Caffeine challenge and breath-holding duration in patients with panic disorder

Lack of specific association between panicogenic properties of caffeine and HPA-axis activation. A placebo-controlled study of caffeine challenge in patients with panic disorder

“…Extant studies propose that these mechanisms include patients' abnormalities in their respiratory functioning (Nardi et al, 2007;Masdrakis et al, 2008Masdrakis et al, , 2009Freire et al, 2010). More precisely, in line with Donald Klein's theory (Klein, 1993), previous studies of our group indicate that PD patients panicking after caffeine administration exhibit a pathological hypersensitivity to CO 2 accumulation already at baseline -as indicated by their significantly lower baseline breath-holding (BH) duration compared to non-panickers (Masdrakis et al, 2008(Masdrakis et al, , 2009). This is further exacerbated at post-challenge, as indicated by the significantly greater decreases of BH duration at post-challenge, compared to non-panickers (Masdrakis et al, 2009).…”

“…Caffeine challenge procedure: The caffeine-challenge procedure was identical to the one previously described by our team (Masdrakis et al, 2008(Masdrakis et al, , 2009). The procedure always started at about 0800 h. At arriving, patient's belongings that could increase her/ his sense of "control" (Sanderson et al, 1989) during the experimentation (books, chewing gums, water, mobile phone, etc.)…”

“…A "panic attack" was defined as the state in which all three of the following criteria were met (Masdrakis et al, 2008(Masdrakis et al, , 2009 (1) A Z30% increase in the intensity of Z4 DSM-IV-TR "panic attack" symptoms compared to baseline, as measured by a visual analog scale. (2) Abrupt onset, rapid escalation and peak within 10 min of these symptoms.…”

“…Previous reports have established caffeine as a panicogenic probe in PD (Boulenger et al, 1984;Charney et al, 1985;Lee et al, 1988;Klein et al, 1991;Nardi et al, 2006Nardi et al, , 2007Masdrakis et al, 2008Masdrakis et al, , 2009; see for a review: Vilarim et al, 2011). The main neurobiological mechanism underlying caffeine's psychostimulant properties is assumed to be the antagonism of central adenosine receptors (Boulenger et al, 1984;Alsene et al, 2003;Gajewska et al, 2013).…”

Efeito do broncodilatador no tempo de apneia voluntária máxima em pacientes com distúrbios ventilatórios obstrutivos

“…(10) Pulmonary function was evaluated with a MasterScreen Body spirometer (Jaeger, Würzburg, Germany), in accordance with the American Thoracic Society/European Respiratory Society guidelines (10,11) and previously published reference values. (12)(13)(14)(15)(16) In order to determine the BHT max at end-inspiratory volume (BHT max V EI ), we instructed the participants to inhale deeply three times (with a mouthpiece and a nose clip); at the end of the third maximal inspiratory maneuver, the participants were instructed to hold their breath for as long as they could. In order to determine the BHT max at end-expiratory volume (BHT max V EE ), we instructed the participants to inhale and exhale deeply (under the same conditions as those described above) three times and then hold their breath for as long as they could.…”