Lab3064a.qxd

CASE STUDY #4
Performance of Masimo SET® Pulse Oximetry
in a Child with Meningococcemia
A 2 month old male with meningococcemia was admitted to the pediatric intensive care
unit (PICU) of a 242 bed regional medical center. Following admission, he developed respiratory failure, septic shock and DIC (disseminated intravascular coagulation), whichprogressed to renal failure. He required hemodialysis and significant inotropic support, includingdopamine, epinephrine and dobutamine. The patient received multiple infusions of fluid, FFP,PRBC's, and platelets and repeat doses of calcium, bicarbonate, Ampicillin, Claforan andSolumedrol.
As a result of deteriorating respiratory function, he was sedated, intubated with a 3.5 mmETT and mechanically ventilated with a Siemens Servo 300 in pressure control mode. Ventilatorsettings were optimized according to ABGs with FiO2 ranging from 0.5 to 1.0, PIP from 24 - 50,PEEP from 4 - 13, frequency from 30 - 40 and I: E ratios from 1:1.5 - 1:1. The patient remainedhemodynamically unstable and required continuous resuscitation efforts as described above.
Initial ABGs indicated a moderate metabolic acidosis (pH 7.31, PCO2 37, PO2 333, HCO3 18,base deficit -7, SaO2 98%) that continued to worsen to severe acidosis (pH 6.87, PCO2 84, PO229, HCO3 16, base deficit -18, SaO2 23%) despite maximum medical management efforts.
Upon arrival in the PICU, pulse oximetry monitoring of SpO2 was attempted without success.
Due to poor tissue perfusion and unstable hemodynamics, patient monitoring with oximetry,capnography, and transcutaneous O2 monitoring continued to be sporadic and not consistentwith ABG results. The initial pulse oximetry device used was a Siemens SC9000 oximetrymodule with a Nellcor disposable sensor. Monitoring from several different sites wasattempted with poor signal quality as evidenced by the plethysmographic waveform and onlyoccasionally valid SpO2 readings. Monitoring with a Nellcor N180 oximeter was then initiatedand monitoring at various sensor sites showed no improvement in monitoring performance.
Monitoring with a Novametrix 520A pulse oximeter and a Dura-Y sensor provided improvedplethysmographic waveforms but was unable to provide consistently accurate SpO2 readings.
Monitoring with the Masimo Radical pulse oximeter was then initiated with the pediatric finger sensor applied to the left index finger. Within the first minute, a plethysmographic waveformand SpO 2 data became available for the first time in several hours. Over the next five minutes the SpO2 data varied from 96% - 71%. ABGs were drawn (pH 7.14, PCO2 45, PO2 76, HCO3 15, base deficit -13, SaO2 93%) and the Masimo SET oximeter reading corresponded at 91%.
The ECG heart rate and the pulse rate displayed by the Radical oximeter correlated within 2-3 beats per minute. The Novametrix pulse oximeter continued to be used for comparativepurposes but was consistently unable to provide oximetry readings. The Masimo Radical pulse oximeter continued to read accurately consistent with ABGs and patient condition. When thearterial systolic pressures consistently fell below 90 mmHg and the pH remained <7.0 no pulseoximeter was able to provide oximetry readings. Eventually life support was terminated andthe patient expired 26 hours after admission.
DISCUSSION: Masimo SET pulse oximeter was able to provide clinically relevant and
apparently accurate oximetric data in the challenging situation of severe acidosis, varying
degrees of hypoxemia, and degrading hemodynamics when other devices were unable to perform.
During the final hours of the patient's life, no pulse oximeters were able to provide reliable
information.
The Masimo Radical pulse oximeter provided accurate monitoring of desaturation in a clinicalsituation where other brands of oximetry were only able to provide intermittent data readings,and were not able to reliably monitor during desaturation events. The accuracy of the oximetryreadings available from the Masimo Radical was superior to other oximetry devices when usedon a severely ill pediatric patient with extreme acidosis, hypoxemia, and low perfusion.
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Source: http://www.artemismedical.co.uk/pdf/masimo/Case4.pdf