Internal Medicine

P1: SBT

0521779407-02 CUNY1086/Karliner 0 521 77940 7 June 7, 2007 19:18

Acute Renal Failure Acute Respiratory Acidosis 55

■Hyperphosphatemia

➣Phosphate binders (Calcium Carbonate, Calcium Acetate)

➣Dietary phosphate restriction

Prognosis

■Length of stay doubled if ARF present.

■Most who survive ARF recover renal function.

■Mortality

➣7–23% non-ICU patients with ARF

➣50–80% ICU patients with ARF

➣Major causes of death: infections, cardiovascular disease

Acute Respiratory Acidosis..............................

F. JOHN GENNARI, MD

history & physical

■Acute respiratory distress

■Nausea and vomiting, headache

■Confusion, restlessness

■Coma, seizures

■Abnormal findings on chest exam

tests

Laboratory

■Arterial blood gases are diagnostic – PCO2 >45 mmHg, pH usually

<7.30 (see below for rule of thumb for [HCO3−])

Imaging

■Chest X-ray, CT of chest if necessary

differential diagnosis

■Conditions to distinguish from acute respiratory acidosis

➣Metabolic acidosis

➣Mixed disorders

➣Acute on chronic respiratory acidosis

➣Acute respiratory acidosis plus metabolic alkalosis

■Rule of Thumb:

➣Expected [HCO3−] in acute respiratory acidosis:

➣[HCO3−](expected)=24 mEq/L+0.1×(PCO2−40, mmHg)

Observed [HCO2−] should be within 4 mEq/L of the expected value

in uncomplicated acute respiratory acidosis, almost always−30 mEq/L