Bedworth, N

Breedon, P

Hewson, D

Sprinks, J

Worcester, F

Nottingham Trent Institutional Repository (IRep)

Patient-maintained propofol sedation for orthopaedic surgery: Patient variability in system use   David Hewson1, Nigel Bedforth2, James Sprinks3, Philip Breedon4 & Frank Worcester51Nottingham University Hospitals NHS Trust, Nottingham, UK, NG7 2UH, 2Division of Clinical Neuroscience, School of Medicine, University of Nottingham, Nottingham, UK, NG7 2UH,  3,4,5 Medical Design Research Group, School of Science and Technology, Nottingham Trent University, Nottingham, UK, NG1 4FQ.IntroductionOver 800,000 operations are performed annually in the UK in the presence of an anaesthetist but without using general anaesthesia (Sury et al., 2014). A substantial number of patients experience anxiety when undergoing awake procedures (Mitchell, 2009). A variety of techniques have been shown to be effective at reducing procedural anxiety, including pharmacological sedation (Mackenzie, 1996).Target controlled infusion (TCI) of propofol, under the direction of an anaesthetist, is a popular choice for intra-operative sedation because of the drug’s favourable pharmacokinetic profile; this is how the drug is adsorbed, distributed, metabolised and excreted by the body (Schnider et al., 1998). However, anaesthetists have been shown to be inaccurate judges of pre-operative patient anxiety (Badner et al, 1990; Fekrat et al., 2006). This could result in either insufficient or excessive dosing of pharmacological sedation in relation to the actual requirements of individual patients. One possibility for overcoming this is allowing patients control over their depth of sedation.Patient-maintained propofol sedation has been previously tested in endoscopy (Stonell et al., 2006; Campbell et al., 2004), dental (Leitch et al., 2003; 2004) and outpatient surgical (Yun et al., 2008; Alhashemi & Kaki, 2006) settings. While this research has reported back favourably in terms of sedation concentration, patient recovery time and anxiety levels, to date there has not been a truly human-centred approach to the problem that fully considers the opinion and role of the patient within the system.Methodology• 26 patients  presenting for elective lower limb orthopaedic surgery under regional anaesthesia at Nottingham University Hospitals NHS Trust took part• All expressed a pre-operative preference for surgery to be performed under sedation• Patients were given a hand-held button triggering an audible beep when pressed, indicating a request for deepening of sedation • Subjects were told: “You will be started on a background level of sedation” and “If you feel anxious or want to be more sleepy, press your button to increase the sedation”• On hearing a beep indicating a button-press, the study investigator manually altered the effect-site target of the propofol infusion according to a standardised protocol• Repeat button-presses were ignored until the calculated effect-site concentration was equal to the target (i.e. the lockout period was equal to the equilibration time)• After recovery from sedation, a questionnaire was administered seeking feedback on the use of the button and satisfaction with sedation  00.511.522.50 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120Effect-site concentration  (g ml-1)Time (minutes)4 types of patient behaviour:• Patient 1 (dotted line): Appeared anxious pre-operation in the anaesthetic room, and therefore chose to obtain a relatively deep level of sedation as soon as given the button to press • Patient 2 (solid line): Initially chose not to press the button when first available, but due to associated noise decided to deepen their sedation (between 10-15 minutes)• Patient 3 (dashed line): Button usage was the most regular throughout the surgery – achieving a relatively steady state of sedation throughout • Patient 4 (double line): Patient appeared relaxed for the majority of the surgery, and did not press the button until a major part of the surgery commenced (~45 minutes) Results Conclusions• Overall patients liked having control over their own sedation, were happy with their sedation level, and would use the same sedation technique again • System provided a degree of empowerment; patients found it reassuring to be able to control their level of sedation (even though ~50% chose not to use the button)• Lack of negative responses - this is perhaps surprising considering the lock-out period of button, and the associated unsuccessful button presses• Although feedback from the patients suggests a strong positive consensus, this did not translate to uniform behaviour when using the system• Pre-op anxiety, the stage of the operation, environmental effects (noise, vibrations etc.), and sensitivity to propofol can all influence the number and timing of sedation requests• Patients’ pre-operative anxiety could inform the baseline concentration of the sedation• If patient-maintained propofol sedation is to be successfully adopted as an alternative to anaesthetist-led practices, the system needs to be robust to the different ways patients’ use itReferencesAlhashemi, J. A., & Kaki, A. M. (2006). Anesthesiologist-controlled versus patient-controlled propofol sedation for shockwave lithotripsy. Canadian Journal of Anaesthesia, 53(5), 449.Badner, N. H., Nielson, W. R., Munk, S., Kwiatkowska, C., & Gelb, A. W. (1990). Preoperative anxiety: detection and contributing factors. Canadian Journal of Anaesthesia, 37(4), 444.Campbell, L., Imrie, G., Doherty, P., Porteous, C., Millar, K., Kenny, G. N. C., & Fletcher, G. (2004). Patient maintained sedation for colonoscopy using a target controlled infusion of propofol. Anaesthesia, 59(2), 127–132.Fekrat, F., Sahin, A., Yazici, K. M., & Aypar, U. (2006). Anaesthetists’ and surgeons’ estimation of preoperative anxiety by patients submitted for elective surgery in a university hospital. European Journal of Anaesthesiology, 23(3), 227–233.Leitch, J. A., Anderson, K., Gambhir, S., Millar, K., Robb, N. D., McHugh, S., & Kenny, G. N. C. (2004). A partially blinded randomised controlled trial of patient-maintained propofol sedation and operator controlled midazolam sedation in third molar extractions. Anaesthesia, 59(9), 853–860.Leitch, J. A., Sutcliffe, N., & Kenny, G. N. C. (2003). Patient-maintained sedation for oral surgery using a target-controlled infusion of propofol - a pilot study. British Dental Journal, 194(1), 43–45.Mackenzie, N. (1996). Sedation during regional anaesthesia: indications, advantages and methods. European Journal of Anaesthesiology (EJA), 13, 2–7.Mitchell, M. (2009). Patient anxiety and conscious surgery. The Journal of Perioperative Practice; Harrogate, 19(6), 168–173.Schnider, T. W., Minto, C. F., Gambus, P. L., Andresen, C., Goodale, D. B., Shafer, S. L., & Youngs, E. J. (1998). The Influence of Method of Administration and Covariates on the Pharmacokinetics of Propofol in Adult Volunteers. Anesthesiology: The Journal of the American Society of Anesthesiologists, 88(5), 1170–1182.Stonell, C. A., Leslie, K., & Absalom, A. R. (2006). Effect-site targeted patient-controlled sedation with propofol: comparison with anaesthetist administration for colonoscopy. Anaesthesia, 61(3), 240–247.Sury, M. R. J., Palmer, J. H. M. G., Cook, T. M., Pandit, J. J., & Mahajan, R. P. (2014). The State of UK anaesthesia: a survey of National Health Service activity in 2013. BJA: British Journal of Anaesthesia, 113(4), 575–584.Yun, M. J., Oh, A. Y., Kim, K. O., & Kim, Y. H. (2008). Patient-controlled sedation vs. anaesthetic nurse-controlled sedation for cataract surgery in elderly patients. International Journal of Clinical Practice, 62(5), 776–780.

Patient-maintained propofol sedation for orthopaedic surgery: patient variability in system use

http://irep.ntu.ac.uk/id/eprint/33980/1/11472_Breedon.pdf

Patient-maintained propofol sedation for orthopaedic surgery: patient variability in system use

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