High-resolution Pulse Oximetry Research Articles

Early screening of sleep disordered breathing in hospitalized stroke patients high-resolution pulse oximetry as prognostic and early intervention tools in patients with acute stroke and sleep apnea (HOPES TRIAL).

Sleep Disordered Breathing (SDB) has been shown to increase the risk of stroke and despite recommendations, routine evaluation for SDB in acute stroke is not consistent across institutions. The necessary logistics and expertise required to conduct sleep studies in hospitalized patients remain a significant barrier. This study aims to evaluate the feasibility of high-resolution pulse-oximetry (HRPO) for the screening of SDB in acute stroke. Secondarily, considering impact of SDB on acute stroke, we investigated whether SDB at acute stroke predicts functional outcome at discharge and at 3 months post-stroke. Patients with acute mild to moderate ischemic stroke underwent an overnight HRPO within 48h of admission. Patients were divided into SDB and no-SDB groups based on oxygen desaturations index(ODI > 10/h). Stepwise multivariate logistic regression analysis was applied to identify the relevant predictors of functional outcome (favorable [mRS 1-2 points] versus unfavorable [mrS > = 3 points]). Of the 142 consecutively screened patients, 96 were included in the analysis. Of these, 33/96 (34%) were identified as having SDB and were more likely to have unfavorable mRS scores as compared to those without SDB (odds ratio = 2.70, p-value = 0.032). HRPO may be a low-cost and easily administered screening method to detect SDB among patients hospitalized for acute ischemic stroke. Patients with SDB (as defined by ODI) have a higher burden of neurological deficits as compared to those without SDB during hospitalization.

0432 Estimating the Prevalence of Obesity Hypoventilation Syndrome in a Rural Appalachian Inpatient Cohort

Abstract Introduction Patients with Obstructive Sleep Apnea (OSA) and concomitant Obesity Hypoventilation Syndrome (OHS) have been shown to have excess morbidity and mortality and higher healthcare expenditure when compared with patients with OSA only. Despite this, OHS is typically underdiagnosed and untreated. These effects may be more pronounced in rural Appalachian patients in whom rates of obesity, cardiovascular disease, metabolic disease, smoking, and COPD exceed the national average, yet poverty and challenging geography undermine access to healthcare. Methods Eligible patients from Sept 2019-Jan 2022 were evaluated for sleep disordered breathing under our hospital sleep medicine program. These patients were screened using high-resolution pulse oximetry, or a portable Type III sleep testing device, or both. Their data was recorded onto our program registry and retrospectively analyzed. Results Of 1676 hospitalized patients evaluated through our hospital sleep medicine program, we determined that 1345 (80.2%) of patients had a BMI >/=30 kg/m2. Of these patients, 823 (49.1%) had an arterial or venous blood gas collected during screening. Excluding patients with other potential causes for hypercapnia, 178 (10.6%) met criteria for OHS. 119 (66.8% of this subgroup) met criteria for OSA/OHS, while 33% did not have OSA (AHI/ ODI< 5). Patients with OSA/OHS overlap in our cohort typically had mild OSA. Conclusion When compared estimates in urban populations, our cohort is underrepresented. As such, many more patients with potential OHS and OSA/OHS overlap are discharged home without any treatment or plan for follow-up. One possible solution is suggested by the fact that only 49.1% of our initial cohort had an arterial or venous blood gas (ABG/VBG) collected during the admission. We recommend additional screening with serum bicarbonate and subsequent blood gases as part of an inpatient screening program for OSA/OHS. Early identification of these patients may facilitate early treatment while in-hospital and help reduce health disparity. Support (if any)

How to interpret a negative high-resolution pulse oximetry in hospitalized patients screened for obstructive sleep apnea: an exploratory analysis.

Obstructive sleep apnea (OSA) is a highly prevalent disorder that often is unrecognized. Recently, a novel protocol for screening hospitalized patients for OSA resulted in early initiation of positive airway pressure (PAP) therapy and early post-discharge follow-up. The protocol utilizes a combination of high-resolution pulse oximetry (HRPO) and home sleep apnea tests (HSATs); the former has been well-validated in previous studies against HSAT and polysomnography. While a definitive treatment plan can be generated for patients with a positive HRPO for OSA, it is less clear how best to manage patients with a negative HRPO. A retrospective analysis of a registry of patients screened for OSA was conducted. Consecutive patients with HRPO-derived ODI (oxygen desaturation index) < 5/h who underwent same-night HRPO and HSAT were identified. The demographic and clinical characteristics of patients with ODI < 5/h and AHI (apnea hypopnea index) < 5/h were compared with patients with ODI < 5/h and AHI ≥ 5/h. The analysis revealed 190 patients with ODI < 5/h. Only 23 (12%) of these patients had AHI ≥ 5/h. When compared with patients who had ODI < 5/h and AHI < 5/h, there was no difference in most testing and patient characteristics. However, antiplatelet use and total time in minutes with saturation < 88% greater than 100min were associated with a higher likelihood of discordant ODI and AHI. HRPO-derived ODI has a low rate of false negativity. Clinicians should be aware of the possibility of a false negative ODI for patients with antiplatelet use and time with saturation < 88% greater than 100min and antiplatelet therapy.

0721 Correlation between Oxygen Desaturation Index and Apnea Hypopnea Index for Diagnosis of Obstructive Sleep Apnea

Abstract Introduction Obstructive sleep apnea (OSA) is diagnosed through polysomnography (PSG) which can be done in lab or outpatient. PSG is conventionally not approved by insurance companies’ in-patient which can result in delay in diagnosis and treatment of OSA. High resolution pulse oximetry (HRPO) done inpatient is easy to perform and calculates oxygen desaturation index (ODI) to asses’ nocturnal desaturations which solely, is insufficient for diagnoses of OSA according to current treatment guidelines. We hypothesize that there may be a correlation between ODI and apnea hypopnea index (AHI) which can facilitate in earlier diagnosis of OSA. Methods We conducted a retrospective chart review to compare patients who underwent HRPO resulting in a sleep medicine consult inpatient followed by polysomnography outpatient over a 2-year period at a tertiary care academic center. Demographic data, ODI, AHI and oxygen nadir levels were collected. Results Sixty-five patients (47 males, 18 females; mean age of 59.1 years) with suspected OSA underwent inpatient HRPO during their hospital stay, followed by a PSG in the outpatient setting. The strength of association between ODI and AHI was determined using a Pearson’s analysis after adjusting to a logarithmic scale. There was a statistically significant weakly positive association between ODI and AHI (Pearson correlation=0.33, p=0.008). Linear regression analysis demonstrated a predictive value of 0.419 (p=0.008) between AHI and ODI. However, there was no statistically significant predictive value between ODI and AHI when adjusted for age, sex, body mass index (BMI) and ethnicity (beta =0.169; p=0.330). This may be limited by small sample size. HRPO nadir oxygen saturation (NOS) also correlated with polysomnography NOS with a Pearson correlation coefficient of 0.353 (p=0.006). Linear regression analysis showed a predictive value beta of 0.149 (p=0.006). When adjusted for age, sex, BMI and race, beta was equal to 0.156 (p=0.007). Conclusion ODI calculated through HRPO may be correlated with AHI. NOS determined through HRPO is weakly positively predictive of NOS calculated through PSG. To initiate treatment of OSA sooner, HRPO may be considered for screening or diagnostic purposes. The correlation between ODI and AHI needs to establish further in randomized controlled setting. Support (If Any)

Addressing rural health disparity with a novel hospital sleep apnea screening: Precision of a high-resolution pulse oximeter in screening for sleep-disordered breathing.

High-resolution pulse oximetry (HRPO) may offer a low-cost and simple screening option for sleep-disordered breathing (SDB) that could be vitally important in rural areas with limited healthcare resources and specialty care. Our team hypothesized that application of this technology to a broad cohort of rural dwelling hospitalized individuals would demonstrate congruence similar to previous urban studies comparing HRPO to portable sleep monitors. This retrospective study was conducted at West Virginia University Hospital and compared indices obtained from HRPO with those obtained from a type III portable sleep monitor (PM) on the same night. A total of 365 individuals underwent evaluation. The mean oxygen desaturation index (18.8 ± 19.3 events/h) from the HRPO was slightly higher than the mean respiratory event index (16.0 ± 18.1 events/h, p ≤ 0.001) from the PM. ROC curves were developed for thresholds of apnea severity predicted by the screening program. The AUC values for all three thresholds exceeded 0.92 and for a respiratory event index (REI) of ≥ 30 was 0.965. Indices from the PM and HRPO demonstrated agreement in those individuals with screening suggestive of moderatetosevere disease. This study demonstrates that use of HRPO in screening for SDB in hospitalized patients from rural communities is as accurate as PM and may serve as a simple cost-effective tool to address sleep health disparities in these regions with significant health inequity. Our data extend previous findings by applying HRPO to a larger hospitalized cohort with highly prevalent cardiopulmonary disease.

Sleep Disordered Breathing in Hospitalized African-Americans

RationaleSleep-disordered breathing (SDB) is a common disorder in general population, with higher prevalence in population with comorbid cardiovascular disease, and yet it remains frequently undiagnosed. Prior published data show that hospitalized obese patients have a high incidence of unrecognized SDB. However, limited data exists on the incidence, prevalence, and impact of SDB in hospitalized obese African-American (AA) patients. This study was performed to better understand the burden of undiagnosed SDB in hospitalized AA patients and its implications on readmission. MethodsA total of 1243 consecutive obese AA patients admitted to medical or telemetry service were screened utilizing a screening questionnaire (STOP/STOPBANG) from October 2016 to October 2017. If the results of the screening questionnaire were positive, the patients were offered inpatient testing with either High Resolution Pulse Oximetry (HRPO), or a type 3 portable monitor (PM). SDB was suspected if the Oxygen Desaturation Index (ODI) or Apnea Hypopnea Index (AHI) ≥ 5. We collected 30-day readmission and emergency department (ED) visit data on all patients and requested a formal outpatient sleep study for patients identified as SDB positive. ResultsOf the 1243 AA patients screened, 852 (68.5%) patients screened positive for SDB. Of these high-risk screens, 538 (63.1%) patients underwent inpatient testing with either High Resolution Pulse Oximetry (HRPO) or PM. Of these 538 patients, 319 (59.3%) were found to have suspected obstructive sleep apnea (OSA) based on ODI/AHI >5. Mild SDB (AHI 5–14) was present in 149 (46.7%) patients; moderate (AHI 15–29) in 74 (23.2%) patients; and severe (AHI >30) in 96 (30.1%) patients. The patients with suspected SDB were educated and encouraged to get an out-patient polysomnogram (PSG) but only 32 (10.0%) returned to undergo a formal PSG. The 30-day readmission rate/ED visits for patient with SDB was 13.5% compared to 13.7% of patients without SDB. ConclusionThis is the largest SDB registry that included obese hospitalized AA patients in a tertiary care academic center and reveals a high prevalence of undiagnosed SDB in this cohort. Despite proactive screening and patient education only 3.8% (32/852) of patients returned post-discharge for formal polysomnography. The presence of SDB did not impact the 30-day readmission rate/ED visit rate in this cohort.

Undiagnosed OSA May Significantly Affect Outcomes in Adults Admitted for COPD in an Inner-City Hospital

COPD is the second most common cause of hospital admission in the United States. OSA is a highly prevalent and underdiagnosed condition that may affect the outcome of COPD. We hypothesized that presence of unrecognized and untreated OSA will increase hospital readmissions in patients admitted for COPD exacerbation. We reviewed patients admitted for COPD exacerbation from May 2017 through July 2018 who were also screened for previously unrecognized and untreated OSA with a sleep questionnaire, and who subsequently underwent a high-resolution pulse oximetry or portable sleep monitoring study. We compared the rates of 30-, 90-, and 180-day readmission or death across OSA categories and compared overall survival in patients with and without OSA. Of 380 patients admitted for COPD exacerbation, 256 were screened for OSA with a sleep questionnaire (snoring, tiredness during daytime, observed apnea, high BP). Of these, 238 underwent an overnight high-resolution pulse oximetry/portable sleep monitoring. Of the 238 total patients, 111 (46.6%) were found to have OSA; 28.6%had mild, 9.7%moderate, and 8.4%severe OSA. Baseline characteristics and demographics were compared between the cohorts of participants with OSA and without OSA and were similar except that patients with OSA had a higher mean BMI (33.9 vs30.3kg/m2) and an increased prevalence of heart failure (19.8%vs7.1%). For patients with COPD and mild OSA, odds of 30-day readmission were 2.05 times higher than for patients without OSA (32.4%vs18.9%). Additionally, odds of 30-day readmission were 6.68 times higher for patients with moderate OSA vspatients without OSA (60.9%vs18.9%) and 10.01 times high for patients with severe OSA vspatients without OSA (70%vs18.9%). Readmission rates were also greater at 90 and 180days. All-cause mortality was lower for patients without OSA than for patients with OSA (P< .01). The time to hospital readmission or death was shorter with greater OSA severity (P< .01). Patients hospitalized for COPD exacerbation and who have unrecognized OSA; 30-, 90-, and 180-day readmission rates; and 6-month mortality rates are higher than in those without OSA.

High-Resolution Pulse Oximetry and Titration of a Mandibular Advancement Device for Obstructive Sleep Apnea.

Background: To determine whether utilizing high-resolution pulse oximetry is a viable method for evaluating the successful titration of oral appliances for the treatment of obstructive sleep apnea (OSA) patients.Methods: Of 136 consecutive potentially eligible OSA patients, 133 were fitted with mandibular advancement devices (MADs), and 101 completed all phases of treatment. The vertical and horizontal dimensions of the appliances were adjusted based on three-nights with a high-resolution pulse oximeter during sleep and associated software after each adjustment.Results: Significant improvements in OSA severity were apparent in patients at all disease severity levels. High-resolution pulse oximetry provided reliable guidance in the titration process of mandibular advancement therapy. In 67 subjects (66.3%), a respiratory event index of <5 events/hour was achieved.Conclusions: OSA can be effectively treated with a MAD at any severity level, and high-resolution pulse oximetry provides critical information to guide oral appliance titration.

High-Resolution Pulse Oximetry (HRPO): A Cost-Effective Tool in Screening for Obstructive Sleep Apnea (OSA) in Acute Stroke and Predicting Outcome

IntroductionObstructive sleep apnea (OSA) is a well-known risk factor for stroke. This is attributed to multiple mechanisms such as endothelial dysfunction, atrial fibrillation, hypertension, and comorbid obesity. STOP questionnaire alone is unreliable to diagnose OSA and in-hospital sleep study is costly and can be technically challenging. We used high-resolution pulse oximetry (HRPO) to test the feasibility of screening for OSA and predicting outcome. MethodsData from 115 stroke patients who underwent HRPO was collected including Oxygen desaturation index (ODI) <4%, pulse rate, arterial oxygen saturation (SaO2), and time spent at SaO2 saturation <88%. We also collected data on various confounders. The outcomes measured were NIHSS (National Institutes of Health Stroke Scale), mRS (modified Rankin Score) on discharge, and discharge disposition. ResultsOverall 115 patients with valid HRPO data were included in the study. Mean age was 64±12years with 68% white, 22% black, and 10% Hispanic population. Of this cohort of 115 patients, 56% were males. Of the subjects enrolled 22 had atrial fibrillation, 27 had type 2 diabetes, 7 had resistant hypertension, and 7 had patient foramen ovale. Of the 115 patients, 75 patients were found to have ODI of >10 and the mean ODI was 29±30. The NIHSS on admission was 6.14±6.93 and on discharge was 4.46±4.59, mRS on discharge was 1.70±1.67 with 52% being discharged home, 43% to rehab, 2% nursing home, and 3% to long-term acute care facility. In this study, we show a strong association between atrial fibrillation and increasing ODI (P<.001, OR 1.01, CI 1.00-1.03). In addition, our study also shows an association between discharges outcome of rehab (more deficits leading to higher disability) versus discharge to home (lesser deficits) if ODI was ≤10 (P = 0.005, OR 3.76, CI 1.49-9.52). ConclusionsOur study showed that there is a significant burden of OSA in acute stroke patients. ODI emerged as a predictor of atrial fibrillation and discharge disposition in our study. HRPO may be a cost-effective tool to screen and evaluate for OSA in acute stroke patients.

Sleep Overnight Monitoring for Apnea in Patients Hospitalized with Heart Failure (SOMA-HF Study).

Sleep-disordered breathing (SDB) is highly prevalent in hospitalized patients with congestive heart failure (CHF) and the condition is diagnosed and treated in only a minority of these patients. Portable monitoring (PM) is a screening option, but due to costs and the expertise required, many hospitals may find it impractical to implement. We sought to test the utility of an alternative approach for screening hospitalized CHF patients for SDB, high-resolution pulse oximetry (HRPO). We conducted a prospective controlled trial of 125 consecutive patients admitted to the hospital with CHF. Simultaneous PM and HRPO for a single night was performed. All but one patient were monitored on breathing room air. The HRPO-derived ODI (oxygen desaturation index) was compared with PM-derived respiratory event index (REI) using both receiver operator characteristic (ROC) curve analysis and a Bland-Altman plot. Of 105 consecutive CHF patients with analyzable data, 61 (58%) were males with mean age of 64.9 ± 15.1 years and mean body mass index of 30.3 ± 8.3 kg/m2. Of the 105 patients, 10 (9.5%) had predominantly central sleep apnea (central events > 50% of the total events), although central events were noted in 42 (40%) of the patients. The ROC analysis showed an area under the curve of 0.89 for REI > 5 events/h. The Bland-Altman plot showed acceptable agreement with 95% limits of agreement between -28.5 to 33.7 events/h and little bias. We conclude that high-resolution pulse oximetry is a simple and cost-effective screening tool for SDB in CHF patients admitted to the hospital. Such screening approaches may be valuable for large-scale implementation and for the optimal design of interventional trials.

Recognition and Treatment of Sleep-Disordered Breathing in Obese Hospitalized Patients May Improve Survival. The HoSMed Database

PurposeSleep-disordered breathing is a common sleep disorder. Recent studies have shown that hospitalized obese patients have a high likelihood of unrecognized sleep-disordered breathing. However, no systematic large study has so far evaluated the outcomes of a screening program. This study provides demographic, clinical, and outcome data from a screening program at a tertiary care academic center. MethodsSubjects were 5062 patients screened from March 2013 to July 2016. Of these, 1410 underwent in-hospital overnight high-resolution pulse oximetry and 680 underwent polysomnography post discharge. Patients placed on positive airway therapy were followed in an ambulatory setting. ResultsThe mean age was 60.7 years (SD 15.2), and mean body mass index was 34.8 kg/m2 (SD 8.3), with 2477 (49.0%) males. Of the 1410 high-risk patients who underwent high-resolution plethysmography (HRPO), 1092 were sleep-disordered breathing positive (oxygen desaturation index [ODI] ≥5) and 680 high-risk patients underwent polysomnography. In this latter group, 585 (87%) were found to have sleep-disordered breathing (apnea-hypopnea index [AHI] >5). A receiver operating characteristic curve for ODI derived from HRPO plotted against AHI from polysomnography showed an area under the curve of 0.83 for an ODI of >5. Patients who were adherent to positive airway pressure therapy in the first 3 months had improved survival over a mean follow-up of 609 days compared with those who were nonadherent (P = .01). ConclusionThis large database of hospitalized patients confirms a high prevalence of undetected sleep-disordered breathing. Long-term follow-up of those compliant with treatment reveals a survival benefit.

High-Resolution Pulse Oximetry: Cost Effective Tool to Screen Sleep-Disordered Breathing in the Hospitalized Patients

Sleep Disordered breathing (SDB) is a highly prevalent disorder (6-13%) with significant cardiovascular implications. Hospitalized patients have significant under-diagnosed SDB. Under-recognition of this important co-morbidity may have deleterious effects including influence on re-admission rates. However, until recently there was no simple cost effective test to screen for SDB in the hospitalized patients. Recently, advances in plythesmography technology, most notably in ability to reduce averaging time and filter artifacts has allowed the possibility of having a cost effective strategy of screening SDB in hospitalized patients.

Markers for severity of illness associated with decreased snoring in toddlers born ELGA

To describe the prevalence of paediatric sleep disordered breathing (SDB) symptoms in extremely low gestational age infants and identify neonatal risk factors, including early exposure to hypoxia and hyperoxia. Patients <28 weeks gestation were monitored with high-resolution pulse oximetry. Hypoxia/hyperoxia variables were defined as percentage time of first 4 weeks of life that SaO(2) < 80% or SaO(2) > 98%, respectively. Parents completed part of the OSA-18 questionnaire for symptoms of SDB at 18-22 months. Logistic regression was used to test the association between risk factors and sleep symptoms. Of 182 patients recruited, 138 (76%) completed the questionnaire. The mean gestation was 26 weeks, and mean birth weight 887 grams. Loud snoring (21%) and restless sleep (24%) were the most prevalent symptoms. Female sex was associated with an increased risk of loud snoring (OR, 2.7; CI, 1.13-6.5). Prolonged mechanical ventilation, necrotizing enterocolitis and prolonged caffeine use, however, were inversely correlated with loud snoring. Neither neonatal hypoxia nor hyperoxia were associated with sleep symptoms. While the prevalence of sleep disordered breathing symptoms is similar to reported rates, we found a sex difference not previously reported. Interestingly, markers for severity of illness show a pattern of being protective against loud snoring.

Aspects of acute care in Sleep Medicine

Epidemiologic studies have repeatedly shown an association between obstructive sleep apnea (OSA) and cardiovascular endpoints including myocardial infarction, arrhythmias, congestive heart failure, stroke, and sudden cardiac death, even after adjustment for known cardiovascular risk factors. Gami et al. reviewed 112 reports of sudden death and found that almost half of the patients with polysomnographically confirmed OSA died during sleep hours (12 midnight to 6.00 am) compared to 21 % of those without OSA (RR 2.57) [1]. Of further interest was the fact that the risk of sudden death was related to disease severity of OSA. Anecdotal reports and case series of sudden cardiac arrhythmias and sudden cardiac death associated with severe OSA and hypoxemia have been reported during overnight polysomnographic recordings in the sleep labs [2]. The slow advent of inpatient polysomnography has lent more support to such claims. Recently, recurrent episodes of “cardiopulmonary arrest” were reported in a hospitalized patient with undiagnosed severe OSA during the night of the sleep study. Respiratory arrest and cerebral hypoxia during REM sleep were documented on polysomnography and no subsequent near arrest events were noted and possibly mitigated with the use of continuous positive airway pressure (CPAP) [3]. Another study looking at the prevalence of OSA in the medical intensive care unit reported 30to 90-s apneic periods followed by a prolonged period of flat/absent EEG activity among two patients one of whom arrested and died [4]. Whether OSA is an independent risk factor for sudden cardiac death requires further research, but high-resolution pulse oximetry or inpatient polysomnographic monitoring of acutely ill patients may help provide a clue. Sudden cardiac death (or near death) has been attributed to “depressed or failed arousal” followed by life-threatening hypoxemia in patients with severe OSA. In fact, this may be true among some obese patients who may average 50 or more severe cyclic desturations per average hour of sleep every night and may be at particular risk for acquired arousal failure [5]. Others have attributed the depressed arousal mechanism to sleep deprivation and fragmentation among hospitalized patients [6]. Narcotics, especially patient-controlled analgesia, spinal anesthesia, and sedatives can further increase or delay the arousal threshold and thereby compromise airway patency and survival among such patients. Undoubtedly, further studies are needed to understand the mechanisms of apnea termination and arousal response particularly among acutely ill hospitalized patients, postoperative patients, and patients receiving sedatives and narcotics. In the operating room, difficult intubation has been reported to occur eight times as often among OSA patients compared to controls [7]. Unanticipated transfers to ICU after surgery are more common among OSA patients as is the length of hospital and ICU stay [8, 9]. Up until recently, increased incidence of postoperative respiratory failure was not consistently reported among patients with OSA undergoing elective noncardiac surgery, mainly due to reasons of the study sample size, the definition of “respiratory failure” used for study purposes, as well as the study design (e.g., if the study was a quality improvement study). Recently, however, a large study of approximately 50,000 patients with OSA undergoing general and orthopedic surgery reported a fivefold increase in intubation and mechanical ventilation after surgery [10]. A recent meta-analysis of studies R. Kaw (*) Departments of Hospital Medicine and Outcomes Research, Anesthesiology, Cleveland Clinic, 9500 Euclid Avenue, Suite A-13, Cleveland, OH, USA e-mail: kawr@ccf.org

Low Oxygen Saturation Target Range is Associated with Increased Incidence of Intermittent Hypoxemia

To test the hypothesis that preterm infants randomized to a low vs high O(2) saturation target range have a higher incidence of intermittent hypoxemia. A subcohort of 115 preterm infants with high resolution pulse oximetry enrolled in the Surfactant, Positive Pressure, and Oxygenation Randomized Trial were randomized to low (85%-89%) or high (91%-95%) O(2) saturation target ranges. Oxygen saturation was monitored until 36 weeks postmenstrual age or until the infant was breathing room air without respiratory support for ≥72 hours. The low target O(2) saturation group had a higher rate of intermittent hypoxemia (≤80% for ≥10 seconds and ≤3 minutes) prior to 12 days and beyond 57 days of life (P < .05). The duration shortened (P < .0001) and the severity increased (P < .0001) with increasing postnatal age with no differences between target saturation groups. The higher rate of intermittent hypoxemia events in the low target group was associated with a time interval between events of <1 minute. A low O(2) saturation target was associated with an increased rate of intermittent hypoxemia events that was dependent on postnatal age. The duration and severity of events was comparable between target groups. Further investigation is needed to assess the role of intermittent hypoxemia and their timing on neonatal morbidity.

Early detection of inadvertent oesophageal intubation: pulse oximetry vs. capnography

The aim of our retrospective study was to evaluate the efficacy of routine pulse oximetry and capnometry for detection of oesophageal tube misplacement. Patients undergoing ENT interventions at our hospital are routinely monitored by ECG, arterial blood pressure by cuff, capnography, and pulse oximetry. Beat-to-beat values of Sao2 and CO2 waveform were recorded by a graphic printer connected to a microcomputer, ASA I patients were routinely preventilated with FIO2 = 0.3, and ASA II-III patients with FIO2 = 1.0. Anaesthesia was performed by junior anaesthesiologists under the close supervision of a resident. During a 16-month period, 1372 patients were anaesthetized. The records of 21 patients with accidental oesophageal tube misplacement were available for retrospective evaluation. Nine patients were preventilated with FIO2 = 0.3 (ASA I), 12 patients with FIO2 = 1.0 (ASA II-III). Rapid detection of oesophageal tube position as early as the first ventilation is possible by capnometry, because of the highly significant difference in end-tidal CO2 (0.2 +/- 0.2 vol%; tracheal intubation: 3.7 +/- 0.9 vol.%; P less than 0.0001). The present advanced pulse oximetry method does not permit differentiation between oesophageal and tracheal tube position within 30 s in patients preventilated with FIO2 = 1.0. Oesophageal misplacement was detectable within 7.5 +/- 0.9 s in patients preventilated with FIO2 = 0.3 due to a 2.1 +/- 0.8% decrease in Sao2 (P less than 0.001). Our results underscore the significance of capnometry for rapid detection of inadvertent oesophageal intubation. High-resolution pulse oximetry is a valuable supplement but not a substitute for capnometry.