Students can conduct research at The University of Auckland at an honours, masters
or PhD level.
We currently have a number of students working with us.
Information regarding studying at a postgraduate level at The University of Auckland
can be found on our Graduate Centre website.
Below is a list of students working in the department currently and abstracts from
theses of students who have recently completed their studies with us.
Current research students
- Ms Eva Winnebeck (PhD student, Department of Anaesthesiology) Supervisors: Dr Guy
Warman, Dept Anaesthesiology, Dr Craig Millar, School of Biological Sciences. Ms
Winnebeck is working on the Marsden funded 'Does Anaesthesia Steal Time?' project.
Her research focuses on the molecular and behavioural investigation of whether
general anaesthesia stops the circadian clock.
- Ms Amanda Potts (PhD student, Department of Anaesthesiology) Supervisors: Dr Guy
Warman, Dept Anaesthesiology, Assoc. Prof. Brian Anderson, Dept Anaesthesiology.
Ms Potts is working on a University of Auckland funded PhD project investigating
the Pharmacokinetics and Pharmacodynamics of the alpha 2 adrenoceptor agonist dexmedetomidine
and the influence this drug may have on sleep in patients in an ICU/ward setting.
- Ms Ashlee van der Heyden (Summer student, Department of Anaesthesiology) Supervisor:
Dr Guy Warman, Dept Anaesthesiology. Ms van der Heyden is working on a project investigating
the influence of general anaesthesia on memory and learning in honey bees.
- Ms Milica Milanovic (Summer student, Department of Anaesthesiology) Supervisors:
Dr James Cheeseman, Dr Guy Warman. Ms Milanovic is a medical student working on
a project designed to investigate the influence shift work has on performance and
drug error in anaesthetic registrars.
Below are abstracts from recently completed theses on chronobiology or chronobiology-related
topics at The University of Auckland.
James Cheeseman (PhD student 2003-2007)
Biological clocks pervade human physiology and behaviour. They control the daily
timing of sleep and dictate changes in body temperature, heart rate, the perception
of pain and variable responses to drugs. Anaesthetists have taken a conservative
approach to adopting the principles of chronobiology. Patients are often treated
rigidly as homeostatic organisms without regard to when drugs might have greater
effect or when toxicity might better be tolerated. Anaesthetists working rotating
shifts around the clock battle against the effects of circadian disruption and fatigue
which may lead to performance deterioration and an increase in the instance of drug
error. In this thesis the implications of circadian biology for anaesthesia are
examined both with respect to the patient and the anaesthetist.
Anaesthetists self-report
an overall sleep debt (45 min/night) which may contribute to drug error. Objective
measures of sleep and performance were measured using actigraphy, a validated psychomotor
vigilance task (PVT), and a novel drug recognition performance test (DRPT) developed
here. The quantity and quality of sleep was significantly worse (p = 0.019) on night
shifts (mean 5.51 h (SE 27 min)) vs. day shifts (mean 6.90 h (SE 26 min)). Sleep
deprivation was reflected in all measures of performance. DRPT performance was significantly
worse (p = 0.001) during night shifts (mean speed 8.07 (SE 0.23)) than during days
(mean speed 8.48 (SE 0.23). Anaesthetists made twice as many drug errors (n=12)
at the conclusion of night shifts than at any other time of the day. A clinical
trial was undertaken to examine the circadian variation in the action of the neuromuscular
blocker rocuronium. Patients remained paralysed for up to 15 to 20 minutes longer
in the morning than in the afternoon. The maximum duration (50 mins (SE 5 mins))
fell between 08:00 and 11:00 and the minimum duration (29 mins (SE 3 mins)) between
14:00 and 17:00 (p = 0.005).
A pilot study tested the effects of anaesthesia, surgery
and hospitalisation on the quality and quantity of sleep patients obtained. Sleep
patterns were measured for a week pre- and post-operatively and up to a week in hospital.
Increasing sleep disruption was associated with longer hospital stay and low light
exposure. In isolation,
the effects of circadian biology on the system of anaesthesia
are significant; when considered together, they have profound implications for
the conduct of anaesthesia, and for the well-being of patients and anaesthetists.
Anisoara Jardim (MSc student 2007-2008)
Sleep, controlled by the sleep homeostat and the circadian clock, is thought to
be essential for the reduction of fatigue, for learning and for memory consolidation.
In the hospital environment, sleep can be disrupted. The consequences of sleep disruption
due to hospitalisation, surgery and anaesthesia may include delayed post-operative
recovery. In this thesis, the presence and extent of sleep disruption and its relationship
to circadian disruption in the hospital setting were investigated. The implications
of low lighting for circadian disruption and post-operative recovery (as measured
by duration of hospital stay) are also considered. A pilot study was undertaken
to determine the presence and extent of sleep and circadian disruption in a small
subset of cardiac patients.
Using actigraphy to measure sleep/ wake cycles and core
body temperature as a circadian marker, patients were monitored pre-operatively,
post-operatively in-hospital and post-operatively at home. Three or more markers
of sleep disruption were recorded in all patients measured when comparing pre-operative
baseline levels with hospital levels. Circadian disruption, denoted by decreased
amplitude (p = 0.03), phase shifts (p = 0.07), and decreased coefficients of determination
(p = 0.002), was found. Patients were also found to have extremely decreased light
exposure in hospital, with a reduction of 83% in lighting from pre-operative levels
to hospitalisation, which may have contributed to their circadian disruption. In
order to investigate the lighting environment in the hospital setting, a comprehensive
assessment was done of the lighting levels in the Cardiothoracic ward and intensive
care unit at Auckland City Hospital. Lighting was found to be significantly brighter
in beds placed near the window compared to those placed furthest away, closer to
the wall (p<0.0001). An investigation of the potential effects of the darker lighting
environment found that patients in the window beds stayed on average 6.87 days,
while those in non-window beds stayed 7.67 days (p = 0.079). In women there was
a significant difference, with female patients in ICU window beds having a hospital
stay on average 6.86 days long while those in non-window beds stayed 8.67 days (p
= 0.037).
With evidence of sleep disruption and concurrent circadian disruption
in the pilot study and indications that lower light exposure is associated with
longer duration of hospital stay, the findings of this thesis present a possibility
for improving post-operative recovery through the introduction of lighting-based
interventions for the reduction of sleep and circadian disruption.
