Angiographic and histological evaluation of porcine retinal vascular damage and protection with perfluorocarbons after massive air embolism.

Abstract

BACKGROUND AND PURPOSE:

We have previously shown that perfluorocarbon emulsions (PFEs) reduce the severity of cerebral injury (indicated by infarct, reduced blood flow, and depressed EEG) induced by air embolism during cardiopulmonary bypass (CPB). This study used retinal fluorescein angiography to define the mechanisms of cerebral injury and to determine the efficacy of PFEs in cerebral protection. These angiographic findings were correlated to previously reported histologic findings.

METHODS:

Twenty domestic pigs underwent CPB with a prime of standard crystalloid or PFE (5 mg/kg) and crystalloid. After 10 minutes on CPB, a single (5 mL/kg) or double (2x2.5 mL/kg) bolus of room air or saline (control) was delivered via the right carotid artery. Retinal fluorescein angiograms were captured at 4 time points: baseline, air insult, postbypass, and postreperfusion. Following euthanasia, both eyes were removed and the retinas isolated for histological analysis with horseradish peroxidase (HRP), as previously reported.

RESULTS:

In control pigs, postreperfusion angiograms showed small nonperfused areas, and retinal whole mounts demonstrated vascular damage as previously reported. In 5 PFE-primed animals, postreperfusion angiograms showed hyperfluorescence, but angiograms and HRP mounts were otherwise not significantly different from baseline. Severely hyperfluorescent vessels observed angiographically also showed a correlation with HRP extravasation but were not consistently indicative of severe vascular damage.

CONCLUSIONS:

Retinal fluorescein angiography and retinal staining with HRP indicate that mechanisms of cerebral air embolism include nonperfusion, vascular leakage and spasm, red blood cell sludging, and hemorrhage. Priming with PFE prevented many of the sequelae associated with air embolism.

• Authors: J I Herren, K S Kunzelman, C Vocelka, R P Cochran, B D Spiess
• Journal: Stroke (Stroke) Vol. 29 Issue 11 Pg. 2396-403 (Nov 1998) ISSN: 0039-2499 [Print] United States
• PMID: 9804654 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, Non-P.H.S.)

Chemical References

• Fluorocarbons
• Neuroprotective Agents
• Horseradish Peroxidase

Topics

• Animals
• Capillaries
• Coronary Artery Bypass
• Embolism, Air (pathology, physiopathology)
• Endothelium, Vascular (drug effects)
• Fluorescein Angiography
• Fluorocarbons (pharmacology)
• Horseradish Peroxidase
• Neuroprotective Agents (pharmacology)
• Retina (drug effects, pathology)
• Retinal Artery
• Swine