Goldilocks and Propofol Dosage in Older Adults: Too Much, Too Little, or Just Right?

Michael J. Devinney MD, PhD; Miles Berger MD, PhD

Disclosures

J Am Geriatr Soc. 2021;69(8):2106-2109. 

In This Article

Are we Overdosing Older Adults? Should Anesthesiologists Reduce Propofol Induction Doses in Older Adults?

As discussed above, we believe it is premature to conclude that the data from Schonberger et al. demonstrate widespread "overdoses" of propofol in older adults. Nonetheless, these results and other recent reports raise the key question of whether relatively higher anesthetic induction and/or anesthetic maintenance dosage are associated with increased adverse events in older adults. If so, that would suggest the need for prospective studies to determine whether reducing anesthetic induction and/or maintenance dosage would improve outcomes in older surgical patients.

While such studies are being conducted, there are three reasons it would be premature to call for widespread reductions in anesthetic dosage for older adults. First, although "de-prescribing" is a common goal in geriatrics,[13] it does not quite apply to intraoperative anesthetic dosage in older adults. Unlike an outpatient geriatric setting in which avoiding the side effects of drugs may outweigh their potential long term benefits, the significant potential harms (including PTSD) associated with anesthetic under-dosage mean that reducing anesthetic dosage in the OR is not risk-free. Second, although other GABA-A receptors agonists like benzodiazepines are included Beers List of drugs to avoid in older adults,[14] performing surgery without administering GABA-A agonists such as propofol or inhaled anesthetics (which also act on other targets besides GABA-A receptors) is not a viable option, except during operations in which anesthesia can be provided solely by nerve blocks. Third, although some in vitro and animal studies have suggested neurotoxic effects of both propofol and inhaled anesthetics,[15,16] there is little evidence that these drugs have similar neurotoxicity in humans.[17] Indeed, many anesthetic drugs have been shown to produce toxic effects in vitro that do not occur in humans at clinically relevant doses.[18]

While it would be premature based on current data to suggest widespread changes to anesthetic dosage in older adults, this report serves two useful purposes moving forwards. First, it should serve as an impetus for anesthesiologists to carefully consider the doses of mind-altering drugs we are administering to older surgical patients, particularly since older patients are at increased risk of cognitive disturbances such as delirium following surgery.[19] Second, in order to improve clinical outcomes for older surgical patients, we first need to know exactly what our current clinical practice is. In this respect, Schonberger et al. have provided an important step forwards in defining current geriatric anesthesia practice across 36 different hospitals; future studies will help us define the best path forwards in anesthetic drug dosage for the more than 19 million older Americans who undergo surgery each year.[20]

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