Management of neonatal neurologic injury evidence-based outcomes anesthesia key nanoxia ncore

Neonatal encephalopathy is a relatively common condition. Nelson and leviton define it as a clinical syndrome of “disturbed neurologic function in the earliest days of life in the term infant, manifested by difficulty with initiating and maintaining respiration, depression of tone and reflexes, subnormal level of consciousness, and often by seizures” ( 1). Kurinczuk et al. Recently analyzed data on incidence and estimated it to be 3/1,000 live births, with a 95% confidence interval (CI) 2.7 to 3.3 ( 2), with earlier studies placing it between 2 and 6/1,000 live births ( 1). Neonatal encephalopathy was considered to be the result of an intrapartum event, and different terms were used to define the process: hypoxic–ischemic encephalopathy, birth asphyxia, postasphyxial encephalopathy, and perinatal asphyxia.Nanoxia ncore


in modern thinking, neonatal encephalopathy describes a set of clinical symptoms without assumptions of either etiology or pathogenesis. Hypoxic–ischemic encephalopathy is a subgroup of neonatal encephalopathy, where there is evidence of a recent, usually intrapartum, ischemic event. A recent meta-analysis estimated the incidence of hypoxic–ischemic encephalopathy to be 1.5/1,000 live births (95% CI, 1.3 to 1.7) ( 2), with previous reports ranging from 1 to 8/1,000 live births.

Table 17-1 management of infants with hypoxic-ischemic encephalopathy

Identification

• evidence of a sentinel event during labor, e.G., fetal heart rate abnormality

• severely depressed infant (low-extended apgar score)

• need for resuscitation in the delivery room

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• evidence of severe fetal acidemia

• early abnormal neurologic examination (neonatal encephalopathy) and/or abnormal assessment of cerebral function (amplitude-integrated electroencephalogram)

• amplitude-integrated electroencephalography, head ultrasound, computer tomography, and magnetic resonance imaging can be used to assess the severity and the progression of hypoxic–ischemic encephalopathy ( 15, 16, 17, 18).

Supportive care

• maintain adequate ventilation

• avoid hypotension

• avoid hypoglycemia. A retrospective review of 185 infants admitted to NICU with acidosis suggests that initial hypoglycemia (BG 40 mg/dl) is an important predictive factor for perinatal brain injury ( 19), and may accentuate brain damage ( 20).Nanoxia ncore

• treat seizures. Hypoxic–ischemic cerebral injury is the most common cause of early onset neonatal seizures ( 6). Seizure activity may contribute to ongoing injury: repetitive seizures disturb the brain growth and development as well as increase the risk for subsequent epilepsy ( 21, 22).

Interventions against the ongoing brain injury

• cooling

• oxygen-free radical inhibitors and scavengers

• excitatory amino acids antagonists

• growth factors

• prevention of nitric oxide formation

• blockage of apoptotic pathways

The third large study—the TOBY trial ( 36) enrolled 325 infants with moderate to severe hypoxic–ischemic encephalopathy at 42 centers worldwide. The intervention was whole body cooling. Gel packs were used to initiate hypothermia, and cooling blankets were used to maintain the temperature at 33°C to 34°C for 72 hours.Nanoxia ncore unfavorable outcomes were present in 53% of controls and 45% of cooled infants (RR 0.86, 95% CI, 0.68 to 1.07). The difference in primary outcome (death or moderate to severe disability) did not reach statistical significance, but among survivors, infants in the cooled group had increased rate of survival without neurologic abnormality (44% in the cooled group vs. 28% in the standard treatment group, RR 1.57, 95% CI, 1.16 to 2.12, p = 0.003). Also the intervention reduced the risk of cerebral palsy among survivals (RR 0.67, 95% CI, 0.47 to 0.96, p = 0.03), improved scores on the mental developmental index and psychomotor index of the bayley scales of infant development II ( p = 0.03 for each) and the gross motor classification system ( p = 0.01).Nanoxia ncore the study concluded that the induction of moderate hypothermia for 72 hours in infants with perinatal asphyxia did not significantly reduce the combined rate of death or severe disability but resulted in improved neurologic outcomes in survivors ( 36).