RESUMEN
Background: Obtaining intravenous access in hypotensive patients is challenging and may critically delay resuscitation. The Graduated Vascular Access for Hypotensive Patient (GAHP) protocol leverages intraosseous fluid boluses to specifically dilate proximal veins. This study aims to evaluate the efficacy of GAHP in maximizing venous targets through early distal intraosseous access and a small fluid bolus. Methods: This was a prospective randomized cadaveric pilot study to evaluate extremity venous engorgement during intraosseous infusion. Cadavers (n = 23) had an intraosseous needle inserted into four sites: distal radius, proximal humerus, distal femur, and distal tibia. Intraosseous saline was rapidly infused, venous optimization was measured using real-time ultrasound. Primary outcome was maximum vessel circumference increase with intraosseous infusion. Secondary outcomes were: time to maximum circumference, and infusion volume required. Statistical analyses included Levene's test for equality of variances, Wilcoxon signed-rank test, and generalized estimating equation. Results: There was a significant mean increase of 1.03 cm (95% CI 0.86, 1.20), representing a difference of 102%. We found no significant difference in time to optimize vessel circumference across sites, but volume required significantly differed. Conclusion: GAHP quickly and effectively increased the circumference of anatomically adjacent veins. Anatomical sites did not differ on time to reach maximum enlargement of vessels following intraosseous infusion but did differ in terms of volume required to maximize vessel circumference. Further research is needed using live, hypotensive patients.
RESUMEN
BACKGROUND: Intramedullary implants are an increasingly common method for fixation of metacarpal fractures. Numerous techniques for instrumentation have been described with varied consideration for the risk of extensor tendon injury. The current cadaveric study evaluates the prevalence and degree of extensor tendon injury and compares percutaneous approaches with different drilling techniques. METHODS: Ninety-six metacarpals (thumbs excluded) from 24 fresh-frozen cadaveric upper extremities were used to compare 2 percutaneous approaches and 2 drilling techniques. This resulted in 4 subgroups available for comparison: oscillate to bone (OB), forward to bone (FB), oscillating through the skin (OS), and forward through the skin (FS). After instrumentation, the extensor tendons were dissected and disruption was characterized. The main outcome measures were tendon "hit rate" and relative extensor tendon defect width. RESULTS: Tendon hit rate was significantly higher in the long finger (LF), that is, 79.2%, compared with other metacarpals: index finger, 20.8%; ring finger, 12.5%; and small finger 25%. The mean relative tendon disruption was significantly less in the OB group (16.05%) compared with the other groups: FB (31.84%), FS (31.50%), and OS (29.85%). CONCLUSION: Retrograde intramedullary screw fixation of metacarpal fractures can be performed using percutaneous approaches without a significant disruption of the extensor mechanism. Instrumentation through a longitudinal stab incision down to the metacarpal head and the use of drill oscillation minimize injury to the extensor tendons. The LF extensor tendon is most at risk with retrograde intramedullary implant placement.