Risks Posed by Inaccurate Sensors
Inaccurate sensors pose a risk of inappropriate management of a patient. High reading sensors can lead to delayed interventions and insufficient oxygen therapy. Low reading sensors can lead to unnecessary interventions and lead to excessive oxygen therapy. Clinical trials have confirmed that inaccurate sensors can be identified and also concluded that if clinical decisions are based on data from inaccurate sensors patients can get the wrong management.
Many published clinical guidelines and
protocols recommend that decisions are based on very specific oxygen saturation
value cutoffs without the need for confirmation by blood gas (e.g. BTS
guidelines, National Institute for Health and Clinical Excellence http://www.nice.org.uk/guidance/CG/Published
, Scottish Intercollegiate Guidelines Network. Bronchiolitis in Children, NHS
Quality Improvement Scotland, The American Academy of Paediatrics - Diagnosis
and management of Bronchiolitis). Low reading sensors can lead
High reading sensors can lead to
- a falsely low estimation of the oxygen resulting in a decision to carry
out urgent immediate intubation with the related risks. This decision is only
shown to have been hasty retrospectively once there has been time to take
arterial blood and send it for detailed gas analysis.
- excess oxygen leading to Retinopathy of Prematurity (ROP) and blindness,
and chronic lung disease. The need for ‘low’ normal levels is recognised and
the exact limits of this are currently under investigation with the
multinational BOOST trials (Benefits Of Oxygen Saturation Targeting). (http://www.ctc.usyd.edu.au/BoostII/main_body/Home.htm).
In the UK alone some 2,500 premature babies have some scarring associated with
ROP and approximately 600 are blinded every year (based on National Statistics
Office and RNIB data).
- excess oxygen and metabolic disturbance in patients such as those with
reduced respiratory drive and/or at risk of hypercapnia (http://www.brit-thoracic.org.uk/LibraryGuidelines/tabid/69/Default.aspx
British Thoracic Society (BTS) Guidelines). This could be a patient with
chronic chest problems who usually runs with a relatively low normal oxygen
saturation where increasing their oxygen above the individuals norm leads to
carbon dioxide retention, metabolic acidosis and admission to Intensive Care.
- increased risk of carbon dioxide retention and hypercapnia in situations
such as overdose and poisoning.
- risks of increasing morbidity due to excess oxygen following hypoxic
insult, such as myocardial infarct or stroke. Recommendations are changing
from freely administering oxygen to titrating and prescribing the flow and
concentration of oxygen to achieve an appropriate accurately maintained oxygen
saturation to achieve correct tissue oxygenation. (BTS Guidelines).
- A falsely high estimation of oxygen saturation which can lead to a delay
in more active management. The decision to intubate an injured patient often
needs to be taken speedily and correctly whilst awaiting blood taking and
blood gas analysis.
- Hypoxic damage, including brain damage (cerebral palsy, strokes), organ
failure, etc due to poor tissue oxygenation.