Pulmonary vascular permeability to transferrin in the pulmonary oedema of renal failure

Evaluation of alveolar permeability and lung ventilation in patients with chronic renal failure using Tc-99m DTPA radioaerosol inhalation lung scintigraphy

Lung ventilation (LV) and alveolar permeability (AP) were measured in 24 male chronic renal failure (CRF) patients on regular hemodialysis (HD). LV and AP were determined by Tc-99m DTPA aerosol inhalation lung scintigraphy using commercial lung radioaerosol delivery units. The equilibrium LV images were visually interpreted by two independent and experienced nuclear medicine physicians. The degree of AP damage to the total right lung was presented as the clearance rate (k value; %/min) of the time-activity curve from dynamic total right lung images. The results showed 10/24 (42%) cases with inhomogeneous distribution and 8/24 (33%) cases with hypoventilation on equilibrium LV images. In comparison with 10 male normal controls, the k value of the CRF patient group was larger (1.14 +/- 0.36%/min vs 0.75 +/- 0.14%/min, p value < 0.05). In addition, there was no significant correlation for k value and albumin level (r2 = 0.008) or for k value and HD duration (r2 = 0.228). In conclusion, CRF can predispose patients to LV change and AP damage. However, the degree of AP damage is not related to serum albumin level or HD duration.

Evaluating the changes in alveolar permeability and lung ventilation in patients with chronic renal failure after haemodialysis using 99mTc-DTPA radioaerosol inhalation lung scan

Hypoxaemia occurring in patients with chronic renal failure (CRF) during haemodialysis (HD) has long been known. Several mechanisms of pathogenesis have been proposed. Before and after regular HD, lung ventilation (LV) and alveolar permeability (AP) were measured in 24 male patients with CRF (age, 61-75 years). LV and AP were determined by 99mTc-diethylenetriaminepentaacetic acid (99mTc-DTPA) radioaerosol inhalation lung scan (99mTc-DTPA lung scan). The LV images were visually interpreted according to established criteria, including the presence or absence of an inhomogeneous distribution, inverted base to apex gradient and segmental hypoventilation. The degree of AP in the total right lung was presented as the clearance rate (K; %.min-1) of the time-activity curve from dynamic total right lung images. Ten male normal controls (age, 62-76 years) were enrolled in the study for comparison. Ten of 24 (42%) cases showed an inhomogeneous distribution and eight of 24 (33%) cases showed hypoventilation on equilibrium LV images. After regular HD for 5 h, no significant changes in the LV images were found. Before HD, the CRF patient group (K=1.14+/-0.36%.min-1) had a significantly faster clearance rate than that of normal controls (0.75+/-0.14%.min-1, P<0.05). Moreover, the clearance rate after HD was significantly slower (0.87+/-0.15%.min-1, P<0.05) than that before HD. CRF can predispose patients to LV change and AP damage. After HD, the damage to AP is significantly improved. However, after HD, the change in LV is not significant.

Pulmonary nuclear medicine

This article reviews the contribution made by nuclear imaging to the assessment, diagnosis and monitoring of patients with respiratory disease. It focuses on several specific areas including the diagnosis of pulmonary embolism, the investigation of intrapulmonary infection and neoplasm and the role of positron emission tomography (PET) scanning.

External detection of pulmonary accumulation of indium-113m labelled transferrin in the guinea pig

Accumulation of radioisotope labelled transferrin in the lungs of guinea pigs was determined with an external detection system. The method is based on the intravascular and extravascular distribution of indium-113m labelled transferrin compared with the intravascular distribution of technetium-99m labelled red blood cells. Guinea pigs were given iloprost, a prostacyclin analogue and potent pulmonary vasodilator, and noradrenaline, a pulmonary vasoconstrictor, in an attempt to increase and decrease respectively the blood volume in the lungs. Neither agent altered transferrin accumulation in the lung by comparison with a saline infusion. Iloprost infused before and after oleic acid infusion reduced macro-molecular leakage when compared with oleic acid alone. These data suggest that the double isotope method can distinguish between hydrostatic and injury induced pulmonary oedema.

Fluid requirements of patients with burns and inhalation injuries in an intensive care unit

We have studied 9 patients with burns (20%-75%) who had inhalation injuries and compared their actual fluid requirements with their requirements calculated from the Muir and Barclay formula. All patients were resuscitated with plasma protein fraction at a rate sufficient to keep their physiological variables within the following range: heart rate less than 120/min, central venous pressure 8-12 cm H2O, urine output greater than 30-50 ml/h, systolic blood pressure greater than 90 mm Hg and diastolic blood pressure greater than 60 mm Hg. The amount of plasma protein fraction needed was 4.38 +/- 1.26 ml/kg/% burn in the first 24 h and 2.15 +/- 0.97 ml/kg/% burn in the second 24 h. This is an increase of 75% and 110% respectively above values predicted from the formula. We suggest that the observed difference is due to a combination of the presence of an inhalation injury which increases fluid requirements by approximately 30% in the first 24 h and the use of plasma protein fraction rather than the dried plasma used in the original Muir and Barclay formula.

The radiographic differentiation of pulmonary oedema

A radiographic scoring system has been reported to have a high diagnostic accuracy in the differentiation of pulmonary oedema of renal, cardiac and capillary origin. In the present study, a similar scoring system was used in 51 patients with radiographic appearances of pulmonary oedema due to renal failure (n = 16), cardiac failure (n = 13) and to adult respiratory distress syndrome (ARDS) (n = 22). Evidence of increased pulmonary capillary permeability to transferrin was sought in all patients using a double-isotope method to derive a protein accumulation index (PAI). Using the clinical diagnosis of each type of pulmonary oedema as the "gold standard", sensitivity, specificity and accuracy for the chest radiographic scoring system in pulmonary oedema of cardiac origin were 46, 84 and 75%, respectively. For renal patients these values were 63, 86 and 78% and for ARDS, 89, 33 and 77%. For the PAI in ARDS, sensitivity was 85%, specificity 67% and accuracy 86%. The radiographic scoring system failed to distinguish between pulmonary oedema of renal and cardiac origin and cannot be considered of diagnostic value, but it was more successful in assessment of ARDS. Radiographic appearances suggestive of capillary injury and increased capillary permeability to transferrin occurred in all groups and such findings are not specific to ARDS as currently defined.

Diagnostic criteria for adult respiratory distress syndrome: time for reappraisal

To assess whether current diagnostic criteria for the adult respiratory distress syndrome (ARDS) may limit research to patients with a range of severity of respiratory failure and risk factors for ARDS were studied. In 28 patients ARDS did not develop; in 9 it did; and the other 13 met the diagnostic criteria at their first assessment. Plasma concentration of neutrophil elastase-alpha 1-antitrypsin complex was higher in all groups than in controls. For all patients, plasma elastase-complex was related to worsening hypoxia and to increased bronchoalveolar lavage protein content. Elastase-complex was present in all bronchoalveolar lavage samples and was related to protein content and differential neutrophil counts. Patients at risk of or with ARDS had a spectrum of respiratory failure to which intravascular and intra-alveolar neutrophil elastase release and capillary permeability were related. This suggests that the state recognised as ARDS is not a distinct pathophysiological entity.

Neutrophil degranulation and increased pulmonary capillary permeability following oesophagectomy: a model of early lung injury in man

In nine subjects undergoing oesophagectomy a transient but significant increase in pulmonary vascular permeability to transferrin was detected in both lungs 8 h after surgery. It coincided with a significant increase in plasma lactoferrin, evidence of intravascular and intra-alveolar neutrophil elastase release and with arterial hypoxaemia. The postoperative state in these patients had intravascular and pulmonary features often associated with the adult respiratory distress syndrome, and might be a useful model for the study of the early inflammatory events underlying lung injury in man.