Effects of pneumoperitoneum on hemodynamics evaluated by continuous noninvasive arterial pressure monitoring. A single-center observational study.

BACKGROUND AND OBJECTIVES: The induction of pneumoperitoneum (PP) during laparoscopy may cause hemodynamic alterations, especially in patients with unknown cardiovascular diseases. While invasive arterial monitoring could be considered excessive, continuous noninvasive arterial pressure (CNAP) monitoring may allow careful evaluation of hemodynamic variations during laparoscopy. MATERIALS AND METHODS: The objective of this single center observational study was to evaluate hemodynamic changes after insufflation and after deflation of PP with CNAP monitoring. Patients included where adults undergoing elective laparoscopic cholecystectomy (American Society of Anesthesiologists physical status classification II and III). The Hemodynamic data (blood-pressure, cardiac-index, heart-rate, stroke-volume index, stoke-volume variation and arterialelastance) were collected 30 seconds before pneumoperitoneum (t1), and compared to values at 2 (t2), 10 (t3) and 20 (t4) minutes after pneumoperitoneum insufflation. We also compared data 30 seconds before and 2 minutes after release of pneumoperitoneum. RESULTS: 65 patients were included. Compared with reference values at t1, blood-pressure values increased at all timepoints (t2-t3-t4); cardiac-index augmented at t3 and t4 (p<0.05); heart-rate increased at t3 (p<0.005); stroke-volume index decreased at t2 (p<0.005) and was higher at t4 (p<0.005). While stoke-volume variation remained always stable after pneumoperitoneum induction, arterial-elastance increased significantly at all time-points (t2-t3-t4). The only difference at pneumoperitoneum deflation was a reduction in stoke-volume variation (p<0.05). CONCLUSIONS: In patients undergoing elective cholecystectomy, CNAP monitoring showed significant hemodynamic changes that would have been underappreciated with standard non-invasive monitoring with increase in arterial elastance under stable preload conditions. Whether this effect is due to unknown cardiovascular diseases facilitating ventriculo-arterial decoupling remains to be determined. KEY WORDS: Arterial Elastance, Cardiac Outp, Pneumoperitoneum, Stroke Volume, Stroke Volume Variation.

α-2 agonists vs. fentanyl as adjuvants for spinal anesthesia in elective cesarean section: a meta-analysis.

INTRODUCTION: Elective cesarean section (CS) is usually performed using spinal anesthesia (SA), which requires the use of local anesthetic (LA) agents, commonly combined with adjuvant drugs. We performed a systematic review and meta-analysis aimed at studying the advantages of α-2 agonists as compared to fentanyl during SA for CS. EVIDENCE ACQUISITION: We screened PubMed and EMBASE for randomized controlled trials (RCTs). We calculated the mean difference (MD) for continuous outcomes, and the relative risk for dichotomous outcomes, using a random-effect model with 95% confidence interval (CI). We performed a Trial Sequential Analysis (TSA) assuming an alpha risk of 5%. The primary outcome was the time to first rescue analgesia. EVIDENCE SYNTHESIS: Eight RCTs were included. Time to first rescue analgesia was significantly longer when the α-2 agonists were used (MD 85.9 min [95% CI: 23.8, 147.9]; P=0.007). Duration of sensory block was also longer in the α-2 group (MD 40.5 [95% CI: 20.21,60.7]; P<0.0001), while no differences were found for onset of sensory block and onset and duration of motor block. Rates of shivering and nausea or vomiting were significantly lower in the α-2 agonist group, while risk of hypotension or respiratory depression were not different. The TSA on the primary outcome suggests the need of further research before drawing conclusions. CONCLUSIONS: α2-agonists seem to increase the time to first rescue analgesia and to prolong the duration of sensory block when used as adjuvants to LA in CS patients compared to fentanyl. Also, α2-agonists may reduce the incidence of shivering and nausea or vomiting.