pH levels and Arterial Blood Gases

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pH levels and Arterial Blood Gases
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Blood pH

• Normal levels of pH are 0-14
• Below 6- acidic
• Above 7-alkaline
• Use pH paper to determine acidity or alkalinity
• These pH levels are used for chemicals, body
  fluids, such as urine, gastric content

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Acids

• Substances that when dissolved in water will
  ionize into positively charged hydrogen ions and
  negatively charged ions of some other element.

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Alkali (Bases)

• Substances that when dissolved in water ionizes
  into negatively charged hydroxide ions and
  positively charged ions of metal

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Neutralization

• This is the result when an acid and a base are
  combined to form a salt and a water.
• Example heartburn give antacids and neutralizes
  the acid into a salt and a water and the
  heartburn goes away.

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Arterial Blood

• Arterial Blood gas testing measures the dissolved
  O2 and CO2 and pH levels in the arterial blood.

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Arterial Blood gases

• The ABG measure the effectiveness of tissue
  perfusion and when imbalanced several health
  conditions can occur.

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pH

• The pH reflects the hydrogen ions in the
  circulating blood.
• This complex buffering system exists in the
  respiratory and cardiovascular mechanisms and
  keeps the systems in balance.

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Respiratory

• The lungs (respiratory) compensate for the
  imbalance within 2 to 3 hours.

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Metabolic

• The kidneys (metabolic) compensate for the
  imbalances within 2 to 3 days.

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Health problems that will alter ABG results

• Asthma
• Pneumonia
• Emphysema
• Hypoxia
• Sepsis (infection)
• Shock
• Anesthesia
• Drug overdose (Aspirin toxicity)

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Arterial Blood pH

• This is a useful indicator to determine acid/base
  balance within the body.
• Normal range is 7.35 to 7.45

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Homeostasis

• Intracellular- fluid within the cell
• Extracellular-fluid outside the cell

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Arterial blood gas (ABG)

• Arterial samples provide information about the
  ability of the lungs to regulate acid/base
  balance through retention or release CO2.
  Effectiveness of the kidneys maintaining
  appropriate bicarbonate levels can also be gauged.

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Application of ABG

• pH 7.35 to 7.45
• CO2- 35-45 (respiratory)
• HCO3- 24-28 (metabolic)
• O2 saturation- 80 to100

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Look at pH first

• pH
• Above 7.45- alkaline
• Below 7.35- acid

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respiratory

• CO2 above 45-acid
• Below 35 alkaline

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metabolic

• HCO3 above 28- alkaline
• Below 24 acid

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Example

• 24 year old female with drug overdose has
  following ABG results
• pH- 7.5
• CO2-40
• HCO3- 32
• pH elevated, alkaline, HCO3 elevated and alkaline
• Metabolic alkalosis