Without evidence of benefit, an intervention should not be presumed to be beneficial or safe.

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ED procedural sedation of elderly patients: is it safe

ResearchBlogging.org

This is a study of the safety and success of EDPS (Emergency Department Procedural Sedation) in elderly patients.

When performed correctly, EDPS is a safe method to minimize pain and awareness of uncomfortable procedures [1-7]. The reported rates of adverse events in adults have ranged from 5% to 20%.[1]

What about in patients over 65, who may respond differently to sedation?

Is the incidence of side effects, or complications, similar in elderly patients?

Is the success rate of EDPS similar in elderly patients?

Standard monitoring and procedures, as required by the hospital’s EDPS protocol, were followed. In addition to an emergency physician, the EDPS protocol requires an emergency nurse assistant to be in the room to monitor the vital signs, pulse oximetry, and possible complications and to administer the ordered medications.[1]

Other facilities may have different requirements for elderly patients. Here, there was no change from the standard procedural sedation protocol for elderly patients.

To compare narcotic dosing, we used a previously published conversion table that equates intravenous morphine 5 mg, intravenous hydromorphone 1 mg, and intravenous fentanyl 100 μg [11].[1]

* The equianalgesic dose ratio of morphine to oxycodone is controversial. It appears to be between 1.5:1 and 2:1.
† Many tables quote the equianalgesic dose ratio of morphine to methadone as being 1:1, i.e., morphine 1mg po = methadone 1 mg po. This ratio was determined using single dose studies. In cancer pain, when multiple doses are required, the ratio of morphine to methadone becomes approximately 10:1, i.e., morphine 10 mg po = methadone 1 mg po.
‡ The equianalgesic dose ratio of morphine to fentanyl has not been accurately determined. It appears to be approximately 100:1, i.e., morphine 1 mg sc = fentanyl 10 µ (micrograms) sc. The equianalgesic ratio between parenteral fentanyl and transdermal fentanyl (patch) is also not well described, but appears to be approximately 1:1.[2]

This is a conversion for chronic opioid use for cancer pain, not for procedural sedation. However, the authors have documented a morphine:fentanyl ratio that differs dramatically from their source and from other sources.

Why list 5 mg morphine = 100 mcg fentanyl?

This conversion table lists both 1 mg morphine = 10 mcg fentanyl and5 mg morphine = 50 mcg fentanyl. These are the same and more consistent with other sources.

This raises some interesting questions.

Was fentanyl used more often/less often with elderly patients?

Does this conversion affect their results below?

There was a significant difference in the dose of medication given between the age groups, with the older age groups getting lower doses. Among patients in which propofol was the sole agent, the mean dose was 158 mg in the 18 to 49 age group, 124 mg in the 50 to 64 age group, and 106 mg in the at least 65 age group (P b .001). Among subjects who received both narcotic pain medication and propofol, the mean doses of propofol for each group were 172, 133, and 100 mg for age groups 18 to 49, 50 to 64, and at least 65 years, respectively (P = .002). The mean dose of narcotic in this group was not significantly different. With dosing in morphine equivalents, the age groups received 12, 10, and 9 mg, respectively (P = .707).[1]

Compared with the patients receiving propofol alone, patients receiving propofol with an opioid had a much more dramatic drop in the dose of propofol given as their age increased.

Were there differences between the rates of hypotension among those only receiving propofol and those receiving propofol with an opioid? Among all patients? More among elderly patients? Less among elderly patients?

Does this change the results of the study? Not unless the participants were using the mistaken equianalgesic conversion formula, but even that is only for a starting dose. Dosing with opioids and with sedatives is on a titrate to effect basis, not on a rigid protocol. It appears that the doses of propofol were titrated to effect, although it is possible that the dose was just lowered by some unknown conversion factor that ignored the response of the patient. It is possible, but it should not be probable with experienced trauma center nurses and doctors. Still, it does raise questions.

There was no significant difference in adverse events across ASA scores (P = .827). However, the rate of unsuccessful procedures (3.2% for ASA I, 2.3% for ASA II, 5.0% for ASA III, and 11.4% for ASA IV) differed significantly across ASA score (P = .042).[1]

American Society of Anesthesiologists (ASA) physical status classification for systemic disease . . . . classes
I (normal healthy patient),
II (mild systemic disease),
III (severe systemic disease), and
IV (severe systemic disease that is a constant threat to life)[1]

The rate of unsuccessful procedures may indicate that the medications were not as effectively titrated in elderly patients.

Was the dose too low in some of the elderly patients?

Did complications discourage higher doses due to appropriate titration of medication?

Since hernia reduction was more common with increasing age, and the failed procedure rate was highest for hernia reduction, was this an indication of where there was a problem with age and sedation safety?

How much of the difference in hypotension may be due to the elderly patients being sicker?

How much of the difference in the success of the procedure may be due to the elderly patients being sicker?

However, the dose of the sedative agent did decrease as age increased. These findings raise several questions: Are the physicians making a conscious decision to decrease the dose they are giving because the patients are older and therefore protecting against complications in this population thought to be at a higher risk? Or are the patients reaching the adequate level of sedation with a lower dose? Are the patients achieving the same sedation level as those younger?[1]

None of the elderly patients received midazolam (Versed). Was this due to a fear of causing hypotension?

We do not know.

While this appears to demonstrate similar safety and success when comparing elderly patients with younger patients, it would be nice to have more detailed data on the points I raised.

Footnotes:

[1] ED procedural sedation of elderly patients: is it safe?
Weaver CS, Terrell KM, Bassett R, Swiler W, Sandford B, Avery S, Perkins AJ.
Am J Emerg Med. 2011 Jun;29(5):541-4. Epub 2010 Apr 24.
PMID: 20825829 [PubMed – in process]

[2] Alberta hospice palliative care resource manual.
Division of Palliative Care. A. C. Board.
Pereira J, Bruera E.
(2001).
Free Full Text Download in PDF Format

Weaver CS, Terrell KM, Bassett R, Swiler W, Sandford B, Avery S, & Perkins AJ (2011). ED procedural sedation of elderly patients: is it safe? The American journal of emergency medicine, 29 (5), 541-4 PMID: 20825829

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