Abstract:
An infusor system for administering medications to a venous blood vessel in the body of a patient. The infusor system includes a flexible, elongated delivery tube having opposite ends. One of the ends is couplable to a supply of liquid medication, which is remote from the venous blood vessel. The system further includes a delivery component coupled to the other end of the delivery tube. This delivery component is adaptable to be placed in confronting relationship with the venous blood vessel so that medication from said supply may be introduced directly into the venous blood vessel and distributed in the body of the patient. The infusor system further includes a pressure-altering device used for increasing intraabdominal pressure in the body of the patient. Sampling of venous blood from the meningorrhachidian vasculature is also possible.

Description:
FIELD OF THE INVENTION 
   The present invention relates generally to the administration of medications to patients, and specifically, to the administration of medications through the venous system of a patient, and more specifically, through the superficial to sacral venous system of a patient. 
   BACKGROUND OF THE INVENTION 
   The effective administration of medications for the treatment of disease symptoms and for the alleviation of pain, i.e., pain management, is an important aspect to the overall treatment of patients for both curable diseases and terminal illnesses. Particularly, the effective administration of medications in patients experiencing chronic pain associated with a terminal illness is particularly important, because such pain management requires constant administration of medication over prolonged periods of time. As a result, the management of pain for terminally ill patients, such as terminal cancer and those afflicted with HIV, has come to the forefront as the medical profession seeks to alleviate pain to allow the patient to comfortably pass away. 
   Oral administration has been widely utilized in the past for dispensing pain medications such as narcotic and non-narcotic analgesics. However, oral administration is oftentimes not possible due to an obstruction blocking the oral and gastrointestinal tract, or due to severe nausea/vomiting by the patient. Such gastrointestinal problems are often experienced by terminally ill patients whose bodies are slowly deteriorating. 
   Parenteral administration, or, administration outside of the intestine, such as through bolus injections or slow infusions are also widely utilized. Intravenous (IV) drips are particularly popular for long-term administration of a medication in controlled dosages. However, parenteral administration is invasive and usually painful to the patient. Undesirable local reactions can occur at the site of the injection or infusion, and wheal, or skin elevation, occurs due to the injections or infusions which involve a needle and are subcutaneous, or beneath the skin. Furthermore, parenteral administration of medications may not be possible if there is a lack of peripheral vasculature and blood flow cannot move to certain areas of the body. Also, some terminally ill patients may refuse parenteral administration of medications. 
   Parenteral administration of medications is also not practical for long-term patient care due to the requirement that proper sites must be utilized for effective administration. Terminally ill patients may not have the physical capability of performing an injection procedure, and if physically able, may not have the knowledge to properly choose an injection site and administer the medication. Thus, while parenteral administration may be effective, a properly trained healthcare provider is usually necessary for administration. When long-term patient care must be provided by an untrained person, injection techniques may become impossible to implement, requiring a patient to stay in a hospital or other medical facility indefinitely. 
   Rectal administration of medication is widely used for administering a number of different medications, including non-narcotic and narcotic analgesics for pain management, antinausea medications, and steroids. However, currently available rectal administration techniques involve the use of suppositories which contain a fixed dosing of medication. The suppositories are placed within the rectum for one-time, slow, and continuous absorption. Therefore, there is generally no control over the administration rate except that provided by the fixed breakdown of the suppository and the absorption rate of the rectal mucous membrane. As such, suppositories do not provide the needed flexibility in the management of pain which often requires quick bolus administrations to combat acute pain and acute worsening of pain. Furthermore, since suppositories are generally single dose elements, extended care may require the continual insertion of single dose suppositories for continuous pain management. Such continuous monitoring is expensive and often requires a skilled caregiver when the patient is either unable or unwilling to insert the suppository. 
   For pain management, the intraspinal administration of non-narcotic and narcotic analgesics is important in alleviating acute and chronic pain. Approaches have been developed for delivering high concentrations of medications into the spinal cord; however, all such techniques are invasive and have associated risks related to the use of a catheter or pump for the injection or infusion. Furthermore, most of these techniques are generally expensive, as they require administration and monitoring by skilled medical personnel. 
   Therefore, alterative methods of administration that are less complex, demanding, and expensive, are desirable. 
   Recently, the use of the reversal of blood flow in the vertebral venous system or Batson&#39;s Plexus for rectal or intravenous administration of medications into selected pelvic region veins has shown promise as a method of administering analgesics and anesthetics at high concentration directly into the intraspinal areas. Reversal of flow in the Batson&#39;s Plexus refers to the physical phenomenon of reversal of blood flow in the veins of the vertebral structures when intraabdominal pressure is applied. Normally, the vertebral venous plexus in the pelvis, sacrum and lumbar spine assist in carrying the venous blood from the meningorrhachidian veins of the vertebral structures, including the spinal cord, to the sacrum and sacral plexus, the iliac veins and ultimately to the inferior vena cava and to the heart. However, the vertebral venous plexus or Batson&#39;s plexus is valveless so blood is free to flow in any direction. The Batson effect occurs upon increased intraabdominal pressure which causes reversal of pelvic and lumbar venous flow such that venous flow occurs from the sacral venous plexus and inferior vena cava into the meningorrhachidian blood vessels. In short, normal blood flow occurs from the spinal column toward the heart, but under Batson&#39;s described effect, blood flow can occur in the opposite direction, providing blood flow back to the spinal area. Using Batson&#39;s plexus reverse flow by increased intraabdominal pressure, in conjunction with the administration of analgesics using venous needle or indwelling venous catheter delivery of opioids, anesthetics or other medications into pelvic region veins that drain into the sacral plexus and Batson&#39;s plexus, the analgesic or other medication might be more efficiently and effectively administered at high concentrations to the spinal cord to alleviate pain without peripheral intravenous infusions. 
   Therefore, it is an objective of the present invention to administer medications to patients without the various drawbacks associated with traditional oral, rectal, and parenteral methods of administration discussed hereinabove. Furthermore, it is an objective to administer medication intravenously (IV) with greater flexibility and with central nervous system specific delivery than provided with currently available techniques. 
   Particularly, it is an objective of the present invention to administer non-narcotic and narcotic analgesics to continuous care and terminal patients for the management of acute and chronic pain. 
   It is a further objective of the present invention to administer medications in a nonpainful, noninvasive and safe way without incurring the large expense associated with procedures involving administration and continual monitoring by large numbers of skilled caretakers, such as physicians and nurses. Safe, effective and inexpensive pain management in economically depressed, third world countries is particularly important, as these countries often have large numbers of terminally ill patients without the requisite medical staff available. 
   It is a further objective of the present invention to provide greater flexibility in the administration of medications, both continuously and in bolus dosages and to provide for easy initiation and termination of the dispensing process. 
   It is a further objective of the present invention to administer medications so that the medications are rapidly and efficiently absorbed into the necessary areas of the body to alleviate the medical condition or the pain associated therewith. 
   It is also an objective of the present invention to more efficiently and effectively administer medications into the intraspinal area and particularly to administer anesthetics and analgesics into that area for pain management purposes. 
   It is also an objective of the present invention to more efficiently and effectively administer medications into the intraspinal and systemic circulation of multiple different pharmacologic agents for many different medical reasons. Medication that can be delivered by pelvic region veins and directed into the intraspinal area include any therapeutic or diagnostic agent that can be delivered by IV in any other area of the body. These include steroids, nonsteroidal anti-inflammatory agents, anti-infectives, oncolytics, immune therapies, antibleeding agents, anti-epileptic agents, fluid replacement, radiopaque x-ray imaging agents and magnetic resonance imaging agents, such as gadolinium, and radioactive diagnostic and radioactive therapeutic agents and experimental drugs (such as ziconotide, large molecules, nonpolar molecules, hormones, and immune modulating agents and other compounds, that may not or only poorly cross the blood-brain barrier, or that are poorly or nonabsorbed through the oral or rectal route) that may be useful to treat pain conditions, or hypothermia or hyperthermia therapy of the pelvic venous blood flow for therapeutic purposes. 
   SUMMARY OF THE INVENTION 
   The above-discussed objectives are addressed in the present invention which comprises an infusor system for administering medications to a patient through a venous needle or indwelling venous catheter. In a preferred embodiment of the invention, the infusor system is designed for use within the superficial to sacral venous system of a patient for administering medications into the body of the patient. 
   In a preferred embodiment, the infusor system comprises a needle or indwelling catheter that is placed into a superficial vein or veins of the pelvis or inguinal region including but not limited to the femoral vein, deep epigastric veins, deep circumflex iliac vein, internal iliac vein, internal pudic vein, common iliac vein, spermatic vein, dorsal vein of the penis, inguinal vein, pudendal vein, pubic veins, or genitofemoral vein. The system further comprises a delivery tube coupled at one end to a supply of liquid medication and at an opposite end to the venous needle or indwelling catheter. 
   The supply of medication is delivered into the tube and to the IV needle or indwelling catheter either continuously through an IV drip bag or a pump apparatus, or in a bolus dosage. To that end, the infusor system includes apparatus for coupling the IV needle or indwelling catheter to an IV bag or to a pump and also includes a bolus injection site. The infusor system further comprises a one-way valve in the delivery tube for allowing medication flow in only one direction, from the supply to the IV needle or indwelling catheter. 
   The infusor system eliminates the large expenses associated with other procedures which involve administration and continual monitoring by professional medical personnel. The IV needle or indwelling catheter of the infusor system may be inserted into the superficial vein or veins of the pelvis or inguinal region including, but not limited to, the femoral vein, deep epigastric veins, deep circumflex iliac vein, internal iliac vein, internal pudic vein, common iliac vein, spermatic vein, dorsal vein of the penis, inguinal vein, pudendal vein, pubic veins, or genitofemoral vein and left therein while medication is supplied. Furthermore, medication administration can be easily initiated and terminated by simply starting or stopping the flow of medication to the delivery IV needle or indwelling catheter. The infusor system provides safe, effective and inexpensive pain management and is particularly useful in economically depressed third-world countries which have large numbers of terminally ill patients who do not have the monetary resources to afford continuous attention by medical professionals, even if such professionals are available. The medications dispensed through the infusor system are rapidly and efficiently absorbed into the necessary areas of the body for alleviation of the medical condition or the pain associated therewith. Furthermore, a large number of medications, such as chemotherapy medications and some anesthetics, may be introduced through the superficial vein or veins of the pelvis or inguinal region including but not limited to the femoral vein, deep epigastric veins, deep circumflex iliac vein, internal iliac vein, internal pudic vein, common iliac vein, spermatic vein, dorsal vein of the penis, inguinal vein, pudendal vein, pubic veins, or genitofemoral vein. An IV method of use of the infusor system is particularly effective for the efficient administration of medications directly into the intraspinal area for pain management. 
   In an embodiment of the method of the present invention, the IV or indwelling catheter is placed within the superficial vein or veins of the pelvis or inguinal region including but not limited to the femoral vein, deep epigastric veins, deep circumflex iliac vein, internal iliac vein, internal pudic vein, common iliac vein, spermatic vein, dorsal vein of the penis, inguinal vein, pudendal vein, pubic veins, or genitofemoral vein, and medication is dispensed. Intraabdominal pressure is then increased by any number of different available methods, such as by utilizing an abdominal restraint or binder. The blood flow in the vertebral venous plexus is reversed and the dispensed medication is delivered from the rectal and sacral veins directly into the vertebral bones, the epidural and intrathecal space, and the spinal cord. By maintaining the increase in the intraabdominal pressure long enough, cranial structures will also receive the vertebral venous flow of medication. 
   Therefore, the infusor system of the present invention provides a more direct infusion of medication, either continuously or in bolus dosages, into the spinal cord and other vertebral structures, as compared to oral or parenteral administration, for more effective pain management. As such, analgesic medication, such as morphine, can be delivered in relatively higher concentrations to the spinal cord before circulating throughout the body and before significant dilution. Furthermore, the bypassing of liver metabolism provides a greater concentration of available medication to the necessary targeted areas. Since there are lower concentrations of the analgesics dispensed systemically within the body, side effects such as sedation, respiratory depression, nausea, and vomiting are reduced. Still further, utilizing the inventive method of the present invention, more costly injection procedures requiring skilled professionals are avoided when introducing medications within the epidural and intrathecal spaces of the spinal column. 
   These advantages and other advantages of the present invention will become more readily apparent below from the Brief Description of the Drawings and the Detailed Description of the Invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with a general description of the invention given above, and the detailed description of the embodiments given below, serve to explain the principles of the invention. 
       FIG. 1  is a schematic view of an embodiment of the infusor system of the present invention; 
       FIG. 1A  is an enlarged view, in partial cross-section, of a venous needle as used in accordance with the principles of the present invention; 
       FIG. 1B  is an enlarged view, in partial cross-section, of an indwelling venous catheter used in accordance with the principles of the present invention; 
       FIG. 1C  is an enlarged view, partly in cross-section, of an indwelling venous catheter inserted in a vein in accordance with the principles of the present invention; 
       FIG. 2  is an enlarged view, partly in cross-section, showing a venipuncture needle in position in a vein and the catheter used in accordance with the principles of the present invention about to be inserted through the needle into the vein; 
       FIG. 3  is a side view, in partial cross-section, of a patient body illustrating the infusor system used within the superficial to sacral venous system of the patient; 
       FIG. 4A  is a front view of a pressure-altering device, such as an abdominal binder, of the infusor system to be utilized with the tube and catheter of the present invention; and 
       FIG. 4B  is a side view of a patient&#39;s body, in partial cross-section, of a patient body, showing the pressure-altering device of the infusor system of the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  is a schematic view of one embodiment of the infusor system  10  of the present invention. The infusor system  10  includes a medication delivery tube  12  which is coupled to a supply of medication  14  to be dispensed therethrough. The tube  12  may be made of PVC material or of a biodegradable material for more environmentally safe disposal. The delivery tube  12  is coupled to a delivery component  18  for dispensing medication  16  delivered thereto by the tube  12 . Such a delivery component  18  may include, but is not limited to, a venous needle  20  or an indwelling venous catheter  22 . As discussed further hereinbelow, the delivery component  18 , such as the venous needle  20  or indwelling venous catheter  22 , is operable to direct medication  16  from the tube  12  to a venous system  24  of the patient. In one embodiment, the venous system  24  may be the superficial to sacral venous system of a patient, and in particular, the medication  16  may be directed into the superficial vein or veins  26  of the pelvis  28  or inguinal region  30  of a patient. 
     FIGS. 1A through 1C  show a venous needle  20  ( FIG. 1A ) and an indwelling venous catheter  22  ( FIGS. 1B and 1C ) that may be used in the infusor system  10  of the present invention. Referring to  FIG. 1A , a venous needle  20  is typically inserted into a patient with the needle  20  puncturing and protruding through the skin  32  and into the vein  26  of the patient following preparation and sterilization of the insertion site  34 . Thereafter, the venous needle  20  may be held in place by a plurality of tapes  36  which hold the venous needle  20  to the insertion site  34 . Referring to  FIGS. 1B and 1C , an indwelling venous catheter  22  may be inserted into a vein  26  beneath the skin  32  of a patient. In particular, a venipuncture needle  38  is inserted through the skin  32  and into a vein  26 , and the catheter  22  is inserted into the vein  26  through the venipuncture needle  38 . Once the catheter  22  has been inserted into the vein  26 , the venipuncture needle  38  used for the catheter insertion is removed, leaving the catheter  22  in the patient&#39;s vein  26 . 
   Referring now to  FIGS. 2 and 3 , then delivery component  18 , being an indwelling venous catheter  22  in the illustrated embodiment, is shown inserted into a portion of the superficial to sacral venous system  24  of a patient body  39 . Within this venous system  24 , the indwelling venous catheter  22  is able to deliver medication  16  through the tube  12  to a contact point  40 . This contact point  40  may be a superficial vein or veins  26  of the pelvis  28  or inguinal region  30 , including, but not limited to, the femoral vein, deep epigastric veins, deep circumflex iliac vein, internal iliac vein, pudic vein, internal pudic vein, external pudic vein, common iliac vein, spermatic vein, dorsal vein of the penis, inguinal vein, pudendal vein, pubic veins, or genitofemoral vein. It will be recognized by those of skill in the art that the contact point  40  may be in other veins  26  of the patient body  39 . 
   As illustrated in  FIG. 1 , the delivery tube  12  is coupled to a medication supply  14  and delivers medication  16  to the venous needle  20  or indwelling venous catheter  22  from the supply  14 . For example, a first end  42  of the delivery tube  12 , being the end opposite the venous needle  20  or indwelling venous catheter  22 , may be coupled to an IV drip bag  44  for continuously dispensing medications  16  at a controlled drip rate into the tube  12 . Alternatively, the first end  42  of the tube  12  may be connected to a pump device  46 , such as a Patient Controlled Analgesia, or PCA, pump for injecting medication  16  into the tube  12  at a predetermined pumping rate. Infusion rates and doses may be determined by a physician. 
   The tube  12  of the infusor system  10  of the present invention may also include a bolus injection dock  48  for receiving a syringe  50  to rapidly inject bolus dosages of medication  16  to be dispensed through the delivery component  18 , such as a venous needle  20  or indwelling venous catheter  22 . This may be used to alleviate acute pain or acute worsening of pain experienced by a patient utilizing the infusor system  10 . If a patient is using a home infusion pump, a preset “rescue” or bolus dose is set for every time the patient or caregiver presses an extra dose/rescue button, as with other infusion pumps, as is known to those skilled in the art. A one-way valve  52  ensures that medication  16  flows in the proper direction to the venous needle  20  or indwelling venous catheter  22 . 
   The embodiments of the infusor system  10  illustrated herein utilize venous needles  20  or indwelling venous catheters  22  which are designed and configured to be positioned within the veins  26  of the pelvis  28  or inguinal region  30 . However, the infusor system  10  might also be utilized with other venous systems  24  of the body  39  which are proximal to areas requiring medication  16 . For example, Batson&#39;s plexus extends up to the cervical (neck) region. Thus, a very long catheter, such as a cardiac catheter, could be extended up through the superficial pelvic veins, femoral veins, and several others, and into the vertebrovenous and meningorrhachidian vasculature (i.e. around the spinal canal and spinal cord and structures) and/or up to the base of the skull. This would allow for focal delivery and site directed delivery of medications into the higher central nervous system (CNS). 
   Although including an orifice  54  to direct liquid medicine from the tube  12  to the contact point  40 , namely, the superficial or sacral venous system  24  of a patient, the material utilized to form the venous needle  20  or indwelling venous catheter  22  should not absorb and hold the medication  16  away from the venous system  24 . Furthermore, the material should preferably not foster the growth of microfluora. While the infusor system  10  of the present invention utilizes a venous needle  20  or indwelling venous catheter  22  which is configured for remaining within a venous blood vessel  26 , it may be useful to precede the insertion of the venous needle  20  or indwelling venous catheter  22  with an anesthetic to prevent reaction to the venous needle  20  or indwelling venous catheter  22  as a foreign body. 
   Vein catheterization, in the method of the present invention, is performed by medical professionals. Likewise, a pressure-altering device  56 , such as an abdominal binder  58  ( FIGS. 4A and 4B ), may be applied to a patient and removed from a patient by medical personnel. In some situations, the patient may be able to remove and apply the binder  58  by himself after receiving training. Additionally, in the embodiment of the present invention wherein an IV may be attached to a home infusion pump  46 , such a pump  46  may also be turned on and off and bolus injections may be given by the patient, as with home infusion pumps  46  and diabetic pumps. Such pumps are commercially available from Deltec, Inc. of St. Paul, Minn. and Pharmacia of Kalamazoo, Mich. When using an abdominal binder  58  to affect reversal of flow through Batson&#39;s Plexus, the pressure applied to the binder  58  is controlled with a sphygmomanometer device or other devices, as is understood by those having skill in the relevant art. Continuous abdominal pressures to induce reversal of flow through Batson&#39;s plexus may range from about 15 mm Hg to about 150 mm Hg. Generally, obese individuals will use higher pressures, while thinner individuals will use lower pressures to induce reversal of flow through Batson&#39;s plexus. 
   As described previously, the delivery component  18  of the infusor system  10  may include a venous needle  20  or indwelling venous catheter  22 . The venous needle  20  or indwelling venous catheter  22  preferably ranges from very small needles measuring about 25 gauge to very large needles and catheters measuring 18 gauge or larger. The delivery component  18  should sustain a flow rate of medication suitable for the application being utilized. In general, infusion rates may be as slow as “TKO”, or “to keep open” rate such as 10 cc/hour (kept open by using an infusion pump), or may be relatively rapid rates of 100 cc/hr. Rapid rates may often be used in applications involving delivery of medication  16  to the central nervous system. Faster rates could be instilled depending on the medication  16  used and the need. As other examples, for morphine usage, a sustained flow rate of about 15-20 cc/hr at a morphine concentration of 5 mg/cc may be desired. Furthermore, the venous needle  20  or indwelling venous catheter  22  may have the capability of providing bolus dosage delivery of 10-20 cc/hr, either as a single dose or in multiple fractions of 20 cc/hour. 
   A standard intravenous catheter, such as an Angiocath®, may be used as a delivery component  18  in one particular embodiment of the present invention. This type of catheter is flexible and has a more rigid guide wire for insertion that is removed after insertion. Angiocath® catheters are commercially available from Becton, Dickinson and Company. In use, an angiocatheter, such as an Angiocath®, would be placed subcutaneously into a pelvic vein, such as a vein selected from the group described previously. Following placement of the angiocatheter, the sheath or guide wire is removed. Alternatively, a simple straight infusion needle could also be inserted into the most superficial of pelvic veins. These needles or catheters are then taped down or stitched down in the case of deep angiocatheters. 
   The elements of the infusor system  10  should preferably be able to withstand gamma radiation for the purpose of pre-use sterilization. Furthermore, the materials are preferably safe to use in the presence of medical diagnostic systems such as magnetic resonance imaging (MRI), x-ray, or computerized tomography (CT) scan. 
   Medication  16  dispensed through the venous needle  20  or indwelling venous catheter  22  is directed into the venous system  24  and distributed throughout the body  39  to address a targeted symptom or to alleviate pain experienced by the patient. Since the infusor system  10  of the invention is utilized within a venous system  24 , it is noninvasive and generally nonpainful. Since no injection is involved, use of the infusor system  10  of the invention is not accompanied by the various drawbacks and side effects experienced with parenteral administration. Furthermore, the infusor system  10  may be utilized with patients who cannot tolerate orally administered medications. The infusor system  10  provides great flexibility in the dispensing of medication  16  through IV bags  44  and pumps  46 . A bolus dosage of medication  16 , such as a dosage of morphine for a patient suffering acute pain, can be administered through the bolus dock and received directly into blood vessels. 
   The infusor system  10  is safe and inexpensive. Not only will the infusor system  10  be generally inexpensive to manufacture, but it is also generally inexpensive to utilize. Once the venous needle  20  or indwelling venous catheter  22  has been properly placed, it can be left therein to provide continuous medication  16  without the need for constant medical attention, which is often associated with parenteral administered medication. Furthermore, the infusor system  10  provides continuous dispensing, unlike individual pills or suppositories that the patient or medical professional must remember to administer at predetermined intervals. 
   A large number of medications, such as chemotherapy, steroids, anesthetics, opioids, and other narcotic and non-narcotic analgesics may be administered using the infusor system  10  of the present invention. During operation of the infusor system  10 , it is easy to initiate the administration of medication  16  simply by providing medication flow through the tube  12  and into the venous needle  20  or indwelling venous catheter  22 . Similarly, stopping the medication flow will terminate the administration, whereupon it can simply be reinitiated by again beginning flow through the delivery tube  12 . 
   In accordance with one inventive method for utilizing the infusor system  10 , use of the infusor system  10  is combined with intraabdominal pressure to infuse medication  16  directly into the spinal structure  60  and the cavities surrounding the spinal structure  60 . The administration of medication  16  directly into the intraspinal area, and particularly, the administration of opioids and other analgesics, is very useful for pain management. For effective intraspinal administration in accordance with the principles of the present invention, the venous needle  20  or indwelling venous catheter  22  is positioned within the superficial vein or veins  26  of the pelvis  28  or inguinal region  30  to deliver medication  16  into the superficial or sacral venous system  24 . Intraabdominal pressure is then increased to create a reversal of blood flow within the vertebral venous plexus, or Batson&#39;s plexus. The intraabdominal pressure may be applied by using an abdominal restraint or abdominal binder  58  or any other medically suitable method for creating intraabdominal pressure. The intraabdominal pressure may be set for each patient and is generally not altered after the optimal pressure for full reversal of Batson&#39;s plexus flow is determined. The optimal pressure may generally be a relatively low pressure of around 60 mm Hg to 90 mm Hg, but, as will be understood by those of skill in the relevant art, with obese persons, the pressure may be higher, and in very thin persons, the pressure may be lower. The Batson&#39;s plexus is valveless, and blood is free to flow in the reverse direction when intraabdominal pressure is applied. Normally, the vertebral venous plexus in the pelvis, sacrum, and lumbar spine assist in carrying the venous blood from the meningorrhachidian veins of vertebral structures, including the spinal cord, to the sacrum and sacral plexus, the iliac veins, and ultimately, to the inferior vena cava and to the heart. However, upon reversal of pelvic, sacral, and lumbar venous flow, the venous flow occurs from the sacral venous plexus and into the meningorrhachidian blood vessels. That is, the normal blood flow that occurs from the spinal column through the sacral plexus toward the heart reverses. This reversal of flow in the Batson&#39;s plexus occurs such that blood in the sacral plexus flows back into the spinal area. Therefore, using Batson&#39;s plexus reverse flow with the infusor system  10  in accordance with the principles of the present invention, medications  16  are delivered directly into venous blood vessels  26  and more effectively and efficiently administered to the spinal cord, such as to alleviate pain. For example, morphine administered utilizing the infusor system  10  with increased intraabdominal pressure, is delivered in high concentrations to the spinal cord and other vertebral structures. 
   Minimal systemic dosing of morphine or other medication  16  occurs utilizing the inventive method, and thus, provides a number of distinct advantages. Concentrated medications  16 , such as analgesics, are delivered into the spinal cord and other vertebral structures before circulating throughout the body  39  and before significant dilution occurs. Furthermore, the medications  16  are directly delivered into the vertebral structures  60  before liver metabolism of the medication  16  occurs. With a greater concentration of the medication  16  directed to the vertebral structures  60  instead of systemically throughout the body  39 , side effects such as sedation, respiratory depression, nausea, and vomiting are reduced because there are lower concentrations of the medication  16  to the brain and brainstem. Furthermore, utilizing the inventive method, the delivery of medications  16  can be given intermittently, if desired, into the vertebral venous plexus using intermittent intraabdominal pressure, and then a systemic delivery may be initiated simply by removing the intraabdominal pressure. Therefore, high concentrations of an analgesic might be infused intraspinally to manage acute pain, and then systemically for continuous management of less acute, chronic pain. A further advantage of the inventive method is that medication  16  may be administered epidurally, that is, outside of the covering of the spinal cord, and intrathecally, that is, within the spinal fluid surrounding the spinal cord without the use of injections, which are generally costly and usually require administration by a trained anesthesiologist due to potential risks, and also require continuous monitoring by trained personnel. Therefore, the cost and the risks of effective pain management are reduced. 
   Drugs that are delivered intrathecally or epidurally or both, and that may now be delivered more safely, inexpensively and efficiently by reversal Batson&#39;s plexus include: chemotherapy drugs (thiotepa, methotrexate, ARA-C, steroids); antifungals (amphotericin and others); pain medications (morphine sulfate, hydromorphone, methadone, fentanyl); adjuvant analgesics (clonidine), alpha adrenergic agents; anti-spasticity drugs (baclofen); and anesthetics (bupivacaine, lidocaine, etc.). 
   In yet another embodiment of the present invention, the delivery tube  12  may be inserted through the pelvic veins and sacral veins and up into the vertebrovenous plexus region for aspiration or sampling of venous blood from the vertebrovenous plexus and meningorrhachidian vasculature. The purpose of the sampling of blood is to determine pathology or lack of pathology from this area of the body, such as meningitis; cell metabolism products such as lactic acid, pyruvic acid, cytokines; and biological markers such as beta-microglobulin, carcinoembryonic antigen (CEA), and other indicators of malignancies. 
   While the present invention has been disclosed by reference to the details of preferred embodiments of the invention, it is to be understood that the disclosure is intended in an illustrative rather than in a limiting sense, as it is contemplated that modifications will readily occur to those skilled in the art, within the spirit of the invention and the scope of the appended claims.