Clearance of Indocyanine Green in Severe Pediatric Burns

Abstract

Background: Clearance of indocyanine green dye (ICGc) reflects sinusoidal perfusion and hepatocyte cell membrane function. Thus, ICGc is a reflection of the functional reserve of intact hepatocytes. The purpose of this study was to identify predictors of ICGc in severely burned children during the acute hospitalization and at the time of discharge from the intensive care unit (ICU). A secondary aim was to determine the relationship between liver size and patient ICGc.

Methods: Twenty-six children (0.8-17 years old) with 35% or greater total body surface area burned (%TBSA-B) were included. Assessment of ICGc (in milliliters per minute per meter squared) was done during the acute hospitalization (median: 6 days after admission, median: 14 days postburn) and at the time of discharge from the ICU (median: 19 days after admission, median: 27 days postburn). Age, TBSA-B, % third-degree burns, inhalation injury, preexisting chronic malnutrition, hematocrit, liver dysfunction, and time from burn injury were incorporated in multiple linear regressions as predictive variables of ICGc. Only variables with p < 0.05 were retained in the final models.

Results: Time from injury and age were the strongest predictors of ICGc during the acute admission but not at the time of discharge from the ICU. Time from injury was negatively associated with ICGc, whereas age was positively associated. At the time of discharge from the ICU, ICGc was increased in proportion to the %TBSA-B, whereas inhalation injury and preexisting chronic malnutrition were associated with lower ICGc. There was no correlation between change-to-predicted liver length and ICGc.

Conclusions: The intrinsic ability of the liver to extract ICG from plasma was lower in younger burned patients during the acute admission and in those with preexisting chronic malnutrition and inhalation injury at the time of discharge from the ICU.

Level of evidence: Prognostic/Epidemiologic, level III.

Figure 1.

Adjusted means and 95% confident intervals for ICGc by age during the acute phase of the burn injury (A) and at the time of discharge from the ICU (B). Means for (A) have been adjusted for hematocrit and time from burn injury.

Figure 2.

Adjusted means and 95% confident intervals for ICGc by %TBSA burned. Means have been adjusted for hematocrit, inhalation injury and pre-existing chronic malnutrition.

Figure 3.

Adjusted means and 95% confident intervals for ICGc in patients with pre-existing chronic malnutrition (A) or inhalation injury (B). Means have been adjusted between each other and hematocrit.

Figure 4.

Correlation between age and absolute liver length (A), liver length normalized to body surface area (B) during the acute admission. Relationship between change to predicted liver length and ICGc during the acute phase of the injury (C) and at the time of discharge from the ICU (D).