AAGBI/Anaesthesia Research Grant

Comprehensive mouth-care to reduce Post-operative Pneumonia (CUPPA)

Dr Tom Clark, Dr Charles Gibson, Dr Gary Minto

Background
Pneumonias (chest infections) are one of the most common serious complications after major surgery. They increase risk of death, length of hospital stay and delay recovery. Some explanations for why patients are at risk of pneumonia after major abdominal surgery include poor cough, poor deep breathing and poor mobility; all often due to the surgical wound and pain. However, another important cause may be the passage of bacteria from the stomach and throat into the lungs both during general anaesthesia and over the early days of recovery after surgery.

We routinely treat patients who are sedated and ventilated on the Intensive Care Unit (ICU) with anti-septic mouthwashes (e.g. chlorhexidine) to prevent the development of pneumonia. However, this is not a treatment that we use in patients who are recovering from major abdominal surgery and who have not been admitted to ICU. This is because there is almost no research into this area, despite our estimate that pneumonias happen in at least 8% of 'at risk' patients having major abdominal surgery.

Aims
To pilot a multi-centred trial to test a comprehensive oral hygiene regimen in patients undergoing major abdominal surgery.

Methodology
This study will be conducted by the South West Anaesthesia Research Matrix and will recruit patients from the 6 trusts within our network.
We plan to recruit 120 patients booked for elective major abdominal surgery and who are predicted to be at moderate or high risk of developing a post-­-operative chest infection.

Patients will be randomised to one of two groups:-

  • A comprehensive oral hygiene regimen:
    • Teeth brushing with chlorhexdine dental gel immediately prior to general anaesthesia
    • Mouthwash with chlorhexidine immediately prior to general anaesthesia
    • Daily teeth brushing with chlorhexidine dental gel for up to 7 days after surgery
    • Twice daily mouthwash with chlorhexidine for up to 7 days after surgery.
      Temporary plaque staining tablets will be used to prove plaque removal by this regimen.
  • "Normal" care.

Primary outcomes: Patient compliance with our treatment regime and the ability of
SWARM to recruit to this trial. Secondary outcomes: Chest infection rates.

Patient consent and recruitment: All patients undergoing elective major abdominal surgery will be seen in pre­-operative assessment clinics where they will be reviewed by clinical staff. Members of this clinical team will approach appropriate patients to give details of the study. The research team will approach patients on day of surgery to confirm consent and recruit to the trial.

Expected Outcomes
This is a pilot study to test the comprehensive oral hygiene regime, test our research network model and to undertake a sample­-size calculation. In a larger study we would test the prophylactic use of comprehensive oral hygiene regime to reduce the rate of post-­-operative chest infections.

Implications
Treatment with a comprehensive oral hygiene regime could be a simple, cheap, effective method to reduce post­-operative chest infections. Due to the sheer number of operations per year, its use could have a large impact on patient recovery
after surgery and patient outcome.


Surgicric 2: A comparative bench study with two established emergency cricothyrotomy techniques in a porcine model

Dr Louisa Chrisman

Background
Can't intubate, can't ventilate (CICV) is a life threatening situation arising from failure to provide oxygen to an anaesthetised patient, which can result in catastrophic brain injury or death. Fortunately, few anaesthetists expect to experience this scenario more than once in their careers (1:50,000 general anaesthetics). Despite this, it is imperative that we are optimally prepared for such an eventuality. The appropriate emergency equipment must be available to permit life-saving cricothyroidotomy (a procedure whereby a hole is made in the neck, through which the patient can breathe). Various devices have been developed to carry out cricothyroidotomy over the years, and these include narrow-bore needles, wire-guided techniques, and pre-assembled cannula-over-needle kits. A simple surgical technique is offered as an alternative within the Difficult Airway Society CICV guidelines but of all these, there is little consensus as to which is the quickest and safest.

Our group previously investigated the new Surgicric I device, with interesting findings (to be submitted for publication). Following discussions with VBM, they have now modified the device and launched Surgicric2. This looks to provide a simple pre-prepared 'all-you-need' surgical cricothyroidotomy kit which may bridge the divide between established needle cricothyroidotomy and surgical techniques. VBM envisage that the problems we encountered in our earlier study might be overcome, and we will now compare this with the Melker set which employs either a surgical technique or the seldinger technique of threading a cricothyrotomy tube over a wire. Although potentially time consuming, this technique is familiar to anaesthetists and was rated higher than the surgical technique in a recent study.

Aims
We plan to carry out a bench study, comparing 3 methods for securing emergency tracheal access on a porcine airway.

Methodology
We will perform a randomised cross-over study to investigate the Melker surgical cricothyroidotomy, Seldinger Cricothyrotomy, and VBM Surgicric2 techniques.

Having excluded the requirement for Research Ethics Approval (Appendix F), anaesthetists (n=25) will be recruited and consented. They will receive a standardised 5 minute demonstration of each technique, and permitted a single practise insertion into a manikin neck. They will then perform cricothyroidotomy on a fresh pig larynx with each method in randomised order. The pig larynx and windpipe have been used in previous studies, and found to provide a realistic anatomical representation of the human airway. It will be housed in an airway training manikin, and attached to a reservoir bag simulating the lungs.

Outcomes to be measured include success rate, duration of the insertion attempt (opening of pack to first successful 'ventilation'), tracheal damage, cannula location, participant ability, confidence, preference and ease of use.

Outcomes
We expect one technique to be the fastest to insert. It is possible that such a device is also the most user-friendly, and favoured by the participants.

Implications
Data acquired will inform anaesthetists on a national scale of the performance of the as yet untested Surgicric2 device. If superior to other devices, it could improve outcomes of CICV scenarios, and save lives.

Please see the NIAA's position statement on the use of animals in medical research.


Predicting perioperative risk in patients with Acute Coronary Syndromes

Dr Rob Sanders & Dr Alex Bottle

Background
When proposing a potential operation to a patient it is critical to define both the risks and the benefits of the procedure, leading to the concept of preoperative optimisation to reduce the risks for patients. Certain diseases, such as previous heart attacks, increase perioperative risk and hence it is important to define strategies that may reduce this risk. Consistent with a raised mortality for up to a year following a heart attack, we have recently shown that elective major joint surgery conducted within a year of a heart attack is associated with increased perioperative death (within 30 days of the operation) and have proposed that risk may be reduced by delaying surgery until after this threshold.

However this may impact significantly on a patient's quality of life (eg. pain from an arthritic joint or impaired mobility) and also their health (eg. reduced ability to exercise).

Methods
Therefore we propose to provide further data on this issue by looking more closely at a range of heart attack related factors (including the time interval between the heart attack and surgery, area of the heart injured and type of treatments of the heart attack) and perioperative risk. We will achieve this by anonymous linkage of two large healthcare databases, the Myocardial Infarction National Audit Project (MINAP) and Hospital Episode Statistics (HES). We will select a large cohort of non-cardiac surgical procedures from HES and identify the preoperative heart attack factors from MINAP. Other diseases will be identified from HES. Our outcome measures will be perioperative death, postoperative heart attack, prolonged length of stay in hospital and emergency readmission in 28 days of discharge.

Aims
Through this work we hope to define, using a larger cohort of non-cardiac surgical
cases, the perioperative risk associated with prior heart attacks, including the impact of time interval between the initial heart attack and subsequent operation. Our intention is to provide information for clinicians about when to safely schedule surgery following a heart attack and also identify potentially modifiable factors that can be tested in further studies as methods to reduce perioperative risk.