Hemodynamic variations in arterial wave reflection associated with the application of increasing levels of PEEP in healthy subjects.

Positive end-expiratory pressure (PEEP) may affect arterial wave propagation and reflection, thus influencing ventricular loading conditions. The aim of the study was to investigate the hemodynamic variations in arterial wave reflection (i.e., wave reflection time, augmentation index, left ventricular ejection time, diastolic time, SEVR) associated with the application of increasing levels of PEEP in healthy subjects. We conducted a prospective observational study. Study population was selected from students and staff. Pulse contour wave analysis was performed from the right carotid artery during stepwise increase in PEEP levels (from 0 cmH2O, 5 cmH20, 10 cmH2O) with applanation tonometry. Sixty-two healthy volunteers were recruited. There were no significant changes in heart rate, augmentation index (AIx), left ventricular ejection time, Diastolic time (DT) among all of the different steps. A significant increase of time to the inflection point (Ti) was observed during all steps of the study. Diastolic area under the curve (AUC) divided by systolic-AUC (SEVR) increased from baseline to PEEP = 5 cmH2O, and from baseline to PEEP = 10 cmH2O. AIx and Ti were significantly correlated (directly) at the baseline and during PEEP = 10 cmH2O. Ti and DT were significantly correlated at the baseline and during PEEP = 5 cmH2O. In our preliminary results, low levels of PEEP played a role in the interaction between the heart and the vascular system, apparently mediated by a prolongation of the diastolic phase and a reduction in the systolic work of the heart.Clinical trials registration number: NCT03294928, 19/09/2017.

Clinical and predictive value of blood lactate levels during cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC): a comparative analysis.

Postoperative outcome after cytoreductive surgery followed by hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) is strongly related to surgical and anesthesiologic expertise. This study aims to evaluate the clinical significance and prognostic value of lactate levels (LL) measured during CRS-HIPEC on postoperative outcome compared to similar major surgical procedures. Patients who were treated between January and September 2019 at our Institute and met the inclusion criteria were selected. Patients were divided into three groups: group 1: patients who underwent major surgical procedures; group 2: patients who underwent CRS without HIPEC; group 3: patients who underwent CRS with HIPEC. Intraoperative LL were analyzed and correlated with surgical procedure and postoperative outcome. We observed a significant increase of LL during surgical/CRS phase (group 1: p = 0.0001; group 2: p = 0.001; group 3: p = 0.057), rather than during the HIPEC phase in group 3 (p = ns). In patients undergoing CRS and peritonectomies, the mean LL were significantly higher compared to group 1 (p = 0.05). Although not statistically significant, the complication rate was higher in patients with end-CRS lactate values > 2 mMol/l, especially in the group undergoing CRS plus HIPEC. Our pilot study shows that higher LL during peritoneal cancer surgery are expected compared to major surgical procedures. Cytoreductive phase, rather than HIPEC, is related to an increase of LL. The role of LL as an early marker of postoperative complications after CRS-HIPEC should be further verified in properly designed studies.