Effects of terbutaline sulphate aerosol on bronchodilator response and lung mucociliary clearance in patients with mild stable asthma

Ventilatory function and whole lung mucociliary clearance have been assessed in 10 patients with mild stable asthma following inhalation of 1 mg of the beta-adrenergic receptor agonist terbutaline sulphate (Bricanyl, Astra Pharmaceuticals) from a metered dose inhaler (MDI). Compared to placebo inhalation, terbutaline produced marked bronchodilatation (mean percentage increase in FEV1 14%, P less than 0.01). Mucociliary clearance (measured by the in vivo radioaerosol technique) was assessed on three occasions--control, followed by placebo or terbutaline studies in a double-blind, cross-over manner. Particles were removed from the lung at a similar rate in all three studies. The mean (+/- s.e. mean) percentage of aerosol retained in the lungs after 6 h was 58 +/- 5%, 57% +/- 5% and 57 +/- 4% for control, placebo and drug studies respectively. It is concluded that terbutaline sulphate, given as a 1 mg acute dose, does not enhance mucociliary clearance in mild stable asthmatics, although it produces marked bronchodilatation.

Assessment of the forced expiration technique, postural drainage and directed coughing in chest physiotherapy

The Forced Expiration Technique (FET), postural drainage (PD) and directed coughing have been evaluated in 10 patients with copious sputum (mean value 63.3 ml/24 h) with an inhaled radioaerosol method over a 30-min treatment period. FET alone and FET + PD (but not directed coughing) cleared more radioaerosol than during the control period (P less than 0.01). The wet weight of sputum obtained following FET, FET + PD and directed coughing were all significantly greater than control (P less than 0.01). However, sputum obtained by FET + PD was significantly greater than FET alone (P less than 0.05). Both FET and particularly FET + PD have been shown to be more effective than directed coughing alone and it is suggested that these manoeuvres should be incorporated into standard chest physiotherapy.

Inhaled aerosols: lung deposition and clinical applications

Although aerosol deposition in the lungs is often considered in the context of industrial hygiene, aerosols also play an important clinical role. Three principal mechanisms (inertial impaction, gravitational sedimentation and Brownian diffusion) account for the majority of aerosol deposition in the lungs. Deposition depends upon the mode of inhalation, the nature of the particles and physical characteristics of the subject inhaling the particles. Radioaerosols are widely employed in measurements of total and regional deposition, and topographical distribution may also be determined. Aerosols play an important role in the treatment of various forms of respiratory disease, with bronchodilators for the therapy of asthma being particularly important. On average only 10% of the therapeutic aerosol dose actually reaches the lungs. The rate of removal of insoluble radioaerosols deposited in the lungs may be used as an index of mucociliary transport. Aerosols are also used in a variety of other diagnostic and research procedures, particularly for ventilation scanning, alveolar clearance, measurement of alveolar permeability, and for measuring the size of pulmonary air space.

Is cough as effective as chest physiotherapy in the removal of excessive tracheobronchial secretions?

The relative value of chest physiotherapy (including cough) and cough alone for the removal of excessive tracheobronchial secretions has been assessed in six patients with stable chronic obstructive lung disease. After labelling with inhaled radioactive tracer particles, clearance of secretions from selected central and peripheral lung regions was followed with a gamma camera linked to a computer. Cough alone and chest physiotherapy (including cough) were equally effective in the enhancement of central lung clearance. Physiotherapy but not cough along accelerated peripheral lung clearance (p less than 0.05). Sputum yield was greater during physiotherapy than during cough (p less than 0.05). These findings confirm the value of chest physiotherapy and high-light the limitation of cough in patients with excessive tracheobronchial secretion and impaired mucociliary clearance.

Deposition of pressurized suspension aerosols inhaled through extension devices

Only a small fraction of the dose from a pressurized aerosol inhaler reaches the lung, because most is deposited on the upper airways by inertial impaction. We have investigated the effects on aerosol deposition of two spacer devices (a 10-cm tube and a 22-cm cone) by incorporating teflon particles (mass median aerodynamic diameter, 3.2 micrometer) labeled with 99mTc into pressurized canisters. Ten subjects with obstructive airway disease inhaled the aerosol in a controlled manner from a conventional actuator alone or in combination with the tube or the cone. Radioaerosol distribution was measured using a shadowshield whole body counter. Deposition on the conducting airways was significantly improved by both spacers, but alveolar deposition was unchanged. Initial oropharyngeal deposition was reduced by both spacers in all 10 patients. We conclude that the spacer devices may have a role to play in aerosol therapy by increasing drug availability to the lung, while at the same time decreasing unwanted drug deposition in the oropharynx.

How should a pressurized beta-adrenergic bronchodilator be inhaled?

Although the manufacturers of pressurized aerosol bronchodilators issue instructions for using the inhalers, little or no experimental verification exists. Furthermore, the instructions often fail to take into account known facts about aerosol deposition. We have reviewed the evidence for the most effective mode or modes of inhalation of pressurized aerosol bronchodilators, some of which has arisen from experiments performed in our laboratory. In order to achieve a maximal effect following inhalation of terbutaline sulphate bronchodilator aerosol (Bricanyl, Astra Pharmaceuticals), the canister should be actuated during a slow (25 l min-1), deep inhalation and breath held subsequently for 10 s. Bronchodilatation may be reduced if aerosol is inhaled rapidly (80 l min-1) or if breath is held for 4 s. We have considered the applicability of these simple rules to other types of bronchodilator and to all patients, irrespective of their diagnosis or degree of airway obstruction. The lung volume at which aerosol is released into the airstream, the importance of coordinating inhalation with aerosol actuation, and the relative merits of "open" and "closed" mouth inhalation techniques are also discussed.

Comparison of radioisotope methods for the measurement of phosphate absorption in normal subjects and in patients with chronic renal failure

1. Intestinal phosphate absorption was measured in normal subjects, in patients with chronic renal failure, and in post-transplant patients, by a double isotope technique involving oral administration of 32P and simultaneous intravenous injection of 33P with subsequent deconvolution analysis. 2. By this technique intestinal phosphate absorption has been shown to have two components: an initial rapid phase, which is completed by 3 h, and a slower more prolonged phase, which continues beyond 7 1/2 h. 3. Phosphate malabsorption has been demonstrated in chronic renal failure and transplant patients, which is accounted for by impairment of the initial rapid phase of absorption. 4. Results obtained by deconvolution analysis have been compared with other estimates of phosphate absorption obtained from analysis of 32P radioactivity curves alone. 5. The fractional hourly rate of absorption and the plasma 32P radioactivity at 60 min corrected for extracellular fluid volume provided the best approximations to the result obtained by deconvolution analysis, with respect to both the maximal rate of phosphate absorption and cumulative percentage phosphate absorption.

Deposition of pressurised aerosols in the human respiratory tract

Although the use of pressurised aerosol inhalers is widespread, little is known about the actual deposition of the aerosol in the respiratory tract, since this has previously been difficult to measure. We have incorporated Teflon particles (mean diameter 2 micrometer) with aerodynamic properties similar to those of bronchodilator drug crystals into pressurised aerosol canisters. Controlled inhalations by eight patients with obstructive airways disease showed that on average 8.8% of the dose was deposited in the lungs (3.0% in the alveoli and 5.8% on the conducting airways) and 80% in the mouth. These figures are in good agreement with previous indirect estimates of deposition based on metabolic studies. The remainder of the dose was either expired (1.0%) or deposited in the aerosol actuator (9.8%). This method should have wide application for measurement of deposition patterns under various conditions and for assessment of therapeutic effects.

Observations on copper associated protein in childhood liver disease

Hepatic copper concentrations were compared with staining grades of copper associated protein (CAP) and histochemical copper in liver sections from 44 patients (one fetus, one pre-term infant, four term infants, eight normal children, 16 children with various liver diseases, and 14 patients with intrahepatic cholestasis of childhood (IHCC)). A similar comparative study of hepatic copper concentration with CAP and histochemical copper was performed in 21 patients with Wilson's disease. CAP occurred in the fetus, pre-term infant, and term infants without liver disease. This suggests that CAP is a normal constituent of the hepatocyte and is not a consequence of liver disease or biliary obstruction. CAP was not seen when hepatic copper concentration was normal; it was absent in eight children with no evidence of liver disease, eight children with non-cirrhotic liver disease, and seven of eight children with cirrhosis. When hepatic copper concentration exceeded 4.0 mumol/g dry liver weight grade 2 or grade 3 staining for CAP and histochemical copper was found in the fetus, pre-term infant, infants, and IHCC. CAP was found in IHCC only in the presence of raised hepatic copper levels, supporting evidence of a relationship between copper and CAP. In 17 of 21 patients with Wilson's disease hepatic copper concentrations exceeded 4 mumol/g. Positive staining for CAP was seen in seven of these patients being usually grade 1. CAP is a normal associated protein, present when hepatic copper concentrations are increased in normal liver cells. It is usually absent in hepatocytes from Wilson's disease despite similar hepatic copper levels. CAP may represent material which protects the hepatocyte from the toxic effects of copper.

Effect of oral 1,25 dihydroxycholecalciferol on calcium and phosphate malabsorption in primary biliary cirrhosis

Changes in calcium and phosphate absorption in response to treatment with small doses of oral 1,25 (OH)2D3 were studied in 10 patients with primary biliary cirrhosis by means of a combined radio-isotope technique. There was a marked improvement in the fractional rates of absorption of calcium (P less than 0.01) and phosphate (0.05 P less than 0.1) after treatment. This implies than there is no end organ unresponsiveness to the action of active Vitamin D metabolites at the intestinal level in primary biliary cirrhosis.

Dissociation of absorptions of calcium and phosphate after successful cadaveric renal transplantation

Calcium and phosphate absorptions were studied by radiotracer techniques in 30 patients after successful cadaveric renal transplantation, and results were compared with those in a group of normal subjects and in groups of patients with chronic renal failure (CRF). Both calcium and phosphate absorptions were impared in patients with CRF, including those receiving haemodialysis. Abnormalities of calcium absorption, however, seemed to occur earlier in the course of advanced renal failure than abnormalities in phosphate absorption. Calcium absorption improved dramatically after successful renal transplantation, while phosphate absorption remained the same. A dissociation between calcium and phosphate absorptions is not often seen clinically, and the mechanisms for it are unknown. Phosphate malabsorption may be a further contributing factor in the development of persistent hypophosphataemia after transplantation.

Regional lung clearance of excessive bronchial secretions during chest physiotherapy in patients with stable chronic airways obstruction

Clearance of excessive bronchial secretions labelled with inhaled radioactive polystyrene particles has been directly measured with a gamma-camera linked to a computer. Chest physiotherapy significantly increased clearance from central, intermediate, and peripheral lung regions and sputum yield. These findings confirm the value of this form of treatment, which has hitherto been in doubt, in removing excessive bronchial secretions from all lung regions and in aiding their expectoration.

Histological demonstration of copper and copper-associated protein in chronic liver diseases

Liver copper concentrations in percutaneous biopsy specimens were measured by neutron activation analysis and compared with histological staining for copper by rubeanic acid and rhodanine, and with copper-associated protein stained by orcein. Liver copper concentrations were elevated in 31 of 35 biopsies from patients with primary biliary cirrhosis (PBC), and discrimination between normal and elevated liver copper was correct in 32 of the 35 biopsies by staining with rubeanic acid, and 31 of the 35 by staining with rhodanine. Orcein staining of copper-associated protein was positive in 33 of the 35 biopsies. All 17 biopsy specimens from patients with Wilson's disease had high liver copper concentrations, but only nine had positive staining for copper, and six were orcein positive. Similarly, histological stains gave little indication of the liver copper concentrations in tissue from 16 patients with chronic active hepatitis. Staining of liver sections can be useful in detecting elevation of liver copper in PBC, but not in Wilson's disease, where the absolute concentration must be measured. Excess copper appears to accumulate in the liver in different chemical forms in PBC and Wilson's disease.

Impaired cardiovascular responsiveness in liver disease

Cardiovascular responsiveness to reflex impaired in patients with cirrhosis compared with control subjects. Peripheral vascular responses to exogenous noradrenaline were also impaired in cirrhotic patients, but peripheral vascular responses to infused adrenaline and to angiotensin II were similar in both groups. Impaired cardiovascular reactivity in patients with chronic liver disease could predispose them to circulatory failure after haemorrhage or surgery and should be considered when prescribing drugs which affect autonomic activity.

Enhancement of renal blood flow in transplanted dog kidneys following perfusion with frusemide

Frusemide was added to the perfusate used to flush kidneys prior to transplantation. The 133Xe wash-out technique was used to measure renal blood flows before and after transplantation and the clearance curves were analysed into cortical and medullary components. It is concluded that the addition of frusemide to the perfusate contributes significantly to the restoration of a satisfactory blood flow to a transplanted kidney.

Skeletal muscle blood flow and neurovascular reactivity in liver disease

There was no significant difference in forearm muscle blood flow, measured by the clearance of (133)Xenon when 38 patients with liver disease were compared with 38 normal subjects. Patients with a clinically hyperdynamic circulation, finger clubbing, and previous portocaval anastomoses were included in the study. The changes in forearm skeletal muscle blood flow and pulse rate caused by a head-up tilt of 70 degrees were measured in 15 patients with chronic liver disease and 15 age-matched controls. Head-up tilting resulted in significantly less peripheral vasoconstriction and tachycardia in the group with liver disease than in the control group. These results suggest an impairment of baroreceptor-mediated sympathetic reactivity in liver disease. Such a defect might explain the relative rarity of hypertension in patients with cirrhosis.