Oxygen inhalation improves postoperative survival in ketamine-xylazine anaesthetised rats: An observational study

Autoři: Mare Mechelinck aff001;  Carolin Kupp aff001;  Johanne C. Krüger aff002;  Moriz A. Habigt aff001;  Marius J. Helmedag aff003;  René H. Tolba aff002;  Rolf Rossaint aff001;  Marc Hein aff001
Působiště autorů: Department of Anaesthesiology, Uniklinik RWTH Aachen, Aachen, Germany aff001;  Institute for Laboratory Animal Science and Experimental Surgery, Uniklinik RWTH Aachen, Aachen, Germany aff002;  Department of General, Visceral and Transplantation Surgery, Uniklinik RWTH Aachen, Aachen, Germany aff003
Vyšlo v časopise: PLoS ONE 14(12)
Kategorie: Research Article
doi: 10.1371/journal.pone.0226430



A simple but reliable and safe anaesthetic procedure is required for surgical interventions in small rodents. Combined ketamine and xylazine injections are often used in rats for less invasive surgery, possibly with spontaneous breathing and without airway management. However, there are important pitfalls to be avoided by special precautions and monitoring, as shown subsequently.

Study design

Observational study.


Twenty-four anaesthetic procedures for bile duct ligation, sham operation or carotid artery dilatation in 20 male Sprague-Dawley rats, preoperatively weighing between 440 and 550 g.


Intolerable high mortality rates occurred in the first 7 postoperative days while establishing a new experimental model in rats using ketamine-xylazine anaesthesia. Rats were spontaneously breathing ambient air during the first 12 surgeries without airway management. An observed high mortality rate in these animals led to a change in the trial protocol: the insufflation of 2 litres of oxygen per minute via nose cone during the following 12 rat surgeries. Retrospective comparison of the outcome (without oxygen vs. with oxygen insufflation) was conducted.


The perioperative mortality rate could be significantly reduced from 58% (7/12) to 17% (2/12) (p = 0.036) by oxygen insufflation via nose cone. Significantly different levels of intraoperative oxygen saturation (SpO2; 89 ± 4% [without oxygen] vs. 97 ± 0.5% [with oxygen], p < 0.0001), but no significant differences in heart rate (HR; 267 ± 7 beats minute–1 [bpm] [without oxygen] vs. 266 ± 6 bpm [with oxygen], p = 0.955) were observed.

Conclusions and clinical relevance

In summary, rats under ketamine-xylazine anaesthesia are susceptible to hypoxia. This may lead to increased delayed mortality related to hypoxia induced lung failure. Apparently, this is an underestimated problem. We highly recommend using additional oxygen insufflation in spontaneously breathing rats under ketamine-xylazine anaesthesia with basic monitoring such as measurement of oxygen saturation.

Klíčová slova:

Anesthesia – Breathing – Death rates – Medical hypoxia – Oxygen – Surgical and invasive medical procedures – Vascular surgery – Bile ducts


1. Smith I. Inhalation versus intravenous anaesthesia for day surgery. Ambulatory Surgery. 2003;10(2):89–94.

2. Karwacki Z, Kowianski P, Morys J. General anaesthesia in rats undergoing experiments on the central nervous system. Folia Morphol (Warsz). 2001;60(4):235–42.

3. Kersten JR, Schmeling TJ, Pagel PS, Gross GJ, Warltier DC. Isoflurane mimics ischemic preconditioning via activation of K(ATP) channels: reduction of myocardial infarct size with an acute memory phase. Anesthesiology. 1997;87(2):361–70. doi: 10.1097/00000542-199708000-00024 9286901

4. Kiani A, Mirmohammad Sadeghi M, Gharipour M, Farahmand N, Hoveida L. Preconditioning by isoflurane as a volatile anesthetic in elective coronary artery bypass surgery. ARYA Atheroscler. 2013;9(3):192–7. 23766776

5. Lotz C, Kehl F. Volatile anesthetic-induced cardiac protection: molecular mechanisms, clinical aspects, and interactions with nonvolatile agents. J Cardiothorac Vasc Anesth. 2015;29(3):749–60. doi: 10.1053/j.jvca.2014.11.012 25802192

6. Muchova L, Vanova K, Zelenka J, Lenicek M, Petr T, Vejrazka M, et al. Bile acids decrease intracellular bilirubin levels in the cholestatic liver: implications for bile acid-mediated oxidative stress. J Cell Mol Med. 2011;15(5):1156–65. doi: 10.1111/j.1582-4934.2010.01098.x 20518850

7. Dittmar MS, Fehm NP, Vatankhah B, Horn M. Ketamine/xylazine anesthesia for radiologic imaging of neurologically impaired rats: dose response, respiratory depression, and management of complications. Comp Med. 2004;54(6):652–5. 15679263

8. Krause A, Nowak Z, Srbu R, Bell HJ. Respiratory autoresuscitation following severe acute hypoxemia in anesthetized adult rats. Respir Physiol Neurobiol. 2016;232:43–53. doi: 10.1016/j.resp.2016.06.006 27378495

9. Green CJ, Knight J, Precious S, Simpkin S. Ketamine Alone and Combined with Diazepam or Xylazine in Laboratory-Animals—a 10 Year Experience. Lab Anim. 1981;15(2):163–70. doi: 10.1258/002367781780959107 7278122

10. Sumitra M, Manikandan P, Rao KV, Nayeem M, Manohar BM, Puvanakrishnan R. Cardiorespiratory effects of diazepam-ketamine, xylazine-ketamine and thiopentone anesthesia in male Wistar rats—a comparative analysis. Life Sci. 2004;75(15):1887–96. doi: 10.1016/j.lfs.2004.05.009 15302232

11. Amouzadeh HR, Sangiah S, Qualls CW Jr., Cowell RL, Mauromoustakos A. Xylazine-induced pulmonary edema in rats. Toxicol Appl Pharmacol. 1991;108(3):417–27. doi: 10.1016/0041-008x(91)90088-v 1902333

12. Amouzadeh HR, Qualls CW Jr., Wyckoff JH 3rd, Dzata GK, Sangiah S, Mauromoustakos A, et al. Biochemical and morphological alterations in xylazine-induced pulmonary edema. Toxicol Pathol. 1993;21(6):562–71. doi: 10.1177/019262339302100607 8052803

13. Giroux MC, Helie P, Burns P, Vachon P. Anesthetic and pathological changes following high doses of ketamine and xylazine in Sprague Dawley rats. Exp Anim. 2015;64(3):253–60. doi: 10.1538/expanim.14-0088 25818316

14. Picollo C, Serra AJ, Levy RF, Antonio EL, dos Santos L, Tucci PJF. Hemodynamic and thermoregulatory effects of xylazine-ketamine mixture persist even after the anesthetic stage in rats. Arq Bras Med Vet Zoo. 2012;64(4):860–4.

15. Ford NL, McCaig L, Jeklin A, Lewis JF, Veldhuizen RA, Holdsworth DW, et al. A respiratory-gated micro-CT comparison of respiratory patterns in free-breathing and mechanically ventilated rats. Physiol Rep. 2017;5(2).

16. Wellington D, Mikaelian I, Singer L. Comparison of ketamine-xylazine and ketamine-dexmedetomidine anesthesia and intraperitoneal tolerance in rats. J Am Assoc Lab Anim Sci. 2013;52(4):481–7. 23849447

17. Kwekel JC, Desai VG, Moland CL, Branham WS, Fuscoe JC. Age and sex dependent changes in liver gene expression during the life cycle of the rat. BMC Genomics. 2010;11:675. doi: 10.1186/1471-2164-11-675 21118493

18. Aller M-A, Arias J-L, Prieto I, Arias J. A suitable microsurgical method for obstructive cholestasis in the rat. Protocol Exchange. 2010.

19. Bendeck MP, Zempo N, Clowes AW, Galardy RE, Reidy MA. Smooth muscle cell migration and matrix metalloproteinase expression after arterial injury in the rat. Circ Res. 1994;75(3):539–45. doi: 10.1161/01.res.75.3.539 8062427

20. Roehl AB, Teubner A, Funcke S, Goetzenich A, Rossaint R, Tolba R, et al. Accidental renal injury by an external heating device during surgery in rats. Lab Anim. 2011;45(1):45–9. doi: 10.1258/la.2010.010076 21183530

21. Recommendations on anaesthesia methodologies for animal experimentation in rodents and rabbits [Internet]. 2016 [cited 06/05/2019]. http://www.gv-solas.de/fileadmin/user_upload/pdf_stellungnahme/Statement_on_anaesthesia_methodologies_2016.pdf.

22. Louis SF, Zahradka P. Vascular smooth muscle cell motility: From migration to invasion. Exp Clin Cardiol. 2010;15(4):e75–85. 21264073

23. Kim JM, Hong JH, Kim NJ, Cha EJ, Lee T-S. Two Algorithms for Detecting Respiratory Rate from ECG Signal. In: Magjarevic R, Nagel JH, editors. World Congress on Medical Physics and Biomedical Engineering 2006. Berlin, Heidelberg: Springer Berlin Heidelberg; 2007. p. 4069–71.

24. Roughan JV, Ojeda OB, Flecknell PA. The influence of pre-anaesthetic administration of buprenorphine on the anaesthetic effects of ketamine/medetomidine and pentobarbitone in rats and the consequences of repeated anaesthesia. Lab Anim. 1999;33(3):234–42. doi: 10.1258/002367799780578183 10780842

25. Rassler B, Marx G, Reissig C, Rohling MA, Tannapfel A, Wenger RH, et al. Time course of hypoxia-induced lung injury in rats. Respir Physiol Neurobiol. 2007;159(1):45–54. doi: 10.1016/j.resp.2007.05.008 17597012

26. Ganguly S, Panetta JC, Roberts JK, Schuetz EG. Ketamine Pharmacokinetics and Pharmacodynamics Are Altered by P-Glycoprotein and Breast Cancer Resistance Protein Efflux Transporters in Mice. Drug Metab Dispos. 2018;46(7):1014–22. doi: 10.1124/dmd.117.078360 29674491

27. Soltesz I, Deschenes M. Low- and high-frequency membrane potential oscillations during theta activity in CA1 and CA3 pyramidal neurons of the rat hippocampus under ketamine-xylazine anesthesia. J Neurophysiol. 1993;70(1):97–116. doi: 10.1152/jn.1993.70.1.97 8395591

28. Saha JK, Xia J, Grondin JM, Engle SK, Jakubowski JA. Acute hyperglycemia induced by ketamine/xylazine anesthesia in rats: mechanisms and implications for preclinical models. Exp Biol Med (Maywood). 2005;230(10):777–84.

29. Albrecht M, Henke J, Tacke S, Markert M, Guth B. Effects of isoflurane, ketamine-xylazine and a combination of medetomidine, midazolam and fentanyl on physiological variables continuously measured by telemetry in Wistar rats. BMC Vet Res. 2014;10:198. doi: 10.1186/s12917-014-0198-3 25149627

30. Curtis FG, Vianna PT, Viero RM, Fiorio PM, Silva LM, Braz JR, et al. Dexmedetomidine and S(+)-ketamine in ischemia and reperfusion injury in the rat kidney. Acta Cir Bras. 2011;26(3):202–6. doi: 10.1590/s0102-86502011000300008 21537522

31. Lee C, Jones TA. Effects of Ketamine Compared with Urethane Anesthesia on Vestibular Sensory Evoked Potentials and Systemic Physiology in Mice. J Am Assoc Lab Anim Sci. 2018;57(3):268–77. doi: 10.30802/AALAS-JAALAS-17-000131 29784077

32. Jimenez-Ruiz F, Khurram OU, Zhan WZ, Gransee HM, Sieck GC, Mantilla CB. Diaphragm muscle activity across respiratory motor behaviors in awake and lightly anesthetized rats. J Appl Physiol (1985). 2018;124(4):915–22.

33. Dodelet-Devillers A, Zullian C, Beaudry F, Gourdon J, Chevrette J, Helie P, et al. Physiological and pharmacokinetic effects of multilevel caging on Sprague Dawley rats under ketamine-xylazine anesthesia. Exp Anim. 2016;65(4):383–92. doi: 10.1538/expanim.16-0026 27263962

Článek vyšel v časopise


2019 Číslo 12