Evaluation of dynamic cerebrovascular autoregulation during liver transplantation.

BACKGROUND: Cerebrovascular autoregulation in patients with acute and chronic liver failure is often impaired, yet an intact autoregulation is essential for the demand-driven supply of oxygenated blood to the brain. It is unclear, whether there is a connection between cerebrovascular autoregulation during liver transplantation (LTX) and the underlying disease, and if perioperative anesthesiologic consequences can result from this. METHODS: In this prospective observational pilot study, data of twenty patients (35% female) undergoing LTX were analyzed. Cerebral blood velocity was measured using transcranial doppler sonography and was correlated with arterial blood pressure. The integrity of dynamic cerebrovascular autoregulation (dCA) was evaluated in the frequency domain through transfer function analysis (TFA). Standard clinical parameters were recorded. Mixed one-way ANOVA and generalized estimating equations were fitted to data involving repeated measurements on the same patient. For all other correlation analyses, Spearman's rank correlation coefficient (Spearman's-Rho) was used. RESULTS: Indications of impaired dCA are seen in frequency domain during different phases of LTX. No correlation was found between various parameter of dCA and primary disease, delirium, laboratory values, length of ICU or hospital stay, mortality or surgical technique. CONCLUSIONS: Although in most cases the dCA has been impaired during LTX, the heterogeneity of the underlying diseases seems to be too diverse to draw valid conclusions from this observational pilot study.

Pain management after robot-assisted minimally invasive esophagectomy.

Background: Adequate pain control after open esophagectomy is associated with reduced complications, earlier recovery and higher patient satisfaction. While further developing surgical procedures like robot-assisted minimally invasive esophagectomy (RAMIE) it is relevant to adapt postoperative pain management. The primary question of this observational survey was whether one of the two standard treatments, thoracic epidural analgesia (TEA) or intravenous patient-controlled analgesia (PCA), is superior for pain control after RAMIE as the optimal pain management for these patients still remains unclear. Use of additional analgesics, changes in forced expiratory volume in 1 s (FEV1), postoperative complications and duration of intensive care and hospital stay were also analyzed. Methods: This prospective observational pilot study analyzed 50 patients undergoing RAMIE (postoperative PCA with piritramide or TEA using bupivacaine; each n = 25). Patient reported pain using the numeric rating scale score and differences in FEV1 using a micro spirometer were measured at postoperative day 1, 3 and 7. Additional data of secondary endpoints were collected from patient charts. Results: Key demographics, comorbidity, clinical and operative variables were equivalently distributed. Patients receiving TEA had lower pain scores and a longer-lasting pain relief. Moreover, TEA was an independent predictive variable for reduced length of hospital stay (HR -3.560 (95% CI: -6.838 to -0.282), p = 0.034). Conclusions: Although RAMIE leads to reduced surgical trauma, a less invasive pain therapy with PCA appears to be inferior compared to TEA in case of sufficient postoperative analgesia and length of hospital stay. According to the results of this observational pilot study analgesia with TEA provided better and longer-lasting pain relief compared to PCA. Further randomized controlled trials should be conducted to evaluate the optimal postoperative analgesic treatment for RAMIE.

Influence of intraoperative fluid replacement on ampicillin serum levels and surgical site infections.

BACKGROUND: Surgical site infections (SSI) occur despite antimicrobial prophylaxis and increase postoperative morbidity and mortality. This could be caused by an intraoperative decrease in antibiotic serum concentrations such as ampicillin after major abdominal surgery due to blood loss and fluid therapy, which possibly promotes SSI. This hypothesis was tested in the present study. METHODS: This pilot study was performed as a prospective observational trial between March 2018 and May 2019. Ampicillin/sulbactam was administered intravenously during anesthesia induction. Fluid replacement was guided based on hemodynamic variables, including analysis of pulse pressure variation. The primary outcome was ampicillin serum level (ASL), measured after administration and hourly within 4 hours. The incidence of SSI at hospital discharge was the secondary outcome. Linear mixed and logistic regression models were used for statistical analyses. RESULTS: After screening of 133 adult patients, 129 were enrolled, and 102 completed the study protocol. No correlation was found between the volume of intraoperative fluids and ASL, nor was any association found between ASL and SSI. Based on 5 SSI cases, SSI were associated with higher intraoperative fluid volume. ASL was sufficient to provide intraoperative coverage for all potential bacterial strains. CONCLUSION: Intraoperative fluid replacement had no effect on ASL up to 4 hours after ampicillin/sulbactam administration. SSI were within an acceptable range, indicating adequate antimicrobial prophylaxis, so intraoperative control of ASL does not seem necessary. In conclusion, contrary to our initial hypothesis, ASL is not influenced by volume turnover or blood loss during major surgery and therefore does not affect SSI.