Do changes in perfusion index reflect changes in stroke volume during preload-modifying manoeuvres?

• Published in: Journal of clinical monitoring and computing Vol. 34; no. 6; pp. 1193 - 1198
• Main Authors: de Courson, Hugues, Michard, Frédéric, Chavignier, Camille, Verchère, Eric, Nouette-Gaulain, Karine, Biais, Matthieu
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.12.2020; Springer Verlag
• Subjects: Anesthesiology; Cardiology and cardiovascular system; Critical Care Medicine; Health Sciences; Human health and pathology; Intensive; Life Sciences; Medicine; Medicine & Public Health; Original Research; Statistics for Life Sciences; Lung recruitment manoeuvre; Pulse oximeter; Cardiac output; Perfusion index; Fluid responsiveness
• ISSN: 1387-1307; 1573-2614
• DOI: 10.1007/s10877-019-00445-2

Changes in stroke volume (deltaSV) induced by a lung recruitment manoeuvre (LRM) have been shown to accurately predict fluid responsiveness during protective mechanical ventilation. Cardiac output monitors are used in a limited number of surgical patients. In contrast, all patients are monitored with a pulse oximeter, that may enable the continuous monitoring of a peripheral perfusion index (PI). We postulated that changes in PI (deltaPI) may reflect deltaSV during brief modifications of cardiac preload. We studied 47 patients undergoing neurosurgery and ventilated with a tidal volume of 6–8 ml/kg. All patients were monitored with a pulse contour system enabling the continuous monitoring of SV and with a pulse oximeter enabling the continuous monitoring of PI. LRMs were performed by increasing airway pressure up to 30 cmH 2 0 for 30 s. Fluid loads (250 ml of saline 0.9% in 10 min) were performed only in patients who experienced a deltaSV > 30% during LRMs (potential fluid responders). LRMs induced a 26% decrease in SV (p < 0.05) and a 27% decrease in PI (p < 0.05). We observed a fair relationship between deltaPI and deltaSV (r 2  = 0.34). A deltaPI ≥ 26% predicted a deltaSV > 30% with a sensitivity of 83% and a specificity of 78%  (AUC  =  0.84, 95%CI 0.71–0.93). 24 patients experienced a deltaSV > 30% and subsequently received fluid. Fluid loads induced a 16% increase in SV and a 17% increase in PI, but fluid-induced deltaPI and deltaSV were weakly correlated (r 2  = 0.19). In neurosurgical patients, we conclude that deltaPI may be used as a surrogate for deltaSV during LRMs but not during fluid loading.