The Effectiveness of Dexmedetomidine as a Prophylactic Treatment for Emergence Delirium Among Combat Veterans With High Anxiety: A Randomized Placebo-Controlled Trial.

INTRODUCTION: Emergence delirium (ED) is characterized by agitation, confusion, and violent physical and verbal behavior associated with awakening from general anesthesia. Combat exposure among U.S. military veterans has been identified as a risk factor for ED. Preoperative baseline anxiety was shown to be a predictor of ED, and combat veterans are known to be at high risk for anxiety as well as depression and PTSD. Dexmedetomidine is an alpha-2 receptor agonist proven to mitigate ED in several patient populations. Perioperative use of dexmedetomidine demonstrated promising benefits in pediatric ED but has not been evaluated in combat veterans. MATERIALS AND METHODS: This study was a multi-site, prospective, randomized controlled investigation of 369 patients with a history of military combat exposure who were scheduled for elective surgery with a general anesthetic as the primary means of anesthesia. The trial was funded by the Tri-Service Nursing Research Program Grant HU0001-14-TS05 (N14-PO3) and approved by the Institutional Review Boards at the Naval Medical Center San Diego, Womack Army Medical Center, Walter Reed National Military Medical Center, and the Uniformed Services University of the Health Sciences, Bethesda, MD. All subjects were administered the State-Trait Anxiety Inventory (STAI) to evaluate baseline anxiety. Those enrolled subjects with a low anxiety level (STAI < 39) (n = 215) were placed in the observational arm of the study. Those with a high anxiety level (STAI ≥ 39) were placed in the experimental arm (n = 153) and were further randomized to treatment with intraoperative dexmedetomidine infusion (1 µg/kg bolus at induction, followed by a 0.6 µg/kg/h infusion continued until emergence) (n = 75) or a placebo intraoperative infusion (n = 75). Following the delivery of the prescribed anesthetic, all subjects were observed for signs of ED using the Pediatric Anesthesia Emergence Delirium (PAED) Scale. The patient and data recorder remained blinded to the randomization results. RESULTS: The central tendencies of demographics and clinical characteristics are reported. PAED among those randomized to dexmedetomidine (median 7, interquartile interval (IQI) 5.2-9.2) tended to be less (P < .0001) than that of those randomized to control (median 12, IQI 10-13). Dexmedetomidine was found to be the most important predictor of PAED (35% relative importance), followed by Patient Health Questionnaire (14%), STAI-Trait (9%), and PTSD Checklist-Military Version (8%); the overall rankings are featured. Randomization to receipt of dexmedetomidine was associated with a 3.7-unit reduction (95% CI 2.5-4.9) in PAED (P < .001) in a linear model controlling for several variables, and the directionality of the effect persisted upon regularization in a penalized linear model. CONCLUSIONS: Dexmedetomidine was effective at reducing PAED among combat veterans who were experiencing symptoms of pre-operative anxiety (i.e., STAI-State ≥39). Although psychological morbidity is not unique to the military population, combat veterans carry some of the highest rates of anxiety, PTSD and depression compared to the general population. Dexmedetomidine can be safety employed by anesthesia providers to reduce symptoms of ED in the perioperative period. The double-blind randomized, controlled study design strengthens our analyses; however, this study did not control for the type of surgical procedure or the duration of anesthetic. Furthermore, we only enrolled patients with combat exposure experiencing symptoms of anxiety and did not investigate the role of dexmedetomidine in combat veterans with less anxiety. Further study of the relationship between psychological comorbidities, ED, and dexmedetomidine is warranted.

Utility of the Berlin Questionnaire to screen for obstructive sleep apnea among patients receiving intravenous sedation for colonoscopy.

UNLABELLED: Obstructive sleep apnea (OSA) affects approximately 20% of Americans. Patients with undiagnosed OSA may experience obstructive episodes during conscious sedation for colonoscopy. The purpose of this investigation was to describe the risk of undiagnosed OSA using the Berlin Questionnaire and to identify the relationship between OSA risk and the number of provider interventions performed to relieve obstructive symptoms during sedation for colonoscopy. METHODS: Adult patients were enrolled from the gastroenterology clinic at the National Military Medical Center (N = 99). The Berlin Questionnaire was delivered and a brief health history obtained. Patients were observed for obstructive symptoms during sedation. Provider interventions were counted. 18 patients were monitored during their first night of sleep using a portable sleep monitor. Data were analyzed using the independent samples t-test, Chi-square, and Chi-square test for trend. RESULTS: The incidence of undiagnosed OSA was 40.4%. Patients with hypertension had a higher rate of a positive screen for OSA (70%) than those without hypertension (20.3%), chi2(1) = 3.87, P < .05. There was no statistical difference in the number of provider interventions between the 2 groups. Risk of undiagnosed OSA in this sample is large but it does not appear to be associated with episodes of obstructive symptoms requiring provider intervention.

The incidence of and risk factors for emergence delirium in U.S. military combat veterans.

The purpose of this research was to identify the incidence and potential risk factors for emergence delirium (ED) in a U.S. military combat veteran surgical population at Naval Hospital Camp Pendleton. ED is a postanesthetic phenomenon that occurs immediately after emergence from general anesthesia and is characterized by agitation, confusion, and violent behavior. Clinical evidence suggests that ED is increasingly seen among military personnel returning from the wars in Iraq and Afghanistan, and that the incidence of anxiety, depression, and post-traumatic stress disorder (PTSD) are higher in this population than in noncombat troops or nonmilitary populations. The incidence of ED in this sample of 130 postoperative military personnel with combat exposure was 20% (n=26). Those previously diagnosed with a psychological disorder had a higher rate of ED (50%) than those who did not (17.5%), χ(2)=5.53, P<.05. There was a positive relationship between ED in veterans who reported greater amounts of anxiety, PTSD symptoms, and depression [state anxiety: r(128)=0.40, P<.001; trait anxiety: r(128)=0.40, P<.001; PTSD: r(128)=0.35, P<.001; and depression: r(128)=0.25, P=.002]. This study revealed the incidence of ED and identified anxiety, PTSD, and depression as risk factors. Regression modeling suggested that state-anxiety served as the best predictor. These findings increase clinicians' understanding of ED among combat veterans and give direction to future studies that should focus on preventive treatment.

Risk factors for emergence delirium in U.S. military members.

Emergence delirium (ED) is a postanesthesia phenomenon occurring in both adults and children during recovery from general anesthesia. Although the pediatric population has been an ongoing focus of research and publications regarding ED, a renewed interest in ED has developed among military nurses and anesthesia providers because of its increasing incidence among the US military surgical population. The purpose of this article is to identify potential risk factors for emergence delirium in the US military population. Possible relationships between the physiological and psychological changes in US military veterans and the surgical experience are explored. A review of ED as it occurs among the pediatric, adult, and elderly populations is also provided to support potential etiologies for the occurrence of ED in the military population. Pain and physical and psychological trauma as a result of military duty are identified and linked to ED as potential risk factors. Identification of these risk factors may provide guidance for scientific inquiry into this phenomenon in the military population. Implications for future study are also explored.