Confounding effects of blood hemoglobin and hematocrit levels on flap perfusion measurement with the Oxygen-to-see (O2C) analysis system in microvascular head and neck reconstruction– a retrospective study

Table 4 Multiple regression analysis

Variable	B (with CI)	p-value
Postoperative measurement - Hemoglobin concentration (AU) − 2-mm tissue depth
Hemoglobin (g/dL)	3.223 (0.151 - 6.294)	0.040
Ischemia duration (min)	-0.183 (-0.334 - -0.032)	0.019
Mean arterial blood pressure (mmHg)	-0.142 (-0.484 - 0.200)	0.411
Administered catecholamine dose (µg/min per kg)	28.529 (-17.628 - 74.686)	0.221
Postoperative measurement - Hemoglobin concentration (AU) − 2-mm tissue depth
Hematocrit (%)	1.095 (0.075 - 2.114)	0.036
Ischemia duration (min)	-0.184 (-0.335 - -0.033)	0.017
Mean arterial blood pressure (mmHg)	-0.133 (-0.475 - 0.208)	0.439
Administered catecholamine dose (µg/min per kg)	28.238 (-17.826 - 74.302)	0.225

Parameters are indicated as B regression coefficients (with 95% confidence interval) and p-values corresponding to multiple regression analysis for postoperative measurement of hemoglobin concentration (AU) in 2-mm tissue depth separately for hemoglobin concentration (g/dL) upon adjustment for ischemia duration (min), mean arterial blood pressure (mmHg), and administered catecholamine dose (µg/min per kg), and for hematocrit levels (%) upon adjustment for ischemia duration (min), mean arterial blood pressure (mmHg), and administered catecholamine dose (µg/min per kg) in patients reconstructed with a RFFF; abbreviations: CI = confidence interval; AU = arbitrary units

ISSN: 1471-2482