In this retrospective study we found that most patients were not referred to palliative care both in the months leading up to their final ICU admission or even during it. In the small proportion of patients who were referred to palliative care, the referral was done very late when patients were days away from death. The study showed that the use of a palliative care referral “trigger” tools would have identified a high proportion of patients who may have benefitted from palliative care referral, consistent with findings from other studies. (7, 25, 26, 27, 28, 29)
Our results indicate that 75% of patients were unknown to palliative care in the lead up to their ICU admission. (13, 17)
Furthermore, results showed that only 56% (n = 84) patients were referred to palliative care during their ICU admission and out of these 29 patients were previously known to palliative care. This means that whilst in ICU 55 patients were referred to palliative care for the first time. We can also see that all the referrals done in ICU were made quite late into the admission. Out of the 84 patients that were referred 52, 62% were referred to palliative care on the day of their death.
The results from the retrospective application of trigger tools to the data suggests that there is a large proportion of patients who could have been identified for a palliative care referral and all the benefits that come with it, both before ICU admission and during it. The use of trigger tools in an outpatient setting suggests that between 59–71% of patients should have been seen by palliative care prior to their ICU admission. These patients may have benefitted from advance care planning and shared decision making which may have impacted on the decision for ICU. (13, 17) Additionally this data shows us that the vast proportion of cancer patients warrant palliative care reviews many months before becoming acutely unwell and requiring admission to ICU. This is also reflected in a trigger tools study conducted by Gemmell et al, which found a high percentage of cancer patients warranted a palliative care assessment earlier on in their disease trajectory (29). Looking at the use of trigger tools during ICU admission, we can see that 140 to 148 patients met the criteria for a palliative care referral whilst in ICU, which is more than double the number of patients that were referred in this cohort.
Whilst all the trigger tools picked up higher numbers of patients to refer to palliative care, they also identified patients for referral at an earlier stage. All the patients that were identified by the three trigger tools during ICU admission, were positive from the day of ICU admission. This meant that the median number of days between becoming positive for BMJ and Hua et al trigger tools and death was 8, compared to actual practice where most patients were referred to palliative care on the day of death. This would have allowed more time for patients and their families to benefit from a palliative care review and could have had a positive effect on patient care. (13, 14, 17)
The selected trigger tools for this study were found through extensive literature searches, as described above. The tools were selected as they not only appeared to be most relevant to our cohort but were also backed by the most robust evidence (7, 16, 28, 29, 30). The Hua et al and BMJ trigger tools, were used on more general ICU populations and hence have an evidence base in the group. However, as this study has investigated ICU patients who have cancer, there are a few triggers that are less relevant and others which are more likely to be positive due to the patient demographic. For example, we found that no patients were positive for “Admitted from a nursing facility”, whilst triggers relating to advanced or metastatic cancer were positive in 93–94% of the patients. Future research is needed to refine palliative care referral criteria which are specific for a cancer population. The ICU specific tools (Hua Tool and Zalenski Tool) identified a similar proportion of patients for referral as the non-ICU specific Royal Marsden Tool which has been previously tested in the outpatient setting. This may suggest that it is the use of a targeted approach to the identification of patients for referral that matters most, rather than differences between the actual items included in the tools.
One of the main limitations of this study was that the data were collected retrospectively therefore is very reliant on the accuracy, completeness and quality of documentation. Also, regarding the trigger tools themselves, although most of the “triggers” were objective, there were also some subjective “triggers”. Therefore, the results may include some bias on part of the data collector and may have varied if purely objective “triggers” had been used, such as “Team perceived need for palliative care”. For example, one of the triggers included in both the Hua and Zolenski Tools used in part 2 was around having advanced/metastatic cancer. Although this is quite clear cut in solid organ tumours, it is more difficult to define in haematological malignancies so was down to the authors’ discretion on a case by case basis. It could be also argued that the findings are limited to the results of a single, tertiary centre. However, the authors believe that the findings have wider applicability and add to the growing evidence which supports the use of palliative care referral trigger tools.