Nijhoff, M. (Maaike) (2018) Validation of the DCD-N score and a linear prediction model to identify potentialcandidates for donation after circulatory death: a nation-wide cohort study. thesis, Medicine.
Full text available on request.Abstract
Introduction: Donation after circulatory death (DCD) is a controlled procedure after planned withdrawal of life-sustaining treatment (WLST) at an intensive care unit. All donors who do not fulfil the legal criteria for donation after brain death (DBD) are considered for DCD donation. Compared to DBD donors, DCD donation exposes organs to accumulating warm ischaemic injury during the period between WLST and actual cardiac arrest (the agonal phase). The length of this phase varies widely between individual donors. Rabinstein and colleagues have created a scoring system (DCD N-score), in which points are attributed to: absence of cough reflex (two points), absence of cornea reflex (one point), absent extensor or motor reflex to pain (one point) and an oxygenation index >3.0 (one point). To have a more precise output, Rabinstein and colleagues have created another model, namely a linear prediction model. This linear prediction for donation after cardiac death model (LPDCD-model) has an output similar to the DCD-N score, but varies in input variables. Therefore, validation of both the DCD-N score and the LPDCD model may be essential to predict potential candidates for donation after circulatory death (DCD). Study aim: This multicentre retrospective study focuses on validation of the straightforward model (DCD-N score) and the LPDCD model to predict the likelihood of death within 60 minutes. Methods: For this study we analysed all patients who underwent WLST from 2010-2015 in two intensive care units in The Netherlands. This study only included patients from which their deaths had a direct causal link with their brain injury. Univariate and multivariate logistic regression analysis were used to construct predictive models for death within 60 minutes or 120 minutes as a binary outcome variable. Receiver-operator curve analysis was used to assess how well the DCD-N score and the linear prediction model predict the chance for the potential donor to die within 60 minutes or 120 minutes after withdrawal of treatment. Results: 119 out of 181 (77%) patients died within 60 minutes after WLST. Time to death after WLST ranged from 2 to 1253 minutes with a median of 27 minutes. Absent corneal reflexes (odds ratio [OR] 4.71, 95% CI 2.15 – 10.4; p=0.001), absent cough reflex (OR 3.40, 1.55 –7.47; p=0.002), extensor or absent motor responses (OR 0.74, 0.24 –2.33; p=0.609), and an oxygenation index score of more than 3.0 (OR 1.57, 0.72 –3.44; p=0.260) were found to have a predictive value for death within 60 min of WLST. After external validation of the logistic regression model (DCD-N score), a good discrimination for death within 60 minutes (AUC 0.78; 95% CI 0.70-0.85) and death within 120 minutes (AUC 0.83; 95% CI 0.77-0.90) was found. The linear prediction model showed a good discrimination for death within 60 minutes (AUC 0.81; 95% CI 0.74-0.88) and death within 120 minutes (AUC 0.78; 95% CI 0.70-0.85). Calibration of the DCD-N score was not possible due to the use of the current scoring system. Calibration of the LPDCD model shows that the validation model mostly under predicted the probability of death. Conclusions This study showed that absence of: cough reflex, cornea reflex, extensor – or motor reflex and an oxygenation index >3.0 are associated with a higher probability of death within 60 minutes. Validation of the DCD-N score and the linear prediction model showed both good discrimination, but poor calibration for the prediction of the probability of death within 60 minutes. However, clinicians can still use the DCD-N model to aid their best judgement of the probability of death within 60 minutes.
| Item Type: | Thesis (Thesis) |
|---|---|
| Supervisor name: | Faculty supervisor and Second supervisor: Moers, dr. C. and Pol, dr. R.A. and Location: University Medical Centre Groningen, department of |
| Faculty: | Medical Sciences |
| Date Deposited: | 25 Jun 2020 11:02 |
| Last Modified: | 25 Jun 2020 11:02 |
| URI: | https://umcg.studenttheses.ub.rug.nl/id/eprint/2179 |
Actions (login required)
 |
View Item |