Pulse oximetry may help catch vascular injury after limb trauma

Pulse oximetry may be a useful adjunctive diagnostic test after limb trauma, such that waveform abnormalities or a drop in oxygen saturation (SpO₂) could be indicative of vascular disruption, a new study has found.

The study included 99 patients (mean age 40 years, 77.8 percent) whose relevant data were drawn from electronic medical records. Vehicular incidents accounted for most limb injuries (43 percent), majority of which were in the lower extremities (72 percent). Thirty-one patients also had documented vascular disruption, while the remaining 68 did not.

Pulse oximetry showed that in those with vascular disruption, the mean SpO₂ in the injured limb was 93.9 percent, as opposed to 98.8 percent in participants without vascular disruption (p=0.034).

Moreover, the SpO₂ difference between the injured and uninjured limbs was significantly greater in patients with vs without vascular disruption (–3.86 vs 0.300; p=0.042).

Receiver operating characteristic curve analysis revealed that SpO₂ of the injured limb had an area under the curve (AUC) of 0.811, while the SpO₂ difference between the injured and uninjured limbs had an AUC of 0.857. According to researchers, both measures showed satisfactory performance for predicting vascular disruption.

Moreover, at an optimum cutoff of 95.5 percent, the sensitivity and specificity of SpO₂ for predicting vascular disruption is maximized, with corresponding values of 78 percent and 90 percent.

“The authors recommend applying the pulse oximeter to the great toe of the injured limb during the primary (or secondary) survey and recording the findings. While other clinical examinations of the limb should be carried out for completeness, an abnormal waveform and SpO₂ of less than 96 percent should warrant urgent intervention,” the researchers said.