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).

[Two Cases of Large Gynecological Tumor Complicated by Preoperative Deep Vein Thromboembolism and Pulmonary Thromboembolism-Should We Use Inferior Vena Cava Filters ?-].

We experienced two cases of large gynecological tumor resection with co-existing deep vein thrombo- embolism (VTE) and pulmonary thromboembolism (PTE). Despite perioperative anticoagulation, one of the two patients developed dyspnea with massive PTE postoperatively, although the other patient did not have any postoperative complications. To prevent fatal mas- sive PTE, temporary inferior vena cava (IVC) filter might have been effective during perioperative period in these cases. Since there are wide variations among institutes regarding the perioperative application of temporary IVC filters for patients with co-existing VTE and/or PTE before surgery, guidelines or recom- mendations for appropriate usage of perioperative IVC filter are necessary.

Wide discrepancies in activated clotting times measured by two devices were detected for a patient with lupus anticoagulant in a cardiac surgery.

INTRODUCTION:: For a patient with lupus anticoagulant (LA), activated coagulation time (ACT) was measured with two different types of devices (HEMOCHRON® 801 and HEMOCHRON® Jr). CASE REPORT:: ACTs during heparinization measured with the HEMOCHRON® 801 were over the range of measurement, while those with the HEMOCHRON® Jr. reflected an almost normal response to heparin. DISCUSSION:: The phospholipid contained in an activating agent of the HEMOCHRON® Jr was suggested to have counteracted the effect of LA. CONCLUSION:: It was indicated that the coagulation status for LA-positive patients might be better assessed by ACT measured with phospholipid in an activating agent, although careful interpretation is required.