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At least 775 records · Page 43Linked to original sources
PubMed2006

Continuous nebulized albuterol attenuates acute lung injury in an ovine model of combined burn and smoke inhalation.

OBJECTIVE: Albuterol, due to its bronchodilatory and anti-inflammatory effects, is given via continuous nebulization in children with severe asthma. Combined burn and smoke inhalation injury frequently results in acute lung injury due to a combination of airway obstruction and inflammation. We hypothesized that albuterol administered via continuous nebulization would mitigate acute lung injury after smoke inhalation injury and burn. DESIGN: Randomized prospective animal model. SUBJECTS: Twenty adult female sheep (mean weight, 33.1+/-0.9 kg). INTERVENTIONS: Adult ewes were subjected to a 40% body surface area third-degree flame burn and smoke inhalation injury after tracheostomy. Sheep were allocated to a) sham group, b) saline continuous nebulization group, c) 20 mg of albuterol continuous nebulization group, or d) 40 mg of albuterol continuous nebulization group (n=5 animals per group). All groups received intravenous lactated Ringer's solution at 4 mL.kg-1.%burn(-1).24 hrs-1 for resuscitation and were equally mechanically ventilated throughout the 48-hr study period. Pulmonary and cardiac function, lung lymph flow, bronchial obstruction score, and wet/dry lung weights were recorded. RESULTS: Compared with saline and control groups, the albuterol groups had lower pause and peak inspiratory pressures, decreased pulmonary transvascular fluid flux, a significantly higher Pao2/Fio2 ratio, and decreased shunt fraction at 48 hrs postinjury. The wet-to-dry lung weight ratio and bronchial obstruction scores were lower for sheep receiving albuterol. CONCLUSIONS: Continuous nebulization of albuterol improves pulmonary function via improved airway clearance and decreased fluid flux in a combined burn/smoke inhalation injury model.

Administration, Inhalation↗
PubMed2005

Ventilatory and hemodynamic changes during retroperitoneal and transperitoneal laparoscopic nephrectomy: a prospective real-time comparison.

PURPOSE: Nephrectomies are currently performed via the transperitoneal or retroperitoneal laparoscopic approach. We compared the ventilatory and hemodynamic effects of these approaches. MATERIALS AND METHODS: After institutional ethics committee approval was obtained patients requiring nephrectomy in a 9-month period were prospectively allocated to the retroperitoneal (24) or transperitoneal (15) approach. All were initially ventilated in the volume controlled mode (10 ml kg tidal volume). Intraoperative fingertip, pulse derived arterial oxygen saturation less than 97%, end tidal CO2 partial pressure greater than 40 mm Hg and peak inspiratory pressure greater than 36 cm H2O necessitated changes in ventilatory parameters, as deemed necessary by the anesthetist. If tidal volume decreased greater than 25% of baseline, pressure controlled ventilation was begun instead. RESULTS: Peak inspiratory and plateau pressures increased for the transperitoneal approach by approximately 30% more than in the retroperitoneal group (p <0.05). Volume controlled ventilation was changed to pressure controlled ventilation in 8 transperitoneal vs zero retroperitoneal cases (p <0.05). Heart rate, and systolic and diastolic blood pressure increased by approximately 13% more in the transperitoneal than in the retroperitoneal group (p <0.05). CONCLUSIONS: Nephrectomy via the retroperitoneal laparoscopic approach interferes with ventilatory and hemodynamic functions less than nephrectomy via the transperitoneal approach.

Adult↗
PubMedDate not supplied

Location of flow limitation in liquid-filled rabbit lungs.

The effects of end-inspiratory lung volume (EILV) and expiratory flow rate (Q) on the location of flow limitation in liquid-filled lungs were investigated by measuring pressure along the airways and by radiographic imaging. The lungs of New Zealand white rabbits were filled with perfluorocarbon to the randomly selected EILV of 20, 30, or 40 ml/kg, and the volume was actively drained at one of three Q: 2.5, 5.0, or 7.5 ml/s. The minimum pressures recorded by a movable catheter at locations along the airways show that flow limitation occurred in the main bronchi and trachea, and was independent of EILV and Q. The minimum pressure at the trachea was -80 mm Hg compared with values that were more positive than -10 mm Hg at a location 3 cm distal to the carina for all EILV and Q combinations. This location was confirmed by the lung images. The airway diameters gradually decreased with time, until flow limitation occurred. In airways distal to the collapse, there was not a significant decrease in diameter. Based on these data, we conclude that flow limitation in liquid-filled lungs occurs in the trachea and main bronchi and its location is independent of EILV or Q.

Animals↗
PubMed2003

Pulmonary function tests, respiratory muscle strength, and endurance of patients with osteoporosis.

BACKGROUND: It has been shown that patients with thoracic kyphosis due to osteoporosis have diminished pulmonary function. The aim of this study was to determine the pulmonary function, respiratory muscle strength, and endurance of patients with osteoporosis who did not have compression fractures. METHODS: The patient group consisted of 88 recently diagnosed postmenopausal osteoporotic women without spinal fractures. They were matched for age and body mass index with 54 healthy women, who formed the control group. Bone mineral density, pulmonary function test (PFT), maximum voluntary ventilation (MVV), maximal inspiratory pressure (MIP), and maximal expiratory pressure (MEP) measurements of both groups were performed. RESULTS: There were no significant differences between the two groups regarding PFT parameters and MIP and MEP. However, osteoporotic patients had significantly lower MW values. CONCLUSION: Women with postmenopausal osteoporosis without spinal compression fractures have normal PFT, MIP, and MEP values, but they have reduced respiratory muscle endurance.

Aged↗
PubMed2004

Handgrip strength, pulmonary function tests, and pulmonary muscle strength in fibromyalgia syndrome: is there any relationship?

OBJECTIVE: It has been reported that patients with fibromyalgia syndrome (FMS) have lower maximal respiratory pressures than healthy subjects, indicating reduced pulmonary muscle strength. It has also been reported that patients with FMS have reduced grip strength. In this study, we aimed to examine the possible relationship between handgrip strength as a determinant of peripheral muscle strength and pulmonary muscle strength in patients with FMS by comparing them with healthy controls. METHODS: Forty-one consecutive women with FMS (diagnosed according to the American College of Rheumatology 1990 criteria) were compared with 40 age- and body mass index-matched healthy female controls. Pulmonary function tests were assessed by spirometry. Maximal pulmonary pressures were evaluated using an oral pressure meter. A dyspnea score was obtained. Pain was scored according to visual analogue scale and chest pain was classified (0-9) in fibromyalgia patients. Chest expansion was also measured in the two groups. Tender points were also evaluated in FMS patients. Grip strength (Jamar handheld dynamometer) was also measured in the two groups. RESULTS: The difference in pulmonary function tests was not statistically significant between groups. Maximal respiratory pressures (maximum inspiratory pressure and maximum expiratory pressure) and endurance (maximum ventilatory volume) were significantly lower in patients with FMS than in controls. There was also a statistically significant difference between groups regarding grip strength. There was also significant correlation between maximal inspiratory pressure and maximal expiratory pressure values and handgrip strength in patients with FMS. CONCLUSION: These data indicate that handgrip strength may be a determinant of pulmonary muscle strength in fibromyalgia patients.

Adult↗
PubMed1992

The chronaxie for myocardium and motor nerve in the dog with chest-surface electrodes.

The chronaxie (i.e., the duration for a stimulating current having twice the rheobasic, or minimum, value) was determined for ventricular myocardium in 12 pentobarbital-anesthetized dogs. Current was applied transthoracically via chest-surface electrodes located at the optimal axillary site for producing inspiration by stimulation of the phrenic nerve (electroventilation). In four dogs the chronaxie for motor-nerve was determined using electrodes at the same location. After using hand-held electrodes to identify the optimal stimulation site for electroventilation, 4.1 cm diameter electrodes were applied bilaterally to the optimal site on the thorax. In 12 dogs, the threshold current for producing ventricular ectopic beats was determined for single rectangular current pulses ranging from 0.1-10 ms in duration. From these data, strength-duration curves were determined and the average chronaxie for ventricular myocardium was found to be 1.82 ms. In four dogs the relationship between inspired volume and maximum stimulus intensity was determined using a 0.8 s burst of stimuli (60/s) with pulse durations ranging from 20-500 microseconds. From these data, strength-duration curves for current were constructed and the average chronaxie for motor-nerve was found to be 0.17 ms. The results of this study show that, because of the differing chronaxies, the current required to produce inspiration with short-duration stimuli is much less than that required to evoke an ectopic heart beat.

Animals↗
PubMed2004

Pressure-volume relationships in acute lung injury: methodological and clinical implications.

BACKGROUND: Pressure-volume relationships (PV curves) are the only available method for bedside monitoring of respiratory mechanics. Alveolar recruitment modifies the results obtained from the PV curves. We hypothesized that method-related differences may influence PV-curve guided ventilatory management. METHODS: Twelve acute lung injury (ALI) patients [PaO2/FiO2 13.0 +/- 1.5 kPa (97.6 +/- 11.3 mmHg), bilateral pulmonary infiltrates] were studied. Two PV curves [one at variable, and another at constant level of positive end-expiratory pressure (PEEP)] were obtained from each patient using constant inspiratory flow and end-inspiratory and -expiratory occlusions. Upper and lower inflection points (UIP, LIP) were estimated. Recruitment due to PEEP and during inflation was assessed by respiratory inductive plethysmography (RIP). RESULTS: (1) Pressure-volume curves at constant PEEP tended to provide higher LIP values compared with curves at variable PEEP (mean difference +/- SEM 5.1 +/- 1.9 cmH2O); and (2) recruitment occurred throughout the PV curve with no relationship with LIP or UIP. CONCLUSION: Pressure-volume curves obtained using variable PEEP translate a different physiological reality and seem to be clinically more relevant than curves constructed at constant PEEP. If curves constructed at constant PEEP are used to set the ventilator, unnecessarily high PEEP levels may be used. Respiratory inductive plethysmography technology may be used for monitoring of recruitment at the bedside.

Adolescent↗
PubMed1988

Comparative study of the bronchodilating effects of (-)- and (+)-oxyphenonium bromide.

1. Racemic oxyphenonium bromide, its enantiomers and placebo were inhaled by eight adult patients with chronic airflow obstruction, in a four-way double-blind cross-over study. 2. Forced expiratory volume in one second (FEV1) and slow inspiratory vital capacity (VC) were measured during the first 6 h after inhalation. 3. (+)-Oxyphenonium was found to be the active enantiomer (eutomer), providing better bronchodilation than (+/-)-oxyphenonium. 4. The distomer, (-)-oxyphenonium, showed only a slight effect on FEV1 and VC as compared with placebo.

Adult↗
PubMed1994

Effect of short-term treatment with fluticasone propionate nasal spray on the response to nasal allergen challenge.

The aim of the study was to investigate the effect of short-term treatment with fluticasone propionate on the response to nasal allergen challenge in patients with allergic rhinitis. Responses to nasal allergen challenge were assessed subjectively by recording symptom scores on visual analogue scales, and objectively by measuring histamine, PGD2 and LTC4 in nasal lavage and by measuring nasal inspiratory peak flow following challenge. Nasal allergen challenge resulted in an increase in all symptom scores (P < 0.05); an increase in histamine and PGD2 (P < 0.05), and a decrease in nasal inspiratory peak flow at 1 h, 5 h and 7 h following challenge (P < 0.05). The allergen-induced changes in symptom scores, mediator levels and nasal inspiratory peak flow were attenuated by treatment with fluticasone propionate (P < 0.05 for all parameters measured). Post-challenge nasal obstruction was decreased by 45%; sneezing, itching and rhinorrhoea by 73, 78 and 80% respectively in the group as a whole comparing scores whilst on fluticasone propionate with those on no therapy. Fluticasone propionate, 200 micrograms twice daily for 2 weeks is effective in reducing significantly the early and late response to nasal allergen challenge.

Administration, Intranasal↗
PubMed1985

Optimal use of tube spacer aerosols in asthmatic children.

In a double blind cross-over study the bronchodilator response after eight different modes of inhalation of terbutaline from a pressurized aerosol with a tube spacer was assessed in fifteen asthmatic children. Slow inspiratory flow rates (15-30 l/min) were found to be associated with a statistically significant increase in response when compared with flow rates higher than 70 l/min (P less than 0.01). Tilting the head back during the inhalations and a breath-holding pause of 10 sec after the inhalation had no significant effect upon bronchodilation. In addition, bronchodilation was the same whether the children inhaled from RV or FRC, and whether they inhaled as deeply possible or only to about half the maximum volume. The results suggest that efforts should be made to develop a new and more simple set of instructions for the use of tube spacer aerosols.

Adolescent↗
PubMed1991

The objective assessment of nasal patency.

Nasal patency was measured by five techniques in 24 subjects and the results compared. In addition three pulmonary parameters were measured as well as height and weight. Nasal resistance to airflow measured by active anterior rhinomanometry was found to be highly correlated with peak nasal inspiratory flow rate. Other correlations were also noted. Peak nasal inspiratory flow was itself highly correlated with pulmonary peak expiratory flow rate as well as with several other parameters. The possible reasons for these correlations are discussed in terms of fluid mechanics.

Adult↗
PubMed2004

Nasal physiological changes during pregnancy.

Rhinitis in pregnancy has been previously investigated with variable results. This study examines all the variables of the nasal airway simultaneously for the first time. Eighteen women were recruited in the first trimester of pregnancy and followed through to the postpartum period to monitor the changes that occurred. Measurements of the nasal airway included anterior rhinoscopy (AnR), peak inspiratory nasal flow, acoustic rhinometry, anterior rhinomanometry (ARM), and the saccharin test with rhinitis questionnaire scores providing a symptomatic measurement. All the tests showed a trend consistent with decreasing nasal patency when expressed as an average for the group as a whole, although only AnR, ARM, mucociliary clearance time and rhinitis questionnaire scores were statistically significant (P < or = 0.05). This confirms the effect of pregnancy on the nasal mucosa and coincides with the rise in the serum concentration of the female sex hormones with gestational age, returning to normal postpartum. Pharmacological antagonism of oestrogens may therefore relieve nasal congestion and is currently under further research.

Airway Resistance↗
PubMed2005

Repeatability of peak nasal inspiratory flow measurements and utility for assessing the severity of rhinitis.

BACKGROUND: The measurement of peak nasal inspiratory flow (PNIF) provides a simple, cheap, fast and readily available tool for determining the extent of nasal airway patency. However, there are questions regarding its repeatability when used to assess the degree of nasal obstruction in large populations. Therefore, this study aimed to evaluate the repeatability of PNIF measurements and to assess their association with the signs and symptoms of rhinitis. METHODS: The PNIF, rhinitis symptoms, judged by Meltzer questionnaire and rhinitis signs, as determined by anterior rhinoscopy, were assessed in 283 adults representative of the general population. One training and two test PNIF measurements were recorded during the same session. RESULTS: The PNIF was highly reproducible (ICC = 0.92; 95% limits of agreement: +/-36 l/min). The PNIF was strongly correlated with rhinitis signs, measured by anterior rhinoscopy (rs= -0.38, P < 0.0001) but was not correlated with rhinitis symptoms, measured by questionnaire (rs= -0.11, P = 0.057). Differences in PNIF for subjects categorized as asymptomatic, mild or moderate/severe on the basis of rhinitis signs, were highly significant (P < 0.0001), but less significant on the basis of rhinitis symptoms (P = 0.04). A PNIF cut-off of 115 l/min had moderately high specificity (72%) and sensitivity (65%) and a high negative predictive value (90%) for moderate/severe signs of rhinitis. CONCLUSION: In a large general population-based sample of young adults, PNIF was highly reproducible and closely related to the signs of rhinitis, as determined by clinical examination. The PNIF provides information that is qualitatively different to that provided by symptom scores and may be useful to measure the extent of nasal obstruction.

Adult↗
PubMed1980

Pretreatment with non-depolarizing muscle relaxants: the influence on neuromuscular transmission and pulmonary function.

The influence of pretreatment with non-depolarizing muscle relaxants on the neuromuscular transmission was evaluated in 40 healthy, awake, non-premedicated volunteers using train-of-four (TOF) nerve stimulation and measurement of vital capacity (VC), inspiratory force (IF), peak expiratory flow (PEF), and forced expiratory volume in the first second (FEV1). The subjects were randomly allocated to one of four groups: group I received pancuronium 0.01 mg/kg; group II pancuronium 0.015 mg/kg; group III gallamine 0.3 mg/kg, and group IV gallamine 0.4 mg/kg intravenously. TOF ratio decreased significantly in groups II, III and IV but not in group I following precurarization. Median (25 and 75 percentiles) TOF ratios after pretreatment wer 94(92-96), 89 (86-93), 92 (89-93), and 93 (87-96), respectively. Overall there were decreases in VC, IF, and PEF, but only the decrease in PEF was statistically significant in all four groups. FEV1 was unchanged. The most pronounced decrease in VC, IF, and PEF (11, 29, and 29%, respectively) was seen one subject in group II with a TOF-ratio of 63 following precurarization. Four subjects (20%) in groups II and IV experienced difficulty in breathing. All subjects were, however, able to maintain head lift for more than 10 s, and none needed respiratory support. Seventy percent of all subjects had various minor complaints as, for instance, blurred vision and difficulty in swallowing. It is concluded that the higher doses of pancuronium 90.015 mg/kg) and gallamine (0.4 mg/kg) cannot be recommended for routine precurarization.

Gallamine Triethiodide↗
PubMed1987

Pretreatment with atracurium: the influence on neuromuscular transmission and pulmonary function.

The influence of pretreatment with atracurium on neuromuscular transmission was evaluated in 60 healthy volunteers using train-of-four (TOF) nerve stimulation and measurement of respiratory rate (RR), vital capacity (VC), inspiratory force (IF), and peak expiratory flow (PEF). The subjects were randomly allocated to one of four groups: Group I received atracurium 0.02 mg/kg, Group II 0.03 mg/kg, Group III 0.04 mg/kg, and Group IV atracurium 0.05 mg/kg. TOF ratio decreased significantly in all four groups. There was, however, no difference between the groups after injection. PEF decreased significantly in all four groups, VC decreased in Groups I and IV, and RF increased significantly only in Group IV. Three subjects (5%) had shallow, frequent respiration; however, none needed respiratory support. The majority of the volunteers experienced blurring of vision and heavy eyelids: 82% and 67%, respectively. All subjects were able to sustain head lift for 10 s or more after atracurium. Careful observation of respiration is necessary, especially when using the higher doses of atracurium.

Anesthesia↗
PubMed1988

"Closing volume" during high-frequency ventilation in anesthetized dogs.

Airway closure, mean airway pressure, gas exchange and different modes of artificial ventilation were investigated in anesthetized and paralyzed dogs with clinically healthy lungs. The animals were ventilated with either intermittent positive pressure ventilation (IPPV), continuous positive pressure ventilation (GPPV, positive end-expiratory pressure (PEEP) = 0.49 kPa) or high-frequency jet ventilation (HFJV, open system) of 2 and 30 Hz with an inspiratory to expiratory (I/E) - ratio of 30/70 and 60/40. Closing volume (CV) was determined by a modified technique, submitting the lung to constant subatmospheric pressure after an inspiratory vital capacity of oxygen. Two different tests for CV were used: the foreign gas bolus (FGB) with helium as nonresident gas and the single breath nitrogen dilution technique (SBO2). During conventional mechanical ventilation, CV decreased significantly (P less than 0.05) after establishing a PEEP of 0.49 kPa. During HFJV, CV increased significantly (P less than 0.01). This effect was predominantly dependent on I/E duration time ratio and to a lesser extent on ventilatory frequency. There were significant differences between CV obtained by the FGB-method (CV(helium] and CV derived from the SBO2-test (CV(SBO2], although both tests revealed the same proportional changes of CV during the different modes of ventilation. The elevated CV was associated with a decreasing Pao2 and increasing Aa-Do2 and Paco2, indicating substantial hypoventilation and mismatching of ventilation and perfusion. Mean airway pressure increased with both CPPV and HFJV, revealing a dissociation between airway pressure and regional FRC distribution during HFJV. It is concluded that certain modes of high-frequency ventilation lead to impaired distribution of inspired gas to dependent lung regions.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia, Intravenous↗
PubMed1992

Effectiveness of pressure support ventilation for mechanical ventilatory support in patients with status asthmaticus.

We compared the effects of pressure support ventilation (PSV) with those of assist control ventilation (ACV) on breathing patterns and blood gas exchange in six patients with status asthmaticus. Both PSV and ACV delivered adequate minute ventilation (PSV: 7.5 +/- 1.4 l/min/m2, ACV: 7.3 +/- 1.3 l/min/m2) to correct respiratory acidosis (pH = 7.33 +/- 0.12 during both PSV and ACV) and prevent hypoxia. Peak airway pressure during PSV was significantly lower with the same tidal volume than that during ACV (PSV: 30 +/- 10 cmH2O (2.9 +/- 1.0 kPa), ACV: 50 +/- 13 cmH2O (4.9 +/- 1.3 kPa)). The lower airway pressure during PSV was due to persistent inspiratory muscle activity. The oxygen cost of breathing estimated by oxygen consumption was equivalent in both modes. We conclude that PSV is effective in supplying tidal volumes adequate to improve hypercarbia at markedly lower airway pressures than ACV.

Adolescent↗