Description

We all know that CPD is about keeping up to date, that this is expected of us and we should equally expect it of ourselves. However there are many areas of medicine where it is difficult to know what exactly up to date is. A good example of this is the usefulness of the Swan Ganz or Pulmonary Artery Floatation Catheter (PAFC). We regard the ability to insert a PAFC as one of the essential practical skills of any self respecting Anaesthetist, yet concerns have always existed over the usefulness of this in improving patient outcome. Despite this widely perceived doubt, many Anaesthetists and Intensivists, as well as many Cardiologists, Cardiac and Vascular surgeons, have remarkably polarised views on the usefulness of the Swan. Some believe in it’s absolute necessity to make correct clinical decisions in a wide range of situations, whilst others believe it to be a dangerous and needless invasive procedure that only acts as a distraction from the clinical picture and serves to only add additional risk. I am sure that we have all been told in our training that ‘no patient should ever die on ITU without a Swan in situ’, either in truth or in jest. At last some of these questions may be being answered. The excellent article by Sandham, et al. in Jan 2003, randomised nearly 2000 patients undergoing major elective and emergency surgery followed by ITU, into 2 groups, one with a PAFC and one without. Mortality was the same in each group. Interestingly there was a significant incidence of thromboembolic phenomena in the PAFC group. All studies are open to criticism, but this was a generally well conducted study and the results of such a significant study need to be absorbed by all. The next question is whether the PAFC makes a difference in the critically ill ITU population. This will hopefully be answered by the PACMAN study, reporting later this year.

It is unclear whether the lack of demonstrable difference in outcome so far shown from the PAFC studies reported so far is because manipulation of cardiovascular parameters makes no difference, or the complications resulting from such an invasive procedure as a PAFC offset any potential improvements from such manipulation. Such concerns have been a factor stimulating research into less invasive methods of cardiac output measurement. Many of these, using novel methods of measurement, have been commercially produced and are excellently reviewed in the postgraduate article in this issue by Kuper & Soni. These monitors of cardiac output also give estimation of cardiac filling pressures and useful information such as total lung water estimation. These represent significant advances in knowledge as well as in the clinical management of the critically ill. One assumes that these monitors will gain popularity from ease of use and lack of concerns over invasive complications. However when will they receive the same rigorous assessment of patient outcome as the PAFC? Most studies have so far concentrated on corroboration of findings with other forms of cardiac output monitor, usually the PAFC. This does not bypass the need for evidence as a base for our own practice. We hope we will not have to wait another 40 years before we can decide how to monitor our patients from evidence base, rather than personal experience.