in 1988 shoemaker and colleagues   published a pivotal and rather complex paper that demonstrated for the first time that increasing cardiac output and oxygen delivery peri - operatively in high risk surgical patients led to a dramatic fall in morbidity and mortality . his group had previously shown that using simple clinical criteria , patients at high risk of dying in the post - operative period could be easily identified . he estimated that as many as 8% to 10% of patients undergoing major surgery in the usa were in this high risk group , with a hospital mortality well in excess of 20% since these papers were published , numerous studies have by and large confirmed these original findings . boyd and colleagues   and woods and colleagues   found that increasing cardiac output and oxygen delivery pre - operatively to target values of 4.5 l / min / mand 600 ml / min / m , respectively , which were maintained into the post - operative period , all led to a dramatic reduction in both mortality and morbidity . these studies all used the pulmonary artery catheter for monitoring cardiac output and a combination of intra - venous fluids and inotropes to achieve the hemodynamic targets . other workers [ 4 - 6 ] have used oesophageal doppler to measure cardiac output intra - operatively and achieved maximal stroke volume using frequent fluid challenges but with inotropes . such protocols have consistently led to significant reductions in post - operative complications and hence hospital length of stay . two further studies   demonstrated that when such protocols were used solely in the immediate postoperative period , similar benefits were still obtained . it should be stressed that these protocols have been used in a wide variety of patients , ranging from those undergoing major abdominal and vascular surgery to repair of fractured neck or femur or major cardiac surgery . disappointingly , despite this body of evidence and meta - analyses that clearly show the overall benefit of this approach , the technique has not been widely adopted for reasons that are not entirely clear . these probably include disbelief , ignorance and logistical difficulties , particularly in regard to intensive care facilities . in addition , the major debate about the efficacy of the pulmonary artery catheter has further compounded the difficulties . the relative lack of intensive care beds in the uk has in general made it impossible to admit high risk surgical patients to the intensive care unit pre - operatively . it has been estimated that in the uk approximately 40,000 surgical patients are admitted annually for post - operative intensive care , with an overall hospital mortality of around 20% . this is associated with a prolonged length of stay and a very high complication rate . it was against this background that the recently published study by pearse and colleagues   was undertaken . would it be feasible to develop a protocol in which identical goals to those achieved by shoemaker almost 20 years ago for cardiac index and oxygen delivery would be sought purely in the immediate post - operative period ? and could these hemo - dynamic goals be reached and maintained using the relatively new technology of pulse contour analysis calibrated by lithium dilution ? and , furthermore , if such a protocol did lead to a significant improvement in outcome , could it then be implemented on a routine clinical basis in all patients receiving post - operative care in the intensive care unit at st george 's hospital in london ? the study did of course show a dramatic reduction of 12 days in the mean length of stay , mainly due to a fall in the post - operative infection rate . furthermore , about two thirds of the study was carried out by senior nursing staff , giving encouragement to the notion that a routine clinical protocol that could be run by the general intensive care nurses might indeed be developed . the protocol now in use is largely based on that used in the study and is run by the nurse assigned to the care of the patient . immediately on return from the operating theatre , the patient is connected to the lidco monitor via the radial arterial line and the lithium calibration procedure completed via the central venous line . oxygen delivery is continuously monitored and increased towards the target value of 600 ml / min / m , initially with intravenous colloid and then with the addition of dopexamine at a dose no higher than 1 g / kg / min . the target value is not reached in a minority of patients , usually because the heart rate increases above 100 beats per minute . it is hoped that about 500 patients annually will be treated with this protocol and , based on the results obtained in the study , up to 20 lives will be saved . to the delight of the hospital managers it is estimated that because of the projected reduction in hospital stay there should be an annual cost saving of at least  2,000,000 . it is encouraging to note that at the time of writing the pearse and colleagues ' study   is third in the annual list of most articles published in critical care   despite being on this list for only three months . this does suggest that the intensive care community is showing real interest , which hopefully will be translated into routine clinical practice .
despite studies clearly demonstrating significant benefit from increasing oxygen delivery in the peri - operative period in high risk surgical patients , the technique has not been widely accepted . 
 this is due to a variety of reasons , including non - availability of beds , particularly in the pre - operative period , and the requirement of inserting a pulmonary artery catheter . 
 there are now data that suggest that increasing oxygen delivery post - operatively using a nurse - led protocol based on pulse contour analysis leads to a major improvement in outcome with reduction in infection rate and length of hospital stay .