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Dynamic Infusion Cavernosometry And Cavernosography.

With erectile dysfunction's impact on society, the need for developing a comprehensive plan for accurate diagnosis is indicated. Dynamic infusion cavernosometry and cavernosography (DICC) offers an effective tool for evaluating the hemodynamic status of erectile dysfunction.

Objectives

This educational activity is designed for nurses and other health care professionals who care for and educate patients regarding dynamic infusion cavernosometry and cavernosography. The multiple choice examination that follows is designed to test your achievement of the following educational objectives. After studying this offering, you will be able to:

1. Anticipate the needs of the patient undergoing the DICC.

2. Assist with the procedure of DICC.

Dynamic infusion cavernosometry and cavernosography (DICC) is not a widely performed procedure for evaluating erectile dysfunction (ED). Although less-invasive methods of evaluation, such as nocturnal penile tumescence monitoring and penile duplex Doppler ultrasonography are often chosen, they may not correlate with the occurrence of corporal leakage (Sattar et al., 1996). As a result, DICC may offer new insights and treatment options for ED. DICC is also known as direct infusion cavernosometry and cavernosography as well as dynamic pharmacoinfusion cavernosometry and cavernosography (DPCC). Another alternative to DICC or DPCC is gravity cavernosometry. In this article, the procedure for DICC will be discussed.

Review of Erectile Dysfunction

Erectile dysfunction (ED) affects approximately 10 to 20 million men in the United States (NIH Consensus Development Panel on Impotence, 1993). It is defined "as the inability to achieve or maintain an erection sufficient for satisfactory sexual performance" (NIH, 1993). ED often is a symptom of other medical conditions such as heart disease, diabetes, vascular disease, hypertension, hypercholesteremia, pelvic trauma and surgery, medications, and tobacco. The U.S. Agency for Health Care Policy and Research (1996) guidelines for smoking cessation cite impotence as one of the preventable side effects of smoking.

Psychological problems are also important contributing factors that impair sexual performance. Even when due to a physical condition, impotence often has psychological implications for men and their partners.

An erection is a balance between inflow and outflow of blood within the corpora of the penis. The corpora cavernosa are the erectile tissues of the penis. The erection is induced by smooth muscle relaxation of the arterial vessels that deliver blood to the corpora. Adequate relaxation of the cavernosal muscle produces an increase in the intracavernosal pressure, which occludes the veins that leave the cavernosum. The occlusion of the veins is key for retaining blood within the corpora. This occlusion can only happen if corporal smooth muscle relaxation occurs. Any variation in inflow or outflow of blood supply can cause ED (Colpo, 1998). Arterial inflow and venous outflow resistance are the two hemodynamic factors that determine erections and they are associated with complete relaxation of smooth muscle of the corpora cavernosa (Goldstein, Hatzichristou, & Pescatori, 1994).

Goldstein, Krane, Greenfield, and Padma-Nathan (1990) have described the following pathophysiology of erectile dysfunction:

* Failure to initiate -- the inability to initiate change neurologically in smooth muscle tone to allow hemo-dynamic changes to occur. The arterial and veno-occlusive response to pharmacologic injections is normal. Spinal cord injury, multiple sclerosis, and radical pelvic surgery can cause this.

* Failure to fill -- deficit in cavernosal arterial system causing a reduction in occlusion pressure. This can be caused by atherosclerotic vascular disease, tobacco, hypertension, diabetes, high cholesterol, radiation and stress, or traumatic arterial occlusion (pelvic fracture or blunt perineal trauma).

* Fallure to store -- functional and anatomical impairment in corporal veno-occlusive function. This may be caused by:

1. Fibrosis secondary to atherosclerosis, Peyronie's disease or trauma.

2. Vascular dysfunction secondary to hypertension, hypercholesterolemia, diabetes, and tobacco which may hinder the local relaxation response.

3. Myopathy from diabetes or ischemia which impairs smooth muscle relaxation.

4. Anatomic communication after priapism repair (Goldstein et al., 1990).

Dynamic Infusion Cavernosometry and Cavernosography

Definition. According to the AUA Clinical Practice Guidelines, the measurement of corporovenous occlusive status is generally done by performing DICC after vasoactive drug injection. Complete smooth muscle (cavernosal) relaxation must be obtained by vasoactive drug injection. Patient anxiety may inhibit complete relaxation. If relaxation does not occur, a false diagnosis of corporovenous occlusive dysfunction may be made. DICC creates passive venoocclusion of the corpora by dilating cavernosal sinus spaces with normal saline. The maintenance flow rate is the speed of pressure decline when infusion is stopped (Chang & Lue, 1997). Penile arterial flow occlusion pressure is used to evaluate cavernosal artery function (redundant with ultrasound) (Chang & Lue, 1997). Venous occlusion defects require increased initial and maintenance flow rates (Chang & Lue, 1997). DICC is also useful in evaluating Peyronie's disease, penile trauma, and priapism (King, Lewis, & McKusick, 1994).

Trying to measure penile venous function by saline-induced erections does not activate the physiologic veno-occlusion mechanism and large fluid volumes may be harmful to patients with vascular compromise (Lue & Donatucci, 1994). King et al. (1994) suggest the use of a vasodilator injection to activate the veno-occlusive mechanism. After injection of pharmacologic agents more physiologic smooth muscles of sinus spaces are relaxed. But results can be affected by psychologic inhibition (Lue & Donatucci, 1994).

Procedure. DICC procedure consists of four phases. At Hackensack University Medical Center, the procedure is performed in the urology center. The physician, nurse, and urology assistant are involved in the procedure.

Equilibrium pressure. The equilibrium pressure reflects cavernosal arterial systolic occlusion pressure (CASOP) minus the loss of pressure from corporal venoocclusive function (CVOF) (Goldstein et al., 1990) (see Figure 1). The effectiveness of corporal veno-occlusive function and the degree of cavernosal arterial inflow obstruction will affect the amount of time needed to reach equilibrium state (Goldstein et al., 1990). Normally, baseline venous pressure 6 to 8 mm Hg and 90 to 100 mm Hg equals equilibrium (Goldstein et al., 1990).

After obtaining informed consent, the patient is asked to change into a hospital gown and is placed supine on a radiographic table. The penis is prepped with povidone antiseptic and a sterile field is created. The penis is then anesthetized by injection of 1% Xylocaine[R]. While the penis is becoming anesthetized the sterile tubing is attached to the pressure transducer dome which is connected to the infusion pump. A backwash of sterile heparinized saline is placed in a basin for priming the transducer tubing. Butterfly needles are then inserted intracavernosally and flushed with the sterile heparinized saline solution. If a bleb is formed or saline is noted in the urethral meatus the needle is removed and the area compressed for 5 minutes before a second attempt is made. Failure to do so may result in formation of hematoma or unnecessary bleeding of the penile shaft. The pharmacologic agent to be used, such as papaverine or prostaglandin [E.sub.1] (20-40 mcg), is given via this butterily. The drug used in o ur center is papaverine at a dose of 30 mg. This has been found in previous studies to cause the smooth muscle relaxation necessary for DICC. After administering the papaverine, intracavernosal pressure is monitored to determine when the readings stabilize. This stabilization of readings is considered the equilibrium state. The pressure reading and the time are documented.

Rate of fall. The rate of fall examines the rate of corporal body pressure fall from a controlled situation over a specific period of time (Goldstein et at, 1990). A second butterfly is placed in the opposite corporal body and flushed with sterile heparinized saline solution to monitor pressure loss. Again, if a bleb is formed or saline is noted in the urethral meatus the needle is removed and the area compressed for 5 minutes before a second attempt is made. The patient should be aware that he may feel pressure as the infusion is started and maintained. The physician is able to control the infusion pump via a foot pedal. The infusion is delivered at a rate that will maximize corporal body pressure, usually no greater than 120 ml/min or at a suprasystolic pressure of 150 mmHg. When the pressure is obtained and maintained the infusion is stopped and the rate of fall is noted at 30 seconds. This portion of the test is repeated two or three times for accuracy and reproducibility (150 mm Hg - 30 second drop = -- ---).

Cavernosal artery systolic occlusion pressure. To determine GASOP, a Doppler ultrasound probe is placed over the left and right corporal body and the cavernosal arterial flow is recorded. The pressure within the corporal body is then elevated above the cavernosal arterial systolic occlusion pressure by an infusion of heparinized saline. When the Doppler signal disappears the infusion is stopped. Without the continuous infusion the cavernosal pressure decreases and the signal reappears, this value is noted and recorded (Goldstein et al., 1990). The reappearance of the signal is the cavernosal pressure and this number is compared to the mean arterial blood pressure (MAP) and a left and right gradient is determined (cayernosal pressure - MAP = gradient).

Cavernosography. Cavernosography is performed only when a veno-occlusive problem has been demonstrated or is suspected. During this procedure, a contrast material is infused at a rate to obtain a pressure in the penis of 90 mmHg, which is physiologic pressure. The patient must be aware that the penis is going to be maintained erect while the x-rays are done. Fluoroscopy views include anteroposterior and right and left oblique. The x-ray unit must be positioned to include the perineum along with the penis. Fluoroscopy is done to localize the areas and degree of venous leakage (Goldstein et al., 1990). If a leak is visualized, the results are documented as minimal, moderate, or diffuse. Any penile curvature is also documented as dorsal or ventral, right or left, and the degree of curve. The penis is observed for resolution of the erection. In the event of priapism, the erection is pharmacologically reduced by infusing incremental doses of an adrenergic agonist, such as ephedrine, to the onset of detumescence.

Post-Procedure Care

Once the test is complete the butterfly needles are removed and pressure held on the penis for 5 minutes followed by the application of elastic wrap (Coflex[R]) for continued compression. The patient is instructed to remove the elastic wrap when he arrives home. The patient is assisted to a sitting position and allowed to dangle. Some patients may complain of lightheadedness after lying flat for the procedure. As long as the patient's blood pressure is within normal range for the patient, he can be assisted to the bathroom to clean up and dress.

Patients schedule a followup appointment at the doctor's office to discuss the results of the procedure and the possible treatment options available. Some patients require more diagnostic testing including an arteriogram for evaluation if arterial revascularization surgery is being considered. Other patients discover that once surgery is performed to correct their Peyronie's disease that the likelihood for adequate erections is good. Patients may also find out that the corrective surgery will repair the bend in the penis but they will continue to suffer from erectile dysfunction secondary to a venous leak and that implant surgery should be considered. Patients usually tolerate the procedure well and are pleased to get answers to the questions that they have been asking.

Peggy L. Ford, RNC, CETN, is a Nurse Clinician, Urology Service, Hackensack University Medical Center, Hackensack, NJ, and is in the Master's Degree in Nursing Education Program, William Paterson University, Wayne, NJ.

References

Chang, J.J., & Lue, T.F. (1997). Venous impotence. In J. J. Mulcahy (Ed.), Diognosis and management of male sexual dysfunction (pp.148-164). New York: Igaku-Shoin.

Colpo, L.M. (1998). Evaluation, treatment, and management of erectile dysfunction: An overview. Urologic Nursing, 18(2). 100-106.

Goldstein, I., Hatzichristou, D.G., & Pescatori, E.S. (1994). Pelvic, perineal, and penile trauma-associated arteriogenic impotence: Pathophysiologic mechanisms and the role of microvascular arterial bypass surgery. In A.H. Bennett (Ed.), Impotence diagnosis and management of erectile dysfunction (pp. 213-228). Philadelphia: Saunders.

Goldstein, I., Krane, R.J., Greenfield, A.J., & Padma-Nathan, H. (1990). Vascular diseases of the penis: Impotence and priapism. In H.M. Pollack (Ed.), Clinical urography Volume 3 (pp. 2231-2252). Philadelphia: Saunders.

King, B.F., Lewis, R.W., & McKusick, M.A. (1994). Radiologic evaluation of impotence. In A.H. Bennett (Ed.), Impotence diagnosis and management of erectile dysfunction (pp. 5291). Philadelphia: Saunders.

Lue, T.F., & Donatucci, C.F. (1994). Dysfunction of the venoocclusive mechanism. in A.H. Bennett (Ed.), Impotence diagnosis and management of erectile dysfunction (pp. 197-204). Philadelphia: Saunders.

NIH Consensus Development Panel on Impotence. (1993). Impotence. JAMA, 270, 83-90.

Sattar, A.A., Wery, D., Coizariba, J., Raviv, C., Schulman, C., & Wespes, E. (1996). Correlation of nocturnal penile tumescence monitoring, duplex ultrasonography, and infusion cavernosometry for the diagnosis of erectile dysfunction. Journal of Urology, 155, 1274-1276.

Smoking Cessation Guidelines Panel. (1996, April). Smoking cessation. AHCPR Pub No.96-0692. Rockville, MD: Agency for Health Care Policy and Research, Public Health Service, U.S. Department of Health and Human Services.

Additional Readings

Meredith, C.E. (1995). Erectile dysfunction. In K.A. Karlowicz (Ed.), Urologic nursing principles and practice (pp. 332-359). Philadelphia: Saunders.

Montague, D.K., Barada, J.H., Balker, AM., Levine, L.A., Nadig, P.W., Roehrborn, C.G., Sharlip, I.E., & Bennett, A.H. (1996). Clinical guidelines panel on erectile dysfunction: Summary report on the treatment of organic erectile dysfunction. Journal of Urology, 156, 207-211.

Figure 1.

Equilibrium Pressure

Inflow (CASOP) - Outflow (CVOF) = Equilibrium

120 mmHg - 30 mmHg = 90 mmHg
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Title Annotation:erectile dysfunction diagnosis
Author:Ford, Peggy L.
Publication:Urologic Nursing
Geographic Code:1USA
Date:Aug 1, 2000
Words:2217
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