Prognosis after traumatic brain injury

Dit proefschrift beschrijft een aantal studies op het gebied van prognose na matig ernstig of ernstig traumatisch hersenletsel (THL). In hoofdstuk 1 wordt het klinische probleem van traumatisch hersenletsel besproken. Traumatisch hersenletsel wordt gedefinieerd als elk hersenletsel dat is ontstaan door een oorzaak van buitenaf, zoals een ongeval, een val of een schotwond. THL vormt een belangrijk volksgezondheidsprobleem in de Westerse wereld; het is een van de meest voorkomende doodsoorzaken bij jong volwassenen en het kan het leven en het functioneren van jonge mensen enorm beïnvloeden. De nadruk van dit proefschrift ligt op de ontwikkeling en validatie van prognostische modellen; statistische modellen waarin individuele patiëntkenmerken worden gecombineerd om de kans op een bepaalde uitkomst of ziekte status te kunnen voorspellen. De doelstellingen betroffen: (1) het beschrijven van methodologische ontwikkelingen ten aanzien van eerder ontwikkelde prognostische modellen voor THL patiënten; (2) de ontwikkeling en validatie van nieuwe prognostische modellen die de lange termijn gevolgen voorspellen voor patiënten met matig ernstig of ernstig traumatisch hersenletsel en (3) het voorspellen van de behoefte van een THL patiënt aan behandeling in een gespecialiseerd traumacentrum om zo de triage criteria (al dan niet transporteren naar een gespecialiseerd trauma centrum) te kunnen verbeteren.This thesis describes studies on prognosis after severe or moderate traumatic brain injury (TBI). In Chapter 1, the clinical problem of TBI is discussed. TBI is generally defined as an injury to the brain caused by an external physical force, such as a traffic accident, a fall or a gunshot. TBI is an important public health care problem in the western world. It is one of the most common causes of death in young adults and it can affect people’s lives enormously. The focus of this thesis is on developing and validating prognostic models: statistical models that combine individual patient characteristics to predict the probability of a particular outcome or disease state. The objectives of this thesis were: (1) to study methodological developments in prognostic modeling in TBI; (2) to develop and validate prognostic models that predict long- term outcome for patients with severe or moderate TBI an (3) to predict the need of specialized intensive care to aid a more efficient triage of patients

Timing of elective pre-labour caesarean section: a decision analysis

__Background:__ Since caesarean sections (CSs) before 39+0 weeks gestation are associated with higher rates of neonatal respiratory morbidity, it is recommended to delay elective CSs until 39+0 weeks. However, this bears the risk of earlier spontaneous labour resulting in unplanned CSs, which has workforce and resource implications, specifically in smaller obstetric units. __Aim:__ To assess, in a policy of elective CSs from 39+0 weeks onward, the number of unplanned CSs to prevent one neonate with respiratory complications, as compared to early elective CS. __Materials and Methods:__ We performed a decision analysis comparing early term elective CS at 37+0–6 or 38+0–6 weeks to elective prelabour CS, without strict medical indication, at 39+0–6 weeks, with earlier unplanned CS, in women with uncomplicated singleton pregnancies. We used literature data to calculate the number of unplanned CSs necessary to prevent one neonate with respiratory morbidity. __Results:__ Planning all elective CSs at 39+0–6 weeks required 10.9 unplanned CSs to prevent one neonate with respiratory morbidity, compared to planning all elective CSs at 38+0–6 weeks. Compared to planning all elective CSs at 37+0–6 weeks we needed to perform 3.3 unplanned CSs to prevent one neonate with respiratory morbidity. __Conclusion:__ In a policy of planning all elective pre-labour CSs from 39+0 weeks of gestation onward, between three and 11 unplanned CSs have to be performed to prevent one neonate with respiratory morbidity. Therefore, in our opinion, fear of early term labour and workforce disutility is no argument for scheduling elective CSs <39+0 weeks

Regional differences in severe postpartum hemorrhage: A nationwide comparative study of 1.6 million deliveries

Background: The incidence of severe postpartum hemorrhage (PPH) is increasing. Regional variation may be attributed to variation in provision of care, and as such contribute to this increasing incidence. We assessed reasons for regional variation in severe PPH in the Netherlands. Methods: We used the Netherlands Perinatal Registry and the Dutch Maternal Mortality Committee to study severe PPH incidences (defined as blood loss ≥ 1000 mL) across both regions and neighborhoods of cities among all deliveries between 2000 and 2008. We first calculated crude incidences. We then used logistic multilevel regression analyses, with hospital or midwife practice as second level to explore further reasons for the regional variation. Results: We analyzed 1599867 deliveries in which the incidence of severe PPH was 4.5%. Crude incidences of severe PPH varied with factor three between regions while between neighborhoods variation was even larger. We could not explain regional variation by maternal characteristics (age, parity, ethnicity, socioeconomic status), pregnancy characteristics (singleton, gestational age, birth weight, pre-eclampsia, perinatal death), medical interventions (induction of labor, mode of delivery, perineal laceration, placental removal) and health care setting. Conclusions: In a nationwide study in The Netherlands, we observed wide practice variation in PPH. This variation could not be explained by maternal characteristics, pregnancy characteristics, medical interventions or health care setting. Regional variation is either unavoidable or subsequent to regional variation of a yet unregistered variable

Prognostic models for stillbirth and neonatal death in very preterm birth: A validation study

OBJECTIVES: To validate externally 2 prognostic models for stillbirth and neonatal death in very preterm infants who are either known to be alive at the onset of labor or admitted for neonatal intensive care. PATIENTS AND METHODS: All infants, with gestational age 22 to 32 weeks, of European ethnicity, known to be alive at the onset of labor (n = 17 582) and admitted for neonatal intensive care (n = 11 578), who were born in the Netherlands between January 1, 2000, and December 31, 2007. The main outcome measures were stillbirth or death within 28 days for infants known to be alive at the onset of labor and death before discharge from the NICU for infants admitted for intensive care. Model performance was studied with calibration plots and c statistic. RESULTS: Of the infants known to be alive at the onset of labor, 16.7% (n = 2939) died during labor or within 28 days of birth, and 7.8% (n = 908) of the infants admitted for neonatal intensive care died before discharge from intensive care. The prognostic model for infants known to be alive at the onset of labor showed good calibration and excellent discrimination (c statistic 0.92). The prognostic model for infants admitted for neonatal intensive care showed good calibration and good discrimination (c statistic 0.82). CONCLUSIONS: The 2 prognostic models for stillbirth and neonatal death in very preterm Dutch infants showed good performance, suggesting their use in clinical practice in the Netherlands and possibly other Western countries. Copyrigh