[West J Emerg Med. 2011;12(1):139-140.]

Introduction: Point-of-care ocular ultrasound (US) is a valuable tool for the evaluation of traumaticocular injuries. Conventionally, any maneuver that may increase intraocular pressure (IOP) isrelatively contraindicated in the setting of globe rupture. Some authors have cautioned against theuse of US in these scenarios because of a theoretical concern that an US examination may causeor exacerbate the extrusion of intraocular contents. This study set out to investigate whether ocularUS affects IOP. The secondary objective was to validate the intraocular pressure measurementsobtained with the Diaton® as compared with standard applanation techniques (the Tono-Pen®).

Methods: We enrolled a convenience sample of healthy adult volunteers. We obtained thebaseline IOP for each patient by using a transpalpebral tonometer. Ocular US was then performedon each subject using a high-frequency linear array transducer, and a second IOP was obtainedduring the US examination. A third IOP measurement was obtained following the completionof the US examination. To validate transpalpebral measurement, a subset of subjects alsounderwent traditional transcorneal applanation tonometry prior to the US examination as a baselinemeasurement. In a subset of 10 patients, we obtained baseline pre-ultrasound IOP measurementswith the Diaton® and Tono-Pen®, and then compared them.

Results: The study included 40 subjects. IOP values during ocular US examination were slightlygreater than baseline (average +1.8mmHg, p=0.01). Post-US examination IOP values were notsignificantly different than baseline (average -0.15mmHg, p=0.42). In a subset of 10 subjects, IOPvalues were not significantly different between transpalpebral and transcorneal tonometry (average+0.03mmHg, p=0.07).

Conclusion: In healthy volunteer subjects, point-of-care ocular US causes a small and transientincrease in IOP. We also showed no difference between the Diaton® and Tono-Pen® methodsof IOP measurement. Overall, the resulting change in IOP with US transducer placement isconsiderably less than the mean diurnal variation in healthy subjects, or pressure generated byphysical examination, and is therefore unlikely to be clinically significant. However, it is important totake caution when performing ocular ultrasound, since it is unclear what the change in IOP would bein patients with ocular trauma. [West J Emerg Med. 2015;16(2):263–268.]

Introduction: In the United States, there are limited studies regarding use of prehospital ultrasound (US) by emergency medical service (EMS) providers. Field diagnosis of life-threatening conditions using US could be of great utility. This study assesses the ability of EMS providers and students to accurately interpret heart and lung US images.

Methods: We tested certified emergency medical technicians (EMT-B) and paramedics (EMT-P) as well as EMT-B and EMT-P students enrolled in prehospital training programs within two California counties. Participants completed a pre-test of sonographic imaging of normal findings and three pathologic findings: pericardial effusion, pneumothorax, and cardiac standstill. A focused one-hour lecture on emergency US imaging followed. Post-tests were given to all EMS providers immediately following the lecture and to a subgroup one week later.

Results: We enrolled 57 prehospital providers (19 EMT-B students, 16 EMT-P students, 18 certified EMT-B, and 4 certified EMT-P). The mean pre-test score was 65.2%±12.7% with mean immediate post-test score of 91.1%±7.9% (95% CI [22%-30%], p<0.001)). Scores significantly improved for all three pathologic findings. Nineteen subjects took the one-week post-test. Their mean score remained significantly higher: pre-test 65.8%±10.7%; immediate post-test 90.5%±7.0% (95% CI [19%-31%], p<0.001), one-week post-test 93.1%±8.3% (95% CI [21%-34%], p<0.001).

Conclusion: Using a small sample of EMS providers and students, this study shows the potential feasibility for educating prehospital providers to accurately identify images of pericardial effusion, pneumothorax, and cardiac standstill after a focused lecture.