Doi:10.1016/j.annemergmed.2007.11.040

AIRWAY/ORIGINAL RESEARCH The Utility of Supplemental Oxygen During Emergency Department Procedural Sedation With Propofol: A Randomized, Kenneth Deitch, DO From the Department of Emergency Medicine, Albert Einstein Medical Center, Philadelphia, PA.
Carl R. Chudnofsky, MD Paul Dominici, MD Study objective: We determine whether supplemental oxygen reduces the incidence of hypoxia by20% compared with breathing room air in adult study patients receiving propofol for emergencydepartment procedural sedation.
Methods: Patients were randomized to receive either supplemental oxygen or compressed air bynasal cannula at 3 L per minute. Physicians were blinded to the gas used and end tidal CO ( data. Respiratory depression was defined a priori as oxygen saturation less than or equal to 93%, an level of greater than or equal to 50 mm Hg, an absolute change from baseline of greater than or equal to 10 mm Hg, or loss of the ETCO waveform.
Results: Of the 110 patients analyzed, 56 received supplemental oxygen and 54 received room air.
Ten (18%) patients in the supplemental oxygen group and 15 (28%) patients in the compressed airgroup experienced hypoxia (P⫽.3, effect size⫽10%, 95% confidence interval ⫺24% to 7%). Twenty-seven patients (20 supplemental oxygen; 7 room air) met ETCO criteria for respiratory depression but did not become hypoxic. Physicians identified respiratory depression in 23 of 25 patients whodeveloped hypoxia compared with only 1 of 27 patients who met ETCO criteria for respiratory depression but who did not have hypoxia. One patient in the supplemental oxygen group experienceda transient arrhythmia and had a short apneic episode, both of which resolved spontaneously. Thepatient was admitted for observation.
Conclusion: Supplemental oxygen (3 L/minute) trended toward reducing hypoxia in adult studypatients; however, the 10% difference observed was not statistically significant and was below our apriori 20% threshold. Blinded capnography frequently identified respiratory depression undetected bythe treating physicians. [Ann Emerg Med. 2008;52:1-8.] 0196-0644/$-see front matterCopyright 2008 by the American College of Emergency Physicians.
doi:10.1016/j.annemergmed.2007.11.040 SEE EDITORIAL, P. 9.
undergoing deep sedation and suggests it be considered duringmoderate Although these recommendations seem intuitive, there is a paucity of information about the risks and benefits of supplemental oxygen during ED procedural sedation.
Throughout the past decade, the need to provide safe and The goal of supplemental oxygen is to increase oxygen effective procedural sedation has prompted an increasing reserves, thereby delaying or preventing the onset of hypoxia.
number of emergency department (ED) clinical trials and the However, increasing oxygen reserves is not without risk. It has introduction of new agents, techniques, and monitoring devices.
been shown that superoxygenated patients desaturate only after Yet, despite the knowledge gained by scientific study and prolonged apnea.This negates the use of pulse oximetry as an clinical experience, early detection of respiratory depression and early warning device for respiratory which is prevention of hypoxia remains a To reduce the concerning in light of the fact that emergency physicians rarely incidence of hypoxia, the American Society of Anesthesiology recognize respiratory depression in sedated patients who do not recommends the use of supplemental oxygen for patients Volume , .  : July  Annals of Emergency Medicine 1 Supplemental Oxygen During Propofol Sedation Deitch, Chudnofsky & Dominici analysis, we compared the relative accuracy of capnography in Editor's Capsule Summary
predicting hypoxia when the criterion of a 10-mm Hg absolute What is already known on this topic change in ETCO2 from baseline is narrowed to a 10% absolutechange in ETCO Though supplemental oxygen does not reduce the rate of 2 from baseline.
complicating hypoxia during sedation with midazolam MATERIALS AND METHODS
and fentanyl, it might do so for propofol, which is Study Design
typically used to induce a deeper level of sedation.
This was a prospective, randomized, double-blind, placebo- What question this study addressed controlled study conducted between November 2005 and Does 3L/min of oxygen by nasal cannula affect the October 2006. The institutional review board approved the frequency of oxygen desaturation during propofol Setting and Selection of Participants
What this study adds to our knowledge The study was performed in the ED at the Albert Einstein Desaturation occurred less frequently in the oxygen Medical Center, a Level I trauma center located in Philadelphia, group (18%) than control group (28%), though this PA. The ED features a well-established emergency medicine difference was smaller than the 20% difference deemed residency program and has an annual census of approximately important by the investigators.
75,000 patient visits.
How this might change clinical practice All patients older than 18 years and receiving propofol to facilitate a painful procedure were eligible for the study.
Although not definitive, this best available study suggests Enrollment occurred after the attending physician made the that adding 3 L per minute of supplemental oxygen decision that propofol would be safe and appropriate for during propofol sedation produces only a minor decrease procedural sedation. Consecutive patients who met inclusion in the risk of hypoxia, if any.
criteria were enrolled 24 hours a day, 7 days a week during the Research we'd like to see study period.
Replication of this study using 100% preoxygenation.
Patients were excluded if they had severe chronic obstructive pulmonary disease, long-term oxygen use, hemodynamicinstability, respiratory distress, pregnancy, allergy to any of the In the only other prospective study specifically designed to study drugs, or inability to provide informed consent.
evaluate the use of supplemental oxygen during ED procedural Written informed consent was obtained from each subject.
sedation and analgesia, we found that 2 L of supplemental Patients were randomized to receive either supplemental oxygen did not reduce the incidence of hypoxia by 20% in adult oxygen or room air at 3 L per minute by nasal cannula.
patients receiving midazolam and It is not clear Randomization was done with a computerized randomization whether these results can be extrapolated to other agents, table. Patients were assigned to their respective groups particularly propofol, which has a higher incidence of sequentially down a numbered list.
Procedural sedation was performed according to standard ED protocol. For this study, a research associate was present for the entire patient encounter and was responsible for ensuring If supplemental oxygen can limit the incidence or severity of appropriate patient selection, randomization, and data hypoxia during procedural sedation with propofol, without collection. The research associates are non– board certified hindering early recognition of respiratory depression, it should physicians who received specific training about procedural be incorporated into standard ED procedural sedation sedation, the study protocol, and data collection techniques, protocols. If supplemental oxygen prevents hypoxia but including identifying interventions by the treatment team to interferes with the physician's ability to detect respiratory improve oxygenation or ventilation.
depression, then additional precautions such as monitoring end After collection of baseline data, patients were randomized to tidal carbon dioxide (ETCO2) may be indicated. If supplemental receive room air or oxygen by nasal cannula at 3 L per minute.
oxygen does not reduce the incidence of hypoxia, its use should To ensure that the treatment team was blinded to the type of be abandoned.
gas being administered, the gases were delivered from one of 2 Goals of This Investigation. The goal of this study was to
identical D-tanks marked "A" and "B." The initial dose of determine whether supplemental oxygen delivered at 3 L per intravenous propofol was 1 to 1.5 mg/kg (ideal body weight).
minute by nasal cannula would reduce the incidence of hypoxia We chose this range according to our previous study, during by 20% in adult patients receiving propofol for procedural which we found that 1.0 mg/kg of propofol often produced sedation. We also evaluated whether physicians blinded to inadequate sedation. Subsequent doses of 0.5 mg/kg were capnographic data are able to recognize respiratory depression administered until the desired level of sedation was achieved.
during procedural sedation. Finally, in a preplanned secondary Once the patient was adequately sedated, the procedure was 2 Annals of Emergency Medicine Volume , .  : July  Deitch, Chudnofsky & Dominici Supplemental Oxygen During Propofol Sedation performed. Patients were closely monitored until back to significant bias. The institutional review board agreed that baseline alertness.
because individual staff members would not be identified in anyway, staff consent was not necessary.
Age, sex, medical history, medications, and allergies; type of Primary Data Analysis
procedure performed; and sedation and procedure times were Data analysis was performed with SPSS statistical software recorded by the research associates with a standardized data (SPSS, Inc., Chicago, IL). The incidence of hypoxia in each collection instrument. Procedure time was defined as the time group was compared with the 2-sample test of proportions. The from initial propofol administration until the patient returned number of interventions to treat respiratory depression in each to baseline alertness. The research associates measured alertness group was compared with the ␹2 test. Data are presented using levels with a 6-point Ramsay scale, with 1 indicating agitation 95% confidence intervals where appropriate. P⬍.05 was used to and 6 indicating unresponsiveness. This scale has been validated denote statistical significance. The study was powered to test the in ICU patients and used in a number of studies of ED procedural null hypothesis that there is no difference in the incidence of sedation and A Ramsay score was recorded at hypoxia in patients receiving supplemental oxygen and those baseline, 90 seconds after completion of drug administration, receiving room air during ED PSA using propofol. Previous and when it appeared the patient was back to baseline alertness.
PSA studies evaluating propofol have found that hypoxia occurs Vital signs (pulse rate, respiratory rate, and blood pressure), in 8% to 30% of For our power calculation, we oxygen saturation, and ETCO2 levels were recorded at baseline assumed that lowering the absolute incidence of hypoxic events and every 5 minutes until the patient returned to baseline by 20% would be clinically significant. Using Fisher's exact test alertness. ETCO2 was monitored with the NPB-Microstream 75 of 2 means (1-tailed test), with group 1 at 25% and group 2 at ETCO2 monitor (Nellcor Puritan Bennett Inc., Pleasanton, CA) 5%, a power of 80%, and an ␣ of 0.05, we calculated that the connected to a nasal cannula capable of delivering compressed study would require approximately 48 patients per group.
gases and fitted with an oral ETCO2 sampler to accommodatemouth breathers (Smart Capnoline O 2 Nasal Cannulas; Oridion Inc, Brussels, Belgium). The NPB-Microstream 75 Characteristics of Study Subjects
Research associates screened 175 patients during the 12- 2 monitor samples continuously at 50 mL per minute and can process up to 150 breaths/min. In an effort to determine month study period. Of these, 112 were enrolled in the study.
how well procedural sedation providers recognize respiratory Two patients were subsequently excluded because they received depression with standard monitoring techniques (ie, a nonstudy medication (etomidate) for sedation, leaving 110 observation, vital signs, pulse oximetry), the treatment team was patients for analysis The 2 groups were similar with kept blinded to ETCO respect to age, sex, and weight. Abscess incision and drainage and fracture and joint reduction accounted for all procedures.
There were no significant differences between the groups in the Respiratory depression was defined a priori as oxygen type or duration of procedures performed, the mean initial and saturation less than 93%, an ETCO2 level of greater than 50 mm total dose of propofol administered, the depth of sedation Hg, an absolute ETCO2 change from baseline of greater than 10 achieved, or the time to return to baseline alertness mm Hg, or loss of the ETCO2 waveform. These criteria were Ten patients in the supplemental oxygen group and 15 considered present if they occurred any time during the patients in the room air group experienced oxygen saturations procedure, regardless of their duration. When any of these less than 93% (P⫽.3; effect size⫽10%; 95% CI ⫺24% to 7%).
criteria occurred, the patient's vital signs, oxygen saturation, and Of the patients who met 1 or more criteria for respiratory ETCO2 level were recorded. The research associates also recorded depression, there were no differences between those patients these characteristics if any member of the treatment team receiving supplemental oxygen and those receiving room air verbalized that the patient was experiencing respiratory Twenty-seven of 110 (24.5%) study patients met 1 depression or provided an intervention to assist breathing, or more ETCO2 criteria for respiratory depression but did not including verbal or physical stimulation, airway realignment, use experience hypoxia Of the 25 patients whose oxygen of additional oxygen (from a wall source) or airway adjuncts, saturation decreased below 93%, 9 had ETCO2 changes assisted ventilation, or intubation. Other adverse events, consistent with respiratory depression before the onset of including hypotension, bradycardia, vomiting, prolonged ED hypoxia. provide a detailed summary of all ETCO2 stay (⬎2 hours after the procedure), or admissions, were also recorded on the data collection instruments.
Overall, physicians identified 24 of the 52 total patients who The treatment team was unaware that the research associates experienced 1 or more criteria of respiratory depression. In the were evaluating their (ie, the treatment team's) ability to subset of patients who became hypoxic, physicians identified 23 recognize respiratory depression with standard PSA monitoring.
of 25 patients, including all 10 patients in the supplemental ED personnel did not provide consent for the study because oxygen group and 13 of 15 patients in the room air group knowledge of this aspect of the protocol could result in In contrast, physicians detected respiratory depression Volume , .  : July  Annals of Emergency Medicine 3 Supplemental Oxygen During Propofol Sedation Deitch, Chudnofsky & Dominici Patients screened Patients enrolled Patients not enrolled Patients excluded (received etomidate) Depleted supplies* Met exclusion criteria Patients analyzed Physcian discretion** - 24Unable to consent - 6Chronic oxygen requirment - 4 Compressed air group Respiratory depression Respiratory depression ETCO2 changes only ETCO2 changes only Figure. Schematic representation of study results.
*Depleted supplies: Ran out of nasal cannula†Physician discretion: Physician felt that the patient was not a candidate for procedural sedation or propofolRD, Respiratory depression.
Table 1. Patient characteristics.
Table 2. Respiratory depression.
Room Air, Effect Size, % (nⴝ54) % (95% CI) Median age, y (range) Sex, female, No.
Total number of patients 22 (40) 8 (⫺5 to 31) Median weight, kg (range) meeting 1 or more Abscess incision and criteria* for respiratory Fracture reduction (%) Patients meeting both oxygen 6 (11) 3 (⫺16 to 45) Joint reduction (%) saturation and ETCO2 Mean initial propofol dose criteria* for respiratory Mean total propofol dose Patients meeting only oxygen 9 (16) 2 (⫺17 to 9) saturation criteria* for Median Ramsey scores respiratory depression (%) 90 s after the last dose Patients meeting only ETCO 7 (12)14 (⫺7 to 38) criteria* for respiratory medication (range) Median time from first dose *Respiratory depression: PO ⬍93%, ETCO ⬎50 mm Hg, an absolute ETCO of medication to return to change from baseline of ⬎10 mm Hg, or loss of the ETCO waveform.
baseline alertness, min(range) 57% to 77%]; positive predictive value [PPV]⫽32%, negative in only 1 of 27 patients who met 1 or more of the ETCO2 criteria predictive value [NPV]⫽67%). An absolute ETCO2 change from for respiratory depression but who did not become hypoxic.
baseline of greater than 10% would have identified 18 of the 25 An absolute ETCO2 change of greater than 10 mm Hg patients before they developed hypoxia (sensitivity 72% [95% identified 9 of 25 patients who experienced hypoxia (36% CI 59% to 93%], specificity 47% [95% CI 36% to 58%]; sensitive [95% CI 18% to 57%] and 68% specific [95% CI 4 Annals of Emergency Medicine Volume , .  : July  Deitch, Chudnofsky & Dominici Supplemental Oxygen During Propofol Sedation Table 3. ETCO changes.
smaller difference and enrolled more patients, we might have found a statistical difference.
Members of the clinical staff were blinded to the type of gas being administered and to the ETCO2 monitor, and they were ⬎50 mm Hg (number of unaware that their ability to recognize respiratory depression patients who became hypoxic) was being evaluated. Nevertheless, it is possible that knowing ⬎10 mm Hg above baseline the study was evaluating the use of supplemental oxygen (number of patients who heightened their awareness for identifying respiratory depression. However, the potential for heightened awareness ⬎10 mm Hg below baseline (number of patients who would be the same whether the patient was receiving supplemental oxygen or room air and therefore would not be Loss of the ETCO Waveform expected to affect the results.
(number of patients who The research associates were not blinded to the purpose of this study, which could have resulted in bias during data *Some patients met more than 1 criterion.
collection. However, the research associates made no patientcare decisions; they were present only to ensure protocoladherence and accurate data collection. In addition, all research One patient in the supplemental oxygen group received a associates participating in this study were physicians who brief period of assisted ventilation. The treating physician received training specifically directed at identifying a physician thought the patient became apneic, but there was no loss of the intervention for respiratory depression.
ETCO2 waveform indicative of apnea. The patient received asingle 1.05 mg/kg dose of propofol for incision and drainage of a buttock abscess; she was not given any other medications.
Supplemental oxygen (3 L/minute) trended toward reducing Three minutes after she received propofol, her oxygen saturation hypoxia in adult study patients; however, the 10% difference dropped to 85%, which was followed 6 minutes later by a 14- observed was not statistically significant and was below our a mm Hg increase in ETCO2. She also experienced a transient priori 20% threshold. To our knowledge, this is the first study (⬍10 seconds) sinus pause that resolved spontaneously and specifically designed to evaluate the use of supplemental oxygen postprocedure wheezing that resolved with 2 albuterol during procedural sedation that has shown a potential benefit to treatments and intravenous steroids. She was admitted for its use. We performed a previous study of procedural sedation observation and discharged the next day without further and analgesia with midazolam and fentanyl, in which the use of sequelae. Six patients (3 in each group) developed mild, supplemental oxygen did not lower incidence of transient hypotension (lowest systolic blood pressure 84 mm In our previous study, we found that 2 L of supplemental Hg). No patient in either group experienced bradycardia or oxygen by nasal cannula failed to reduce the incidence of vomiting, and no patients were intubated. There were no other hypoxia in patients receiving midazolam and fentanyl for adverse events.
procedural sedation and analgesia (13% in the supplementaloxygen group versus 14% in the room air group; P⫽This study was powered to detect a 20% We administered 3 L per minute of oxygen to the subjects in difference in the incidence of hypoxia, but only 13.9% of all the treatment group. Providing a higher concentration of patients in the study became hypoxic. A lower than expected supplemental oxygen may have resulted in a lower incidence of incidence of hypoxia weakened the study by making it impossible to demonstrate our a priori definition of clinical The mean initial and total propofol doses were slightly higher in the room air group which may have There are few other studies that support or discourage the contributed to the difference in the incidence of hypoxia use of supplemental oxygen during ED procedural. Three observed between the 2 groups.
previous studies have compared patients with and without We defined hypoxia as an oxygen saturation of less than supplemental oxygen and found conflicting results about the 93%. Although this level is higher than the traditional impact on respiratory depression and hypoxia. However, these definition of hypoxia (ie, 90%), we believe that an oxygen studies were neither blinded nor randomized and were not saturation of 93% would prompt most clinicians to provide designed to specifically evaluate the value of supplemental some intervention to improve oxygenation and or ventilation.
Using a lower oxygen saturation level may have increased the The current study was powered to detect a 20% difference in incidence of hypoxia.
the incidence of hypoxia between the 2 groups. We chose this Our study was powered to detect a 20% reduction in the difference according to our belief that most emergency physicians incidence of hypoxia in patients receiving supplemental oxygen would consider a 20% reduction in the incidence of hypoxia to be compared with patients breathing room air. Had we chosen a clinically significant and because it allowed us to design a study that Volume , .  : July  Annals of Emergency Medicine 5 Supplemental Oxygen During Propofol Sedation Deitch, Chudnofsky & Dominici Table 4. Patients with an absolute ETCO change from baseline of greater than 10 mm Hg without hypoxia.
Supplemental Oxygen Highest or Lowest Highest or Lowest Table 5. Patients with an absolute ETCO change from baseline of greater than 10 mm Hg with hypoxia.
Supplemental Oxygen Highest or Lowest Highest or Lowest required a reasonable number of subjects. As it turns out, we found below The missed hypoxic episodes in that study were that supplemental oxygen decreases the incidence of hypoxia by also short lived (⬍60 seconds) and mild (lowest oxygen 10%. Thus, according to our definition of clinical significance saturation was 87%). At that time, we surmised that the ED (20%) and subsequent power calculation, the study failed to show a staff simply missed these brief episodes of hypoxia or that the statistically significant difference in the incidence of hypoxia in physicians managing the cases decided to initially observe rather patients receiving supplemental oxygen compared with those than treat mild, transient hypoxia. Our study design does not breathing room air. Nevertheless, there appears to be a trend allow us to answer this question for either study but does toward a lower rate of hypoxia (10%) when supplemental oxygen is suggest that giving a patient continuous pulse oximetry does not given. This trend may be enough to prompt some clinicians to guarantee that the ED staff will identify all episodes of hypoxia.
administer supplemental oxygen when using propofol for In patients with unobstructed airways, hypoventilation procedural sedation. A larger study will be needed to confirm causes ETCO2 levels to whereas hypoventilation in the whether a difference of 10% truly exists.
presence of a developing airway obstruction produces a decrease Physicians identified the presence of respiratory depression in in ETCO2 or loss of the ETCO2 It has been suggested 23 of 25 patients who experienced hypoxia. In the 2 patients that an ETCO2 level of greater than 50 mm Hg, an absolute whose hypoxic events went unrecognized, the duration of ETCO2 change from baseline of greater than 10 mm Hg, or loss hypoxia was brief (⬍60 seconds) and the severity was mild of the ETCO2 waveform may identify patients at risk for (lowest oxygen saturation was 88%). In our previous study developing clinically significant respiratory using midazolam and fentanyl, physicians failed to identify signaling clinicians to intervene by stimulating breathing (for hypoxia in 3 of 11 patients whose oxygen saturation decreased increasing ETCO2), repositioning the airway (for decreasing 6 Annals of Emergency Medicine Volume , .  : July  Deitch, Chudnofsky & Dominici Supplemental Oxygen During Propofol Sedation Table 6. Physician recognition* of patients experiencing found that using an absolute ETCO 2 change from baseline of greater than 10% identified twice the number of patients who became hypoxic. We suggest identifying an ETCO2 "safe zone" by calculating the ETCO2 level 10% above and 10% below a patient's baseline. As long as the patient's ETCO2 remains in this Number of patients identified with respiratory safe zone, no intervention would be needed. An ETCO2 level depression/total number of patients who above or below this range would prompt the clinician to met 1 or more criteria for respiratory reposition the airway, stimulate the patient, and consider the need for other interventions as needed.
Number of patients identified with respiratory depression/total number of patients who Our study was not designed to evaluate the use of an ETCO2 met only oxygen saturation criteria for safe zone, but our data seem compelling, and we plan to test this respiratory depression concept in a controlled trial. Using an absolute change in ETCO2 Number of patients identified with respiratory from baseline of greater than 10% results in a lower specificity.
depression/total number of patients whomet both oxygen saturation and ETCO However, we believe that a greater sensitivity for identifying criteria for respiratory depression which patients will experience hypoxia outweighs the loss of Number of patients identified with respiratory depression/total number of patients who In the current study, 27 patients experienced ETCO2 changes met only ETCO criteria for respiratory consistent with respiratory depression but never became hypoxic Physicians identified respiratory depression in only 1 *The treatment team was given credit for identifying respiratory depression ifany member of the team verbalized that the patient was experiencing respiratory of these patients. This is similar to our previous study using depression or provided an intervention to assist breathing, including verbal or midazolam and fentanyl, in which blinded capnography physical stimulation, airway realignment, use of additional oxygen or airway ad- frequently identified respiratory depression undetected by the juncts, assisted ventilation, or intubation.
†Criteria for respiratory depression: Oxygen saturation of ⬍93%, ETCO level of treating However, the true significance of these ⬎50 mm Hg, an absolute ETCO change from baseline of ⬎10 mm Hg, or loss of ETCO2 changes in the absence of hypoxia is unclear because none the ETCO waveform.
of the patients in either of our studies who met only ETCO2criteria for respiratory depression had any sequelae.
Sedative hypnotics and opioids cause hypoventilation by 2 different mechanisms. Bradypneic hypoventilation, most ETCO2 or loss of the ETCO2 waveform), or withholding additional commonly observed with opioids, occurs when respiratory rate The ability of ETCO2 to identify respiratorydepression before the onset of hypoxia is supported by a number slows more than tidal volume decreases, which produces an of recent studies of ED procedural sedation.
increase in expiratory time and an increase in ETCO2Six of 36 In a study of children undergoing ED procedural sedation patients who met ETCO2 criteria for respiratory depression had with propofol for orthopedic reduction, Anderson et found bradypneic hypoventilation Hypopneic that capnography detected apnea in 5 of 5 patients and airway hypoventilation, most often associated with sedative hypnotic obstruction in 6 of 10 patients before clinical examination or use, occurs when tidal volume decreases more than respiratory pulse oximetry. In 2006, Burton et evaluated the ability of rate slows, resulting in low tidal volume breathing and anincrease in fractional dead space. When this occurs, ETCO 2 monitoring to detect adverse respiratory events before standard sedation monitoring practices. In this study, decrease or remain normal despite an increasing PaCO changes consistent with respiratory depression occurred in 17 of majority (30 of 36) of patients in our study who met ETCO2 20 patients (85%) who experienced an adverse respiratory event.
criteria for respiratory depression had hypopneic hypoventilation It is critical for physicians using 2 changes occurred 12 to 217 seconds before the onset of hypoxia or apnea in 14 of these patients and with the onset of sedative hypnotic agents to be familiar with these concepts hypoxia in 3 patients. In our study, we found that 9 of the 25 because a majority of patients experiencing respiratory patients (41%) who developed hypoxia had preceding ETCO depression will demonstrate a decreasing ETCO changes meeting our definition of respiratory depression It seems intuitive that depth of sedation plays an important Unfortunately, the capnography monitor used in our study role in the risk of respiratory depression during ED procedural does not allow us to provide exact intervals between ETCO sedation and analgesia. Comparison of our 2 studies evaluating changes and the onset of hypoxia.
supplemental oxygen seems to support this line of reasoning. In In an attempt to improve the sensitivity of ETCO our previous study using midazolam and fentanyl, the median for identifying which patients may become hypoxic, we Ramsey score was 4, and the incidence of hypoxia was 13.9%.
performed a secondary analysis comparing the sensitivity and In the current study using propofol, the median Ramsey score specificity of an absolute change in ETCO was 5, and the incidence of hypoxia was 22.7%. Although these 2 from baseline of greater than 10 mm Hg to an absolute change from baseline of studies were not designed to determine whether respiratory greater than 10% as a criterion for respiratory depression. We depression is more dependent on the agents used or the depth of Volume , .  : July  Annals of Emergency Medicine 7 Supplemental Oxygen During Propofol Sedation Deitch, Chudnofsky & Dominici sedation, the results do suggest that depth of sedation plays a 4. Patel R, Lenczyk M, Hannallah RS, et al. Age and the onset of role. We believe it would be prudent for clinicians desaturation in apnoeic children. Can J Anaesth. 1994;41:771-774.
administering procedural sedation to keep this in mind, 5. American Academy of Pediatrics, American Academy of Pediatric regardless of the agent(s) being administered.
Dentistry. Guidelines for monitoring and management of pediatric Overall, there were no significant differences in the incidence patients during and after sedation for diagnostic and therapeutic of adverse events between the 2 groups. One patient in the procedures: an update. Pediatrics. 2006;118:2587-2602.
supplemental oxygen group received assisted ventilation after 6. Green SM. Research advances in procedural sedation and analgesia. Ann Emerg Med. 2007;49:31-36.
experiencing a decrease in oxygen saturation, followed by an 7. Deitch K, Chudnofsky CR, Dominici P. The utility of supplemental increase in ETCO2. We believe this reflects an acute upper airway oxygen during emergency department procedural sedation and obstruction caused by placing an obese patient in the prone analgesia with midazolam and fentanyl: a randomized, controlled position, which significantly reduced her functional residual trial. Ann Emerg Med. 2007;49:1-8.
capacity and airway compliance. This led to acute oxygen 8. Miner JR, Biros MH, Heegaard W, et al. Bispectral electroencephalographic analysis of patients undergoing desaturation, followed over time by bradypneic hypoventilation procedural sedation in the emergency department. Acad Emerg and a gradual increase in ETCO2 9. Havel CJ, Strait R, Hennes H. A clinical trial of propofol vs.
Supervising editor: Steven M. Green, MD midazolam for procedural sedation in a pediatric emergencydepartment. Acad Emerg Med. 1999;6:989-997.
Author contributions: KD and CRC conceived the study and 10. Symington L, Thakore S. A review of the use of propofol for designed the trial. KD, CRC, and PD supervised the conduct of procedural sedation in the emergency department. Emerg Med J. the trial and data collection. KD, CRC, and PD managed the data, including quality control. PD provided statistical advice 11. De Jonghe B, Cook D, Appere-DeVecchi C, et al. Using and understanding sedation scoring systems: a systematic review.
on study design and analyzed the data. KD drafted the article.
Intensive Care Med. 2000;26:275-285.
CRC provided editorial support and contributed substantially to 12. Miner JR, Biros M, Krieg S, et al. Randomized controlled trial of its revisions. KD takes responsibility for the paper as a whole.
propofol versus methohexital for procedural sedation during Funding and support: By Annals policy, all authors are required fracture and dislocation reduction in the emergency department.
Acad Emerg Med. 2003;10:931-937.
to disclose any and all commercial, financial, and other 13. Bassett KE, Anderson JL, Pribble CG, et al. Propofol for relationships in any way related to the subject of this article, procedural sedation in children in the emergency department. Ann that may create any potential conflict of interest. The authors Emerg Med. 2003;42:773-782.
have stated that no such relationships exist. See the 14. Taylor DM, O'Brien D, Ritchie P, et al. Propofol versus Manuscript Submission Agreement in this issue for examples midazolam/fentanyl for reduction of anterior shoulder dislocation.
of specific conflicts covered by this statement.
Acad Emerg Med. 2005;2:13-19.
15. Godambe SA, Elliot V, Matheny D, et al. Comparison of propofol/ Publication dates: Received for publication October 3, 2007.
fentanyl versus ketamine/midazolam for brief orthopaedic Revisions received November 6, 2007, and November 8, procedural sedation in a pediatric emergency department.
2007. Accepted for publication November 18, 2007. Available online March 4, 2008.
16. Guenther-Skokan E, Pribble C, Bassett KE, et al. Use of propofol sedation in a pediatric emergency department: a prospective Earn CME Credit: Continuing Medical Education for this article study. Clin Pediatr (Phila). 2001;40:663-671.
17. Burton JH, Miner JR, Shipley ER, et al. Propofol for emergency department procedural sedation and analgesia: a tale of three Reprints not available from the authors.
centers. Acad Emerg Med. 2006;13:24-30.
Address for correspondence: Kenneth Deitch, DO, Department 18. Miner JR, Heegaard W, Plummer D. End-tidal carbon dioxide of Emergency Medicine, Albert Einstein Medical Center, monitoring during procedural sedation. Acad Emerg Med. 2002;9:275-280.
Korman B-6, 5501 Old York Road, Philadelphia, PA 19141; 19. Friesen RH, Alswang M. End-tidal CO monitoring via nasal 215-456-6679; E-mail cannulae in a pediatric emergency department: a prospectivestudy. Clin Pediatr (Phila). 2001;40:663-671.
20. McNulty SE, Roy J, Torjman M, et al. Relationship between arterial carbon dioxide and end -tidal carbon dioxide when a nasal 1. Chudnofsky CR, Lozon M. Sedation and analgesia for procedures.
sampling port is used. J Clin Monit. 1990;6:93-98.
Rosen P, Marx JA, Hockberger RS, et al, eds. Rosen's Emergency 21. Anderson JL, Junkins E, Pribble C, et al. Capnography and depth Medicine. 6th ed. St. Louis, MO: Mosby Year Book; 2006:2938- of sedation during propofol sedation in children. Ann Emerg Med. 2. American Society of Anesthesiology. Practice guidelines for 22. Burton JH, Harrah JD, Germann CA, et al. Does end-tidal carbon sedation and analgesia by non-anesthesiologists. Anesthesiology. dioxide monitoring detect respiratory events prior to current sedation monitoring practices? Acad Emerg Med. 2006;13:500- 3. Jense HG, Dubin SA, Silverstein PI, et al. Effect of obesity on safe duration of apnea in anesthetized humans. Anesth Analg. 1991; 23. Krauss B, Hess DR. Capnography for procedural sedation in the emergency department. Ann Emerg Med. 2007;50:172-181.
8 Annals of Emergency Medicine Volume , .  : July 

Source: http://emottawa.ca/assets_secure/journal_club/articles/March_1_Deitch%202008%20Ann%20Emerg%20Med%20Supplemental%20oxygen%20during%20propofol%20sedation.pdf