Analgesia in pediatric trauma patients in physician-staffed Austrian helicopter rescue: a 12-year registry analysis

In the 12-year time frame, HEMS responded to 176,056 patients including 14,425 (8.2%) children younger than 15 years (Fig. 3). Primary missions accounted for 12,324 (85.4%) pediatric cases. Of the 31.4% (n = 3874) children receiving analgesic drugs, non-trauma (n = 696) and on-site anesthetized children (n = 293) were excluded, thus resulting in 2885 patients for further analysis.

Based on the assumption that different age groups have specific needs, we identified 443 children (15.4%) under 6 years, 902 (31.3%) between 6 and 10 years, and 1540 (53.4%) between 11 and 14 years (Fig. 3). Emergency characteristics, pain levels, administered analgesia and additional interventions are shown in Table 1. Approximately two thirds were male and one third female. Median NACA score was 3 (3–4) regardless of age, and approximately 70% presented with one injured body region only.

Children < 6 years suffered more frequently from head or chest injuries, while lower extremity and spine injuries were more frequent in the older age groups (Table 1). Intravenous lines where less often placed in the youngest age group (74.3% vs. 90.7% and 90.8%). In 396 HEMS operations (13.7%) vital signs monitoring was spared.

In total, 2829 (98.1%) received an opioid and/or Esketamine. The analgesic concept typically chosen by HEMS physicians was a monotherapy with an opioid (n = 1277) or Esketamine (n = 1187), while the combination of both drugs (n = 324) was less frequently used (Table 1). Opioid use increased and Esketamine use decreased with age, regardless of injury localization (Fig. 1). Yet, Esketamine was more often administered in extremity (57.3%) than in head (41.5%) or spine injuries (32.3%). The most frequently administered opioid was Fentanyl followed by Piritramide and Morphine. The preferred use of Fentanyl vs. Piritramide was most evident in the youngest age group. Dosages predominantly increased adequately with age (Table 2). Merely Fentanyl dosages did not differ significantly between the two youngest age groups (p = 0.223). Despite also identical median dosages in the two youngest age groups, Esketamine dosages differed significantly due to differing interquartile ranges (p = 0.006).

Administration safety was evaluated by the development of MEES-Scores, respiratory rates and SpO₂ of patients receiving opioids or Esketamine (n = 2829). Measures between on-site arrival of the emergency physician and in hospital handover were compared. Unfortunately, merely < 10% of all missions featured complete documentation in this regard. Particularly documentation of patient data on handover in hospital were scarce (n = 156 (5.5%) for MEES-Scores, n = 257 (9.1%) for respiratory rates, n = 262 (9.3%) for SpO₂). For the sake of completeness, data are shown in Fig. 2, but due to abovementioned reasons sincere conclusions cannot be drawn from these data alone. Importantly, NACA scores were significantly higher in patients with a complete dataset (4 (3–4) vs. 3 (3–4); p < 0.001) indicating a more severe condition and possibly a higher risk for side effects. Noteworthy, of the 2829 children receiving opioids or Esketamine, 1918 (67.8%) had an entry in respiratory measures required during transport. Hereof, 1216 (63.4%) required no additional measures, 691 (36.0%) oxygen supplementation and merely 2 (0.1%) tracheal intubation. The analyzed registry included 293 injured children receiving analgesics and requiring intubation on-site. Hereof, 78.8% were classified as NACA ≥ 5 (median 5; IQR 5–5), translating to acute danger, respiratory and/or cardiac arrest or death.

Efficacy of analgesics was evaluated by comparing pain levels between on-site arrival of the emergency physician and in hospital handover of patients receiving opioids or Esketamine. However, documentation quality was even lower in this regard (< 8% complete documentation). Therefore, we resigned from further analysis.

Analgesia provided by HEMS in adults has been reported in military and civilian settings [5, 14‐23]. Although there is evidence that pain treatment in children is insufficient [8‐11], literature focusing on analgesia in children transported by HEMS are spare [24‐26]. Since the HEMS setting differs significantly from ground EMS work, data may not be compared between both rescue systems. Further interfering with comparability are discrepancies in age thresholds when defining a patient to be pediatric. While these thresholds varied from – as in this study – 14 [26], to 15 [24, 25, 27, 28], 18 [6, 29, 30] or 20 years [8], some studies also excluded patients under 3 years of age [29]. The relative amount of pediatric emergencies encountered by EMS is typically low, accounting for 13–25% of all patients [6, 30]. In our study, we found only 8% of all missions dedicated to children with a high injury severity. As expected and shown in studies before, two thirds of the injured children were male [6, 24, 28].

The proportion of children receiving analgesics was 31%. Primarily depending on qualification and competencies of EMS personnel and inclusion criteria, this fraction has been reported from as low as 0.3% for a paramedic staffed EMS up to 92% for critical care physician staffed EMS units [9, 24, 30, 31]. Even when suffering from fractures, only some 10–37% of children are estimated to receive analgesics prehospitally [8, 32, 33]. Compared with a recent study from Australia including only severely injured children transported by ground or air-medical services to a pediatric trauma center IV line placement was about twofold higher in this study [28]. This is of special interest, as a lack of IV access has been shown to decrease frequency of analgesia in pediatric patients [24, 29]. Alternative administration routes such as intraosseous or intranasal application devices are still infrequently used [29].

The majority of children receiving analgesic drugs were injured, which is in line with previous studies describing proportions of 53–76% of all children requiring EMS to be injured [6, 34, 35]. The most common analgesic regimens were a mono therapy with opioids or Esketamine followed by a combination therapy of opioids and Esketamine. Fentanyl was the most commonly administered opioid with its preference also described by Johnson et al. [24]. With increasing age, opioids were used more frequently, while the use of Esketamine decreased. Although this trend was independent of injury localization, Esketamine was more often administered in extremity than in head or spine injuries. Controversies about the use of Ketamine in head injuries still prevail [36, 37]. The liberal use of the racemate Ketamine or its enantiomer Esketamine in an EMS setting, particularly with regard to its use in children is a priori dependent on national and regional regulations. In Austria, Esketamine is predominantly used over the racemate Ketamine since 10 + years due to its better side-effect profile [38]. Similar to the data presented here, a study from London, UK, stated that Ketamine was the preferred medication for on-scene pediatric analgesia [36].

With regard to opioids, many studies have shown their insufficient use in children in EMS settings. Fractions range from 2 to 32% of injured children to receive opioids [8, 9, 29, 32, 39‐41] or 15% of severely injured children in HEMS to receive Ketamine or Fentanyl [25]. In our study, nearly all (> 95%) children who received analgesia, received an opioid and/or Esketamine. This high proportion of potent analgesics among injured children receiving any kind of analgesia stands in strong contrast to other studies describing opioid use in merely 13% of children receiving analgesia for fractures [32]. A decreased fraction of analgesia, in particular of opioid use in the youngest children (< 5 years), as seen in the presented data, has been described before [24, 27, 39, 41] and has led to numerous pleas demanding that also neonates and young infants should receive adequate pain relief [7, 11].

The inadequate treatment of children suffering severe pain is under discussion [1, 42] and studies continue to demonstrate an underuse of analgesic agents, thus resulting in oligo-analgesia among pediatric patients [7‐9]. In this regard, appropriate pain assessment and documentation is acknowledged to be of utmost important [8, 11, 43] to trigger and monitor pre-hospital analgesia. Nevertheless, poor documentation of pain scores is rather common, especially among pediatric patients where documented pain is described in as few as 4% [24, 29, 44‐47]. In our study, we found the pain NRS score documented in 99% of all patients receiving analgesic drugs at the time of first contact, but only in 8% before or during handover in hospital. Therefore, sincere analysis of pain relief was deemed unsound.

Potent central analgesics, especially opioids, are feared for their potentially severe adverse events – in particular respiratory depression. In the specific HEMS setting in-cabin space and patient access is limited, thus hampering the options to interfere and treat respiratory deterioration during flight. Literature on application safety of prehospitally administered analgesics is growing both for Esketamine and opioids. The afore mentioned study from London, UK, described liberal racemate Ketamine use (mean 1 mg/kg), predominantly in awake non-trapped children with blunt trauma [36] and did not demonstrate any major side effects, especially with regard to loss of airway patency. These findings were in line with another small study (n = 40) reporting no adverse events of Ketamine during air transport [48]. Concerning opioids, two studies showed no substantial respiratory depression, hypotension or other clinically significant adverse effect attributable to Fentanyl (1–3 µg/kg) in pediatric air-transported trauma patients [26, 44]. Especially the use of pain protocols addressing pain medication were shown to safely and effectively increase the frequency of analgesia without causing any major side effects [24, 44]. It is noteworthy that pediatric analgesia in our study was not driven by elaborated protocols. Moreover, HEMS in Austria is typically physician staffed and the vast majority of HEMS physicians (80%) are trained anesthesiologists with specific training in prehospital emergency medicine. The development of MEES-Scores, respiratory rates and SpO₂ values in children not requiring mechanical ventilation on-site, indicated application safety but data was too incomplete to draw sincere conclusions. However, more than two-thirds of children receiving opioids or Esketamine had an entry in respiratory measures required during transport. Hereof, nearly two-thirds did not require any additional measures at all, and more than one-third merely received oxygen supplementation during transport. Of course, severe side effects causing immediate intubation on-site may have been missed in our analysis as on-site intubated patients were primarily excluded. Additional analysis however revealed, that from the 293 injured children receiving analgesic medication and requiring intubation on-site, 78.8% were classified as NACA ≥ 5. Therefore, we truly believe that intubation was indicated by injury severity rather than medication side effects. In accordance with existent literature, we assume application safety of potent analgesics, when administered by protocol or by an experienced physician.

Complete documentation, including both values from initial on-site evaluation and later arrival in hospital was present only in 156 cases regarding MEES-Scores (5.5%), 257 cases regarding SpO₂ values (9.1%), 262 cases regarding respiratory rates (9.3%) and n = 220 cases regarding pain levels (7.9%). As mentioned before, poor documentation quality is not uncommon in emergency settings and reporting bias can therefore not be excluded. Furthermore, pain levels were documented by utilizing an NRS guided scale but not by exact numeric documentation. As children may often not be capable of adequately assessing an NRS, we must assume that pain-levels were often approximated by the HEMS-physician. As a result, detailed analysis of pain reduction was therefore not possible. Also due to incomplete documentation, weight dependent dosages of administered analgesia could not be specified. Furthermore, data analysis in general was conducted retrospectively.