1. The use of pulmonary artery catheters and cardiac output monitoring devices on a busy combined cardiac and general intensive care unit
Dr U. Puar1, Dr A. Green2, Dr A. B. Ahmed3
1 Clinical Fellow, 2 Anaesthetic Registrar, 3 Consultant Anaesthetist
Glenfield Hospital, Leicester, UK.
 Introduction
 Discussion
PAC and CO monitoring device usage is highly selective at our unit and reflects patient illness severity. Routine insertion of introducer sheaths could be reduced. The technique of siting a single lumen cannula that can be rewired to pass an introducer sheath, in the event that a PAC is required, could be a more cost effective alternative.
The dawn of the flow-directed balloon-tipped catheter arrived in 1970[1], a culmination of 40 years of work into cardiac catheterization techniques[2]. With the development of the thermodilution method in determining cardiac output, the Pulmonary Artery Catheter (PAC) became a ubiquitous tool. A common misconception that it was a therapeutic as opposed to a diagnostic tool led to its overuse or misuse and consequently misplaced fears over increased mortality[2]. The use of PACs has seen a steady decline, with usage varying between institutions, ranging from routine insertion to only 5-10% of the patient population[3]. We wanted to quantify the usage of PACs at our institution and consequently whether routine intraoperative insertion of the PA catheter introducer sheath is necessary.
Fig 1
Fig 2
 Conclusion
We assert that there is still a place for PAC usage in the 21st century in goal directed therapy in appropriately selected populations.
 References
Swan HJ, Ganz W, et al. Catheterization of the heart in man with the use of a flow-directed balloon-tipped catheter. N Engl J Med. 1970; 283:447.
Chatterjee K. The Swan-Ganz catheters: past, present, and future. A viewpoint. Circulation. 2009; 119:
Ranucci M. Which cardiac surgical patients can benefit from placement of a pulmonary artery catheter? Critical Care 2006; 10(Suppl 3): S6
EUROSCORE Project Group, presented at EACTS, Lisbon, October 2011.
J. Kaur, G. Lau and J. Williams. Survey of the use of pulmonary artery sheaths in cardiac anaesthesia and intensive care. Department of Anaesthesia and Intensive care, University Hospitals of Leicester, Leicester, UK
Assessment of the clinical effectiveness of pulmonary artery catheters in management of patients in intensive care (PAC-Man): a randomised controlled trial. Lancet 2005; 366: 472–77
 Methods
Fig 5
Fig 3
Fig 4
The ICU and Cardiac Surgical admission and audit database was consulted retrospectively, covering a six-month period between November 2010 and April 2011.
Fig 1-5 refers to the patient group who required CO monitoring on ICU. Fig 1: ASA grade of surgical patients . Fig 2: Euroscore II[4]figures for cardiac surgical patients. Fig 3: Pre-op and post-op eGFR figures in patients who eventually require CO monitoring. Fig 4: LV function in cardiac surgical patients peri-op. Fig 5: Shows the number of inotropic infusions in patients before CO was instituted.
In total, 56 PACs were floated and 16 non-invasive cardiac output (NI-CO) devices used. In the cardiac surgical group, 43 patients had a PAC only, seven had a NI-CO only whilst the remaining seven had both.
Presented in figures 1-5 are the descriptors of the patients in the CO monitored group. The average Euroscore II was 8.75% (range %), pre-op mean eGFR=63.3ml/min (range 90-17), deteriorating post-op to a mean eGFR=19.5ml/min (range 90-10). Also, a significant proportion had moderate to poor LV function and required multiple inotropic support on ICU.
 Results
There were a total of 499 patients admitted to the ICU during the period in question, males=354 (70.9%), females=145 (29.1%). The majority, n=469 (94%) were cardiac surgical patients, whilst the remaining n=30 (6%) were general medical patients. Sixty-three patients, males=47 (75%), females=16 (25%), mean age of 67 years with a range of 36 to 84 years, had cardiac output and haemodynamic monitoring instituted in addition to standard parameters (i.e. blood pressure, heart rate and central venous pressure). Table 1 showing patients who had cardiac output (CO) monitoring:
Assuming 90%[5] of patients presenting for cardiac surgery have a PA sheath sited intraoperatively (n=422), then the rate of conversion of the PA sheath to floating a PAC, is 11.8%. Alternatively, only 10.7% (50/469) of all cardiac surgical patients at this unit had a PAC floated.
It is of interest to note that overall mortality in the non-CO monitored population was 4.36% (19/436) versus 7.94% (5/63) in the CO monitored group (4/5 had a PAC). Whilst hospital mortality has not been reduced through the use of PAC, there has been no clear evidence of harm[6]. However, further studies are needed to elucidate whether PAC could be of benefit when strict management protocols are adhered to.
The overall cost of this practice, contrasted to the alternative of placing single-lumen cannula for re-wiring when a PAC is required, is outlined below:
Current practice: 422 introducer sheaths and 50 PAC cost £14,776
Under proposed practice: 422 angiocathsTM and 50 introducer sets/PAC cost £7723
Potential saving: £7053
Post-op Cardiac
General
CABG
AVR
MVR
TVR
Surgical other
Medical other N= 24 21 11 1 3
Common reasons cited for CO monitoring, particularly when deciding to place a PAC, included guiding inotropic support, monitoring filling, haemodynamics and fluid therapy, clinically unstable patient and metabolic disturbance.
 Acknowledgements
Jelena Simcic, ITU Audit Management Clerk, Glenfield Hospital.