ABSTRACT
Background Dexmedetomidine could be a suitable adjuvant in neuroanesthesia due to its analgesic and anesthetic-sparing properties with the added advantage of facilitating intraoperative neuromonitoring. However, its recovery profile is still debated upon, as in neuroanesthesia, a prompt recovery is essential for postoperative neurologic assessment. We designed this study to evaluate the effect of dexmedetomidine on the anesthetic and recovery profile of patients presenting for supratentorial neurosurgeries. Materials and Methods Forty adult patients undergoing supratentorial surgeries were recruited in this prospective, randomized, double-blinded study and were divided into two groups: group S and group SD. Both groups received sevoflurane and fentanyl for maintenance, whereas group SD alone received a low dose of dexmedetomidine infusion. Recovery parameters, opioid consumption, Richmond Agitation-Sedation Scale (RASS) and visual analogue scale (VAS) scores, incidence of nausea and vomiting, and intraoperative hemodynamics were analyzed. Results There were no statistically significant differences between the groups S and SD in case of recovery parameters-time taken (in minutes, presented as median with interquartile range [IQR]) for (1) eye-opening to command: 9.5 (8-18) versus 22.5 (5-47.5) ( p = 0.414); 2) following verbal command: 10.5 (8.25-29.5) versus 25 (10-28.75) ( p = 0.512); (3) extubation: 11 (9.25-22) versus 25 (10-30) ( p = 0.277); and (4) getting oriented to place, time, and date: 23 (20-52.75) versus 27.5 (25-36.5) ( p = 0.121). Fentanyl consumption was significantly less in group SD (451 ± 39.3) versus group S (524.3 ± 144.1) ( p = 0.034). The median RASS score with IQR and the median VAS scores with IQR were comparable between the groups at all time points. Of the 20 patients in group S, 5 had complaints of nausea and vomiting compared with none in the group SD, although it was not statistically significant. The hemodynamic parameters did not show a significant difference between the groups except for a surge in mean arterial pressure at 30 minutes in group S. Conclusion Low-dose dexmedetomidine as an adjuvant to sevoflurane- and fentanyl-based anesthesia could provide stable hemodynamics and lesser anesthetics and opioid consumption, without adversely affecting the recovery profile in patients undergoing supratentorial neurosurgical procedures.
ABSTRACT
The association of histamine with adverse cardiac remodeling in chronic pressure overload has not received much attention. A pilot study in spontaneously hypertensive rats (SHRs) indicated a reduction of left ventricular hypertrophy (LVH) with a histamine-2-receptor (H2R) antagonist (famotidine). This finding prompted a detailed investigation of temporal variation in myocardial histamine and H2R expression and the cardiovascular response to H2R antagonism compared with that of the conventional beta-blocker metoprolol. Reduction of LVH is known to reduce the risk of adverse cardiovascular events. The myocardial histamine content and H2R expression increased with age in SHRs but not in normotensive Wistar rats. The cardiovascular response to famotidine (30 mg kg-1) was compared with that of metoprolol (50 mg kg-1) in 6-month-old male SHRs treated for 60 days. The decrease in diastolic blood pressure and improvement in cardiac function induced by famotidine and metoprolol were comparable. Both treatments caused the regression of LVH as assessed from the hypertrophy index, histomorphometry, B type natriuretic peptide (BNP), pro-collagen 1, and hydroxyproline levels. Calcineurin-A expression (marker of pathological remodeling) decreased, and Peroxiredoxin-3 expression (mitochondrial antioxidant) increased in response to the treatments. The myocardial histamine levels decreased with the treatments. The age-dependent increase in myocardial histamine and H2R in the SHRs signifies their association with progressive cardiac remodeling. The regression of LVH and improvement in cardiac function by famotidine further demonstrates the role of histamine in cardiac remodeling. Hypertrophy of cultured cardiac cells upon exposure to histamine and the H2R agonist amthamine substantiates the role of histamine in cardiac remodeling. The cardiovascular response to famotidine is comparable to that of metoprolol, suggesting repurposing of H2R antagonists for the management of hypertensive heart disease.