Proving the cause of newborn neurologic injury in birth trauma litigation, an essential step to a successful lawsuit, is both complex and challenging. Determining causation begins with the newborn’s brain. The areas of the brain affected, the pattern of brain injury and the evolution of injury all provide vital information about the mechanism of injury and the timing of injury. Early neuroimaging can distinguish between chronic injury and acute injury, thereby establishing a window of opportunity for harm. Once that window has been defined, the timing of injury can be further refined through the obstetrical and neonatal clinical data.2 Events occurring during the narrowed window of opportunity can then be considered for contribution to injury and, applying the differential diagnosis, the most likely cause can be determined with confidence.
While there is still much that is not understood about the precise way acute neurologic injury occurs in newborns, modern neuroimaging techniques allow the detection of lesions occurring at or near the time of birth. The pathway to injury, in some scenarios, may be difficult to describe, but the time at which injury occurs is often far clearer. Proof of timing does not rely on a single test or clinical variable, but rather the evaluation of all the antenatal, peripartum and neonatal data. In my view, where the weight of evidence supports a particular cause and timing for neonatal neurologic injury, any outlying variables must be considered either non-essential or possibly spurious.
Neuroimaging, done at the appropriate time, can rule out antenatal causes, proving newborn neurologic injury occurred at or near the time of birth. Neuroimaging reveals patterns of injury and the involved areas of the brain, vital clues to the mechanism of injury. When used in combination with obstetrical and neonatal clinical data, the likely time of injury can be reasonably narrowed sufficiently to prove causation on a balance of probabilities. One must not be discouraged by assertions that neuroimaging is imprecise, allowing timing of injury to be determined only within days rather than hours3, as the timing of injury can be refined using the obstetrical and neonatal data. Judicious application of the differential diagnosis will often provide clear or probable evidence of cause and timing.
The pattern of brain injury provides clues regarding the mechanism of injury, and, therefore, the events that may have caused or contributed to the injury. Brain injury may be found on one or both sides of the brain in a diffuse pattern, or there may be focal lesions on one or both sides of the brain. Regardless of the topography of brain injury, in the setting of acute brain lesions of any description, the search for the likely cause is limited to a finite period of time where clinical events are closely monitored.4 Even where antenatal or genetic factors might be contributory in some fashion, the search must be for the peripartum events occurring within the window of opportunity that triggered the injury.
Much of the medical literature on newborn neurologic injury occurring at or around the time of birth is concerned with hypoxia-ischemia (asphyxia) and describes topography of brain injury that is mostly diffuse and bilateral. This asphyxial model of injury can be due to intermittent repetitive interruptions in fetal oxygenation, called “prolonged partial hypoxia-ischemia”, or more profound interference with fetal oxygenation, called “total or near total hypoxia-ischemia”. I will use the term “asphyxia” in place of “hypoxia-ischemia”. Asphyxia has been associated in the medical literature with a metabolic acidosis in cord blood, but both ischemia and hypoxia occur without a metabolic acidosis.
Certainly, with regard to prolonged partial asphyxia, and often with near total asphyxia, the brain damaging ischemia is preceded by periods of hypoxia leading to a building fetal metabolic acidosis and, ultimately, fetal hypotension. Hypotension reduces perfusion of blood to the brain globally, explaining the diffuse and bilateral topography of brain lesions with this mechanism of injury. Recently, some medical literature has paid more attention to acute newborn neurologic injury that is focal, resulting in injury to a defined area of the brain affected by the distribution of a particular cerebral blood vessel. These injuries are stroke, and may or may not be accompanied by a metabolic acidosis or fetal hypotension. For these injuries, there is a reduction in perfusion (ischemia) in a particular region or regions of the brain. It is beyond controversy that asphyxial injury can be caused by the mismanagement of care during labour and delivery (“intrapartum”). This paper will explore issues concerned with asphyxial injury as well as whether stroke may be preventable, in some cases, by better management of intrapartum care. Importantly, stroke can also “occur” with asphyxia.
This paper will be concerned primarily with ischemic newborn brain injury, both diffuse and focal, that might be attributed to mismanagement of labour and delivery. I contend that the conventional thinking of how and why newborn neurologic injury occurs is evolving, but too slowly. The prominence of intrapartum events as a cause for newborn neurologic injury must be acknowledged if morbidity is to be reduced. Safe obstetrical care demands an appreciation for the intrapartum antecedents to newborn neurologic injury.
Incidentally, the search for the cause of newborn neurologic injury is not important exclusively, or even primarily, for the purposes of accountability or litigation. Indeed, the main purpose of identifying the cause of these injuries should be the improvement of obstetrical care and the prevention of future injuries. Reducing harm should undoubtedly be the priority, although I am not convinced that there is sufficient attention paid to this objective in some corners of the medical community, with some members of that community overly preoccupied with resisting litigation. At times I wonder if there is not a conspiracy of silence or willful ignorance. Preventable injuries should reasonably result in both compensation for those wronged and lessons learned for care providers. The fact that some birth trauma lawsuits are successful against physicians and hospitals is not an argument for tort reform, but rather an argument for improving care and reducing morbidity. Only negligent care results in the imposition of liability. A better understanding of causation can reduce substandard care through recognition of potentially harmful fetal stress. Reduce substandard care and fewer lawsuits will inevitably follow.
Read full paper in PDF format: Birth Trauma Litigation: Proving the Cause of Newborn Neurologic Injury