Efficacy of erector spine plane block in two different approaches to lumbar spinal fusion surgery: a retrospective pilot study.

Background: Erector spine plane block (ESPB) has been widely used in spinal surgery, although there are variable data about its efficacy. Objectives: This study aimed to evaluate the efficacy of ESPB in elective lumbar spinal fusion surgery patients with two different surgical approaches. Materials and methods: Retrospectively, 45 elective lumbar transpedicular fusion (TPF) surgery patients undergoing open surgery with different approaches [posterior transforaminal fusion approach (TLIF) or combined posterior and anterior approach (TLIF+ALIF)] were divided into 2 groups: general anesthesia (GA, n = 24) and general anesthesia combined with ESPB (GA + ESPB, n = 21). The primary outcome was to analyze the efficacy of ESPB in two different surgical approaches in terms of pain intensity in the first 48 h. Secondary: Fentanyl-free patients and opioid consumption in the first 24 h postoperatively. Comparative analysis was performed (SPSS® v. 28.0) (p < 0.05). Results: Out of 45 patients (27 female), 21 received GA + ESPB and 24 received GA. The average age was 60.3 ± 14.3 years. Chronic back pain before the operation was registered in 56% of patients. ESPB was performed in 17 TLIF and in 4 TLIF+ALIF patients. ESPB significantly reduced pain intensity at rest in both surgical approaches 48 h after surgery (p < 0.05). The need for postoperative fentanyl infusion was significantly lower in the group treated with GA + ESPB in both surgical approaches than in those who only received GA (29% vs. 77% in TLIF and 0% vs. 80% in TLIF+ALIF); p = 0.01 and p = 0.004. Additionally, we observed that ESPB provides a good analgesic effect for up to 6.8 ± 3.2 h in the TLIF and 8.9 ± 7.6 h in the TLIF+ALIF approaches. Consequently, ESPB reduced the initiation of the fentanyl compared to GA alone, with a mean difference of 3.2 ± 4.2 h in the TLIF subgroup (p = 0.045) and 6.7 ± 5.3 h in TLIF +ALIF (p = 0.028). Only in the TLIF+ALIF approach, ESPB reduced the total fentanyl consumption compared to those with GA (1.43 ± 0.45 mg/24 h vs. 0.93 ± 0.68 mg/24 h; p = 0.015). Conclusion: ESPB significantly reduced pain at rest after surgery, the number of patients requiring immediate postoperative fentanyl analgesia, and total fentanyl consumption in both surgical approaches, particularly in TLIF+ALIF. However, the application of ESPB does not always provide completely sufficient analgesia.

Volume kinetic analysis of fluid retention after induction of general anesthesia.

BACKGROUND: Induction of general anesthesia increases the hemodilution resulting from infusion of crystalloid fluid, which is believed to be due to slower distribution caused by arterial hypotension. When normal distribution returns is not known. METHODS: An intravenous infusion of 25 mL kg- 1 of Ringer's lactate was infused over 30 min to 25 volunteers just after induction of general anesthesia for open abdominal hysterectomy. A two-volume model was fitted to the repeated measurements of the blood hemoglobin concentration and the urinary excretion using mixed-effects modelling software. Individual-specific covariates were added in sequence. RESULTS: Distribution of infused fluid was interrupted during the first 20 min of the infusions. During this time 16.6 mL kg- 1 of lactated Ringer's had been infused, of which virtually all remained in the circulating blood. Thereafter, the fluid kinetics was similar to that previously been found in awake volunteers except for the elimination rate constant (k10), which remained to be very low (0.86 × 10- 3 min- 1). Redistribution of infused fluid from the interstitium to the plasma occurred faster (higher k21) when the arterial pressure was low. No covariance was found between the fixed parameters and preoperatively concentrated urine, the use of sevoflurane or propofol to maintain the anesthesia, or the plasma concentrations of two degradation products of the endothelial glycocalyx, syndecan-1 and heparan sulfate. CONCLUSIONS: Induction of general anesthesia interrupted the distribution of lactated Ringer's solution up to when 16.6 mL kg- 1 of crystalloid fluid had been infused. Plasma volume expansion during this period of time was pronounced. TRIAL REGISTRATION: Controlled-trials.com (ISRCTN81005631) on May 17, 2016 (retrospectively registered).

Hypervolemia does not cause degradation of the endothelial glycocalyx layer during open hysterectomy performed under sevoflurane or propofol anesthesia.

BACKGROUND: Fluid-induced hypervolemia may stimulate the release of natriuretic peptides and cause degradation (shedding) of the endothelial glycocalyx layer. Sevoflurane is believed to protect the glycocalyx, but the importance of using sevoflurane to prevent shedding during routine surgery is unclear. METHODS: The plasma concentrations of brain natriuretic peptide and two biomarkers of glycocalyx shedding, syndecan-1, and heparan sulfate, were measured in 26 patients randomized to receive general anesthesia with sevoflurane or propofol during open abdominal hysterectomy. The fluid therapy consisted of 25 mL/kg (approximately 2 L) of Ringer´s lactate over 30 minutes. Blood hemoglobin and plasma albumin were used to indicate plasma volume expansion and capillary leakage. RESULTS: The plasma concentrations of brain natriuretic peptide and shedding products showed low levels throughout the surgery (median brain natriuretic peptide, 21 ng/L; syndecan-1, 12.9 ng/mL; and heparan sulfate, 6.5 µg/mL), but the heparan sulfate concentration increased 2 hours post-operatively (to 17.3 µg/mL, P < .005). No differences were noted between the propofol and sevoflurane groups in any of the measured parameters. Albumin was apparently recruited to the bloodstream during the first 20 minutes, when the intravascular retention of infused fluid was almost 100%. The urine flow was <1 mL/min, despite the vigorous volume loading. CONCLUSIONS: No relevant elevations of brain natriuretic peptide or degradation products of the glycocalyx layer were observed when hypervolemia was induced during open abdominal hysterectomy performed with sevoflurane or propofol anesthesia. Plasma volume expansion from Ringer´s lactate was pronounced.

Fibrinolytic System Changes in Liver Surgery: A Pilot Observational Study.

Introduction: Bleeding occurs frequently in liver surgery. Unbalance between tissue plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1) concentrations might increase bleeding. Our aim was to analyze perioperative fibrinolytic changes during liver surgery. Materials and Methods: We evaluated 15 patients for inclusion into a prospective pilot study of liver surgery. We assessed fibrinolysis by plasma PAI-1 and t-PA: before surgery (T1), before Pringle maneuver (PM;T2), at the end of surgery (T3) and 24 h postoperatively (T4), and registered demographic and laboratory data, extent and duration of surgery, hemodynamic parameters, blood loss, and transfused volumes of blood products. Data presented as mean ± SD. Significance at P < 0.05. Results: After exclusion of six patients only undergoing biopsies, we included six women and three men aged 49.1 ± 19.6 years; two patients with liver metastases of colorectal cancer and hepatocellular carcinoma, respectively, two with focal nodular hyperplasia, two with hepatic hemangioma, and one with angiomyolipoma. Six patients underwent PM. PAI-1 plasma concentration (n = 9) rose from 6.25 ± 2.25 at T1 through 17.30 ± 14.59 ng/ml at T2 and 28.74 ± 20.4 (p = 0.007) and 22.5 ± 16.0 ng/ml (p = 0.04), respectively, at T3 and T4. Correspondingly, t-PA plasma concentration (n = 9) increased from 4.76 ± 3.08 ng/ml at T1 through 8.00 ± 5.10 ng/ml (p = 0.012) at T2 and decreased to 4.25 ± 2.29 ng/ml and 3.04 ± 3.09 at T3 and T4, respectively. Plasma t-PA level at T2 was significantly different from those at T1, T3, and T4 (p < 0.004). In PM patients, t-PA levels increased from T1, peaked at T2 (p = 0.001), and subsequently decreased at T3 and T4 (p = 0.011 and p = 0.037), respectively. Mean blood loss was 1,377.7 ± 1,062.8 ml; seven patients received blood products. Patients with higher PAI-1 levels at T3 received more fresh frozen plasma (r = 0.79; p = 0.01) and red blood cells (r = 0.88; p = 0.002). Conclusions: During liver surgery, fibrinolysis increased, as evidenced by rises in plasma PAI-1and t-PA, especially after start of surgery and following PM. Transfused volumes of blood products correlated with higher plasma concentrations of PAI-1. Confirming this tendency requires a larger cohort of patients.

Minimal shedding of the glycocalyx layer during abdominal hysterectomy.

BACKGROUND: Surgery with and without hypervolaemia may cause shedding (breakdown) of the endothelial glycocalyx layer, but the severity of this problem is unclear. METHODS: In this preliminary report of a larger clinical trial, the plasma and urine concentrations of three biomarkers of glycocalyx shedding (syndecan-1, hyaluronic acid and heparan sulfate) were measured in seven patients before, during, and after open hysterectomy. The fluid therapy consisted of 25 ml/kg (approximately 2 l) of Ringer's lactate, which was infused over 30 min when the surgery started. The resulting plasma volume expansion at the end of the infusion was estimated from the haemodilution. RESULTS: The mean plasma concentration of syndecan-1 was 21.7 ng/ml before surgery and averaged 19.7 ng/ml during and after the surgery. The plasma concentration of hyaluronic acid decreased from 38.0 to 27.7 ng/ml (P < 0.05), while heparan sulfate increased from 3.4 to 5.5 µg/ml (P < 0.05). The urine concentrations of syndecan-1 decreased significantly, while they increased for hyaluronic acid and heparan sulfate. Despite the vigorous fluid load, the urine flow did not exceed 1 ml/min. CONCLUSIONS: No clear evidence was found for shedding of the endothelial glycocalyx layer when 2 l of Ringer's lactate was infused over 30 min during abdominal hysterectomy. Urine analyses yielded patterns of changes that differed from those in plasma. TRIAL REGISTRATION: ISRCTN81005631 . Registered May 17, 2016.