Oxygen Desaturation Events Research Articles

Assessing ventilatory control in infants at high risk of sleep disordered breathing: A study of infants with cleft lip and/or palate

Neonatal exposure to intermittent hypoxia results in altered ventilatory response to subsequent hypoxia in animal models. The effect of similar exposure in human infants is unknown. Our objective was to determine the impact of sleep disordered breathing (SDB) in early infancy on ventilatory response in infants. We recruited consecutive infants with cleft lip and/or palate (CL/P) to undergo ventilatory response testing using exposure to a hypoxic (15% O(2) ) gas mixture during sleep. This population is at high risk of SDB because of smaller airway caliber and abnormal palatal muscle attachments predisposing them to airway obstruction of ranging severity from birth. Ventilatory responses were compared between infants with a low apnea-hypopnea index (AHI; AHI < 15 events/hr) and a high AHI (AHI ≥ 15 events/hr). Testing was successfully completed in 22 of 23 infants who underwent testing at 4.4 ± 4.8 months. Infants with high AHI had lower weight z-scores, higher number of oxygen desaturation events during sleep, but similar oxygen saturation (S(p) O(2) ) nadir compared to infants with low AHI. The pattern of ventilatory response to hypoxia differed between the two groups; infants with high AHI had an earlier ventilatory decline and a blunted maximal ventilatory response to hypoxia. Infants with a high AHI use a different strategy to augment ventilation in response to hypoxia; while infants with a low AHI initially increased respiratory rate, tidal volume was the first parameter to increase in infants with high AHI. These results demonstrate that SDB in infancy is associated with altered ventilatory response to hypoxia.

Physiologic Effects of Retinopathy of Prematurity Screening Examinations

Preterm infants weighing less than 1500 g routinely undergo a series of eye examinations to screen for retinopathy of prematurity (ROP). While these examinations are important for the prevention of blindness, infants may suffer adverse physiologic events during and after the examination. The procedure includes administration of mydriatic eye drops that may be absorbed systemically and physical manipulation of the eye that is accompanied by stress and pain. The purpose of the study was to monitor changes in infant health status and adverse physiologic events in the 2 days after ROP eye screening. The study used 50 preterm infants with a mean gestational age of 32 weeks, undergoing their first ROP examination in a NICU located in a university medical center. This pilot study used a prospective, descriptive design. Physiologic changes and illness events were recorded before and for 2 days after the eye examination, using tools that tracked parameters of respiratory, cardiovascular, gastrointestinal, and neurological status. Data were collected directly from daily audits of medical records. McNemar's test for comparing paired proportions and the signed rank test were used for comparing significance of physiologic changes before and after the ROP eye examination. Apnea events increased significantly (P = .04) in the 24- to 48-hour period after the eye examination compared with apnea events before the eye examination. These results were based on 39 infants who were not receiving ventilator support. There was a significant difference in the frequency of oxygen desaturation events between infants with and without apnea (0-24 hours after examination, P < .002; 25-48 hours after examination, P < .001). There were no significant differences in heart rate, cyanosis, gastric residuals, or seizures after the eye examinations. The ROP examinations may be associated with increased apnea, a clinically significant problem. Nursing implications include careful monitoring of infants during and after ROP eye examinations, discharge teaching for caregivers, and continued research on nursing interventions to prevent adverse physiologic events.

Cerebral Oxygen Desaturation Events Assessed by Near-Infrared Spectroscopy During Shoulder Arthroscopy in the Beach Chair and Lateral Decubitus Positions

Cerebral Oxygen Desaturation Events Assessed by Near-Infrared Spectroscopy During Shoulder Arthroscopy in the Beach Chair and Lateral Decubitus Positions

Cerebral Oxygen Desaturation Events Assessed by Near-Infrared Spectroscopy During Shoulder Arthroscopy in the Beach Chair and Lateral Decubitus Positions

Cerebral Oxygen Desaturation Events Assessed by Near-Infrared Spectroscopy During Shoulder Arthroscopy in the Beach Chair and Lateral Decubitus Positions

Preserved Right Ventricular Function Despite Low Left Ventricular Ejection Fraction Predicts Good Survival after Ablation for Recurrent Ventricular Tachycardia

a 50% AHI reduction in those with a right lead. Central apnea events were reduced by 91% and 86% in left/right lead patients respectively. Oxygen desaturation events greater than 4% (ODI4) were also reduced. No arrythmias occurred as a result of stimulation, patients tolerated stimulation during sleep, and the incidence of arousals during sleep was reduced during therapy nights. Conclusion: Unilateral transvenous PNS is capable of achieving acute improvements in clinically relevant measures of sleep quality, regardless of the side upon which stimulation is applied. Further study with the right and left leads in a chronic and therefore stable setting is indicated.

Cerebral Oxygen Desaturation Events Assessed by Near-Infrared Spectroscopy During Shoulder Arthroscopy in the Beach Chair and Lateral Decubitus Positions

Patients undergoing shoulder surgery in the beach chair position (BCP) may be at risk for adverse neurologic events due to cerebral ischemia. In this investigation, we sought to determine the incidence of cerebral desaturation events (CDEs) during shoulder arthroscopy in the BCP or lateral decubitus position (LDP). Data were collected on 124 patients undergoing elective shoulder arthroscopy in the BCP (61 subjects) or LDP (63 subjects). Anesthetic management was standardized in all patients. Regional cerebral tissue oxygen saturation (Scto(2)) was quantified using near-infrared spectroscopy. Baseline heart rate, mean arterial blood pressure, arterial oxygen saturation, and Scto(2) were measured before patient positioning and then every 3 minutes for the duration of the surgical procedure. Scto(2) values below a critical threshold (> or = 20% decrease from baseline or absolute value < or = 55% for >15 seconds) were defined as a CDE and treated using a predetermined protocol. The number of CDEs and types of intervention used to treat low Scto(2) values were recorded. The association between intraoperative CDEs and impaired postoperative recovery was also assessed. Anesthetic management was similar in the BCP and LDP groups, with the exception of more interscalene blocks in the LDP group. Intraoperative hemodynamic variables did not differ between groups. Scto(2) values were lower in the BCP group throughout the intraoperative period (P < 0.0001). The incidence of CDEs was higher in the BCP group (80.3% vs 0% LDP group), as was the median number of CDEs per subject (4, range 0-38 vs 0, range 0-0 LDP group, all P < 0.0001). Among all study patients without interscalene blocks, a higher incidence of nausea (50.0% vs 6.7%, P = 0.0001) and vomiting (27.3% vs 3.3%, P = 0.011) was observed in subjects with intraoperative CDEs compared with subjects without CDEs. Shoulder surgery in the BCP is associated with significant reductions in cerebral oxygenation compared with values obtained in the LDP.

The use of epochs to stage sleep results in incorrect computer-generated AHI values

The objective of this study was to determine what impact the omission of respiratory events scored during wake epochs has on the generation of the apnea/hypopnea index (AHI) using computerised polysomnography (PSG). Sixty diagnostic PSG recordings were scored using the recommended method of sleep staging with epochs. In addition, absolute sleep scoring criteria was used to calculate the total sleep time (TST). The TST, respiratory events and AHI generated from both scoring methods were compared. The AHI from epoch scoring (AHI(EP)) was significantly less than that derived from absolute sleep staging (AHI(ABS)) [AHI(EP) = 15.8 events/hour (7.3, 38.2), AHI(ABS) = 18.8 events/hour (8.7, 40.2); p < 0.0001]. From a total of 8,820 legitimately scored respiratory events ≥10 s duration, 723 (8%) were excluded from the AHI(EP) calculation as they were identified as having occurred during wake, but 400 of these (57%) started in an epoch of wake and continued into epoch(s) of sleep. These omitted events were not trivial [median 16.6 s (13.0, 24.0)] and were frequently associated with oxygen desaturation events [median 4% (3.0, 7.0)] with a range of 3% to 39%. The use of arbitrarily defined epochs for sleep staging has a direct impact on legitimately scored respiratory events resulting in the systematically incorrect reporting of the AHI. This artefact is due to computerised data reduction excluding all respiratory events that are contained within an epoch(s) of wake as well as those that start in an epoch scored as wake.

Altitude Threshold for Sleep Disturbances During Exposure to Acute Hypobaric Hypoxia

To determine the altitude threshold for sleep disturbances during exposure to hypobaric hypoxia, 43 sea‐level (SL) residents (mean±SD, 22±4 yr) completed a one night sleep assessment at SL and during exposure to one of six levels of hypobaric hyoxia (2000 m (N=4), 3000 m (N=5), 3500 m (N=8), 4000 m (N=9), 4300 m (N=12), or 4500 m (N=5)). Each wore a pulse oximeter to measure arterial oxygen saturation (SaO2) and desaturation events (# of &gt; 6% drops in SaO2 for ≥ 8 sec) and a wrist motion detector to estimate sleep quality (awakenings/hr) and quantity (% sleep). Mean sleep SaO2 (%) decreased (P&lt;0.05) from SL (96±1) to 2000 m (92±1), 3000 m (89±2), 3500 m (83±4), 4000 m (73±4), 4300 m (72±4) and 4500 m (71±4). Desaturation events/hr did not increase from SL (0±1) at 2000 m (1±12), 3000 m (12±34) or 3500 m (5±4) but increased (P&lt;0.05) at 4000 m (34±48), 4300 m (56±50) and 4500 m (117±17). Awakenings/hr did not increase from SL (1±1) at 2000 m (1±2), 3000 m (2±2) m, or 3500 m (2±2) but increased (P&lt;0.05) at 4000 m (3±1), 4300 m (6±4) and 4500 m (5±3). The % sleep did not decrease from SL (95±6) at 2000 m (95±21), 3000 m (87±21) and 3500 m (88±22) but decreased (P&lt;0.05) at 4000 m (72±20), 4300 m (54±28) and 4500 m (63±25). These results suggest that although mean sleep SaO2 decreases at moderate altitudes, the threshold for significant sleep disturbances does not occur until 4000 m. Authors′ views; not official U.S. Army or DoD policy.

A Higher Incidence of Intermittent Hypoxemic Episodes Is Associated with Severe Retinopathy of Prematurity

Retinopathy of prematurity (ROP), a vasoproliferative disorder of the retina in preterm infants, is associated with multiple factors, including oxygenation level. We explored whether the common intermittent hypoxemic events in preterm infants are associated with the development of ROP. Oxygen desaturation events were quantified in 79 preterm infants (gestational age, 24 to 27-6/7 weeks) during the first 8 weeks of life. Infants were classified as requiring laser treatment for ROP versus having less severe or no ROP. A linear mixed model was used to study the association between the incidence of intermittent hypoxia and laser treatment of ROP, controlling for gestational age, sex, race, multiple births, and initial severity of illness. For all infants, hypoxemic events increased with postnatal age (P<.001). Controlling for all covariates, a higher incidence of oxygen desaturation events was found in the infants undergoing laser therapy for ROP (P<.001), males (P<.02), and infants of younger gestational age (P<.003). The incidence of hypoxemic events was higher in infants with ROP requiring laser therapy. Therapeutic strategies to optimize oxygenation in preterm infants should include minimization of desaturation episodes, which may in turn decrease serious morbidity in this high-risk population.

Characterization of cardiorespiratory events following gastroesophageal reflux in preterm infants

ObjectiveTo characterize cardiorespiratory events in preterm infants following both acid and non-acid GER as detected by pH and multiple intraluminal impedance (MII).Study DesignTwelve hour overnight studies were performed in 71 preterm infants (gestational age 29.4±3.0 wks, birth weight 1319±496 gm). Apnea ≥10 seconds in duration, bradycardia ≤80 bpm and oxygen desaturation ≤85% that occurred within 30 seconds after the initiation of GER were classified as associated with GER.Result12,957 cardiorespiratory events and 4164 GER episodes were documented. Less than 3% of all cardiorespiratory events were preceded by GER constituting 3.4% of apnea, 2.8% of oxygen desaturation and 2.9% of bradycardia events. GER did not prolong cardiorespiratory event duration or increase severity. In contrast, GER was associated with a shorter duration of oxygen desaturation events (7.8±4.6 vs 6.3±5.6 sec, p<.05).ConclusionGER is rarely associated with cardiorespiratory events, and has no detrimental effect on cardiorespiratory event duration or severity.

Anticholinergic Premedication for Flexible Bronchoscopy: A Randomized, Double-Blind, Placebo-Controlled Study of Atropine and Glycopyrrolate

Anticholinergic premedication is commonly used during flexible bronchoscopy, although the benefits are unproven and potential risks exist.We studied 1,000 patients undergoing diagnostic flexible bronchoscopy to investigate the efficacy and safety of atropine and glycopyrrolate. Patients received atropine (0.01 mg/kg; n = 339), glycopyrrolate (0.005 mg/kg; n = 336), or placebo (2 mL of normal saline solution; n = 325) IM before bronchoscopy in a randomized, double-blind fashion. Bronchoscopist- and patient-reported secretions, cough and patient discomfort, oxygen desaturation, procedure time, and procedure-related adverse events were compared among the groups.After adjusting for covariates, glycopyrrolate (p = 0.02), but not atropine (p = 0.064), was associated with reduced bronchoscopist-reported airway secretions. Neither drug was independently associated with patient-reported airway secretions or with bronchoscopist- or patient-reported cough or discomfort. Neither drug was independently associated with oxygen desaturation. Atropine was associated with a longer procedure time (p = 0.042). Rise in heart rate and BP was significantly greater with anticholinergics, particularly atropine, compared with placebo.Anticholinergic premedication may reduce airway secretions during flexible bronchoscopy but is not associated with any significant reduction in cough, patient discomfort, oxygen desaturation, or procedure time and is associated with greater hemodynamic fluctuations. Routine anticholinergic premedication may be unnecessary or even harmful during flexible bronchoscopy.

Validation study of a portable monitoring device for identifying OSA in a symptomatic patient population

Obstructive sleep apnoea syndrome (OSAS) is a common disorder associated with early atherosclerosis, diabetes mellitus, ischaemic heart disease and cerebrovascular disease. The gold standard for confirming OSAS is based on an attended overnight polysomnography (PSG) in a sleep laboratory; however lack of health-care resources creates long waiting times for patient access to this diagnostic test. This study evaluated the ability of a portable sleep-monitoring device to identify patients in Hong Kong with suspected OSAS. Patients with symptoms of OSAS were invited to use the ARES (apnoea risk evaluation system) concurrently with an attended inpatient PSG. Several sets of AHI were generated by the ARES provider based on different oxygen desaturation criteria and surrogate parameters of arousal. The results were compared against PSG to determine the optimal sensitivity and specificity. There were 141 patients who completed the study successfully. Results of AHI from the ARES study were presented in the order of different scoring criteria--4% oxygen desaturation alone, obstructive events with 3% oxygen desaturation and obstructive events with 1% desaturation plus surrogate arousal criteria. The sensitivity was 0.84 (95% confidence interval (CI): 0.77-0.90), 0.89 (95% CI: 0.89-0.94) and 0.97 (95% CI: 0.94-0.99), respectively. The specificity was 1, 1 and 0.63 (95% CI: 0.55-0.71), respectively. The receiver operating curve had an area of 0.96, 0.97 and 0.98, respectively. The kappa coefficient varied from 0.24 to 0.55 for agreement of severity between PSG and ARES. The likelihood ratio positive and the likelihood ratio negative were 2.61, infinity, infinity and 0.16, 0.11, 0.05, respectively, in the order of oxygen desaturation described earlier. The ARES device has reasonable sensitivity and specificity for diagnosing severe OSAS in symptomatic Chinese patients. There is moderate agreement between ARES and PSG in the diagnosis of severe disease, but less agreement in patients with mild/moderate disease.

Oxygen Saturation Improvement after Adenotonsillectomy in Children

The goal of this study was to establish whether adenotonsillectomy is effective on the severity of oxygen desaturation or improve oxygen saturation in children with sleep breathing disorders. Thirty-two children, aged 4-7 years, with clinical indication for adenotonsillectomy were enrolled in a non-controlled clinical trial. Pre- and postoperative nocturnal oxygen saturation monitoring was done and oxygen desaturation index as well as desaturation events were analyzed using Wilcoxon and paired Student's t-tests. Snoring was the most prevalent (87.5%) complaint before operation. The study revealed a significant improvement in the postoperative oxygen desaturation index (1.60 +/- 3.22) compared with the preoperative oxygen desaturation index (3.98 +/- 4.93) (p < 0.01). Oxygen desaturation events at the level of oxygen saturation 85-89% was significantly improved after operation (p < 0.01). No significant differences were seen in the desaturation events at the levels of oxygen saturation lower than 85%. Nocturnal oxygen saturation improves mildly after adenotonsillectomy in children with sleep breathing disorders.

Correlation between the Severity of Obstructive Sleep Apnea and Heart Rate Variability Indices

The risk of cardiovascular disease is known to be increased in obstructive sleep apnea syndrome (OSAS). Its mechanism can be explained by the observation that the sympathetic tone increases due to repetitive apneas accompanied by hypoxias and arousals during sleep. Heart rate variability (HRV) representing cardiac autonomic function is mediated by respiratory sinus arrhythmia, baroreflex-related fluctuation, and thermoregulation-related fluctuation. We evaluated the heart rate variability of OSAS patients during night to assess their relationship with the severity of the symptoms. We studied overnight polysomnographies of 59 male untreated OSAS patients with moderate to severe symptoms (mean age 45.4± 11.7 yr, apnea-hypopnea index [AHI]=43.2±23.4 events per hour, and AHI >15). Moderate (mean age 47.1±9.4 yr, AHI=15-30, n=22) and severe (mean age 44.5±12.9 yr, AHI >30, n=37) OSAS patients were compared for the indices derived from time and frequency domain analysis of HRV, AHI, oxygen desaturation event index (ODI), arousal index (ArI), and sleep parameters. As a result, the severe OSAS group showed higher mean powers of total frequency (TF) (p=0.012), very low frequency (VLF) (p= 0.038), and low frequency (LF) (p=0.002) than the moderate OSAS group. The LF/HF ratio (p=0.005) was higher in the severe group compared to that of the moderate group. On the time domain analysis, the HRV triangular index (p=0.026) of severe OSAS group was significantly higher. AHI was correlated best with the LF/HF ratio (rp=0.610, p<0.001) of all the HRV indices. According to the results, the frequency domain indices tended to reveal the difference between the groups better than time domain indices. Especially the LF/HF ratio was thought to be the most useful parameter to estimate the degree of AHI in OSAS patients.

Predisposing Factors of Sleep‐Disordered Breathing in Japanese Male Workers

The aim of this study was to elucidate the usable predisposing factors of sleep-disordered breathing (SDB) in the workplace. A total of 353 male workers who complained of SDB related symptoms such as witnessed snoring, recurrent awakening from sleep, urination during the night, morning headache, and excessive daytime sleepiness were included in the analysis. We examined hyoid-mental distance (HMD), modified Mallampati score (MMS), and the narrowness of the pharynx with tonsillar hypertrophy as the predisposing physical findings of SDB. We used the number of 3% or more oxygen desaturation events per hour (ODI3) as the indicator of SDB. The mean values (S.D.) of all subjects were 44.3 (8.9) yr (19-66 yr) of age, and 25.9 (3.8) Kg/m(2) body mass index (BMI). A significant difference in ODI3 was found between the HMD classes, and also between the subjects with and without tonsillar hypertrophy. Mean ODI3 adjusted for age, BMI, and alcohol consumption on the day of monitoring was high in the group of short HMD and the group of tonsillar hypertrophy (+). For MMS, though ODI3 did not appear to be significantly different, mean ODI3 was high in the MMS-IV. In conclusion, short HMD and tonsillar hypertrophy are the important findings predicting SDB identified by pulse oximetry. These findings would be beneficial in the workplace for selection of subjects who should be encouraged to undergo pulse oximetry for detection of SDB.

Adaptation to altitude as a vehicle for experiential learning of physiology by university undergraduates

In this article, an experiential learning activity is described in which 19 university undergraduates made experimental observations on each other to explore physiological adaptations to high altitude. Following 2 wk of didactic sessions and baseline data collection at sea level, the group ascended to a research station at 12,500-ft elevation. Here, teams of three to four students measured the maximal rate of oxygen uptake, cognitive function, hand and foot volume changes, reticulocyte count and hematocrit, urinary pH and 24-h urine volume, athletic performance, and nocturnal blood oxygen saturation. Their data allowed the students to quantify the effect of altitude on the oxygen cascade and to demonstrate the following altitude-related changes: 1) impaired performance on selected cognitive function tests, 2) mild peripheral edema, 3) rapid reticulocytosis, 4) urinary alkalinization and diuresis, 5) impaired aerobic but not anaerobic exercise performance, 6) inverse relationship between blood oxygen saturation and resting heart rate, and 7) regular periodic nocturnal oxygen desaturation events accompanied by heart rate accelerations. The students learned and applied basic statistical techniques to analyze their data, and each team summarized its results in the format of a scientific paper. The students were uniformly enthusiastic about the use of self-directed experimentation to explore the physiology of altitude adaptation and felt that they learned more from this course format than a control group of students felt that they learned from a physiology course taught by the same instructor in the standard classroom/laboratory format.

Stability of the Infant Car Seat Challenge and Risk Factors for Oxygen Desaturation Events

To explore the stability of the one-point Infant Car Seat Challenge and risk factors that may be associated with oxygen desaturation events. This descriptive, nonexperimental, observational study examined the responses of 49 premature infants during two 90-minute Infant Car Seat Challenges at a tertiary health care institution. Three Infant Car Seat Challenge outcomes were explored: (a) pass/fail rates following two Infant Car Seat Challenge observation periods, (b) oxygen saturation and desaturation patterns during two Infant Car Seat Challenges, and (c) the association between oxygen desaturation events and infants' chronological, gestational, and corrected gestational ages. The findings indicated that 86% of premature infants had stable results, 8% passed Infant Car Seat Challenge 1 but not Infant Car Seat Challenge 2, and 6% failed Infant Car Seat Challenge 1 and passed Infant Car Seat Challenge 2. In addition, the odds for oxygen desaturation events increased for infants born at less than or equal to 34 weeks gestation and hospitalized longer than 7 days. The Infant Car Seat Challenge success rate for identifying infants at risk for oxygen desaturation events was equal to or better than that of other screening tests for newborn medical conditions. The findings of this study will assist neonatal health care providers in making appropriate recommendations for infants' safe travel at discharge.

Does an oral appliance reduce palatal flutter and tongue base snoring?

Oral appliances are designed to treat snoring and sleep apnea by advancing the mandible and tongue. We test the hypothesis that an oral appliance affects palatal snoring as well as tongue base obstruction. Prospective observational cohort study. Sixty patients with a chief complaint of snoring with or without apnea were enrolled. Each patient underwent a home sleep test followed by 3 weeks sleeping with an oral appliance. Each patient then underwent a repeat home sleep test while using the device. There was a statistically significant improvement in the snores per hour (P = 0.0005), the maximum snoring loudness (P = 0.0001), average snoring loudness (P = 0.00001), and the percentage of palatal snoring (P = 0.0007). There was also a significant decrease in oxygen desaturation events (P = 0.003). This study suggests oral appliances may be effective treatment for both palatal and tongue base snoring.

The OxyArm™: A Supplemental Oxygen Delivery Device

Facemasks and nasal cannulae are used to provide supplemental oxygen to patients in the postoperative period after general anesthesia. These devices are associated with several patient complications, including aspiration, hypercarbia, and mechanical trauma. A new device, the OxyArm, is designed to eliminate these problems. It is an "open oxygen" system that does not require physical contact with the patient's face. In this clinical study we evaluated the OxyArm in the immediate postoperative period. Sixty patients received supplemental oxygen via the OxyArm for the first 8 min after tracheal extubation after general anesthesia. Oxygen saturation values were continuously recorded during 3 4-min time periods: 1) while breathing oxygen through an endotracheal tube before tracheal extubation, 2) while breathing oxygen delivered by the OxyArm at 4 L/min 4 min after tracheal extubation, and 3) while breathing oxygen delivered by the OxyArm at 2 L/min 8 min after tracheal extubation. There were no significant differences in oxygen saturation among the three time periods and no patient experienced an oxygen desaturation event less than 88%. Patients and clinicians praised the OxyArm for its comfort and ease of use, allowing nursing facial care without interrupting oxygen therapy. We conclude that the OxyArm delivers adequate levels of oxygen for most patients during the early postoperative period.

Propofol for Emergency Department Procedural Sedation and Analgesia: A Tale of Three Centers

To characterize propofol procedural sedation and analgesia (PSA) encounters for a large patient population at multiple emergency department (ED) sites. The authors sought to assess the frequency of respiratory and cardiovascular events during propofol PSA within these settings. This study was a prospective, descriptive series of a consecutive sample of ED patients receiving propofol for PSA at three study sites. Patients were monitored for PSA-related events, including predefined clinically relevant cardiovascular and respiratory events. Data collection was performed during PSA with a standardized data collection sheet unique to each site. Propofol was administered during PSA to 792 patients during the respective reporting period at each center. Indications for sedation included dislocation reduction (38%), cardioversion (10%), fracture reduction (35%), abscess incision and drainage (8%), computed tomography imaging (2%), and tube thoracostomy (1%). The cumulative rate of oxygen desaturation events for all study sites was 7.7% with a brief period of assisted ventilation with bag-valve mask in 3.9%. The cumulative rate of PSA-related hypotensive events was 3.5%. Increasing patient age and specific clinical procedure were clinical variables most associated with any propofol-related respiratory event. All PSA-related events resolved with supportive interventions during the PSA encounter. No patients required endotracheal intubation, prolonged observation, or admission for PSA-related complications. Propofol typically confers a deep sedation experience for ED PSA. The most common PSA events associated with propofol are respiratory related and appear consistent across these three practice settings. All propofol-related PSA events resolved with brief supportive interventions in the ED with no adverse sequelae.