Positive end-expiratory pressure increases intraocular pressure in cats.

BACKGROUND AND METHODS: The purpose of the present study was to examine the effect of various levels of positive end-expiratory pressure on intraocular pressure in cats. Fourteen healthy adult cats (2.6 to 3.7 kg) without evidence of ocular disease were anesthetized with pentobarbital, paralyzed, and placed on mechanical ventilation. Direct continuous measurements of heart rate (HR), mean arterial pressure (MAP), CVP, CSF pressure, and intraocular pressure were recorded at zero end-expiratory pressure, and at 5, 10, and 15 cm H2O positive end-expiratory pressure, applied in random order. MAIN RESULTS: There were no significant changes in pHa, Paco2, HR, MAP, hematocrit, and temperature. Intraocular pressure increased significantly from 17 (during zero end-expiratory pressure) to 20 mm Hg at 10 cm H2O positive end-expiratory pressure; at 15 cm H2O positive end-expiratory pressure, intraocular pressure increased significantly to 21 mm Hg. CVP and CSF pressure increased significantly in parallel with intraocular pressure at 5, 10, and 15 cm H2O positive end-expiratory pressure. CONCLUSIONS: We speculate that similar responses occur in man, and may be undesirable in patients with already increased intraocular pressure, when higher levels of positive end-expiratory pressure are used.

An insertion technique for the double-closed-loop posterior chamber lens.

We have developed a technique for inserting double-closed-loop posterior chamber implants that minimizes zonular stress with both ciliary sulcus and capsular bag insertion and facilitates in-the-bag placement if desired.

An intraocular lens carrier.

An intraocular lens carrier for anterior and posterior chamber lenses has been developed. The device consists of a protective polypropylene envelope with an insertion leaf, which allows anterior chamber lenses to be inserted without iris or corneal touch and posterior chamber lenses to be guided into the ciliary sulcus or capsular bag with minimal or no haptic manipulation. +

The role of the submandibular glands in extrarenal erythropoietin production in mice.

The plasma erythropoietic activity of anephric mice and anephric mice without submandibular glands was compared. The erythropoietin production was stimulated by anemia (phenylhydrazine) and hypobaric hypoxia (0.4 atm). The activity was measured by the 59Fe incorporation in total circulating red blood cells in mice rendered polycythemic by hypoxia. The results were also calculated in units (IRP) of erythropoietin. The plasma erythropoietic activity of anephric mice was neutralized by antiserum against normal erythropoietin. Extrarenal erythropoietin production was significantly reduced in mice deprived of submandibular glands. These data indicate that this phenomenon is not restricted to the rat and support the concept that the submandibular glands are important extrarenal sources of erythropoietin.