This lecture was conducted during the Nephrology Unit Grand Ground by a

Sub-intern under Nephrology Division, Department of Medicine in King Saud

University. Nephrology Division is NOT responsible for the content of the presentation for

it is intended for learning and /or education purpose only.

HOW TO APPROACH PATIENTS WITH ACIDOSIS

Hadeel Salah Al Jamei

• Definitions• Brief Physiology• Etiology• Presentation Of The Patient• How To Approach The Patient• Investigations

• Treatment

OUTLINE

• Acid, Acidosis, Acidemia?• pH?

• Base, Alkalosis, Alkalemia?• pH?

DEFINITIONS

• Buffer Systems (Buffer + H+ HBuffer)• Bicarbonate exatracellular

• CO2 + H2O H2CO3

• H2CO3 H+ + HCO3-

• Phospahte exatracellular

• Protiens intracellualr

• Respiratory Systems• Hypoventilation vs. hyperventilation

• Renal System

MEANS OF REGULATING H+

CAUSES OF ACIDOSIS

Causes Of Acidosis

Respiratory

Acute

Chronic

Metabolic

Normal Anion Gap

Increased Anion Gap

What is the anion gap?How to calculate it? [Na+] – [HCO3

-] – [Cl-]

SIGNS AND SYMPTOMS

Hx is V.IMP

Renal compensation

Respiratory compensation

respiratoryMetabolic

AlkalosisAcidosis

pH

Arterial blood sample

Metabolicrespiratory

Respiratory compensation

Renal compensation

pH < 7.35 pH > 7.45

HCO3- < 22

HCO3- < 22

HCO3- > 26 PCO2 > 45

PCO2 > 45 HCO3- > 26

PCO2 < 35

PCO2 < 35

OTHER MODALITIES OF INVESTIGATIONS

Metabolic

Anion gap

serum chemistry

Urinalysis

Ketone levels

Lactate levels

Salicylate levels

ECG

Respiratory

Chest X-ray

Ct scan

Drug toxicology

CT scan

MRI

PFTs

EMG

NCV

TREATMENT

Metabolic Acidosis

Treat the underlying cause

NaHCO3

Respiratory Acidosis

Treat the underlying cause

Pharmacological

Oxygen

Ventilatory support

ABC and Vitals

• History Is Important• Acidemia Or Alkalemia• Respiratory Or Metabolic• If respiratory: acute or chronic• If metabolic: normal or increased anion gap?

• Is There A Compensation?

SUMMARY

Acidosis App

Qx Calculate App

• Textbook of medical physiology by Guyton and Hall 11th edition

• Pocket medicine by marc sabatine 4th edition.• Step up to medicine 2nd edition.• http://emedicine.medscape.com/article/768268-

overview#a0104• http://emedicine.medscape.com/article/301574-overview• http://cmbi.bjmu.edu.cn/uptodate/critical%20care/

Intoxications/Approach%20to%20the%20patient%20with%20metabolic%20acidosis.htm

• http://fitsweb.uchc.edu/student/selectives/TimurGraham/Welcome.html

REFERENCES