Mark Wefers Bettink

Chapter 4 74 did not differ significantly ( p =0.5) from the sampled PaO 2 of 101.0 mmHg [98.0 – 106.0]. When pressure was applied to the skin sensor the mitoPO 2 did not decrease, indicating the absence of mitochondrial respiration, as shown in Figure 5c. Within all subjects the mitochondrial respiration returned after approximately 15 minutes. No major adverse events caused by the cyanide application were witnessed. Apart from a temporarily red skin, no pain, skin irritation or other effects of the cyanide cream were reported. 3.2 Comparison of monitors Arterial occlusion of the arm led to an immediate decline and subsequent stop of microcirculatory blood flow measured by the O2C. MitoPO 2 and tissue oxygen saturation followed. A linear regression of the measured decline during the arterial occlusion with the cuff provided different slopes for all measurements as shown in Table 2. An example of measurements is shown in Figure 7A, with the mean of the z score of all subjects shown in Figure 7B. Table 2: Linear fit of arterial occlusion of the arm with a pressurized cuff Baseline value Median [IQR] Decline Mean ± SD z-score* Decline Mean MitoPO 2 (mmHg) 68 [61-76.5] -0,75 ± 0,06 -0,089 Flow O2C (FU) 35 [20-57] -2,30 ± 0,37 -0,15 sat O2C (%) 49 [43-65] -0,51 ± 0,05 -0,062 NIRS (%) 76 [72-82] -0,21 ± 0,04 -0,058 TcPCO 2 OxiVenT (mmHg) 51 [47-56] -0,37*10 -3 ± 0,03 -0,010 Heating OxiVenT (mWatt) 130 [123-142] -0,95*10 -1 ± 0,06 -0,050 *z-score = (data point-average)/standard deviation Interestingly the tcPCO 2 measurement was stable during this short arterial stop, although the heating power required to maintain a stable sensor temperature of 43 °C changed slightly. After a relatively long delay an increase in tcPCO 2 was seen.