A Randomized Double-Blind Controlled Trial to Assess the Efficacy of Ultrasound-Guided Erector Spinae Plane Block in Cardiac Surgery.

OBJECTIVE: Cardiac surgical pain is of moderate-to-severe intensity. Ineffective pain control may lead to increased cardiopulmonary complications and poor surgical outcomes. This study aimed to assess the efficacy of ultrasound-guided erector spinae plane block in providing analgesia in adult cardiac surgeries. DESIGN: Prospective, randomized, double-blinded clinical trial. SETTINGS: Single-center, tertiary care hospital with university affiliation. PARTICIPANTS: Thirty patients of either sex, aged 18-to-60 years, body mass index 19-to-30 kg/m2, undergoing elective on-pump single-vessel coronary artery bypass grafting or valve replacement under general anesthesia. INTERVENTIONS: Patients were randomly categorized into two groups of 15 patients each to receive bilateral erector spinae plane block with 20 mL per side of 0.25% levobupivacaine (group E) or sham block with 20 mL of normal saline (group C). MAIN RESULTS: Mean analgesic requirement in terms of fentanyl equivalents (µg) in the first 24 hours postoperatively was 225 ± 112 in group E and 635 ± 145 in group C (95% confidence interval, 313.10-506.90; p < 0.05). Mean time to first rescue analgesia was 356.9 ± 34.5 in group E and 123.9 ± 13.1 minutes in group C (p < 0.05). Cox proportional hazard ratio for rescue analgesic requirement in group E-to-group C was 5.0. Duration of mechanical ventilation was 88.4 ± 17 and 103.5 ± 18 minutes in groups E and C, respectively (p < 0.05). Ramsay sedation score at six hours postextubation was 1.45 ± 0.53 in group E and 3.19 ± 0.62 in group C (p < 0.05). Mean numerical rating score was 3.67 ± 1.41 in group E and 4.50 ± 1.00 in group C (p = 0.17). No significant differences were observed in the incidences of postoperative nausea vomiting, pruritus, and erector spinae plane block-related infection and pneumothorax. CONCLUSION: Single-shot erector spinae plane block provides superior analgesia as compared with sham block. It decreased the first 24-hour postoperative analgesic consumption by 64.5% and risk of pain by five times in the authors' population. It also reduced the sedation and duration of mechanical ventilation in postcardiac surgery patients.

Realization of Microfluidic Preconcentrator for N-Pentane Traces Impurities from the Gaseous Media.

In this paper, we present the work of designing and fabricating a new generation of microelectromechanical systems (MEMS) based microfluidic preconcentrators (MFP) for volatile organic compounds (VOCs) quantification. The main objective of this work is to quantify the n-pentane impurities using MFP for sample preparation. The MFP was analyzed using Hewlett-Packard 5890 gas chromatography, having a flame ionization detector under isothermal conditions. The proposed MFP system includes two-microfluidic preconcentrators for continuous action and a system of four 3/2 solenoid valves with a control unit. Microfluidic preconcentrators were placed on metal plates and have circular channels filled with Al2O3 (50 µm), n-octane ResSil-C (80/100 mesh) sorbents of one nature and are hyphenated with the Peltier elements to regulate the temperature of sorption and desorption. The n-pentane quantitative determination was carried out using a calibration plot of gas mixtures on a successive dilution with the nitrogen. This study shows that the microfluidic preconcentrator system with Al2O3 and n-Octane ResSil-C sorbent concentrates the n-pentane traces up to 41 to 47 times from the gas mixture with the standard deviation of ≤5%. It has been observed that the n-octane ResSil-C based MFC shows very fast response (<5 min) and stability up to 300 cycles.