Hemodynamic Response to Fluid Boluses for Hypotension in Children in a Cardiac ICU

Abstract

To describe the hemodynamic response to fluid boluses for hypotension in children in a cardiac ICU. DESIGN: A prospective, observational study. SETTING: Single-centered cardiac ICU. PATIENTS: Children in a cardiac ICU with hypotension. INTERVENTIONS: Clinician prescribed fluid bolus. MEASUREMENTS AND MAIN RESULTS: Sixty-four fluid boluses were administered to 52 children. Fluid composition was 4% albumin in 36/64 (56%), 0.9% saline in 18/64 (28%), and cardiopulmonary bypass pump blood in 10/64 (16%). The median volume and duration were 5.0 mL/kg (interquartile range, 4.8-5.4) and 8 minutes (interquartile range, 4-19), respectively. Hypovolemia/low filling pressures was the most common additional indication (25/102 [25%]). Mean arterial pressure response, defined as a 10% increase from baseline, occurred in 42/64 (66%) of all fluid boluses at a median time of 6 minutes (interquartile range, 4-11). Mean arterial pressure responders had a median peak increase in the mean arterial pressure of 15 mm Hg (43 mm Hg [interquartile range, 29-50 mm Hg] to 58 mm Hg [interquartile range, 49-65 mm Hg]) at 17 minutes (interquartile range, 14-24 min) compared with 4 mm Hg (48 mm Hg [interquartile range, 40-51 mm Hg] to 52 mm Hg [interquartile range, 45-56 mm Hg]) at 10 minutes (interquartile range, 3-18 min) in nonresponders. Dissipation of mean arterial pressure response, when defined as a subsequent decrement in mean arterial pressure below 10%, 5%, and 2% increases from baseline, occurred in 28/42 (67%), 18/42 (43%), and 13/42 (31%) of mean arterial pressure responders, respectively. Cardiopulmonary bypass pump blood was strongly associated with peak change in mean arterial pressure from baseline (coefficient 11.0 [95% CI, 4.3-17.7]; p = 0.02). Fifty out of 64 (78%) were receiving a vasoactive agent. However, change in vasoactive inotrope score was not associated with change in mean arterial pressure (coefficient 2.3 [95% CI,-2.5 to-7.2]; p = 0.35). Timing from admission, nor fluid bolus duration, influenced mean arterial pressure response. CONCLUSIONS: In children with hypotension in a cardiac ICU, the median dose and duration of fluid boluses were 5 mL/kg and 8 minutes. Peak response occurred shortly following administration and commonly returned to baseline.

Characteristics and Physiologic Changes After 4% Albumin Fluid Boluses in a PICU

“…Hourly interval measurements lack granularity for measured variables. However, it provides information regarding the sustained nature of any responses beyond the 30 minutes assessed in previous studies (2).…”

“…However, data from the EMR used signed nursing administration entries and only included FB duration in line with preferred ranges among clinicians in Australian and New Zealand PICU (7). The indications for FBT could not be determined from these data; however, from a recent prospective study, hypotension is most common (2). We limited the period of analysis to 4 hours following the FB, and therefore, any delayed effects on urine output, hematocrit, or serum lactate may have been missed.…”

“…For FBT, albumin is the preferred colloid of intensive care clinicians (1,7). Yet, little is known about In a recent study, of the minute-by-minute hemodynamic changes after 64 FBs in children with hypotension in a cardiac ICU, 4% albumin was administered in over half (2). A MAP response of greater than or equal to 10% from baseline occurred in two thirds.…”

“…Fluid bolus therapy (FBT) remains a frontline treatment for the resuscitation of children in intensive care. Crystalloids, including 0.9% saline and balanced solutions, are the preferred composition; however, 4% albumin may also be common (1), particularly following cardiac surgery (2). Albumin has the theoretical advantage of exerting an oncotic pressure effect, thus allegedly favoring fluid retention in the circulation and delivering a more pronounced hemodynamic effect compared with crystalloids.…”

Editor’s Choice Articles for August

“…This month, of particular note, Ranjit and colleagues (7) describe variability in hemodynamic response to a fluid bolus (10 mL/kg over 30 minutes) in 42 pediatric patients with septic shock. There are many articles about sepsis and septic shock in PCCM , but the two connection items to also consider are an article published in January 2021 on fluid responsiveness in hypotensive children in the CICU (8), and an article published in April 2021 on fluid responsiveness in hemodynamically unstable, ventilated neonates (9).…”