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We read with great interest the EMJ article by Bahreini and colleagues (published August 2020).1 The authors aimed to compare the relative efficacy and side effect profiles of sodium thiopental–fentanyl (TF) and ketamine–propofol (KP) when used for procedural sedation of 96 adult patients prior to undergoing a painful procedure in the emergency department setting. This randomised double-blind clinical trial quantitatively compared recovery time and both patient and provider satisfaction between the two treatment groups. Additionally, the study aimed to assess the prevalence of adverse effects occurring during recovery and patient recall of the procedure. The authors concluded that there was a statistically significant improvement in both patient and provider satisfaction and degree of procedure recall when using KP compared to TF. However, there was no statistically significant difference in recovery time or adverse effects between the treatment groups.
The authors discussed that the study was not adequately powered to assess the side effect profiles. However, using a systematic review of the effects of KP and propofol, it is possible to make comparisons with the current study regarding the KP side effect profile.2 In all cases, the occurrence of adverse events was greater in those studies included in the systemic review. For example, the POKER study reported that 14% of patients sedated with KP required an airway intervention 3 compared to only...
The authors discussed that the study was not adequately powered to assess the side effect profiles. However, using a systematic review of the effects of KP and propofol, it is possible to make comparisons with the current study regarding the KP side effect profile.2 In all cases, the occurrence of adverse events was greater in those studies included in the systemic review. For example, the POKER study reported that 14% of patients sedated with KP required an airway intervention 3 compared to only 8.5% in the current study. As expected, the disparity is even greater for infrequent adverse events. For example, the current study showed the rates of apnoeic and hypotensive episodes were 2.02% and 0% respectively, while the POKER study identified rates of 4% and 1%, respectively. This suggests that the side effect profile may be an underestimation for both treatment arms. It is important to note that there are slight variations in the initial dosing across these studies, which makes direct comparisons difficult. This is further complicated by the fact that additional doses were given to ‘maintain adequate sedation’ and that different sedation scales were used to achieve this. Regardless, further data collection is required to be able to draw conclusions on the secondary outcome of this study. This is particularly important since there is little differentiation between the efficacy of KP and TF, therefore a favourable side effect profile would indicate the preferable treatment option.
Additionally, research which is properly powered for adverse events is salient when discussing the side effect profile for TF, as sodium thiopental is known to cause serious cardiac dysfunction including arrhythmias and myocardial depression.4 However, the authors mention that the concerning respiratory complications of TF can be ‘overcome by careful titration’ and continued monitoring. Therefore, it is also important to discuss that there may be some disparity between the rate of adverse effects observed during a study versus that of regular clinical practice where time pressures and limited resources may apply. To account for this and reach a more practical representation, it may be beneficial to use a retroactive study to assess the presence of adverse events given the use of TF or KP sedation.
1. Bahreini M, Talebi Garekani M, Sotoodehnia M, Rasooli F. Comparison of the Efficacy of Ketamine-propofol versus Sodium Thiopental-Fentanyl in Sedation: A Randomised Clinical Trial [published online ahead of print, 2020 Aug 28]. Emerg Med J. 2020;emermed-2020-209542. doi:10.1136/emermed-2020-209542
2. Ghojazadeh M, Sanaie S, Paknezhad SP, Faghih SS, Soleimanpour H. Using Ketamine and Propofol for Procedural Sedation of Adults in the Emergency Department: A Systematic Review and Meta-Analysis. Adv Pharm Bull. 2019;9(1):5-11. doi:10.15171/apb.2019.002
3. Ferguson I, Bell A, Treston G, New L, Ding M, Holdgate A. Propofol or Ketofol for Procedural Sedation and Analgesia in Emergency Medicine-The POKER Study: A Randomized Double-Blind Clinical Trial. Ann Emerg Med. 2016;68(5):574-582.e1. doi:10.1016/j.annemergmed.2016.05.024
4. Uchida K, Shimizu H, Nagafuchi H, Yamamoto A, Ono S. Severe cardiac dysfunction induced by thiopental sodium. Pediatr Int. 2019;61(12):1270-1272. doi:10.1111/ped.14031