AAGBI/Anaesthesia Research Grant

PRotective Ventilation with Higher versus Lower PEEP
during General Anesthesia for Surgery in OBESE Patients - The PROBESE Randomized Controlled Trial (UK)

Prof Gary Mills

Complications occur after major surgery, producing a 4% death rate over 30 days. The most common serious complications involve the respiratory system. When patients undergo major surgery they in most cases need to be put on a ventilator to allow them to breathe. However ventilators blow air and oxygen into the lungs, rather than drawing it in, which is the way normal breathing works. When anaesthetised the muscles relax and the lungs start to close up under their own weight and the weight of the chest wall, heart and contents of the belly. The small air passages close up and the air is blown into the uppermost parts of the lung, which have less weight on them, but which then over-expand. Recent research appears to show that by blowing air into the lungs in relatively small breaths, there are fewer postoperative lung problems. However what pressures to use remains a major issue and postoperative lung damage and pneumonias remain a serious problem after major surgery. In between each breath, keeping some pressure in the breathing system is one way of trying to hold open the airways that would otherwise close up. This pressure is called positive end expiratory pressure or PEEP.

Obese people may need higher pressures to hold the airways open, because of the extra weight of the chest wall and belly, squashing the lungs. The aim of the study is to see if this is the case, and to see if fewer postoperative lung problems happen, or as may be the case, the higher pressure in the chest leads to problems with the blood returning to the heart and as a result lower blood pressure.

This is part of an international study and our role is to lead the study in the UK, we are therefore asking for money for a research nurse for one morning a week (0.1 whole time equivalent WTE) to help us locally, and help us deal with queries and other issues from the UK as a whole.

We will recruit towards a total of 748 patients from all countries. The aim will be to recruit 13-15 patients from each UK centre.

We will randomly decide that each patient should either receive a PEEP of 4 or 12 cmH2O. Those receiving the higher pressure will also receive something called lung recruitment. This is where large breaths are blown into the lung briefly to help re-expand the lungs. During the operation we will record all the pressures and volumes of each breath being blown into the lungs, as well as the blood pressure and anything that is needed to keep the blood pressure normal. Similarly after the operation we will record these and related parameters for 5 days after surgery and on the day of discharge and then the final outcome recorded on day 90 (by phone call).

The results of this study will help clarify a major issue as the population as a whole becomes older and fatter at all ages.

Development of a Personalised Care Plan Designed to Reduce Persistent Post-
Surgical Pain Following Breast Surgery

Dr John Williams and Dr Matthew Brown

The Problem

Lots of surveys have shown that following breast surgery, long-term pain (pain defined as lasting longer than 3 months after surgery) affects around half of patients. Given that 1 in 9 women will get breast cancer and that surgery is a cornerstone of treatment, persistent pain represents a major challenge in these patients. In addition to the suffering persistent pain causes to individual patients, we know that it places a substantial burden on families and carers, and that patients with persistent pain place a large demand on the NHS.

This research will see whether introducing a personalised care plan for patients having breast surgery reduces the amount of long term pain breast surgery patients get. it will assess the effect of the care plan on reducing the number of patients with pain at 3 and 12 months after their surgery.

The Personalised Care Plan

Much work has been performed identifying factors which place patients at increased risk of developing long-term pain following breast surgery. Lots of studies have also explored the influence of single treatments on stopping it from happening. However, to date, no attempts have been made to combine these evidence-based treatments in a treatment plan.

Therefore we have developed a personalised care plan known as a 'complex intervention' with help and feedback from both medical and nursing staff and patients and carers from out hospital. The care plan consists of a combination of small, evidence-based treatments which a patient gets before, during and after surgery. Treatments that feature in the care plan include trying to reduce any pain the patient may have before surgery, education on the causes of pain, treatment with a pain-killing medicine called pregabalin and the use of local anaesthetic to numb nerves near the breast during surgery. After surgery, patients on the care plan will receive regular pain reviews whilst an inpatient and will have access to a pain 'hot clinic' for rapid treatment of pain if long-term pain starts to develop.

How Will We Know if the Personalised Care Plan Works?

We will be able to tell if the personalised care plan works by comparing the amount of long-term pain experienced by patients who follow the care plan to that experienced by patients who follow 'usual care'. Usual care is the care that a patient would normally get at the time of their breast surgery.

Patients who agree to take part in our study are randomly allocated to either the personalised care plan or 'usual care'.

We will measure the number of different outcomes using questionnaires, these include; pain scores, quality of life scores and anxiety and depression levels. If we show that a personalised care plan reduces then we would use this approach for all patients undergoing breast surgery at our hospital.