Acid-Base Status: Enter values and click 'Interpret ABG'.
Oxygenation Status:
function calculateABG() {
var pH = parseFloat(document.getElementById("phValue").value);
var paco2 = parseFloat(document.getElementById("paco2Value").value);
var hco3 = parseFloat(document.getElementById("hco3Value").value);
var pao2 = parseFloat(document.getElementById("pao2Value").value);
var sao2 = parseFloat(document.getElementById("sao2Value").value);
var resultText = "";
var oxygenationText = "";
// — Validate Inputs —
if (isNaN(pH) || isNaN(paco2) || isNaN(hco3)) {
document.getElementById("abgResult").innerHTML = "Acid-Base Status: Please enter valid numbers for pH, PaCO2, and HCO3.";
document.getElementById("oxygenationResult").innerHTML = "Oxygenation Status: ";
return;
}
// — pH Status —
var pH_status = "normal";
if (pH 7.45) {
pH_status = "alkalotic";
}
// — PaCO2 Status (Respiratory) —
var paco2_status = "normal";
if (paco2 45) {
paco2_status = "acidic"; // High PaCO2 causes acidosis
}
// — HCO3 Status (Metabolic) —
var hco3_status = "normal";
if (hco3 26) {
hco3_status = "alkalotic"; // High HCO3 causes alkalosis
}
// — Primary Disorder and Compensation —
if (pH_status === "acidic") { // Acidemia
if (paco2_status === "acidic" && hco3_status === "normal") {
resultText = "Uncompensated Respiratory Acidosis";
} else if (paco2_status === "acidic" && hco3_status === "alkalotic") {
resultText = "Partially Compensated Respiratory Acidosis";
} else if (hco3_status === "acidic" && paco2_status === "normal") {
resultText = "Uncompensated Metabolic Acidosis";
} else if (hco3_status === "acidic" && paco2_status === "alkalotic") {
resultText = "Partially Compensated Metabolic Acidosis";
} else if (paco2_status === "acidic" && hco3_status === "acidic") {
resultText = "Mixed Respiratory and Metabolic Acidosis";
} else {
resultText = "Complex Acid-Base Disorder (Acidemia)";
}
} else if (pH_status === "alkalotic") { // Alkalemia
if (paco2_status === "alkalotic" && hco3_status === "normal") {
resultText = "Uncompensated Respiratory Alkalosis";
} else if (paco2_status === "alkalotic" && hco3_status === "acidic") {
resultText = "Partially Compensated Respiratory Alkalosis";
} else if (hco3_status === "alkalotic" && paco2_status === "normal") {
resultText = "Uncompensated Metabolic Alkalosis";
} else if (hco2_status === "alkalotic" && paco2_status === "acidic") { // Corrected typo hco2_status to hco3_status
resultText = "Partially Compensated Metabolic Alkalosis";
} else if (paco2_status === "alkalotic" && hco3_status === "alkalotic") {
resultText = "Mixed Respiratory and Metabolic Alkalosis";
} else {
resultText = "Complex Acid-Base Disorder (Alkalemia)";
}
} else { // Normal pH (7.35-7.45)
if (paco2_status === "normal" && hco3_status === "normal") {
resultText = "Normal ABG";
} else if (paco2_status === "acidic" && hco3_status === "alkalotic") {
if (pH < 7.40) { // Closer to acidic side of normal
resultText = "Fully Compensated Respiratory Acidosis";
} else { // Closer to alkalotic side of normal
resultText = "Fully Compensated Metabolic Alkalosis";
}
} else if (paco2_status === "alkalotic" && hco3_status === "acidic") {
if (pH < 7.40) { // Closer to acidic side of normal
resultText = "Fully Compensated Metabolic Acidosis";
} else { // Closer to alkalotic side of normal
resultText = "Fully Compensated Respiratory Alkalosis";
}
} else {
resultText = "Normal pH with unclassified abnormalities (consider mixed disorder)";
}
}
// — Oxygenation Status —
if (!isNaN(pao2) && !isNaN(sao2)) {
if (pao2 < 80 && sao2 < 95) {
oxygenationText = "Hypoxemia (PaO2 < 80 mmHg and SaO2 < 95%)";
} else if (pao2 < 80) {
oxygenationText = "Hypoxemia (PaO2 < 80 mmHg)";
} else if (sao2 < 95) {
oxygenationText = "Hypoxemia (SaO2 < 95%)";
}
else {
oxygenationText = "Normal Oxygenation";
}
} else if (!isNaN(pao2)) {
if (pao2 < 80) {
oxygenationText = "Hypoxemia (PaO2 < 80 mmHg)";
} else {
oxygenationText = "Normal PaO2";
}
} else if (!isNaN(sao2)) {
if (sao2 < 95) {
oxygenationText = "Hypoxemia (SaO2 < 95%)";
} else {
oxygenationText = "Normal SaO2";
}
} else {
oxygenationText = "Oxygenation status not assessed (missing PaO2/SaO2)";
}
document.getElementById("abgResult").innerHTML = "Acid-Base Status: " + resultText;
document.getElementById("oxygenationResult").innerHTML = "Oxygenation Status: " + oxygenationText;
}
Understanding Arterial Blood Gases (ABGs)
Arterial Blood Gas (ABG) analysis is a critical diagnostic tool used in medicine to assess a patient's acid-base balance and oxygenation status. It involves taking a blood sample from an artery, typically the radial artery in the wrist, and measuring various parameters.
Key Components of an ABG:
pH: This measures the acidity or alkalinity of the blood. A normal pH range is typically 7.35 to 7.45.
pH < 7.35 indicates Acidemia (too much acid).
pH > 7.45 indicates Alkalemia (too much base).
PaCO2 (Partial Pressure of Carbon Dioxide): This reflects the respiratory component of acid-base balance. CO2 is an acid, and its levels are primarily regulated by the lungs. A normal range is 35 to 45 mmHg.
High PaCO2 (> 45 mmHg) indicates respiratory acidosis.
HCO3 (Bicarbonate): This represents the metabolic component of acid-base balance. Bicarbonate is a base, and its levels are primarily regulated by the kidneys. A normal range is 22 to 26 mEq/L.
High HCO3 (> 26 mEq/L) indicates metabolic alkalosis.
PaO2 (Partial Pressure of Oxygen): This measures the amount of oxygen dissolved in the arterial blood, indicating the efficiency of oxygen transfer from the lungs to the blood. A normal range is typically 80 to 100 mmHg (at sea level).
SaO2 (Oxygen Saturation): This measures the percentage of hemoglobin carrying oxygen. It reflects how well oxygen is being delivered to the tissues. A normal range is typically 95% to 100%.
Basic ABG Interpretation Steps:
Assess pH: Determine if the patient is acidemic, alkalemic, or has a normal pH. This sets the overall acid-base state.
Assess PaCO2: Look at the respiratory component. Does it explain the pH abnormality? (e.g., high PaCO2 with low pH suggests respiratory acidosis).
Assess HCO3: Look at the metabolic component. Does it explain the pH abnormality? (e.g., low HCO3 with low pH suggests metabolic acidosis).
Determine Primary Disorder: Identify which component (respiratory or metabolic) is primarily causing the pH imbalance.
Check for Compensation: If the pH is abnormal, see if the "other" system is trying to bring the pH back to normal.
Uncompensated: The compensating system is normal.
Partially Compensated: The compensating system is abnormal, but the pH is still outside the normal range.
Fully Compensated: Both systems are abnormal, but the pH has returned to the normal range (though often closer to the acidic or alkalotic end of normal).
Evaluate Oxygenation: Review PaO2 and SaO2 to determine if the patient is hypoxemic.
How to Use the ABG Interpretation Calculator:
Enter the pH, PaCO2, and HCO3 values from your ABG report into the respective fields. Optionally, you can also enter PaO2 and SaO2 to get an assessment of oxygenation status. Click the "Interpret ABG" button, and the calculator will provide an interpretation of the acid-base balance and oxygenation status based on standard clinical ranges.
Examples:
Example 1 (Normal ABG): pH 7.40, PaCO2 40 mmHg, HCO3 24 mEq/L, PaO2 95 mmHg, SaO2 98%. Result: Normal ABG, Normal Oxygenation.
Disclaimer: This ABG Interpretation Calculator is for educational purposes only and should not be used as a substitute for professional medical advice, diagnosis, or treatment. Always consult with a qualified healthcare professional for any health concerns or before making any decisions related to your health or treatment.