Abg analysis from basic to clinic application

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"arterial blood gas" AND "acid-base" interpretation

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Arterial Blood Gas (ABG) Analysis: Basic to Clinical Application

1. What Is an ABG and Why Does It Matter?

An arterial blood gas measures pH, PaCO2, PaO2, HCO3-, and often base excess (BE) from an arterial sample. It is the best single tool for assessing oxygenation, ventilation, and acid-base status simultaneously. ABG analysis is relevant in virtually every critically ill patient - acid-base disorders occur in 51-56% of hospitalized patients.

2. Normal ABG Values

Parameter	Normal Range	Meaning
pH	7.35 - 7.45	Acidity/alkalinity of blood
PaCO2	35 - 45 mmHg	Ventilatory (respiratory) component
PaO2	80 - 100 mmHg	Oxygenation
HCO3-	22 - 26 mEq/L	Metabolic/renal component
Base Excess (BE)	-2 to +2 mEq/L	Net metabolic acid-base deviation
SaO2	95 - 100%	Hemoglobin oxygen saturation

pH < 7.35 = acidemia | pH > 7.45 = alkalemia

3. The Henderson-Hasselbalch Equation (The Core Physiology)

$$\text{pH} = 6.1 + \log_{10}\left(\frac{[\text{HCO}_3^-]}{0.03 \times \text{PaCO}_2}\right)$$

The numerator (HCO3-) is controlled by the kidneys (slow, days)
The denominator (PaCO2) is controlled by the lungs (fast, minutes)
Together they maintain pH at 7.40

Every day, the body produces ~10,000-15,000 mmol of volatile acid (CO2) and 50-100 mEq of nonvolatile acid. These are buffered in cells and ECF, then excreted via lungs and kidneys respectively.

4. The Four Primary Acid-Base Disorders

Disorder	pH	Primary Change	Compensation
Metabolic Acidosis	Low	↓ HCO3-	↓ PaCO2 (hyperventilation)
Metabolic Alkalosis	High	↑ HCO3-	↑ PaCO2 (hypoventilation)
Respiratory Acidosis	Low	↑ PaCO2	↑ HCO3- (renal retention)
Respiratory Alkalosis	High	↓ PaCO2	↓ HCO3- (renal excretion)

5. Compensation Formulas (Memorize These)

These formulas tell you what compensation is expected for a simple disorder. If measured values differ from predicted, a mixed disorder is present.

Metabolic Acidosis

Winter's Formula: PaCO2 = 1.5 × [HCO3-] + 8 ± 2 mmHg

Compensation begins within 12-24 hours
Alternatively: ↓PaCO2 = 1.1 × ↓[HCO3-]

Metabolic Alkalosis

PaCO2 = 0.7 × [HCO3-] + 20 ± 5 mmHg

Compensation within 24-48 hours
Alternatively: ↑PaCO2 = 0.75 × ↑[HCO3-]

Respiratory Acidosis

Acute: Δ[HCO3-] = +1 mEq/L per 10 mmHg rise in PaCO2
Chronic: Δ[HCO3-] = +4 mEq/L per 10 mmHg rise in PaCO2
Compensation develops over 48-96 hours

Respiratory Alkalosis

Acute: Δ[HCO3-] = -2 mEq/L per 10 mmHg fall in PaCO2
Chronic: Δ[HCO3-] = -4 to -5 mEq/L per 10 mmHg fall in PaCO2
Compensation develops over 48-96 hours

6. Systematic Step-by-Step ABG Interpretation

Step 1: Is the Patient Acidemic or Alkalemic?

pH < 7.35 → acidemia
pH > 7.45 → alkalemia
pH 7.35-7.45 → normal (but a mixed disorder may still exist!)

Step 2: Identify the Primary Disorder

PaCO2 high + low pH → Respiratory Acidosis
PaCO2 low + high pH → Respiratory Alkalosis
HCO3- low + low pH → Metabolic Acidosis
HCO3- high + high pH → Metabolic Alkalosis

The primary disorder is the one that matches the direction of the pH change.

Step 3: Is Compensation Appropriate?

Apply the relevant compensation formula above. If the measured value falls outside the expected range:

More acidotic than expected → additional metabolic acidosis
More alkalotic than expected → additional metabolic alkalosis

Step 4: Calculate the Anion Gap (if metabolic acidosis present)

AG = [Na+] - ([Cl-] + [HCO3-])

Normal: 8-12 mEq/L (or up to 13 with albumin correction)
Correct for albumin: For every 1 g/dL albumin below 4 g/dL, add 2.5 mEq/L to AG

High AG Metabolic Acidosis - MUDPILES mnemonic:

Methanol
Uremia
DKA (and other ketoacidosis)
Propylene glycol / Paraldehyde
Isoniazid / Iron
Lactic acidosis
Ethylene glycol
Salicylates

Normal AG (Hyperchloremic) Metabolic Acidosis:

Diarrhea (GI bicarbonate loss)
Renal tubular acidosis (RTA)
Carbonic anhydrase inhibitors (acetazolamide)
Saline resuscitation (dilutional)
Ureteral diversion

Step 5: Delta-Delta Ratio (for High AG Acidosis)

ΔAG / ΔHCO3- = (measured AG - 12) / (24 - measured HCO3-)

Ratio	Interpretation
< 1	Mixed: high AG + normal AG acidosis
1 - 2	Pure high AG metabolic acidosis
> 2	Mixed: high AG acidosis + metabolic alkalosis

7. Physiologic Consequences of Extreme Derangements

Severe Acidemia (pH < 7.2)

System	Effect
Cardiovascular	Impaired myocardial contractility, ↓ cardiac output, ↑ pulmonary vascular resistance, arrhythmias, reduced catecholamine responsiveness
Respiratory	Hyperventilation, dyspnea, respiratory muscle fatigue
Metabolic	Insulin resistance, ↓ ATP synthesis, hyperkalemia, protein catabolism
Cerebral	Altered mental status, coma, inhibited cellular metabolism

Severe Alkalemia (pH > 7.6)

System	Effect
Cardiovascular	Arteriolar constriction, ↓ coronary flow, arrhythmias, left shift of O2 dissociation curve
Respiratory	Hypoventilation
Metabolic	Hypokalemia, ↓ ionized Ca2+, Mg2+, and phosphate
Cerebral	↓ Cerebral blood flow, tetany, seizures, delirium, coma

8. Oxygenation Assessment

A-a Gradient (Alveolar-Arterial Oxygen Difference)

PAO2 = (FiO2 × [Patm - PH2O]) - (PaCO2 / R)

On room air at sea level: PAO2 = 150 - (PaCO2/0.8)
A-a gradient = PAO2 - PaO2
Normal: < 10-15 mmHg (increases with age: ~age/4 + 4)

Condition	PaO2	PaCO2	A-a Gradient
Hypoventilation	Low	High	Normal
V/Q mismatch	Low	Low/Normal	Elevated
Diffusion defect	Low	Normal/Low	Elevated
Right-to-left shunt	Low	Low	Elevated (doesn't correct with O2)

P/F Ratio (Oxygenation Index)

P/F = PaO2 / FiO2

Normal: > 400 mmHg
Mild ARDS: 200-300
Moderate ARDS: 100-200
Severe ARDS: < 100

9. Mixed Acid-Base Disorders

A mixed disorder occurs when two or more primary disturbances coexist. Key clues:

pH is normal but PaCO2 and HCO3- are both abnormal
Compensation exceeds or falls short of expected range
Delta-delta ratio is outside 1-2

Classic clinical example - Salicylate toxicity (from Rosen's Emergency Medicine):

ABG: pH 7.47 / PaCO2 25 / PaO2 180
Step 1: pH 7.47 → alkalemia
Step 2: PaCO2 25 → respiratory alkalosis
Step 3: Predicted pH for this PaCO2 = 7.40 + [(40-25)/10 × 0.08] = 7.52
Measured pH (7.47) is lower than predicted (7.52) → concurrent metabolic acidosis
Final diagnosis: Mixed respiratory alkalosis + metabolic acidosis

Another example: An alcoholic patient with vomiting develops metabolic alkalosis (pH 7.55, HCO3- 40), then develops superimposed alcoholic ketoacidosis. The pH normalizes to 7.40, HCO3- 25, PaCO2 40 - all "normal" values - but the AG is 25. This demonstrates a mixed metabolic alkalosis + metabolic acidosis that is invisible without AG calculation.

10. Potassium and Acid-Base

Plasma K+ and pH are closely linked:

Metabolic acidosis → K+ shifts out of cells → hyperkalemia
For each ↓0.10 in pH, K+ rises ~0.6 mEq/L
Metabolic alkalosis → K+ shifts into cells → hypokalemia
Hypokalemia itself maintains metabolic alkalosis by enhancing H+-K+-ATPase in the collecting duct and increasing NH4+ excretion

DKA and lactic acidosis are exceptions - they often present with low total body K+ despite acidemia due to osmotic diuresis and poor intake.

11. Clinical Applications by Setting

ICU / Critical Care

Serial ABGs guide mechanical ventilation settings (target PaCO2, pH)
ABG is superior to pulse oximetry alone - SpO2 cannot detect hypercapnia or acid-base disorders
In septic shock, lactic acidosis drives high-AG metabolic acidosis; pH < 7.2 carries increased mortality
BICAR-ICU trial: NaHCO3 showed no overall mortality benefit in severe metabolic acidemia but did reduce need for renal replacement therapy in patients with AKI

Respiratory Failure

ABG distinguishes Type 1 (hypoxemic, PaO2 < 60, normal PaCO2) from Type 2 (hypercapnic, PaCO2 > 45) respiratory failure
COPD exacerbation: chronic compensated respiratory acidosis with elevated HCO3-; acute decompensation shows pH fall without proportional HCO3- rise
Use BE + PaCO2 trend to guide NIV/intubation decisions

Metabolic Emergencies

DKA: High-AG metabolic acidosis, pH can be 6.9-7.2, hyperkalemia, acetone on breath
HHS: Minimal acidosis (if any), extreme hyperglycemia, severe dehydration
Lactic acidosis: Sepsis, mesenteric ischemia, metformin overdose, type B causes
Hyperchloremic acidosis: Aggressive saline resuscitation, diarrhea, RTA

Poisoning/Toxicology

Salicylates: Mixed respiratory alkalosis + metabolic acidosis (classic)
Methanol/ethylene glycol: High AG acidosis + elevated osmol gap
Opioids: Respiratory acidosis with hypoxia
TCA overdose: Mixed respiratory and metabolic acidosis

Perioperative/Anesthesia

Goal-directed fluid therapy: Excessive 0.9% saline causes hyperchloremic metabolic acidosis; balanced crystalloids (LR, PlasmaLyte) reduce this risk
Post-cardiac surgery: Metabolic alkalosis from citrate in blood products, diuretics
Permissive hypercapnia in laparoscopic surgery (CO2 pneumoperitoneum) → respiratory acidosis

12. Clinical Clues Without ABG

Even serum electrolytes alone can hint at acid-base disorders:

Elevated AG on chemistry panel → high-AG metabolic acidosis even without blood gas
Low Cl- + high HCO3- → metabolic alkalosis (vomiting, diuretics)
Physical exam: tetany (alkalemia), Kussmaul breathing (metabolic acidosis), cyanosis (respiratory failure)
Drug history: acetazolamide → metabolic acidosis; loop/thiazide diuretics → metabolic alkalosis

13. Three-Step Clinical Algorithm (Quick Reference)

1. Is the patient acidemic or alkalemic?
   ├── pH < 7.35 → Acidemia
   └── pH > 7.45 → Alkalemia

2. Is the primary disorder metabolic or respiratory?
   ├── pH↓ + PaCO2↑ → Respiratory Acidosis
   ├── pH↑ + PaCO2↓ → Respiratory Alkalosis
   ├── pH↓ + HCO3-↓ → Metabolic Acidosis
   └── pH↑ + HCO3-↑ → Metabolic Alkalosis

3. Is compensation appropriate?
   └── If not → Mixed disorder present
       ├── If high-AG acidosis: Calculate delta-delta ratio
       └── Interpret oxygenation: P/F ratio, A-a gradient

Sources

Barash, Cullen & Stoelting's Clinical Anesthesia, 9e - Chapters 16 (Acid-Base, Fluids, Electrolytes), pp. 1146-1155
Brenner and Rector's The Kidney - Chapter 16, Stepwise Approach to Acid-Base Disorders, pp. 700-705
Rosen's Emergency Medicine - Box 113.2, Three-Step ABG Algorithm, p. 2505
Recent review: Sanagustín MN & Osredkar J, "Blood gas analysis: Clinical applications, interpretation and future directions," Medicine International, 2026 [PMID: 41473681]
Practice guideline: Habib T et al., "Mastering blood gas interpretation: A practical guide for primary care providers," S Afr Fam Pract, 2025 [PMID: 40336441]

Create a quick reference PDF with compensation formulas and MUDPILES mnemonics

Reading File

Running Command

ls -la /home/daytona/workspace/

Running Command

mkdir -p /home/daytona/workspace/abg-reference

Writing File

~/abg-reference/generate_abg_pdf.py

from reportlab.lib.pagesizes import A4
from reportlab.lib import colors
from reportlab.lib.units import mm
from reportlab.platypus import (
    SimpleDocTemplate, Paragraph, Spacer, Table, TableStyle,
    HRFlowable, KeepTogether
)
from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle
from reportlab.lib.enums import TA_CENTER, TA_LEFT, TA_JUSTIFY
from reportlab.platypus import PageBreak

OUTPUT = "/home/daytona/workspace/abg-reference/ABG_Quick_Reference.pdf"

# ── Colour palette ─────────────────────────────────────────────────────────────
NAVY    = colors.HexColor("#1a2e4a")
TEAL    = colors.HexColor("#0d7377")
GOLD    = colors.HexColor("#f0a500")
LIGHT   = colors.HexColor("#eaf4f4")
RED_BOX = colors.HexColor("#c0392b")
GREEN   = colors.HexColor("#1a7a4a")
ACIDRED = colors.HexColor("#d32f2f")
ALKBLUE = colors.HexColor("#1565c0")
WHITE   = colors.white
GREY    = colors.HexColor("#f5f5f5")
MID_GREY= colors.HexColor("#cccccc")

doc = SimpleDocTemplate(
    OUTPUT,
    pagesize=A4,
    rightMargin=14*mm, leftMargin=14*mm,
    topMargin=14*mm, bottomMargin=14*mm,
    title="ABG Quick Reference",
    author="Orris Medical"
)

W = A4[0] - 28*mm   # usable width

# ── Styles ─────────────────────────────────────────────────────────────────────
base = getSampleStyleSheet()

def S(name, **kw):
    return ParagraphStyle(name, **kw)

TITLE_STYLE = S("title_s",
    fontSize=22, textColor=WHITE, fontName="Helvetica-Bold",
    alignment=TA_CENTER, spaceAfter=2)

SUB_STYLE = S("sub_s",
    fontSize=10, textColor=LIGHT, fontName="Helvetica",
    alignment=TA_CENTER, spaceAfter=0)

SEC_STYLE = S("sec_s",
    fontSize=11, textColor=WHITE, fontName="Helvetica-Bold",
    alignment=TA_LEFT, leftIndent=4, spaceAfter=0, spaceBefore=0)

BODY = S("body_s",
    fontSize=8.5, textColor=NAVY, fontName="Helvetica",
    leading=13, spaceAfter=2)

BOLD_BODY = S("bold_body",
    fontSize=8.5, textColor=NAVY, fontName="Helvetica-Bold",
    leading=13, spaceAfter=2)

FORMULA = S("formula",
    fontSize=9, textColor=TEAL, fontName="Helvetica-Bold",
    leading=14, leftIndent=8, spaceAfter=1)

MNEMONIC = S("mnemonic",
    fontSize=11, textColor=NAVY, fontName="Helvetica-Bold",
    leading=16, spaceAfter=1, alignment=TA_CENTER)

SMALL = S("small_s",
    fontSize=7.5, textColor=colors.HexColor("#555555"),
    fontName="Helvetica", leading=11)

FOOTER_STYLE = S("footer_s",
    fontSize=7, textColor=colors.HexColor("#888888"),
    fontName="Helvetica", alignment=TA_CENTER)

# ── Helper: Section header ─────────────────────────────────────────────────────
def section_header(text, bg=NAVY):
    data = [[Paragraph(text, SEC_STYLE)]]
    t = Table(data, colWidths=[W])
    t.setStyle(TableStyle([
        ("BACKGROUND", (0,0), (-1,-1), bg),
        ("TOPPADDING",    (0,0), (-1,-1), 5),
        ("BOTTOMPADDING", (0,0), (-1,-1), 5),
        ("LEFTPADDING",   (0,0), (-1,-1), 8),
        ("RIGHTPADDING",  (0,0), (-1,-1), 8),
        ("ROWBACKGROUNDS", (0,0), (-1,-1), [bg]),
    ]))
    return t

def hr():
    return HRFlowable(width="100%", thickness=0.5, color=MID_GREY, spaceAfter=4, spaceBefore=4)

# ══════════════════════════════════════════════════════════════════════════════
# BUILD STORY
# ══════════════════════════════════════════════════════════════════════════════
story = []

# ── TITLE BANNER ──────────────────────────────────────────────────────────────
banner_data = [[
    Paragraph("ABG Quick Reference Card", TITLE_STYLE),
    Paragraph("Arterial Blood Gas · Acid-Base · Oxygenation", SUB_STYLE),
]]
banner = Table([[Paragraph("ABG Quick Reference Card", TITLE_STYLE)],
                [Paragraph("Arterial Blood Gas  ·  Compensation Formulas  ·  MUDPILES", SUB_STYLE)]],
               colWidths=[W])
banner.setStyle(TableStyle([
    ("BACKGROUND", (0,0), (-1,-1), NAVY),
    ("TOPPADDING",    (0,0), (-1,-1), 10),
    ("BOTTOMPADDING", (0,0), (-1,-1), 10),
    ("LEFTPADDING",   (0,0), (-1,-1), 10),
    ("RIGHTPADDING",  (0,0), (-1,-1), 10),
]))
story.append(banner)
story.append(Spacer(1, 5))

# ── ROW 1: Normal Values + Henderson-Hasselbalch ─────────────────────────────
# Left: Normal Values table
nv_header = [
    [Paragraph("NORMAL ABG VALUES", S("nh", fontSize=9, fontName="Helvetica-Bold",
               textColor=WHITE, alignment=TA_CENTER))]
]
nv_rows = [
    ["pH",       "7.35 – 7.45"],
    ["PaCO₂",    "35 – 45 mmHg"],
    ["PaO₂",     "80 – 100 mmHg"],
    ["HCO₃⁻",   "22 – 26 mEq/L"],
    ["Base Excess", "−2 to +2 mEq/L"],
    ["SaO₂",     "95 – 100%"],
]
nv_style = TableStyle([
    ("BACKGROUND",    (0,0), (-1,0), TEAL),
    ("TEXTCOLOR",     (0,0), (-1,0), WHITE),
    ("FONTNAME",      (0,0), (-1,0), "Helvetica-Bold"),
    ("FONTSIZE",      (0,0), (-1,-1), 8.5),
    ("ROWBACKGROUNDS",(0,1), (-1,-1), [GREY, WHITE]),
    ("TEXTCOLOR",     (0,1), (-1,-1), NAVY),
    ("FONTNAME",      (0,1), (0,-1), "Helvetica-Bold"),
    ("GRID",          (0,0), (-1,-1), 0.4, MID_GREY),
    ("TOPPADDING",    (0,0), (-1,-1), 4),
    ("BOTTOMPADDING", (0,0), (-1,-1), 4),
    ("LEFTPADDING",   (0,0), (-1,-1), 6),
    ("ALIGN",         (1,0), (1,-1), "CENTER"),
])
nv_table_data = [["Parameter", "Normal Range"]] + nv_rows
nv_table = Table(nv_table_data, colWidths=[45*mm, 38*mm])
nv_table.setStyle(nv_style)

# Right: Henderson-Hasselbalch + pH rules
hh_content = [
    Paragraph("Henderson–Hasselbalch", S("hh_h", fontSize=9, fontName="Helvetica-Bold",
              textColor=TEAL)),
    Spacer(1,3),
    Paragraph("pH = 6.1 + log₁₀( [HCO₃⁻] / 0.03 × PaCO₂ )", FORMULA),
    Spacer(1,6),
    Paragraph("Buffers", S("buf_h", fontSize=9, fontName="Helvetica-Bold", textColor=TEAL)),
    Spacer(1,3),
    Paragraph("• Lungs control PaCO₂ (fast: minutes)", BODY),
    Paragraph("• Kidneys control HCO₃⁻ (slow: hours–days)", BODY),
    Paragraph("• Bicarbonate buffer: H⁺ + HCO₃⁻ ⇌ H₂CO₃ ⇌ H₂O + CO₂", BODY),
    Spacer(1,6),
    Paragraph("pH Rules", S("buf_h", fontSize=9, fontName="Helvetica-Bold", textColor=TEAL)),
    Spacer(1,3),
    Paragraph("pH < 7.35 → Acidemia", S("ar", fontSize=9, fontName="Helvetica-Bold", textColor=ACIDRED)),
    Paragraph("pH > 7.45 → Alkalemia", S("al", fontSize=9, fontName="Helvetica-Bold", textColor=ALKBLUE)),
    Paragraph("pH 7.35–7.45 → Normal (mixed disorder may still exist!)", BODY),
]

row1 = Table([[nv_table, hh_content]],
             colWidths=[87*mm, W - 87*mm - 4*mm],
             spaceBefore=0)
row1.setStyle(TableStyle([
    ("VALIGN",        (0,0), (-1,-1), "TOP"),
    ("LEFTPADDING",   (0,0), (-1,-1), 0),
    ("RIGHTPADDING",  (0,0), (-1,-1), 4),
    ("TOPPADDING",    (0,0), (-1,-1), 0),
    ("BOTTOMPADDING", (0,0), (-1,-1), 0),
]))
story.append(row1)
story.append(Spacer(1, 7))

# ── SECTION: Compensation Formulas ───────────────────────────────────────────
story.append(section_header("  COMPENSATION FORMULAS", NAVY))
story.append(Spacer(1, 4))

comp_rows = [
    # header
    [
        Paragraph("Disorder", S("ch", fontSize=9, fontName="Helvetica-Bold", textColor=WHITE, alignment=TA_CENTER)),
        Paragraph("Primary Change", S("ch", fontSize=9, fontName="Helvetica-Bold", textColor=WHITE, alignment=TA_CENTER)),
        Paragraph("Compensation", S("ch", fontSize=9, fontName="Helvetica-Bold", textColor=WHITE, alignment=TA_CENTER)),
        Paragraph("Formula", S("ch", fontSize=9, fontName="Helvetica-Bold", textColor=WHITE, alignment=TA_CENTER)),
        Paragraph("Onset", S("ch", fontSize=9, fontName="Helvetica-Bold", textColor=WHITE, alignment=TA_CENTER)),
    ],
    # Metabolic Acidosis
    [
        Paragraph("Metabolic\nAcidosis", S("d", fontSize=8.5, fontName="Helvetica-Bold", textColor=ACIDRED, leading=12)),
        Paragraph("↓ HCO₃⁻\n↓ pH", S("d", fontSize=8.5, fontName="Helvetica", textColor=NAVY, leading=12)),
        Paragraph("↓ PaCO₂\n(hyperventilation)", S("d", fontSize=8.5, fontName="Helvetica", textColor=NAVY, leading=12)),
        Paragraph("Winter's: PaCO₂ = 1.5×[HCO₃⁻] + 8 ± 2\nor ΔPaCO₂ = 1.1 × ΔHCO₃⁻",
                  S("f", fontSize=8.5, fontName="Helvetica-Bold", textColor=TEAL, leading=13)),
        Paragraph("12–24 h", S("d", fontSize=8.5, fontName="Helvetica", textColor=NAVY, leading=12)),
    ],
    # Metabolic Alkalosis
    [
        Paragraph("Metabolic\nAlkalosis", S("d", fontSize=8.5, fontName="Helvetica-Bold", textColor=ALKBLUE, leading=12)),
        Paragraph("↑ HCO₃⁻\n↑ pH", S("d", fontSize=8.5, fontName="Helvetica", textColor=NAVY, leading=12)),
        Paragraph("↑ PaCO₂\n(hypoventilation)", S("d", fontSize=8.5, fontName="Helvetica", textColor=NAVY, leading=12)),
        Paragraph("PaCO₂ = 0.7×[HCO₃⁻] + 20 ± 5\nor ΔPaCO₂ = 0.75 × ΔHCO₃⁻",
                  S("f", fontSize=8.5, fontName="Helvetica-Bold", textColor=TEAL, leading=13)),
        Paragraph("24–48 h", S("d", fontSize=8.5, fontName="Helvetica", textColor=NAVY, leading=12)),
    ],
    # Respiratory Acidosis Acute
    [
        Paragraph("Respiratory\nAcidosis\n(ACUTE)", S("d", fontSize=8.5, fontName="Helvetica-Bold", textColor=ACIDRED, leading=12)),
        Paragraph("↑ PaCO₂\n↓ pH", S("d", fontSize=8.5, fontName="Helvetica", textColor=NAVY, leading=12)),
        Paragraph("↑ HCO₃⁻\n(renal retention)", S("d", fontSize=8.5, fontName="Helvetica", textColor=NAVY, leading=12)),
        Paragraph("ΔHCO₃⁻ = +1 mEq/L per ↑10 mmHg PaCO₂\nΔpH = −0.08 per ↑10 mmHg PaCO₂",
                  S("f", fontSize=8.5, fontName="Helvetica-Bold", textColor=TEAL, leading=13)),
        Paragraph("Minutes\n(immediate)", S("d", fontSize=8.5, fontName="Helvetica", textColor=NAVY, leading=12)),
    ],
    # Respiratory Acidosis Chronic
    [
        Paragraph("Respiratory\nAcidosis\n(CHRONIC)", S("d", fontSize=8.5, fontName="Helvetica-Bold", textColor=colors.HexColor("#b71c1c"), leading=12)),
        Paragraph("↑ PaCO₂\n↓ pH", S("d", fontSize=8.5, fontName="Helvetica", textColor=NAVY, leading=12)),
        Paragraph("↑ HCO₃⁻\n(full renal)", S("d", fontSize=8.5, fontName="Helvetica", textColor=NAVY, leading=12)),
        Paragraph("ΔHCO₃⁻ = +4 mEq/L per ↑10 mmHg PaCO₂\nΔpH = −0.03 per ↑10 mmHg PaCO₂",
                  S("f", fontSize=8.5, fontName="Helvetica-Bold", textColor=TEAL, leading=13)),
        Paragraph("48–96 h", S("d", fontSize=8.5, fontName="Helvetica", textColor=NAVY, leading=12)),
    ],
    # Respiratory Alkalosis Acute
    [
        Paragraph("Respiratory\nAlkalosis\n(ACUTE)", S("d", fontSize=8.5, fontName="Helvetica-Bold", textColor=ALKBLUE, leading=12)),
        Paragraph("↓ PaCO₂\n↑ pH", S("d", fontSize=8.5, fontName="Helvetica", textColor=NAVY, leading=12)),
        Paragraph("↓ HCO₃⁻\n(renal loss)", S("d", fontSize=8.5, fontName="Helvetica", textColor=NAVY, leading=12)),
        Paragraph("ΔHCO₃⁻ = −2 mEq/L per ↓10 mmHg PaCO₂",
                  S("f", fontSize=8.5, fontName="Helvetica-Bold", textColor=TEAL, leading=13)),
        Paragraph("Minutes\n(immediate)", S("d", fontSize=8.5, fontName="Helvetica", textColor=NAVY, leading=12)),
    ],
    # Respiratory Alkalosis Chronic
    [
        Paragraph("Respiratory\nAlkalosis\n(CHRONIC)", S("d", fontSize=8.5, fontName="Helvetica-Bold", textColor=colors.HexColor("#0d47a1"), leading=12)),
        Paragraph("↓ PaCO₂\n↑ pH", S("d", fontSize=8.5, fontName="Helvetica", textColor=NAVY, leading=12)),
        Paragraph("↓ HCO₃⁻\n(full renal)", S("d", fontSize=8.5, fontName="Helvetica", textColor=NAVY, leading=12)),
        Paragraph("ΔHCO₃⁻ = −4 to −5 mEq/L per ↓10 mmHg PaCO₂",
                  S("f", fontSize=8.5, fontName="Helvetica-Bold", textColor=TEAL, leading=13)),
        Paragraph("48–96 h", S("d", fontSize=8.5, fontName="Helvetica", textColor=NAVY, leading=12)),
    ],
]

comp_table = Table(comp_rows,
                   colWidths=[30*mm, 25*mm, 32*mm, 68*mm, 22*mm])
comp_table.setStyle(TableStyle([
    ("BACKGROUND",    (0,0), (-1,0), NAVY),
    ("TEXTCOLOR",     (0,0), (-1,0), WHITE),
    ("ROWBACKGROUNDS",(0,1), (-1,-1), [GREY, WHITE, colors.HexColor("#fff0f0"),
                                       colors.HexColor("#ffe8e8"),
                                       colors.HexColor("#e8f0ff"), colors.HexColor("#ddeeff")]),
    ("GRID",          (0,0), (-1,-1), 0.4, MID_GREY),
    ("VALIGN",        (0,0), (-1,-1), "MIDDLE"),
    ("TOPPADDING",    (0,0), (-1,-1), 5),
    ("BOTTOMPADDING", (0,0), (-1,-1), 5),
    ("LEFTPADDING",   (0,0), (-1,-1), 5),
    ("RIGHTPADDING",  (0,0), (-1,-1), 4),
    ("ALIGN",         (0,0), (-1,0), "CENTER"),
]))
story.append(comp_table)
story.append(Spacer(1, 7))

# ── ROW 3: MUDPILES + Delta-Delta in two columns ──────────────────────────────
story.append(section_header("  METABOLIC ACIDOSIS CLASSIFICATION & TOOLS", NAVY))
story.append(Spacer(1, 4))

# Left: MUDPILES
mudpiles_letter_style = S("ml", fontSize=16, fontName="Helvetica-Bold",
                          textColor=GOLD, leading=20)
mudpiles_text_style   = S("mt", fontSize=8.5, fontName="Helvetica",
                          textColor=NAVY, leading=13)
mudpiles_bold_style   = S("mb", fontSize=8.5, fontName="Helvetica-Bold",
                          textColor=NAVY, leading=13)

mudpiles_items = [
    ("M", "Methanol"),
    ("U", "Uremia (renal failure)"),
    ("D", "DKA / Diabetic Ketoacidosis\n   (also: alcoholic, starvation)"),
    ("P", "Propylene glycol / Paraldehyde"),
    ("I", "Isoniazid / Iron"),
    ("L", "Lactic Acidosis (sepsis, ischemia,\n   metformin, mitochondrial)"),
    ("E", "Ethylene Glycol"),
    ("S", "Salicylates"),
]

mudpiles_rows = [[Paragraph(l, mudpiles_letter_style), Paragraph(t, mudpiles_text_style)]
                 for l, t in mudpiles_items]
mudpiles_header = [[
    Paragraph("MUDPILES — High Anion Gap Metabolic Acidosis",
              S("mh", fontSize=9, fontName="Helvetica-Bold", textColor=WHITE)),
    ""
]]
mudpiles_data = mudpiles_header + mudpiles_rows
mudpiles_table = Table(mudpiles_data, colWidths=[12*mm, 75*mm])
mudpiles_table.setStyle(TableStyle([
    ("SPAN",          (0,0), (1,0)),
    ("BACKGROUND",    (0,0), (-1,0), RED_BOX),
    ("TEXTCOLOR",     (0,0), (-1,0), WHITE),
    ("ROWBACKGROUNDS",(0,1), (-1,-1), [colors.HexColor("#fff8e1"), colors.HexColor("#fff3cd")] * 5),
    ("GRID",          (0,0), (-1,-1), 0.4, MID_GREY),
    ("VALIGN",        (0,0), (-1,-1), "MIDDLE"),
    ("TOPPADDING",    (0,0), (-1,-1), 4),
    ("BOTTOMPADDING", (0,0), (-1,-1), 4),
    ("LEFTPADDING",   (0,0), (-1,-1), 5),
    ("RIGHTPADDING",  (0,0), (-1,-1), 5),
    ("ALIGN",         (0,1), (0,-1), "CENTER"),
]))

# Right column: Anion Gap + Non-AG + Delta-Delta
right_content_items = []

# Anion Gap formula box
ag_box_data = [[
    Paragraph("Anion Gap Formula", S("agb_h", fontSize=9, fontName="Helvetica-Bold", textColor=WHITE)),
]],[
    Paragraph("AG = [Na⁺] − ([Cl⁻] + [HCO₃⁻])", FORMULA),
    Paragraph("Normal: 8–12 mEq/L  (up to 13 mEq/L)", BODY),
    Paragraph("⚠ Albumin Correction: Add 2.5 mEq/L per\n   1 g/dL albumin below 4 g/dL", BODY),
]]
ag_box = Table([
    [Paragraph("Anion Gap Formula", S("agb_h", fontSize=9, fontName="Helvetica-Bold", textColor=WHITE))],
    [Paragraph("AG = [Na⁺] − ([Cl⁻] + [HCO₃⁻])", FORMULA)],
    [Paragraph("Normal: 8–12 mEq/L  (up to 13 mEq/L)", BODY)],
    [Paragraph("⚠ Albumin correction: +2.5 per 1 g/dL below 4", BODY)],
], colWidths=[W - 87*mm - 6*mm])
ag_box.setStyle(TableStyle([
    ("BACKGROUND",    (0,0), (-1,0), GREEN),
    ("TEXTCOLOR",     (0,0), (-1,0), WHITE),
    ("BACKGROUND",    (0,1), (-1,-1), colors.HexColor("#e8f5e9")),
    ("GRID",          (0,0), (-1,-1), 0.4, MID_GREY),
    ("TOPPADDING",    (0,0), (-1,-1), 4),
    ("BOTTOMPADDING", (0,0), (-1,-1), 4),
    ("LEFTPADDING",   (0,0), (-1,-1), 6),
    ("RIGHTPADDING",  (0,0), (-1,-1), 6),
]))

# Non-AG causes
nonag_rows = [
    [Paragraph("NON-AG (Hyperchloremic) Acidosis",
               S("nah", fontSize=9, fontName="Helvetica-Bold", textColor=WHITE))],
    [Paragraph("D  Diarrhea (GI HCO₃⁻ loss)", BODY)],
    [Paragraph("R  Renal Tubular Acidosis (RTA I, II, IV)", BODY)],
    [Paragraph("U  Ureteral diversion", BODY)],
    [Paragraph("G  Go easy on saline (0.9% NaCl resuscitation)", BODY)],
    [Paragraph("S  acetazolamide (Carbonic anhydrase inhibitors)", BODY)],
]
nonag_table = Table(nonag_rows, colWidths=[W - 87*mm - 6*mm])
nonag_table.setStyle(TableStyle([
    ("BACKGROUND",    (0,0), (-1,0), colors.HexColor("#455a64")),
    ("TEXTCOLOR",     (0,0), (-1,0), WHITE),
    ("ROWBACKGROUNDS",(0,1), (-1,-1), [colors.HexColor("#eceff1"), WHITE] * 5),
    ("GRID",          (0,0), (-1,-1), 0.4, MID_GREY),
    ("TOPPADDING",    (0,0), (-1,-1), 4),
    ("BOTTOMPADDING", (0,0), (-1,-1), 4),
    ("LEFTPADDING",   (0,0), (-1,-1), 6),
    ("RIGHTPADDING",  (0,0), (-1,-1), 6),
]))

# Delta-Delta
dd_rows = [
    [Paragraph("Delta–Delta Ratio  (High-AG only)",
               S("ddh", fontSize=9, fontName="Helvetica-Bold", textColor=WHITE)), ""],
    [Paragraph("ΔAG / ΔHCO₃⁻  =  (AG−12) / (24−HCO₃⁻)",
               S("ddf", fontSize=9, fontName="Helvetica-Bold", textColor=TEAL)), ""],
    [Paragraph("< 1", S("d1", fontSize=9, fontName="Helvetica-Bold", textColor=ACIDRED)),
     Paragraph("Mixed: High-AG + Normal-AG acidosis", BODY)],
    [Paragraph("1 – 2", S("d2", fontSize=9, fontName="Helvetica-Bold", textColor=GREEN)),
     Paragraph("Pure High-AG metabolic acidosis", BODY)],
    [Paragraph("> 2", S("d3", fontSize=9, fontName="Helvetica-Bold", textColor=ALKBLUE)),
     Paragraph("Mixed: High-AG acidosis + Metabolic alkalosis", BODY)],
]
dd_table = Table(dd_rows, colWidths=[18*mm, W - 87*mm - 6*mm - 18*mm])
dd_table.setStyle(TableStyle([
    ("SPAN",          (0,0), (1,0)),
    ("SPAN",          (0,1), (1,1)),
    ("BACKGROUND",    (0,0), (-1,0), TEAL),
    ("TEXTCOLOR",     (0,0), (-1,0), WHITE),
    ("BACKGROUND",    (0,1), (-1,1), colors.HexColor("#e0f7f7")),
    ("ROWBACKGROUNDS",(0,2), (-1,-1), [colors.HexColor("#fce4ec"),
                                       colors.HexColor("#e8f5e9"),
                                       colors.HexColor("#e3f2fd")]),
    ("GRID",          (0,0), (-1,-1), 0.4, MID_GREY),
    ("VALIGN",        (0,0), (-1,-1), "MIDDLE"),
    ("ALIGN",         (0,2), (0,-1), "CENTER"),
    ("TOPPADDING",    (0,0), (-1,-1), 4),
    ("BOTTOMPADDING", (0,0), (-1,-1), 4),
    ("LEFTPADDING",   (0,0), (-1,-1), 6),
    ("RIGHTPADDING",  (0,0), (-1,-1), 6),
]))

right_stack = Table([
    [ag_box],
    [Spacer(1, 4)],
    [nonag_table],
    [Spacer(1, 4)],
    [dd_table],
], colWidths=[W - 87*mm - 4*mm])
right_stack.setStyle(TableStyle([
    ("LEFTPADDING",   (0,0), (-1,-1), 0),
    ("RIGHTPADDING",  (0,0), (-1,-1), 0),
    ("TOPPADDING",    (0,0), (-1,-1), 0),
    ("BOTTOMPADDING", (0,0), (-1,-1), 0),
]))

mud_row = Table([[mudpiles_table, right_stack]],
                colWidths=[90*mm, W - 90*mm - 2*mm])
mud_row.setStyle(TableStyle([
    ("VALIGN",        (0,0), (-1,-1), "TOP"),
    ("LEFTPADDING",   (0,0), (-1,-1), 0),
    ("RIGHTPADDING",  (0,0), (-1,-1), 3),
    ("TOPPADDING",    (0,0), (-1,-1), 0),
    ("BOTTOMPADDING", (0,0), (-1,-1), 0),
]))
story.append(mud_row)
story.append(Spacer(1, 7))

# ── SECTION: Step-by-step approach ────────────────────────────────────────────
story.append(section_header("  STEP-BY-STEP ABG INTERPRETATION", TEAL))
story.append(Spacer(1, 4))

steps = [
    ("1", "Is the patient acidemic or alkalemic?",
     "pH < 7.35 → Acidemia    |    pH > 7.45 → Alkalemia    |    Normal pH does NOT rule out a mixed disorder"),
    ("2", "Identify the PRIMARY disorder",
     "pH↓ + PaCO₂↑ → Resp. Acidosis   |   pH↑ + PaCO₂↓ → Resp. Alkalosis\n"
     "pH↓ + HCO₃⁻↓ → Met. Acidosis   |   pH↑ + HCO₃⁻↑ → Met. Alkalosis"),
    ("3", "Is compensation APPROPRIATE?",
     "Apply formulas above. If values fall outside expected range → Mixed disorder present"),
    ("4", "Calculate Anion Gap (if met. acidosis)",
     "AG = Na⁺ − (Cl⁻ + HCO₃⁻).  Correct for albumin.  If AG elevated → apply Delta–Delta ratio"),
    ("5", "Assess OXYGENATION",
     "P/F ratio = PaO₂/FiO₂  (Normal >400 | Mild ARDS 200–300 | Mod 100–200 | Severe <100)\n"
     "A-a gradient = PAO₂ − PaO₂ (PAO₂ = 150 − PaCO₂/0.8 on room air)  Normal <15 mmHg"),
]

step_rows = []
for num, title, detail in steps:
    step_rows.append([
        Paragraph(num, S("sn", fontSize=14, fontName="Helvetica-Bold",
                         textColor=WHITE, alignment=TA_CENTER)),
        Paragraph(title, S("st", fontSize=9, fontName="Helvetica-Bold", textColor=NAVY)),
        Paragraph(detail, S("sd", fontSize=8, fontName="Helvetica", textColor=NAVY, leading=12)),
    ])

steps_table = Table(step_rows, colWidths=[10*mm, 52*mm, W - 62*mm - 2*mm])
steps_table.setStyle(TableStyle([
    ("BACKGROUND",    (0,0), (0,-1), TEAL),
    ("ROWBACKGROUNDS",(1,0), (-1,-1), [GREY, WHITE] * 5),
    ("GRID",          (0,0), (-1,-1), 0.4, MID_GREY),
    ("VALIGN",        (0,0), (-1,-1), "MIDDLE"),
    ("ALIGN",         (0,0), (0,-1), "CENTER"),
    ("TOPPADDING",    (0,0), (-1,-1), 6),
    ("BOTTOMPADDING", (0,0), (-1,-1), 6),
    ("LEFTPADDING",   (0,0), (-1,-1), 6),
    ("RIGHTPADDING",  (0,0), (-1,-1), 6),
    ("LINEBELOW",     (0,0), (-1,-2), 0.5, MID_GREY),
]))
story.append(steps_table)
story.append(Spacer(1, 7))

# ── SECTION: Clinical consequences + worked example in 2 columns ─────────────
story.append(section_header("  PHYSIOLOGIC CONSEQUENCES  &  WORKED EXAMPLE", NAVY))
story.append(Spacer(1, 4))

# Left: consequences tables
acid_rows = [
    [Paragraph("SEVERE ACIDEMIA (pH < 7.2)", S("ah", fontSize=9, fontName="Helvetica-Bold", textColor=WHITE)),
     Paragraph("SEVERE ALKALEMIA (pH > 7.6)", S("alh", fontSize=9, fontName="Helvetica-Bold", textColor=WHITE))],
    [Paragraph("CV: ↓ contractility, ↑ PVR, arrhythmias\n   reduced catecholamine response",
               S("d", fontSize=8, fontName="Helvetica", textColor=NAVY, leading=12)),
     Paragraph("CV: arteriolar constriction, ↓ coronary flow\n   arrhythmias, left-shift O₂ curve",
               S("d", fontSize=8, fontName="Helvetica", textColor=NAVY, leading=12))],
    [Paragraph("Resp: hyperventilation, dyspnea\n   respiratory muscle fatigue",
               S("d", fontSize=8, fontName="Helvetica", textColor=NAVY, leading=12)),
     Paragraph("Resp: hypoventilation",
               S("d", fontSize=8, fontName="Helvetica", textColor=NAVY, leading=12))],
    [Paragraph("Metabolic: insulin resistance, ↓ ATP\n   HYPERKALEMIA, protein catabolism",
               S("d", fontSize=8, fontName="Helvetica-Bold", textColor=ACIDRED, leading=12)),
     Paragraph("Metabolic: HYPOKALEMIA\n   ↓ ionized Ca²⁺, Mg²⁺, phosphate",
               S("d", fontSize=8, fontName="Helvetica-Bold", textColor=ALKBLUE, leading=12))],
    [Paragraph("Cerebral: AMS, coma,\n   inhibited cellular metabolism",
               S("d", fontSize=8, fontName="Helvetica", textColor=NAVY, leading=12)),
     Paragraph("Cerebral: ↓ CBF, tetany, seizures\n   delirium, coma",
               S("d", fontSize=8, fontName="Helvetica", textColor=NAVY, leading=12))],
]
conseq_table = Table(acid_rows, colWidths=[(W*0.52)/2]*2)
conseq_table.setStyle(TableStyle([
    ("BACKGROUND",    (0,0), (0,0), ACIDRED),
    ("BACKGROUND",    (1,0), (1,0), ALKBLUE),
    ("TEXTCOLOR",     (0,0), (-1,0), WHITE),
    ("ROWBACKGROUNDS",(0,1), (-1,-1), [colors.HexColor("#fce4ec"), colors.HexColor("#fff"),
                                       colors.HexColor("#ffebee"), colors.HexColor("#fff")]),
    ("GRID",          (0,0), (-1,-1), 0.4, MID_GREY),
    ("VALIGN",        (0,0), (-1,-1), "MIDDLE"),
    ("TOPPADDING",    (0,0), (-1,-1), 4),
    ("BOTTOMPADDING", (0,0), (-1,-1), 4),
    ("LEFTPADDING",   (0,0), (-1,-1), 5),
    ("RIGHTPADDING",  (0,0), (-1,-1), 5),
]))

# Right: Worked example - Salicylate toxicity
example_content = [
    Paragraph("Worked Example: Salicylate Toxicity",
              S("ex_h", fontSize=9, fontName="Helvetica-Bold", textColor=WHITE)),
]
eg_box_data = [
    [Paragraph("Worked Example: Salicylate Toxicity",
               S("ex_h", fontSize=9, fontName="Helvetica-Bold", textColor=WHITE))],
    [Paragraph("ABG:  pH 7.47  /  PaCO₂ 25 mmHg  /  PaO₂ 180 mmHg",
               S("eg", fontSize=8.5, fontName="Helvetica-Bold", textColor=NAVY))],
    [Paragraph("Step 1: pH 7.47 → Alkalemia", BODY)],
    [Paragraph("Step 2: PaCO₂ low (25) + pH high → Respiratory alkalosis", BODY)],
    [Paragraph("Step 3: Expected pH = 7.40 + [(40−25)/10 × 0.08] = 7.52\n"
               "Measured 7.47 < predicted 7.52 → concurrent Metabolic acidosis",
               S("eg3", fontSize=8.5, fontName="Helvetica-Bold", textColor=RED_BOX, leading=13))],
    [Paragraph("✓ Diagnosis: Mixed Respiratory Alkalosis + Metabolic Acidosis",
               S("eg4", fontSize=9, fontName="Helvetica-Bold", textColor=GREEN))],
    [Spacer(1, 3)],
    [Paragraph("K⁺ – pH Relationship",
               S("kph_h", fontSize=9, fontName="Helvetica-Bold", textColor=TEAL))],
    [Paragraph("Each ↓0.10 pH unit → K⁺ rises ~0.6 mEq/L\n"
               "Metabolic acidosis → Hyperkalemia (exception: DKA, lactic acidosis)\n"
               "Metabolic alkalosis → Hypokalemia", BODY)],
]
eg_box = Table(eg_box_data, colWidths=[W - (W*0.52) - 4*mm])
eg_box.setStyle(TableStyle([
    ("BACKGROUND",    (0,0), (-1,0), GOLD),
    ("TEXTCOLOR",     (0,0), (-1,0), NAVY),
    ("BACKGROUND",    (0,1), (-1,-1), colors.HexColor("#fffde7")),
    ("GRID",          (0,0), (-1,-1), 0.4, MID_GREY),
    ("TOPPADDING",    (0,0), (-1,-1), 4),
    ("BOTTOMPADDING", (0,0), (-1,-1), 4),
    ("LEFTPADDING",   (0,0), (-1,-1), 6),
    ("RIGHTPADDING",  (0,0), (-1,-1), 6),
]))

conseq_row = Table([[conseq_table, eg_box]],
                   colWidths=[W*0.52, W - W*0.52 - 2*mm])
conseq_row.setStyle(TableStyle([
    ("VALIGN",        (0,0), (-1,-1), "TOP"),
    ("LEFTPADDING",   (0,0), (-1,-1), 0),
    ("RIGHTPADDING",  (0,0), (-1,-1), 3),
    ("TOPPADDING",    (0,0), (-1,-1), 0),
    ("BOTTOMPADDING", (0,0), (-1,-1), 0),
]))
story.append(conseq_row)
story.append(Spacer(1, 7))

# ── FOOTER ────────────────────────────────────────────────────────────────────
story.append(hr())
story.append(Paragraph(
    "Sources: Barash Clinical Anesthesia 9e · Brenner & Rector's The Kidney · Rosen's Emergency Medicine · "
    "Sanagustín & Osredkar, Med Int 2026 [PMID 41473681] · Habib et al., S Afr Fam Pract 2025 [PMID 40336441]",
    SMALL))
story.append(Spacer(1, 2))
story.append(Paragraph("Generated by Orris Medical AI · For educational use only · Always verify against current clinical guidelines",
                        FOOTER_STYLE))

# ── BUILD ──────────────────────────────────────────────────────────────────────
doc.build(story)
print(f"PDF written to {OUTPUT}")

Running Command

cd /home/daytona/workspace/abg-reference && python generate_abg_pdf.py 2>&1

Reading File

Editing File

~/abg-reference/generate_abg_pdf.py

Successfully replaced 1 instance(s) of the string in '/home/daytona/workspace/abg-reference/generate_abg_pdf.py'

Running Command

cd /home/daytona/workspace/abg-reference && python generate_abg_pdf.py 2>&1

PDF generated successfully. Here it is:

ABG Quick Reference

PDF Document · PDF

The single-page A4 PDF includes:

Normal Values - all 6 parameters with reference ranges

Henderson-Hasselbalch - the core equation + pH rules (acidemia/alkalemia thresholds)

Compensation Formulas table - all 6 disorders (metabolic acidosis/alkalosis, respiratory acidosis acute/chronic, respiratory alkalosis acute/chronic) with formulas, direction of compensation, and time to onset

MUDPILES mnemonic - colour-coded letter-by-letter with full cause names

Non-AG Acidosis causes - diarrhea, RTA, ureteral diversion, saline, acetazolamide

Anion Gap formula + albumin correction rule

Delta-Delta ratio - with the 3 interpretation ranges colour-coded (red/green/blue)

5-Step ABG interpretation algorithm

Physiologic consequences of severe acidemia vs alkalemia side-by-side

Worked example - the classic salicylate toxicity mixed disorder walk-through

K+ - pH relationship quick reference

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