AbstractEdema represents the accumulation of excess liquid in theinterstitial (extracellular) spaces of a tissue or in pre-existing cavities. Itmay affect any organ, but most often it appears in : subcutaneous tissues, lungand brain.
There are two main types of pulmonary edema, hydrostatic andnoncardiogenic pulmonary edema. Each occur in different clinical conditionsrequire seperate therapy and have a different prognosis. There are many keysymptoms that can lead to the diagnosis of pulmonary edema and reasons why thecondition would arise. Following diagnosis comes the treatment and prognosiswill be discussed. Pulmonary EdemaMany come to believe that the lungs are a dryorgan and the only time where fluid is involved is when the lungs develop acondition called pulmonary edema. When in fact the lungs have a fluid that iscalled filtrate that is in the interstitial spaces of the lungs.
There are twomain types of pulmonary edema. The first is cardiogenic from left sided heartfailure. The second is is from injury. Both require different treatments andthe outcomes are also different.Hydrostatic and osmotic pressureHydrostatic pressure is the pressureexperienced by a point inside the fluid. This is the pressure of nonflowingwater.
Osmotic pressure is the pressure that stops the fluid transfer of thesemi permeable membrane in the lungs. The concentrated solute tends to move tothe less concentrated side. Often this means moving either in or out of a semipermeable membrane when it comes to the lungs. Fluid in the lungs move throughthe pulmonary capillary membrane. Raising the hydrostatic pressure could havean effect on the body and the lungs. Common actions such as exercise do notnormally effect the permeability of the membrane by making it more permeable.When the hydrostatic pressure does increase the membrane becomes more porous.
Cardiogenic Edema is a buildup of fluid in the lungs thatcan come from either an increase in pressure from fluid or from a weakening ofthe membrane that normally regulates the amount of fluid that moves back andforth through the pulmonary capillary membrane. When the left ventricle failsthe left side of the heart cannot adequately eject blood and it thus builds upin the lungs. An elevation in pulmonary capillary wedge pressure results fromthe hearts inability to pump the blood out of the pulmonary circulation. Whenthe fluid entered the lungs, this makes fine crackles when being auscultated. Anincrease of fluid in the lungs makes diffusion impaired as it is difficult todiffuse oxygen into the blood stream through all the fluid. Noncardiogenic.
Pulmonary edema can also be caused byneurogenic causes such as head trauma or seizures. Injury to the lungs director indirect can also cause pulmonary edema. There is a decently large list ofthings such as aspiration, severe infection, inhalation of hot or toxic gases.
The hanta virus and having a blood transfusion all can cause pulmonary edema. Obesityand an infection such as a pneumonia can also be causes. Often noncardiogenicedema can lead to ARDS. ARDS is acute respiratory distress syndrome. Flash pulmonary edema. Flashpulmonary edema is a rapid onset of pulmonary edema.
Often caused by an acutemyocardial infraction or mitral regurgitation. Mitral valve regurgitation iswhen the valve is letting blood leak backwards into the heart. Typically,valves work as one way gates the mitral specifically allowing the blood flowfrom the left upper part of the heart, the atrium, to the lower, the ventricle.Signs and symptoms. Symptoms may start suddenly and gradually getworse.
With cardiogenic pulmonary edema symptoms tend to have a slower onsetthan with noncardiogenic pulmonary edema. Cardiogenic pulmonary edema can beassociated with the signs of peripheral edema which can often be “pittingedema”. You often also see JVD jugular vein distention with cardiogenicpulmonary edema. Many patients with pulmonary edema tend to have tightening ofthe chest with difficulty breathing and extreme shortness of breath. Patientstend to have cyanosis which is characterized as a bluish tinting of thenailbeds and the lips. Paleness and sweating is also a sign of pulmonary edema.Signs that signify pulmonary edema can be fine crackles upon auscultation ofthe chest.
To verify such findings a physician may order a chest x-ray amongother test such s an electrocardiogram. Echocardiogram and on some occasions aCT scan may be ordered to confirm pulmonary edema.Treatmentand prevention.In efforts to raise the patients’ oxygenlevels oxygen is typically one of the first treatments ordered by thephysician. If simple oxygen is not enough to bring up the patients hypoxia anoninvasive positive pressure ventilation also known as BIPAP can be used tooffer extra pressure to help push oxygen into the blood into the blood stream.This extra pressure is needed due to the fluid in the lungs making it difficultfor oxygen to diffuse into the blood. In severe cases intubation is the chosenmethod of oxygenation. Often diuretics are given in efforts to reduce theamount of fluids the patient is retaining.
Usually this means an increase ofurine output once the medication is given. Often cardiogenic pulmonary edemapatients also receive inotropic drugs which help the contractibility of theheart to help sustain blood pressure. This can be given as a temporarytreatment while the underlying cause is addressed. Prevention can be for thosewith underlying heart disease, control of those symptoms can help to preventpulmonary edema for heart patients.