AP-HP, Service de médecine intensive-réanimation, Hôpital de Bicêtre, DMU 4 CORREVE, Inserm UMR S_999, FHU SEPSIS, CARMAS, Université Paris-Saclay, 78 rue du Général Leclerc, 94270, Le Kremlin-Bicêtre, France.
Department of Anesthesia and Intensive Care B, Department of Surgery, Dentistry, Gynaecology and Pediatrics, University of Verona, AOUI-University Hospital Integrated Trust of Verona, Verona, Italy.
Crit Care. 2024 Sep 16;28(1):305. doi: 10.1186/s13054-024-05085-w.
To detect preload responsiveness in patients ventilated with a tidal volume (Vt) at 6 mL/kg of predicted body weight (PBW), the Vt-challenge consists in increasing Vt from 6 to 8 mL/kg PBW and measuring the increase in pulse pressure variation (PPV). However, this requires an arterial catheter. The perfusion index (PI), which reflects the amplitude of the photoplethysmographic signal, may reflect stroke volume and its respiratory variation (pleth variability index, PVI) may estimate PPV. We assessed whether Vt-challenge-induced changes in PI or PVI could be as reliable as changes in PPV for detecting preload responsiveness defined by a PLR-induced increase in cardiac index (CI) ≥ 10%.
In critically ill patients ventilated with Vt = 6 mL/kg PBW and no spontaneous breathing, haemodynamic (PICCO system) and photoplethysmographic (Masimo-SET technique, sensor placed on the finger or the forehead) data were recorded during a Vt-challenge and a PLR test.
Among 63 screened patients, 21 (33%) were excluded because of an unstable PI signal and/or atrial fibrillation and 42 were included. During the Vt-challenge in the 16 preload responders, CI decreased by 4.8 ± 2.8% (percent change), PPV increased by 4.4 ± 1.9% (absolute change), PI decreased by 14.5 ± 10.7% (percent change), PVI increased by 1.9 ± 2.6% (absolute change), PI decreased by 18.7 ± 10.9 (percent change) and PVI increased by 1.0 ± 2.5 (absolute change). All these changes were larger than in preload non-responders. The area under the ROC curve (AUROC) for detecting preload responsiveness was 0.97 ± 0.02 for the Vt-challenge-induced changes in CI (percent change), 0.95 ± 0.04 for the Vt-challenge-induced changes in PPV (absolute change), 0.98 ± 0.02 for Vt-challenge-induced changes in PI (percent change) and 0.85 ± 0.05 for Vt-challenge-induced changes in PI (percent change) (p = 0.04 vs. PI). The AUROC for the Vt-challenge-induced changes in PVI and PVI was significantly larger than 0.50, but smaller than the AUROC for the Vt-challenge-induced changes in PPV.
In patients under mechanical ventilation with no spontaneous breathing and/or atrial fibrillation, changes in PI detected during Vt-challenge reliably detected preload responsiveness. The reliability was better when PI was measured on the forehead than on the fingertip. Changes in PVI during the Vt-challenge also detected preload responsiveness, but with lower accuracy.
为了检测以 6 毫升/公斤预测体重（PBW）潮气量（Vt）通气的患者的前负荷反应性，Vt 挑战包括将 Vt 从 6 增加到 8 毫升/公斤 PBW，并测量脉搏压变化（PPV）的增加。然而，这需要动脉导管。灌注指数（PI）反映了光容积描记信号的幅度，可能反映了每搏量，其呼吸变化（脉搏变异指数，PVI）可能估计 PPV。我们评估了 Vt 挑战诱导的 PI 或 PVI 变化是否与 PPV 变化一样可靠，以检测由 PLR 诱导的心脏指数（CI）增加≥10%定义的前负荷反应性。
在以 6 毫升/公斤 PBW 潮气量通气且无自主呼吸的危重症患者中，在 Vt 挑战和 PLR 试验期间记录血流动力学（PICCO 系统）和光容积描记（Masimo-SET 技术，传感器放置在手指或前额）数据。
在 63 名筛选出的患者中，由于 PI 信号不稳定和/或心房颤动，有 21 名（33%）被排除，42 名被纳入。在 16 名前负荷反应者的 Vt 挑战中，CI 降低了 4.8±2.8%（百分比变化），PPV 增加了 4.4±1.9%（绝对变化），PI 降低了 14.5±10.7%（百分比变化），PVI 增加了 1.9±2.6%（绝对变化），PI 降低了 18.7±10.9%（百分比变化），PVI 增加了 1.0±2.5%（绝对变化）。所有这些变化都大于无前负荷反应者。检测前负荷反应性的 ROC 曲线下面积（AUROC）为 Vt 挑战诱导的 CI（百分比变化）的 0.97±0.02，Vt 挑战诱导的 PPV（绝对变化）的 0.95±0.04，Vt 挑战诱导的 PI（百分比变化）的 0.98±0.02，以及 Vt 挑战诱导的 PI（百分比变化）的 0.85±0.05（p=0.04 与 PI 相比）。Vt 挑战诱导的 PVI 和 PVI 的 AUROC 明显大于 0.50，但小于 Vt 挑战诱导的 PPV 的 AUROC。
在无自主呼吸和/或心房颤动的机械通气患者中，Vt 挑战期间检测到的 PI 变化可靠地检测到前负荷反应性。PI 在前额测量时比在指尖测量时更可靠。Vt 挑战期间 PVI 的变化也可检测前负荷反应性，但准确性较低。
