Visual outcomes after traumatic retrobulbar hemorrhage are not related to time or intraocular pressure.

BACKGROUND: The paucity of literature regarding the role of time and intraocular pressure (IOP) when treating ocular compartment syndrome (OCS) has resulted in limited guidance for emergency physicians (EP). OBJECTIVES: Our goals were to investigate the ideal time frame for lateral canthotomy, to understand the relationship between IOP and visual outcome, and to determine the impact of EP performance on visual acuity (VA). METHODS: The study population included patients presenting over an 18-year period with traumatic retrobulbar hemorrhage (RBH) treated with lateral canthotomy. Efficacy was evaluated using visual outcome and IOP. Patients were grouped by time from injury and arrival to canthotomy. Procedures completed in the emergency department (ED) and by EPs were evaluated regarding visual outcome. RESULTS: Sixty cases of RBH treated with lateral canthotomy were identified. Over two-thirds (43/60, 71.7%) were discharged with baseline vision. Lateral canthotomy lowered IOP from a median of 50.0 mmHg (IQR: 40.5, 61) preprocedure to 23.0 mmHg (IQR: 18, 27) post-procedure (p-value = 0.000001). No correlation was found between time, IOP, location, specialty of clinician, and visual outcome. CONCLUSION: Lateral canthotomy is an effective at lowering IOP. Our data suggest that using time and IOP to predict procedural outcome is flawed. If OCS is suspected, lateral canthotomy should be considered and can be effectively performed by EPs. Neither the time of injury to ED presentation nor degree of IOP elevation should be factored into the decision of when to perform the procedure.

Use of a portable forced air system to convert existing hospital space into a mass casualty isolation area.

STUDY OBJECTIVE: Patients with communicable diseases may require respiratory isolation to reduce the chance of transmission to health care workers and the public. This project was conducted to determine whether negative-pressure isolation for multiple patients can be achieved quickly and effectively using general hospital space not previously dedicated to respiratory isolation. METHODS: The physical therapy gymnasium was the area designated to test the ability to create a negative-pressure isolation environment in a large space. The conversion was planned in advance of an unscheduled drill to convert the space. Four high-efficiency particulate air (HEPA) filtered forced air machines were used to generate negative pressure. The units were vented to the outside air by a 25-foot length of 10-inch-diameter reusable duct. We evaluated the time needed for equipment setup and room conversion and noted any subjective difficulty with either setup or operation of the equipment. We measured the ability of the equipment to generate a negative air pressure relative to adjacent areas and determined the noise levels created during the use of different combinations of machines at various power settings. RESULTS: After drill activation and the request for equipment setup, 1 hour was required to convert the physical therapy gymnasium into an operational negative-pressure environment. The room pressure readings "high" power ranged from -1.5 to -13 Pa (-0.006 to -0.052 inches of water), and noise levels ranged from 70 to 76 dB. Calculated air changes per hour using 1, 2, 3, or 4 units running simultaneously at "high" power were 4.1, 8.2, 12.3, and 16.4, respectively. Using 4 units at once running at "low" power setting yielded 8.2 air changes per hour and generated a room pressure reading of -8.0 Pa, or -0.032 inches of water. CONCLUSION: Portable HEPA filtered forced air units are an effective means of creating large patient care areas with the negative-pressure environment required for respiratory isolation. This design results in a significantly lower-cost alternative compared with construction of individual rooms or units with similar capability and can be retrofitted to existing space. This type of unit would allow treatment of many more patients than current hospital capability would permit and would be an important asset in meeting the needs created by bioterrorism or a naturally occurring epidemic.