Prediction of preload dependency using phenylephrine-induced peripheral perfusion index during general anaesthesia: a prospective observational study.

BACKGROUND: Tracking preload dependency non-invasively to maintain adequate tissue perfusion in the perioperative period can be challenging.The effect of phenylephrine on stroke volume is dependent upon preload. Changes in stroke volume induced by phenylephrine administration can be used to predict preload dependency. The change in the peripheral perfusion index derived from photoplethysmography signals reportedly corresponds with changes in stroke volume in situations such as body position changes in the operating room. Thus, the peripheral perfusion index can be used as a non-invasive potential alternative to stroke volume to predict preload dependency. Herein, we aimed to determine whether changes in perfusion index induced by the administration of phenylephrine could be used to predict preload dependency. METHODS: We conducted a prospective single-centre observational study. The haemodynamic parameters and perfusion index were recorded before and 1 and 2 min after administering 0.1 mg of phenylephrine during post-induction hypotension in patients scheduled to undergo surgery. Preload dependency was defined as a stroke volume variation of ≥ 12% before phenylephrine administration at a mean arterial pressure of < 65 mmHg. Patients were divided into four groups according to total peripheral resistance and preload dependency. RESULTS: Forty-two patients were included in this study. The stroke volume in patients with preload dependency (n = 23) increased after phenylephrine administration. However, phenylephrine administration did not impact the stroke volume in patients without preload dependency (n = 19). The perfusion index decreased regardless of preload dependency. The changes in the perfusion index after phenylephrine administration exhibited low accuracy for predicting preload dependency. Based on subgroup analysis, patients with high total peripheral resistance tended to exhibit increased stroke volume following phenylephrine administration, which was particularly prominent in patients with high total peripheral resistance and preload dependency. CONCLUSION: The findings of the current study revealed that changes in the perfusion index induced by administering 0.1 mg of phenylephrine could not predict preload dependency. This may be attributed to the different phenylephrine-induced stroke volume patterns observed in patients according to the degree of total peripheral resistance and preload dependency. TRIAL REGISTRATION: University Hospital Medical Information Network (UMIN000049994 on 9/01/2023).

Correlation between activated clotting time monitoring and heparin concentration measurement in a patient with antiphospholipid syndrome during cardiac valve surgery: a case report.

BACKGROUND: Anticoagulation management of patients with antiphospholipid syndrome (APS) undergoing cardiac surgery is challenging due to the prolongation of activated clotting time (ACT). Currently, no study has compared the utility of ACT monitoring using the Hemochron Jr. Signature+ and that of heparin concentration management using the Hemostasis Management System (HMS) Plus in patients with APS. CASE PRESENTATION: A 71-year-old woman with APS was scheduled to undergo an aortic valve replacement for aortic regurgitation. The ACT was measured using the Hemochron Jr. Signature+, and the heparin concentration was measured concurrently using the HMS Plus. ACT over 480 s corresponded to an adequate heparin concentration during cardiopulmonary bypass. The clinical course was uneventful, and no thrombotic or hemorrhagic complications were observed. CONCLUSION: In the present patient with APS, the Hemochron Jr. Signature+ was useful as an anticoagulation management during cardiac valve surgery.