Respiratory physiology & neurobiology
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Respir Physiol Neurobiol · Feb 2014
An open-source software for automatic calculation of respiratory parameters based on esophageal pressure.
We have developed a software that automatically calculates respiratory effort indices, including intrinsic end expiratory pressure (PEEPi) and esophageal pressure-time product (PTPeso). ⋯ Our program provides a reliable method for the automatic calculation of PEEPi and respiratory effort indices, which may facilitate the use of these variables in clinical practice. The software is open source and can be improved with the development and validation of new respiratory parameters.
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Respir Physiol Neurobiol · Feb 2014
Cardio-ventilatory responses to poikilocapnic hypoxia and hypercapnia in trained breath-hold divers.
Trained breath-hold divers (BHDs) are exposed to repeated bouts of intermittent hypoxia and hypercapnia during prolonged breath-holding. It has thus been hypothesized that their specific training may develop enhanced chemo-responsiveness to hypoxia associated with reduced ventilatory response to hypercapnia. Hypercapnic ventilatory responses (HCVR) and hypoxic ventilatory responses at rest (HVRr) and exercise (HVRe) were assessed in BHDs (n=7) and a control group of non-divers (NDs=7). ⋯ However, both HVRr (+68%) and HVRe (+31%) were increased in BHDs. CO and HR reached lower values in BHDs than NDs during the hypoxic exercise test. These results suggest that the exposure to repeated bouts of hypoxia/hypercapnia frequently experienced by trained breath-hold divers only enhances their chemo-responsiveness to poikilocapnic hypoxia, without altering HCVR.
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Respir Physiol Neurobiol · Feb 2014
Airflow obstruction and left ventricular filling pressure in suspected chronic obstructive pulmonary disease.
Left ventricular (LV) filling impairment is present in patients with chronic obstructive pulmonary disease (COPD). Airflow obstruction is related to reduced LV end-diastolic volume, stroke volume, and cardiac output. The ratio of peak early diastolic filling velocity of the mitral inflow to peak early diastolic velocity of the mitral annulus (E/e'), an echocardiographic parameter, can be applied as a surrogate marker of LV filling pressures. ⋯ Multivariate linear regression analysis showed that the FEV1/FVC ratio (β=0.01; 95% confidence interval, 0.001-0.019; p=0.036) independently predicted the log transformed E/e' ratio. An increase of FEV1/FVC ratio (in percentage) by 1 unit was associated with an increase of the E/e' ratio multiplied by 1.01. Airflow obstruction inversely predicts LV filling pressure in suspected COPD cases.
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Respir Physiol Neurobiol · Feb 2014
Dyspnea as a side effect of subthalamic nucleus deep brain stimulation for Parkinson's disease.
Bilateral subthalamic nucleus deep brain stimulation for Parkinson's disease improves limb function. Unpublished observations from our clinic noted that some subthalamic nucleus deep brain stimulation patients complain of post-operative dyspnea. Therefore, we designed a prospective, longitudinal study to characterize this in greater depth. ⋯ George's Hospital Respiratory Questionnaire impact subscale, the Medical Research Council Dyspnoea Scale, and the Dyspnoea-12 Questionnaire. There was no correlation between limb function ratings, stimulation parameters, or precise electrode position and dyspnea severity. We have shown, for the first time, that dyspnea can be a side effect of subthalamic nucleus deep brain stimulation, and that this dyspnea may be highly disabling.
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Respir Physiol Neurobiol · Feb 2014
Randomized Controlled TrialEffect of rostral fluid shift on pharyngeal resistance in men with and without obstructive sleep apnea.
Obstructive sleep apnea (OSA) relates to overnight rostral fluid shift, possibly because fluid accumulation around the pharynx increases pharyngeal resistance (Rph). We hypothesised that Rph will increase more in men with than without OSA in response to rostral fluid redistribution. ⋯ OSA patients have increased susceptibility to pharyngeal obstruction in response to rostral fluid redistribution, which could predispose to pharyngeal collapse during sleep.