The relationship between retinal perfusion and systemic haemodynamic function in sepsis.

Abstract

Purpose : Sepsis is a life-threatening disorder which results in end-organ microvascular dysfunction. There is currently no real-time method of monitoring microcirculatory perfusion during sepsis. OCTA allows visualisation and quantification of retinal blood flow. We performed a prospective observational study to investigate how retinal blood flow is altered during sepsis and how this reflects end-organ perfusion. We hypothesised that retinal blood flow is reduced during sepsis and that this reduction correlates with organ dysfunction.

Methods : We recruited patients undergoing major upper gastrointestinal surgery with planned post-operative care in the intensive therapy unit (ITU) and individuals already admitted to the ITU with sepsis. OCTA scans from 67 right eyes (50 males, 17 females) and 63 left eyes (49 males, 14 females) were included in the final analysis. Blood flow metrics analysed included mean vessel length density, skeletal density, perfusion density, and foveal avascular zone (FAZ) area and perimeter. Haemodynamic data collected from each patient at the time of inpatient imaging included sequential organ failure assessment (SOFA) score (based on FO₂/PO₂, platelets, bilirubin, mean arterial pressure (MAP), creatinine, Glasgow coma scale, and urine output), C-reactive protein, and lactate levels.

Results : Blood flow was higher in non-septic patients compared with septic patients, with p<0.001 for all measures: mean: 0.20±0.03; skeleton: 0.33±0.04; perfusion density: 103.1±13.80. FAZ area was smaller in non-septic patients (-0.16mm²±0.05, p=0.004) as was perimeter (-0.40mm±0.10, p<0.001).
MAP had a positive relationship with retinal perfusion: mean: 0.003±0.001 per mmHg increase in MAP, p=0.03; skeleton: 0.005±0.002, p=0.01; perfusion density: 1.38±0.61, p=0.02. MAP was negatively related with FAZ area (-0.006±0.003, p=0.01) and perimeter (-0.024±0.009, p=0.01).
SOFA score had a negative relationship with retinal perfusion (p<0.001 for all): mean: -0.013±0.003; skeleton: -0.026±0.003; perfusion density: -8.57±1.10. Scores were positively related to FAZ area (0.02±0.003, p<0.001) and perimeter (0.07±0.01, p<0.001).

Conclusions : There is a strong relationship between retinal blood flow measures and markers of haemodynamic function in septic patients, suggesting that retinal microvasculature could correlate with end-organ dysfunction in sepsis and may be used as a surrogate marker for end-organ perfusion.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.