Approximate Entropy of Respiratory Patterns in Panic Disorder

Caldirola, Daniela; Bellodi, Laura; Caumo, Andrea; Migliarese, Giovanni; Perna, Giampaolo

doi:10.1176/appi.ajp.161.1.79

Cited by 110 publications

(65 citation statements)

References 52 publications

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“…This natural physiological reaction may result in a similar disruption of partial pressure of carbon dioxide in both PD patients and control subjects during the initial recovery from the challenge. A higher variability in respiratory measures in PD patients, compared with control subjects, was also found by Caldirola et al 16 in an elegant study focusing on complexity of respiratory dynamics. These authors investigated the breath-by-breath complexity of respiration dynamics in PD patients during the resting condition.…”

Section: Discussionsupporting

confidence: 71%

Objective and Subjective Measures in Recovery from a 35% Carbon Dioxide Challenge

2008

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Objectives: Because hyperventilation, dyspnea, and a feeling of choking are often core features of a panic attack, respiration has been one of the most widely studied physiological parameters in panic disorder (PD) patients. A respiratory subgroup of PD, with distinct etiological pathways, has also been suggested. Investigation of the recovery phase following a respiratory challenge may be a reliable way to establish respiratory impairment in PD patients. The objective of the present study was to investigate the recovery phase from a 35% carbon dioxide challenge in PD patients and in healthy controls, and to test the hypothesis of a different respiratory pattern in patients, compared to control subjects. Methods: Eleven nonmedicated PD patients with or without agoraphobia, 11 medicated PD patients, and 11 control subjects took part in a 35% carbon dioxide and 65% oxygen inhalation challenge. Respiratory rate, partial pressure of carbon dioxide, heart rate, and blood pressure were recorded during the baseline phase (10 minutes) and the recovery phase (10 minutes). Visual Analogue Scale of Anxiety and Panic Symptom List scores were collected pre- and post-challenge. Results: Nonmedicated patients had increased variability in respiratory rate and partial pressure of carbon dioxide during recovery, compared with control subjects and medicated PD patients. Also, PD patients tended to have higher heart rates and to need more time to recover from the challenge than control subjects. Conclusions: Results suggest that PD patients have less effective homeostatic control after their physiological equilibrium has been disrupted by a respiratory stressor.

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Section: Discussionsupporting

confidence: 71%

Objective and Subjective Measures in Recovery from a 35% Carbon Dioxide Challenge

2008

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“…Enhanced capabilities to quantify differences among such series would be extremely valuable, since these time series reflect essential biological information. ApEn has been used to quantify the differences in apparent regularity between the heart rate interval time series of aborted sudden infant death syndrome and healthy infants [7], to extract features from electroencephalogram and respiratory recordings of a patient during Cheyne-Stokes respiration [32] and to study the connection between panic disorder and respiration dynamics [33]. Moreover, it has been used to investigate changes in respiratory movement during stages of sleep and to associate such alterations with brain function [34].…”

Section: Discussionmentioning

confidence: 99%

Oxygen saturation regularity analysis in the diagnosis of obstructive sleep apnea

Campo

Hornero

Zamarrón

et al. 2006

Artificial Intelligence in Medicine

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“…Klein's suffocation alarm hypothesis (Klein, 1993), for example, suggests that both panic attacks and the consistent respiratory abnormalities seen in panic patients may be due to hypersensitive, medullary carbon dioxide (CO 2 ) detectors. Among the cross sectional findings supporting this hypothesis are increased variability in tidal volume and minute ventilation (Abelson et al, 2001;Gorman et al, 1988;Caldirola et al, 2004), exaggerated lactate responses to room air hyperventilation (Dager et al, 1995), and hypersensivity to inhaled carbon dioxide (Gorman et al, 2004) in PD patients compared to controls. Regarding baseline levels of pCO2 studies are more mixed, with some showing lower levels in PD patients than healthy controls during baseline periods (Papp et al, 1997;Hegel and Ferguson, 1997) and others no differences in comparison to control or other anxious groups (e.g.…”

Section: Targeting Respiration In Panic Disorder Treatmentmentioning

confidence: 99%

Feedback of end-tidal pCO2 as a therapeutic approach for panic disorder

Meuret¹,

Wilhelm²,

Ritz³

et al. 2008

Journal of Psychiatric Research

145

124

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Background-Given growing evidence that respiratory dysregulation is a central feature of panic disorder (PD) interventions for panic that specifically target respiratory functions could prove clinically useful and scientifically informative. We tested the effectiveness of a new, brief, capnometry-assisted breathing therapy (BRT) on clinical and respiratory measures in PD.Methods-Thirty-seven participants with PD with or without agoraphobia were randomly assigned to BRT or to a delayed-treatment control group. Clinical status, respiration rate, and end-tidal pCO 2 were assessed at baseline, posttreatment, 2-month and 12-month follow-up. Respiratory measures were also assessed during homework exercises using a portable capnometer as a feedback device.Results-Significant improvements (in PD severity, agoraphobic avoidance, anxiety sensitivity, disability, and respiratory measures) were seen in treated but not untreated patients, with moderate to large effect sizes. Improvements were maintained at follow-up. Treatment compliance was high for session attendance and homework exercises; dropouts were few.Conclusions-The data provide preliminary evidence that raising end-tidal pCO 2 by means of capnometry feedback is therapeutically beneficial for panic patients. Replication and extension will be needed to verify this new treatment's efficacy and determine its mechanisms.

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Approximate Entropy of Respiratory Patterns in Panic Disorder

Abstract: Patients with panic disorder showed greater entropy in baseline respiratory patterns, indicating higher levels of irregularity and complexity in their respiratory function. Greater respiratory entropy could be a factor in vulnerability to panic attacks.

Cited by 110 publications

References 52 publications

Objective and Subjective Measures in Recovery from a 35% Carbon Dioxide Challenge

Objective and Subjective Measures in Recovery from a 35% Carbon Dioxide Challenge

Oxygen saturation regularity analysis in the diagnosis of obstructive sleep apnea

Feedback of end-tidal pCO2 as a therapeutic approach for panic disorder

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