Point-of-care assessment of microvascular blood flow in critically ill patients.
OBJECTIVE
Sublingual microvascular videomicroscopy can assess tissue perfusion in critically ill patients; however, data analysis is currently limited to delayed off-line evaluation. We hypothesized that a real-time point-of-care (POC) determination of the microcirculatory flow index (MFI), an established metric for assessing microcirculatory perfusion, agrees well with the conventional off-line analysis.


METHODS
Prospective observational study.


METHODS
Urban academic intensive care unit.


METHODS
A heterogeneous population of critically ill patients.


RESULTS
A single operator performed side stream darkfield videomicroscopy of the sublingual microcirculation and made a POC determination of MFI in real-time on a portable bedside monitor by assigning a score (0 = no flow to 3 = normal) to each quadrant of the image and averaging the four values. After image processing, de-identification and randomization, the same operator, blinded to the previous interpretation, repeated the MFI assessment by viewing an AVI-formatted image sequence on a 94 cm 1,080 pixel LCD monitor (reference standard). There were 205 paired measurements in 18 subjects. The POC and reference standard MFI had good agreement by Bland-Altman analysis [mean difference of -0.031, SD = 0.198 (95% CI, -0.43 to 0.37)]. The POC assessment was 94% sensitive and 92% specific for detecting impaired microvascular flow (defined a priori as an MFI < 2.5 based on previously published data).


CONCLUSIONS
A POC determination of MFI had good agreement with conventional off-line analysis, and was highly sensitive and specific for detecting impaired microvascular flow. This real-time technique may be useful in future clinical trials targeting impaired microcirculatory perfusion in critically ill patients.
Arnold
Ryan C
RC
Department of Emergency Medicine, UMDNJ-Robert Wood Johnson Medical School at Camden, Cooper University Hospital, One Cooper Plaza, Camden, NJ 08103, USA. arnold-ryan@cooperhealth.edu
Parrillo
Joseph E
JE
Phillip Dellinger
R
R
Chansky
Michael E
ME
Shapiro
Nathan I
NI
Lundy
David J
DJ
Trzeciak
Stephen
S
Hollenberg
Steven M
SM
D016638:Critical Illness; D006801:Humans; D008833:Microcirculation; D008875:Middle Aged; D009060:Mouth Floor / Q000098:blood supply*; D019095:Point-of-Care Systems; D011446:Prospective Studies; D012039:Regional Blood Flow