Ability of the Masimo pulse CO-Oximeter to detect changes in hemoglobin

Abstract

The decision to administer blood products is complex and multifactorial. Accurate assessment of the concentration of hemoglobin [Hgb] is a key component of this evaluation. Recently a noninvasive method of continuously measuring hemoglobin (SpHb) has become available with multi-wavelength Pulse CO-Oximetry. The accuracy of this device is well documented, but the trending ability of this monitor has not been previously described. Twenty patients undergoing major thoracic and lumbar spine surgery were recruited. All patients received radial arterial lines. On the contralateral index finger, a R1 25 sensor (Rev E) was applied and connected to a Radical-7 Pulse CO-Oximeter (both Masimo Corp, Irvine, CA). Blood samples were drawn intermittently at the anesthesia provider's discretion and were analyzed by the operating room satellite laboratory CO-Oximeter. The value of Hgb and SpHb at that time point was compared. Trend analysis was performed by the four quadrant plot technique, testing directionality of change, and Critchley's polar plot method testing both directionality and magnitude of the change in values. Eighty-eight samples recorded at times of sufficient signal quality were available for analysis. Four quadrant plot analysis revealed 94% of data within the quadrants associated with the correct direction change, and 90% of data points lay within the analysis bounds proposed by Critchley. Pulse CO-Oximetry offers an acceptable trend monitor in patients undergoing major spine surgery. Future work should explore the ability of this device to detect large changes in hemoglobin, as well as its applicability in additional surgical and non-surgical patient populations.

Accuracy of noninvasive haemoglobin measurement by pulse oximetry depends on the type of infusion fluid

“…This recently reviewed technique 1 has been used in studies involving volunteers and surgery, with varying conclusions about accuracy and precision. [2][3][4][5][6][7][8][9][10][11] However, little is known about how SpHb reacts to specific procedures performed during surgery, such as intravenous infusion of crystalloid and colloid fluid. There is some evidence that SpHb changes more than Hb during volume loading with Ringer's acetate 7 but no evaluation of the accuracy of SpHb during administration of colloid fluid has been performed.…”

The Accuracy and Reliability of Non-Invasive Haemoglobin Measurements in the Emergency Room: a Small Prospective Observational Quality Control Study from a Swiss University Hospital ED

“…The accuracy and reliability of the portable Pronto-7 Pulse COOximeter was reported in numerous studies conducted in the operating room [10][11][12][13][14][15][16][17][18][19][20][21] and in the intensive care unit [4,5,[22][23][24][25] with predominantly satisfactory performance. In a study done in bleeding trauma patients the agreement was moderate [bias (LOA) of -0.6 (-3.0; +1.9)] g/dl [26], where the limit of agreement is defined as the mean difference + twice the standard deviation of the differences [27].…”

Continuous noninvasive hemoglobin monitoring

“…Unfortunately, only a few studies have evaluated these devices' trending ability (Table 2) [10,24,[31][32][33]. Four studies have shown …”

“…To this point, a four-quadrant plot analysis is inadequate as this analysis simply provides the directionality of the Hb changes. Colquhoun et al[31] assessed the tracking ability using a polar plot analysis and found a good agreement with the concordance rate of 90%, whereas Giraud et al[32] reported a poor agreement with angular bias and SD of À17.38 AE 19.28. It is worth mentioning that most of the studies evaluating the NIHb tracking ability simply compared Hb values between two time points and did not include any clinical interventions, such as volume expansion or transfusion.…”