course. All patients, >18 years old, with one or more surgeries for SGS using (LMA) for intraoperative airway management were included. Surgeries with suspension microlaryngoscopy were excluded. Patients with glottic stenosis or tracheotomy were excluded. Thirty-five patients underwent 52 procedures meeting inclusion criteria. Mean age was 55 years (range 31-78, SD 13.3) and 33 patients (94%) were female. Mean BMI was 30.9 (range 18.4-60.5, SD 8.8). The most common etiology of stenosis was intubation injury in 17 patients (49%), followed by idiopathic in 13 patients (37%). Cotton-Meyer grade 3 (71-99% narrowing) was seen in 25 patients (71%). Mean anesthesia and surgical operative times were 75.9 min (SD 13.5 min) and 39.7 min (SD 11.0 min), respectively. Mean SpO2 nadir was 94.5% (SD 6.3%). No patients required intraoperative change to rigid laryngoscopy, intubation, or tracheotomy. There were no post-operative complications. Mean surgery-free interval was 12.2 months (SD 6.3). Endoscopic treatment of subglottic stenosis with flexible bronchoscopy and spontaneous ventilation via LMA approach is a safe and effective option, especially in patients with limitations for rigid laryngoscopy and elevated BMI. Level Four (case series) Laryngoscope, 134:2672-2677, 2024.

Physiological Responses to Supramaximal Running Exercise with End-Expiratory Breath Holding up to the Breaking Point.

This study aimed to assess the physiological responses to repeated running exercise performed at supramaximal intensity and with end-expiratory breath holding (EEBH) up to the breaking point. Eight male runners participated in two running testing sessions on a motorized treadmill. In the first session, participants performed two sets of 8 repetitions at 125% of maximal aerobic velocity and with maximum EEBH. Each repetition started at the onset of EEBH and ended at its release. In the second session, participants replicated the same procedure, but with unrestricted breathing (URB). The change in cerebral and muscle oxygenation (Δ[Hbdiff]), total haemoglobin concentration (Δ[THb]) and muscle reoxygenation were continuously assessed. End-tidal oxygen (PETO2) and carbon dioxide pressure (PETCO2), arterial oxygen saturation (SpO2) and heart rate (HR) were also measured throughout exercise.On average, EEBH was maintained for 10.1 ± 1 s. At the breaking point of EEBH, PETO2 decreased to 54.1 ± 8 mmHg, whereas PETCO2 increased to 74.8 ± 3.1 mmHg. At the end of repetitions, SpO2 (nadir values 74.9 ± 5.0 vs. 95.7 ± 0.8%) and HR were lower with EEBH than with URB. Cerebral and muscle Δ[Hbdiff] were also lower with EEBH, whereas this condition induced higher cerebral and muscle Δ[THb] and greater muscle reoxygenation. This study showed that performing repeated bouts of supramaximal running exercises with EEBH up to the breaking point induced a fall in arterial, cerebral and muscle oxygenation compared with the URB condition. These phenomena were accompanied by increases in regional blood volume likely resulting from compensatory vasodilation to preserve oxygen delivery to the brain and muscles.

2557. Development of Rabbit Models of Ventilator-Associated Carbapenem-Resistant Acinetobacter baumannii Pneumonia

Abstract Background Carbapenem-resistant (CR) Gram-negative bacteria are emerging worldwide as global public health threats. Mortality rates from these pathogens are especially high in immunocompromised patients. Ventilator-associated bacterial pneumonia (VABP) is among the most intractable of CR Gram-negative bacterial infections. We therefore aimed to develop rabbit animal models of VABP caused by CR strains of Acinetobacter baumannii. Methods Persistently neutropenic NZW rabbits were used throughout the study. A novel endotracheal tracheostomy system was developed for intubation. The early-phase intubated model (0-24h) received mechanical ventilation, while the late-phase intubated model (72-96h) was ambulatory. Ventilators were set to FiO2=40% and PEEP=8mmHg. The following outcome variables were assessed: survival, residual tissue bacterial burden (log CFU/g), residual BAL bacterial burden (log CFU/mL), lung weights, pulmonary lesion score, histology, pulse O2 saturation, radiographic imaging, pro-inflammatory cytokines, quantitative tissue and BAL PCR, and histology. Results Within the first 12h post-inoculation, mean bacterial burdens in lung tissue and BAL fluid, respectively, which were established at approximately 106 CFU/g and 105 CFU/mL, persisted through 24h in the early-phase model and were increased in the late-phase model (72-96h) to approximately 107 CFU/g, and 106 CFU/mL. Mean Max SpO2 was ≥99 mmHg and mean nadir SpO2 was ≥74 mmHg. Serial thoracic radiographs over the course of 12-96h demonstrated progressive multilobar pneumonic infiltrates, while lung histology revealed progressive development of focal bronchopneumonia, intra-alveolar hemorrhage, alveolar epithelial cell necrosis, macrophage activation, monocytic infiltration, alveolar septal disruption, and microcolonies of bacteria. Conclusion The new rabbit model of VABP produced by CR A. baumannii recapitulates the pathophysiological, microbiological, diagnostic imaging, and histological patterns of human disease by which to assess critically needed new antimicrobial agents against this lethal infection. Disclosures All Authors: No reported disclosures

P009 Time spent with SpO2 below 90% during Sleep is Greater in Children with Down syndrome and OSA than in Typically Developing Children

Abstract Background Children with Down syndrome (DS) have a higher predisposition to obstructive sleep apnoea (OSA) compared to typically developing (TD) children. Children with DS have more frequent dips &amp;lt;90% compared with TD children matched for age, sex and OSA severity. Intermittent hypoxia with repeated desaturations and resaturations is associated with cognitive impairment in children. New methods which calculate the time spent with SpO2 &amp;lt;90% have identified an association with cardiac dysfunction in adults with OSA. We aimed to determine if children with DS and OSA spent longer with SpO2 &amp;lt;90% during sleep compared with TD children. Methods 44 children with DS (3-19 y) and age, sex and OSA severity matched TD children underwent overnight polysomnography. Time spent with SpO2 &amp;lt;90% as a percentage of total sleep time (%TST) was calculated. SpO2 nadir when &amp;lt;90% was recorded. Results SpO2 fell &amp;lt;90% in 32 (73%) children with DS and 15 (34%) TD children. The %TST spent with SpO2 &amp;lt;90% was higher in the DS group (median [IQR] 0.029% [0.004, 0.114]) compared with the TD group (0.000% [0.000, 0.020]; p&amp;lt;0.001). There was no difference in SpO2 nadir between the groups (DS mean±sem 84%±1.1%; TD 85%±1.1) when the SpO2 fell &amp;lt;90%. Conclusion Twice as many children with DS experienced periods of oxygen desaturation below 90% as did TD children matched for age, sex and OSA severity. Although as a %TST, the time spent &amp;lt;90% was small, different physiologically-based metrics to characterise OSA severity and the consequences of recurrent hypoxia in children may be merited.

P031 A Novel Oral Appliance Implementation Protocol Using Nightly Portable Monitoring for OSA Patients Failing CPAP therapy

Abstract Introduction Oral Appliance Therapy (OAT) is an effective second line treatment for OSA. However, OAT devices do not have active efficacy monitoring, hence little is known about methods to best identify the optimal degree of mandibular advancement. Methods Consecutive OSA patients undergoing OAT at a sleep disorders service were recruited to participate in a novel titration protocol using nightly monitoring via a portable device (NightOwl®, Ectosense, Belgium). Demographic &amp; sleep study (PSG) data, and key NightOwl® metrics were collected. A treatment PSG was conducted at conclusion of OAT implementation using identified optimal point of mandibular advancement. Results 80 subjects were recruited (52 male, 65%) with mean (±SD) age 49±12 years, BMI 28±4.4 kg/m2, Epworth score (ESS) 9.1±4.9. Baseline PSG showed mean AHI 28±20 events/hr, nadir SpO2 84±21%, time SpO2&amp;lt;90% 8.3±30 minutes. Blood pressure monitoring at baseline showed mean day BP 123/70mmHg and night BP 106/57mmHg. The mean mandibular advancement implemented was 2.9±1.7mm. Post treatment mean ESS was 5.1±3.5 (p&amp;lt;0.001). 62/68 (91%) subjects reported perceived benefit on OAT, 49/53 (92%) reduced snoring, 51/62 (82%) improved sleep, 49/62 (79%) increased energy. Treatment PSG on completion of the protocol showed AHI 14±10 events/hr (p&amp;lt;0.001), nadir SpO2 82±33% (p&amp;gt;0.05), time SpO2&amp;lt;90% 1.2±21 minutes (p=0.04). 48/63 (76%) met the AHI definition of OAT success. Discussion This study demonstrates a novel OAT protocol which led to minimal degree of mandibular advancement, resulting in high rates of symptom benefit and effective treatment of OSA.

Airway Collapsibility during Drug-Induced Sleep Endoscopy Relates with Clinical Features of Obstructive Sleep Apnea.

Increased pharyngeal collapsibility leads to obstructive sleep apnea (OSA). Positive airway pressure titration during drug-induced sleep endoscopy (DISE-PAP) provides objective collapsibility metrics, the pharyngeal opening pressure (PhOP), and active pharyngeal critical pressure (PcritA ). We examined the interrelationships between risk factors of OSA, airway collapsibility measures, and clinical manifestations of the disease. This is a cross-sectional analysis of consecutive OSA patients undergoing DISE-PAP. Nasal PAP was increased stepwise until inspiratory flow limitation was abolished, signifying PhOP. PcritA was derived from the resulting titration pressure-flow relationships. Clinical data including demographics, anthropometrics, sleep studies, and patient-symptom questionnaires were obtained from the electronic medical record. Multivariate regression was used to evaluate the relationship between risk factors, airway collapsibility, and clinical data. On average, the 164 patients meeting inclusion criteria were middle-aged (54.2 ± 14.7 years), overweight/obese (BMI 29.9 ± 4.5 kg/m2 ), male (72.6%), White (79.3%) and had severe OSA (AHI 32.0 ± 20.5 events/hour). Mean PhOP was 7.5 ± 3.3 cm H2 O and mean PcritA was 0.80 ± 3.70 cm H2 O. Younger age (Standardized β = -0.191, p = 0.015) and higher BMI (Standardized β = 0.176, p = 0.028) were associated with higher PhOP, but not PcritA . PhOP and PcritA were both associated with AHI, supine AHI, and SpO2 nadir. Higher PhOP was associated with higher snoring scores (Standardized β = 0.246, p = 0.008), but not other patient-reported outcomes. Objective assessment of passive and active airway mechanics during DISE relates with clinical risk factors for OSA. Quantitative measures of collapsibility provide accessible and meaningful data, enhancing the standard sleep surgery evaluation. 4 Laryngoscope, 134:1978-1985, 2024.

Factors associated with 30- and 90-day mortality in intubations among critically ill patients.

Emergency intubations are commonly associated with adverse events when performed in critically ill patients. A detailed look at intubation factors and their association with procedural success and mortality has yet to be fully conducted. A total of 299 successive intubations at a tertiary Veteran Affair hospital were analyzed. Situational factors, personnel involved, intubation indications, induction agents, and airway management techniques were prospectively collected and entered into univariable and multivariable analyses to identify factors associated with procedural difficulty and mortality. The use of paralytics was associated with easier intubations (OR: 0.31, 95% CI: 0.11-0.87, p = .03). The use of direct laryngoscopy or video laryngoscopy had no significant association with difficult intubation. Factors associated with increased 30-day mortality were cardiac arrest (OR: 7.90, 95% CI: 2.77-22.50, p < .001), hypoxia as indication for intubation (OR: 2.31, 95% CI: 1.23-4.35, p = .009), and nadir SpO2 < 90% (OR: 2.70, 95% CI: 1.01-7.21, p = .048). Presence of an attending anesthesiologist during intubation was associated with a lower 30-day mortality (OR: 0.11, 95% CI: 0.04-0.29, p < .001). Factors associated with increased 90-day mortality were cardiac arrest (OR: 6.57, 95% CI: 2.23-19.34, p = .001), hypoxia as indication for intubation (OR: 1.97, 95% CI: 1.10-3.55, p = .023), and older age (OR: 1.38, 95% CI: 1.07-1.78, p = .013). Similarly, presence of an attending anesthesiologist was found to be associated with a lower 90-day mortality (OR: 0.19, 95% CI: 0.07-0.50, p = .001). Cardiovascular and respiratory instability were associated with increased 30- and 90-day mortality. Presence of an attending anesthesiologist was associated with a better survival following intubation outside operating room.

Don't hold PAT: watch for and correct oximetry artifact.

Plante DT, Rumble ME. Don't hold PAT: watch for and correct oximetry artifact. J Clin Sleep Med. 2023;19(12):2113-2116.

Predicting New-onset Exertional and Resting Hypoxemia in Fibrotic Interstitial Lung Disease.

Rationale: Hypoxemia in fibrotic interstitial lung disease (ILD) indicates disease progression and is of prognostic significance. The onset of hypoxemia signifies disease progression and predicts mortality in fibrotic ILD. Accurately predicting new-onset exertional and resting hypoxemia prompts appropriate patient discussion and timely consideration of home oxygen. Objectives: We derived and externally validated a risk prediction tool for both new-onset exertional and new-onset resting hypoxemia. Methods: This study used ILD registries from Canada for the derivation cohort and from Australia and the United States for the validation cohort. New-onset exertional and resting hypoxemia were defined as nadir oxyhemoglobin saturation < 88% during 6-minute-walk tests, resting oxyhemoglobin saturation < 88%, or the initiation of ambulatory or continuous oxygen. Candidate predictors included patient demographics, ILD subtypes, and pulmonary function. Time-varying Cox regression was used to identify the top-performing prediction model according to Akaike information criterion and clinical usability. Model performance was assessed using Harrell's C-index and goodness-of-fit (GoF) likelihood ratio test. A categorized risk prediction tool was developed. Results: The best-performing prediction model for both new-onset exertional and new-onset resting hypoxemia included age, body mass index, a diagnosis of idiopathic pulmonary fibrosis, and percent predicted forced vital capacity and diffusing capacity of carbon monoxide. The risk prediction tool exhibited good performance for exertional hypoxemia (C-index, 0.70; GoF, P = 0.85) and resting hypoxemia (C-index, 0.77; GoF, P = 0.27) in the derivation cohort, with similar performance in the validation cohort except calibration for resting hypoxemia (GoF, P = 0.001). Conclusions: This clinically applicable risk prediction tool predicted new-onset exertional and resting hypoxemia at 6 months in the derivation cohort and a diverse validation cohort. Suboptimal GoF in the validation cohort likely reflected overestimation of hypoxemia risk and indicated that the model is not flawed because of underestimation of hypoxemia.

Adenotonsillectomy in Children with Obstructive Sleep Apnea Syndrome: Clinical and Functional Outcomes.

Adenotonsillectomy (AT) is the first-line treatment for pediatric obstructive sleep apnea syndrome (OSAS). Relatively few studies have evaluated the clinical and functional outcomes of AT in children with OSAS, but these studies show that surgery improves behavior and quality of life (QOL). However, residual OSAS after AT is reported in severe cases. This study aimed to retrospectively evaluate the clinical and functional outcomes of AT in a cohort of children with OSAS. We consecutively enrolled children with OSAS who underwent AT and were admitted to our clinic from 1 July 2020 to 31 December 2022. For each participant, medical history and physical examinations were performed. Before and after surgery, all patients underwent a standard polygraphic evaluation, and caregivers completed the OSA-18 questionnaire. A total of 65 children with OSAS, aged 2-9 years, were included. After AT, 64 (98.4%) children showed a reduction in AHI, with median (IQR) values decreasing from 13.4/h (8.3-18.5/h) to 2.4/h (1.8-3.1/h) (p-value < 0.0001). Conversely, median (IQR) SpO2 nadir increased after surgery from 89% (84-92%) to 94% (93-95%) (p-value < 0.0001). Moreover, 27 children (18%) showed residual OSAS. The OSA-18 score decreased after AT from median (IQR) values of 84 (76-91) to values of 33 (26-44) (p-value < 0.0001). A positive significant correlation was found between OSA-18 post-operative scores and AHI post-operative scores (rho 0.31; p-value = 0.01). Our findings indicate that, in children with OSAS, AT is associated with significant improvements in behavior, QOL, and polygraphic parameters. However, long-term post-surgical follow-up to monitor for residual OSAS is highly recommended, especially in more severe cases.

Phenotypical Characterization of Obstructive Sleep Apnea in Premature Infants using Polysomnography.

To use objective quantification of polysomnographic (PSG) parameters in premature infants to define the severity and nature of obstructions (partial hypopnea vs. total obstruction), along with the impact on sleep fragmentation and oxygenation patterns. Retrospective comparison of PSG features in 207 infants (<12 months) referred for sleep disordered breathing. Our study groups included term (> = 37 weeks GA, n = 162) and premature (<37 weeks GA, n = 45) infants. Groups were compared for OSA sleep-stage-specific apnea hypopnea (AHI) indexes (REM and NREM), hypopnea indexes (HI), obstructive apnea indexes (OI) and arousal indexes. Oxygenation was assessed as % of time with SpO2 < 90%, nadir with apneic events and frequency of SpO2 desaturations (>3%) calculated as stage-specific O2 desaturation indexes. Overall, premature infants had greater apnea severity (AHI premature 13.9/h vs. Term 7.9/h, p = 0.018). Additional analyses showed that the primary difference between premature and term infants is seen in the group with partial obstructions (HI index) and severe OSA (OAHI> = 10/h). Premature infants also had greater arousal indexes (premature 13.8/h vs. term 10.5/h, p = 0.003). Although the percentage of time <90% at night and the median SpO2 nadir during apneic events was similar in premature vs. term, O2 desaturation indexes were greater in premature infants (10.3/h in term vs. 18.3/h in prematurity, p = 0.03). Children born premature have an OSA phenotype in infancy characterized by greater severity mostly due to frequent partial obstructions (hypopneas) rather than full obstructions (obstructive apnea). Prematurity is also associated with more intermittent hypoxemia and sleep fragmentation. 3 Laryngoscope, 134:1933-1938, 2024.

Clinical and prognostic characteristics of REM sleep related obstructive sleep apnea in children

Objective: To analyze the clinical and prognostic characteristics of rapid eye movement sleep related obstructive sleep apnea (REM-OSA) in children. Methods: A retrospective analysis was performed on the clinical data of 62 children aged from 2 to 14 years who were admitted to Beijing Children's Hospital, Capital Medical University from December 2017 to April 2021, diagnosed with moderate to severe OSA by polysomnography monitoring (PSG), underwent adenoid tonsillectomy, and completed follow-up 6 months after surgery. There were 45 males (72.6%) and 17 females (27.4%). The age range was 2.0-12.3 years. All children completed the clinical data collection, PSG, OSA-18 quality of life questionnaire and Children's Sleep questionnaire-sleep related breathing disorder subscale at baseline. PSG and OSA-18 quality of life questionnaire were reexamined at 6 months after surgery. Children were divided into REM-OSA group (33 cases) and non-REM-OSA group (29 cases) according to whether the obstructive apnea-hypopnea index (OAHI) during rapid eye movement sleep and OAHI during non-rapid eye movement sleep ratio was≥2. Baseline PSG parameters and scale scores, 6-month postoperative cure rate and OSA-18 quality of life questionnaire scores of the 2 groups were compared, and statistical analysis was performed using SPSS 23.0 software. Results: There were no significant differences in age, sex, body mass index, neck circumference/height ratio, overweight or obesity, history of disease, tonsil and adenoid size between the two groups (all P>0.05). Compared with non-REM-OSA group, REM-OSA group had higher oxygen desaturation index and proportion of SpO2<90% of total sleep time (Z=-2.723, P=0.006;Z=-3.414; P=0.001 respectively), and lower SpO2 nadir (Z=-3.957, P<0.001). The proportion of obstructive apnea in total respiratory events (related to anatomical factors) in REM-OSA group was higher than that in non-REM-OSA group (t=2.840, P=0.006). However, the proportion of central apnea in total respiratory events and arousal index (related to functional factors) in REM-OSA group was lower than that in non-REM-OSA group (t=-2.597, P=0.012;Z=-2.956, P=0.003), and there were no significant differences in other PSG parameters between the two groups (all P>0.05). There was an interaction effect between the two groups in the change trend of OSA cure rate at 6 months after surgery under different baseline OAHI (χ2=4.282, P=0.039). Conclusions: The weight of anatomic factors and functional factors in the etiology of children with REM-OSA and non-REM OSA was different, and the postoperative OSA cure rate of children with different baseline OAHI changed in reverse trend.