Abstract
General anesthesia decreases the tone of upper airway muscles in a dose-dependent fashion, potentially narrowing the pharyngeal airway. We examined the effects of adding ketamine on the airway configuration after dexmedetomidine administration in spontaneously breathing children with normal airways. 25 children presenting for Magnetic Resonance Imaging (MRI) of the brain/spine under general anesthesia were prospectively recruited in the study. Patients were anesthetized with dexmedetomidine bolus (2 mcg over 10 min) followed by dexmedetomidine infusion (2 mcg·kg·h) and ketamine and permitted to breathe spontaneously via the native airway. MR-CINE images of the upper airway were obtained with dexmedetomidine infusion alone (baseline) and 5, 10, and 15 min after administering ketamine bolus (2 mg·kg) in two anatomical axial planes at the nasopharynx and the retroglossal upper airway. Airway lumen is segmented with a semi-automatic image processing approach using a region-growing algorithm. Outcome measures of cross-sectional area, transverse and anterior-posterior diameters of the airway in axial planes at the level of the epiglottis in the retroglossal airway, and in the superior nasopharynx were evaluated for changes in airway size with sedation. Airway dimensions corresponding to the maximum, mean, and minimum sizes during a respiratory cycle were obtained to compare the temporal changes in the airway size. The dose-response of adding ketamine to dexmedetomidine alone condition on airway dimensions were examined using mixed-effects of covariance models. 22/25 patients based on inclusion/exclusion criteria were included in the final analysis. The changes in airway measures with the addition of ketamine, when compared to the baseline of dexmedetomidine alone, were statistically insignificant. The modest changes in airway dimensions are clinically less impactful and within the accuracy of the semi-automatic airway segmentation approach. The effect sizes were small for most airway measures. The duration of ketamine seems to not affect the airway size. In conclusion, adding ketamine to dexmedetomidine did not significantly reduce upper airway configuration when compared to dexmedetomidine alone.
Highlights
The unique sedative properties of dexmedetomidine (DEX) have renewed interest in the study and use of alpha 2-adrenoceptor agonists as sedatives and/or adjuncts to anesthesia in a variety of pediatric procedures [1,2,3]
Combining ketamine with dexmedetomidine has been studied in adults and children for drug-induced sleep endoscopy (DISE) [12], extracorporeal shock wave lithotripsy [13], lumbar puncture [14], bone marrow biopsy, burn dressing changes [15,16], chest tube insertion, and femoral cut-down for tunneled central venous catheter placement [17]
We hypothesized that adding ketamine to dexmedetomidine would not significantly reduce airway caliber or morphology when compared with dexmedetomidine alone
Summary
The unique sedative properties of dexmedetomidine (DEX) have renewed interest in the study and use of alpha 2-adrenoceptor agonists as sedatives and/or adjuncts to anesthesia in a variety of pediatric procedures [1,2,3]. Dexmedetomidine induced sedation mimics the physiologic changes seen during non-rapid-eye-movement sleep through its action on alpha 2-adrenergic receptors in the locus ceruleus. Administering high doses of dexmedetomidine to provide adequate sedation for procedures may lead to significant hemodynamic instability, bradycardia, and swings in mean arterial pressure. Combining ketamine with dexmedetomidine has been studied in adults and children for drug-induced sleep endoscopy (DISE) [12], extracorporeal shock wave lithotripsy [13], lumbar puncture [14], bone marrow biopsy, burn dressing changes [15,16], chest tube insertion, and femoral cut-down for tunneled central venous catheter placement [17]
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.