Systemic arterial waveform analysis and assessment of blood flow during extracorporeal circulation.
BACKGROUND
The pressure recording analytical method (PRAM) is a method for real-time beat-to-beat quantification of peripheral blood flow based on the analysis of arterial waveform morphology. Since PRAM can be implemented in any conditions of flow, whether physiological or artificial, we assessed its accuracy in patients undergoing cardiac surgery during extracorporeal circulation (ECC), using the roller-pump device as the reference gold standard.


METHODS
We prospectively studied 32 patients undergoing elective coronary surgery. Flow values obtained by PRAM from the radial artery were compared with simultaneous values by thermodilution in physiological conditions of flow and with the roller-pump device readings during ECC.


RESULTS
Before and after ECC, the overall estimates of flow measured by PRAM closely agreed with thermodilution (mean difference 0.07 +/- 0.40 L/min). During ECC, PRAM estimates of flow also closely correlated with simultaneous pump readings (mean difference 0.11 +/- 0.33 L/min). At time of weaning from ECC, two patterns of hemodynamic adaptation were documented by PRAM following resumption of cardiac contraction: in most patients (n =26; 80%), cardiac output (CO) was stable (reduction < or = 10% compared to the steady ECC phase); six patients (20%) showed a fall in CO exceeding 10% and up to 38%.


CONCLUSIONS
PRAM provided accurate, continuous quantification of peripheral blood flow during each phase of cardiac surgery, including ECC, and allowed early recognition of patients with low CO during weaning from the pump.
Romano
Salvatore M
SM
Department of Critical Care and Surgery, University of Florence, Italy. m.romano@dac.unifi.it
Scolletta
Sabino
S
Olivotto
Iacopo
I
Biagioli
Bonizella
B
Gensini
Gian Franco
GF
Chiostri
Marco
M
Giomarelli
Pierpaolo
P
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001158:Arteries / Q000503:physiopathology*; D001794:Blood Pressure; D003327:Coronary Disease / Q000503:physiopathology / Q000601:surgery; D005112:Extracorporeal Circulation / Q000295:instrumentation* / Q000379:methods*; D005260:Female; D018056:Hemorheology / Q000295:instrumentation* / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods; D011446:Prospective Studies; D011673:Pulsatile Flow / Q000502:physiology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013815:Thermodilution; D013997:Time Factors