Feasibility study of minimally trained medical students using the Rural Obstetrical Ultrasound Triage Exam(ROUTE)in rural Panama

BACKGROUND:Maternal and infant mortality rates reported in rural Panama are greater than those in urban regions.Bocas del Toro is a region of Panama inhabited by indigenous people at greater risk for pregnancy-related complications and deaths due to geographic isolation and limited access to health care.Portable ultrasound training programs have recently been implemented in low-resource settings to increase access to diagnostic imaging.The goal of this study is to determine the feasibility of teaching firstyear medical students the Rural Obstetrical Ultrasound Triage Exam(ROUTE)to help identify pathology in pregnant women of the Bocas del Toro region of Panama.METHODS:Eight first-year medical students completed ROUTE training sessions.After training,the students were compared to professional sonographers to evaluate their accuracy in performing the ROUTE.Students then performed the ROUTE in mobile clinics within Bocas del Toro.They enrolled women pregnant in their 2nd or 3rd trimesters and measured biparietal diameter,head circumference,amniotic fluid index,fetal lie and placental position.Any abnormal measurement would be further analyzed by the lead physician for a potential hospital referral.RESULTS:A total of 60 women were enrolled in the study.Four women were detected as having a possible high-risk pregnancy and thus referred to a hospital for further evaluation.CONCLUSION:Based on our data,first-year medical students with additional training can use the ROUTE to identify complications in pregnancy using ultrasound in rural Panama.Additional studies are required to determine the optimal amount of training required for proficiency.

Assessment of clinical dehydration using point of care ultrasound for pediatric patients in rural Panama

BACKGROUND: Dehydration and its associated symptoms are among the most common chief complaints of children in rural Panama. Previous studies have shown that intravascular volume correlates to the ratio of the diameters of the inferior vena cava(IVC) to the aorta(Ao). Our study aims to determine if medical students can detect pediatric dehydration using ultrasound on patients in rural Panama. METHODS: This was a prospective, observational study conducted in the Bocas del Toro region of rural Panama. Children between the ages of 1 to 15 years presenting with diarrhea, vomiting, or parasitic infection were enrolled in the study. Ultrasound measurements of the diameters of the IVC and abdominal aorta were taken to assess for dehydration. RESULTS: A total of 59 patients were enrolled in this study. Twenty-four patients were clinically diagnosed with dehydration and 35 were classified to have normal hydration status. Of the 24 patients with dehydration, half(n=12) of these patients had an IVC/Ao ratio below the American threshold of 0.8. Of the remaining asymptomatic subjects, about half(n=18) of these subjects also had an IVC/Ao ratio below the American threshold of 0.8.CONCLUSION: Our study did not support previous literature showing that the IVC/Ao ratio is lower in children with dehydration. It is possible that the American standard for evaluating clinical dehydration is not compatible with the rural pediatric populations of Panama.

Ultrasound diagnosis of malaria: examination of the spleen, liver, and optic nerve sheath diameter

BACKGROUND: Over 90% of all cases of malaria worldwide occur in Africa. Current methods of diagnosis are time and labor intensive, and could lead to delayed treatment.METHODS: In this study we investigated the effectiveness of measurements of spleen, liver, and optic nerve sheath diameter(ONSD) in identifying patients with malaria or severe malaria through the use of hand-held ultrasound devices. We recruited 40 adult patients with malaria and 16 adult control subjects at two hospitals in Mwanza, Tanzania. Ultrasonographic diagnosis was compared with rapid antigen diagnostic test and peripheral blood smear as the gold standards. An receiver operating characteristic curve test was performed to determine the most optimal diagnostic threshold for malaria and severe malaria, using each of the measurements for liver size, spleen size, and ONSD. The thresholds were determined to be >12 cm for spleen length and >15.1 cm for liver length, whereas ONSD was not signifi cant in this study.RESULTS: The sensitivities for malaria diagnosis were 66.7% and 58.3% for liver and spleen length respectively, suggesting that these measurements may not be suitable for identifying patients with severe malaria. However, the high specificity of 90.9% for spleen length and the acceptable specifi city of 75.0% for liver length suggest that these measurements can be used as a method to eliminate false-positive diagnoses(i.e. patients who do not have severe malaria but are classifi ed as having it by a test with a high sensitivity), giving a high positive predictive value.CONCLUSIONS: We report a high specifi city for spleen size and a moderate specifi city for liver size in the ultrasonographic diagnosis of severe malaria. Thus when paired with a highly sensitive method of malaria diagnosis, ultrasonographic measurement of spleen and liver size is promising as part of a diagnostic algorithm for malaria. It could be used to stratify risk in patients diagnosed with malaria and assist in their triage. If no sensitive tests are available, ultrasound might be useful to suggest malaria as a cause of a patient's constellation of clinical symptoms.