Publications included in systematic review
| Author; country; study period | Grade of evidence; study design | Rural or urban | Inclusion criteria | CCP characteristics | Intervention | Comparison | Analysis | Adjustments | Outcomes | Findings |
|---|---|---|---|---|---|---|---|---|---|---|
| Comparison of CCP and physician-lead care | ||||||||||
| Baxt W; California, USA; Study period not specified | 3 Cohort, not specified if prospective or retrospective | Not specified | All blunt trauma patients receiving interventions by one of two HEMS crews and transport to one trauma centre. | HEMS nurse/paramedic crew. Nurse able to perform same procedures as physicians; paramedics restricted to non-RSI intubation, limited medication and IV access. | Nurse/paramedic HEMS crew (n=258) | Physician HEMS crew (faculty-level emergency physician) (n=316) | TRISS-based analysis | No further adjustment | Mortality (time not specified) | Mortality in nurse/paramedic group no different from predicted (Z +0.208) but better than predicted in physician group (Z +2.284). Difference in predicted and observed mortality significantly different between groups (p<0.05), favouring physician-led care. |
| Garner A; New South Wales, Australia; 1996–1998 | 3 Retrospective cohort | Mixed | All blunt trauma with ISS ≥10 transported by one of two HEMS to different receiving hospitals. | HEMS double paramedic crew. Competencies not specified, but do not include RSI or administration of blood products. | Paramedic HEMS crew (n=140) | Physician HEMS crew (faculty-level emergency physician) (n=67) | TRISS-based analysis | Adjusted W used, as M statistic indicated poor matches with MTOS patient cohort | Mortality predischarge (time not specified) Interventions delivered | Mortality less in physician group (8–19 additional survivors per 100 patients). Physicians performed more procedures than paramedics (intubation 34/67 vs 14/140, thoracostomy 8/67 vs 2/140, median volume of IV fluid in hypotensive patients 5035 mL vs 1475 mL). |
| Schmidt U; Germany/USA; 1988–1989 | 3 Retrospective cohort | Not specified | All trauma patients with multiple injuries in an American (USA) and a German (GER) HEMS, transporting to one respective trauma centre. | USA HEMS double paramedic/nurse crew. Competencies not specified. | USA paramedic HEMS crew (n=186) | GER physician HEMS crew (senior resident or faculty-level trauma surgeon) (n=221) | Direct comparison TRISS-based analysis | No further adjustment | Frequency of interventions. Early mortality (<6 h) Mortality (time not specified) | More interventions (intubation, intravenous fluid, thoracostomy) in GER. More early deaths in USA than GER (12 and 4, respectively). Overall mortality in GER significantly better than predicted (Z +2.459), USA not different from predicted (Z +1.049). 10.8% penetrating trauma in USA, 0% in Germany. |
| Hamman B; Kentucky, USA; 1985–1987 | 3 Retrospective cohort | Not specified | All trauma patients transported by one HEMS before and after removal of physicians from the service. | HEMS double crew of nurse/nurse or nurse/ paramedic with at least 2 years critical care experience. Same procedures as physician except cricothyrotomy and tube thoracostomy. | Non-physician HEMS crew (n=114) | Physician HEMS crew (senior resident or faculty-level emergency physician) (n=145) | TRISS-based analysis | No further adjustment | Mortality (time not specified) Interventions delivered RTS | Significantly better survival than expected for both groups (Z score +3.11 and +2.03 for the non-physician and physician group, respectively). No significant differences between the groups in trauma severity (RTS) or number and types of interventions performed. |
| Cameron S; Queensland, Australia; 1999–2003 | 3 Retrospective cohort | Not specified | All patients transported by one HEMS before and after removal of physicians from the service. | HEMS double crew of intensive care paramedics. Not able to perform RSI or invasive monitoring. | Paramedic tasking and staffing of HEMS (n=163) | Physician tasking and staffing of HEMS (emergency physician) (n=211) | Direct comparison | RTS calculated for trauma patients | Mortality at 30 days Length of hospital stay Discharge from ED Secondary transfer from receiving hospital to other facility | No difference in 30-day mortality (2.8% and 2.5%), hospital length of stay (mean of 2 and 1 days) or secondary transfers (9% and 8%) between physician and paramedic group, respectively. More discharges from ED for paramedic group than physician group (33.1% and 14.7%, p=0.0001) respectively. No difference in trauma severity (RTS) between groups. |
| Comparison of CCP and non-physician-lead care | ||||||||||
| Mabry R; Afghanistan; 2007–2010 | 3 Retrospective cohort | Mixed | All trauma with ISS >16 (civilian and military) transported by helicopter during either US Army or US Army National Guard deployment. | HEMS double critical care-trained flight paramedic (CCFP) or CCFP/EMT crew | CCFP HEMS crew (n=202) | US Army MEDEVAC HEMS with single emergency technician (n=469). Flight surgeon on board for unspecified number of missions. | Multivariate logistic regression model | Adjusted for ISS, incident location, season and patient category | Mortality at 48 h | Mortality 8% and 15% in CCP and paramedic group, respectively. After adjusting for covariates, 48-h mortality significantly lower with CCFP treatment (OR 0.34). No difference in trauma severity (ISS) between the groups. |
| Mitchell A; Nova Scotia, Canada; 1998–2002 | 3 Retrospective cohort | Rural | All blunt trauma patients (aged >15 years) with ISS ≥12 transported to one tertiary trauma centre. Includes secondary transfer. | HEMS CCP and registered nurse crew | HEMS transport (n=237, 84% secondary transfers) | Paramedic ground transport (n=554, 44% secondary transfers) | TRISS-based analysis | Insertion of normal physiological values where data was missing. | Mortality (time not specified) | Significantly lower mortality than predicted with CCP HEMS transport (Z +2.77), significantly higher mortality than predicted with ground transport (Z −1.99). 6.4 more survivors than expected per 100 patients in HEMS group, 2.4 unexpected non-survivors per 100 patients in ground group. |
| Kerr W; Maryland, USA; 1988–1995 | 3 Retrospective cohort | Not specified | All trauma transported to one trauma centre. Includes 17% secondary transfer. | HEMS single paramedic crew with additional training including use of ventilators, EtC02 monitoring, ETI, IO access, needle thoracostomy and cricothyrotomy. | HEMS transport (n=11 623) | Paramedic ground transport (n=11 379) | direct comparison of ISS-stratified groups | No further adjustment | Mortality predischarge (time not specified) | Mortality for ISS <31 was 4.1% and 3.1% for HEMS and ground transport, respectively (p<0.001). Mortality for ISS ≥31 was 37.1% and 45.3% for HEMS and ground transport, respectively (p<0.001). |
| Wirtz M; State of New York, USA; 1992–1999 | 3 Retrospective cohort | Not specified | All trauma patients >15 years old with ISS > 9, transported by two different HEMS to one trauma centre. Includes secondary transfers. | HEMS nurse/paramedic crew (both with critical care competencies) | Nurse/paramedic HEMS crew (n=220) | Nurse/nurse HEMS crew (n=841) | TRISS-based analysis | No further adjustment | Mortality (time not specified) | No difference in mortality between the groups. No difference in mortality compared with predicted (Z +1.27 and −0.94 for nurse/paramedic and nurse/nurse care, respectively). |
| Evaluation of added skills for CCPs | ||||||||||
| Bernard S; Victoria, Australia; 2004–2008 | 2 Prospective, randomised controlled trial | Urban | All patients with head injury, GCS <9, intact airway reflexes and age >15 attended by an intensive care (MICA) paramedic. | MICA paramedics on ground vehicle | RSI by MICA paramedic (n=160) | RSI in receiving ED (n=152) | Intention to treat | No further adjustment | Extended Glasgow Outcome Scale (GOSe) at 6 months | GOSe at 6 months not significantly different (median 5 and 3 for MICA RSI and ED RSI, respectively, p=0.28). Secondary outcome ‘good neurologic outcome’ (GOSe 5–8) significantly better for MICA RSI (51% and 39%, respectively, p=0.046). |
| York D; Illinois, USA; 1988–1990 | 3 Retrospective cohort | Not specified | All chest trauma transported to one level 1 trauma centre. Includes secondary transfer. | HEMS paramedic working with flight nurse. Paramedic training or competencies not further specified. | Tube thoracostomy by HEMS paramedic/flight nurse (n=72) | Tube thoracostomy in hospital after ground transport (n=100) | Direct comparison | No adjustments | Complications (bleeding, misplacement or infection) ISS and trauma score Mortality | No difference in complication rates. Unadjusted mortality significantly higher in HEMS group than hospital group (29/72 and 14/100, respectively). ISS and trauma score worse in HEMS group (39 and 27; 7 and 10, respectively). No mortality comparison after adjustment for trauma severity. |
| Gardtman M; Sweden; 1990–1996 | 3 Retrospective cohort | Urban | All patient with clinical diagnosis of pulmonary oedema attended by a mobile coronary care unit (MCCU). | MCCU paramedic ± nurse crew | Prehospital care with heart failure protocol including non-invasive ventilation (n=158) | Prehospital care before heart failure protocol (n=158) | Direct comparison Kaplan–Meier curve for survival | No further adjustment | Physiologic and clinical findings at hospital arrival Mortality predischarge and at 1 year 1-year cumulative morbidity | Physiologic parameters unchanged, but significant improvement in clinical picture of pulmonary oedema. No difference in predischarge or 1-year mortality (18% and 18%, 39.2% and 35.8% before and after implementation of heart failure protocol, respectively). No difference in morbidity over one year follow-up. |
CCP, critical care paramedic; ED, emergency department; ETI, endotracheal intubation; GCS, Glasgow Coma Scale; HEMS, helicopter emergency medical service; ISS, Injury Severity Score; MICA, mobile intensive care ambulance; MTOS, Major Trauma Outcome Study, used as comparator in TRISS analysis; M-value, indicates how well study population matches that of the Major Trauma Outcome Study (TRISS analysis); RSI, rapid sequence induction of anaesthesia and tracheal intubation; RTS, Revised Trauma Score; TRISS, Trauma and Injury Severity Score (determines the probability of survival of a patient); W-score, Number of unexpected survivors or unexpected non-survivors (TRISS analysis); Z-score, statistically significant difference in mortality if higher than +1.96 or lower than −1.96 (TRISS analysis).