Reliability of Simple Sonographic Findings Acquired With Hand-held Apparatuses to Inform Obstetric Diagnosis

Rationale: The majority of obstetric emergencies are identified through clinical examination, which cannot be substituted by ultrasound. However, just as a laboratory exam, ultrasonograpy can provide swift point of care information on fetus presentation, viability, placenta position, quantity of amniotic fluid and presence of abdominal fluid to inform the clinical reasoning and therapeutic escalation. Ultrasound literature in low-resource settings has favoured antenatal care (ANC) rather than the emergency setting. Also, hand-held ultrasound machines may not be as performant as traditional machines used by expert operators but to date is still to be tested in a low resource setting.

Objective: to assess the reliability of ultrasound findings measured by hand held ultrasound probes used by operators with variable experience in a low resource hospital.

Hypothesis: There is substantial agreement between simple ultrasound findings identified using hand held ultrasound devices and the reference standard.

Study design: a prospective observational diagnostic accuracy study. Study population: parturients admitted to the Princess Christian Maternity Hospital (PCMH) in Freetown, Sierra Leone.

Sample size: no formal sample size calculation is performed. Based on current rates of admissions to the PCMH we expect to perform obstetrical ultrasound scan in at least 300 patients during a 2-months study period.

Methods: 4 trained physicians (3 naive and 1 intermediate ultrasound users) will perform the ultrasound investigations using the hand held device and complete a structured predefined report form of obstetric ultrasound findings at patient admission or according to clinical indications after admission. These will be compared with the reference standard, i.e. an ultrasound examination performed by a specialist gynecologist/obstetrician using a conventional apparatus in the hospital ultrasound room.

Main study parameters/primary endpoints: The mean diagnostic accuracy among nine ultrasound obstetric findings collected with hand held devices versus the reference standard.

Inclusion criteria

• Admitted to the emergency department, outpatient department, in-patient department or antenatal care (ANC) of the PCMH during the study period.
• Fulfills one or more of the five inclusion categories: i.e. vaginal bleeding in early pregnancy, pre-eclampsia, prolonged/obstructed labor, antepartum hemorrhage (APH) and other high risk pregnancies encountered in ANC.

Exclusion criteria

• Ultrasound examination not feasible, e.g., due to electricity breakdown, or physical absence or unavailability of the trained sonographers.