Monitoring of the microcirculation in children undergoing major abdominal and thoracic surgery: A pilot study

Abstract

Background: Monitoring of the macrocirculation during surgery provides limited information on the quality of organ perfusion.

Objective: We investigated the feasibility of perioperative microcirculatory measurements in children.

Methods: Sublingual microvessels were visualized by handheld videomicroscopy in 11 children (19 mo - 10 yrs) undergoing surgery > 120 min at four time points: T0) after induction of anesthesia; T1) before end of anesthesia, T2) 6 h post surgery and T3) 24 h post surgery.

Results: Measurements were feasible in all children at T0 and T1. At T2 and T3, imaging was restricted to 6 and 4 infants, respectively, due to respiratory compromise and missing cooperation. The capillary density was reduced at T1 compared to T0 (8.1 mm/mm2 [4.0-17.0] vs. 10.6 mm/mm2 [5.1-19.3]; p = 0.01), and inversely related to norepinephrine dose (Pearson r = -0.65; p = 0.04). Microvascular flow and serum glycocalyx makers Syndecan-1 and Hyaluronan increased significantly from T0 to T1.

Conclusion: Perioperative microcirculatory monitoring in children requires a high amount of personal and logistic resources still limiting its routine use. Major surgery is associated with microvascular alterations and glycocalyx perturbation. The possible consequences on patient outcome need further evaluation. Efforts should concentrate on the development of next generation devices designed to facilitate microcirculatory monitoring in children.

Keywords: Microcirculation; blood flow; child; glycocalyx; microvascular density; surgery.

Fig. 1

Picture of the anesthesia induction room with the “microcirculation-imaging unit” including SDF-camera, computer, and monitor. To allow flexible recordings and changes between different locations (induction room, operating room, PICU), the equipment was placed on a mobile instrument card and provided with an uninterruptible power supply.

Fig. 2

Perioperative changes of microcirculatory parameters in sublingual vessels. Panels A-C include data of all children (n = 11), panels D-F include data from a subgroup of children (n = 6) with recordings available at timepoint T2. Small vessel density (A) decreased and the microvascular flow in small vessels (B) increased significantly from T0 to T1. The proportion of small vessels (<10 μm diameter) decreased significantly during surgery, while the proportion of medium vessels (10-25 μm diameter) increased significantly (C). Follow-up recordings 6 h post-surgery (T2) demonstrate a return of small vessel density (D), MFI (E), and diameter distribution (F) towards preoperative values.

Fig. 3

Perioperative evaluation of parameters of the endothelial glycocalyx. No significant change in the perfused boundary region (PBR) in sublingual vessels was observed from T0 to T1 (A) nor in the subgroup of children with recordings for timepoints T0 to T2 (B). Circulating serum levels of Syndecan-1 (C) and Hyaluronan (D) increased during surgery (values are corrected for total serum protein).