Pain management in pigs undergoing experimental surgery; a literature review (2012– 4)  A.G. Bradbury, M. Eddleston, R.E. Clutton  British Journal of Anaesthesia  Volume 116, Issue 1, Pages 37-45 (January 2016) DOI: 10.1093/bja/aev301 Copyright © 2016 The Author(s) Terms and Conditions

Fig 1 Methodology for article selection. The integers indicate the article count at each level of selection. *The count discrepancy arises because of the number of articles describing use of drugs with different intra-, peri-, and postoperative effects. NMDA antagonist, N-methyl d-aspartate receptor antagonist; NSAID, non-steroidal anti-inflammatory drug. It was thought that papers describing pain or analgesia would therefore provide analgesic drugs; the dotted arrows indicate papers that did not follow this assumption. British Journal of Anaesthesia 2016 116, 37-45DOI: (10.1093/bja/aev301) Copyright © 2016 The Author(s) Terms and Conditions

Fig 2 Reported use of intraoperative analgesia. (a) The reported frequency of intraoperative analgesic drug use in 233 articles involving experimental surgery with recovery in pigs. Ketamine used alone was reportedly (63 articles) the most commonly used intraoperative analgesic. Thirty-eight articles described its use with xylazine (with or without other agents). Fentanyl was the most commonly used opioid agonist; its sole use being described in 11 articles. (b) The anaesthetics used for maintaining general anaesthesia in the selected articles. The articles represented in the column entitled ‘NMDA antagonists’ are also included in Fig. 2a. British Journal of Anaesthesia 2016 116, 37-45DOI: (10.1093/bja/aev301) Copyright © 2016 The Author(s) Terms and Conditions

Fig 3 Frequency of reporting of use of postoperative analgesic drugs in experimental surgery with recovery in pigs. Tramadol is categorized to reflect its multiple receptor interactions. The sum of all of these does not equal 87 because nine papers did not report the name of the analgesic given (see Fig. 4; seven articles gave no details, and two articles gave details other than the name of the drug). British Journal of Anaesthesia 2016 116, 37-45DOI: (10.1093/bja/aev301) Copyright © 2016 The Author(s) Terms and Conditions

Fig 4 Frequency of reported analgesic prescription details in studies reporting surgical recovery. Duration, duration of postoperative analgesic provision; Frequency, frequency of drug administration; Name, non-proprietary recommended international name; Route, route of drug administration. British Journal of Anaesthesia 2016 116, 37-45DOI: (10.1093/bja/aev301) Copyright © 2016 The Author(s) Terms and Conditions