This study compared the effects of high frequency oscillatory ventilation (HFOV) and intermittent mandatory ventilation (IMV) on the homeostasis of nitric oxide (NO) in the lower respiratory tract of healthy rabbits. The mechanisms underlying a putative stretch response of NO formation in the airways were further elucidated. Male New Zealand ...

From August till November 1998, the Paediatric and Anaesthetic Units of Hospital Kuala Terengganu managed three patients from Kuala Terengganu District who were ventilated for respiratory diphtheria. Their ages were 5, 4 and 7 years old and their immunisation for diphtheria were not complete. All three patients presented with respiratory ...

OBJECTIVE: To observe the nosocomial infection (NI) distribution in ventilated patients of a single intensive care unit (ICU) according to the kind of control of the upper airways: noninvasive positive pressure ventilation (NPPV) versus endotracheal intubation (ETI). SETTING: ICU of a general hospital. DESIGN: Prospective clinical and epidemiologic survey. PATIENTS: ...

Respiratory physiological deadspace (VDphys) during normocapnic ventilation under anaesthesia was studied in 253 patients scheduled for elective non-thoracic surgery. Subjects were ventilated with SERVO 900B ventilator using CO2 analyser 930 (Siemens-Elema Sweden) to adjust minute volume sufficient to maintain end-tidal carbon dioxide fraction (FECO2) around 5.5kPa with normocapnic confirmation using ...

In this pilot study we investigated the hypothesis that intrinsic and extrinsic brainstem lesions situated within the pontomedullary region would effect the integrity of respiratory sinus arrhythmia. The study sample consisted of three patients with anatomic brainstem abnormalities associated with isolated Chiari I malformation, Chiari II malformation with syringobulbia, and ...

Considerable heterogeneity unrelated to the effect of gravity has been demonstrated for both local ventilation (V) and perfusion (Q) in the lung. Local ventilation and perfusion are well matched, so that the heterogeneity of the V/Q ratio is less than for ventilation or perfusion alone (Melsom et aL 1997). We ...

OBJECTIVE: To evaluate the effect of acute changes in minute ventilation (VE) on oxygen consumption (VO2), carbon dioxide production (VCO2), respiratory quotient, and energy expenditure during volume-controlled mechanical ventilation in the critically ill surgical patient. The effects on some oxygen transport variables were assessed as well. DESIGN: Prospective, randomized clinical ...

OBJECTIVE: Work of breathing (WoB) is currently employed to assess the afterload on the respiratory muscles and to estimate the energy expenditure for breathing. Since WoB depends on the ventilated tidal volume (TV), WoB*L(-1), the indicized form of WoB has been employed as a measure of WoB which is independent ...

We have measured how a low concentration of nitrous oxide affected respiratory sensation and ventilation. Severe dyspnoea was induced in nine normal subjects by a combination of hypercapnia and inspiratory elastic load (50 cm H2O litre-1). Subjects were asked to rate their sensation of respiratory discomfort using a visual analogue ...

OBJECTIVE: To determine the effects of tracheostomy on respiratory mechanics and work of breathing (WOB). DESIGN: A before-and-after trial of 20 patients undergoing tracheostomy for repeated extubation failure. SETTING: Surgical intensive care unit at a university teaching hospital and a level I trauma center. PATIENTS: A consecutive sample of 20 ...

To evaluate the possibility of respiratory-volume measurement using photoplethysmography (PPG), PPG signals from 16 normal volunteers are collected, and the respiratory-induced intensity variations (RIIV) are digitally extracted. The RIIV signals are studied while respiratory volume is varied. Furthermore, respiratory rate, body posture and type of respiration are varied. A Fleisch ...

This study examined changes in ventilation produced by negative gamma-aminobutyric acid(A) (GABA(A)) modulators in rhesus monkeys. The effects of Ro 15-4513, beta-CCE and beta-CCM were examined in four rhesus monkeys breathing air or 5% CO2 in air. When monkeys breathed CO2, minute volume (VE) and frequency (f) increased, on average, ...

We evaluated the effect of percutaneous transvenous mitral commissurotomy (PTMC) on ventilatory variables and dyspnea during recovery from a 6-minute submaximal constant workload exercise, and showed that the decrease in postexercise ventilation after PTMC was closely related to improvement in postexercise dyspnea after PTMC. Ventilation during recovery from submaximal constant ...

Breathlessness arises from increased medullary respiratory center activity projecting to the forebrain (respiratory corollary discharge hypothesis). Subjects with congenital central hypoventilation syndrome (CCHS) lack the normal hyperpnea and breathlessness during hypercapnia. The corollary discharge hypothesis predicts that if CCHS subjects have normal hyperpnea during exercise, they will experience normal breathlessness ...

In the clinical literature there are reports of patients failing to breathe and becoming comatose when supplied with 100% oxygen for respiratory distress. This effect has been attributed to a loss of respiratory drive. Recent studies have established that this explanation is incorrect, but have left the phenomenon unexplained. We ...

OBJECTIVE: Patients with heart failure frequently complain of orthopnoea. The objective was to assess the ventilatory response of patients with chronic heart failure during erect and supine exercise. DESIGN: Maximal incremental exercise testing with metabolic gas exchange measurements in erect and supine positions conducted in random order. SETTING: Tertiary referral ...

A decerebrate, spontaneously breathing tadpole preparation (Taylor-Kollros stages 16-19) was used to test the general hypothesis that the efferent bursting activities of cranial nerves (CN) V, VII and spinal nerve (SN) II are respiratory in nature, and, in particular, to identify separate and specific neural correlates of gill and lung ...

We studied 19 patients anaesthetised for routine surgery using isoflurane delivered from a Komesaroff vaporiser mounted within a circle system. Their lungs were ventilated using a Penlon Nuffield ventilator attached to the circle system by a trunk of tubing. Fresh gas flow rates of 1, 2 or 31.min-1 were used. ...

This single-subject case examined oxyhemoglobin saturation and alveolar end-tidal carbon dioxide levels in a ventilator-dependent tetraplegic patient undergoing electrical stimulation cycle ergometry. When exercising with a closed tracheostomy cuff under resting ventilator settings (resting intermittent mandatory ventilation; frequency = 6breaths/min, tidal volume = 83.3mL, minute ventilation =5L/min), his oxyhemoglobin saturation ...

STUDY OBJECTIVES: To elucidate the efficacy of the combination of inhaled nitric oxide (NO) and partial liquid ventilation (PLV) in ARDS. DESIGN: Prospective, randomized, controlled study. SETTING: A research laboratory at a university medical center. SUBJECTS: Thirty-two rabbits. INTERVENTIONS: Animals were anesthetized and ventilated via tracheostomy (tidal volume=40 mL; respiratory ...

The incidence and clinical significance of hemidiaphragmatic paresis after supraclavicular block of the brachial plexus is unknown. Eight healthy volunteers received a supraclavicular block with a standard technique using 30 mL of 1.5% lidocaine. Respiratory function was assessed with ultrasound of the diaphragm, respiratory inductive plethysmography (RIP), and pulmonary function ...

We investigated the effect of mechanical unloading and loading on Cheyne-Stokes respiration (CSR) in seven intubated patients with preexisting CSR. For mechanical loading patients had to breathe against the resistance of the endotracheal tube. For mechanical unloading patients were supported with a volume-proportional pressure support in the proportional assist ventilation ...

OBJECTIVE: To compare the cardiopulmonary effects of high-frequency oscillatory ventilation (HFO) and conventional ventilation (CV) in a piglet model of meconium aspiration syndrome. DESIGN: Prospective, randomized control study. SUBJECTS: Piglets 1 to 2 wks of age. INTERVENTIONS: Meconium aspiration was induced in 30 piglets. They were then randomized to CV, ...

Elevated end-tidal partial pressure of CO2 (PET(CO2)) causes air hunger; this sensation becomes intense with a relatively small rise in PET(CO2) if ventilation is held constant. Spontaneously breathing subjects increase ventilation in response to CO2, thereby greatly diminishing air hunger. In healthy subjects and ventilator-dependent patients, experimenter-induced increases in ventilator ...

BACKGROUND: Although clinical cardiopulmonary resuscitation always includes ventilation with pure oxygen, this kind of ventilation has been reported to be associated with worse neurological outcome than ventilation with air in experimental cardiopulmonary resuscitation (CPR). The aim of the present investigation was to compare the systemic oxygen uptake during experimental closed-chest ...

Our clinical experience has shown that the use of a constant distending airway pressure of 30 cm water for 10 s, termed a timed reexpansion inspiratory manoeuvre (TRIM), is often successful in correcting oxyhaemoglobin desaturation in anaesthetized children. The aim of this study was to assess the efficacy of TRIM ...

Changes in body position alters the functional residual capacity (FRC). Most anesthetics reduce FRC in the recumbent but not sitting position. Inspired gas distribution in anesthesia-paralyzed subjects whose lungs are mechanically ventilated, is different from that in the awake state in all but the prone position. The function of the ...

Ventilation during exercise is near-normal in double-lung transplant recipients despite lung denervation. We tested the hypothesis that denervation effects might be unmasked during exercise by exposing these patients to an expiratory load. Eight double-lung recipients and nine intact control subjects were exercised to exhaustion. Ergometer work increased 20 Watt every ...

BACKGROUND: Exogenous catecholamine administration in humans stimulates ventilation. The present study was designed to investigate whether increased endogenous catecholamine release influences objective measures of ventilation and subjective measures of breathlessness in normal subjects. METHODS: Yohimbine, a pre-synaptic alpha 2 adrenoceptor antagonist, or placebo was administered to 10 normal male subjects ...

The extent to which lizards ventilate their lungs during locomotion is controversial. Direct measurements of airflow across the nostrils suggest a progressive reduction in tidal volume and minute ventilation with increased running speed, while other studies have demonstrated that arterial PO2 remains constant during exercise. To resolve these conflicting findings, ...

STUDY OBJECTIVE: The aim of this study was to determine whether intermittent positive pressure ventilation through a nasal mask (NIPPV) applied during exercise in patients with pulmonary tuberculosis sequelae (PTS) could improve arterial blood gas measurements, ameliorate breathlessness, and increase exercise endurance. PATIENTS: Seven PTS patients with a severe restrictive ...

The fast initial increase in ventilation at the start of exercise is generally assumed to be of reflex origin (exercising limbs) and/or caused by a 'feedforward' mechanism increasing breathing via brainstem respiratory centres or cortical areas controlling respiratory muscles. We wanted to test whether this ventilatory increase is in part ...

Increases in arterial plasma potassium during exercise may provide an important drive to ventilation. We examined the changes in arterialized venous plasma potassium concentration ([K +]av) and ventilation that occur during sustained exercise at workloads above and below the ventilatory threshold (Vt) in young health humans. After the onset of ...

OBJECTIVE: To study diaphragmatic strength and endurance after a prolonged period of mechanical ventilation. DESIGN: Prospective animal study. SETTING: Animal research laboratory. SUBJECTS: Seven uninjured adult baboons (Papio cynocephalus) were anesthetized with ketamine, sedated, paralyzed, and mechanically ventilated. Animals were monitored with pulmonary arterial and peripheral arterial catheters. INTERVENTIONS: Mechanical ...

The pattern of breathing following a 10-breath voluntary hyperventilation period during hyperoxic rebreathing was compared to that without hyperventilation in 6 subjects (3 male and 3 female). The aim was to measure the posthyperventilation short-term potentiation of ventilation without changes in respiratory chemoreflex drives induced by the voluntary hyperventilation. Hyperoxia ...

Nitric oxide (NO) inhalation and high frequency oscillatory ventilation (HFOV) has been indicated in infants with severe respiratory failure. The purpose of the present study was to evaluate the safety of an NO inhalation system with HFOV in terms of nitrogen dioxide (NO2) production. The NO inhalation system consisted of ...

Twenty-six male workers from the North Sea offshore oil industry took part in a simulated escape exercise at the Offshore Fire Training Centre. The course was 370 m long and had 19.4 m of vertical ascent and descent using the stairs on simulated offshore structures. Inspired ventilation and oxygen consumption ...

The increase in ventilation caused by exercise is controlled by a combination of neural and chemical events, although the precise contribution and relative importance of these signals is still debated. It is generally agreed that the genesis of exercise hyperpnoea lies within the central nervous system and that peripheral reflexes, ...

OBJECTIVE: To determine whether there is an improvement in oxygenation when partial liquid ventilation and high-frequency oscillatory ventilation are combined in the treatment of acute lung injury, compared with high-frequency oscillatory ventilation alone. DESIGN: Controlled animal trial. SETTING: Research laboratory in a university setting. SUBJECTS: Ten 3-kg piglets. INTERVENTIONS: Anesthetized ...

There are many distinct differences (morphologic, physiologic, and mechanical) between the bird's lung-air-sac respiratory system and the mammalian bronchoalveolar lung. In this paper, we review the physiology of the avian respiratory system with attention to those mechanisms that may lead to significantly different results, relative to those in mammals, following ...

The purpose of the present study was to investigate the effect of exercise induced hyperventilation and hypocapnia on airway resistance (Raw), and to try to answer the question whether a reduction of Raw is a mechanism contributing to the increase of endurance time associated with a reduction of exercise induced ...

The Computer-Based Respiratory Measurement System (CBRMS) is capable of analyzing individual breaths to monitor the kinetics of oxygen uptake, carbon dioxide production, tidal volumes, pulmonary ventilation, and other respiratory parameters during rest, exercise, and recovery. Respiratory gas volumes are measured by a calibrated turbine transducer while the respiratory gas concentrations ...

The ventilation-exchange bougie is a new airway device which can be mounted on a fibreoptic laryngoscope for passage through the larynx into the trachea via a laryngeal mask airway. Subsequent removal of the fibreoptic laryngoscope and laryngeal mask airway allows a tracheal tube to be railroaded into position over the ...

We have used diabetic autonomic neuropathy as a model of chronic pulmonary denervation to study the ventilatory response to incremental exercise in 20 diabetic subjects, 10 with (Dan+) and 10 without (Dan-) autonomic dysfunction, and in 10 normal control subjects. Although both Dan+ and Dan- subjects achieved lower O2 consumption ...

The purpose of this study is to examine the relationship between breathlessness and the ventilatory response to hypercapnia or hypoxia in patients with chronic obstructive pulmonary disease (COPD). Fifteen male patients (mean forced expiratory volume in one second (FEV1): 1.13 L) underwent tests to determine hyperoxic hypercapnic ventilatory response (HCVR) ...

Exercise intolerance is a common finding in mitochondrial diseases, including Kearns-Sayre syndrome (KSS), characterised by progressive external ophthalmoplegia, cardiac conduction defects and atypical pigmentary degeneration of the retina. Exercise studies were performed in a 32 year old woman with KSS who had received an atrio-ventricular sequential pacemaker because of continuing ...

Assessments of inhalation exposure to environmental agents necessitate quantitative estimates of pulmonary ventilation rates. Estimating a range of exposures in a given population requires an understanding of the variability of ventilation rates in the population. Distributions of ventilation rates (Ve) were described based on the results of a large study ...

Ventilatory support during cardiopulmonary resuscitation can be accomplished with an array of methods and devices. These run the gamut from expired air resuscitation, including mouth-to-mouth and mouth-to-mask, to the use of ventilators including ventilator-to-mask and ventilator-to-artificial airway techniques. Appropriate application of these techniques depends on the clinical situation, rescuer training, ...

We report herein the findings of a 2-year-old boy in whom junctional tachycardia developed 2 days after he underwent a modified Fontan operation and thereafter was successfully treated by hypothermia without paralyzing and artificially ventilating the patient. Chlorpromazine was useful in achieving moderate hypothermia by surface cooling without producing any ...

Many reptiles, particularly diving species, display characteristic cardiovascular changes associated with lung ventilation (cardiorespiratory synchrony). Previous studies on freshwater turtles show that heart rate and pulmonary blood flow rate (Qpul) increase two- to fourfold during ventilation compared with breath-holding, and some studies report concomitant decreases in systemic blood flow rate ...