Potential Use of Pulse Oximetry for the Diagnosis of Testicular Torsion

Scrotal Doppler ultrasonography (scrotal US) has been commonly used for evaluating patients with suspected testicular torsion (TT).^1,2 However, scrotal US is not available in all medical facilities. Comparatively, pulse oximetry is easily available at all institutions; it is used for monitoring pulse oximeter saturation (SpO₂) with an accuracy equivalent to that of conventional arterial oxygen saturation (Sao₂) and is the standard for noninvasive Sao₂ monitoring in most medical facilities.³ We evaluated the SpO₂ and pulse rate (PR) values on the scrotums of patients undergoing exploration for TT to determine whether these values are feasible for monitoring testicular viability in TT.

This study was a prospective case series. After the institutional review board approval was obtained, data of patients scheduled to undergo scrotal exploration for suspected TT, including their clinical history; physical examination; scrotal US, surgical, and pathological findings; and the average SpO₂ and PR values were recorded.

For obtaining SpO₂ and PR, patients were initially placed in the supine position. The pulse oximeter (OxiMax N-65; Tyco Health Care Group) was attached with an adhesive sensor pad on the scrotal skin surface overlying the affected testes. The contralateral side (normal testis or control) was monitored in the same manner as the affected side (Figure). Mean SpO₂ and PR values were obtained from the average of the individual measures at 3 points, as recorded by the senior urologists at our center. A Wilcoxon signed-rank test was used to evaluate the significance of the differences in the estimated SpO₂ values and PRs between the affected and control sites.

Sixteen patients (mean [SD] age, 9.2 [5.8] years; range, 1-19 years) who were consecutively undergoing scrotal exploration were recruited for the study. The symptom onset occurred within 24 hours (mean [SD], 13.6 [4.5] hours; range, 3-22 hours). Painful and swollen or erythematous scrotum was reported in 11 patients and scrotal pain, in 5 patients. No blood flow signals were detected by scrotal US in any of the torsed testes. Good-quality signals for SpO₂ and PRs were obtained in all normal testes. In all of the affected testes, both SpO₂ values and PRs were undetectable. Differences in the SpO₂ values and PRs between the affected and control sites are shown in the Table. There were statistically significant differences in SpO₂ values and PRs between testes with TT and normal testes.

Pulse oximetry measures the ability of oxygenated hemoglobin to reflect light at different wavelengths.^4-6 Our results demonstrate that SpO₂ values and PRs were undetectable in all of the torsed testes, in contrast to that in normal subjects. However, it may be difficult to diagnose epididymal torsion compared with TT using pulse oximetry, as the epididymis is relatively difficult to locate owing to its small size. This shortcoming may be overcome with subsequent improvements in oximetry techniques.

In conclusion, pulse oximetry can be used for monitoring hemodynamic changes of the affected testis attributed to its small apparatus design, noninvasiveness, and general availability. In comparison, the estimate of the cost of pulse oximetry is around $600, which is 1.2% of the cost of Doppler US. Therefore, it can be useful in resource-constrained settings in which there is no access to US. However, future studies are warranted to evaluate the test characteristics of pulse oximetry for detecting TT based on using US and surgical findings as the gold standards and, nonetheless, to reliably differentiate among the various conditions of acute scrotum such as torsed appendage or epididymo-orchitis.

Corresponding Author: Hsiao-Wen Chen, MD, Division of Urology, Chang Gung Memorial Hospital, Medical College, Chang Gung University, 5, Fushing Street, Gueishan, Taoyuan, Taiwan 333 (mhc1211@cgmh.org.tw).

Published Online: April 28, 2014. doi:10.1001/jamapediatrics.2014.86.

Conflict of Interest Disclosures: None reported.