Water In Dogs Research Articles

Measurement of extravascular lung water in patients with pulmonary edema

measurement of extravascular lung water has been a topic of major interest for more than two decades ([1][1], [5][2], [19][3]). In the recent article by Effros et al. ([2][4]), they provide a review of current and past efforts to measure extravascular lung water with thermal and osmotic dilution

Effect of pneumonectomy on extravascular lung water in dogs

The effect of pneumonectomy in dogs on extravascular lung water (EVLW) was studied using a double-indicator (iced indocyanine green dye) dilution technique. The EVLW was measured in five dogs before and after a left pneumonectomy while left atrial pressure was increased in 5-mm Hg increments from 10 to 25 mm Hg by serially inflating a left atrial Foley balloon. There were no significant differences in hematocrit, total protein, or plasma oncotic pressure before or after pneumonectomy. Prepneumonectomy EVLW was adjusted to reflect right lung EVLW alone. Both before and after pneumonectomy there was a significant increase in EVLW when left atrial pressure was increased to 25 mm Hg. However, EVLW values were similar before and after pneumonectomy at each level of left atrial pressure. We conclude that pneumonectomy does not acutely increase susceptibility to EVLW formation caused by a hemodynamic challenge. This implies that following pneumonectomy, if left heart filling pressures are normal, there is no clinical benefit to excessive fluid restriction.

Quantification of regional extravascular lung water in dogs with positron emission tomography, using constant infusion of 15O-labeled water.

Continuous infusion of 15O-labeled water allows a quantitative measurement of the total water pool in the chest region by positron emission tomography (PET). By subsequent inhalation of 11CO the intravascular space (blood pool) can be quantitated as well. After a suitable normalization of the intravascular activities the extravascular water can be determined by subtraction of the blood pool from the water pool. The regional extravascular lung water distribution can be visualized in tomographic slices. The method was validated in an animal experiment using five dogs. They were measured before and after induction of a lung edema by IV injection of oleic acid. The increase of extravascular lung water was monitored by the thermo-dye-dilution method (TDD). The correlation of extravascular lung water as measured by TDD with PET measurements is good (r = 0.94). The PET values agree also with gravimetric lung water determinations. An absolute quantitation of regional extravascular lung water is possible after absorption correction of the PET data via transmission measurements and calibration of the camera system. The uncertainty in the absolute quantification is +/- 20%. In the experiments described here the mean extravascular lung water was 0.13 g/cm3 before and 0.25 g/cm3 after induction of lung edema.

Quantitative measurements of regional extra-vascular lung water in dogs using positron emission tomography

A new method for quantifying regional variations in extravascular lung water (rELW) has been developed. The positron source 15O (T1/2 = 2.0 min.) was provided as H215O 'on line' by constant intravenous injection. Tomographic images (PET) of the water distribution were obtained during equilibrium. The distribution of blood volume was obtained by marking erythrocytes (carboxyhaemoglobin) using a bolus inhalation [C-11)-CO; T1/2 = 20.4 min). Absorption is calculated from transmission tomography. The rELW is defined as: total lung water minus intravascular space. The method was carried out in five intubated and anaesthetised dogs before and after induction of pulmonary oedema with oleic acid (0.06 ml./kg.). Mean ELW (PET) rose from 0.13 +/- 0.02 g./cm.3 to 0.24 +/- 0.04 g./cm.3. There was good correlation with a simultaneously performed thermo-dye method (7.1 +/- 1.3 ml./kg. KG to 13.3 +/- 1.9 ml./kg. KG; r = 0.94). Gravimetric estimations resulted in 13.7 +/- 2.6 ml./kg. KG. The development and distribution of the pulmonary oedema was non-homogeneous and varied regionally.

Measurement of extravascular lung water in dogs using the thermal-green dye indicator dilution method.

The measurement of extravascular lung water by a double-indicator dilution technique using cold indocyanine green dye was evaluated in dogs. Pulmonary edema was induced in 11 animals by volume overload; 12 animals served as controls. For each measurement, the two indicators (cold dye) were injected into the superior vena cava and detected in the femoral artery. The extravascular thermal volume was calculated using the mean transit times of the two indicator curves. Pretermination measurements of extravascular thermal volume correlated closely with standard gravimetric analysis of pulmonary extravascular tissue weight (EVTV - 1.15 PEW + 2.1 ml/kg, n = 21, r = 0.97, P less than 0.001; where EVTV = extravascular thermal volume and PEW = pulmonary extravascular tissue weight). Throughout the experiment, the arterial oxygen tension and alveolar-arterial oxygen tension gradient, correlated poorly with EVTV (linear correlation: r = 0.47, 0.45, respectively). The intrapulmonary shunt correlated better with EVTV (r = 0.72). Nonlinear correlation of EVTV with intravascular pressures (left ventricular filling pressures, colloid oncotic pressures, and the pulmonary artery occlusion pressure-colloid oncotic pressure gradient) were more significant than linear relationships. The critical pressures at which lung water rapidly increased in this model occurred at left ventricular filling pressures of 22-27 mmHg and at pulmonary artery occlusion pressure-colloid oncotic pressure gradients of 25-30 mmHg. The thermal dye technique appears to provide an accurate measurement of lung water changes in this pressure edema model.

The effect of barbiturates on 24-h water intake and renal excretion of sodium and water in dogs.

The effects of barbiturates on 24-h intakes of water and food and urinary excretion of sodium and potassium as well as on plasma concentration of sodium and potassium and osmolality were examined in dogs placed in metabolism cages and fed with a semiliquid diet. Administration of barbiturates stimulated drinking in a Series of 8 dogs having free access to water. Twenty four-h water intake and water balance increased significantly. Food intake, urinary output and urinary excretion of solutes, sodium and water did not change in this Series. A significant decrease in urine output as well as in osmolal clearance and urinary excretion of sodium was observed in a Series of 7 dogs having water restricted for 24 h following administration of barbiturates. Water balance increased in this Series. The same restriction of water in the dogs which had not received barbiturates did not modify renal excretion of water and electrolytes. Plasma osmolality, sodium and potassium concentrations did not change in either Series of experiments. It is concluded that barbiturates induce positive water balance either by stimulation of drinking when water is freely available or by reduction in urine output when water is restricted. The results suggest that expansion of the body fluids following the increased water intake may abolish reduction in urine output and sodium excretion which otherwise occur after administration of barbiturates.

Coronary capillary permeability and tissue volumes for sucrose and water in dogs: a comparison of bolus and constant infusion multiple-indicator methods

This study was undertaken to determine the accuracy with which heart interstitial and water volumes could be determined from multiple-indicator dilution experiments on the coronary circulation in open-chest dog preparations. Sucrose permeability by extraction calculations was found to average 0.26 +/- 0.02 cm3 . (min . g tissue)-1. The extravascular sucrose volume averaged 0.15 cm3 . g-1 tissue by both multiple-indicator and post-mortem methods. Indicator-dilution tritiated water curves labelled 85% of the post-mortem water content.

The relationship between right duct lymph flow and extravascular lung water in dogs given alpha-naphthylthiourea.

The relationship between right duct lymph flow and extravascular lung water was studied in 3 normal dogs and 15 dogs with pulmonary edema induced by alpha-naphthylthiourea (ANTU). Right duct lymph was collected in a pouch created by ligating jugular, subclavian, and brachiocephalic veins. Extravascular lung water was measured in vivo by double indicator dilution and post-mortem by weighting lungs before and after drying. Cardiac output, pulmonary artery and pulmonary artery wedge pressures, and the concentration of protein and electrolytes in plasma and right duct lymph were determined. Eight lungs were examined by light and electron microscopy. There was a direct relationship between right duct lymph flow (RDLF in milliters per hour per gram dry lung) and extravascular lung water (Qwl in milliliters per gram dry lung) which was best described by the equation RDLF=0.75-0.26 Qwl+0.03 (Qwl).2 Dogs with severe ANTU-induced edema had extensive lung capillary endothelial destruction but only mild interstitial swelling and no visible damage to type I alveolar epithelial cells. Cardiac output, pulmonary artery and wedge pressures, and protein and electrolyte concentrations did not correlate with either extravascular water or right duct flow. Thus, in ANTU-induced pulmonary edema right duct lymph flow was directly related to extravascular lung water with the highest flows occurring with severe edema. The absence of a rapid increase in lymph flow with small increases in extravascular water may be due to early sequestration of fluid in the alveolar space. Hemodynamic changes did not account for changes in lung water or lymph flow. The pulmonary interstitial factors relating increased extravascular water to lymph drainage remain to be determined.

Glucose penetration into liver.

To further define the action of insulin on liver metabolism, studies were undertaken to determine whether the cell wall could be the site of action as has been proposed for muscle. Control rats and those injected with varying amounts of glucose were found to have a higher glucose concentration in liver water compared to plasma water with low plasma glucose levels and vice-versa with high plasma glucose levels. Radioactive glucose was freely distributed into total liver water in dogs whether the liver was taking up or producing glucose. Other compounds which entered rat liver cells were fructose, mannose, galactose, sorbitol, mannitol, glycerol and α-methyl glucopyranoside. Maltose, sucrose and raffinose were restricted to extracellular fluid. Alloxan diabetic rats likewise showed free equilibration of radioactive glucose between plasma and liver water. The free permeability of liver to glucose and other small carbohydrates suggests that insulin in liver alters intracellular enzyme functions and not permeability of the cell wall as in muscle.

Distribution of Sulfanilamide and Acetylsulfanilamide Between Cells and Extracellular Fluid.

Since sulfanilamide when given to dogs has been recovered in all organs in concentrations proportional to the water contents thereof, it has been suggested that this drug might offer a convenient means of estimating total body water. A method which involves the same principles as those employed in the dye technic for estimation of plasma volume has been used to estimate the total body water in dogs. The results indicated that sulfanilamide was dissolved in approximately the same amount of water as urea, which was administered simultaneously; and, since urea is known to be distributed uniformly in body water, the sulfanilamide method seemed applicable for dogs. In expectation that this method might apply to man as well as dogs, the following experiments were carried out. These were done in the hope that the acetylation of sulfanilamide, a process which, although absent in dogs, is normally present in man,, might not interfere with the determination. Four subjects in basal conditions received an intravenous injection of 40 cc of a 700 mg % solution of sulfanilamide in 0.85% saline. Two additional subjects received intravenous injections of 100 cc of a 100 mg % solution of acetylsulfanilamide. Samples of blood for control determinations were taken before the injection, and subsequent samples were taken in bottles containing the appropriate amount of potassium oxalate (2 mg per cc of whole blood) at varying intervals following the injection. The whole blood was analyzed for both free and total sulfanilamide by the revised method of Marshall, and the final color reaction was read on an Evelyn Photoelectric colorimeter. The resulting figures showed that in 3 of the 4 subjects who received sulfanilamide there were gross irregularities in the disappearance curves due to a 10 to 30% rise in the concentration of the total sulfanilamide in the blood occurring from 1 1/2 to 6 hours after the injection.