Haemoglobin behaviour in critical patients

Purpose

A haemoglobin decrease is common in critical patients. We investigated the haemoglobin behaviour in nonbleeding patients during the first week of stay in the intensive care unit (ICU).

Methods

The study was retrospective and included 23 patients (16 men and seven women) in a seven-bed ICU from January to March 2001. Data were collected on days 1, 2, 4 and 7. We analysed the haemoglobin range and the possible causes related to it. We used the median and interquartile range to show the data.

Results

Patients ages were 63 years (41.76 years), the Acute Physiology and Chronic Health Evaluation (APACHE) II score was 22 (16.32), and the body mass index was 24 kg/m² (23.28 kg/m²). Haemoglobin medians were: day 1, 12 g/dl (10, 13 g/dl); day 2, 11 g/dl (9, 13 g/dl); day 4, 11 g/dl (9, 13 g/dl); day 7, 10 g/dl (8, 13 g/dl) (Friedman P < 0.001, post-hoc P < 0.05, day 1 > day 2, day 4, day 7). Fluid balance between day 1 and day 2 was 586 ml (-263, 2129 ml). The most important haemoglobin reduction occurred between day 1 and day 2. Factors analysed were: age (P = 0.369; R = 0.2), APACHE score (P = 0.05; R = -0.406), body mass index (P = 0.900; R = -0.005), gender (P = 0.007; R = -0.543; women were the majority), and fluid balance (P = 0.653; R = 0.105). The mortality rate was 30.4% and was not related to haemoglobin fall (P = 0.721; relative risk = 1.012, 95% confidence interval = 0.946–1.084). There was a nonsignificant fall in white blood cells and platelets between day 1 and day 2.

Conclusions

In our sample, we verified a major fall in haemoglobin between the first and second day of stay in the ICU. Female gender and, with least importance, the APACHE score were linked to a major fall in haemoglobin during the time of study.