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At least 1,315 records · Page 73Linked to original sources
PubMed2002

Resting respiration in dysphagic patients following acute stroke.

The aim of this study was to examine respiration characteristics at rest in healthy volunteers and patients with poststroke dysphagia, using a simple notebook computer-based system. Eighteen patients (age range=51-82 years) with dysphagia poststroke and 50 healthy volunteers (age range=20-78 years) were recruited. The patient group had a wide range of stroke severity as assessed using the Scandinavian Stroke Score (SSS 6-51) and Barthel Index (BI 2-20). Length of breathing cycle, rate, and a measure of the variability of the cycle length were examined. The patient group had a shorter mean cycle length (2.93 s compared with 3.91 s, p < 0.01) and hence faster respiration rate (0.35 Hz compared with 0.26 Hz, p < 0.01). The control group showed greater variability in the cycle length (10.78% compared with 6.56%, p = 0.01). There was no correlation between the SSS and BI and resting respiration variables. This suggests that it is not stroke severity alone that affects breathing. The differences observed in resting respiratory rate suggest that respiratory monitoring as a useful adjunct to the clinical bedside assessment warrants further investigation.

Aged↗
PubMed2004

Normal brain mitochondrial respiration in adult mice lacking cellular prion protein.

Cellular prion protein (PrP(c)) gene (Prnp) null mice (Prnp0/0) show higher sensitivity to seizures, enhanced brain oxidative stress, and their neurons exhibit higher excitability "in vitro". Mitochondrial respiration is a useful parameter for the determination of cellular metabolic rate and it is a major source of reactive oxygen species (ROS). In the present study, we investigated the mitochondrial function of different brain areas of Prnp0/0 adult mice and then compared this to normal control animals. Baseline mitochondrial respiration (stages 3 and 4), respiratory control ratio (RCR) and membrane potential were evaluated in the neocortex, entorhinal cortex, hippocampus, and cerebellum. No differences in these parameters were detected between Prnp0/0 and wild-type mice. Thus, we concluded that baseline mitochondrial respiration might not be directly related with the higher oxidative stress previously observed in brains from Prnp0/0 mice.

Animals↗
PubMed2000

[Central sleep apnea syndrome and Cheyne-Stokes respiration].

This overview discusses pathogenesis, clinical presentation, prognostic implications and therapy of central sleep apnea with special reference to Cheyne-Stokes-Respiration or periodic breathing. In contrast to obstructive sleep apnea due to upper airway collapse during sleep, central sleep apnea (CSA) is mainly due to an instability of the breathing control system. Causes of central sleep apnea include alveolar hypoventilation disorders, heart failure, neurologic and autonomic disorders and idiopathic forms of CSA. Patients with idiopathic CSA often complain of insomnia and awakening during sleep but may also suffer from daytime sleepiness. Cheyne-Stokes-Respiration or peridic breathing is often associated with heart failure and neurological disorders especially those involving the brainstem. In heart failure periodic breathing has enormous prognostic implications. Treatment options for central sleep apnea are oxygen supplementation, medical therapy (i.e. acetazolamide) and CPAP. For patients with central sleep apnoea associated with alveolar hypoventilation nasal ventilation is treatment of choice. Newer nasal ventilation techniques (BiPAP, AutoSetCS) are under investigation for heart failure patients with Cheyne-Stokes-Respiration.

Cheyne-Stokes Respiration↗
PubMed1977

Effect of different respirator adjustments on central haemodynamics in open-heart surgery patients.

Changes in cardiac index (CI) mean pulmonary artery pressure (PAP), mean pulmonary capillary wedge pressure (PCWP), central venous pressure (CVP), and pulmonary artery vascular resistance (PVR), associated with spontaneous respiration (SR) and two different types of intermittent positive pressure ventilation (IPPPV and IPNPV) were studied in a total of 17 patients undergoing aortic valve replacement or myocardial revascularization. Swan-Ganz thermodilution pulmonary artery cardiac output catheters were used and the aim was to determine: whether postoperative cardiac output may paradoxically be greater during IPPPV than during IPNPV or SR; whether the use of "negative" pressure in the expiratory phase during controlled ventilation may be responsible for bringing about the central haemodynamic conditions prevailing during spontaneous respiration; and whether, in weaning from postoperative IPPPV to SR, there is a risk of pulmonary congestion as a consequence of possible autotransfusion. IPPPV connected with anaesthesia induction caused a highly significant deterioration central haemodynamics. The use of positive end-expiratory pressure (PEEP) is not to be recommended for such patients at this stage. On the first postoperative day, the mean CI was lower during IPPPV than during IPNPV (P less than 0.1) or during SR (P less than 0.05). The changes observed in CI, were, however, so slight that the authors consider the routine use of PEEP to be beneficial during controlled ventilation following major open-heart surgery. In some patients, the CI was paradoxically higher during IPPPV than during IPNPV or SR. The mean CI was nearly the same during IPNPV (3.32) as during SR (3.38). However, PAP, PCWP and PVR values were significantly higher during SR than during IPNPV. Thus, according to this study, the use of "negative" end-expiratory pressure during controlled ventilation did not in these patients produce central pressure conditions corresponding to spontaneous respiration. The present study supports the finding that in weaning from controlled ventilation with PEEP to SR there is a danger of pulmonary congestion. This could be predicted by measurement of pulmonary wedge pressure, but not by measurement of central venous pressure.

Adult↗
PubMed1986

Upper airway occlusion during sleep in patients with Cheyne-Stokes respiration.

Sleep-induced periodic breathing has been suggested to lead to the development of occlusive apneas in patients with sleep apnea syndrome. If this were true, patients with Cheyne-Stokes respiration should also develop upper airway occlusion during sleep. To study this hypothesis, 6 nonobese patients with Cheyne-Stokes respiration lacking evidence for sleep apnea syndrome and anatomic upper airway abnormalities underwent polysomnography during daytime naps. A total of 463 apneas were analyzed in the 6 patients studied. In 1 patient, no evidence of upper airway occlusion was observed. In the remaining 5 patients, a varying frequency of upper airway occlusion resembling the pattern of mixed apnea was seen in 3 to 97% of the total apneas analyzed. The mean number (+/- 1 SD) of occluded inspiratory efforts per mixed apnea in these 5 patients was 1.69 +/- 0.59. These results show that patients with Cheyne-Stokes respiration may develop upper airway occlusion during sleep and are consistent with the contention that sleep-induced periodic breathing in patients with sleep apnea syndrome is primary to the development of occlusive apneas.

Carbon Dioxide↗
PubMed2001

Noninvasive pressure preset ventilation for the treatment of Cheyne-Stokes respiration during sleep.

Cheyne-Stokes respiration (CSR) during sleep is common in patients with congestive heart failure (CHF). This pattern of breathing fragments sleep, leading to daytime symptoms of sleepiness and fatigue. It was hypothesized that by controlling CSR with noninvasive pressure preset ventilation (NPPV), there would be a decrease in sleep fragmentation and an improvement in sleep quality. Nine patients (eight males, one female; mean +/- SD 65 +/- 11 yrs) with symptomatic CSR diagnosed on overnight polysomnography (apnoea/hypopnoea index (AHI) 49 +/- 10 x h(-1), minimum arterial oxygen saturation (Sa,O2, 77 +/- 7%) and CHF (left ventricular ejection fraction 25 +/- 8%) were studied. After a period of acclimatization to NPPV (variable positive airway pressure (VPAP) II ST, Sydney, NSW, Australia and bilevel positive airway pressure (BiPAP), Murraysville, PA, USA), sleep studies were repeated on therapy. NPPV almost completely abolished CSR in all patients with a reduction in AHI from 49 +/- 10 to 6 +/- 5 x h(-1) (p<0.001). Residual respiratory events were primarily due to upper airway obstruction at sleep on-set. Arousal index was markedly decreased from 42 +/- 6 to 17 +/- 7 x h(-1) (p <0.001). Sleep architecture showed a trend toward improvement with a reduction in stage 1 and 2 (79 +/- 7% during the diagnostic night versus 72 +/- 10% during NPPV, (p=0.057)), whilst sleep efficiency, slow-wave sleep (SWS), and rapid eye movement (REM) were not altered. Controlling Cheyne-Stokes respiration with noninvasive pressure preset ventilation resulted in reduced arousal and improved sleep quality in the patients with congestive heart failure. Noninvasive pressure preset ventilation should be considered a potential therapy for Cheyne-Stokes respiration in congestive heart failure in those patients who do not respond or fail to tolerate nasal continuous positive airway pressure therapy.

Aged↗
PubMedDate not supplied

Nonivasive assessment by capacitance respirometry of respiration before and after extubation.

Respiration before and after extubation was studied in postoperative patients following weaning from respirator support. Changes in tidal and minute volume and respiratory flow rates were determined by capacitance respirometry, a noninvasive method of monitoring respiration. The presence of an endotracheal tube of 7.5 to 8.5 mm ID had no significant effect on ventilation, respiratory flow rates, or intrapulmonary shunting. Laboratory and clinical evidence showed that in postoperative patients, an endotracheal tube of 8 mm ID substitutes a relatively low, predictable resistance for a potentially excessive and variable upper airway resistance.

Cardiac Surgical Procedures↗
PubMed1992

Effects of corticotropin-releasing hormone on the postoperative course of elderly patients under long-term artificial respiration.

In both human and animal studies a stimulatory effect of corticotropin-releasing hormone (CRH) on respiration and on cognitive parameters has been demonstrated. Our own studies employing human CRH (hCRH) iv in healthy volunteers and different groups of patients have shown hCRH to be a safe drug. We prospectively studied the clinical effects of a standardized dose of 100 micrograms hCRH iv in 12 elderly patients following major abdominal surgery who remained comatose and were under prolonged respirator therapy over a mean period of 37 days. Cardio-respiratory parameters, blood gas values, plasma cortisol and catecholamines were evaluated before and 30 min following hCRH injection. Furthermore, vigilance was tested using a score system. Ventilation was markedly enhanced following hCRH injection while the cardiovascular parameters were only moderately affected. Vigilance was augmented in all subjects and improved impressively in five patients. The changes were of great benefit for the patients treated and supported their respirator weaning procedures and mobilization training.

Abdomen↗
PubMed2003

Cheyne-Stokes respiration in patients with congestive heart failure.

Cheyne-Stokes Respiration (CSR) is a breathing pattern characterised by rhythmic oscillation of tidal volume with regularly recurring periods of hyperpnoea, hypopnoea and apnoea. CSR is no longer solely regarded as a symptom of severe congestive heart failure (CHF), but has been recognised as an independent risk factor for worsening heart failure and reduced survival in patients with CHF. CSR is associated with frequent awakening that fragment sleep and with concomitant sympathetic activation both of which may worsen CHF. Cheyne-Stokes Respiration is very common in patients with severe CHF and its prevalence may have been underestimated in the past due to technical limitations that precluded respiratory monitoring outside sleep laboratories. Since treatment of CSR appears to be beneficial and safe, patients at risk should be promptly diagnosed and treated. Treatment of CSR has been demonstrated to improve left ventricular ejection fraction and potentially prolongs survival in patients with severe CHF. This article briefly summarises the current knowledge of the patho-physiology, prevalence and therapy of Cheyne-Stokes respiration.

Age Distribution↗
PubMedDate not supplied

The effect of heart transplantation on Cheyne-Stokes respiration associated with congestive heart failure.

Cheyne-Stokes respiration occasionally accompanies the terminal stages of congestive heart failure. We describe this association in a patient requiring heart transplantation. The gradual abatement of Cheyne-Stokes respiration after transplantation supports the delayed circulatory time theory as the mechanism for Cheyne-Stokes respiration in these patients.

Cheyne-Stokes Respiration↗
PubMed1985

Controlled trial of dexamethasone in respirator-dependent infants with bronchopulmonary dysplasia.

A randomized trial was conducted of dexamethasone therapy in infants with bronchopulmonary dysplasia who were dependent on respirators and were not progressing clinically despite conventional treatment. Babies were admitted to the study if they had a roentgenogram and clinical diagnosis of bronchopulmonary dysplasia, were 2 to 6 weeks in age, weighed less than 1,500 g, had made no progress in weaning for the preceding five days, and were free of sepsis, patent ductus arteriosus, and congenital heart disease, and had had no intravenous fat for at least 24 hours. After parental consent was obtained, infants were randomly assigned to control or treatment groups. The study hypothesis was that with steroid treatment, babies could be weaned from the respirator within 72 hours and would show a significant improvement in lung compliance within that time. Sequential analysis exceeded criterion (P less than .05) when seven consecutive untied pairs showed weaning with dexamethasone and failure to wean in control infants. Pulmonary compliance improved by 64% in the treated group and 5% in the control group (P less than .01). No significant intergroup differences were noted in mortality, length of hospital stay, sepsis, hypertension, hyperglycemia, or electrolyte abnormalities. Study design permits the conclusion that dexamethasone can produce substantial short-term improvement in lung function, often permitting rapid weaning from the respirator, but long-term efficacy and safety must be demonstrated by further investigations.

Bronchopulmonary Dysplasia↗
PubMed1976

[Neuro-psychological development of a group of children with neonatal respiratory distress treated with intermittent positive-pressure respirator].

The first results of long-term evolution of 99 children, most of which were premature, and who survived after intermittent positive pressure respiration for hyaline membrane disease, have been analyzed. No matched series could be set up. With a follow-up ranging from 3 1/2 years to 6 years, 51% of the children were normal, 12.5% presented with severe neurological and psychological sequellae, 31% had acceptable, sometimes slight handicap. As compared with series of the literature, prognosis was improved with intensive care and artificial respiration. This is far more obvious for the children at stage III, of which none survived without artificial respiration.

Child↗
PubMedDate not supplied

[External respiration and gas exchange in space flights].

This is an overview of investigations performed in actual and simulated flights to study the effects of microgravity and acceleration, space cabin and space suit artificial atmosphere on the respiratory function. The conceptual prediction of the effects that the space environment produces on the respiratory system suggests the following changes in respiration, gas exchange, and acid-base equilibrium: respiration biomechanics; gas diffusion and ventilation-perfusion ratios in the lungs; regulation of respiration and function of respiratory muscles; lung hydration and blood filling; respiratory changes in acid-base equilibrium and blood gases. Besides, the combined effect of microgravity, acceleration, low barometric pressure and modified gas composition may cause lung atelectases and concomitant disorders in pulmonary ventilation and gas exchange. These changes may have an adverse effect on the health condition and physical work capacity.

Acceleration↗
PubMed1977

[Cheyne-Stokes respiration in chronic heart insufficiency].

1.26 of 340 patients with chronic heart failure (aortic-valve or mitral-valve disease, congestive cardiomyopathy) showed Cheyne-Stokes respiration in supine position. 2. The incidence of Cheyne-Stokes respiration in males is more than twice as high as in females with similar hemodynamic conditions. 3. Lung volumes and airway resistance did not appreciably deviate from the predicted values and are therefore of no etiologic significance. 4. Delay of the feedback between changes in the alveolar gas tensions and respiratory center caused by a prolonged circulation time (decreased cardiac index and increased central blood volume) is the predominant cause of Cheyne-Stokes breathing in patients with chronic heart failure. 5. Metabolic alkalosis (e.g. after diuretics) favors Cheyne-Stokes respiration in patients with congestive heart failure and low cardiac output, by lessening respiratory changes in pH of blood and cerebrospinal fluid.

Aged↗
PubMed1958

Resuscitation of newborn premature infants; a clinical study of the use of positive pressure respiration.

The Goddard-Bennett-Lovelace hand resuscitator was used for initiating respiration in 87 newborn infants with respiratory difficulties, during a five-month period at the Los Angeles County General Hospital. On alternate days, when the respirator was not used, 126 comparable infants received resuscitation by mouth-to-tracheal pressure and other means. Neither term infants nor previable infants benefited by use of the hand resuscitator, but premature infants weighing more than 1,000 gm. had a definite advantage, with a mortality of only 13 per cent for those treated with the resuscitator against 34 per cent among the controls. Neither roentgen nor postmortem studies of the lungs disclosed any consistent effect of any resuscitative measure employed.

Asphyxia Neonatorum↗
PubMed1978

Response detection in respiration audiometry.

The respiration of ten adults with normal hearing was monitored to determine how well changes in respiration could be detected after auditory stimulation. Three judges used two methods of response scoring. The first was without knowledge of signal presentation, and the second was with knowledge of signal presentation. Judges detected the presence of respiratory responses not only during signal presentations (hits) but also during silent intervals (false alarms). Hits and false alarms co-varied in a manner predicted by the theory of signal detectability. A low false alarm rate could be purchased only at the expense of a low hit rate. The implications of this finding for the clinical efficacy of respiration audiometry are considered.

Acoustic Stimulation↗
PubMed1997

Study of respirator effect on nasal-oral flow partition.

Factors affecting worker tolerance of respiratory personal protective devices are inadequately understood. This study evaluates whether respirator-type loads affected the switch from nasal to oral breathing. Eleven healthy subjects were studied under progressive exercise conditions, using a respirator full-face mask with inspiratory resistance (I), pressure breathing (P) (10 cm H2O end-expiratory pressure), or no load (N). A rapid-response thermistor was used to determine whether flow was predominantly oral or nasal. Both P and I increased the percentage of time that breathing was predominantly oral. The effect was most pronounced at higher exercise levels. The percentage of mouth breathing appeared to be closely related to the expiratory time. This study suggests that nasal-oral flow partitioning should be considered as a possible determinant of respirator tolerance.

Adult↗
PubMed2000

Detection of a relation between respiration and CSF pulsation with an echoplanar technique.

The flow of cerebrospinal fluid (CSF) through the aqueduct was studied with an echoplanar imaging technique. Images (1024) of a slice perpendicular to the aqueduct were acquired with a repetition time of 107 msec and a flip angle of 90 degrees. This imaging technique is very sensitive for flow into the selected slice, although a quantitative assessment of flow velocities is not possible. Simultaneously with the image data acquisition, data from a pulse oximeter and a respiration belt were recorded. For each data point, a delay time to the preceding cardiac pulse was determined from the recorded pulse wave. The signal intensities could then be assigned to the cardiac cycle. Each cardiac interval was assigned to one of eight respiratory phases, and an average signal curve during the cardiac interval was calculated for each respiration phase. The evaluation showed to signal maxima within the cardiac interval, which could be identified as a downward flow at 10% and an upward flow at 80% of the cardiac pulse interval by measurements with additional saturation pulses. In examinations of 22 healthy volunteers, an influence of respiration on the flow through the aqueduct was found. In spite of interindividual variability, comparable effects could be observed in all volunteers. In the late expiration phase the caudally directed flow was at its maximum, whereas the cranially directed flow was maximal in the post-inspiration phase.

Adult↗