Is it just HOCUS POCUS or can tele-ultrasound contribute to patient care?
In recent years, the technology of performing point-of-care ultrasound (POCUS) has become increasingly accessible and has found increasing application in ambulances, helicopters, wilderness, and other resource-limited settings. POCUS can provide valuable insights in time-sensitive, life-threatening conditions, which reduces time-to-diagnosis, ultimately affecting clinical decision-making and patient outcomes. POCUS is dependent upon the operator and, though evidence has shown that an acceptable standard of competency of prehospital ultrasound can be taught relatively quickly to non-physician personnel, such as paramedics, the feasibility of prehospital tele-ultrasound performed by non-physician personnel is unclear.
This scoping review aimed to address this by qualitatively analysing data obtained from 1 January 2010 to 31 December 2021, in the MEDLINE, EMBASE, and Cochrane online databases. The review was focused on prehospital personnel considering the benefits and costs of implementing tele-ultrasound in their practice and standards of care. The search included variations on terms such as ‘ultrasound,’ ‘tele-ultrasound,’ ‘paramedic,’ ‘emergency,’ ‘sonography,’ and ‘prehospital’. A total of 10 articles met the inclusion criteria.
Generally, the articles could be classified into three major groupings:
Unfortunately, the heterogeneity in the study design, technologies used, and the amount of ultrasound training for the paramedics, prevented cross-comparisons of different studies. This meant that the review could only provide a descriptive analysis without a formal bias assessment, thus limiting the findings.
The authors concluded that tele-ultrasound has the potential to improve ultrasound accessibility. However, there are still technological barriers to overcome and much more research is required—an opening for a budding researcher for sure!
Pause for breath…or just pause?
The 30:2 strategy of cardiopulmonary resuscitation (CPR) requires chest compressions to be paused to optimise bag-valve-mask ventilation. However, despite significant developments in evidence for resuscitation more generally, no previous studies have verified if ventilations are effectively delivered during such pauses in CPR. The team in this study undertook secondary analysis of clinical and continuous cardiac monitor data from six sites participating in the 30:2 arm of the Resuscitation Outcomes Consortium (ROC) CCC clinical trial (Trial of Continuous Compressions versus Standard CPR in Patients with Out-of-Hospital Cardiac Arrest) in North America.
During the initial prospective arm of the study, cluster-crossover randomisation was used to assign emergency medical services (EMS) agencies to use either continuous chest compression CPR or 30:2 CPR before placement of an advanced airway. This secondary study reviewed the data for those in the 30:2 arm in situations where the defibrillator had the ability to measure bioimpedance ventilation waveforms. The team had previously developed and validated criteria specifying ventilation bioimpedance waveform characteristics associated with lung inflation, and developed computer software that could automatically identify ventilation waveforms from defibrillator recordings. This specific ventilation detection method has a sensitivity of >90% and a positive predictive value of >90% compared with capnography.
The cohort available for analysis comprised 1976 people, with a mean average age of 65 years, and a 66% male predominance. The mean duration of 30:2 CPR was 9.8 (±4.9) minutes from the start of chest compressions until placement of an advanced airway. During this period, the team identified nearly 27 000 pauses in compressions! For most patients (n-1177), lung inflation waveforms were evident in <50% of those pauses. This suggests that pauses do not have detectable ventilation, suggesting sub-optimal ventilation and oxygenation during the initial management with a bag-valve-mask. Most importantly, patients where ventilation was recorded in >50% of the pauses had higher rates of prehospital return of spontaneous circulation (40.7% versus 25.2%; P<0.0001), survival to hospital discharge (13.5% versus 4.1%; <0.0001), and survival with favourable neurological outcome (10.6% versus 2.4%; P<0.0001).