Table 1.
Summary of findings: microcirculatory studies performed in neonates.
| Reference | HVM | Study population | n | Area of interest | Findings |
|---|---|---|---|---|---|
| Genzel-Boroviczeny et al. (13) | OPS | Healthy preterm vs. term neonates | 28/9 | Cutaneous (upper inner arm) |
Application OPS imaging; groups did not differ; RBC velocity increased from day 1 to 5 in preterm neonates alongside decrease of Ht |
| Genzel-Boroviczeny et al. (41) | OPS | Anemic preterm neonates receiving blood transfusion | 13 | Cutaneous (upper inner arm) |
FVD increased after blood transfusion; other microcirculatory or macrocirculatory parameters were unaltered |
| Kroth et al. (42) | OPS | Healthy preterm neonates | 25 | Cutaneous (upper inner arm) |
FVD decreased from week 1 to 4 and was correlated with Hb and incubator temperatures; VD and RBC velocities did not change over time |
| Weidlich et al. (43) | OPS | Preterm neonates: proven infection vs. suspected but unproven infection |
17/9 | Cutaneous (upper inner arm) |
FVD varied widely, infection group showed 10% decline 5 days before AB compared to controls (intra-individual differences) |
| Top et al. (11) | OPS | Term neonates with severe respiratory failure: VA ECMO vs. controls |
14/10 | Buccal mucosa | FVD of ECMO patients was lower before start ECMO than of controls; FVD improved after ECMO |
| Hiedl et al. (44) | SDF | Preterm neonates: significant PDA vs. non-significant PDA | 13/12 | Cutaneous (upper inner arm) |
Group with significant PDA showed lower FVD and higher number of small vessels; after treatment groups did not differ |
| Top et al. (45) | OPS | Healthy term neonates vs. 1 to 6 month olds vs. 3 year olds | 22/19/4 | Buccal mucosa | FVD was highest in first week of life; after first week no correlation between FVD and age |
| Ergenekon et al. (46) | SDF | Neonates with polycythemia requiring partial exchange transfusion | 15 | Cutaneous (axilla) |
After transfusion MFI and number of vessels with hyperdynamic flow increased from baseline values |
| Top et al. (47) | OPS | Term neonates with severe respiratory failure: VA ECMO vs. controls | 21/7 | Buccal mucosa | FVD is preserved after start ECMO, while FVD deteriorated in ventilated controls |
| Alba-Alejandre et al. (48) | OPS | Term neonates: mild/moderate infection vs. controls |
16/31 | Cutaneous (ear conch) |
Infection group showed lower PPV with continuous flow than controls |
| Schwepcke et al. (49) | SDF | Preterm neonates: postnatal hypertension vs. controls | 10/11 | Cutaneous (upper inner arm) |
Preterm neonates with hypotension showed higher FVD in the first 6 h after birth; at 12 h after birth both blood pressure and FVD did not differ between groups |
| Tytgat et al. (12) | SDF | Neonates undergoing laparoscopic surgery for hypertrophic pyloric stenosis | 12 | Buccal and sublingual mucosa | Buccal FVD did not differ before and after surgery. Sublingual blood vessel diameters increased during CO2 insufflation and decreased after CO2 exsufflation |
| Ergenekon et al. (50) | SDF | Term neonates with HIE: TH vs. controls |
7/7 | Cutaneous (axilla) |
Patients showed lower MFI and more vessels with sluggish flow than controls. After TH parameters recovered to values of controls |
| Buijs et al. (6) | SDF | Term neonates with CDH: catecholamines vs. controls | 28/28 | Buccal mucosa | Catecholamines improved the macrocirculation, but did not alter the microcirculation; impaired microcirculation was predictive of outcome |
| Van den Berg et al. (35) |
SDF | Healthy term neonates | 28 | Cutaneous (upper inner arm)/buccal mucosa |
Application SDF imaging; reproducibility of buccal PVD with SDF imaging was confirmed, cutaneous PVD showed poor reproducibility |
| Van Elteren et al. (17) | SDF/IDF | Healthy preterm neonates | 20 | Cutaneous (upper inner arm) |
IDF imaging showed higher TVD and lower PPV values than SDF imaging because of higher image quality |
| Van Elteren et al. (51) | IDF | Healthy preterm vs. term neonates | 60/33 | Cutaneous (upper inner arm) |
TVD decreased in first month of life in both groups; TVD was higher in preterm than in term neonates |
| Gassmann et al. (52) | IDF | Healthy term neonates: born at high altitude vs. born at sea level |
53/33 | Cutaneous (upper inner arm) |
TVD was higher in neonates born at high altitude (lower SpO2 levels) than in neonates born at sea level |
| Wright et al. (36) | SDF | Healthy term neonates | 42 | Cutaneous (ear conch) |
Application SDF imaging; reporting of reference values for microcirculatory parameters for ear conch |
| Kulali et al. (53) | SDF | Healthy term neonates: vaginal delivery vs. cesarean section |
12/25 | Cutaneous (axilla) |
Vaginal delivery group showed more vessels with hyperdynamic flow than cesarean section group; other parameters did not differ between groups |
| Puchwein-Schwepcke et al. (54) | SDF | Term neonates: infection treated with antibiotics vs. controls | 13/95 | Cutaneous (ear conch) |
Infection group showed lower FVD and higher proportion of hyperdynamic flow than control group; hyperdynamic flow was associated with 5-fold increased risk for infection |
| Puchwein-Schwepcke et al. (55) | SDF | Preterm neonates with extreme LBW: hypercapnia vs. controls (sub-analysis RCT) | 6/6 | Cutaneous (upper inner arm) |
Hypercapnia group showed lower FVD and relatively fewer small vessels than controls |
BP, blood pressure; CDH, congenital diaphragmatic hernia; ECMO, extracorporeal membrane oxygenation; etCO2, end tidal carbon dioxide; FVD, functional vascular density; GA, gestational age; Hb, hemoglobin; HIE, hypoxic ischemic encephalopathy; HR, heart rate; Ht, hematocrit; HVM, handheld vital microscopy; IDF, incident dark field illumination; LBW, low birth weight; OPS, orthogonal polarization spectral; PDA, persistent ductus arteriosus; PPV, perfused vessel density (%); RBC, red blood cell; SDF, sidestream dark field; TH, therapeutic hypothermia; TVD, total vessel density; VA ECMO, veno-arterial extracorporeal membrane oxygenation; VD, vessel diameter.