Articles on Medical Diseases and Conditions

Entries for October, 2009

Effects of Adrenal Cortex Dysfunction

Certain adrenal cortex hormones control sodium retention and potassium excretion. Aldosterone is the most powerful of these hormones, but cortisone and hydrocortisone also have some effect. In primary Addison’s disease there are variable degrees of adrenal cortex destruction. This results in deficiency of both aldosterone and cortisol, thereby severely decreasing normal salt-retaining hormone influence on […]

Hyponatremic Depletional Syndromes

In protracted and severe vomiting, as occurs with pyloric obstruction or stenosis, gastric fluid is lost in large amounts and a hypochloremic (acid-losing) alkalosis develops. Gastric contents have a relatively low sodium content and water loss relatively exceeds electrolyte loss. Despite relatively low electrolyte content, significant quantities of electrolytes are lost with the fluid, leading […]

Hyponatremia. Iatrogenic Sources of Hyponatremia

Diuretic therapy and administration of IV hypotonic fluids (dextrose in water or half-normal saline) form very important and frequent etiologies for hyponatremia, either as the sole agent or superimposed on some condition predisposing to hyponatremia. In several studies of patients with hyponatremia, diuretic use was considered to be the major contributing factor or sole etiology […]

Serum Sodium Abnormalities

The most frequent electrolyte abnormalities, both clinically and as reflected in abnormal laboratory values, involve sodium. This is true because sodium is the most important cation of the body, both from a quantitative standpoint and because of its influence in maintaining electric neutrality. The most common causes of low or high serum sodium values are […]

Effect of Physiologic Patient Variation on Blood Gas Interpretation

There is a surprising degree of fluctuation in blood gas values in normal persons and in stabilized sick persons. In one study of normal persons using arterialized capillary blood, changes of at least 10% in bicarbonate or total CO2, 15% in PCO2, and 170% in base excess were required to exceed normal day-to-day variation. In […]

Newborn and Neonatal Blood Gas Measurement

A number of studies have found that umbilical cord arterial pH is the best available indicator of fetal acidosis, which would suggest intrauterine fetal hypoxia. Arterial pH was found to be more accurate than arterial PCO2, PO2, cord venous pH, or Apgar score. Although there is some disagreement regarding cord arterial pH reference range, a […]

Surgical Treatments for Arrhythmias

In  addition  to  drugs  and  nonsurgical  procedures,  several types  of surgery can restore  your heart’s rhythm.  Implantation of a pacemaker can treat bradycardia (slow heartbeat);  an internal  cardioverter- de?brillator can correct more serious arrhythmias; or a procedure called maze surgery can be performed  on some people with atrial ?brillation. Pacemakers A pacemaker  is a battery-powered […]

Noninvasive Measurement of PCO2, PO2, and Oxygen Saturation

There are now several ways to measure carbon dioxide and oxygen in blood without drawing a blood sample. The two most popular methods at present are transcutaneous electrode systems and pulse oximetry. Both systems can provide continuous readings. The transcutaneous systems use PCO2 and PO2 electrodes similar to those of standard arterial blood gas analysis […]

Nonsurgical Treatments for Arrhythmias

Great  advances have been made in nonsurgical  treatments for certain types of arrhythmias. These techniques,  including ablation and electrical cardioversion,  may restore  normal heart rhythms,  reduce or elimi- nate symptoms,  and reduce  or eliminate  the need for medications  or surgical procedures (such as implantation of a pacemaker or an internal cardioverter-de?brillator). Catheter Ablation Catheter ablation […]

Blood Lactate

Under conditions of adequate or near-adequate tissue oxygenation, glucose is metabolized for energy production using the aerobic metabolic pathway that converts glucose metabolic products to pyruvate that is, in turn, metabolized in the citric acid (Krebs) cycle. Under conditions of severe tissue hypoxia, aerobic metabolism cannot function properly, and glucose metabolic products at the pyruvate […]