Should capnography be routinely used during procedural sedation in the Emergency Department?
Date First Published:
April 25, 2011
Last Updated:
February 15, 2012
Report by:
Dr Fiona Burton, ST6 Emergency Medicine (Western Infirmary)
Search checked by:
Mr Philip Anderson, Western Infirmary
Three-Part Question:
In [a patient undergoing procedural sedation], does [the use of capnogrpahy] [reduce adverse respiratory events]?
Clinical Scenario:
A 35 year old man has a dislocated shoulder that will need to be reduced. He will require sedation and will be monitored with standard monitoring (ECG, BP, SpO2). You wonder if addition of capnography would be beneficial for the patient?
Search Strategy:
Ovid MEDLINE 1948 to November Week 2 2011
Search Details:
(sedation.mp) AND (Capnog$.mp or (end tidal adj2(carbon dioxide or CO2)))
The Cochrane library November 2011: MeSH descriptor Capnography.
The Cochrane library November 2011: MeSH descriptor Capnography.
Outcome:
202 papers were identified 9 of which were relevant.
Papers were excluded if they were not prospective studies and not undertaken in the Emergency Department (ED).
Papers were excluded if they were not prospective studies and not undertaken in the Emergency Department (ED).
Relevant Paper(s):
| Study Title | Patient Group | Study type (level of evidence) | Outcomes | Key results | Study Weaknesses |
|---|---|---|---|---|---|
| Conscious sedation in the emergency department: the value of capnography and pulse oximetry. Wright SW 1992 USA | 9 of 27 adults undergoing procedural sedation in an ED. Monitored with both standard monitoring and capnography. Respiratory depression defined as SpO2 <90%. |
Prospective observational | ETCO2 | 8/9 hypoxic patients had a rise in ETCO2 a few seconds before desaturation. | Small patient numbers. Nasal sampling used. |
| The value of end tidal CO2 monitoring when comparing three methods of conscious sedation for children undergoing painful procedures in the emergency department. Hart LS, Berns SD, Houck CS et al. 1997 USA | 8 of 42 children undergoing procedural sedation in an ED. SpO2 and ETCO2 were continuously recorded. Respiratory depression defined as SpO2<90% for >1 min, ETCO2 ≥50 mm Hg. |
Prospective observational | Hypercarbia only | 06-Aug | Small patient numbers. Nasal sampling |
| Hypercarbia and hypoxia | 02-Aug | ||||
| End-tidal carbon dioxide monitoring during procedural sedation. Miner JR, Heegaard W, Plummer D 2002 USA | 33 of 74 adults undergoing procedural sedation in an ED. Monitored with standard monitoring and capnography. Respiratory depression defined as: SpO2<90% for >1 min, ETCO2 ≥50 mm Hg, absent ETCO2 waveform. |
Prospective observational | SpO2≤90% | Nov-33 | Small patient numbers |
| Absent ETCO2 waveform | Nov-33 | ||||
| ETCO2 >50 mm Hg | 24/33 | ||||
| Does end-tidal carbon dioxide monitoring detect respiratory events prior to current sedation monitoring practices? Burton JH, Harrah JD, Germann, CA et al. 2006 USA | 20 of 59 adults and children (60 procedures) undergoing procedural sedation in an ED were monitored with standard monitoring and capnography. The clinical team were blinded. Acute respiratory event defined as: SpO2≤92%, Increase in supplemental O2, ETCO2 increase ≥10 mm Hg from baseline, ETCO2 ≤30 mm Hg, ETCO2 ≥50 mm Hg. |
Prospective observational | SpO2≤92% | 19/20 | Data recording. Convenience sample. Small patient numbers. Study terminated early. |
| Abnormal ETCO2 readings. | 16/19 hypoxic episodes | ||||
| ETCO2 findings documented before changes in SpO2 | 14/20 | ||||
| Capnography and depth of sedation during propofol sedation in children Anderson JL, Junkins E, Pribble C et al. 2007 USA | 125 children undergoing procedural sedation in an ED with propofol were monitored with standard monitoring and capnography. Respiratory events monitored were: Hypoxemia - SpO2<90%, Hypercarbia - ETCO2>50 mm Hg, ETCO2 increase >10 mm Hg from baseline, Apnoea: cessation of spontaneous ventilation for 30 s, Absent ETCO2 waveform and adverse airway events. |
Prospective observational | Hypoxemia | 6 episodes. | Convenience sample. Nasal sampling. |
| Hypercarbia: | 31 children. 7 required an intervention. | ||||
| Apnoea: | 5 patients became apnoeic. Capnography detected all 5 patients before pulse oximetry or clinical examination. | ||||
| Adverse airway event | 9 patients developed airway obstruction and 5 had a hypoxic event. Capnography identified 6 of the 9 before pulse oximetry or clinical examintaion. | ||||
| The utility of supplemental oxygen during emergency department procedural sedation and analgesia with midazolam and fentanyl: a randomized, controlled trial. Deitch K, Chudnofsky CR, Dominici P. 2007 USA | 39 of 80 adults and children undergoing procedural sedation in an ED monitored with standard monitoring and capnography. Respiratory depression defined as: SpO2<90%, ETCO2>50 mm Hg, ETCO2 change from baseline >10 mm Hg, loss of ETCO2 waveform. |
RCT | SpO2<90% | Nov-80 | Investigating the use of capnography was not the primary aim. Study terminated early after enrollment of 80 patients due to lower than expected incidence of hypoxia. |
| ETCO2 changes with hypoxia. | 07-Nov | ||||
| ETCO2 changes without hypoxia. | 28/80 | ||||
| Physician identification of respiratory depression. | 8/11 hypoxic patients and 0/28 who did not become hypoxic | ||||
| The utility of supplemental oxygen during emergency department procedural sedation with propofol: a randomized, controlled trial. Deitch K, Chudnofsky CR, Dominici P. 2008 USA | 110 adults undergoing procedural sedation in an ED. Patients were monitored with standard monitoring and capnography. Physicians were blinded. Respiratory depression was defined as SpO2<93%, ETCO2>50 mm Hg, ETCO2 change from baseline >10 mm Hg, Loss of ETCO2 waveform. |
RCT | Hypoxia | 25/100 | Investigation of the use of capnography was not the primary aim. Definition of hypoxia. |
| Absolute ETCO2 change≥10 mm Hg. | 18/25 patients who experienced hypoxia | ||||
| Clinical utility of absolute ETCO2 change≥10 mm Hg. | Sensitivity 72% (59% to 93%). Specificity 47% (36% to 58%) | ||||
| Physician identification of respiratory depression. | Physician identified respiratory depression in 23/25 patients who became hypoxic. Physician identified respiratory depression in 1/27 that met ETCO2 criteria but did not become hypoxic. | ||||
| Does end tidal CO2 monitoring during emergency department procedural sedation and analgesia with propofol decrease the incidence of hypoxic events? A Randomized Controlled Trial Deitch K, Miner J, Chudnofsky CR et al. 2010 USA | 132 adults undergoing procedural sedation in the ED were randomly assigned to study group (standard monitoring and capnography) or control group (standard monitoring and blinded capnography). Aimed to show 15% decrease in hypoxia from a presumed baseline of 20% when capnography used. 72 patients required in each arm.<br><br>Hypoxia defined as SpO2<93% for 15+ s. Respiratory depression defined as ETCO2≥50 mm Hg, ETCO2 increase or decrease from baseline ≥10%, Loss of waveform ≥15 s.<br><br>Capnography versus standard monitoring. |
RCT | Hypoxia | 17/68 vs 27/64 (p=0.035) | Underpowered. |
| Respiratory depression | All 44 patients who developed hypoxia first exhibited respiratory depression. | ||||
| Clinical utility of respiratory depression | 32 patients exhibited respiratory depression but did not develop hypoxia.<br><br>Sensitivity 100% [90% to 100%]<br><br>Specificity 64% (53% to 73%)). | ||||
| A comparative evaluation of capnometry versus pulse oximetry during procedural sedation and analgesia on room air. Sivilotti ML, Messenger DW, van Vlymen J, et al. 2010 Canada | 63 patients undergoing procedural sedation were monitored continuously with capnography and standard monitoring. Hypoxia defined as SpO2<92%. Abnormal capnometry defined as hypoventilation, ETCO2 >50 mm Hg, increase or decrease of 10 mm Hg from baseline, loss of waveform. |
RCT | Hypoxia | 36(57%) | Investigation of the use of capnography was not the primary aim. Study terminated early. Lack of information on study design. Not blinded to capnography. Data recording. |
| Abnormal capnometry | 30 (38%) patients showed abnormal capnography | ||||
| Hypoventilation | 21/36 hypoxic patients had abnormal capnography. 2/21 preceded desaturation.<br><br>19 patients exhibited hypoventilation. Hypoventilation did not precede desaturation in the12 patients in whom both events occurred. |
Author Commentary:
Deitch et al in 2010 published the only well-designed RCT with the primary aim of investigating the use of capnography during procedural sedation in the ED. This study demonstrated a statistically significant decrease in hypoxic events with the use of capnography. It suggested an ability to anticipate hypoxic events with capnography. The majority of the published evidence recognises that respiratory events do occur during procedural sedation and that there is a relatively high level of subclinical respiratory depression only evident with ETCO2 monitoring. They also recognise that a large number of these patients remain otherwise well. Most of the studies agree that those who become hypoxic exhibit ETCO2 changes before pulse oximetry changes. These changes in the ETCO2 could act as an early warning allowing the physician to assess the situation and take action as required. The paper by Sivilotti et al however, disagrees with the other studies with regards to the timing of changes in the ETCO2 and pulse oximetry. In their conclusion though, they state that this is only applicable in patients not receiving supplemental oxygen and it may in fact be a very useful monitor in patients receiving oxygen.
Bottom Line:
Capnography may provide early warning of ventilatory changes that could result in hypoxia.
References:
- Wright SW. Conscious sedation in the emergency department: the value of capnography and pulse oximetry.
- Hart LS, Berns SD, Houck CS et al.. The value of end tidal CO2 monitoring when comparing three methods of conscious sedation for children undergoing painful procedures in the emergency department.
- Miner JR, Heegaard W, Plummer D. End-tidal carbon dioxide monitoring during procedural sedation.
- Burton JH, Harrah JD, Germann, CA et al.. Does end-tidal carbon dioxide monitoring detect respiratory events prior to current sedation monitoring practices?
- Anderson JL, Junkins E, Pribble C et al.. Capnography and depth of sedation during propofol sedation in children
- Deitch K, Chudnofsky CR, Dominici P.. The utility of supplemental oxygen during emergency department procedural sedation and analgesia with midazolam and fentanyl: a randomized, controlled trial.
- Deitch K, Chudnofsky CR, Dominici P.. The utility of supplemental oxygen during emergency department procedural sedation with propofol: a randomized, controlled trial.
- Deitch K, Miner J, Chudnofsky CR et al.. Does end tidal CO2 monitoring during emergency department procedural sedation and analgesia with propofol decrease the incidence of hypoxic events? A Randomized Controlled Trial
- Sivilotti ML, Messenger DW, van Vlymen J, et al.. A comparative evaluation of capnometry versus pulse oximetry during procedural sedation and analgesia on room air.