ACIDITY AND ALKALINITY OF BODY SYSTEMS

 

INTRODUCTION: Acidosis also known as excess acid and alkalosis known as excess base in the human body, are not diseases but are symptoms of an underlying disorder. Acidic and basic agents may be administered to rapidly correct pH imbalances in body fluids, supporting the patient’s vital functions while the underlying disease is being treated. The degree of acidity or alkalinity of a solution is measured by its pH and a pH of 7.0 is defined as neutral, above 7.0 as basic or alkaline, and below 7.0 as acidic.

THE HUMAN BODY HOMEOSTASIS: To maintain homeostasis, the pH of plasma and most body fluids must be kept within the narrow range of 7.35 to 7.45. Nearly all proteins and enzymes in the body function optimally within this narrow range of pH values. A few enzymes, most notably those in the digestive tract, require pH values outside the 7.35 to 7.45 range to function properly. The body generates significant amounts of acid during normal metabolic processes. Without sophisticated means of neutralizing these metabolic acids, the overall pH of body fluids would quickly fall below the normal range. Buffers are chemicals that help maintain normal body pH by neutralizing strong acids and bases.

BODY BUFFERS: The two primary buffers in the body are bicarbonate ions and phosphate ions. The body uses two mechanisms to remove acid. The carbon dioxide (CO2) produced during body metabolism is an acid efficiently removed by the lungs during exhalation. The kidneys remove excess acid in the form of hydrogen ion (H⁺) by excreting it in the urine. If retained in the body, CO2 and/or H⁺ would lower body pH. Thus, the lung and the kidneys collaborate in the removal of acids to maintain normal acid–base balance.

PHARMACOTHERAPY OF ACIDOSIS: Acidosis occurs when the pH of the plasma falls below 7.35, which is confirmed by measuring arterial pH, partial pressure of carbon dioxide (PCO2 ), and plasma bicarbonate levels. In that case, diagnosis must differentiate between respiratory etiology and metabolic or renal etiology. It should be noted that, occasionally the cause has mixed respiratory and metabolic components. The most profound symptoms of acidosis affect the central nervous system (CNS) and include lethargy, confusion, and CNS depression leading to coma. A deep, rapid respiration rate indicates an attempt by the lungs to rid the body of excess acid. In patients with acidosis, the therapeutic goal is to quickly reverse the level of acids in the blood. The preferred treatment for acute acidosis is to administer infusions of sodium bicarbonate. Bicarbonate ion acts as a base to quickly neutralize acids in the blood and other body fluids. The patient must be carefully monitored during infusions because this drug can overcorrect the acidosis, causing blood pH to turn alkaline. Sodium citrate, sodium lactate, and sodium acetate are alternative alkaline agents sometimes used in place of bicarbonate.

RELATED;

1. ACID, BASES AND BODY BUFFERS

2. BODY FLUIDS

3. ANATOMY AND PHYSIOLOGY

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