Anaesthesia Unit
Research Interests
- Complications occurring under anaesthesia particularly cardiovascular.
- Pain management in companion animals.
- Local anaesthesia techniques.
- Intravenous anaesthesia.
- Anaesthetic breathing systems.
Research currently underway
Risk factors for the development of hypotension in cats undergoing anaesthesia in a University Veterinary Hospital.
(A thesis submitted successfully for the degree of Master of Veterinary Public Health Management by John Alexander, Supervisor: Sanaa Zaki).
A retrospective study undertaken to investigate the incidence of hypotension during anaesthesia of cats and to explore factors which might have an effect on development of such a hypotensive episode. This was a case-control study using three consecutive years of data comprising the records of 766 cats accrued from anaesthesia records from the University Veterinary Teaching Hospital Sydney.
A comparison of propofol, thiopentone and a combination propofol/thiopentone to induce anaesthesia in the dog.
(BVSc Honours student: Racheal Bailey 2010, Supervisors: Sanaa Zaki & Kim Ticehurst)
The aim of this study is to compare three techniques used to induce unconsciousness in dogs undergoing general anaesthesia – propofol alone, thiopentone alone, and thiopentone and propofol in combination – in a clinical setting by using a controlled, randomised, prospective clinical trial. In order to compare the drugs the study will determine the amount of thiopentone required to induce unconsciousness when used in combination with 1mg/kg propofol; compare the quality of induction and recovery between the protocols; and compare the cardiovascular and respiratory effects of the 3 protocols.
Rebreathing and the Humphrey ADE System
(BVSc Honours student: Elizabeth Gale 2010, Supervisors: Sanaa Zaki & Kim Ticehurst)
The Humphrey ADE System is used to deliver oxygen and anaesthetic agents to both humans and animals during general anaesthesia. The main attraction of the Humphrey ADE System is that it is said to require significantly lower fresh gas flow rates (ie less mLs of anaesthetic agent and oxygen are introduced into the system per kg/min) than other commercially available breathing systems. The Humphrey ADE System is said to be safely used at only 100ml/kg/min. Hence, veterinary practitioners can save on the cost of anaesthetic agents and oxygen when using this system.
The aim of this study is to investigate whether these lower fresh gas flow rates are indeed safe, by evaluating respiratory pattern, end tidal CO2 levels and blood gas analysis in cats and small dogs under anaesthesia.
Understanding the Pain of Osteoarthritis of the knee joint
(PhD candidature: Sanaa Zaki, Supervisors: Dr Mark Connor & Dr Chris Little)
This research enquiry utilizes two established models of OA in mice to study changes in the properties of sensory neurons innervating the mouse knee joint and the associated development of nociceptive hypersensitivity. The first is a non-inflammatory surgical model and the second is an inflammatory antigen induced arthritis model.
By characterizing the nerves of the knee joint that transmit pain signals and identifying how the nerve signaling changes in a knee joint with acute or chronic arthritis, more effective strategies can be developed to treat the pain of osteoarthritis.
The key outcomes of this study are:
- To count and characterize the nerve cells that innervate the knee joint of the mouse using retrograde tracing techniques.
- To identify any changes in nerve cell number or characteristics in mice with acute or chronic OA, using immunohistochemistry techniques.
- To identify changes in gene expression in the dorsal root ganglia that innervate the knee joint in mice with acute or chronic OA using real time PCR.
- To relate any identified changes in the innervation of the knee joint to the pain and reduced limb function that mice with acute or chronic OA display using locomotive function tests and established pain assessment methods.
The use of an inflammatory model of arthritis (AIA) will enable investigation of the role that inflammation plays in the pain mechanisms of arthritis and therefore validate that the findings we make with the surgically induced model of arthritis are specific to the “non-inflammatory” degenerative joint disease process (osteoarthritis).