Shock is a state of circulatory dysfunction that causes inadequate oxygen delivery to tissues. If left untreated, the mismatch in metabolic demand and supply of oxygen will cause organ damage and eventually death.
To guide neonatologists, pediatricians, advanced practitioners, and nurses on the management of shock in the neonatal period.
In the neonate, multiple factors can cause shock, such as myocardial dysfunction, sepsis, abnormal peripheral vasoregulation, hypovolemia, loss of vascular integrity, and adrenal insufficiency. The diagnosis of shock is based on indicators of inadequate perfusion such as tachycardia, respiratory distress (e.g., tachypnea, grunting, or retractions), temperature instability, delayed capillary refill time, cool extremities, poor color, oliguria, poor feeding or impaired feeding tolerance, low tone, and metabolic acidosis.
There are three phases of shock: compensated, uncompensated, and irreversible shock. During compensated shock, vital organ function is maintained by preserving blood flow to the heart, brain, and adrenal glands at the expense of the other organs such as the skin, kidneys and GI tract. During this phase, blood pressure (BP) is usually normal or near normal. Infants will likely have tachycardia, low urine output, increased respiratory rate, and delayed capillary refill time. If untreated or inadequately treated, the neonate’s shock will progress to the uncompensated phase where compensatory mechanisms are no longer adequate to maintain perfusion to the vital organs. Decreased tissue and organ perfusion results in reduced oxygen delivery and subsequent anaerobic metabolism and production of lactic acid. Organ dysfunction may manifest as decreased myocardial contractility, kidney failure, liver failure, acute respiratory distress syndrome, pulmonary edema, pulmonary hypertension, adrenal insufficiency, capillary leak, or encephalopathy. The next step in rapidly progressing or untreated shock is an irreversible shock, with cellular damage and complete organ failure resulting in death.
Clinicians should initiate treatment when there is evidence of systemic hypoperfusion (see above), even if the BP is in the normal range. General recommendations for management of neonatal shock are:
Assess respiratory function (airway and breathing) to assure adequate oxygen delivery. Infants may benefit from increased respiratory support and early intubation if apnea, increased work of breathing, or hypoxemia is present.
Assure adequate vascular access at the first signs of shock with venous access (preferably two sites) for the administration of fluids and medications.
Consider obtaining arterial access for continuous BP monitoring.
Carefully monitor blood pressure, perfusion, and urine output.
In addition to treating the underlying cause, provide supportive care such as maintenance of normothermia, avoidance of hypoglycemia, and correction of electrolyte abnormalities.
Note that the use of sodium bicarbonate boluses to treat metabolic acidosis in neonates is controversial. Use of sodium bicarbonate as a bolus has not been shown to improve outcomes and may cause harm such as transient cardiac dysfunction.