2.3.1. Study population and baseline characteristics
In total, one hundred adult patients with critical illness (medical n=56, surgical n=44) were studied. With reference to glucose, there was a collection of the finger stick plasma glucose concentrations on each patient. The frequency of these measurements was dependent upon the stability of the patient’s plasma glucose, clinical condition and nutrition intake in ICU.
Due to the number of observations only the first 50 patients were examined. In the first 50 patients over the first seven days of ICU stay, there was a total of 3,674 Point of Care (POC) capillary blood glucose measurements. In these patients, there was a median of 11 Point of Care (POC) capillary blood glucose measurements in a 24 hour period. On analysis of these 3,674 Point of Care (POC) capillary blood glucose measurements there were 5 (0.1%) were <2.2mmol/l, 242 (6.6 %) were between 2.2- 4.4 mmol/l, 1747 (47.6%) were between 4.4-6.9 mmol/l, 1,067 (29%) were between 6.9-9.0 mmol/l, and 613 (16.7%) were >9.0 mmol/l. The daily average of these individual POC capillary glucose
measurements were consequently correlated with the daily Lab-Glucose measurements. These were significantly associated with each other over days 1-7 (rs=0.802, P<0.001), (rs
= 0.564, P<0.001), (rs = 0.428, P<0.01), (rs = 0.606, P<0.001), (rs = 0.519, P<0.001), (rs =
0.441, P<0.01) respectively. Therefore, the daily Lab-Glucose measurements were subsequently correlated with other 24 hour measurements in all 100 patients.
The characteristics of the patients with critical illness on admission are shown in Table 2-1. The majority of patients were male (59%) and over the age of eighteen. The median ICU stay was 11.7 days; the median APACHE II score was greater than 22, and a predicted
74
hospital mortality rate of ≥ 40%. Sixty five patients survived and thirty five patients died in the ICU.
The admission clinicopathological characteristics of the patients with critical illness are shown in Table 2-1. The median of finger stick glucose measurements was similar to that of the Lab-Glucose measurements (6.4 mmol/l and 6.6 mmol/l respectively), which was above the normal values and close to the upper limit of the target glucose concentration in the insulin protocol that applied in the study period (Figure 2-1 p. 91). The median daily caloric intake was 30.8 Kcalories. The median CRP concentration was elevated at 134 mg/l, median white cell count was close to the upper normal level 11.7 x 109, and the median albumin concentration was low with median concentration of 16 g/l. The mean administration of insulin, norepinephrine, epinephrine, hydrocortisone and dobutamine were 0.8 U hour -1, 0.5 mg hour-1, 0.1 mg hour-1, 1.5 mg hour-1, 3.4 mg hour-1 respectively. The administration of insulin ranged from zero to 9.3 units per hour, norepinephrine from zero to 4.1 mg per hour, epinephrine from zero to 2.7 mg per hour, hydrocortisone from zero to 16 mg per hour and dobutamine from zero to 76.4 mg per hour.
The admission clinicopathological characteristics of surgical and medical patients with critical illness medical are shown in Table 2-2. Compared with medical patients, surgical patients more likely to be male (P <0.05) and had lower insulin administration on
admission day (P <0.05). This was also the case in the subsequent six days of ICU stay, which was the mean of insulin administration in medical patients at the second day 2.6 u/hour and in surgical patients 1.2 u/hour (P <0.01), on the third day 2.8 u/hour for medical patients and 1.3 u/hour for surgical patients (P <0.01), 2.8 u/hour versus 1.2 u/hour in the fourth day (P <0.001), 3.0 u/hour versus 1.3 u/hour on the fifth day (P <0.001), 2.7 u/hour versus 1.6 u/hour on the sixth day (P <0.01), and 2.6 versus 1.3 u/hour in the seventh day (P <0.01).
75
The relationship between plasma glucose and other variables and ICU death is shown in Tables 2-3. Compared with survivors, on the admission day non-survivors were older (P <0.01), had higher albumin concentration (P < 0.01). On multivariate logistic regression analysis of the significant variable identified (Table 2-4), only albumin (OR 0.895, 95%CI 0.825-0.971, P =0.007) was independently associated with death in ICU.
2.3.2. Relationship between plasma glucose and other variables
The inter-relationships between plasma glucose , CRP, white cell count, albumin, fluid balance, insulin, norepinephrine, epinephrine, dobutamine and hydrocortisone were examined and presented in series of supplemental Tables (2-5, 2-6 and 2-7) for the first, fourth and seventh days after admission to ICU.
On the first, forth and seven days after admission to ICU the inter-relationships between plasma glucose , CRP, white cell count, albumin, fluid balance, insulin, norepinephrine, epinephrine, dobutamine and hydrocortisone were examined and presented in series of supplemental Tables (2-5, 2-6 and 2-7).
Plasma glucose was directly associated with insulin on admission day (rs=0.321, P <0.01,
Table 2-5). It was also had a direct associated with epinephrine on admission day
(rs=0.307, P <0.01; Table 2-5), with albumin on the fourth day (rs =298, P <0.01; Table 2-
6), and with fluid balance on the seventh day (rs =285, P <0.01; Table 2-7). Caloric intake
was inversely associated with norepinephrine on admission (rs = -0.323, P =0.001; Table
2.5).
White cell count was directly associated with norepinephrine on admission day (rs =0.262,
P <0.01; Table 2-5). It was also associated with hydrocortisone on fourth day (rs= 0.316, P
<0.01; Table 2-6), and with fluid balance on the seventh day (rs= 0.283, P <0.01; Table 2-
76
0.538, P <0.001; Table 2-5) and fourth day (rs = -0.424, P <0.001; Table 2-6). It was also
inversely associated with norepinephrine on fourth (rs = -0.450, P <0.001; Table 2-6) and
seventh day (rs = - 290, P < 0.01; Table 2-7). Fluid balance was directly associated with
epinephrine on the fourth day (rs = 0.285, P <0.01; Table 2-6). It was also associated with
norepinephrine on fourth (rs = 0.595, P <0.001; Table 2-8), and with hydrocortisone on the
fourth (rs =258, P <0.01; Table 2-6) and seventh day (rs = 0.285, P <0.01; Table 2-7).
Insulin administration was directly associated with hydrocortisone on the seventh day (rs=
262, P < 0.01; Table 2-7). Norepinephrine was directly associated with dobutamine on admission day (rs=259, P <0.01; Table 2-5), fourth (rs= 0.304, P <0.01; Table 2-6) and
seventh day (rs= 0.277, P <0.01; Table 2-7), and with hydrocortisone on admission day
(rs= 0.499, P <0.001; Table 2-5), fourth (rs= 0.359, P <0.001; Table 2-6) and seventh day
(rs= 308, P <0.01; Table 2-7). Epinephrine was directly associated hydrocortisone on
admission day (rs=391, P <0.01; Table 2-5) and seventh day (rs= 0.272, P <0.01; Table 2-
7).
Of the 100 patients who were admitted in the ICU, they were had two further follow up samples during their ICU stay first was on forth day and last was on seventh day (Tables 2- 8 and 2-9 respectively). On the first follow up there was a significant increase in caloric intake (P <0.001), low albumin (P = 0.005), positive fluid balance (P =0.007) and high insulin administration (P < 0.001). On the last follow up there was a significant increase in caloric intake (P <0.001), low albumin (P = 0.011), high insulin administration (P < 0.001) and low norepinephrine and epinephrine administration (P <0.001, P = 0.003 respectively).
77