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At least 163 records · Page 9Linked to original sources
PubMed1994

High thoracic epidural anesthesia does not alter airway resistance and attenuates the response to an inhalational provocation test in patients with bronchial hyperreactivity.

BACKGROUND: The functional relevance of an intact pulmonary sympathetic innervation for airway resistance is unknown. We therefore evaluated whether or not pulmonary sympathetic denervation by thoracic epidural anesthesia decreases the threshold of an inhalational provocation with acetylcholine in 20 patients with documented bronchial hyperreactivity scheduled for elective upper abdominal or thoracic surgery. METHODS: Baseline inhalational provocation with acetylcholine was performed 2-4 days before surgery. The acetylcholine threshold concentration for a hyperreactivity response (i.e., for a 20% decrease in forced expiratory volume in 1 s and a 100% increase in total respiratory resistance by oscillometry) was determined. On the day of surgery a second inhalative provocation with acetylcholine was performed 45 min after the patients had received 6-8 ml epidural bupivacaine 0.75% (n = 10), intravenous bupivacaine (1.2 mg.min-1, n = 6), or 6-8 ml epidural saline (n = 4). The acetylcholine threshold concentration for a hyperreactive response was again determined. We also measured vital capacity, forced expiratory volume in 1 s as a percentage of vital capacity, spread of sensory blockade (pin prick), skin temperature on hand and foot (telethermography). RESULTS: During thoracic epidural anesthesia, C4-T8 skin temperature increased significantly on hand and foot indicating widespread sympathetic blockade including the lungs. Compared to values obtained immediately before pulmonary sympathetic blockade, forced expiratory volume in 1 s as a percentage of vital capacity, and total respiratory resistance by oscillometry remained unchanged, while vital capacity decreased. Compared to baseline the acetylcholine threshold concentration for the hyperreactive response increased threefold after epidural as well as after intravenous bupivacaine. Epidural saline evoked no directional changes in the acetylcholine threshold concentration. CONCLUSIONS: We conclude that in patients with bronchial hyperreactivity 1. blockade of pulmonary sympathetic innervation seems to be of no relevance for airway resistance and 2. both epidural and intravenous bupivacaine substantially attenuate the response to an inhalational provocation with acetylcholine.

Acetylcholine↗
PubMed2005

Effects of tension of the girth strap on respiratory system mechanics in horses at rest and during hyperpnea induced by administration of lobeline hydrochloride.

OBJECTIVE: To determine whether tension of the girth strap of a saddle would sufficiently affect rib motion and reduce lung volume to alter pulmonary resistance in horses. ANIMALS: 10 healthy adult horses. PROCEDURE: We used classical techniques to measure the effects of tightening a girth strap (15 kg of tension) on pulmonary dynamics during eupnea and hyperpnea in horses. Respiratory impedance was evaluated by use of oscillometry, and resistance and reactance data were partitioned into lung and chest wall components. Rib cage and abdominal contributions to tidal volume and minute ventilation were measured by use of respiratory inductance plethysmography. Effects of strap tension on functional residual capacity (FRC) were measured during eupnea by use of a helium-dilution technique. In a subgroup of 6 horses, we also measured transdiaphragmatic pressures during eupnea and hyperpnea induced by administration of lobeline hydrochloride (0.2 mg/kg, i.v.). RESULTS: Pulmonary resistance measured by use of oscillometry but not by use of classical methods was significantly increased by the tension of the girth strap. However, the increase in pulmonary resistance could not be explained by a decrease in FRC. Motion of the rib cage was significantly reduced during eupnea and hyperpnea. However, ventilatory variables (tidal volume, minute ventilation, and peak flows), FRC, and transdiaphragmatic pressures were unaltered by strap tension. CONCLUSIONS AND CLINICAL RELEVANCE: Although tension of the girth strap caused measurable changes in respiratory mechanics (loss of rib motion and increased pulmonary resistance), there was no evidence that ventilation was limited.

Animals↗
PubMedDate not supplied

[Determination of the steno-occlusive degree using non-invasive methods in diabetic patients with peripheral arterial insufficiency].

58 diabetic patients with peripheric arteriopathy are studied by means of segmentary pressure and oscillometry. Best results for proximal levels were those obtained with segmentary pressure index, whereas oscillometry was better for distal level (ankle and foot). The application of these criteria would facilitate the detection of arterial occlusions without need arteriography.

Aged↗
PubMed1979

Treatment and sequelae of angiographic complications in children.

Fourteen cases of thromboembolic complications appeared in 267 consecutive angiographies during a 7-yr period. The arterial circulation has been evaluated both clinically and with oscillometry. The complication rate was substantially higher after cut down then after percutaneous approach (56% vs. 2.7%). Seven patients with signs of total vascular obstruction were subjected to acute thromboectomy whereas three patients with milder clinical symptoms were treated nonoperatively with anticoagulants. Four patients have died during the examination period, the remaining ten patients have been subjected to long term follow-up (mean follow-up period 3 yr). Seven demonstrated normal findings clinically, as well as oscillographically, whereas three patients subjected ot thromboectomy after cut down were clinically normal but decreased oscillographic pulsations could be demonstrated.

Adolescent↗
PubMed1996

Use of the monofrequency forced oscillation technique to measure changes in upper airway resistance in Friesian and blue Belgian calves.

Monofrequency forced oscillometry (MFO) using a sinusoidal test signal of one frequency (10 Hz) was compared with the classical pulmonary function technique (using an oesophageal balloon with airflow measurements) in two breeds of cattle which differ in their respiratory physiology, particularly to assess changes in upper airway resistance. Six healthy male Friesian calves (mean [SD] bodyweight 131 [12] kg) and six healthy male blue Belgian calves (mean [SD] bodyweight 137 [13] kg) were examined successively with their heads either in a normal position or held vertically, using a cross-over study design. In the normal position, higher resistances, a higher respiratory impedance, and lower values of the dynamic lung compliance (Cdyn) were measured in the blue Belgian than in the Friesian calves. In the vertical head position, total pulmonary resistance (RL) increased and Cdyn decreased significantly (P < 0.05). The changes in MFO-derived parameters were in accordance with the changes in classical parameters, and for both methods, the percentage changes were markedly higher in the blue Belgian calves.

Airway Resistance↗
PubMedDate not supplied

Longitudinal studies of reproducibility and variability of indirect (oscillometric) blood pressure measurements in dogs: evidence for tracking.

To be clinically reliable, blood pressure readings taken in quiet surroundings with good technique from healthy, unstressed subjects accustomed to the procedure, should be reasonably constant between occasions. Apart from changes attributable to age or stress, sustained rises suggest hypertension. Yet it is increasingly realised that arterial pressure shows great short-term lability. Despite this, 'tracking' occurs in groups of humans, i.e. when ranked by blood pressure they tend to maintain their rank order. This paper examines month-on-month variability of arterial pressure, measured by non-invasive oscillometry (Dinamap) in both pet dogs and kennel populations. 'Tracking' occurred and there was also evidence of 'white coat' effects. Heart rate was more variable than arterial pressure and should not be used to reject pressure readings unless changes are extreme. There was further evidence that canine blood pressure rises with age.

Aging↗
PubMed1990

Comparison of oscillation with three other methods for measuring nasal airways resistance.

In this study we have compared the sensitivity and reproducibility of nasal airways resistance measurements made using an oscillometer, with those made by passive anterior, active anterior and active posterior rhinomanometry. Nasal airways resistance values were compared in 12 patients with rhinitis and 15 normal subjects, of whom ten had additional measurements after a vasoconstrictor spray, oxymetazoline. The coefficients of variation of 6-8 technically satisfactory measurements were 9-19%. The decongestant effect of oxymetazoline was detected by all methods, with no decrease in reproducibility. Post vasoconstrictor nasal airways resistance fell by 28% (passive anterior), 35% (active anterior), 36% (active posterior) and 58% (oscillometry). In conclusion, the oscillation method for deriving nasal airways resistance is a useful, new, simple and noninvasive way of assessing nasal airways patency. Results compare favourably with other, more established techniques.

Adult↗
PubMed1997

Blood pressure measurement in the hemodialysis setting.

Blood pressure measurement is an important component of the care of the hemodialysis patient. Invasive methods, as used in the intensive care setting, are the most accurate. In the ambulatory setting, noninvasive methods, such as palpitation, auscultation, and oscillometry, are used. When care is taken to avoid operator error, these techniques should yield results that are sufficiently accurate for clinical use. All new devices should be validated for accuracy.

Auscultation↗
PubMed1997

Discriminative microcirculatory screening of patients with refractory limb ischaemia for dorsal column stimulation.

OBJECTIVES: (1) To determine the proportion of patients with critical limb ischaemia refractory to invasive treatment that can be successfully treated by dorsal column stimulation (DCS), and (2) to identify potential responders to DCS by a simple test that is sufficiently predictive to limit the need for a prolonged trial stimulation period. PATIENTS AND METHODS: Twenty patients with chronic limb-threatening ischaemia were assessed by a battery of macro- and microcirculatory tests and a DCS trial of 1 week. Favourable response during the trial determined selection for long-term stimulation. RESULTS: During a mean observation period of 14 months, limb salvage rate (LSR) was 63% overall and 83% among patients selected after a favourable trial. Of the tests performed preoperatively, digital subtraction angiography, Doppler assessment, oscillometry, capillaroscopy, foot temperature, and transcutaneous partial pressure of oxygen (tcpO2) in the supine or sitting position did not adequately predict DCS response. The supine-sitting tcpO2 gradient (delta tcpO2) was a good predictor of DCS outcome, with an 88% LSR when delta tcpO2 > 15 Torr, dropping to 12% when delta tcpO2 < or = 15 Torr. CONCLUSIONS: DCS is a rewarding therapeutic option in selected patients with critical limb ischaemia. delta tcpO2 appears to reliably predict response to DCS and may obviate trial stimulation in most cases.

Adult↗
PubMed2006

Effect of montelukast on peripheral airflow obstruction in children with asthma.

BACKGROUND: Montelukast is a widely used controller agent in childhood asthma. It is modestly effective in reducing symptoms, decreasing the need for rescue albuterol, and improving forced expiratory volume in 1 second (FEV1). OBJECTIVE: To determine whether montelukast therapy improves peripheral airway obstruction as measured by lung volumes, air trapping, airway resistance (Raw), and specific conductance (Sgaw). METHODS: Twenty-one children aged 9 to 18 years with mild-to-moderate asthma were randomized into a double-blind, placebo-controlled study to receive montelukast (5 or 10 mg) or matching placebo daily for 8 weeks. Symptoms and albuterol use were recorded twice daily, and exhaled nitric oxide measurement, forced oscillometry, spirometry, and body box plethysmography (before and after beta-agonist use) were performed at randomization and at 2, 4, 6, and 8 weeks. Circulating eosinophil counts and serum eosinophil cationic protein (ECP) levels were obtained at randomization and at 8 weeks. RESULTS: Montelukast-treated patients had lower residual volume (P = .05), residual volume-total lung capacity ratio (P = .04), Raw (P = .02), Sgaw (P = .03), and serum ECP levels (P = .02) at 8 weeks compared with those treated with placebo. There was a trend toward reduced daytime and nighttime albuterol use, although the difference did not reach statistical significance. There were no significant differences in FEV1, FEV1-forced vital capacity ratio, exhaled nitric oxide levels, or daytime and nighttime symptom scores between the 2 groups. CONCLUSIONS: Montelukast therapy was associated with less air trapping, hyperinflation, and Raw and better Sgaw compared with placebo. Lower serum ECP levels, a surrogate measure of airway inflammation, were associated with improvements in lung function.

Acetates↗
PubMed2000

Lung function measured by the oscillometric method in prematurely born children with chronic lung disease.

Premature birth is related to a chronic respiratory morbidity, which may persist until school-age. In these children, the forced oscillation technique would be suitable for evaluation of lung function even at preschool age, since it requires only minimal patient cooperation. In order to investigate the oscillometric findings related to premature birth, using the oscillation technique and conventional lung function methods 49 school-aged children born prematurely with (n=15) or without (n=34) chronic lung disease (CLD), and 18 healthy children born at full term were studied. Children with CLD had higher respiratory resistance (Rrs,5) and lower reactance (Xrs,5) than prematurely born children without CLD or healthy controls. Both Rrs,5 (r=-0.55, p<0.0001) and Xrs,5 (r=0.76, p<0.0001) were significantly associated with forced expiratory volume in one second (FEV1), the agreement with spirometry being better in Xrs,5 than in Rrs,5 (p=0.02). Rrs,5 was significantly related to airway resistance (Raw) measured by body plethysmography (r=0.63, p<0.0001), but underestimated resistance at high values of Raw. There was no significant relationship between the pulmonary diffusing capacity and the oscillometric findings. Compared to conventional methods, the oscillometric method yields concordant information on the severity of lung function deficit in children born prematurely, with or without chronic lung disease. In these children, the oscillometric findings are probably due to peripheral or more widespread airway obstruction. As conventional methods are not usually suitable for preschool children, oscillometry may serve as an alternative for early evaluation of chronic lung disease among children with premature birth in clinical or research settings.

Analysis of Variance↗
PubMed2005

Low-cost oscillometric non-invasive blood pressure monitors: device repeatability and device differences.

Automated non-invasive blood pressure measuring devices based on the oscillometric technique are used widely for self-measurement and are often used in clinics in place of the manual, auscultatory method. Oscillometry was originally developed for monitoring purposes and there are questions over its suitability for making diagnostic measurements. This study measured the differences between automated devices, in the absence of physiological variability. We studied 19 low-cost, automated, non-invasive blood pressure devices, using a repeatable artificial arm simulator, and measured the within-device repeatability and between-device differences. We found that the devices were repeatable (mean within-device difference 1 mmHg), but between-device differences were 4.4 mmHg (systolic pressure) and 3.6 mmHg (diastolic pressure), for normal and high-normal blood pressures. Individual devices are sufficiently repeatable for clinical trend use, but differences between devices are sufficiently large that they may be misinterpreted as clinically significant.

Blood Pressure Determination↗
PubMed2002

Inflationary oscillometric blood pressure monitoring: validation of the OMRON-MIT.

BACKGROUND: To evaluate the accuracy of the OMRON-MIT, (an automated inflationary oscillometric blood pressure monitoring device) for use in the general population by direct comparison to standard auscultatory mercury sphygmomanometry. DESIGN: Two trained, blinded observers taking simultaneous blood pressure measurements alternating between a mercury sphygmomanometer and the OMRON-MIT. METHODS: The evaluation was carried out according to the revised British Hypertension Society protocol. The validation data was also classified by the American Association for the Advancement of Medical Instrumentation (AAMI). RESULTS: The OMRON-MIT device achieved a BHS grade A for both systolic blood pressure (SBP) and diastolic blood pressure (DBP). It also met the criteria for the AAMI protocol, the mean difference between the MIT and standard was -2.0 +/- 7 mmHg for SBP and -2.0 +/- 6 mmHg for DBP. CONCLUSIONS: Inflationary oscillometry is a valid technique for the measurement of blood pressure. The OMRON-MIT, which uses this technique, is accurate and can be recommended for clinical use in the adult population.

Adult↗
PubMed2003

Are automated blood pressure measurements accurate in trauma patients?

BACKGROUND: Automated blood pressure (BP) determinations by oscillometry are reported to be as accurate as invasive monitoring for systolic pressures as low as 80 mm Hg. Automated BP devices are widely used by prehospital providers and in hospital operating rooms, emergency departments, and intensive care units, although the accuracy of automated BP has not been demonstrated in trauma patients. We hypothesized that automated BP is less accurate than manual BP in trauma patients. The purpose of this study was to determine the accuracy of automated BP versus manual BP in trauma patients. METHODS: A retrospective review of patients who met trauma activation criteria admitted to a Level I trauma center over a 30-month period was conducted. Patients were included if both manual BP and automated BP were measured within 5 minutes of admission. Additional data collected included Injury Severity Score, base deficit, and emergency department resuscitation volume. Statistical analysis was performed using paired t test, chi2, and linear regression analysis. Significance was attributed to a value of p < 0.05. RESULTS: From January 2000 through June 2002, 388 patients met inclusion criteria. Patients were grouped by manual BP levels: group 1, BP < or = 90 mm Hg (n = 92); group 2, BP 91-110 mm Hg (n = 119); and group 3, BP > or = 110 mm Hg (n = 177). The mean automated BP measurements were significantly higher than the manual measurements in groups 1 and 2 (26 and 16 mm Hg, respectively; p < 0.001). Of the 92 patients with manual BP < or = 90, 45 (49%) had automated BP > or = 100. The base deficit (-5, -3, and -2 for groups 1, 2, and 3, respectively; p < 0.01), Injury Severity Score (30, 25, and 18; p < 0.01), and volume of resuscitative fluid and blood (p < 0.001) all decreased with higher BP group. CONCLUSION: Injury severity, degree of acidosis, and resuscitation volume were more accurately reflected by manual BP. Automated BP determinations were consistently higher than manual BP, particularly in hypotensive patients. Automated BP devices should not be used for field or hospital triage decisions. Manual BP determinations should be used until systolic blood pressure is consistently > or = 110 mm Hg.

Adult↗
PubMed2002

Comparative evaluation of ultrasonography and lung function testing with the clinical signs and pathology of calves inoculated experimentally with Pasteurella multocida.

Seventeen calves were inoculated intratracheally with Pasteurella multocida 0 on three consecutive days with 10 ml of an inoculum containing 10(9) colony forming units/ml per day per calf. Before the first inoculation and 24 hours after the third, each calf was examined non-invasively by means of a clinical examination, chest ultrasonography, and impulse oscillometry to measure the impedance of the respiratory system. The inoculation of P multocida caused fever and a significant increase in respiratory rate and a decrease in tidal volume. There were also significant changes in the ultrasonographic results and in the impedance of the respiratory system. The percentage of the total surface area of the lungs showing pathological changes when the calves were euthanased 48 hours after the third inoculation ranged from 0.4 to 39 per cent. There were statistically significant correlations between the ultrasound scores and the pathological findings and between the ultrasound scores and the respiratory rate and tidal volume. The changes in the impedance of the respiratory system were not correlated with either the ultrasonographic or the pathological findings.

Animals↗
PubMed1993

Bias and variability in blood pressure measurement with ambulatory recorders.

This study sought to determine whether patient characteristics such as age, sex, blood pressure, and pulse pressure differently affect the accuracy of an oscillometric (SpaceLabs 90207) and a microphonic (TM2420 version 7) blood pressure monitor. Blood pressure recorded by two oscillometric and two microphonic ambulatory monitors was compared with simultaneous readings by two pairs of trained, blinded observers using random-zero sphygmomanometry. One hundred and eighteen subjects (53 men and 65 women, aged 17 to 94 years; systolic pressure, 89 to 211 mm Hg; diastolic, 44 to 116 mm Hg) were studied. There were no significant differences within each observer pair or between the two observer pairs as well as no correlation between interobserver differences and patient characteristics. The differences between the monitor and trained observers' readings were 2.8 +/- 9.9 mm Hg systolic and 3.9 +/- 6.8 mm Hg diastolic for the SpaceLabs and 5.0 +/- 5.2 mm Hg systolic and 3.4 +/- 6.1 mm Hg diastolic for the TM2420. Patient characteristics that predicted measurement error were defined by multiple regression. For oscillometry, systolic measurement error was highly correlated with systolic pressure, pulse pressure, and subject age. The diastolic error was significantly correlated with pulse pressure, diastolic pressure, and subject sex. For the oscillometric monitor, patient characteristics accounted for 36.6% of the variation of the systolic error and 34.7% of the variation of the diastolic error. For the microphonic monitor, only age correlated with diastolic error, and no significant correlations were seen with systolic error. Patient characteristics accounted for only 1.2% of the systolic and 8.9% of the diastolic error.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

Comparison of oscillometric and intraarterial systolic and diastolic blood pressures in lean, overweight, and obese patients.

To assess the effect of obesity on blood pressure measurement the authors obtained simultaneous oscillometric and intraarterial systolic and diastolic blood pressures on 188 lean, overweight, class I/II obese, and class III obese subjects. Oscillometric arm cuff/bladder size was selected in accordance with standard guidelines. Oscillometry significantly underestimated systolic and significantly overestimated diastolic blood pressures in each of the 4 weight groups studied. The differences between oscillometric and intraarterial systolic and diastolic pressures were not significantly different among lean, overweight, class I/II obese, and class III obese subjects. Thus, obesity per se does not influence the accuracy of blood pressure measurement. However, oscillometric blood pressure measurement is associated with significant error when compared to intraarterial blood pressure.

Adult↗
PubMed2005

Assessment of arterial stiffness index as a clinical parameter for atherosclerotic coronary artery disease.

BACKGROUND: The aim of the present study was to assess the feasibility and usefulness of the arterial stiffness index (ASI) measured non-invasively by computerized oscillometry and by comparing it with the pulse wave velocity (PWV). METHODS AND RESULTS: The study group comprised 60 consutive patients who underwent coronary angiography and whose aorto-femoral PWV were obtained with a Judkins catheter. The ASI was obtained using Cardio Vision MS-2000 (IMDP, Las Vegas, NV, USA): (i) baseline (ASI-B); (ii) hyperemia induced by compression of the arm with cuff pressure for 5 min (ASI-H); and (iii) sublingual nitroglycerin (ASI-N). In total, 34 patients had significant coronary artery disease (CAD). The PWV and all ASI were higher in patients with CAD than in those without CAD (ASI-B, 85.9+/-57.8 vs 48.2+/-24.5, p=0.001; ASI-H, 98.1+/-49.8 vs 48.1+/-21.3, p<0.01; ASI-N, 66.7+/-55.7 vs 33.2+/-27.9, p=0.002). However, only ASI-B and ASI-H were positively correlated to the PWV (ASI-B, r=0.27, p=0.03; ASI-H, r=0.49, p=0.001; ASI-N, r=0.19, p=0.16). The ASI was increased after hyperemia in patients with CAD (ASI-H, 85.9+/-57.8 to 98.1+/-49.8, p=0.01), but not in patients without CAD (ASI-H, 48.2+/-24.5 to 48.1+/-21.3, p>0.01). After adjusting their age, only ASI-H was correlated to the presence of CAD (r=0.33, p<0.01). CONCLUSIONS: It is feasible and useful to use the ASI for detection of atherosclerotic coronary disease. The findings of ASI-H suggests that in addition to stiffening of the arterial wall itself, the impairment of flow mediated vasodilation, because of endothelial dysfunction, further increases the arterial stiffness.

Adult↗