Making a ‘B line’ for lung ultrasound in acute heart failure
Acute heart failure (AHF) is characterised by new onset of heart failure or worsening heart failure presenting with cardiorespiratory symptoms. It is difficult to diagnose in the prehospital environment and is commonly misdiagnosed. However, lung ultrasound (LUS) may help with paramedic diagnosis.
Assessment of B-lines has been shown to be an accurate way to establish pulmonary congestion in the patient with AHF—but is it a tool that can be used by paramedics?
This was a prospective, non-randomised interventional study from the United States included adult patients (>18 years old) with an on-scene chief complaint of dyspnoea and at least one of the following—bilateral lower extremity oedema, orthopnoea, wheezing or rales on auscultation, respiratory rate >20 breaths/minute, or oxygen saturation <92%. LUS was performed when a paramedic trained in LUS was present and an ultrasound was available on the ambulance.
The LUS was defined as positive for AHF if both anterior–superior lung zones had greater than or equal to three B-lines or bilateral B-lines were visualised on a four-view protocol (you may need to look this up if you're not LUS trained–I did). Paramedic diagnosis was then compared with hospital discharge diagnosis, which served as the standard.
A total of 264 patients were included, 94 (35%) of which had a final diagnosis of AHF. Forty patients had LUS performed, 17 of whom had a final diagnosis of AHF. Sensitivity and specificity for AHF by paramedics were 23% (95% CI 0.14–0.34) and 97% (95% CI 0.92–0.99) without LUS and 71% (95% CI 0.44–0.88) and 96% (95% CI 0.76–0.99) with the use of LUS.
LUS improved paramedic sensitivity and accuracy for diagnosing AHF and led to higher rates of prehospital heart failure therapy initiation and significantly decreased time to treatment. It is worth reading the whole study to gain the broader picture.
When a 12-lead ECG costs more than money…
Minimising on-scene times for suspected stroke is one of the key components for improving outcomes, with current guidelines recommending the avoidance of interventions that add no value to the management. One such intervention is the prehospital 12-lead ECG (PHECG), which has been shown to add 4–7 minutes to the on-scene time without adding value. Despite this, a 2022 study identified that 48% of stroke patients still received a PHECG.
This study aimed to explore the views, opinions, attitudes, and decision-making of paramedics involved in undertaking PHECGs for stroke patients. It was conducted as part of a concurrent mixed-methods study investigating the use and impact of PHECGs in acute stroke patients. Data were collected through semi-structured interviews based around the cognitive continuum theory (see original article for further details) and included a total of 14 paramedics from one emergency medical service (EMS) in the South of England.
Five themes were identified during the analysis. Although it is difficult to do them justice in this short summary, the themes were as follows:
- ‘Time is brain’: minimising delays and rapid transport to definitive care
- Barriers and facilitators to undertaking PHECGs for stroke patients
- Recognising and gaining cues
- Maintaining patient dignity, self-protection and fully informed consent
- Education, experience, and engagement with evidence.
There were mixed views about the importance and usefulness of PHECGs for prehospital management of stroke patients, but all participants agreed that it should not contribute to any delays in reaching hospital. The interesting dialogue surrounds how and why paramedics choose to undertake a PHECG—particularly around how guidelines such as JRCALC are viewed (ranging from being seen as the ‘bible’ to just guidelines); the impact of a FAST-positive finding; the use of intuition and prior experience; and the potential difference between those who have taken different educational routes to registration.
For anyone interested in improving stroke care, this article makes for interesting reading.