• 11
    Jun
  • Canadian HealthCare Mall: Results of Blood and Plasma Glucose

BloodAfter excluding 31 patients who did not authorize their medical records to be reviewed for research, 816 simultaneous bGlu and pGlu measurements were found for 197 patients. The mean age of these patients was 56 years (SD, 15.8 years), 95.4% were white, and 51.8% were women. The blood samples had been obtained on four occasions when patients were receiving continuous IV insulin treatment.

On 18 occasions, the bGlu level was reported as 400 mg/dL. In these cases, the mean pGlu level was 423 mg/dL (SD, 110 mg/dL; range, 300 to 900 mg/dL). On 767 occasions, the mean bGlu level was 159 mg/dL (SD, 56.4 mg/dL), and the mean pGlu level was 151 mg/dL (SD, 54.3 mg/dL; p < 0.001). The mean difference between measurements made using the two techniques was 7.9 mg/dL (SD, 17.6 mg/dL), and the limits of agreement were + 43.1 and -27.2 (Fig 1). The pGlu level was elevated on 589 occasions and was nonelevated on 178 occasions, when the pGlu level was between 50 and 400 mg/dL. The mean differences in pGlu and bGlu levels were not statistically significant between the elevated and nonelevated bGlu groups (p = 0.331). In the elevated pGlu group, the mean difference between measurements made using the two techniques was 7.6 mg/dL (SD, 17.1 mg/dL), and the limits of agreement were + 41.8 and -26.6, In the nonelevated pGlu group, the mean difference between measurements made using the two techniques was 9.0 mg/dL (SD, 19.1 mg/dL), and the limits of agreement were + 47.3 and -29.2.

MAP values were available on 741 occasions when pGlu was between 50 and 400 mg/dL, and the patients were hypotensive on 23 occasions (3.1%). The mean differences between pGlu and bGlu measurements were not statistically significant between the two MAP groups (p = 0.809). Without hypotension, the mean difference between the two techniques was 8.0 mg/dL (SD, 17.9 mg/dL), and the limits of agreement were + 43.7 and -27.7. When hypotension was present, the mean difference between measurements made using the two techniques was 8.9 mg/dL (SD, 14.4 mg/dL), and the limits of agreement were + 37.6 and -19.8. Information about vasopressor use was available on 740 occasions when the pGlu level was between 50 and 400 mg/dL. Patients were receiving vasopressor therapy on 180 occasions and were not receiving vasopressors on 560 occasions. The mean differences in pGlu and bGlu levels were not statistically significant between the occasions on which vasopressors had and had not been received (p = 0.399). When patients had received vasopressors, the mean difference between measurements using the two techniques was 9.0 mg/dL (SD, 10.6 mg/dL), and the limits of agreement were + 30.2 and -12.2. Without vasopressor use, the mean difference between measurements made using the two techniques was 7.8 mg/dL (SD, 19.5 mg/dL), and the limits of agreement were + 46.7 and -31.2. Follow the link diigo official website last news – Canadian Health&Care Mall, you may find the information which may have you forget about everything you have learnt already.

Vasopressor therapyDiscussion

Our results show that for the whole cohort, bGlu measurement provides, on average, a reasonable estimation of pGlu level, but for the individual patient bGlu measurement gives an unreliable estimate of pGlu level. The presence of hypotension and the use of vasopressors do not appear to affect the difference between pGlu and bGlu.

Our results are similar to those of four small studies, despite differences in the study designs and the glucose meter used. The relevance of these findings is not minor, particularly at lower glucose concentrations. For example, in our cohort, considering our limits of agreement, a patient with a bGlu level of 80 mg/dL might have a pGlu level of 51 mg/dL. Additionally, a fingerstick bGlu measurement has been shown to be inaccurate in patients who are in shock, low and high hematocrit values could overestimate or underestimate bGlu levels, and arterial whole-blood sampling overestimates bGlu level. In our study, the difference between bGlu and pGlu levels was not influenced by the presence of hypotension or the use of vasopressors. However, since < 5% of the blood samples were obtained when the patients were hypotensive, we cannot exclude an association between the patients’ hemodynamic status, and difference between bGlu and pGlu levels.

Our study has several limitations. The study was performed in a single tertiary medical center and had a retrospective design. Although we highlighted the discrepancies between bGlu and pGlu measurements, we did not have adequate data to address the safety and cost savings of the different bedside glucometry devices. The small number of patients with hypotension and the unavailability of hemoglobin concentrations also weakened our findings. Prospective studies may help to address some of these issues. In the meantime, every ICU should evaluate the discrepancy between bGlu and pGlu measurements, and the clinical implication of this discrepancy.

Fig1

Figure 1. Comparison of bGlu and pGlu measurements according to the method of Bland and Altman. The difference between measurements made using the two techniques was plotted against their mean.

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