Head injury in older adults presenting to the ambulance service: who do we convey to the emergency department, and what clinical variables are associated with an intracranial bleed? A retrospective case-control study

OBJECTIVE

Most older adults with traumatic brain injuries (TBI) reach the emergency department via the ambulance service. Older adults, often with mild TBI symptoms, risk being under-triaged and facing poor outcomes. This study aimed to identify whether sufficient information is available on the scene to an ambulance clinician to identify an older adult at risk of an intracranial haemorrhage following a head injury.

METHODS

This was a retrospective case-control observational study involving one regional ambulance service in the UK and eight emergency departments. 3545 patients aged 60 years and over presented to one regional ambulance service with a head injury between the 1st of January 2020 and the 31st of December 2020. The primary outcome was an acute intracranial haemorrhage on head computed tomography (CT) scan in patients conveyed to the emergency department (ED). A secondary outcome was factors associated with conveyance to the ED by the ambulance clinician.

RESULTS

In 2020, 2111 patients were conveyed to the ED and 162 patients were found to have an intracranial haemorrhage on their head CT scan. Falls from more than 2 m (adjusted odds ratio (aOR) 3.45, 95% CI 1.78-6.40), chronic kidney disease (CKD) (aOR 2.80, 95% CI 1.25-5.75) and Clopidogrel (aOR 1.98, 95% CI 1.04-3.59) were associated with an intracranial haemorrhage. Conveyance to the ED was associated with patients taking anticoagulant and antiplatelet medication or a visible head injury or head injury symptoms.

CONCLUSION

This study highlights that while most older adults with a head injury are conveyed to the ED, only a minority will have an intracranial haemorrhage following their head injury. While mechanisms of injury such as falls from more than 2 m remain a predictor, this work highlights that Clopidogrel and CKD are also associated with an increased odds of tICH in older adults following a head injury. These findings may warrant a review of current ambulance head injury guidelines.

Novices cannot fill the examiners' shoes: Evidence of footwear examiners' expertise in shoe comparisons

The value of a footwear examiner's opinion centres on their ability to determine whether a particular shoe made an impression with greater accuracy than a novice. However, there has been limited research on the expertise of footwear examiners and the accuracy and reproducibility of their decisions. In the current study, we measured the accuracy and consensus of 31 footwear examiners versus a comparison group of 29 novices. Participants completed 20 ground truth known mock shoe comparisons. Results demonstrated that footwear examiners were more accurate than novices, regardless of comparison difficulty. Overall, on trials where probative decisions were given, examiners made false identifications and false exclusions on a total of 3% and 2% of trials, while novices made false identifications and false exclusions on a total of 19% and 17% of trials. Examiners also demonstrated better consensus in their opinions than novices, although both groups demonstrated low levels of agreement in their responses and variability in their interpretation of the conclusion scale. In summary, these findings support the proposition that footwear examiners show expert-level performance in matching known and unknown footwear impressions. These performance estimates may help the criminal justice system to appropriately value footwear examination evidence.

Plasma prolactin concentrations during lactation, pouch young development and the return to behavioural oestrus in captive koalas (Phascolarctos cinereus)

Plasma prolactin (PRL) concentrations in captive koalas during lactation were determined by serial blood sampling. PRL concentrations were low (1.3 ± 0.1 ng mL-1; n = 5) during early lactation until pouch young (PY) began to emerge from the pouch (around Day 130) before significantly (P < 0.05) increasing between Day 161 and Day 175 (5.3 ± 1.0 ng mL-1). A significant (P < 0.001) peak in PRL (7.7 ± 0.6 ng mL-1) coincided with maturing young between Day 189 and Day 231. All females failed to exhibit any signs of oestrous behaviour until Day 268.8 ± 8.5 (n = 4), some 102 ± 19 days before PY were weaned following achieving target weights of 2.5-2.7 kg. Throughout lactation, plasma LH concentrations were relatively high (range 4.9-8.7 ng mL-1) and LH responses to exogenous gonadotrophin-releasing hormone were observed in all koalas at all times during lactation.

Use of the gonadotrophin-releasing hormone antagonist azaline B to control the oestrous cycle in the koala (Phascolarctos cinereus)

The present study examined the effectiveness of the gonadotrophin-releasing hormone (GnRH) antagonist azaline B to suppress plasma LH and 17β-oestradiol concentrations in koalas and its potential application for oestrous synchronisation. In Experiment 1, single subcutaneous injections of azaline B successfully blocked the LH response to exogenous mammalian (m) GnRH in a dose-dependent manner; specifically, 0 mg (n = 4) did not suppress the LH response, 1 mg azaline B (n = 6) suppressed the LH response for 24 h (P < 0.05), 3.3 mg azaline B (n = 8) suppressed the LH response significantly in all animals only for 3 h (P < 0.05), although in half the animals LH remained suppressed for up to 3 days, and 10 mg azaline B (n = 4) suppressed the LH response for 7 days (P < 0.05). In Experiment 2, daily 1 mg, s.c., injections of azaline B over a 10-day period during seasonal anoestrus (June-July; n = 6) suppressed (P < 0.01) the LH response to mGnRH consecutively over the 10-day treatment period and, 4 days after cessation of treatment, the LH response had not recovered. Experiment 3 was designed to test the efficacy of daily 1 mg, s.c., azaline B over 10 days to suppress plasma LH and 17β-oestradiol concentrations and ultimately synchronise timed return to oestrus during the breeding season. Although azaline B treatment did not suppress basal LH or 17β-oestradiol, oestrus was delayed in all treated females by 24.2 days, but with high variability (range 9-39 days). Overall, the present study demonstrates that the GnRH antagonist azaline B is able to inhibit the LH response in koalas to exogenous mGnRH and successfully delay the return to oestrus. However, although azaline B clearly disrupts folliculogenesis, it has not been able to effectively synchronise return to oestrus in the koala.

The use of a synthetic progesterone, levonorgestrel (LNG), to control the oestrous cycle in the koala

This study investigated the efficacy of a synthetic progestogen, levonorgestrel (LNG), to control koala ovarian activity for the purposes of oestrous synchronisation. Captive koalas were administered either saline control or a 70-mg LNG implant on Day 2 of oestrus. Urogenital cytology, oestrous behaviour and plasma oestradiol-17β and LH concentrations were monitored over a 6-week period. After LNG implant removal females were monitored to determine if the return to oestrus was synchronised. LNG-treated koalas immediately ceased displaying oestrous behaviour, showed no evidence of cornified epithelial cells in smears of urogenital cytology and exhibited low plasma oestradiol-17β concentrations throughout the implantation period. In contrast, oestradiol-17β levels in control koalas showed evidence of continued cyclic activity associated with behavioural oestrus and increased cornified epithelial cells in urogenital smears on Days 33 to 35 after saline injection. After implant removal, LNG-treated koalas exhibited oestrus at 13, 14, 17 and 30 days after implant removal. Plasma LH concentrations varied throughout the study period with no significant time (P = 0.49) or treatment (P = 0.13) effect. Overall results from this study suggest that LNG implants in koalas can inhibit oestrous behaviour and reduce circulating oestradiol-17β levels before oestrus, most likely by preventing development of the pre-ovulatory follicle. However, there was no evidence of LH suppression by the LNG implants. Removal of LNG implants resulted in the synchronous return to oestrus in three of the four treated koalas. Further studies on a larger population are required to validate these findings.

Seasonal oestrous cycle activity of captive female koalas in south-east Queensland

This study investigated the seasonality of behavioural oestrus in a captive koala population in south-east Queensland. A total of 33 sexually mature koalas were examined over a 4-year period (2009–12) to determine the possible influence of temperature, photoperiod and rainfall on the incidence of expression of behavioural oestrus without the confounding effect of lactation or limiting food resource availability. Although signs of behavioural oestrus were detected throughout the year, an obvious seasonality was apparent, with significantly fewer females displaying behavioural oestrus in late autumn and winter (May–August) than September to April (P < 0.0001). While average monthly photoperiod (P < 0.0001) and average monthly temperature (P < 0.0001) were significantly related to oestrous behaviour, rainfall was not (P > 0.05). A better understanding of the seasonality of reproductive function in the female koala will facilitate the use of reproductive management-assisted breeding technology to enable improved genetic management in captive populations.

Reproductive physiology of the female greater bilby (Macrotis lagotis Thylacomyidae): evidence for a male-induced luteal phase

Endocrinology of the oestrous cycle, pregnancy and early lactation was investigated in captive Western Australian greater bilbies (Macrotis lagotis). Initially, six females were monitored for changes in urogenital cytology, plasma progestogen, pericloacal and pouch morphology in the absence of a male. This was followed by the introduction of a male and a reproductive assessment through mating, gestation and early lactation. In the absence of a male, there was no cyclical pattern of urogenital cytology, pericloacal or pouch development, and progestogen concentrations remained basal. Within 5 days of the introduction of a male, all females had a karyopycnotic index of 100%. Spermatozoa were present in the urogenital smear within 3 days of male introduction in all five females that gave birth. Five to 9 days after the introduction of a male, there was an increase in plasma progestogen concentration that remained elevated for 14–19 days. Six of the seven females gave birth approximately 3 days after reaching peak plasma progestogen concentrations. Gestation length ranged between 14 and 17 days. Plasma progestogen concentrations of the postpartum and early lactation period were lower (P < 0.0001) than during gestation, but greater (P < 0.0001) than those recorded before the introduction of a male. One female that gave birth early in the study that was examined until weaning of the pouch young showed a cyclical pattern of plasma progestogen secretion that ended at weaning. This study provides evidence that the luteal phase in the greater bilby is induced by the presence of a male. Similar to female reproductive physiology in the Peramelidae, elevated progestogen concentration in the greater bilby was extended into lactation.