Incidence of Postoperative Oversedation 

May 26, 2023

Postoperative oversedation is a rare but dangerous event [1]. Complications including delirium, prolonged mechanical ventilation, pulmonary compromise, thromboembolism, and immunosuppression can occur because of oversedation [2, 3]. Oversedation may also impair medical staff’s ability to gauge patients’ pain levels [2] This may help explain the association researchers have noted between prolonged sedation and adverse neurologic and cardiopulmonary effects like respiration depression, hypotension, and depressed neurologic state [2]. While it is possible to reverse oversedation in some cases by administering opioid antagonists such as naloxone (Narcan), these substances also carry serious risks in the postoperative setting [4]. For instance, some patients may experience pain, followed by hypertension and tachycardia [4]. In light of these risks, the importance of understanding the incidence, contributing factors, and treatment options for postoperative oversedation could not be clearer. 

For one, patients’ risk factors may affect their likelihood of experiencing postoperative oversedation. Garrett and colleagues’ meta-analysis of 163,190 hospitalizations revealed multiple links between patient characteristics and oversedation, including age, sex, body mass index (BMI), renal insufficiency, liver insufficiency, and more [1]. Among these factors, they especially highlighted how concurrent administration of other medications with sedative qualities (including benzodiazepines, antidepressants, and gamma-aminobutyric acid analogue), older age (60+ years), and both low and high body mass index had a notable association with incidence of postoperative oversedation [5]. 

Although patient profile can influence the incidence of oversedation, other factors, particularly the anesthetic methods employed and subsequent monitoring provided by anesthesia teams, can also affect a patient’s risk of experiencing postoperative oversedation. To begin, the type of anesthetic administered during the surgery may have important implications for the depth of sedation experienced by patients. In their study of 56,275 patients, Deljou et al. found that deep sedation was likelier when patients received halogenated agents with higher solubility [6]. Additionally, patients who received those agents in conjunction with propofol experienced even higher risks of postoperative deep sedation [6]. 

The amount of anesthetic administered can also affect the occurrence of oversedation. After all, oversedation is caused by the accumulation of sedatives in inactive tissue that, upon emerging later on, cause a patient to experience dangerously deep levels of sedation [4]. Accordingly, by being more judicious in the volume of sedatives they administer but still giving patients enough such that the operation can go smoothly, medical professionals can avoid oversedation. Of course, this is easier said than done, especially given how the appropriate amount of sedative varies from patient to patient, but being wary of this possibility is a crucial first step to addressing it. 

In summary, multiple factors coalesce to determine a patient’s chances of suffering oversedation including but not limited to, individual risk factors, prior history of sedation, and the type of anesthesia that the patient receives. Incidence of postoperative oversedation varies by patient group. Thus, to prevent oversedation, researchers recommend that anesthesia teams assess each patient’s level of individual risk before the procedure [1]. Postoperative monitoring is also key. Studies indicate that, at least in some settings, oversedation continues outside of the predicted duration of activity [5]. Because patients may remain sedated anywhere from several minutes to several hours, if not more, after surgery, medical institutions should revise their monitoring protocols [5]. By taking an approach that incorporates both preventive and reactive elements, anesthetists have a greater chance of reducing the occurrence of negative patient outcomes brought on by postoperative oversedation. 


[1] J. Garrett et al., “Predicting opioid-induced oversedation in hospitalised patients: a multicentre observational study,” BMJ Open, vol. 11, no. 11, pp. 1-9, November 2021. [Online]. Available:  

[2] M. Kohler et al., “Pain management in critically ill patients: a review of multimodal treatment options,” Future Medicine, vol. 6, no. 6, pp. 591-602, May 2016. [Online]. Available:  

[3] J. R. Simpson, S. G. Katz, and T. V. Laan, “Oversedation in Postoperative Patients Requiring Ventilator Support Greater than 48 Hours: A 4-year National Surgical Quality Improvement Program-driven Project,” The American Surgeon, vol. 79, no. 10, pp. 1106-1110, October 2013. [Online]. Available:  

[4] S. C. Bagheri, “Chapter 3 – Anesthesia,” in Clinical Review of Oral and Maxillofacial Surgery. Amsterdam: Elsevier, Inc., 2014, ch.3, pp. 65-94. Accessed May 23, 2023. [Online]. Available:

[5] J. Garrett et al., “Timing of Oversedation Events Following Opiate Administration in Hospitalized Patients,” Journal of Clinical Medicine Research, vol. 13, no. 5, pp. 304-308, May 2021. [Online]. Available:  

[6] A. Deljou et al., “Anesthetic Management and Deep Sedation After Emergence From General Anesthesia: A Retrospective Cohort Study,” Anesthesia & Analgesia, vol. 136, no. 6, pp. 1154-1163, June 2023. [Online]. Available: