Improved Long-Term Outcomes for Cardiac Surgery Patients Maintained on Volatile Anesthetics vs. Propofol
Cardiac surgery often involves a lengthy recovery period and, in some cases, intensive rehabilitation. Pain management during and post-surgery is an important aspect of recovery. Two main types of anesthetics used for cardiac surgery include propofol and “volatile” anesthetics.
Propofol is a hypnotic alkyl derivative that has a long history of use as a sedative. It was first identified as a drug candidate as early as 1973, with clinical trials following in 1977.[i] In 1986, AstraZeneca launched a propofol-based anesthetic that was branded as Diprivan, a name which is still occasionally used to refer to the drug. Propofol is an attractive choice for intravenous anesthesia given its rapid onset and reversible effects, as well as its ability to cross the blood-brain barrier which allows it to act on the inhibitory GABA-receptor pathway and dampen neurotransmission.[ii] Despite its initial appeal as a drug candidate, research suggests there can be moderate to severe consequences of prolonged use, including bradyarrhythmias, metabolic acidosis, rhabdomyolysis, hyperlipidemia and an enlarged or fatty liver.[iii]
A variety of different volatile or inhaled anesthetics are also currently used as clinical treatments, including drugs such as isoflurane, sevoflurane, and desflurane. In order to be considered a volatile anesthetic, a drug must meet several criteria: it should be relatively odorless, rapid in onset, safe, and potent, and should have a long shelf-life. Currently, there is no single ideal volatile anesthetic, and those that have been identified as having the greatest therapeutic potential are generally expensive.[iv] However, studies have found that inhaled agents have some cardioprotective effects that may improve surgical outcomes.[v][vi][vii]
Given the existence of various anesthetic options for maintaining patients undergoing cardiac surgery, researchers have sought to establish which options have the lowest short- and long- term mortality. A recently published review article by Bonnani et al.[viii] performed a systematic meta-analysis of randomized clinical trials comparing the effects of current volatile anesthetics compared to propofol in adults undergoing cardiac surgery. It was found that in comparison to propofol, volatile anesthetics resulted in significantly decreased instances of long-term mortality, myocardial infarction, cardiac troponin release, need for inotropic medications, and extubation time. Furthermore, patients in the volatile anesthetic group had a higher post-operative cardiac index. There were no significant findings to suggest differences in short-term mortality.
Given this conclusion, as well as the host of other studies that suggest a possible benefit for using volatile drugs on overall cardiac health, researchers are suggesting that it may be beneficial to consider using volatile drugs as a first choice for maintaining patients undergoing cardiac surgery.[ix]
References
[i] Foundation, Lasker. “Discovery and development of propofol, a widely used anesthetic”. The Lasker Foundation. Retrieved 25 July 2020.
[ii] Trapani G, Altomare C, Liso G, Sanna E, Biggio G. Propofol in anesthesia. Mechanism of action, structure-activity relationships, and drug delivery. Curr Med Chem. 2000;7(2):249-271. doi:10.2174/0929867003375335.
[iii] Propofol. National Center for Biotechnology Information. PubChem Compound Database. https://pubchem.ncbi.nlm.nih.gov/compound/propofol. Accessed August 16, 2020.
[iv] Medts RD, Hendrickx JFA. Sevoflurane or desflurane: Which one is more expensive? Can J Anesth. doi:10.1007/s12630-015-0530-9.
[v] Landoni G, Biondi-Zoccai GG, Zangrillo A, et al. Desflurane and sevoflurane in cardiac surgery: a meta-analysis of randomized clinical trials. J Cardiothorac Vasc Anesth 2007;21:502-511.
[vi] Uhlig C, Bluth T, Schwarz K, et al. Effects of volatile anesthetics on mortality and postoperative pulmonary and other complications in patients undergoing surgery: a systematic review and meta-analysis. Anesthesiology 2016;124:1230-1245.
[vii] Landoni G, Greco T, Biondi-Zoccai G, et al. Anaesthetic drugs and survival: a Bayesian network meta-analysis of randomized trials in cardiac surgery. Br J Anaesth 2013;111:886-896.
[viii] Bonanni A, Signori A, Alicino C, et al. Volatile Anesthetics versus Propofol for Cardiac Surgery with Cardiopulmonary Bypass. Anesthesiology. 2020;132(6):1429-1446. doi:10.1097/aln.0000000000003236.
[ix] Bosnjak Z. Faculty Opinions recommendation of Volatile Anesthetics versus Propofol for Cardiac Surgery with Cardiopulmonary Bypass: Meta-analysis of Randomized Trials. Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature. 2020. doi:10.3410/f.737617583.793573088.