Photoplethysmography-new applications for an old technology: a sleep technology review.

Education is integral to the American Academy of Sleep Medicine (AASM) mission. The AASM Emerging Technology Committee identified an important and evolving piece of technology that is present in many of the consumer and clinical technologies that we review on the AASM #SleepTechnology (https://aasm.org/consumer-clinical-sleep-technology/) resource-photoplethysmography. As more patients with sleep tracking devices ask clinicians to view their data, it is important for sleep providers to have a general understanding of the technology, its sensors, how it works, targeted users, evidence for the claimed uses, and its strengths and weaknesses. The focus in this review is photoplethysmography-a sensor type used in the familiar pulse oximeter that is being developed for additional utilities and data outputs in both consumer and clinical sleep technologies. CITATION: Ryals S, Chang A, Schutte-Rodin S, et al. Photoplethysmography-new applications for an old technology: a sleep technology review. J Clin Sleep Med. 2023;19(1):189-195.

Factors affecting need for blood transfusion in paediatric patients undergoing open surgery for hip dysplasia.

BACKGROUND AND OBJECTIVES: The management of intraoperative blood loss in the surgical treatment of paediatric hip dysplasia is resource intensive. There are numerous clinical factors that impact the need for intraoperative transfusion. Identification of patient and surgical factors associated with increased blood loss may reduce the unnecessary use of resources. This study aimed to identify factors predictive of intraoperative transfusion in children undergoing hip dysplasia surgery. MATERIALS AND METHODS: This is a single-centre retrospective review of patients undergoing surgery for hip dysplasia from 1 January 2012 to 15 April 2021. Patient demographic factors, anaesthetic, surgical and transfusion histories were reviewed. Multivariable logistic regression analysis was performed to identify factors predictive of allogeneic red blood cell transfusion requirements during the intraoperative period. RESULTS: This study includes 595 patients who underwent open surgery for hip dysplasia, including 297 (52.6%) classified as developmental dysplasia (DD) and 268 (47.3%) as neuromuscular (NM) with a mean age of 9.1 years (interquartile range 3-14). Intraoperative allogeneic transfusion was identified in 26/297 (8.8%) DD and 73/268 (27.2%) NM patients. Adjusted factors associated with increased odds of intraoperative transfusion were NM (odds ratio [OR] = 2.96, 95% confidence interval [CI] [1.76, 5.00]) and the number of osteotomies performed (OR = 1.82/osteotomy, 95% CI [1.40, 2.35]). Adjusted factors that reduced the odds of transfusion were the use of antifibrinolytics (OR = 0.35, 95% CI [0.17, 0.71]) and regional anaesthesia (OR = 0.52, 95% CI [0.29, 0.94]). CONCLUSION: For children undergoing surgery for hip dysplasia, the number of osteotomies performed is predictive of the need for allogeneic blood transfusion. Antifibrinolytics and regional anaesthesia are associated with reduced risk for allogeneic blood transfusion. Blood management initiatives, such a preoperative optimization of haemoglobin and the use of antifibrinolytics, could target patients at increased risk of intraoperative bleeding and transfusion.

Ultrasound Assessment of Penile Blood Flow Following Caudal Block in Children; A Pilot Study.

OBJECTIVE: To characterize penile arterial and venous blood flow in association with caudal block. METHODS: A prospective observational study was conducted in children undergoing primary circumcision at Texas Children's Hospital between September 10, 2020 and November 23, 2021. The penile artery and venous flow velocity were assessed using Doppler ultrasound pre and post caudal block under state-state anesthetic depth. RESULTS: Ten healthy patients were included in the study with a mean age and weight of 1.3 years and 10.7 kg, respectively. There was no significant difference in mean penile arterial blood flow velocity 0.18 m/s, (95% confidence interval: -1.55 to 1.92; P = .81) or mean dorsal penile vein flow velocity 0.11 m/s (95% confidence interval: -1.12 to 1.33; P = .84) prior to and following caudal block in our pediatric cohort. there was no correlation in the direction of change between the arterial flow and venous flow from before and after caudal block (R2 = 0.03). CONCLUSION: We did not identify an association between penile arterial or venous blood flow and performance of a caudal block in children undergoing circumcision.

Association of Analgesic Block With the Incidence of Complications Following Hypospadias Surgery; A Meta-Analysis.

To examine the association between type of analgesic block and incidence of complications following primary hypospadias correction. Data sources included MEDLINE, Embase, Web of Science and the Cochrane Library, inception-01/2021. Randomized clinical trials, cohort and case control studies reporting original data for patients <18 years of age undergoing primary hypospadias correction with either a penile or caudal block for which outcomes (urethrocutaneous fistula or glans dehiscence) were reported. Two researchers independently extracted data and assessed quality for inclusion. The primary outcome was the incidence of complication within six-months postoperatively based on block performed. Ten studies (3201 patients; range: 54-983) were included. Six studies (cumulative weight 28.6%) favored penile block while 4 studies (cumulative weight 71.4%) favored caudal block. Compared to the reference group of penile blocks, caudal blocks had no significant association with development of complications following primary hypospadias correction (relative risk 1.11, 95% CI (0.88, 1.41); P = .38). When adjusting for meatal location (distal vs proximal) there was no significant association with development of fistulae or glanular dehiscence following primary hypospadias correction with caudal blocks in comparison to the reference group, penile blocks for distal, (relative risk 1.46, 95%CI (0.98, 2.17); P = .065) and proximal (relative risk 0.95, 95% CI (0.58, 1.54); P = .823). The type of analgesic block is not associated with the risk of developing complications following primary hypospadias correction in children. Caudal block should be considered for these urological interventions.

Continuous Positive Airway Pressure Titration During Pediatric Drug Induced Sleep Endoscopy.

OBJECTIVE: To observe the degree of airway collapse at varying levels of continuous positive airway pressure (CPAP) during drug pediatric induced sleep endoscopy. METHODS: Using our institutional anesthesia protocol for pediatric DISE procedures, patients were anesthetized followed by evaluation of the nasal airway, nasopharynx, velum, hypopharynx, arytenoids, tongue base, and epiglottis. CPAP titration was performed under vision to evaluate the degree of airway collapse at the level of the velum. Comparison was made with pre-operative polysomnography findings. RESULTS: Twelve pediatric patients underwent DISE with intraoperative CPAP titration. In 7/12 patients, DISE observed CPAP titration was beneficial in elucidating areas of obstruction that were observed at pressures beyond those recommended during preoperative sleep study titrations. In 3 patients, DISE observations provided a basis for evaluation in children not compliant with sleep study CPAP titration testing. With regard to regions effected, airway collapse was observed at the velum and oropharynx to a greater degree when compared with the tongue base and epiglottis. CONCLUSION: DISE evaluation of the pediatric patient with obstructive sleep apnea may present a source for further patient evaluation with respect to CPAP optimization and severity of OSA assessment, particularly in syndromic patients.

Lung and airway ultrasound in pediatric anesthesia.

Perioperative lung ultrasound is a continuously evolving modality with numerous applications for the pediatric anesthesiologist. Lung ultrasound can be used at the bedside, including intraoperatively, to augment traditional physical examination methods of assessing cardiopulmonary structures and identifying the presence of specific and clinically significant pathology. With regard to the lungs, ultrasound has been shown to be highly sensitive at identification of pulmonary pathologies, particularly those of interest in the acute care setting (eg, pleural effusion, pneumothorax). With its relative ease of performance, lung ultrasound should be considered in the initial evaluation of intraoperative hypoxemia particularly when traditional modes of evaluation are nonexplanatory. This educational review introduces the basic concepts of lung ultrasound as they relate to pediatric anesthesia patients.

Monochromic light reduces emergence delirium in children undergoing adenotonsillectomy; a double-blind randomized observational study.

BACKGROUND: Emergence delirium (ED) is common in pediatric anesthesia. This dissociative state in which the patient is confused from their surroundings and flailing can be self-injurious and traumatic for parents. Treatment is by administration of sedatives which can prolong recovery. The aim of this study was to determine if exposure to monochromatic blue light (MBL) in the immediate phase of recovery could reduce the overall incidence of emergence delirium in children following general inhalational anesthesia. METHODS: This double blinded randomized controlled study included patients ages 2-6 undergoing adenotonsillectomy. Postoperatively, 104 patients were randomization (52 in each group) for exposure to sham blue or MBL during the first phase (initial 30 min) of recovery. The primary outcome was the incidence of emergence delirium during the first phase. We also examined Pediatric Anesthesia Emergence Delirium (PAED) scores throughout the first phase. RESULTS: Emergence Delirium was reported in 5.9% of MBL patients versus 33.3% in the sham group, p = 0.001. Using logistic regression adjusting for age, weight, gender, ASA classification and PAED scores provided an adjusted relative risk ratio of 0.18; 95% CI (0.06, 0.54); p = 0.001 for patients in the MBL group. 23.5% of MBL patients versus 52.9% of sham patients had either ED or PAED scores of 12 or more throughout the first phase of recovery, p = 0.002. This produced an adjusted relative risk of 0.46, 95% CI (0.29, 0.75), p = 0.001. CONCLUSIONS: Monochromatic blue light represents a non-pharmacologic method to reduce the incidence of emergence delirium and PAED scores in children. TRIAL REGISTRATION: #NCT03285243 registered on 15/09/2017.

Incidence of Difficult Laryngoscopy in Adult Congenital Heart Disease Patients: A Retrospective Cohort Study.

OBJECTIVE: To identify the incidence of difficult intubation in patients with adult congenital heart disease (ACHD) undergoing cardiac surgery or catheterization. DESIGN: A retrospective cohort study. SETTING: A single-center academic quaternary pediatric hospital. PARTICIPANTS: All patients were >18 years of age with ACHD undergoing endotracheal intubation within the Heart Center at Texas Children's Hospital between January 2012 and December 2019. INTERVENTIONS: None. MEASUREMENT AND MAIN RESULTS: A retrospective chart review was performed, including patient demographics, preoperative airway assessment and intraoperative airway management characteristics. Airways were categorized as difficult using the Pediatric Difficult Intubation registry operational definitions. For patients classified as having a difficult airway, the preoperative airway examination findings were recorded in addition to factors associated with difficult airway in the adult. The study authors identified 1,029 patients with ACHD who underwent procedures with anesthesia at their institution and were analyzed for the presence of difficult airway. In total, 878 patients were intubated, with 4.3% (n = 38) identified to have difficult airway. The presence of concomitant syndromes was greater in patients with difficult intubations and those who were not intubated compared with those who were not difficult intubations (23.7% and 17.2 v 7.5; p < 0.001), respectively. Most patients did not have typical signs associated with difficult intubation. CONCLUSIONS: The study authors identified an incidence of difficult laryngoscopy in their cohort of ACHD patients to be 4.3%. Their incidences of difficult laryngoscopy were fewer than that reported in adult patients with noncongenital heart disease. Most importantly, the risk factors associated with difficult laryngoscopy in the normal adult may be different from those presenting with ACHD, necessitating further investigation.

An assessment of opioids on respiratory depression in children with and without obstructive sleep apnea.

BACKGROUND: Obstructive sleep apnea is a risk factor for respiratory depression following opioid administration as well as opioid-induced hyperalgesia. Little is known on how obstructive sleep apnea status is associated with central ventilatory depression in pediatric surgical patients given a single dose of fentanyl. METHODS: This was a single-center, prospective trial in children undergoing surgery requiring intubation and opioid administration. Sixty patients between the ages of 2-8 years presenting for surgery at Texas Children's Hospital were recruited. Twenty non-obstructive sleep apnea controls and 30 patients with moderate to severe obstructive sleep apnea met inclusion criteria. Following induction of general anesthesia and establishment of steady-state ventilation, participants received 1 mcg/kg intravenous fentanyl. Ventilatory variables (tidal volume, respiratory rate, end-tidal CO2 , and minute ventilation) were assessed each minute for 10 min. The primary outcome was the extent of opioid-induced central ventilatory depression over time by obstructive sleep apnea status when compared with baseline values. Secondary aims assessed the impact of demographics and SpO2 nadir on ventilatory depression. RESULTS: We found no significant difference in percent decrease in respiratory rate (38.1% and 37.1%; p = .950), tidal volume (6.4% and 5.4%; p = .992), and minute ventilation (35.0 L/min and 35.0 L/min; p = .890) in control and obstructive sleep apnea patients, respectively. Both groups experienced similar percent increases in end-tidal CO2 (4.0% vs. 2.2%; p = .512) in control and obstructive sleep apnea patients, respectively. CONCLUSIONS: In pediatric surgical patients, obstructive sleep apnea status was not associated with significant differences in central respiratory depression following a single dose of fentanyl (1 mcg/kg). These findings can help determine safe opioid doses in future pediatric obstructive sleep apneapatients.

Obstructive Sleep Apnea and Dementia-Common Gene Associations through Network-Based Identification of Common Driver Genes.

BACKGROUND: Obstructive Sleep Apnea (OSA) occurs in 7% of the adult population. The relationship between neurodegenerative diseases such as dementia and sleep disorders have long attracted clinical attention; however, no comprehensive data exists elucidating common gene expression between the two diseases. The objective of this study was to (1) demonstrate the practicability and feasibility of utilizing a systems biology approach called network-based identification of common driver genes (NICD) to identify common genomic features between two associated diseases and (2) utilize this approach to identify genes associated with both OSA and dementia. METHODS: This study utilized 2 public databases (PCNet, DisGeNET) and a permutation assay in order to identify common genes between two co-morbid but mutually exclusive diseases. These genes were then linked to their mechanistic pathways through Enrichr, producing a list of genes that were common between the two different diseases. RESULTS: 42 common genes were identified between OSA and dementia which were primarily linked to the G-coupled protein receptor (GPCR) and olfactory pathways. No single nucleotide polymorphisms (SNPs) were identified. CONCLUSIONS: This study demonstrates the viability of using publicly available databases and permutation assays along with canonical pathway linkage to identify common gene drivers as potential mechanistic targets for comorbid diseases.

Mechanisms, diagnosis, prevention and management of perioperative opioid-induced hyperalgesia.

Opioid-induced hyperalgesia (OIH) occurs when opioids paradoxically enhance the pain they are prescribed to ameliorate. To address a lack of perioperative awareness, we present an educational review of clinically relevant aspects of the disorder. Although the mechanisms of OIH are thought to primarily involve medullary descending pathways, it is likely multifactorial with several relevant therapeutic targets. We provide a suggested clinical definition and directions for clinical differentiation of OIH from other diagnoses, as this may be confusing but is germane to appropriate management. Finally, we discuss prevention including patient education and analgesic management choices. As prevention may serve as the best treatment, patient risk factors, opioid mitigation, and both pharmacologic and non-pharmacologic strategies are discussed.

Lay abstract Opioid-induced hyperalgesia (OIH) occurs when opioid medications worsen rather than decrease pain. We present an educational review of the disorder. Although mechanisms of OIH are thought to primarily start in the brain or brainstem before traveling through the spinal cord to the area of pain in the body, there are likely many causes. We provide a suggested clinical definition and a pathway for clinical differentiation of OIH from other diagnoses to help with management. Finally, we discuss prevention including patient education and medication management choices. As prevention may serve as the best treatment, patient risk factors for OIH, decreased opioid use, and both medication and non-medication strategies are discussed.

The Association of Dexmedetomidine on Perioperative Opioid Consumption in Children Undergoing Adenotonsillectomy With and Without Obstructive Sleep Apnea.

BACKGROUND: Dexmedetomidine is used to reduce opioid consumption in pediatric anesthesia. However, there is conflicting evidence in pediatric adenotonsillectomy literature regarding the total perioperative opioid-sparing effects of dexmedetomidine. The aim of this study was to examine the association between dexmedetomidine and total perioperative opioid consumption in children undergoing adenotonsillectomy. METHODS: This was a retrospective cohort study of the children undergoing adenotonsillectomy surgery at Texas Children's Hospital between November 2017 and October 2018. Intraoperative dexmedetomidine was the exposure of interest. The primary outcome was total perioperative opioid consumption calculated as oral morphine equivalents (OME). Secondary outcomes of interest included opioid consumption and pain scores based on presence and absence of obstructive sleep apnea (OSA) and postanesthesia care unit (PACU) duration. We used multivariable linear regression to estimate the association of dexmedetomidine on the outcomes. RESULTS: A total of 941 patients met inclusion criteria, 697 (74.1%) received intraoperative dexmedetomidine. For every 0.1 µg/kg increase in intraoperative dexmedetomidine, the total perioperative OME (mg/kg) decreases by 0.021 mg/kg (95% CI, -0.027 to -0.015; P < .001). Pain scores did not significantly vary by OSA status. PACU duration increased by 1.14 minutes (95% CI, 0.30-1.99; P = .008) for each 0.1 µg/kg of intraoperative dexmedetomidine. CONCLUSIONS: Dexmedetomidine is associated with an overall perioperative opioid-sparing effect in children undergoing adenotonsillectomy and a small but statistically significant increase in PACU duration. Additionally, children with OSA did not have reduced perioperative opioid consumption.

Parental Assessment of Pain Control Following Pediatric Circumcision: Do Opioids Make a Difference?

OBJECTIVE: To determine whether a postoperative prescription for opioids affects parental assessment of pain control following pediatric circumcision. METHODS: This postoperative survey assessed the parental assessment of pain control in 199 patients, ages<18 years undergoing circumcision. This study was conducted at a quaternary care children's hospital in Houston, Texas from December 2018 to January 2020. Postoperative pain regimens included acetaminophen and ibuprofen or combination hydrocodone/acetaminophen in addition to ibuprofen for postoperative analgesia based on the surgical preference. The primary study outcome was identification of the proportion of parents rating their child's analgesia following pediatric circumcision as poor or inadequate based on the postoperative analgesic regimen. RESULTS: Of the 502 surveys sent, the response rate was 40% (199/502) of those who received the survey email, and 64% (199/308) for those who opened the email. Between the opioid and nonopioid groups, there was no difference in, race/ethnicity (Caucasian; 28% vs 37%; P = .43) or insurance status (insured; 51% vs 45%; P = .44). The proportion of parents who rated their child's pain as poor or inadequately controlled following circumcision was relatively rare:5.5% and 1.1% in the nonopioid and opioid groups, respectively. Parents rating their child's pain as excellent with regards to pain control following circumcision were 61% and 53% in the nonopioids and opioid groups, respectively. CONCLUSION: The results of this study indicate that nonopioid analgesic regimens following pediatric circumcision were not associated with decreased parental satisfaction or an increasing assessment of poor or inadequately controlled pain. Limiting opioid exposure following pediatric circumcision is feasible and does not result in worse parental satisfaction with the analgesic plan.

Effect of Caudal vs. Penile Block on the Incidence of Hypospadias Complications Following Primary Repairs: A Retrospective Cohort Study.

PURPOSE: Primary repair of hypospadias is associated with risk of complications, specifically urethrocutaneous fistula and glanular dehiscence. Caudal block may potentially increase the risk of these complications. Therefore, we studied the incidence of hypospadias complications in children who underwent correction at our institution having received either penile or caudal block. MATERIALS AND METHODS: We analyzed all primary hypospadias repair cases from December 2011 through December 2018 at Texas Children's Hospital with a minimum of 1-year followup for the presence of complications: urethrocutaneous fistula and glanular dehiscence. Surgical (surgeon, operative time, block type, local anesthetic, meatal position) and patient (age at correction, prematurity) factors were additionally analyzed. RESULTS: For the primary aim, 983 patients underwent primary hypospadias correction with a minimum of 1 year of postoperative followup data. There were 897 patients (91.3%) in which no complications were identified and 86 (8.7%) with either urethrocutaneous fistula (81) or glanular dehiscence (5). Of the 86 identified complications, 45/812 (5.5%) were distal, 41/171 (24%) were proximal (p <0.001) with a complication. Rate of complications was not associated with caudal block (OR 0.67, 95% CI 0.41-1.09; p=0.11). On univariable analysis, age (OR 1.12, 95% CI 1.04-1.20; p=0.04), surgical duration (OR 1.02; 95% CI 1.01-1.02; p <0.001), prematurity <32 weeks (OR 4.38, 95% CI 1.54-4.11 p <0.001) and position of meatus as proximal (OR 5.38 95% CI 3.39-8.53; p <0.001) were associated with an increased rate of complications. However, on multivariable analysis, associations of age (OR 1.13, 95% CI 1.05-1.22; p=0.001), surgery duration (OR 1.01, 95% CI 1.01-1.02; p <0.001) and meatal position (OR 3.85, 95% CI 2.32-6.39; p <0.001) were associated with increased rate of complications. CONCLUSIONS: Our data suggest that meatal location, older age, extreme prematurity and surgical duration are associated with increased incidence of complications (urethrocutaneous fistula and glanular dehiscence) following hypospadias correction. Analgesic block was not associated with increased hypospadias complication risk.

Intermittent Hypoxia and Effects on Early Learning/Memory: Exploring the Hippocampal Cellular Effects of Pediatric Obstructive Sleep Apnea.

This review provides an update on the neurocognitive phenotype of pediatric obstructive sleep apnea (OSA). Pediatric OSA is associated with neurocognitive deficits involving memory, learning, and executive functioning. Adenotonsillectomy (AT) is presently accepted as the first-line surgical treatment for pediatric OSA, but the executive function deficits do not resolve postsurgery, and the timeline for recovery remains unknown. This finding suggests that pediatric OSA potentially causes irreversible damage to multiple areas of the brain. The focus of this review is the hippocampus, 1 of the 2 major sites of postnatal neurogenesis, where new neurons are formed and integrated into existing circuitry and the mammalian center of learning/memory functions. Here, we review the clinical phenotype of pediatric OSA, and then discuss existing studies of OSA on different cell types in the hippocampus during critical periods of development. This will set the stage for future study using preclinical models to understand the pathogenesis of persistent neurocognitive dysfunction in pediatric OSA.

Pediatric obstructive sleep apnea revisited: Perioperative considerations for the pediatric Anesthesiologist.

Pediatric obstructive sleep apnea presents in up to 7% of children and represents a constellation from nasal turbulence to cessation in gas exchange. There are numerous end organ sequelae including neurocognitive morbidity associated with persistent OSA. Adenotonsillectomy (AT), the first line therapy for pediatric OSA, has not been demonstrated to reduce all end organ morbidity, specifically neurological and behavioral morbidity. Furthermore, certain at-risk populations are at higher risk from neurocognitive morbidity. Precise knowledge and perioperative planning is required to ensure optimal evidence-based practices in children with OSA. This comprehensive review covers the seminal perioperative implications of OSA, including preoperative polysomnography, pharmacotherapeutics, and postoperative risk stratification.