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Low oxygen saturation: Really a hypoxia?

Raut MS, Maheshwari A - Saudi J Anaesth (2015 Apr-Jun)

View Article: PubMed Central - PubMed

Affiliation: Department of Cardiac Anesthesia, Dharam Vira Heart Center, Sir Ganga Ram Hospital, New Delhi, India.

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Before anesthesia induction, pulse oximetry probe was applied on left index finger and right radial artery was cannulated for blood pressure monitoring... During CPB, saturation was not displayed on pulse oximetry due to nonpulsatile perfusion flow... Saturation monitoring was done by in line arterial blood gas analysis, which was consistently above 95%... Another pulse oximetry probe was attached to ear lobule, which showed oxygen saturation (SpO2) of 99%... Pulse oximetry probe on the finger was examined, it was not misplaced, but dusky discoloration was observed on the left hand below forearm probably because of prolonged compression by leaning over by surgeon while operating... As the compressive effect was removed, SpO2 on the same finger probe showed saturation of 98% in a short period of time... Pulse oximeter system consists of a peripheral probe together with a microprocessor unit displaying a plethysmographic waveform, the SpO2 and the pulse rate... In the present case, patient's left forearm was compressed for a prolonged period due to leaning over by surgeon while operating... This led to venous congestion of hand and fingers... Arterial pulsation in hand may be attenuated, but still be present... Pulse oximetry probe placed on the finger detected more deoxygenated hemoglobin due to venous congestion in the finger and displayed low saturation [Figure 2]... However, arterial pulsation was still carried distally so giving good plethysmographic waveform... Before jumping on the diagnosis of hypoxia just on the basis of low SpO2 on pulse oximetry, first assess the proper plethysmographic waveform and then check SpO2 at other site also.

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Monitor display showing low saturation with good plethysmographic waveform
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Figure 1: Monitor display showing low saturation with good plethysmographic waveform

Mentions: A 50-year-old male patient with severe mitral stenosis was scheduled for mitral valve replacement. Before anesthesia induction, pulse oximetry probe was applied on left index finger and right radial artery was cannulated for blood pressure monitoring. Patient's saturation was 99% on pulse oximetry at room air. Surgery was done after going on cardiopulmonary bypass (CPB). During CPB, saturation was not displayed on pulse oximetry due to nonpulsatile perfusion flow. Saturation monitoring was done by in line arterial blood gas analysis, which was consistently above 95%. As the weaning from bypass was started, pulsatile arterial waveform appeared with pressure of 153/50 mmHg. However, pulse oximetry showed saturation of 65% with good plethysmographic waveform correlating with heart rate [Figure 1]. Another pulse oximetry probe was attached to ear lobule, which showed oxygen saturation (SpO2) of 99%. Arterial blood gas analysis revealed saturation of 98.9% with PaO2 of 178 mmHg on FiO2 of 0.5. Pulse oximetry probe on the finger was examined, it was not misplaced, but dusky discoloration was observed on the left hand below forearm probably because of prolonged compression by leaning over by surgeon while operating. As the compressive effect was removed, SpO2 on the same finger probe showed saturation of 98% in a short period of time.


Low oxygen saturation: Really a hypoxia?

Raut MS, Maheshwari A - Saudi J Anaesth (2015 Apr-Jun)

Monitor display showing low saturation with good plethysmographic waveform
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4374242&req=5

Figure 1: Monitor display showing low saturation with good plethysmographic waveform
Mentions: A 50-year-old male patient with severe mitral stenosis was scheduled for mitral valve replacement. Before anesthesia induction, pulse oximetry probe was applied on left index finger and right radial artery was cannulated for blood pressure monitoring. Patient's saturation was 99% on pulse oximetry at room air. Surgery was done after going on cardiopulmonary bypass (CPB). During CPB, saturation was not displayed on pulse oximetry due to nonpulsatile perfusion flow. Saturation monitoring was done by in line arterial blood gas analysis, which was consistently above 95%. As the weaning from bypass was started, pulsatile arterial waveform appeared with pressure of 153/50 mmHg. However, pulse oximetry showed saturation of 65% with good plethysmographic waveform correlating with heart rate [Figure 1]. Another pulse oximetry probe was attached to ear lobule, which showed oxygen saturation (SpO2) of 99%. Arterial blood gas analysis revealed saturation of 98.9% with PaO2 of 178 mmHg on FiO2 of 0.5. Pulse oximetry probe on the finger was examined, it was not misplaced, but dusky discoloration was observed on the left hand below forearm probably because of prolonged compression by leaning over by surgeon while operating. As the compressive effect was removed, SpO2 on the same finger probe showed saturation of 98% in a short period of time.

View Article: PubMed Central - PubMed

Affiliation: Department of Cardiac Anesthesia, Dharam Vira Heart Center, Sir Ganga Ram Hospital, New Delhi, India.

AUTOMATICALLY GENERATED EXCERPT
Please rate it.

Before anesthesia induction, pulse oximetry probe was applied on left index finger and right radial artery was cannulated for blood pressure monitoring... During CPB, saturation was not displayed on pulse oximetry due to nonpulsatile perfusion flow... Saturation monitoring was done by in line arterial blood gas analysis, which was consistently above 95%... Another pulse oximetry probe was attached to ear lobule, which showed oxygen saturation (SpO2) of 99%... Pulse oximetry probe on the finger was examined, it was not misplaced, but dusky discoloration was observed on the left hand below forearm probably because of prolonged compression by leaning over by surgeon while operating... As the compressive effect was removed, SpO2 on the same finger probe showed saturation of 98% in a short period of time... Pulse oximeter system consists of a peripheral probe together with a microprocessor unit displaying a plethysmographic waveform, the SpO2 and the pulse rate... In the present case, patient's left forearm was compressed for a prolonged period due to leaning over by surgeon while operating... This led to venous congestion of hand and fingers... Arterial pulsation in hand may be attenuated, but still be present... Pulse oximetry probe placed on the finger detected more deoxygenated hemoglobin due to venous congestion in the finger and displayed low saturation [Figure 2]... However, arterial pulsation was still carried distally so giving good plethysmographic waveform... Before jumping on the diagnosis of hypoxia just on the basis of low SpO2 on pulse oximetry, first assess the proper plethysmographic waveform and then check SpO2 at other site also.

No MeSH data available.