Outcomes Associated With Transfusions in Critically Ill Children
Outcomes Associated With Transfusions in Critically Ill Children
Over the 1-year study period, there were 913 consecutive PICU admissions involving 802 patients (Fig. 1); 71 cases were excluded. A total of 842 admissions (cases) were retained for analysis. At least one RBC transfusion was given in 144 cases (17.1%).
(Enlarge Image)
Figure 1.
Flow chart of study patients. MODS = multiple organ dysfunction syndrome.
Data collected within 24 hours after PICU entry are reported in Table 1. Transfused cases were younger, more severely ill (higher PRISM and PELOD scores), and more likely to have congenital heart disease compared with nontransfused cases (34.7% vs 17.3%; p < 0.05). The hemoglobin concentration at admission was significantly lower in transfused cases (92 ± 29.6 g/L vs 115.7 ± 21.4 g/L; p < 0.05). The most frequent admission diagnoses were respiratory disease, bacterial or viral infection, and elective surgery (cardiac and noncardiac). Some admission diagnoses were significantly more prevalent in nontransfused cases (respiratory disease, viral infection, noncardiac surgery, and seizures), whereas others were significantly more prevalent in transfused cases (cardiac surgery and shock)
Data on transfusions are reported in Table 2. Five-hundred seventy-eight transfusions were given during the 1-year study period. The mean hemoglobin level before the first transfusion was 77.3 ± 27.2 g/L. Of the 144 first transfusion events, 110 (76.4%) were prescribed during the first 2 days in PICU.
Primary Outcome. NPMODS was observed in 99 of 842 patients (Table 3). The crude OR for development of NPMODS after the first transfusion event was 5.14 (95% CI, 3.28–8.06; p < 0.001). When controlling for potential confounders (admission PRISM score, age, and presence of a congenital heart disease), the association between RBC transfusion and NPMODS remained statistically significant (adjusted OR, 3.85; 95% CI, 2.38–6.24; p < 0.001)
Secondary Outcome. Nosocomial infections were increased in transfused cases (crude OR, 4.79; 95% CI, 2.54–9.03; p < 0.001), even after adjustment for the severity of illness at PICU entry (adjusted OR, 3.31; 95% CI, 1.67–6.56; p = 0.001). The association between RBC transfusion and 28-day mortality (crude OR, 9.49; 95% CI, 4.41–20.43; p < 0.001) was reduced but still statistically significant after controlling for severity of illness at PICU entry (adjusted OR, 5.12; 95% CI, 2.18–12.02; p < 0.001) (Table 3 and Table 4).
Mechanically ventilated transfused cases were intubated for longer periods of time than nontransfused cases (14.1 ± 32.6 d and 4.3 ± 9.6 d, respectively; p < 0.001). This association remained statistically significant after multivariable adjustment (hazard ratio [HR] of extubation [reflecting the rate of extubation for transfused cases vs nontransfused cases], 0.59; 95% CI, 0.45–0.79; p < 0.001) (Table 4). We observed an adjusted dose-effect relationship between RBC transfusion and length of mechanical ventilation (Fig. 2A).
(Enlarge Image)
Figure 2.
Adjusted survival curves showing the time from PICU admission to PICU discharge (A) and to extubation for ventilated children (B), stratified according to different levels of RBC transfusion. Adjustment was made for age and for admission Pediatric Risk of Mortality score. A, The corresponding hazard ratios are significantly higher for each of the two smallest categories (i.e., 0 and 1–20 cc/kg of RBCs during PICU stay) as compared with the reference group (> 80 cc/kg) (p < 0.05). In this analysis, a higher hazard ratio can be interpreted as a higher risk of PICU discharge and thus a shorter length of stay in PICU. B, The corresponding hazard ratios are significantly higher for each of the three smallest categories (i.e., 0, 1–20, and 21–40 cc/kg of RBCs during PICU stay) as compared with the reference group (> 80 cc/kg) (p < 0.05). In this analysis, a higher hazard ratio can be interpreted as a higher risk of extubation during PICU stay and thus a shorter duration of mechanical ventilation.
PICU length of stay was significantly increased in transfused cases (12.4 ± 26.2 d vs 4.9 ± 10.2 d; p < 0.001). The adjusted HR of PICU discharge for transfused cases versus nontransfused cases was 0.7 (95% CI, 0.57–0.85; p < 0.001) (Table 4). When considering different levels of exposure to RBCs, we observed an adjusted dose-effect relationship (Fig. 2B).
Tertiary Outcomes. The worst PaO2 was lower in transfused cases than in nontransfused cases (61.1 ± 26.5 and 83.5 ± 28.1 torr, respectively; p < 0.001), while it did not differ between the two groups at PICU admission (Table 1). This difference remained statistically significant even when children with and without a cyanotic heart disease were analyzed separately (Table 3). Furthermore, the worst PaO2 significantly decreased during the 6 hours following the first RBC transfusion (mean difference, 25.6 torr; p = 0.029) (Table 5). Pulse oximetry analysis also showed a small decrease between pretransfusion and posttransfusion worst oxygen saturation (SpO2), statistically but not clinically significant (95.9% ± 7.1% vs 95% ± 7%; p < 0.001) (Table 5).
The proportion of ARDS was similar in transfused and nontransfused cases (5.3% vs 4.2%; p = 0.54) (Table 3). Arterial hypotension was observed more frequently in transfused cases than in nontransfused cases (50.4% vs 28.3%; p < 0.001), but pre transfusion and posttransfusion prevalence of this complication did not differ (p = 1) (Table 5).
Renal replacement therapy was more frequent in transfused than in nontransfused cases (8.4% vs 0.6%; p < 0.001) (Table 3). It was also more prevalent after than before the first RBC transfusion (8.4% vs 2.3%; p = 0.008) (Table 5).
Finally, more transfused cases developed SIRS, sepsis, severe sepsis, or septic shock, but pretransfusion and posttransfusion prevalence of all these did not statistically differ (Table 5).
Results
Over the 1-year study period, there were 913 consecutive PICU admissions involving 802 patients (Fig. 1); 71 cases were excluded. A total of 842 admissions (cases) were retained for analysis. At least one RBC transfusion was given in 144 cases (17.1%).
(Enlarge Image)
Figure 1.
Flow chart of study patients. MODS = multiple organ dysfunction syndrome.
Data at First Day in PICU
Data collected within 24 hours after PICU entry are reported in Table 1. Transfused cases were younger, more severely ill (higher PRISM and PELOD scores), and more likely to have congenital heart disease compared with nontransfused cases (34.7% vs 17.3%; p < 0.05). The hemoglobin concentration at admission was significantly lower in transfused cases (92 ± 29.6 g/L vs 115.7 ± 21.4 g/L; p < 0.05). The most frequent admission diagnoses were respiratory disease, bacterial or viral infection, and elective surgery (cardiac and noncardiac). Some admission diagnoses were significantly more prevalent in nontransfused cases (respiratory disease, viral infection, noncardiac surgery, and seizures), whereas others were significantly more prevalent in transfused cases (cardiac surgery and shock)
Data on RBC Transfusions
Data on transfusions are reported in Table 2. Five-hundred seventy-eight transfusions were given during the 1-year study period. The mean hemoglobin level before the first transfusion was 77.3 ± 27.2 g/L. Of the 144 first transfusion events, 110 (76.4%) were prescribed during the first 2 days in PICU.
Outcomes and Their Association With RBC Transfusion
Primary Outcome. NPMODS was observed in 99 of 842 patients (Table 3). The crude OR for development of NPMODS after the first transfusion event was 5.14 (95% CI, 3.28–8.06; p < 0.001). When controlling for potential confounders (admission PRISM score, age, and presence of a congenital heart disease), the association between RBC transfusion and NPMODS remained statistically significant (adjusted OR, 3.85; 95% CI, 2.38–6.24; p < 0.001)
Secondary Outcome. Nosocomial infections were increased in transfused cases (crude OR, 4.79; 95% CI, 2.54–9.03; p < 0.001), even after adjustment for the severity of illness at PICU entry (adjusted OR, 3.31; 95% CI, 1.67–6.56; p = 0.001). The association between RBC transfusion and 28-day mortality (crude OR, 9.49; 95% CI, 4.41–20.43; p < 0.001) was reduced but still statistically significant after controlling for severity of illness at PICU entry (adjusted OR, 5.12; 95% CI, 2.18–12.02; p < 0.001) (Table 3 and Table 4).
Mechanically ventilated transfused cases were intubated for longer periods of time than nontransfused cases (14.1 ± 32.6 d and 4.3 ± 9.6 d, respectively; p < 0.001). This association remained statistically significant after multivariable adjustment (hazard ratio [HR] of extubation [reflecting the rate of extubation for transfused cases vs nontransfused cases], 0.59; 95% CI, 0.45–0.79; p < 0.001) (Table 4). We observed an adjusted dose-effect relationship between RBC transfusion and length of mechanical ventilation (Fig. 2A).
(Enlarge Image)
Figure 2.
Adjusted survival curves showing the time from PICU admission to PICU discharge (A) and to extubation for ventilated children (B), stratified according to different levels of RBC transfusion. Adjustment was made for age and for admission Pediatric Risk of Mortality score. A, The corresponding hazard ratios are significantly higher for each of the two smallest categories (i.e., 0 and 1–20 cc/kg of RBCs during PICU stay) as compared with the reference group (> 80 cc/kg) (p < 0.05). In this analysis, a higher hazard ratio can be interpreted as a higher risk of PICU discharge and thus a shorter length of stay in PICU. B, The corresponding hazard ratios are significantly higher for each of the three smallest categories (i.e., 0, 1–20, and 21–40 cc/kg of RBCs during PICU stay) as compared with the reference group (> 80 cc/kg) (p < 0.05). In this analysis, a higher hazard ratio can be interpreted as a higher risk of extubation during PICU stay and thus a shorter duration of mechanical ventilation.
PICU length of stay was significantly increased in transfused cases (12.4 ± 26.2 d vs 4.9 ± 10.2 d; p < 0.001). The adjusted HR of PICU discharge for transfused cases versus nontransfused cases was 0.7 (95% CI, 0.57–0.85; p < 0.001) (Table 4). When considering different levels of exposure to RBCs, we observed an adjusted dose-effect relationship (Fig. 2B).
Tertiary Outcomes. The worst PaO2 was lower in transfused cases than in nontransfused cases (61.1 ± 26.5 and 83.5 ± 28.1 torr, respectively; p < 0.001), while it did not differ between the two groups at PICU admission (Table 1). This difference remained statistically significant even when children with and without a cyanotic heart disease were analyzed separately (Table 3). Furthermore, the worst PaO2 significantly decreased during the 6 hours following the first RBC transfusion (mean difference, 25.6 torr; p = 0.029) (Table 5). Pulse oximetry analysis also showed a small decrease between pretransfusion and posttransfusion worst oxygen saturation (SpO2), statistically but not clinically significant (95.9% ± 7.1% vs 95% ± 7%; p < 0.001) (Table 5).
The proportion of ARDS was similar in transfused and nontransfused cases (5.3% vs 4.2%; p = 0.54) (Table 3). Arterial hypotension was observed more frequently in transfused cases than in nontransfused cases (50.4% vs 28.3%; p < 0.001), but pre transfusion and posttransfusion prevalence of this complication did not differ (p = 1) (Table 5).
Renal replacement therapy was more frequent in transfused than in nontransfused cases (8.4% vs 0.6%; p < 0.001) (Table 3). It was also more prevalent after than before the first RBC transfusion (8.4% vs 2.3%; p = 0.008) (Table 5).
Finally, more transfused cases developed SIRS, sepsis, severe sepsis, or septic shock, but pretransfusion and posttransfusion prevalence of all these did not statistically differ (Table 5).