The acid base “balance”
This presentation is the property of its rightful owner.
Sponsored Links
1 / 25

Abelow, Understanding Acid-Base, Williams & Wilkins 1998 PowerPoint PPT Presentation


  • 51 Views
  • Uploaded on
  • Presentation posted in: General

The acid base “balance”. Abelow, Understanding Acid-Base, Williams & Wilkins 1998. (Abelow B, 1998 “Understanding Acid-Base”). (Abelow B, 1998 “Understanding Acid-Base”). Neuromuscular chain defects -may alter alveolar ventilation. (Abelow B, 1998 “Understanding Acid-Base”).

Download Presentation

Abelow, Understanding Acid-Base, Williams & Wilkins 1998

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Abelow understanding acid base williams wilkins 1998

The acid base “balance”

Abelow, Understanding Acid-Base, Williams & Wilkins 1998


Abelow understanding acid base williams wilkins 1998

(Abelow B, 1998 “Understanding Acid-Base”)


Abelow understanding acid base williams wilkins 1998

(Abelow B, 1998 “Understanding Acid-Base”)


Abelow understanding acid base williams wilkins 1998

Neuromuscular chain defects

-may alter alveolar ventilation

(Abelow B, 1998 “Understanding Acid-Base”)


Abelow understanding acid base williams wilkins 1998

Pulmonary diseases

-may alter alveolar ventilation

(Abelow B, 1998 “Understanding Acid-Base”)


Abelow understanding acid base williams wilkins 1998

HENDERSON-HASSELBALCH EQUATION

pH = pK + log [HCO3-]/0.03PCO2

pH = 6.1 + log 24/(0.03 x 40)

pH = 6.1 + log 24/1.2

pH = 6.1 + log 20

pH = 6.1 + 1.3

pH = 7.4

(Abelow B, 1998 “Understanding Acid-Base”)


Abelow understanding acid base williams wilkins 1998

Renal bicarbonate reabsorption

Abelow, Understanding Acid-Base, Williams & Wilkins 1998


Abelow understanding acid base williams wilkins 1998

Distal nephron luminal H+/K+ exchanger

(Abelow B, 1998 “Understanding Acid-Base”)


Abelow understanding acid base williams wilkins 1998

Abelow, Understanding Acid-Base, Williams & Wilkins 1998


Abelow understanding acid base williams wilkins 1998

RESPIRATORY ACIDOSIS

- Alveolar hypoventilation

: acute airway obstruction with underventilation

- Late acute asthma, acute COPD

: CNS - opiate overdose

- stroke

- neuropathy, myopathy


Abelow understanding acid base williams wilkins 1998

COMPENSATED RESPIRATORY ACIDOSIS

UNCOMPENSATED RESPIRATORY ACIDOSIS

Abelow, Understanding Acid-Base, Williams & Wilkins 1998


Abelow understanding acid base williams wilkins 1998

RESPIRATORY ALKALOSIS

- Alveolar hyperventilation

: Early acute asthma with over ventilation

: Pulmonary embolus, pneumonia, pulmonary oedema

: Anxiety


Abelow understanding acid base williams wilkins 1998

RESPIRATORY ALKALOSIS

Uncompensated

Compensated

Abelow, Understanding Acid-Base, Williams & Wilkins 1998


Abelow understanding acid base williams wilkins 1998

METABOLIC ACIDOSIS

- xs production of H+ ions

: Diabetic ketoacidosis

: Acute renal failure

: Circulatory shock (eg septic, cardiogenic,hypovolemic)


Abelow understanding acid base williams wilkins 1998

METABOLIC ACIDOSIS WITH RESPIRATORY COMPENSATION

UNCOMPENSATED METABOLIC ACIDOSIS

Abelow, Understanding Acid-Base, Williams & Wilkins 1998


Abelow understanding acid base williams wilkins 1998

METABLOIC ALKALOSIS

- xs HCO3- ions

: Loss of gastric fluid – vomiting

: Diuretics-K+ loss: xs renal HCO3reabsorption

:Post hypercapnic mechanical ventilation


Abelow understanding acid base williams wilkins 1998

METABOLIC ALKALOSIS

Abelow, Understanding Acid-Base, Williams & Wilkins 1998


Abelow understanding acid base williams wilkins 1998

When you see “respiratory”, think PCO2

and

When you see “metabolic”, think [HCO3-]

Abelow, Understanding Acid-Base, Williams & Wilkins 1998


Abelow understanding acid base williams wilkins 1998

Abelow, Understanding Acid-Base, Williams & Wilkins 1998


Abelow understanding acid base williams wilkins 1998

EVALUATION OF BLOOD GASES

Abelow, Understanding Acid-Base, Williams & Wilkins 1998


Abelow understanding acid base williams wilkins 1998

Abelow, Understanding Acid-Base, Williams & Wilkins 1998


Abelow understanding acid base williams wilkins 1998

RESPIRATORY FAILURE

Type 1:PaO2 PaCO2

- Alveolar hyperventilation

Type 2: PaO2 PaCO2

- Alveolar hypoventilation


Abelow understanding acid base williams wilkins 1998

ACUTE ASTHMA

Early:Alveolar hyperventilation -  respiratory drive PaO2 PaCO2

 give high concentration of O2 (60%)

Late:Alveolarhypoventilation- respiratorydrive

PaO2 PaCO2

: still relying on hypercapnic drive

 give high concentration of O2 (60%)

- may need mechanical ventilation


Abelow understanding acid base williams wilkins 1998

  • ACUTE EXACERBATION OF COAD

  • Chronic alveolar hypoventilation -  respiratory drive

  • - switch from hypercapnic to hypoxic drive

  • Use low concentration of O2 (24%) to avoid suppressing hypoxic drive

  • Can use central respiratory stimulation (doxapram) to permit higher concentration O2 (28-35%)


Abelow understanding acid base williams wilkins 1998

ARTERIAL BLOOD GASES IN ACUTE ASTHMA

Late Stage = Fatigue = Alveolar hypoventilation Early Stage = Alveolar hyperventilation

PaO2

1KPa = 7.5 mm Hg

PaCO2

  • If high PaCO2 (> 6KPa) and low PaO2 (< 8KPa) at presentation, or if rising PaCO2 and falling PaO2 despite treatment  mechanical ventilation (ie call anaesthetist)

  • Always use high flow O2 mask (> 60% inspired concentration) in acute asthma - even if high PaCO2 - as patient still relying on hypercapnic drive


  • Login