Prolonged Expiration Research Articles

MANAGEMENT OF CRISES DURING ANESTHESIA AND SURGERY. PART III: Bronchospasm & Laryngospasm

Bronchospasm usually manifests during anaesthesia as an expiratory wheeze, prolonged expiration and/or increased inflation pressures during intermittent positive pressure ventilation (IPPV). Wheeze may be audible either with or without auscultation, but can only be present if there is gas flow in the patient’s airways. Thus, in cases of severe bronchospasm, the chest may be silent on auscultation and the diagnosis may rest on correct assessment of increased inflation pressures 1 . Other signs include; low oxygen saturation, change in capnogram, hypoventilation and hypotension 2 .

Chest physical therapy is effective in reducing the clinical score in bronchiolitis: randomized controlled trial

To evaluate the effectiveness of chest physical therapy (CP) in reducing the clinical score in infants with acute viral bronchiolitis (AVB). Randomized controlled trial of 30 previously healthy infants (mean age 4.08 SD 3.0 months) with AVB and positive for respiratory syncytial virus (RSV), evaluated at three moments: at admission, then at 48 and 72 hours after admission. The procedures were conducted by blinded assessors to each of three groups: G1 - new Chest Physical therapy- nCPT (Prolonged slow expiration - PSE and Clearance rhinopharyngeal retrograde - CRR), G2 - conventional Chest Physical therapy- cCPT (modified postural drainage, expiratory compression, vibration and percussion) and G3 - aspiration of the upper airways. The outcomes of interest were the Wang's clinical score (CS) and its components: Retractions (RE), Respiratory Rate (RR), Wheezing (WH) and General Conditions (GC). The CS on admission was reduced in G1 (7.0-4.0) and G2 (7.5-5.5) but was unchanged in G3 (7.5-7.0). We observed a change 48 hours after hospitalization in G1 (5.5-3.0) and G2 (4.0-2.0) and in 72 hours, there was a change in G1 (2.0-1.0). The CP was effective in reducing the CS in infants with AVB compared with upper airway suction only. After 48 hours of admission, both techniques were effective and nCPT techniques were also effective in the 72 hours after hospitalization compared with cCPT techniques.

Non-invasive Estimation of Cardiac Output in Mechanically Ventilated Patients: A Prolonged Expiration Method

A non-invasive method for the estimation of cardiac output in mechanically ventilated patients is described. The method is based on prolonged expiration, and relies on measurement of gas concentrations and flow rate. A pneumatic system, with an ad hoc designed orifice resistance, has been made and experimentally characterized to adapt the breathing circuit to this application. Cardiac output is calculated using two algorithms and the results are compared with the ones obtained by thermodilution. To this purpose, we prospectively enrolled twenty mechanically ventilated patients, who had undergone cardiac surgery, and both algorithms show good correlation with thermodilution (R > 0.8). The application of the first algorithm gave mean cardiac output values slightly lower than those obtained by thermodilution (-6%), while the application of the second algorithm gave higher values (+30%). Difference standard deviations between paired measurements is 0.72 L min(-1) for the first algorithm and 1.07 L min(-1) for the second one. Standard deviation obtained by the application of the first algorithm is slightly lower than those relative to other minimally invasive techniques. Through prolonged expiration, and standardization and automation of the procedure on mechanically ventilated patients, the proposed system allows to obtain a non-invasive estimation of cardiac output.

大鼠背侧脑桥及腹侧脑桥神经元NMDA受体在黑伯反射中的作用

黑伯反射又称为肺牵张感受器反射，是肺牵张感受器兴奋所导致的呼气延长与吸气缩短反应。电刺激迷走神经中枢端可以模拟该反射。我们前期研究发现，在腹侧脑桥，NMDA受体介导的递质传递可以对黑伯反射产生调节作用。本研究在前期研究基础上，以大鼠为实验对象，通过电刺激其迷走神经中枢端诱导出黑伯反射，分别向背侧脑桥及腹侧脑桥内微量注射NMDA受体阻断剂D-2-氨基-5-磷酸基戊酸(D-AP5)，观察药物对黑伯反射的调节作用。结果表明，向背侧脑桥注射D-AP5后，黑伯反射的呼吸抑制效应明显增强，向腹侧脑桥注射D-AP5，黑伯反射的呼吸抑制效应明显削弱。NMDA受体介导的递质传递在背侧脑桥及腹侧脑桥对黑伯反射发挥方向相反的调节作用。 Vagal stimulation evokes Hering-Breuer Reflex (HBR), which is characterized by inspiratory inhibition and expiratory prolongation. In this work, the role of NMDA receptors located in dorsolateral-pons and ventrolateral-pons were studied and compared by comparing the strength of this reflex before and after microinjecting D-AP5. Experi- ments were performed on urethane anesthetized adult rats. The HBR was simulated by electrical stimulation of the central end of cervical vagus nerve. We found that the HBR was strengthened after microinjection D-AP5 into dorsolateral-pons, while weakened after microinjection in ventrolateral-pons. This work shows that NMDA receptor mediated neurotransmissions both in dorsolateral-pons and ventrolateral-pons exert opposite effects on HBR.

Prolonged Slow Expiration Technique in Infants: Effects on Tidal Volume, Peak Expiratory Flow, and Expiratory Reserve Volume

Prolonged slow expiration (PSE) is a physiotherapy technique often applied in infants to reduce pulmonary obstruction and clear secretions, but there have been few studies of PSE's effects on the respiratory system. To describe PSE's effects on respiratory mechanics in infants. We conducted a cross-sectional study with 18 infants who had histories of recurrent wheezing. The infants were sedated for lung-function testing, which was followed by PSE. The PSE consisted of 3 sequences of prolonged manual thoraco-abdominal compressions during the expiratory phase. We measured peak expiratory flow (PEF), tidal volume (V(T)), and the frequency of sighs during and immediately after PSE. We described the exhaled volume during PSE as a fraction of expiratory reserve volume (%ERV). We quantified ERV with the raised-volume rapid-thoracic-compression technique. The cohort's mean age was 32.2 weeks, and they had an average of 4.8 previous wheezing episodes. During PSE there was significant V(T) reduction (80 ± 17 mL vs 49 ± 11 mL, P < .001), no significant change in PEF (149 ± 32 mL/s vs 150 ± 32 mL/s, P = .54), and more frequent sighs (40% vs 5%, P = .03), compared to immediately after PSE. The exhaled volume increased in each PSE sequence (32 ± 18% of ERV, 41 ± 24% of ERV, and 53 ± 20% of ERV, P = .03). It was possible to confirm and quantify that PSE deflates the lung to ERV. PSE caused no changes in PEF, induced sigh breaths, and decreased V(T), which is probably the main mechanical feature for mucus clearance.

Evaluation of a new fiber-grating vision sensor for assessing pulmonary functions in healthy and COPD subjects

Spirometry is practically the only tool to evaluate pulmonary functions. Other automatic systems comparable to spirometry are expected. A fiber-grating (FG) vision sensor is a non-contact respiratory monitoring system to detect changes in volumes by measuring the movement of laser spots on the body surface. We examined the contributions of the FG sensor to evaluating pulmonary functions. The FG sensor showed a linear correlation with spirometry in tidal volumes (TV) obtained from five controls (R = 0.98, P < 0.0001). We also showed agreement of TV between the two devices using Bland–Altman analysis. TV measured by the FG sensor were reproducible and applicable to distinct subjects. To detect airway obstruction, we performed forced expiration in controls (n = 16) and chronic obstructive pulmonary disease (COPD) patients (n = 18) with the FG sensor and spirometry. Forced expiratory volume in 1 s (FEV1) and FEV1/forced vital capacity in COPD patients were lower than those in controls by the FG sensor. In addition, prolonged expiration in natural breathing by the FG sensor was related to airflow limitation by spirometry. The FG sensor was helpful to measure volume changes and to evaluate pulmonary functions in controls and patients with COPD. Its upcoming clinical applications are promising for simplicity and feasibility.

Effects of prolonged expiration breathing on cardiopulmonary responses during incremental exercise

This study was designed to clarify the effects of breathing with prolonged expiration on cardiopulmonary responses and autonomic nervous activity during incremental exercise. Eleven healthy men were randomly assigned to breathing mode: a prolonged expiration breathing with a 2-s inspired time and 4-s expired time and a spontaneous breathing without any constraints. Oxygen uptake (V(O2)), ventilation efficiency (V(E)/V(CO2)) and rate pressure product were measured. Low- (LF) and high-frequency (HF) components of blood pressure and heart rate variability were analyzed to assess sympathetic and parasympathetic nervous activities, respectively. V(E)/V(CO2), rate pressure product and LF were significantly lower, and [Formula: see text] and HF were significantly higher during exercise with prolonged expiration than with spontaneous breathing. Striking effects of prolonged expiration breathing included the improvement of ventilation efficiency, the suppression of sympathetic nervous activity and the activation of parasympathetic one during incremental exercise. Furthermore, prolonged expiration breathing may have suppressed the exercise-induced increase in myocardial V(O2).

Evaluation of an Alternative Chest Physiotherapy Method in Infants With Respiratory Syncytial Virus Bronchiolitis

We proposed a new chest physiotherapy (CPT) secretion clearance method to treat respiratory syncytial virus bronchiolitis in infants. Our new CPT method consists of 15 prolonged slow expirations, then 5 provoked cough maneuvers. We randomized 20 infants (mean age 4.2 months) into 2 groups: 8 patients received 27 sessions of nebulization of hypertonic saline; 12 patients received 31 sessions of nebulization of hypertonic saline followed by our new CPT method. We used the Wang clinical severity scoring system (which assesses wheezing, respiratory rate, retractions, and general condition) and measured S(pO(2)) and heart rate before each CPT session (T0), immediately after the 30-min session (T30), and 120 min after the session (T150). Within the groups: in the first group, Wang score was significantly lower at T150 than at T0: 4.6 vs 5.0 (P = .008). In the new-method-CPT group, Wang score was significantly lower at T30 (3.6 vs 4.3, P = .001) and at T150 (3.7 vs 4.3, P = .002). Wheezing score was significantly lower at T150 than at T0 (1.1 vs 1.2, P = .02) in the first group, and in the new-method-CPT group at T30 than at T0 (0.8 vs 1.3, P = .001) and at T150 than at T0 (0.9 vs 1.3, P = .001). Between the groups: at T30 the improvement was significantly better in the new-method-CPT group for overall Wang score (P = .02), retractions (P = .05), respiratory rate (P = .001), and heart rate (P < .001). At T150 the Wang score was not significantly different between the groups. At T30 (versus T0) the difference in percent gain between the groups was significant for Wang score (P = .004), wheezing (P = .001), and heart rate (P = .02). Over 5-hospital days, the daily baseline (T0) Wang score decreased significantly in the new-method-CPT group (P = .002), whereas it did not in the first group. There were no adverse events. Average hospital stay was not significantly different between the groups. Our new CPT method showed short-term benefits to some respiratory symptoms of bronchial obstruction in infants with acute respiratory syncytial virus bronchiolitis.

Bringing light to the sirens of night: laryngoscopy in catathrenia during sleep: Figure 1–

To the Editors: Catathrenia is a rare sleep disorder characterised by groaning and prolonged expiration confined to sleep alternating with normal breathing that may occur at all sleep stages. After its first description in 1983 1, catathrenia was recently introduced into the International Classification of Sleep Disorders 2. Although the exact pathogenesis remains unknown, catathrenia has been considered a parasomnia. Important differential diagnoses include moaning during epileptic seizures, central sleep apnoea, sleep-related laryngospasm, expiratory snoring and stridor. Most patients complain about social distress in their partnership, and only a minority suffers from excessive daytime sleepiness (EDS). Continuous positive airway pressure (CPAP) treatment has shown to be effective in some patients 3. Several postulated theories exist on the underlying mechanism. Ortega-Albas et al. 4 assumed the underlying mechanism was …

EFFECT OF RESPIRATION ON PULSE WAVE VELOCITY MEASUREMENTS IN THE ARM: PP.8.314

Introduction: Pulse Wave Velocity (PWV) in a vascular bed is determined significantly by the distending blood pressure (BP). Respiration influences systemic BP. Current guidelines for standardised measurement of PWV advise that recordings should be taken over a full respiratory cycle. No modern studies have quantified the degree to which respiration affects PWV measurements. We sought to assess the degree to which PWV in the arm will be affected by inspiration and expiration. Methods: Under standardised conditions PWV measurements were carried out in 10 volunteers during normal respiration. Thereafter PWV was measured during prolonged and help inspiration. Finally PWV was measured during prolonged and held expiration. Measurements were made in the carotid-radial segment (CRPWV) using applanation tonometry (SphygmoCor) and in the brachio-radial (BRPWV) segment using a piezoelectric system. Results: 10 volunteers completed the study, male = 6, mean age 31.2 years. None were on vasoactive medications. Mean CRPWV during normal respiration was 8.1 ± 0.6 m/sec. Mean BRPWV during normal respiration was 8.6 ± 1.4 m/sec. On the inspiration only studies a significant decrease was seen in CRPWV values (8.1 ± 0.6 m/sec vs 7.2 ± 0.7 p < 0.001, mean percentage change -11.2%) and BRPWV (8.6 ± 1.4 m/sec vs 7.8 ± 1.4 m/sec p = 0.005, mean percentage change -9.3%). During expiration CRPWV values increased from 8.1 ± 0.6 m/sec to 8.9 ± 0.8 m/sec (p = 0.002) with a mean percentage change from baseline was + 9.7%. BRPWV values also increased on the expiration only studies from 8.6 ± 1.4 m/sec to 9.3 ± 1.2 m/sec (p = 0.001), with a mean percentage change from baseline of + 7.8%. Conclusion: Deep respiration has significant effects on PWV measurements in the arm. This underlies the importance of measuring PWV in a relaxed patient over a full respiratory cycle.

Case 1: A long history of cough and dyspnea

A 10-year-old girl presented with a nine-year history of six to eight upper and lower respiratory tract infections annually, each with a duration of three to six weeks in spite of antibiotic treatment, accompanied with cough, dyspnea and occasional wheezing. She also reported these symptoms during physical exercise, independent of infections. Until now, three pneumonias and multiple bronchitic episodes had been verified. At five years of age, she was diagnosed with bronchial asthma. For two years, treatment consisted of intermittent courses of short-acting beta-agonists and inhaled corticosteroids, before she was switched to a daily combination treatment with long-acting beta-agonists and inhaled corticosteroids (budesonide-formoterol 160 μg/4.5 μg twice daily) plus montelukast 5 mg orally without any breakthrough. A sweat test performed at four years of age was normal, as was a skin prick test to common aeroallergens and measurements of exhaled nitric oxide. Previous lung function tests were reported as a bronchial obstruction with no or only partial bronchodilator response. On presentation, the child was afebrile with normal vital signs, including an oxygen saturation of 97% on room air. A physical examination was unremarkable except for a prolonged expiration on auscultation. A complete blood count was normal and the erythrocyte sedimentation rate was 18 mm/h (0 mm/h to 10 mm/h). Further workup revealed the diagnosis.

Les techniques de médecine physique peuvent-elles pallier la distension ?

The authors review the literature concerning the possibilities of modifying the mechanical characteristics of the respiratory system with breathing retraining and other chest physiotherapy intervention. Breathing retraining techniques with prolonged and active expiration induce increased work of breathing and do not help diaphragmatic function. Only pursed lips breathing seems to produce some mechanical advantages. The seated and forward position with fixed arms may reduce dyspnea but this does not appear to be caused by a decrease in operating lung volumes. By contrast, the dorsal decubitus position may reduce hyperinflation, giving some mechanical advantage to the diaphragm but does not reduce dyspnea and is not a position spontaneously adopted by patients. General muscular training may reduce ventilatory demand, and by reducing respiratory frequency lead to a decrease in the end expiratory lung volume; therefore inducing improvement in exercise tolerance.

PREVALENCE AND RISK FACTORS OF CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) IN DHAKA CITY BANGLADESH

This prospective, cross-sectional population based survey was carried out in the Respiratory wing, Department of Medicine, Bangabandhu Sheikh Mujib Medical University, Dhaka, Bangladesh to see the prevalence and risk factors of chronic obstructive pulmonary disease (COPD) among Dhaka City Population in Bangladesh. The total sample size was 900 at the age of 35 years or above. Spirometry was performed according to ATS criteria. Data related to smoking history, respiratory symptoms, co-morbidities, physical examination findings, spirometry values and other investigation reports were noted in the questionnaire. The mean age was 45.26±10.08 (Mean±SD); of them, male 76.9% and female 23.1%. Among them, smoker was 481 with a smoking duration of 10 pack year 27.8% and non smoker were 419. Spirometric screening yielded diagnosis of COPD in 11.4% (103/900). Using operational severity criteria adopted from Global Initiative for Obstructive Lung Disease (GOLD) mild, moderate, severe and very severe COPD were found in 42.7%, 27.2%, 20.4% and 9.7% respectively. The hall mark symptom of COPD exertional dyspnea was seen in 10.4%, non-specific symptoms like cough and sputum were found in 40% and 19% respectively. Physical sign like vesicular breath sound with prolonged expiration and ronchi were found in 6.1% and 4.1% respectively. In this study, age (Mean±SD in years) (57.34±11.74), Sex (Male: Female = 4:1), low BMI (Mean±SD) (21.56±3.83), Smoker 56(20.2%) and low Socio-economic condition 54(13.6%) found to be risk factor of COPD. Regression analysis revealed that age (p<0.001), sex (p<0.001), smoking duration (p<0.001) and low socioeconomic condition (p<0.05) as independent risk factors for COPD.

Patient-Ventilator Dyssynchrony: Clinical Significance and Implications for Practice

The cost of providing care to critically ill patients in the United States consumes roughly 15% of all health care dollars, or 1% of the gross national product.1 Contributing to this economic burden are patients admitted to the intensive care unit (ICU) who require mechanical ventilation and patients with complications from their dependence on this technology.2,3 In fact, 50% of ICU patients receive mechanical ventilation.4 Often, sedation is required to increase patients’ tolerance of the endotracheal tube, reduce anxiety, and facilitate sleep. In particular, sedation is used frequently to reduce patient-ventilator dyssynchrony (PVD).5–9 Sassoon and Foster10 define PVD as a mismatching between the patient’s breaths (neural) and ventilator-assisted breaths (phase asynchrony), as well as the inability of the ventilator’s flow delivery to match the patient’s flow demand (flow asynchrony). This definition suggests a faulty interaction between the patient and ventilator that is commonly managed by sedation and advanced ventilator modes and adjustments. The correction of PVD is complex and multifaceted given the current capabilities of traditional ventilators. An imperfect solution exists because the sensitivity and responsiveness of both the patient and the ventilator during the interaction is confounded by factors related to the patient and the ventilator. However, in light of the most serious complications (hypoxemia, barotrauma, prolonged mechanical ventilation, and discomfort) of PVD, and an imperfect solution for the resolution of PVD at the current time, nurses continue to face the challenge of preventing the consequences of PVD as well as complications due to oversedation or undersedation. In this article, we discuss the factors contributing to PVD; the manifestations, measurement, types, and causes of PVD; nursing implications; and future directions for improvement, with nursing research questions proposed for consideration.

The diagnostic value of history and physical examination for COPD in suspected or known cases: a systematic review.

According to current guidelines, spirometry should be performed in patients suspected of chronic obstructive pulmonary disease (COPD) by the results of history taking and physical examination. However, little is known about the diagnostic value of patient history and physical examination for COPD. To review the existing evidence on the diagnostic value of history taking and physical examination in recognizing COPD in patients suspected of COPD. A systematic literature search was performed in electronic medical databases. Studies were included after using defined inclusion and exclusion criteria and judged on their methodological quality by using the Quality Assessment of Diagnostic Accuracy Studies criteria. A formal meta-analysis was not performed because all studied items of history and physical examination were investigated in only in a maximum of three studies. Six studies were included. The history items dyspnoea, wheezing, previous consultation for wheezing or cough, self-reported COPD, age and smoking and the physical examination items wheezing, forced expiratory time, laryngeal height and prolonged expiration were found to have diagnostic value for COPD. These items were studied in maximally three studies and study population studies were heterogenic. The reference test for COPD in five of the six studies concerned obstructive lung disease in general and not COPD. There is insufficient evidence to assess the value of history taking and physical examination for diagnosing COPD.

Arousals in nocturnal groaning

Background and objective Nocturnal groaning (catathrenia) is a chronic sleep disorder classified as parasomnia with unclear effects on sleep and life quality. It is characterized by repeated episodes of monotonous vocalization in prolonged expiration (episodes of bradypnea) occurring mostly in REM sleep. We sought to assess its impact on sleep microstructure, i.e., the frequency of arousals relative to the groaning episodes. The frequency, duration and sleep-stage distribution of the groaning episodes were also studied. Methods Eight patients with nocturnal groaning (5 male, 3 female, age range 11–32 years, mean age 23 ± 7.1) were evaluated. All underwent standard neurologic examination and nocturnal videopolysomnography for two consecutive nights. The second night polysomnography data were used to evaluate sleep parameters. The groaning episodes (bradypneic events) were counted separately, not as clusters. Results Sleep macrostructure revealed no specific changes. The number of groaning episodes/bradypneic events during the night varied from 40 to 182 (total number 725). The duration of bradypnea was from 2 to 46 s (mean duration 12.5 s). Groaning episodes prevailed in REM sleep (76.5%). The rate for NREM 2 was 21.5%, and only sporadic episodes were noted in delta sleep (1.9%); 63.3% of the events were associated with arousals, and in 94% of them an arousal occurred before or together with the onset of bradypnea. The arousal index was increased in 5 patients (mean 20.4). Bruxism was present in 4 cases, in 1 patient appearing in close association with groaning episodes. Ronchopathy was noted in 4 cases. Conclusion Almost two-thirds of the groaning episodes were connected with arousals. Hypothetically, nocturnal groaning may well be a source of sleep disruption (mainly REM) in some cases. Because an arousal mostly preceded or coincided with groaning we believe that arousal mechanisms may be involved in the pathogenesis of nocturnal groaning.

Swallow Pattern Generator Reconfiguration of the Respiratory Neural Network

Abstract When the nasal and oral passages converge and a bolus enters the pharynx, it is critical that breathing and swallow motor patterns become integrated to allow safe passage of the bolus through the pharynx. Breathing patterns must be reconfigured to inhibit inspiration, and upper airway muscle activity must be recruited and reconfigured to close the glottis and laryngeal vestibule, invert the epiglottis, and ultimately protect the lower airways. Failure to close and protect the glottal opening to the lower airways, or loss of the integration and coordination of swallow and breathing, increases the risk of penetration or aspiration. A neural swallow central pattern generator (CPG) controls the pharyngeal swallow phase and is located in the medulla. We propose that this swallow CPG is functionally organized in a holarchical behavioral control assembly (BCA) and is recruited with pharyngeal swallow. The swallow BCA holon reconfigures the respiratory CPG to produce the stereotypical swallow breathing pattern, consisting of swallow apnea during swallowing followed by prolongation of expiration following swallow. The timing of swallow apnea and the duration of expiration is a function of the presence of the bolus in the pharynx, size of the bolus, bolus consistency, breath cycle, ventilatory state and disease.

Effectiveness of magnetic resonance angiography in the evaluation of lung perfusion in constrictive bronchiolitis obliterans

Childhood constrictive bronchiolitis obliterans (CBO) is characterized clinically by the persistence of obstructive respiratory symptoms following a prolonged episode of lower respiratory viral infection. The diagnosis depends on the clinical, radiological and laboratory findings. Perfusion defects on scintigraphy may predict the severity. This report describes a 2-year-old girl who presented with a 15-day history of respiratory distress despite treatment. Auscultation of the lungs revealed prolonged expiration and bilateral crepitant rales. CXR revealed bilateral paracardiac infiltration. She improved with a treatment regimen of bronchodilators, systemic steroids and antibiotherapy; however, rales were detected again 10 days after discharge. HRCT of the lung revealed an oligaemic-mosaic pattern, more prominent in the left lung. The diagnosis of CBO was made on the basis of these clinical and radiological findings. Perfusion was normal in the right lung but diffusely decreased in the left lung on perfusion scintigraphy by Tc99m-MAA. Magnetic resonance (MR) angiography source images of the lungs revealed significant but not diffuse perfusion defects in the left lung, in contrast to radionuclide scintigraphy. There were areas of low perfusion in the right lung, which were not evident in radionuclide scintigraphy. The use of source images of MRI angiography of the lungs may be more sensitive and specific for the detection of perfusion defects in patients with CBO and may assist in determining the prognosis.

Effect of CPAP therapy on catathrenia and OSA: a case report and review of the literature

Catathrenia is a rare, idiopathic, sleep-related respiratory condition characterized by irregular groans, which occur during prolonged expiration in sleep. The origins of catathrenia remain inexplicable, the long-term prognosis unexplained. Moreover, empirical treatment with neither pharmacological nor non-pharmacological approaches was satisfactory. We report a case of catathrenia with concurrent obstructive sleep apnea complicated with pulmonary hypertension and reviewed the literature. Treatment with nasal continuous positive airway pressure resulted in marked improvement of catathrenia, obstructive sleep apnea, daytime dyspnea, and pulmonary hypertension for our patient. We think that nasal continuous positive airway pressure can be an option for the treatment of this infrequent but sometimes very disturbing sleep disorder.

Upper airway pressure-flow relationships and pharyngeal constrictor EMG activity during prolonged expiration in awake goats

We undertook the present investigation to establish whether narrowing/closure of the upper airway occurs during spontaneous and provoked respiratory rhythm disturbances and whether pharyngeal constrictor muscle recruitment occurs coincident with upper airway occlusion during prolonged expiratory periods. Upper airway pressure-flow relationships and middle pharyngeal constrictor (mPC) EMG activities were recorded in 11 adult female goats during spontaneous and provoked prolongations in expiratory time (Te). A total of 213 spontaneous prolongations of expiration were recorded. Additionally, 169 prolonged expiratory events preceded by an augmented breath were included in the analyses. In separate trials on different days, Te was prolonged by systemic administration of dopamine, by raising the inspired fraction of O(2) from 0.10 to 1.00 during poikilocapnic conditions or by systemic administration of clonidine. Continuous tonic activation of the mPC EMG was observed during each prolonged Te period regardless of the duration or initiating cause. However, significant increases in subglottic tracheal pressure, with expiratory airflow braking indicative of upper airway narrowing or closure, was only observed during spontaneous events without a preceding augmented breath and during clonidine-induced events. Tonic mPC activation proved an unreliable indicator of airway occlusion. Furthermore, mPC muscle activation alone is not sufficient to induce pharyngeal occlusion during prolonged expiration. Our data suggest that airway closure is not a common occurrence during provoked respiratory disturbances in awake goats. We propose that airway closure, when present during prolonged Te, is more likely dependent on activation of laryngeal adductor muscles with glottic braking independent of pharyngeal narrowing.