Influence of hypertonic‐hyperoncotic solution and furosemide on canine hydrostatic pulmonary oedema resorption.

Abstract

SUMMARY1. This study aimed at enhancing the clearance of experimental hydrostatic pulmonary oedema in dogs using hypertonic-hyperoncotic solution (HHS) and furosemide.2. Anaesthetized dogs (n = 20) were mechanically ventilated with a positive endexpiratory pressure of 10 cmH20 (1-0 kPa).3. Hydrostatic pulmonary oedema was induced by inflating a balloon inserted into the left atrium and simultaneously infusing isotonic saline rapidly. Gedema formation was terminated by deflating the balloon and reducing the infusion rate.4. Four groups were studied: A, control; B, furosemide; C, HHS and D, HHS + furosemide. HHS, 6 ml kg-', was given as a bolus injection and furosemide, 1 mg kg-', intravenously as a bolus followed by an infusion of 0 5 mg kg-' h-1. All dogs were studied for 4 h.5. Serum osmolarity, plasma colloid oncotic pressure and diuresis in groups C and D (HHS groups) substantially increased; haemoglobin concentration decreased and pulmonary arterial wedge pressure remained constant.6. Despite the combination of these factors favouring fluid flux from the extravascular to the intravascular compartment, extravascular lung water measured with the double indicator dilution technique decreased no faster in the HHS groups than in the two other groups (from over 26 to approximately 19 ml kg-' in groups A, C and D and to 14-7 in group B (only furosemide)).7. This was confirmed by postmortem gravimetric measurements of extravascular lung water; A, 11-0+5-7; B, 9-7+3-3; C, 10-5+331 and D, 106±+1-8 g kg-'.

Accuracy of the double indicator method for measurement of extravascular lung water depends on the type of acute lung injury*

“…Our results are in agreement with previous studies that found an underestimation of EVLW by 30 -40% in similar OA models (23,24). Other studies in normal lungs or after indirect injury found either overestimation by the DI method or underestimation (6,11,(25)(26)(27)(28). This variability in correlation equations could depend on the type of animal model as well as on the type of methodology used.…”

Hypertonic‐hyperoncotic solution increases canine lymph flows

“…The circulatory response to HHS in this study is similar to those previously documented in hypovolaemic conditions (4,6,22) and during pulmonary oedema (10). We chose normovolaemic animals because in the hypovolaemic state basal lymph flows can be so small, making detection of decreased lymphatic flow impossible and subsequently, when oedema formation starts, the maximum lymph flow has already been attained.…”

“…This has led to the speculation that HHS might even be of therapeutic value in normo-and hypervolaemic conditions by mobilising extravascular fluid into the vascular compartment and increasing diuresis. In an earlier study, however, we found that rapid intravenous administration of HHS, in a canine hydrostatic pulmonary oedema model, did not influence the rate of reabsorption of oedema despite changes in parameters favouring oedema clearance (10). The aim of this study was to measure thoracic and abdominal lymph flows during the administration of HHS in an attempt to increase our understanding of HHS influence on pulmonary microcirculation and fluid balance in a lunghealthy nonhvpovolaemic condition.…”

Postanaesthetic pulmonary oedema in a dog following intravenous naloxone administration after upper airway surgery

“…Appropriate mechanical ventilation strategies and diuretics are considered the mainstay of treatment for acute pulmonary oedema (Wickerts and others 1992). Furosemide, a loop diuretic, has been shown to assist resolution of pulmonary oedema and is thought to cause an increase in colloid oncotic pressure that facilitates resorption of extravascular fluid in the lungs (Wickerts and others 1991).…”