Variations in Values of State, Response Entropy and Haemodynamic Parameters Associated with Development of Different Epileptiform Patterns during Volatile Induction of General Anaesthesia with Two Different Anaesthetic Regimens Using Sevoflurane in Comparison with Intravenous Induct: A Comparative Study

Adequacy of Anesthesia Guidance for Combined General/Epidural Anesthesia in Patients Undergoing Open Abdominal Infrarenal Aortic Aneurysm Repair; Preliminary Report on Hemodynamic Stability and Pain Perception

Background/Objectives: Hemodynamic instability and inappropriate postoperative pain perception (IPPP) with their consequences constitute an anesthesiological challenge in patients undergoing primary elective open lumbar infrarenal aortic aneurysm repair (OLIAAR) under general anesthesia (GA), as suboptimal administration of intravenous rescue opioid analgesics (IROAs), whose titration is optimized by Adequacy of Anaesthesia (AoA) guidance, constitutes a risk of adverse events. Intravenous or thoracic epidural anesthesia (TEA) techniques of preventive analgesia have been added to GA to minimize these adverse events. Methods: Seventy-five patients undergoing OLIAAR were randomly assigned to receive TEA with 0.2% ropivacaine (RPV) with fentanyl (FNT) 2.5 μg/mL (RPV group) or 0.2% bupivacaine (BPV) with FNT 2.5 μg/mL (BPV group) or intravenous metamizole/tramadol (MT group). IROA using FNT during GA was administered under AoA guidance. Systemic morphine was administered as a rescue agent in all groups postoperatively in the case of IPPP, assessed using the Numeric Pain Rating Score > 3. The maximum score at admission and the minimum at discharge from the postoperative care unit to the Department of Vascular Surgery, perioperative hemodynamic stability, and demand for rescue opioid analgesia were analyzed. Results: Ultimately, 57 patients were analyzed. In 49% of patients undergoing OLIAAR, preventive analgesia did not prevent the incidence of IPPP, which was not statistically significant between groups. No case of acute postoperative pain perception was noted in the RPV group, but at the cost of statistically significant minimum mean arterial pressure values, reflecting hemodynamic instability, with clinical significance < 65mmHg. Demand for postoperative morphine was not statistically significantly different between groups, contrary to significantly lower doses of IROA using FNT in patients receiving TEA. Conclusions: AoA guidance for IROA administration with FNT blunted the preventive analgesia effect of TEA compared with intravenous MT that ensured proper perioperative hemodynamic stability along with adequate postoperative pain control with acceptable demand for postoperative morphine.

Evaluating the Efficacy of Pre-Emptive Peribulbar Blocks with Different Local Anesthetics or Paracetamol Using the Adequacy of Anesthesia Guidance for Vitreoretinal Surgeries: A Preliminary Report

BACKGROUND/OBJECTIVES

Precisely selected patients require vitreoretinal surgeries (VRS) performed under general anesthesia (GA) when intravenous rescue opioid analgesics (IROA) are administered intraoperatively, despite a risk of adverse events, to achieve hemodynamic stability and proper antinociception and avoid the possibility of intolerable postoperative pain perception (IPPP). Adequacy of anesthesia guidance (AoA) optimizes the titration of IROA. Preventive analgesia (PA) techniques and intravenous or preoperative peribulbar block (PBB) using different local anesthetics (LAs) are performed prior to GA to optimize IROA. The aim was to analyze the utility of PBBs compared with intravenous paracetamol added to AoA-guided GA on the incidence of IPPP and hemodynamic stability in patients undergoing VRS.

METHODS

A total of 185 patients undergoing vitreoretinal surgery (VRS) were randomly assigned to one of several anesthesia protocols: general anesthesia (GA) with analgesia optimized through AoA-guided intraoperative remifentanil opioid analgesia (IROA) combined with a preemptive single dose of 1 g of paracetamol (P group), or PBB using one of the following options: 7 mL of an equal mixture of 2% lidocaine and 0.5% bupivacaine (BL group), 7 mL of 0.5% bupivacaine (BPV group), or 7 mL of 0.75% ropivacaine (RPV group). According to the PA used, the primary outcome measure was postoperative pain perception assessed using the numeric pain rating scale (NPRS), whereas the secondary outcome measures were as follows: demand for IROA and values of hemodynamic parameters reflecting quality or analgesia and hemodynamic stability.

RESULTS

A total of 175 patients were finally analyzed. No studied PA technique proved superior in terms of rate of incidence of IPPP, when IROA under AoA was administered (p = 0.22). PBB using ropivacaine resulted in an intraoperative reduction in the number of patients requiring IROA (p = 0.002; p < 0.05) with no influence on the dose of IROA (p = 0.97), compared to paracetamol, and little influence on hemodynamic stability of no clinical relevance in patients undergoing VRS under AoA-guided GA.

CONCLUSIONS

PA using paracetamol or PBBs, regardless of LAs used, in patients undergoing VRS proved no advantage in terms of rate of incidence of IPPP and hemodynamic stability when AoA guidance for IROA administration during GA was utilized. Therefore, PA using them seems no longer justified due to the potential, although rare, side effects.

Energy Expenditure, a New Tool for Monitoring Surgical Stress in Colorectal Oncological Patients: A Prospective, Monocentric Study

BACKGROUND

Surgical stress response in colorectal surgery consists of a neurohormonal and an immunological response and influences oncological outcomes. The intensity of surgical trauma influences mortality, morbidity, and metastasis' occurrence in colorectal neoplasia. Energy expenditure (EE) stands for the body's energy consumed to keep its homeostasis and can be either calculated or measured by direct or indirect calorimetry.

AIM

The present study attempted to evaluate surgical stress response using EE measurement and compare it to the postoperative cortisol dynamic.

METHODS

A prospective, monocentric study was conducted over a period of one year in the Anesthesiology Department including 21 patients from whom serum cortisol values were collected in the preoperative period and on the first postoperative day, and EE was measured and recorded every 15 minutes throughout surgery using the indirect calorimetry method. The study compared EE values' dynamic registered 30 minutes after intubation and 30 minutes before extubating (after abdominal closure) to cortisol perioperative dynamic.

RESULTS

We enrolled 21 patients and 84 measurements were recorded, 42 probes of serum cortisol and 42 measurements of EE. The mean value of the first measurement of serum cortisol was 13.60±3.6 µg and the second was 16.21±6.52 µg. The average value of the first EE recording was 1273.9±278 kcal and 1463.4±398.2 kcal of the second recording. The bivariate analysis performed showed a good correlation between cortisol variation and EE's variation (Spearman coefficient=0.666, p<0.001, CI=0.285, 0.865). In nine cases (42.85%), cortisol value at 24 hours reached the baseline or below the baselines preoperative value. In eight cases (38.09%), patients' EE at the end of the surgery was lower than that recorded at the beginning of the surgery.

CONCLUSIONS

Intraoperative EE variation correlated well with cortisol perioperative dynamic and stood out in this study as a valuable and accessible predictor of surgical stress in colorectal surgery.

Phase Lag Entropy as a Surrogate Measurement of Hypnotic Depth during Sevoflurane Anesthesia

Background and Objectives: Phase lag entropy, an electroencephalographic monitor, evaluates the variety in temporal patterns of phase relationship between frontal and prefrontal brain region. Phase lag entropy can reflect the depth of anesthesia induced by propofol, but the association between sevoflurane and phase lag entropy has not been elucidated. This study examined the effect of sevoflurane on phase lag entropy during induction of general anesthesia. We also explored the pharmacodynamic model between end-tidal anesthetic concentration and electroencephalographic monitor. Materials and Methods: A total of 20 patients were enrolled. General anesthesia was produced by escalating the sevoflurane (1 vol% up to 8 vol%). The relationship between phase lag entropy and end-tidal anesthetic concentration was analyzed. A non-linear mixed-effects model was used to get the relationship of pharmacodynamics between the end-tidal sevoflurane concentration and phase lag entropy. Mean blood pressure, heart rate, and the modified observer’s assessment of alertness/sedation scale were also recorded during sevoflurane anesthesia. Results: As level of sedation increased, phase lag entropy decreased. A significant correlation was showed between phase lag entropy and end-tidal sevoflurane concentration (r = −0.759, p < 0.001). The correlation coefficient between the modified observer’s assessment of alertness/sedation scale and phase lag entropy was 0.731 (p < 0.001). The pharmacodynamic factors assessed by the sigmoid Emax model were E0 = 84.9, Emax = 42, Ce50 = 1.81, γ = 4.78, and ke0 = 0.692. The prediction probability of phase-lag entropy for measuring the modified observer’s assessment of alertness/sedation scale and end-tidal sevoflurane concentration were 0.764 and 0.789, respectively. With the increasing concentration of sevoflurane, mean blood pressure decreased, but heart rate did not change. Conclusions: The continuing escalation in end-tidal sevoflurane concentration caused a decline in phase lag entropy. Phase lag entropy can serve as an indicator of hypnotic depth in patients receiving sevoflurane anesthesia.

Adequacy of Anesthesia Guidance for Colonoscopy Procedures

In patients undergoing colonoscopy procedures (CPs), inadequate dosing of hypnotic drugs (HD) and opioid analgesics (OA) during intravenous sedoanalgesia (ISA) may lead to intraprocedural awareness with recall (IAwR), intraprocedural (IPP) and postprocedural pain (PPP), as well as postoperative nausea and vomiting (PONV). The aim of this study was to evaluate whether the titration of HD and OA based on the observance of changing values of state entropy (SE) and surgical pleth index (SPI) (adequacy of anesthesia-AoA), state entropy alone, or standard practice may reduce the number of adverse events. One hundred and fifty-eight patients were included in the final analysis. The rate of IAwR and IPP was statistically more frequent in patients from the C group in comparison with the AoA and SE groups (p < 0.01 and p < 0.05, respectively). In turn, the rate of PPP, PONV, and patients' and operators' satisfaction with ISA between groups was not statistically significant (p > 0.05). Changes in hemodynamic parameters, demand for HD, and OA were statistically significant, but of no clinical value. In patients undergoing CPs under ISA using propofol and FNT, as compared to standard practice, intraprocedural SE monitoring reduced the rate of IAwR and IPP, with no influence on the rate of PPP, PONV, or patients' and endoscopists' satisfaction. AoA guidance on propofol and FNT titration, as compared to SE monitoring only, did not reduce the occurrence of the aforementioned studied parameters, imposing an unnecessary extra cost.