V. Runak. Winona State University.

O2 in blood and air entering the lungs (8) or Imaging Techniques Are Also Used for O2 output via pulmonary veins O2 input via pulmonary Measuring Cardiac Output artery O2 added by respiration (9) A variety of other techniques order aldactone 100 mg visa, many of which employ im- The O2 output via the pulmonary veins is equal to the aging modalities 100mg aldactone for sale, can be used to measure or estimate car- pulmonary vein O2 content multiplied by the cardiac out- diac output. Because O2 is neither added nor subtracted from the heart to estimate the difference between end-dias- the blood as it passes from the pulmonary veins through the tolic and end-systolic volumes. This difference gives left heart to the systemic arteries, the O2 output via pul- stroke volume and, with heart rate, allows calculation of monary veins is also equal to the arterial O2 content (aO2) cardiac output. Similarly, O2 input via the pulmonary artery is equal to mixed venous blood Radionuclide Techniques. In radionuclide tech- oxygen input to the right heart and is mixed venous blood niques, a radioactive substance (usually technetium-99) O content (v–O ) multiplied by the cardiac output (CO). By substitu- 2 The radiation (gamma rays) emitted by the large pool(s) tion in equation 9, of blood in the cardiac chambers is measured using a spe- – ˙ cially designed gamma camera. The emitted radiation is (CO) (aO2) [(CO) (vO2)] VO2 (10) proportional to the amount of technetium bound to the which rearranges to blood (easily determined by sampling the tagged blood) ˙ – and the volume of blood in the heart. Using computer- CO VO2/(aO2 vO2) (11) ized analysis, the amount of radiation emitted by the left Systemic arterial blood oxygen content, pulmonary ar- (or right) ventricle during various portions of the cardiac terial (mixed venous) blood oxygen content, and oxygen cycle can be determined (Fig. The amount Q Cardiac output O consumption 2 250 mL/min O2 consumption Q A–V 250 mL O2/min Q 0. In diastole (C), white arrows in A show the boot-shaped left ventricle during car- the ventricle is large and the wall is thinned; during systole (D), the diac diastole when it is maximally filled with radionuclide-labeled wall thickens and the ventricular size decreases. In B, much of the apex appears to be missing (white arrows) (cine) computed tomography. The ventricular size and wall thick- because cardiac systole has caused the blood to be ejected as the in- ness can be assessed during diastole and systole, and the change in traventricular volume decreases. C and D, Two-dimensional ventricular size can be used to calculate cardiac output. Echocardiography (ultrasound car- determined by comparing the amount of radiation meas- diography) provides two-dimensional, real-time images of ured at the end of systole with that at the end of diastole; the heart.

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If the patient has a symptomatic UTI discount aldactone 25mg with amex, the entire system must be changed and a urine culture obtained purchase 25mg aldactone fast delivery. A person with MS may still experience urinary incontinence with an indwelling catheter. In this instance, the indication is not to increase the size of the catheter or balloon, but rather to use anticholinergic/antimuscarinic medications to decrease urinary tract spasticity. Suprapubic catheters are sometimes an alternative to long-term urethral catheters. These may be helpful in male patients and in women who have developed severe urethral irritation secondary to an indwelling Foley catheter. Sphincterectomy may be recommended for very disabled male patients who experience intractable hesitancy and retention. Anticholinergic medications and an external condom catheter can be combined to manage bladder activity. Some female patients with small-capacity bladder may benefit from a laparoscopic procedure that includes bladder augmenta- tion with a continent diversion. Diversion procedures including cystostomy or transurethral resection, which provides a clear passageway for the urine to flow freely. Chapter 14 Bowel Elimination and Continence Objectives: Upon completion of this chapter, the learner will identify: The common pathophysiology of upper motor neuron bowel, lower motor neuron bowel, uninhibited neurogenic bowel, and motor paralytic bowel as seen in MS Goals for establishing bowel control with MS Common nursing interventions in managing a neurogenic bowel A comprehensive care plan for gastrointestinal complications The long-term implications of neurogenic bowel dysfunction Altered bowel function may occur whenever the central nervous system (CNS) has been impaired. When disease or disability results in altered bowel control, incontinence may become as devastating a problem as the disease itself. Control of incontinence and prevention of constipation and diarrhea are possible through an effective bowel program, which requires a knowledge of normal and altered bowel physiology as well as an in-depth assessment of bowel function.

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The scanner generates pictures by analyzing how water molecules react to electrical impulses in this strong magnetic environment purchase aldactone 25mg with amex. When a person lies in the magnetic field on an MR unit buy aldactone 25 mg fast delivery, protons align with the axis of the magnet. When the pulse is turned off, the protons return to their previ- ous states. MS lesions have T1 and T2 relaxation properties because of free water associated with edema and inflammation and because of tissue destruction. Gadopentetate (gadolinium) is a contrast agent to identify active MS lesions. MS scans should include the entire brain, although MS lesions are most frequent in the periventricular region. T1W or T1 black holes are subsets of chronic T2 lesions that appear hypointense on T1W images and have extensive tissue destruction. It is likely that hypointense lesions on T1-weighted images represent the more disabling lesions and that these lesions correlate with persistent neurologic deficit in people with MS. Corpus callosum lesions (arrows) occur along the inner (deep) callosal surfaces and have irregular outer borders, which do not follow the expect- ed contours of the nerve fibers. The primary use of MRI in MS is to confirm the diagnosis and rule out other possible conditions. MRI may also be able to predict the course of MS since research has shown that people who have MRI activity repre- CHAPTER 7: MAGNETIC RESONANCE IMAGING 29 senting new MS lesions will continue to have MRI activity over subsequent months and years. MRI may also be used to monitor the effectiveness of drugs in clinical trials. MRI lesions may precede overt symptoms as seen in studies of the natural history of MS. MRI has provided valuable insights into the course of the ill- ness and has helped to identify new therapies that have at least a partial effect on disease activity. This enhancement usually subsides in 3 to 6 weeks, leaving a “white spot” on the MRI image.