What is the significance of an Arterial Oxygen Saturation (AS) of 0.15, or more specifically, severe hypoxemia?

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Last updated: April 30, 2025View editorial policy

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From the Guidelines

The use of ash with a value of 0.15 is not a medically recognized treatment and does not have a direct correlation with oxygen saturation levels or any specific medical condition. When considering oxygen therapy, the goal is to maintain an optimal oxygen saturation level, typically between 94-98% as suggested by the BTS guideline for oxygen use in adults in healthcare and emergency settings 1. This guideline emphasizes the importance of keeping the SaO2 above 90% for the majority of acutely ill patients to prevent hypoxic tissue injury. Key points to consider in oxygen therapy include:

  • The normal range for SaO2 in healthy adults at sea level is about 95-98% 1.
  • Sudden exposure to low SaO2 levels (below about 80%) can cause impaired mental functioning even in healthy participants 1.
  • Oxygen therapy is most effective in treating hypoxaemia caused by V/Q mismatch, such as in pneumonia, where hypoxic vasoconstriction may not be able to compensate for this mismatch 1. In the context of hypoxaemia, the management and treatment should focus on addressing the underlying cause, whether it be respiratory, cardiac, or another issue, rather than the use of ash or any non-medically recognized substances. For patients with specific conditions like decompensated cirrhosis, guidelines such as those from EASL provide recommendations for managing hypoxaemia, including the evaluation for liver transplantation in patients with hepatopulmonary syndrome (HPS) and severe hypoxaemia 1. However, these guidelines do not mention the use of ash in any context. Therefore, in clinical practice, the focus should be on evidence-based treatments that directly address the patient's medical condition and oxygen saturation levels, rather than unproven or non-medical interventions.

From the Research

Ash Content

  • The ash content of 0.15 is not directly related to the provided studies, which focus on the use of activated charcoal and N-acetylcysteine in the treatment of acetaminophen overdoses 2, 3, 4, 5, 6.
  • There is no mention of ash content in the provided studies, suggesting that it may not be a relevant factor in the treatment of acetaminophen overdoses with activated charcoal and N-acetylcysteine.

Activated Charcoal and N-Acetylcysteine

  • The use of activated charcoal and N-acetylcysteine in the treatment of acetaminophen overdoses is a topic of discussion in the provided studies 2, 3, 4, 5, 6.
  • Some studies suggest that activated charcoal may reduce the need for N-acetylcysteine treatment after acetaminophen overdose 4, while others recommend that N-acetylcysteine and activated charcoal not be used clinically until further studies are completed 2.
  • The adsorption of N-acetylcysteine by activated charcoal is also a topic of discussion, with some studies suggesting that it may reduce the effectiveness of N-acetylcysteine treatment 5, 6.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Concomitant use of activated charcoal and N-acetylcysteine.

Annals of emergency medicine, 1985

Research

N-acetylcysteine adsorption by activated charcoal.

Veterinary and human toxicology, 1980

Research

The effect of activated charcoal on N-acetylcysteine absorption in normal subjects.

The American journal of emergency medicine, 1987

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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