Randomized clinical trial of capnometry-assisted respiratory training in veterans with posttraumatic stress disorder hyperarousal.

OBJECTIVE: To investigate whether capnometry-assisted antihyperventilation respiratory training, successful in treating panic, and sleep hygiene instructions would reduce posttraumatic stress disorder (PTSD) hyperarousal symptoms in U.S. military veterans. METHOD: We conducted a parallel, nonblinded clinical trial and randomized 80 veterans with PTSD hyperarousal into treatment or wait list. Primary treatment outcomes from baseline to 1st follow-up were analyzed using mixed modeling. Baseline physiological measures were compared between the PTSD hyperarousal group and a no-PTSD group (n = 68). RESULTS: Baseline respiration rate but not partial-pressure of end-tidal carbon dioxide (PCO(2)) was higher in the PTSD hyperarousal group than in the no-PTSD group during 3 min of quiet sitting, indicating no difference in baseline hyperventilation. There was no significant effect of the intervention on PTSD hyperarousal symptoms or hyperventilation compared to wait list, but treatment did lower respiratory rate. CONCLUSION: This intervention did not reduce PTSD hyperarousal symptoms, perhaps due to differences between underlying mechanisms of PTSD hyperarousal and panic disorder or to differences between veteran and civilian populations. (PsycINFO Database Record (c) 2019 APA, all rights reserved).