Arterial Blood Gas and Acid-Base Balance Lecture

These flashcards cover the fundamentals of Arterial Blood Gas (ABG) procedures, normal ranges for pH, oxygen, and carbon dioxide, the buffer equation, and the four primary acid-base imbalances.

Arterial Blood Gas (ABG)

A procedure where blood is drawn from an artery, commonly in the wrist, to measure oxygen, carbon dioxide, and pH levels.

Warfarin

A specific blood thinner mentioned that must be screened for before performing an ABG procedure.

Modified Allen Test

A test to assess the blood supply to the hand where the patient makes a tight fist while the practitioner presses on both sides of the wrist.

Stat Lab

A laboratory test that must be run immediately, such as an ABG, because gases can escape if the syringe is not capped and put on ice quickly.

pH

The negative logarithm of the hydrogen concentration, representing the acidity or alkalinity of the blood.

Normal Arterial pH Range

The normal range for arterial blood is $7.35 \text{ to } 7.45$.

Acidosis

A state where the pH is below $7.35$; a level of $6.9$ is defined as often fatal.

Alkalosis

A state where the pH is above $7.45$; a level of $7.8$ is defined as often fatal.

Buffer system

The fastest acting acid-base balancing system that works instantaneously to maintain internal neutrality.

Respiratory System (Acid-Base Role)

A system that assists in balancing pH by adjusting breathing, starting to work within $1 \text{ to } 3 \text{ minutes}$.

Renal System (Acid-Base Role)

The slowest-acting system for pH balance, taking several hours to several days to compensate through the kidneys.

Buffer Equation

The chemical equation $H_2O + CO_2 \rightleftharpoons H_2CO_3 \rightleftharpoons H^+ + HCO_3^-$ that runs in every red blood cell.

Carbonic Acid ($H_2CO_3$)

A very weak acid that acts as a 'transformer' in the buffer equation, middle-grounding the respiratory and metabolic sides.

Ammonium Ion

The form in which hydrogen ions are dumped by the kidneys into the urine during acidosis.

PaO2

Partial pressure of oxygen in arterial blood, with a normal range of $80 \text{ to } 100 \, mmHg$.

Torr

A unit of measurement for pressure where $1 \, mmHg = 1 \, \text{Torr}$.

PaCO2

Partial pressure of carbon dioxide in arterial blood, with a normal range of $35 \text{ to } 45 \, mmHg$.

Bicarbonate ($HCO_3^-$)

The metabolic component of the buffer equation, with a normal range of $22 \text{ to } 26$.

Respiratory Acidosis

A condition characterized by high $CO_2$ (greater than $45 \, mmHg$) that acts like an acid, often caused by hypoventilation.

Respiratory Alkalosis

A condition resulting from low $CO_2$ (less than $35 \, mmHg$), often caused by hyperventilation syndrome.

Hyperventilation Syndrome Symptoms

Includes feeling air hungry, numbness and tingling around the mouth, chest pain, and carpal pedal spasms (lobster claws).

Metabolic Acidosis

An imbalance caused by high hydrogen ions or loss of bicarbonate, frequently exemplified by Diabetic Ketoacidosis (DKA).

The 'Big Three' Poly Symptoms

Polyuria (excessive urination), Polydipsia (excessive thirst), and Polyphagia (excessive hunger), which are classic tip-offs for DKA.

Kussmaul Respiration

A rapid, full, and deep breathing pattern used by the body to blow off $CO_2$ to compensate for metabolic acidosis.

Metabolic Alkalosis

A condition of excess alkalinity, often caused by ingestions such as an overdose of bicarbonate-containing antacids (e.g., Tums).

Apnea (in Alkalosis)

A potential but dangerous respiratory response to metabolic alkalosis where the body stops breathing to retain $CO_2$.