Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “RESPIRATORY SYSTEM”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 325 records · Page 18Linked to original sources
PubMed1997

The effect of isoflurane, halothane, sevoflurane, and thiopental/nitrous oxide on respiratory system resistance after tracheal intubation.

BACKGROUND: After tracheal intubation, lung resistance and therefore respiratory system resistance (R[rs]) routinely increase, sometimes to the point of clinical bronchospasm. Volatile anesthetics generally have been considered to be effective bronchodilators, although there are few human data comparing the efficacy of available agents. This study compared the bronchodilating efficacy of four anesthetic maintenance regimens: 1.1 minimum alveolar concentration (MAC) end-tidal sevoflurane, isoflurane or halothane, and thiopental/nitrous oxide. METHODS: Sixty-six patients underwent tracheal intubation after administration of 2 microg/kg fentanyl, 5 mg/kg thiopental, and 1 mg/kg succinylcholine. Vecuronium or pancuronium (0.1 mg/kg) was then given to ensure paralysis during the rest of the study. Postintubation R(rs) was measured using the isovolume technique. Maintenance anesthesia was then randomized to thiopental 0.25 mg x kg(-1) x min(-1) plus 50% nitrous oxide, or 1.1 MAC end-tidal isoflurane, halothane, or sevoflurane. The R(rs) was measured after 5 and 10 min of maintenance anesthesia. Data were expressed as means +/- SD. RESULTS: Maintenance with thiopental/nitrous oxide failed to decrease R(rs), whereas all three volatile anesthetics significantly decreased R(rs) at 5 min with little further improvement at 10 min. Sevoflurane decreased R(rs) more than either halothane or isoflurane (P < 0.05; 58 +/- 14% of the postintubation R(rs) vs. 69 +/- 20% and 75 +/- 13%, respectively). CONCLUSIONS: After tracheal intubation in persons without asthma, sevoflurane decreased R(rs) as much or more than isoflurane or halothane did during a 10-min exposure at 1.1 MAC.

Adult↗
PubMed1987

Total respiratory system compliance in asymptomatic infants with cystic fibrosis.

Total respiratory system compliance (Crs) was assessed by the weighted spirometer method in 11 asymptomatic infants (mean age, 11.1 months) with cystic fibrosis (CF) who had normal chest radiographs. In addition to Crs, functional residual capacity (FRC), respiratory rate (RR), and mixing index (MI) were measured. There was no significant difference in FRC between normal controls (n = 36) and CF infants (190 +/- 69 versus 186 +/- 63 ml; p less than 0.8), although the CF group had a higher RR (32 +/- 7 versus 37 +/- 7 BPM; p less than 0.05) and a lower MI (45 +/- 7 versus 40 +/- 8%; p less than 0.05), reflecting an abnormal distribution of ventilation. The lower Crs (9.0 +/- 3.4 versus 5.7 +/- 2.8 ml/cm H2O; p less than 0.01) and the lower specific compliance, Crs/FRC (0.049 +/- 0.013 versus 0.029 +/- 0.007 1/cm H2O; p less than 0.0001), in the CF group were the parameters that best distinguished the normal control and CF infants. We conclude that the measurement of Crs represents a noninvasive method for detecting early pulmonary function abnormalities in CF infants.

Cystic Fibrosis↗
PubMed1996

Total respiratory system, lung, and chest wall mechanics in sedated-paralyzed postoperative morbidly obese patients.

OBJECTIVE: To study the relative contribution of the lung and the chest wall on the total respiratory system mechanics, gas exchange, and work of breathing in sedated-paralyzed normal subjects and morbidly obese patients, in the postoperative period. SETTING: Policlinico Hospital, University of Milan, Italy. METHODS: In ten normal subjects (normal) and ten morbidly obese patients (obese), we partitioned the total respiratory mechanics (rs) into its lung (L) and chest wall (w) components using the esophageal balloon technique together with airway occlusion technique, during constant flow inflation. We measured, after abdominal surgery, static respiratory system compliance (Cst,rs), lung compliance (Cst,L), chest wall compliance (Cst,w), total lung (Rmax,L) and chest wall (Rmax,w) resistance. Rmax,L includes airway (Rmin,L) and "additional" lung resistance (DR,L). DR,L represents the component due to viscoelastic phenomena of the lung tissue and time constant inequalities (pendelluft). Functional residual capacity (FRC) was measured by helium dilution technique. RESULTS: We found that morbidly obese patients compared with normal subjects are characterized by the following: (1) reduced Cst,rs (p < 0.01), due to lower Cst,L (55.3 +/- 15.3 mL x cm H2O-1 vs 106.6 +/- 31.7 mL x cm H2O-1; p < 0.01) and Cst,w (112.4 +/- 47.4 mL x cm H2O-1 vs 190.7 +/- 45.1 mL x cm H2O-1; p < 0.01); (2) increased Rmin,L (4.7 +/- 3.1 mL x cm H2O x L-1 x s; vs 1.0 +/- 0.8 mL x cm H2O x L-1 x s; p < 0.01) and DR,L (4.9 +/- 2.6 mL x cm H2O x L-1 x s; vs 1.5 +/- 0.8 mL x cm H2O x L-1 x s; p < 0.01); (3) reduced FRC (0.665 +/- 0.191 L vs 1.691 +/- 0.325 L; p < 0.01); (4) increased work performed to inflate both the lung (0.91 +/- 0.25 J/L vs 0.34 +/- 0.08 J/L; p < 0.01) and the chest wall (0.39 +/- 0.13 J/L vs 0.18 +/- 0.04 J/L; p < 0.01); and (5) a reduced pulmonary oxygenation index (PaO2/PAO2 ratio). CONCLUSION: Sedated-paralyzed morbidly obese patients, compared with normal subjects, are characterized by marked derangements in lung and chest wall mechanics and reduced lung volume after abdominal surgery. These alterations may account for impaired arterial oxygenation in the postoperative period.

Abdomen↗
PubMed1963

Respiratory systems in the hemin-requiring Haemophilus species.

White, D. C. (Rockefeller Institute, New York, N.Y.). Respiratory systems in hemin-requiring Haemophilus species. J. Bacteriol. 85:84-96. 1963.-If grown in Levinthal's medium or in proteose peptone medium with excess hemin, Haemophilus influenzae, H. aegyptius, and H. canis (H. haemoglobinophilus) form an electron-transport system consisting of six cytochromes and two respiratory flavoproteins. In proteose peptone, these species can greatly modify the composition of their electron-transport complex. With anaerobic incubation in the presence of nitrate, they produce increased amounts of cytochrome c(1) and the cytochrome oxidases a(1) and o. This anaerobic pattern is greatly exaggerated by growth under carbon monoxide, in which case large concentrations of cytochrome oxidase are produced. In the presence of the inhibitor secobarbital or of growth-limiting amounts of hemin, intermediate amounts of cytochromes and respiratory flavoproteins are formed. When only small amounts of hemin are present, these species grow but form no detectable cytochrome system. Catalase is the only hemoprotein found. Under these conditions, the addition of glucose induces the formation of a lactate oxidase flavoprotein if the system is incubated aerobically. This cytochromeless state also occurs when these species are grown in KCN or anaerobically without nitrate and with excess hemin. The ability of these species to modify the composition of the electron-transport system strongly suggests that this function unit is formed from individual components. Hemin-requiring Haemophilus species have a hemin-sparing compensatory mechanism that allows growth under conditions under which hemin-independent Haemophilus species will not grow.

Catalase↗
PubMed1989

Mechanics of the respiratory system during passive exhalation in preterm lambs.

Previous studies have shown large inhomogeneities in the distributions of ventilation and perfusion of newborn infants with hyaline membrane disease. The purpose of this study was to show that measurements of lung mechanics also show evidence of lung inhomogeneities and that a multiple compartment analysis of mechanics gives a more accurate representation of passive exhalation flow and volume than single valued mechanics. We studied 10 sedated preterm lambs (130 d gestation) weighing 2.2 +/- 0.3 kg at 4 h postnatal age. Passive exhalation lung mechanics of the respiratory system were measured by obstructing gas flow near end inhalation then, after pressures within the lung reached equilibrium, allowing the animals to exhale to the atmosphere. Airway pressure and flow signals were monitored by a computer then analyzed using single and multiple compartment analyses. Single compartment analysis of time constant (tau) in s, respiratory system resistance (R) in cm H2O/L/s and quasistatic compliance (C) in mL/cm H2O yielded tau = 0.16 +/- 0.07, R = 92 +/- 17, and C = 1.8 +/- 1.1 (mean +/- SD). Multiple compartment analysis yielded "fast compartment" tau 1 = 0.10 +/- 0.04, R1 = 90 +/- 28, and C1 = 1.1 +/- 0.5 and "slow compartment" tau 2 = 0.25 +/- 0.12, R2 = 503 +/- 288, and C2 = 0.7 +/- 0.6. All of the animals studied exhibited nonlinearity in their flow-volume plots. Calculated flow-volume plots were much more accurately portrayed by the two-compartment analysis than by single valued mechanics. Multiple compartment analysis of lung mechanics may provide useful insight into the pathophysiology of the preterm lab with hyaline membrane disease.

Animals↗
PubMed2006

[Types of physiological reactivity of the respiratory system and the features of physical work capacity in athletes].

On the basis researches of character responses of respiratory system (RS) on hypercapnic and physical load at 54 skilled athletes (the runners on 100, 800 and 5000 m) are analyzed of the features in physiological reactivity of system on shifts respiratory homeostasis, reflecting a various orientation of long-term adaptation (sports of the training). The interrelation of sensitivity and stability of responses to hypercapnic (CO2-H+), and also limits and kinetic characteristics of responses RS of physical loads with manifestation of work capacity and mobilization features aerobic and anaerobic processes of during physical loads energy-supply was demonstrated. By means of tacsonomic analyses are allocated types of individual responses of organism of the skilled athletes on the basis of character RS responses to hypercapnic shifts in respiratory homeostasis. They in a high degree have been caused by sports specialization of athletes.

Adult↗
PubMed1999

[Effect of ammonia on the pig respiratory system. Study of the dose-response relation].

The effects of ammonia on the respiratory system and somatic growth have been measured in piglets taking into account the interactions with endotoxins from gram-bacteria and dust. Dose-response curves were constructed for the inflammatory reactions induced in nasal cavities, the smooth muscle hyperresponsiveness in the trachea, the permeability of alveolo-capillary barrier, the pulmonary vasomotricity, the cough reflex and the systemic effects. An acceptable level of pollution was proposed.

Air Pollutants↗
PubMed1996

Physiology of respiratory system related to anesthesia.

All inhalational anesthetic agents depress respiratory function. They also depend largely on the respiratory system to facilitate an induction and emergence from anesthesia. The other anesthetic agents, such as intravenous agents, also depress respiration. Much of the morbidity and mortality that occurs in the perioperative period can be attributed to an alteration in lung mechanics and dysfunctions in airway dynamics. In fact, it is postulated that 70% to 80% of the morbidity and mortality occurring in the perioperative period is associated with some form of respiratory dysfunction. Consequently, a detailed discussion of the many facets of respiratory anatomy and physiology will be presented. If the CRNA incorporates this information into anesthesia practice, care of the surgical patient will be enhanced.

Anesthesia, Inhalation↗
PubMedDate not supplied

[Effect of inhalation of hair spray on the rat respiratory system].

A study of the effects of inhaled hair-spray was performed on 118 specific pathogen free male Wistar rats (71 test animals and 47 controls). Rats were exposed for 5 min, three times a day, five days per week, during one to eight weeks, in two plexiglas chambers, one for controls and one for test animals. The chambers were 20 1 in size, but only the noses of the animals were exposed to ambiant air or to a hair-spray aerosol polluted atmosphere. In the test chamber, the hair-spray was aerosolized for 30 s at the beginning of each exposure, using about 30 g of nebulized product. This hair-spray amount was high, although non-lethal (70% of DL0, 45% of DL50 and 26% of DL100). The hair-spray exposed rats exhibited significant modifications in the antixenic defence mechanisms of their respiratory system: diminished ciliary activity of the tracheal epithelium (-26%), increased number of harvested pulmonary macrophages (+52%), but decreased phagocytic ability of these cells (-8%). However we did not observe histologic differences in the respiratory system of exposed and control rats.

Aerosols↗
PubMed2006

Vibration and its effect on the respiratory system.

Vibration is a manual technique used widely to assist with the removal of pulmonary secretions. Little is known about how vibration is applied or its effect on the respiratory system. The purpose of this study was to describe mechanical consequences of vibration on the chest wall of a normal subject and the effects of vibration on expiratory flow rates and volumes. The effects of vibration were compared to other interventions of chest wall compression, chest wall oscillation, cough, huff from high lung volume, inspiration to total lung capacity with relaxed expiration, tidal breathing, and sham. Sixteen physiotherapists applied vibration and other interventions in a randomised order to the chest wall of a healthy adult female subject. The magnitude and direction of the force and the frequency of vibration were measured by an instrumented bed with seven load cells. Inductive plethsysmography measured the change in chest wall circumference with vibration. A heated pneumotachometer measured inspiratory and expiratory flow rates, which were integrated to provide volumes. Vibration was applied with a mean resultant force of 74.4 N (SD 47.1). The mean (SD) change in chest wall circumference and frequency of vibration were 0.8 cm (SD 0.4) and 5.5 Hz (SD 0.8) respectively. The mean peak expiratory flow rate was 0.97 l/s (SD 0.27). Peak expiratory flow rates with vibration were less than 20% of those achieved with cough or huff from high lung volume but greater than with chest wall compression, chest wall oscillation, relaxed expiration from total lung capacity, sham treatment or tidal breathing.

Adult↗
PubMed1994

[Analysis of the characteristics of human papilloma virus infection in 85 neoplasms of the respiratory system in adult patients].

Eighty five neoplastic tissues of respiratory system in Chinese adult patients were searched for HPV by multiple PCR and in situ hybridization. In 13 of the specimens examined, HPV DNA was identified (15.3%), including 6 of 36 cases of pharyngolaryngeal neoplasms (16.6%) and 7 of 49 cases of lung squamous cell carcinomas (14.2%). Among the 13 cases tumor specimen, most of them were positive for HPV6/11 types and a few were double positive for HPV 6/11 and 16 types. Many tumor cells positive for HPV DNA on in situ hybridization were morphologically similar to those koilocytes in genital condylomas. HPV infection in 85 neoplasms was characterized by the fact that the same genotypes of HPV were detected in upper and lower respiratory tract and that the dominant virus types detected were HPV 6/11 types. The detection rate of HPV was a little higher in the upper than that in the lower respiratory tract and the HPV DNA positive tumors had similar histological appearance. The results suggest that HPV infection in the neoplasms of the upper and the lower airways is related to each other with similar mode of transmission.

Carcinoma, Squamous Cell↗
PubMed2001

Static compliance of the respiratory system in healthy infants.

We recorded static deflation pressure-volume (PV) curves from near TLC to FRC in 49 healthy, sedated, spontaneously breathing infants of 1 to 104 wk of age. Respiratory activity was transiently inhibited by inflating the respiratory system several times to a volume at an airway pressure of 30 cm H2O (V30). Passive deflation from V30 to FRC was then interrupted by multiple brief occlusions at the airway opening, in order to measure static recoil pressures. The expired volume from V30 to FRC was defined as V30E. Compliance of the respiratory system (Crs) was calculated as the slope of the linear portion of the PV curve from 5 to 15 cm H2O. Crs and V30E increased with increasing body length (p < 0.001). After adjustment for body length, males had greater Crs values than did females (p < 0.01). V30E was smaller in female infants (p < 0.05) and in infants whose mothers smoked during pregnancy (p < 0.04). Specific compliance (Crs/V30E) declined with increasing age (p < 0.01), but there were no differences related to sex or maternal smoking. We conclude that static deflation PV curves can be recorded in the age range from 1 to 104 wk, and that maternal smoking may produce hypoplastic lungs.

Child, Preschool↗
PubMed1994

Monitoring the respiratory system of the mechanically ventilated patient.

Bedside monitoring of respiratory status is designed to measure specific parameters and alert the clinician when these parameters exceed the limits of a desired range. Parameters should include measures of respiratory mechanics, oxygenation, and ventilation. Monitoring is the only form of communication between the physician and a patient receiving neuromuscular blocking agents. Airway pressure tracing alone, or in conjunction with concurrent flow, measures respiratory system mechanics, resistance, compliance, and the work of breathing. Pulse oximetry reflects oxygenation, while mixed venous oximetry indicates the balance between oxygen supply and demand. Capnography is a noninvasive way of assessing ventilation. Taken as a whole, noninvasive monitoring provides useful information, reflecting trends in oxygenation, ventilation, and mechanics. This article reviews the concepts of noninvasive monitoring of critically ill patients. Emphasis is given to the patient receiving neuromuscular blocking agents.

Airway Resistance↗