Prolonged Oxygen Desaturation Research Articles

Burden of obstructive sleep apnea in patients with lung cancer and its effect on performance status.

The association between lung cancer and obstructive sleep apnea has remained a matter of debate for years. Obstructive sleep apnea is thought to increase the incidence of lung cancer due to intermittent hypoxaemia and sleep fragmentation. The aim of this study is to assess the prevalence of obstructive sleep apnea in patients with lung cancer and its effect on those patients' performance status. This is a prevalence study that was conducted at Chest Diseases Department, Alexandria Main University Hospitals. We enrolled 153 patients with lung cancer. All patients underwent cardiorespiratory monitoring using a home sleep-testing device. Performance status was assessed using Karnofsky performance status scale. The study included 120 (78.4%) males and 33 (21.6%) females newly diagnosed with lung cancer. The mean age was 59.98 ± 11.11 years. Obstructive sleep apnea (apnea-hypopnea index ≥ 5) was present in 134 (87.6%) patients. Eighty-five (63.4%) patients had mild obstructive sleep apnea, 39 (29.1%) patients had moderate obstructive sleep apnea, and 10 (7.46%) patients had severe obstructive sleep apnea. Prolonged nocturnal oxygen desaturation as demonstrated by time of oxygen saturation spent below 90% (T90%) during total sleep time > 30% was present in 25 (16.3%) patients. There was a significant difference in the median value of Karnofsky performance status scale between patients with lung cancer and associated obstructive sleep apnea and those without obstructive sleep apnea. In conclusion, obstructive sleep apnea is highly prevalent among patients with lung cancer. Performance status is worse among patients with lung cancer in the presence of obstructive sleep apnea. Screening patients with lung cancer for obstructive sleep apnea is important regardless of the presence of classical symptoms of obstructive sleep apnea.

Oxygen desaturation in a transgender man: initial concerns and recommendations regarding the practice of chest binding: a case report

BackgroundOver 1.4 million US adults identify as transgender when gender identity differs from the sex assigned at birth [1]. Although transgender patients face adverse health outcomes, they remain an understudied population [2]. A 2017 study surveyed 411 practicing clinicians and found that 80% had been involved in treating a transgender patient, but 80.6% had never received training on transgender care [3]. The purpose of this report is to describe prolonged desaturation in one case of a transgender patient who wore a chest binder intraoperatively owing to a lack of preoperative recognition.Case presentationA 19-year-old transgender male of African-American descent with anxiety and class 3 obesity presented for an esophagogastroduodenoscopy to evaluate a 2-year history of upper abdominal pain unresponsive to proton pump inhibitor therapy, with a plan for monitored anesthesia care. His medications included sertraline, pantoprazole, zolpidem, ergocalciferol, leuprolide, and testosterone cypionate. Preoperatively, the patient was instructed to remove all clothing and to don a patient gown while in the bathroom. The attending anesthesiologist then conducted the interview and examination in the preoperative holding area. The patient was induced with 250 mg of propofol, and reassuring respirations were noted by capnography. Respirations and oxygen saturation remained stable upon insertion of the endoscope. Four minutes later, the patient’s oxygen saturation rapidly decreased to 50% and end-tidal capnography was lost. The endoscope was removed, and the patient was given 200 mg of propofol and 20 mg succinylcholine. His oxygen saturation recovered to 80% and 100% after 2 and 5 minutes, respectively, of ventilation with 100% inspired oxygen. No further oxygen desaturation was noted throughout the procedure, and the patient was closely monitored for signs of respiratory difficulty during an uneventful postoperative course. After full emergence, it was revealed that the patient had been wearing a chest binder throughout the operative procedure. The patient was counseled on the necessity to communicate the presence of this accessory prior to all future procedures.ConclusionIn the clinical narrative, a healthy patient was observed to have prolonged oxygen desaturation after induction of anesthesia. Laryngospasm was suspected clinically owing to the sudden absence of end-tidal carbon dioxide. Prolonged oxygen desaturation despite appropriate interventions suggests the contribution of additional factors. We speculate that the presence of a chest binder intraoperatively predisposed the patient to more rapid oxygen desaturation less responsive to typical therapy. A chest binder would introduce mechanical restriction to the patient’s breathing owing to its inherent design to compress. Although the patient was asked to remove all clothing, specific instructions were not provided regarding the removal of a chest binder. The presence of chest binding was also absent in the electronic health record, despite the documented presence of the patient’s preferred gender, hormonal therapy regimen, and medical history. Ultimately, this case reflects the gap between practitioner knowledge and hospital guidelines and the practices of transgender patients. In reviewing existing literature and the potential for atelectasis with external compression, we would consider that patients refrain from chest binding for 12–24 hours before surgical procedures, resume no sooner than 24 hours after ambulation, and participate in diagnostic incentive spirometry pre- and postoperatively.

Service Evaluation of the Impact of Capnography on the Safety of Procedural Sedation.

BackgroundCapnography has been associated with a reduced incidence of events related to respiratory compromise during procedural sedation.MethodsA prospective service evaluation was conducted at a large United Kingdom (UK) teaching hospital to assess the impact of capnography on patient safety within four speciality services: bronchoscopy, endoscopy, interventional cardiology, and interventional radiology. Events were defined as provided by the World Society of Intravenous Anaesthesia. One thousand four hundred one patients were enrolled in the evaluation, with 666 patients before and 735 after implementation of capnography. Data was entered as a convenience sample on site in an offline data-collection tool. Results were assessed for the relative reduction in the incidence and resulting adjusted odds ratio for the combined incidence of oxygen desaturation (75–90% for <60s), severe oxygen desaturation (<75% at any time) or prolonged oxygen desaturation (<90% for >60s), bradycardia (>25% from baseline) and tachycardia (>25% from baseline). The adjusted odds ratio was controlled for both procedure and patient characteristics.ResultsAfter implementation of capnography, a significant reduction (43.2%, p ≤ 0.05) in adverse events was observed: 147 adverse events occurred during 666 procedures without capnography compared with 93 adverse events that occurred during 735 procedures with capnography. The adjusted odds ratio for the occurrence of the target adverse events was 0.57 (95% CI: 0.42–0.77). Multivariable linear regression indicated that capnography was a significant predictor (p 0.001) of reduced adverse events.ConclusionThese results suggest improved patient safety following capnography implementation.

Major cardiorespiratory events do not increase after immunizations, eye exams, and other stressors in most very low birth weight infants.

Increased cardiorespiratory events with bradycardia and oxygen desaturation have been reported in very low birthweight (VLBW) infants following stressors such as immunizations. These events are difficult to quantify and may be mild. Our group developed an automated algorithm to analyze bedside monitor data from NICU patients for events with bradycardia and prolonged oxygen desaturation (BDs) and used this to compare BDs 24 hours before and after potentially stressful interventions. We included VLBW infants from 2012-2017 with data available around at least one of four interventions: two-month immunizations, retinopathy of prematurity (ROP) examinations, ROP therapy, and inguinal hernia surgery. We used a validated algorithm to analyze electrocardiogram heart rate and pulse oximeter saturation data (HR, SpO2) to quantify BD events of HR < 100 beats/minute for≥4 seconds with oxygen desaturation < 80%SpO2 for≥10 seconds. BDs were analyzed 24 hours before and after interventions using Wilcoxon rank-sum tests. In 354 of 493 (72%) interventions, BD frequency stayed the same or decreased in the 24 hours after the event. An increase of at least five BD's occurred in 17/146 (12%) after immunizations, 85/290 (29%) after ROP examinations, 4/33 (12%) after ROP therapy, and 3/25 (12%) after hernia surgery. Infants with an increase in BDs after interventions had similar demographics compared to those without. More infants with an increase in BDs following immunizations were on CPAP or caffeine than those without. Most VLBW infants in our cohort had no increase in significant cardiorespiratory events in the 24 hours following potentially stressful interventions.

Adverse events during sedation for oro-dental trauma in an Israeli paediatric emergency department.

There is a paucity of data regarding the safety of the practice of sedation for oro-dental trauma in paediatric emergency departments (ED). A previous study reported the safety of intramuscular ketamine administered as a single agent. In the paediatric ED of a tertiary trauma centre in Israel, one of two ketamine-based regimens is used for sedating children with intraoral injuries according to the physician's discretion: a single dose of intramuscular ketamine or a combination of ketamine and propofol (KP) intravenously. The aim of this study was to assess the safety of KP sedation in children undergoing emergency treatment of oro-dental injuries in this paediatric ED. The primary outcome was sedation adverse events that required intervention (SAERI): prolonged oxygen desaturation and apnoea, laryngospasm, hypotension, bradycardia, partial or complete airway obstruction, and pulmonary aspiration. During the 2years study period, 17 children were sedated with KP, 20 with intramuscular ketamine and 29 with nitrous oxide. Patients who were treated with ketamine-based sedation or with nitrous oxide sedation had a median (interquartile range, IQR) age of 3 (2-4)years and 7 (5-9)years, respectively. No SAERI occurred in patients who were sedated with intramuscular ketamine. One (3.4%) SAERI was reported in a patient who was sedated with N2 O. Six/17 (35%) SAERI occurred in patients who were sedated with KP. These findings suggest that caution should be used when young children with oro-dental injuries are sedated with KP in the ED.

S0542 Intraoperative Morbidity Associated With Monitored Anesthesia Care in Obese Patients Undergoing Average Risk Colorectal Cancer Screening

INTRODUCTION: Average risk Colorectal Cancer (CRC) screening colonoscopy requires procedural sedation and monitored anesthesia care (MAC). Elevated BMI is associated with higher prevalence of comorbid conditions including obstructive sleep apnea, hypertension, and pulmonary hypertension. Pre-existing comorbidities, including obesity, may be associated with increased intraoperative cardiopulmonary (ICP) morbidity related to procedural sedation. The aim of our quality improvement project was to evaluate intraoperative morbidity associated with MAC during screening colonoscopy in obese patients. METHODS: Data were collected by retrospective chart review of 304 randomly selected patients undergoing average risk CRC screening colonoscopy at Allegheny Health Network. Demographic data for obese (n = 152) and non-obese (n = 152) cohorts were collected (Table 1). BMI and intraoperative indices including arrhythmia, hypotension, and oxygen saturation, were extracted and analyzed using Pearson’s Chi-Squared Test. Independent T-Test was performed to compare average oxygen desaturation time (ODT). RESULTS: 77.3% of patients were BMI 25–29.9 (27.3%), 30–40 (25.3%) and ≥40 (24.7%) (Table 1). 52.6% of obese patients experienced oxygen desaturation (SaO2 < 95%) as compared to 46.7% in non-obese patients, but this was not statistically significant. Obese patients did have lower mean initial SaO2 and statistically significant increased time with SaO2 < 95% (P = .007). There was no statistically significant association between obesity and intraoperative complications including hypotension, arrhythmia, and hypoxia. CONCLUSION: Our study shows no statistically significant difference in ICP morbidity related to obesity(BMI >30), except for ODT. These findings suggest that patients with obesity are at higher risk of prolonged oxygen desaturation during MAC assisted colonoscopies. Further larger studies are needed to evaluate the clinical implications of prolonged ODT in obese patients.Table 1.: Patient demographics and comorbiditiesTable 2.: Rates of intraoperative cardiopulmonary complications in obese and non-obese patients while under MAC during screening colonoscopyTable 3.: A and 3B. 3A: T-test for Equality of Means showing statistically significant increased ODT minutes in obese patients; 3B: Obese vs. Non-Obese Group Statistics for intraprocedural oxygenation status

S0286 Intra-Operative Morbidity Associated With Monitored Anesthesia Care in Obstructive Sleep Apnea Patients Undergoing Average Risk Colorectal Cancer Screening

INTRODUCTION: Screening colonoscopies are recommended for all patients who are 50 years of age and are at average risk for colorectal cancer (CRC). Monitored anesthesia care (MAC) decreases patient discomfort and improves tolerance of the procedure. Patients with obstructive sleep apnea (OSA) are considered to be at a higher risk for cardiopulmonary complications while under anesthesia. The aim of our quality improvement project is to evaluate intraoperative cardiopulmonary (ICP) morbidity associated with MAC anesthesia in patients with OSA undergoing average risk CRC screening colonoscopy. We postulated that patients with OSA would have higher ICP morbidity compared to those without OSA. METHODS: Retrospective data was collected on 304, 152 obese and 152 non-obese, randomly selected patients who underwent average risk CRC screening colonoscopy at Allegheny Health Network. Diagnostic and high-risk screening colonoscopies were excluded. Table 1 shows the overall population analysis. A total of 66 patients with documented OSA and 238 patients without OSA were included in the data analysis. Pertaining data was collected by chart review and analyzed using Pearson’s chi-squared test. Average oxygen desaturation time (ODT) was compared with ODT in patients with a diagnosis of OSA using independent T-Test. A sub-analysis of ODT in patients with OSA with and without home CPAP was performed using independent T-Test. RESULTS: Comparatively, the OSA group did not have a statistically different rate of hypoxia (P = 0.801), the need for airway change (P = 0.719), cardiac arrhythmia (P = 0.123), or hypotension (P = 0.081) (Table 2). However, total ODT was significantly higher in OSA patients compared to patients without OSA (P = 0.009) (Table 3A). Interestingly, home CPAP use in OSA did not show a significant correlation with ODT (P = 0.753) (Table 3C). CONCLUSION: Our study shows that there are no statistically significant differences in ICP morbidity based on a history of OSA, except for ODT. These findings suggest that patients with OSA are at higher risk of prolonged oxygen desaturation during MAC assisted screening colonoscopies. Further studies are required to assess if patients with OSA are preemptively placed on a higher FiO2 or level of airway than patients without OSA, which could possibly lead to statistically skewed results.Table 1.: Patient demographics and comorbiditiesTable 2.: Rates of cardiopulmonary complications in patients with and without OSA while under conscious sedation during screening colonoscopyTable 3.: A: T-test for equality of the means showing statistically significant increased average oxygen desaturation time in patients with OSA compared to patients without OSA. B: OSA vs No OSA group statistics. C: T-Test for equality of the means showing no significant difference in average oxygen desaturation time in patients with OSA on CPAP compared to patients with OSA, not on CPAP. D: CPAP vs No CPAP group statistics

Safety of bronchoscopy in patients with malignant hematologic disorders

BackgroundFactors affecting the safety of bronchoscopy in patients with malignant hematologic disorders have not been well described. We evaluated the safety of bronchoscopy and describe factors affecting its complication rate in such patients.MethodsBetween January 2009 and December 2018, 316 bronchoscopies in 282 patients with malignant hematologic disorders and pulmonary infiltrates were performed at our institution. The bronchoscopic procedure used and its complications were evaluated.ResultsThe most common underlying disease was acute myeloid leukemia (134/282 patients, 47.5%). Platelet transfusion was performed the day before or the day of bronchoscopy in 42.4%, supplemental oxygen was administered before the procedure in 23.1%, and midazolam was used in 74.4%. Thirty-five bronchoscopies (11.1%) were complicated by hemoptysis and 7 patients developed pneumothorax, 4 of whom required thoracic drainage. Two patients (0.6%) were intubated within 48 h of the procedure and prolonged oxygen desaturation (> 48 h) occurred in 3.8%. Multivariate analysis showed that only use of midazolam significantly reduced the risk of prolonged oxygen desaturation (hazard ratio 0.28, 95% confidence interval 0.09–0.85, p = 0.03). Transbronchial lung biopsy significantly increased the risk of hemoptysis (hazard ratio 10.40, 95% confidence interval 4.18–25.90, p = 0.00), while use of midazolam significantly reduced the risk (hazard ratio 0.31, 95% confidence interval 0.14–0.73, p = 0.01).ConclusionsBronchoscopy is relatively safe in patients with malignant hematologic disorders. Caution and judicious use of sedatives may improve the patient’s procedural tolerance and lower complications.

1072 OSA and IPF Exacerbations: A Deadly Duo

Obstructive sleep apnea (OSA) is common in Idiopathic Pulmonary Fibrosis (IPF) patients. IPF Patients with poorly controlled OSA appear to have worse in quality of life and possibly higher mortality than those with well controlled OSA. The role of OSA in IPF exacerbation is currently unknown. A 71 y/o man with PMH of IPF and OSA (on nocturnal BIPAP 16/4) presented to the ER with worse cough, dyspnea, and hypoxia. He was admitted to the ICU with a diagnosis of IPF exacerbation. He was restarted on his home BIPAP settings. His dyspnea improved, but did not quite return to baseline. An inpatient BIPAP titration study showed that the patient had significant obstructive hypopneas, as well as hypoxia and tachycardia, until his BIPAP was titrated up to 22/10 cm. At this pressure, his tachycardia, hypoxia, and hypopneas resolved. The patient’s BIPAP was adjusted to the new settings. Over the next few days, his dyspnea improved, and he was discharged. About six weeks after discharge, the patient returned to the sleep clinic for follow up. Review of his BIPAP machine data showed that he had developed new central apneas (27 per hour; none previously noted). The patient was diagnosed with severe treatment-emergent central sleep apnea. BIPAP settings were reduced to 13/7. Non-adherence to nocturnal BIPAP may be a risk factor for hospital admission in patients with OSA and IPF. Patients experiencing an acute exacerbation of IPF may temporarily require higher BIPAP settings. However, continued use of higher pressures after resolution of the exacerbation may lead to emergence of central sleep apnea. o Bosi M et al. “OSA and Prolonged Oxygen Desaturation During Sleep are Strong Predictors of Poor Outcome in IPF.” Lung (2017) 195:643–651. o Mermigkis C et al. “Obstructive sleep apnea should be treated in patients with idiopathic pulmonary fibrosis.” Sleep Breath (2015) 19:385–391. o Kim JS et al. “Obstructive Sleep Apnea and Subclinical Interstitial Lung Disease in the Multi-Ethnic Study of Atherosclerosis (MESA).” Ann Am Thorac Soc Vol 14, No 12, pp 1786–1795, Dec 2017.

OSA and Prolonged Oxygen Desaturation During Sleep are Strong Predictors of Poor Outcome in IPF.

Sleep Breathing Disorders (SBD) are frequently found in idiopathic pulmonary fibrosis (IPF) and they are associated with worse quality of sleep and life and with higher mortality. The study aimed at evaluating the impact of SBD on prognosis (mortality or disease progression) in 35 patients with mild to moderate IPF. Obstructive sleep apnea (OSA) was diagnosed in 25/35 patients with IPF: 14/35 mild, 7/35 moderate, and 4/35 severe. According to the American Academy of Sleep Medicine (AASM) definition, sleep-related hypoxemia was found in 9/35 patients with IPF. According to the presence/absence of SBD, IPF patients were divided into 4 groups: NO-SBD group (Group A, 25.7%), OSA without sleep-related hypoxemia (Group B, 48.5%), OSA with sleep-related hypoxemia group (Group C, 22.8%), and only 1/35 had sleep-related hypoxemia without OSA(Group D, 2.8%). Statistical analysis was focused only on group A, B, and C. Patients with OSAS and sleep-related hypoxemia (Group C) had the worse prognosis, both in terms of mortality or clinical deterioration. SBD were the only independent risk factor (Cox Proportional Hazards Multiple Regression Analysis) for mortality (HR 7.6% IC 1.2-36.3; p=0.029) and disease progression (HR 9.95% IC 1.8-644.9; p=0.007). SBD are associated with a worse prognosis, both in terms of mortality or clinical progression. The presence of SBD should be explored in all IPF patients.

Immediate Sequential Bilateral Pediatric Vitreoretinal Surgery: An International Multicenter Study

To determine the feasibility and safety of bilateral simultaneous vitreoretinal surgery in pediatric patients. International, multicenter, interventional, retrospective case series. Patients 17 years of age or younger from 24 centers worldwide who underwent immediate sequential bilateral vitreoretinal surgery (ISBVS)-defined as vitrectomy, scleral buckle, or lensectomy using the vitreous cutter-performed in both eyes sequentially during the same anesthesia session. Clinical history, surgical details and indications, time under anesthesia, and intraoperative and postoperative ophthalmic and systemic adverse events were reviewed. Ocular and systemic adverse events. A total of 344 surgeries from 172 ISBVS procedures in 167 patients were included in the study. The mean age of the cohort was 1.3±2.6 years. Nonexclusive indications for ISBVS were rapidly progressive disease (74.6%), systemic morbidity placing the child at high anesthesia risk (76.0%), and residence remote from surgery location (30.2%). The most common diagnoses were retinopathy of prematurity (ROP; 72.7% [P < 0.01]; stage 3, 4.8%; stage 4A, 44.4%; stage 4B, 22.4%; stage 5, 26.4%), familial exudative vitreoretinopathy (7.0%), abusive head trauma (4.1%), persistent fetal vasculature (3.5%), congenital cataract (1.7%), posterior capsular opacification (1.7%), rhegmatogenous retinal detachment (1.7%), congenital X-linked retinoschisis (1.2%), Norrie disease (2.3%), and viral retinitis (1.2%). Mean surgical time was 143±59 minutes for both eyes. Higher ROP stage correlated with longer surgical time (P= 0.02). There were no reported intraoperative ocular complications. During the immediate postoperative period, 2 eyes from different patients demonstrated unilateral vitreous hemorrhage (0.6%). No cases of endophthalmitis, choroidal hemorrhage, or hypotony occurred. Mean total anesthesia time was 203±87 minutes. There were no cases of anesthesia-related death, malignant hyperthermia, anaphylaxis, or cardiac event. There was 1 case of reintubation (0.6%) and 1 case of prolonged oxygen desaturation (0.6%). Mean follow-up after surgery was 103 weeks, and anatomic success and globe salvage rates were 89.8% and 98.0%, respectively. This study found ISBVS to be a feasible and safe treatment paradigm for pediatric patients with bilateral vitreoretinal pathologic features when repeated general anesthesia is undesirable or impractical.

A Prospective Analysis of the Efficacy and Complications Associated With Deep Sedation With Midazolam During Fiberoptic Bronchoscopy.

Moderate sedation has been commonly used for fiberoptic bronchoscopy (FB). However, patients may find FB under moderate sedation to be unpleasant. We therefore examined whether deep sedation was a useful premedication for FB. We designed a prospective, randomized study using a patient questionnaire to address the perceptions of the procedures and complications of patients who underwent FB with deep sedation (deep sedation group) with midazolam in comparison with those who underwent FB with moderate sedation (moderate sedation group) with the same drug. Patients were asked to grade FB as being easy or difficult to tolerate. The primary endpoint was tolerability and the secondary endpoints included complications associated with the procedure. A total of 80 patients were included in the study. A significantly lower number of patients in the deep sedation group reported that the technique was difficult to tolerate (5.0% vs. 40.0%, moderate sedation group; P<0.001). However, the dose of oxygen required to maintain an oxygen saturation of ≥90% was higher in the deep sedation group (7.3±4.7 vs. 2.7±1.6 L/min; P<0.0001). There were no cases of prolonged oxygen desaturation or deaths related to FB in either group. In the present study, deep sedation had a beneficial effect on patient tolerance to FB. Although oxygen desaturation during FB represents a potentially serious complication, deep sedation may be considered to be a useful premedication for FB.

Actigraphy- and Polysomnography-Measured Sleep Disturbances, Inflammation, and Mortality Among Older Men.

To evaluate whether objectively measured sleep characteristics are associated with mortality risk independent of inflammatory burden and comorbidity. The Osteoporotic Fractures in Men Sleep Study (conducted in 2003-2005) included community-dwelling older men (n = 2531; average [standard deviation {SD}] age = 76.3 (5.5) years). Sleep measures from in-home polysomnography and wrist actigraphy and assessments of serum inflammatory markers levels (C-reactive protein, interleukin-6, tumor necrosis factor α, tumor necrosis factor α soluble receptor II, and interferon-γ) were obtained. Vital status was ascertained over an average (SD) follow-up of 7.4 (1.9 SD) years. Three of the seven main sleep measures examined were independently associated with greater inflammatory burden. Mortality risk associated with prolonged (≥10% total sleep time) blood oxygen desaturation and short (<5 hours) sleep duration was attenuated to nonsignificance after adjusting for inflammatory burden or medical burden/lifestyle factors. Severe blood oxygen desaturation (adjusted hazard ratio [aHR] = 1.57, 95% confidence interval [CI] = 1.11-2.22), sleep fragmentation (aHR = 1.32, 95% CI = 1.12-1.57), and a lower percentage of sleep in rapid eye movement (aHR per SD = 0.90, 95% CI = 0.93-0.97) were independently associated with mortality. Short sleep duration and prolonged blood oxygen desaturation were independently associated with inflammatory burden, which attenuated associations between these sleep characteristics and mortality. Medical and life-style factors also substantially attenuated most sleep-mortality associations, suggesting complex relations between sleep, inflammation, and disease. Sleep fragmentation, severe blood oxygen desaturation, and the percentage of sleep time in rapid eye movement were independently related to mortality risk. Future studies with repeated measures of mediators/confounds will be necessary to achieve a mechanistic understanding of sleep-related mortality risk.

Nocturnal Hypoxemia (not sleep apnea) May Drive Reticulocytosis in Sickle Cell Disease

Introduction: Obstructive sleep apnea is a ventilatory defect that affects up to 10% of children with sickle cell disease (SCD). Sleep apnea has been implicated in cardiovascular disease in non-SCD adults and in cerebrovascular disease in children with SCD. In addition, prolonged hemoglobin oxygen desaturation from sleep disorderedbreathing would be predicted to increase sickle polymer formation and, possibly, activity of disease. We evaluated symptomatic adults from our SCD clinic for sleep apnea, in an effort to identify treatable disease modifying conditions.Methods: 46 adults with SCD were evaluated by polysomnography (PSG) between 2012 and 2014. Subjects were referred for symptoms or signs suggestive of sleep disordered breathing, including nighttime pain, snoring, early morning headache, narrow hypo-pharynx, and/or excessive reticulocytosis. Clinical characteristics of homozygous (HbSS, n=34) and compound heterozygous (HbSC and HbSBeta+Thalassemia, n=12) subjects are shown in Table 1.Results: Sleep apnea was diagnosed if the apnea/hypopnea index (AHI) was elevated: 5-15 (mild), 15-30 (moderate), or >30 (severe).Over half of our patients had sleep apnea by these criteria (16/34 HbSS and 7/12 compound heterozygotes). An elevated 3% oxygen desaturation index , i.e. >15 episodes per hour during which oxygen saturation dropped by 3% or more, was seen in one-third (14/43) of all evaluable subjects, and was 17 (median, range 1.2- 192.4) in subjects with, compared with 4.6 (median, range 1-23.7) in subjects without, sleep apnea (P<.001). Sleep apnea was moderate or severe in 5/34 (14.7%) and 3/12 (25%) of screened HbSS and compound heterozygote patients, respectively. However, the presence of sleep apnea, compared with the absence of sleep apnea, was not associated with differences in measured clinical variables including WBC, Hgb, absolute reticulocyte count, LDH, urinary albumin-to-creatinine ratio, or tricuspid regurgitant jet velocity.We then examined 8 subjects (7 HbSS, 1 SBeta+ thal) whose PSG showed >10% of sleep time afflicted by nocturnal hypoxemia. A median of 33.75% (range 16-98.6%) of sleep time was spent at <90% oxygen saturation in these subjects. Only 3 of 8 subjects with nocturnal hypoxemia had sleep apnea, based on an AHI >5, which was not different than the group as a whole (P=0.7). These 8 subjects had strikingly increased reticulocyte counts, compared with 38 subjects without nocturnal hypoxemia (median 460, range 100-923 (x103)/μL compared with median 303, range 76-733 (x103)/μL respectively, p=0.04), as well as a trend toward a higher LDH (median 488, range 140-752, compared with median 318, range 139-823, P=.08). Of note, hemoglobin levels were not different between subjects with and without nocturnal hypoxemia (mean 8.4±1.5 g/dL compared to mean 9.5±2.2 g/dL, respectively, p=0.17).Conclusions & Discussion: These studies suggest that, while sleep apnea is common in adults with SCD, greater physiological relevance may arise instead from prolonged nocturnal hypoxemia and associated reticulocytosis. We speculate that significant nighttime hypoxemia and hemoglobin desaturation may stimulate both endogenous erythropoietin (and therefore reticulocyte) production and HbS polymer formation and, possibly, hemolysis. This condition, while identifiable by conventional PSG, is not coincident with sleep apnea, and may be modulated by nighttime oxygen supplementation. These findings deserve confirmation in a larger cohort of patients. Table IClinical Characteristics of adults with SCD who underwent PolysomnographyHbSS(n=34)Compound Heterozygous (HbSC, n=8, HbSβ+Thal, n=4)P ValueAge (years)27 (19-50)29.5 (19-51)n.s.Body Mass Index23.8 (17.8-37.6)27.2 (20.1-59.8)n.s.Hgb (g/dL, mean±std dev)8.7±1.910.9±2.0P=.003ARC* (x103/μL),350 (93-923)200 (71-398)P=.004LDH (IU/L)398 (149-823)200 (140-632)P<.001TRV**(m/s)2.5 (n.d.-3.51)1.9 (n.d.-2.64)P<.001*Absolute reticulocyte count **Tricuspid regurgitant jet velocity ¦Median with range, unless otherwise indicated. DisclosuresNo relevant conflicts of interest to declare.

Long-Term Monitoring of Oxygen Saturation at Altitude Can Be Useful in Predicting the Subsequent Development of Moderate-to-Severe Acute Mountain Sickness

The use of pulse oximetry (Spo2) to identify subjects susceptible to acute mountain sickness (AMS) is the subject of debate. To obtain more reliable data, we monitored Spo2 for 24 hours at altitude to investigate the ability to predict impending AMS. The study was conducted during the climb from Alagna (1154 m) to Capanna Regina Margherita (4559 m), with an overnight stay in Capanna Gnifetti (3647 m). Sixty subjects (11 women) were recruited. Each subject was fitted with a 24-hour recording finger pulse oximeter. The subjects rode a cable car to 3275 m and climbed to 3647 m, where they spent the night. In the morning, 24 subjects (6 women) had a Lake Louise Questionnaire score (LLS) ≥ 3 (AMS(+)), and 15 subjects (4 women) exhibited moderate-to-severe disease (LLS ≥ 5 = AMS(++)). At Alagna, Spo2 did not differ between the AMS(-) and AMS(+) subjects. At higher stations, all AMS(+) subjects exhibited a significantly lower Spo2 than did the AMS(-) subjects: at 3275 m, 85.4% vs 87.7%; resting at 3647 m, 84.5% vs 86.4%. The receiver operating characteristics curve analysis resulted in a rather poor discrimination between the AMS(-) subjects and all of the AMS(+) subjects. With the cutoff LLS ≥ 5, the sensitivity was 86.67%, the specificity was 82.25%, and the area under the curve was 0.88 (P < .0001) for Spo2 ≤ 84% at 3647 m. We conclude that AMS(+) subjects exhibit a more severe and prolonged oxygen desaturation than do AMS(-) subjects starting from the beginning of altitude exposure, but the predictive power of Spo2 is accurate only for AMS(++).

The effect of deep and awake tracheal extubation on turnover times and postoperative respiratory complications post adenoid-tonsillectomy

To the Editor, Tonsillectomies and adenoidectomies (T&As) are increasingly performed in an outpatient setting in order to increase time efficiency with rapid turnover between cases. Though Patel et al. showed no difference in postoperative respiratory complications between deep and awake tracheal extubation after T&A, there remains considerable debate amongst pediatric anesthesiologists concerning which extubation technique is safer and more efficient. We undertook a retrospective review of T&As in our institution to examine whether one method of tracheal extubation (deep or awake) saved time in the operating room and reduced turnover time. We also examined differences between extubation techniques relating to postoperative respiratory complications following T&A. After approval by the Committee on Human Research on March 29, 2012, we reviewed the charts of all\18-yr-old patients who underwent tonsillectomy, adenoidectomy, or both over a one-year period at the University of California San Francisco Benioff Children’s Hospital Ambulatory Surgery Center. Inclusion criteria included otherwise healthy patients with a primary surgical diagnosis of sleepdisordered breathing, chronic nasal congestion, recurrent tonsillitis, recurrent otitis media, or hearing loss/speech delay. A single surgeon performed all procedures and pediatric anesthesiologists, usually with a resident, provided the anesthesia. Patients were excluded if they had a condition known to increase the incidence of postoperative respiratory complications, including active upper respiratory tract infection, moderate to severe asthma, age less than two years, American Society of Anesthesiologists’ physical status III or above, cerebral palsy, craniofacial anomalies, chronic cardiopulmonary disease, a history of seizures, a history of prematurity, hypotonia, and failure to thrive. ‘‘Deep’’ tracheal extubation was presumed when anesthesia records showed an age-appropriate end-tidal anesthetic concentration C 1.0 minimum alveolar concentration at extubation. Three time intervals were recorded: time from surgery end to exiting the operating room (out of operating room time), time from exiting the operating room to re-entering with the next patient (turnover time), and time from the end of surgery to transfer of anesthesia care to postanesthesia care unit (PACU) personnel (anesthesia end time). Significant respiratory complications requiring an anesthesia provider’s assessment and/or management were collected from the PACU record, including airway obstruction requiring jaw thrust and/or airway adjuncts, pulse oximetry reading \ 93% for more than two minutes (prolonged oxygen desaturation), bronchospasm, laryngospasm, bleeding episodes, and need for tracheal reintubation or admission to the intensive care unit. Sixty-two of the 110 patients who met the inclusion criteria underwent deep tracheal extubation and 48 patients underwent awake extubation. There were no statistically significant differences between groups for age, weight, sex, or opioid received. Most (77%) patients were diagnosed with sleep-disordered breathing, though not all had formal sleep studies preoperatively. There were no statistically significant differences between extubation groups for out of operating room time (P = 0.14), anesthesia end time (P = 0.17), or turnover time (P = 0.59) (Figure). Two postoperative respiratory complications were observed in the PACU: one episode of laryngospasm in the awake extubation group and one episode of significant airway obstruction in the deep extubation group. S. K. Menda, MD G. A. Gregory, MD J. R. Feiner, MD M. S. Zwass, MD M. B. Ferschl, MD (&) University of California San Francisco, San Francisco, CA, USA e-mail: ferschlm@anesthesia.ucsf.edu

Effect of inhaled leukotriene C4 on cardiopulmonary function.

The changes in transcutaneous oxygen saturation (SaO2%) and airway responses to inhaled histamine and leukotriene C4 (LTC4) were examined in 10 asthmatic patients, and the effect of inhaled LTC4 (16 nmol) on cardiopulmonary hemodynamics was examined in seven nonasthmatic patients undergoing diagnostic cardiac catheterization. In asthmatic patients, LTC4 produced oxygen desaturation on two occasions. At a lower dose (2.0 nmol) LTC4 produced a marked fall in SaO2% that lasted less than 15 min and occurred in the absence of significant bronchoconstriction as measured by changes in FEV1, FEF25-75, and SGaw. At a higher cumulative dose (7 nmol), LTC4 caused prolonged oxygen desaturation with slow recovery and this was associated with significant bronchoconstriction. In contrast, histamine inhalation produced a single response with a fall in both FEV1 and SaO2% of short duration. The dose-response characteristics of LTC4 and histamine on oxygen desaturation in asthmatic patients appear to differ significantly and probably are dependent on relative sensitivities of pulmonary vascular and bronchial smooth muscle to these agonists. A single inhaled dose of LTC4 in nonasthmatic subjects produced a marked drop in PaO2 with significant increase in AaPO2, and this was associated with a mean (SEM) decrease in FEV1 of 14% (2.5) from the baseline. The mean cardiac output fell by 15% (3.4) without significant changes in blood pressure and heart rate. There was no electrocardiographic evidence of myocardial ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Immune hemolytic anemias

To determine the feasibility and safety of bilateral simultaneous vitreoretinal surgery in pediatric patients.International, multicenter, interventional, retrospective case series.Patients 17 years of age or younger from 24 centers worldwide who underwent immediate sequential bilateral vitreoretinal surgery (ISBVS)—defined as vitrectomy, scleral buckle, or lensectomy using the vitreous cutter—performed in both eyes sequentially during the same anesthesia session.Clinical history, surgical details and indications, time under anesthesia, and intraoperative and postoperative ophthalmic and systemic adverse events were reviewed.Ocular and systemic adverse events.A total of 344 surgeries from 172 ISBVS procedures in 167 patients were included in the study. The mean age of the cohort was 1.3±2.6 years. Nonexclusive indications for ISBVS were rapidly progressive disease (74.6%), systemic morbidity placing the child at high anesthesia risk (76.0%), and residence remote from surgery location (30.2%). The most common diagnoses were retinopathy of prematurity (ROP; 72.7% [P < 0.01]; stage 3, 4.8%; stage 4A, 44.4%; stage 4B, 22.4%; stage 5, 26.4%), familial exudative vitreoretinopathy (7.0%), abusive head trauma (4.1%), persistent fetal vasculature (3.5%), congenital cataract (1.7%), posterior capsular opacification (1.7%), rhegmatogenous retinal detachment (1.7%), congenital X-linked retinoschisis (1.2%), Norrie disease (2.3%), and viral retinitis (1.2%). Mean surgical time was 143±59 minutes for both eyes. Higher ROP stage correlated with longer surgical time (P = 0.02). There were no reported intraoperative ocular complications. During the immediate postoperative period, 2 eyes from different patients demonstrated unilateral vitreous hemorrhage (0.6%). No cases of endophthalmitis, choroidal hemorrhage, or hypotony occurred. Mean total anesthesia time was 203±87 minutes. There were no cases of anesthesia-related death, malignant hyperthermia, anaphylaxis, or cardiac event. There was 1 case of reintubation (0.6%) and 1 case of prolonged oxygen desaturation (0.6%). Mean follow-up after surgery was 103 weeks, and anatomic success and globe salvage rates were 89.8% and 98.0%, respectively.This study found ISBVS to be a feasible and safe treatment paradigm for pediatric patients with bilateral vitreoretinal pathologic features when repeated general anesthesia is undesirable or impractical.

Hypoxaemia after Surgery and Anaesthesia

THE significance of even transien't anoxia during anaesthesia has been w'idely recognised for many years but until recently the frequent occurrence and potendtiaJ danger of minor degrees of prolonged oxygen desaturation during the immediate post-operatlive period had not been appreciated. In 1962 however Nunn and Payne making use of the newer techniques of blood gas analysis demonstralted that some degree of arterial desaturation comimonly occurred after even 'the most trivial surgical procedures under general anaesthesia. S'ince then post-operative hypoxaemia has been intensively investigated and though the problem is not solved some of the relevant factors have been more clearly iden«tified. I't has of course been widely known since the work of Maier and Cournand in 1943 that lung surgery is associated with a substanytial reduction in arterial saturation which persists for severall dlays and even weeks after surgery, an observation later confirmed by Bjork and Hilty (1954) who drew attention to the significance of post-operative hypoxaemia in relation to the management of patients after open-chest surgery. Three years earl'ier Troell (195 1) had observed that 'major abdominal surgery was often followed by arterial desaturation both in patients who had breatlhed spontaneously and in those who had been artificially ventilated. In 1958 Gordh, Linderholm and Norlander who were the first workers in this field to use an oxygen electrode to determine oxygen tensions in blood obtained a mean fall in arterill oxygen tension of albout 16 mm.Hg. after major non-thoracic surgery in patients free from card'iovascular and respiratory disease.