Method and system for treating tissue swelling

Abstract

A system and related methods and components for treating a tissue site exhibiting interstitial hypertension, including tissue swelling, and particularly swelling associated with cerebral edema, compartment syndrome, and congestive heart failure, by the use of water removal therapy, in order to remove only water from biological fluids. Included also is a system for such use that incorporates one or more monitors, optionally in addition to the use of water removal therapy. By removing only water, all other biologic agents, including essentially all solutes and formed blood elements (such as cells) are increased in concentration in the remaining bodily fluid(s). WRT can be applied to several clinical conditions in which there is an excess of water, and is ideally used in an extracorporeal fashion, in combination with other functions and related components as well, including ultrafiltration.

Description

FIELD OF THE INVENTION [0001] The present invention relates to methods and apparatuses for addressing situations in which interstitial hypertension (elevated tissue pressure) occurs within the body, including in situations of tissue swelling and the hypertension associated with formation of solid and semisolid tumors. In another aspect, the invention relates to diagnostic and therapeutic methods and apparatuses that include the placement of semipermeable catheters and membranes within the body, for use in removing water and / or fluid components from the tissue site and / or for delivering agents such as bioactive agents to sites exhibiting interstitial hypertension. In yet another aspect, the invention relates to diagnostic and therapeutic methods and apparatuses adapted to monitor various physiologic parameters in the course of tissue swelling, as well as methods and apparatuses adapted to deliver media, including gases and liquids, to catheters positioned within a tissue, including t...

AI Technical Summary

Benefits of technology

[0061]FIG. 33 is a cut-away perspective view of a catheter assembly similar to the catheter assembly shown in FIG. 32.

Problems solved by technology

Acute compartment syndrome generally involves impaired circulation within an enclosed fascial space (e.g., the anterior compartment of the lower leg), leading to increased tissue pressure and necrosis of muscle and nerves.

There remain few conventional treatment options, and they tend to be of limited efficacy.

While the placement of an ICP monitor is invasive, the benefits of ICP monitoring are felt to offset this factor, carry a relatively small risk of complications (e.g., infection, hemorrhage, malfunction, obstruction or malposition), and rarely result in increased patient morbidity.

As fluid is removed, however, brain swelling often progresses to the point where the ventricular system is compressed and the ability to drain CSF can be compromised.

This may be exacerbated by overdrainage, leading to the ventricular walls or the choroid plexus actually collapsing in a manner that occludes the orifices of the catheter.

The therapeutic efficacy of convective CSF drainage by conventional ventriculostomy catheters, therefore, has been limited to date.

If CHF is severe, blood flow to the kidneys is restricted such that renal function is impaired without treatment.

This resistance leads to fluid overload and a diminished quality of life.

Severe fluid overload often leads to hospitalization and more intensive medical therapy.

In addition to the tissue swelling that occurs during CHF, the failing heart is not able to maintain perfusion to vital organs.

With increasing water and sodium retention, the venous system becomes overfilled, resulting in an increase in interstitial fluid, and the resulting clinical symptoms of CHF.

Excess interstitial fluid results in pulmonary edema, pitting edema of the lower limbs, sacral edema, and ascites.

Low sodium levels are a problem for several reasons, including: 1) Poor response to drug treatment.

Patients with low sodium become refractory to medical treatment and require hospitalization.

3) Increased risk of inpatient death.

4) Increased risk of mortality after discharge.

These therapies, including hemofiltration, have not only been shown to treat fluid overload, but have also demonstrated the potential reversibility of CHF.

None of the emerging therapies address the problem of hyponatremia (low sodium) however, and some can actually tend to aggravate the problem.

The ultrafiltrate is removed from the blood, which results in decreased blood volume and subsequent refilling of plasma fluid from the interstitial space.

Ultrafiltration does not, however, improve serum sodium levels.

Furthermore, ultrafiltration alone does not increase renal excretion of sodium, and studies have shown a reduction in urinary sodium levels after ultrafiltration.

Renin-angiotensin results in retention of sodium and water and is counterproductive to the intention of ultrafiltration.

Even with pharmacological treatment, however, it appears that hyponatremia persists.

While the CHF Solutions technology may provide desirable attributes, it appears to be neither intended nor designed to address corresponding hyponatremia.

The delivery of drugs to tumors, however, poses additional challenges beyond those associated with both systemic and site specific delivery techniques.

Reduced perfusion to tumors is known to limit the ability to effectively deliver chemotherapeutic agents to the tumor.

DiResta et al. also demonstrated that fluid removal will result in shrinkage of the tumor compared to controls when chemotherapeutic drug is given systemically.

Unfortunately, most drugs which showed promising effects in vitro have failed to be as effective in vivo, particularly in solid tumors.

Despite these promising findings, the above-cited DiResta et al. articles each describe various “limitations” to their use of ALS, including apparent limitations regarding the extent of vacuum that can be safely applied to the aspiration probe, and the concern that drugs may be removed along with the fluid itself.

In addition, the small holes in the ALS may tend to become blocked with time.

As a result, long term use of the ALS could potentially be problematic.

Long term use of the ALS may further be complicated by the lack of a mechanism to secure the drains of the ALS to the tissue so that the drains remain spatially fixed.

Finally, the ALS had no features that facilitate use with adjunct therapies that enhance drug delivery.

However, until now, no other adjunct therapy has been used in conjunction with the ALS.

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