98th Annual Meeting DOG 2000

V 43

Irrigation after eye burns: solutions of different osmolarities and their effects on intracameral pH, corneal swelling and osmolarity

S. Kompa, H. Wüstemeyer, C. Neitzel, N. Schrage

Introduction: Rinsing solutions are mainly isotonic compared to the healthy cornea (0.4 Osmol/kg). Tap water is highly hypoosmolar
(0 Osmol/kg), whereas other solutions like Previnâ (Prevor) are hyperosmolar (0.8 Osmol/kg). The effects of irrigating solutions with varying osmolarities but without buffer capacities were evaluated.

Methods: 96 ex vivo porcine eyes and 8 in vivo rabbit eyes were treated. Tap water and saline solutions of different osmolarities (0.4, 0.8 and 1.2 Osmol/kg) were selected as rinsing solutions. Each eye was burnt with NaOH for 1 min followed by a 5 min irrigation with one of the solutions. Pachymetric measurements were performed on 72 porcine corneas immediately following alkali burn and during the irrigation. After the corneas were excised, their osmolarities were determined. A pH-electrode was placed intracamerally in 24 porcine eyes. The pH was continuously measured during and after irrigation until a constant value was measured. In order to examine the in vivo development of the intracameral pH of the burnt rabbit eye, the pH value was documented over a 3 h period after burning and irrigation with water or NaCl 0.9%, respectively.

Results: An antiproportional relationship between the osmolarity of the rinsing solution and corneal swelling could be observed (1). The osmolarity of the rinsing solution behaves proportional to the corneal osmolarity (2, ex vivo) and the intracameral pH-peak (3, in vivo).

 

0 Osmol/kg

0.4 Osmol/kg

0.8 Osmol/kg

1.2 Osmol/kg

1)Swelling

29.1% ± 7.0

18.0% ± 14.0

11.5% ± 3.9

7.6% ± 1.9

2)Osmol/kg

0.29 ± 0.04

0.41 ± 0.11

0.78 ± 0.21

0.91 ± 0.19

3)pH-Peak

Water O Osmol/kg: 10.2±0.2; NaCl 0.3Osmol/kg: 10.9±0.2

Discussion: Low osmolarities provide an enlarged diffusion barrier by corneal swelling and therefore a lower intracameral pH. A physiological tonicity inside the cornea is achieved by dilution of the agens. Solutions without buffer capacity should be hypoosmolar. Water is more effective than NaCl 0.9%.

University Eyeclinic, RWTH Aachen, Pauwelsstr. 30, D-52057 Aachen



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