Definitions and pathophysiology of vasoplegic shock.

Vasoplegia is the syndrome of pathological low systemic vascular resistance, the dominant clinical feature of which is reduced blood pressure in the presence of a normal or raised cardiac output. The vasoplegic syndrome is encountered in many clinical scenarios, including septic shock, post-cardiac bypass and after surgery, burns and trauma, but despite this, uniform clinical definitions are lacking, which renders translational research in this area challenging. We discuss the role of vasoplegia in these contexts and the criteria that are used to describe it are discussed. Intrinsic processes which may drive vasoplegia, such as nitric oxide, prostanoids, endothelin-1, hydrogen sulphide and reactive oxygen species production, are reviewed and potential for therapeutic intervention explored. Extrinsic drivers, including those mediated by glucocorticoid, catecholamine and vasopressin responsiveness of the blood vessels, are also discussed. The optimum balance between maintaining adequate systemic vascular resistance against the potentially deleterious effects of treatment with catecholamines is as yet unclear, but development of novel vasoactive agents may facilitate greater understanding of the role of the differing pathways in the development of vasoplegia. In turn, this may provide insights into the best way to care for patients with this common, multifactorial condition

A comparative study of landmark-based topographic method versus the formula method for estimating depth of insertion of right subclavian central venous catheters

Background and Aims: Subclavian central venous catheterisation (CVC) is employed in critically ill patients requiring long-term central venous access. There is no gold standard for estimating their depth of insertion. In this study, we compared the landmark topographic method with the formula technique for estimating depth of insertion of right subclavian CVCs. Methods: Two hundred and sixty patients admitted to Intensive Care Unit requiring subclavian CVC were randomly assigned to either topographic method or formula method (130 in each group). Catheter tip position in relation to the carina was measured on a post-procedure chest X-ray. The primary endpoint was the need for catheter repositioning. Mann–Whitney test and Chi-square test was performed for statistical analysis using SPSS for windows version 18.0 (Armonk, NY: IBM Corp). Results: Nearly, half the catheters positioned by both the methods were situated >1 cm below the carina and required repositioning. Conclusion: Both the techniques were not effective in estimating the approximate depth of insertion of right subclavian CVCs

Efficacy of dexmedetomidine with ropivacaine in supraclavicular brachial plexus block for upper limb surgeries

Background and Aims: The primary aim of this study was to evaluate the effect of addition of dexmedetomidine on the duration of analgesia in patients undergoing upper limb surgeries under supraclavicular brachial plexus block. Material and Methods: Sixty patients of American Society of Anesthesiologists physical status I/II/III undergoing elective upper limb surgeries under supraclavicular brachial plexus block using nerve stimulator were randomized into two groups. Group A (n = 30) received 30 mL 0.5% ropivacaine and 1 mL normal saline, and Group B (n = 30) received 30 mL 0.5% ropivacaine and 1 μg/kg of dexmedetomidine. The primary outcome was the duration of analgesia. Secondary outcomes included time to onset and duration of sensory/motor blockade. Statistical Analysis: Results on continuous measurements are presented as mean ± standard deviation and compared using Student's unpaired t-test. Results on categorical measurements are presented in number (%) and compared using Chi-square test. Results: Onset of sensory and motor block in Group A (13.0 ± 4.1 and 23.5 ± 5.6 min) was slower than those in Group B (9.5 ± 5.8 and 15.6 ± 6.3 min; P = 0.009 for sensory and P < 0.001 for the motor block). Duration of sensory and motor block in Group A (400.8 ± 86.6 and 346.9 ± 76.9 min) was shorter than those in Group B (630.6 ± 208.2 and 545.9 ± 224.0 min; (P < 0.001). The duration of analgesia in Group A (411.0 ± 91.2 min) was shorter than that in Group B (805.7 ± 205.9 min; P < 0.001). The incidence of bradycardia and hypotension was higher in Group B than in Group A (P < 0.001). Conclusion: Perineural dexmedetomidine with ropivacaine provides prolonged postoperative analgesia, hastens the onset of sensory and motor block and prolongs the duration of the supraclavicular brachial plexus block

Cervical dilatation in parturient receiving neuraxial analgesia: Comparison of epidural analgesia alone with combined spinal epidural analgesia

Background: Both epidural analgesia and combined spinal epidural analgesia (CSEA) are employed for pain relief during labor because they provide reliable analgesia compared to other modalities. Studies are equivocal with respect to their effect on the rate of cervical dilatation, duration of labor, and labor outcome. The primary outcome of the present study was to compare the effect of epidural analgesia alone with CSEA with respect to the rate of cervical dilatation. Materials and Methods: One hundred and twenty parturients with an initial cervical dilatation of <4 cm were randomized to receive CSEA or epidural analgesia alone for pain relief during labor. The rate of cervical dilatation, onset of effective analgesia, number of epidural top-ups requested, labor outcome, and the quality of analgesia was assessed in both the study groups. Statistical Analysis: Mann–Whitney and Chi-square tests were performed where applicable to compare the data between the two groups. Results: The results of the study showed that the rate of cervical dilatation was rapid with CSEA compared to epidural analgesia alone [median (interquartile range) 2 (1.2,3) v/s 1.16 (1,2)]. The onset of analgesia was earlier with combined spinal epidural (CSE v/s EA, 3.7 ± 1.3 min v/s 23.8 ± 5.8 min). Labor outcome and quality of analgesia was similar between the two groups. The incidence of pruritus was higher with CSEA than with epidural analgesia alone. Conclusion: CSEA is associated with more rapid cervical dilatation and shorter duration of first stage of labor when compared with epidural analgesia alone