ABP Pediatric Critical Care Medicine key terms

The change in lung volume produced by a given change in distending pressure, expressed in milliliters per centimeter of water. Low compliance means the lungs or chest wall feel stiff and need higher pressure to fill.

The portion of each breath that fills airways and alveoli but never reaches pulmonary capillary blood, so it takes no part in gas exchange. It is normally about a third of tidal volume and rises in lung disease.

Trapped gas that creates positive pressure in the alveoli at the end of exhalation, when the patient has not had time to breathe out fully. It raises the work of breathing and can drop blood pressure during mechanical ventilation.

Blood that moves from the right side of the heart to the left without picking up oxygen in ventilated alveoli. Shunt lowers arterial oxygen content and does not correct much when extra oxygen is given.

The airway pressure measured during a brief pause at the end of inspiration, reflecting the pressure that stretches the alveoli. It is used to estimate the risk of ventilator-induced lung injury and is kept below about 28 to 30 centimeters of water.

An acute, diffuse inflammatory lung injury in children meeting timing, imaging, oxygenation, and ventilation criteria, with edema not fully explained by heart failure. It causes severe hypoxemia and stiff lungs and often requires mechanical ventilation and sometimes extracorporeal support.

The volume of blood the heart ejects each minute, equal to stroke volume multiplied by heart rate. It is the main determinant of oxygen delivery to tissues and is indexed to body surface area in children.

The principle that stretching the heart muscle with more filling volume increases the force of contraction, up to a point. Beyond that point, extra fluid raises filling pressures without adding stroke volume.

The resistance that blood vessels throughout the body offer to flow, calculated from the pressure drop across the circulation divided by cardiac output. High resistance means cold, poorly perfused extremities; low resistance means warm, bounding pulses.

A shock state in which low cardiac output and very high vascular resistance dominate, so the child looks mottled with cool limbs, weak pulses, and prolonged capillary refill. Treatment emphasizes fluids and drugs that increase contractility rather than pure vasoconstrictors.

Septic shock that persists after at least 40 to 60 milliliters per kilogram of isotonic fluid has been given in the first hour, so a vasoactive drug infusion is needed to restore perfusion pressure while signs of fluid overload are watched for.

A life-threatening response to infection causing organ dysfunction, recognized in children by abnormalities in mental status, perfusion, respiratory function, or laboratory values, together with suspected or proven infection.

The percentage fall in blood lactate over time after resuscitation begins. Rising or persistently high lactate suggests ongoing tissue hypoperfusion, while successful clearance indicates that oxygen delivery has improved.

Fever in a child whose absolute neutrophil count is very low, usually below 500 cells per microliter, a state that can progress rapidly to overwhelming bacterial sepsis and requires prompt empiric antibiotics.

A severe hyperinflammatory syndrome with uncontrolled immune activation, marked by prolonged fever, low blood counts, liver and spleen enlargement, high ferritin, and low fibrinogen, which can mimic and accompany sepsis.

Procedures that remove or drain the focus of infection, such as abscess drainage, debridement of infected tissue, or removal of an infected catheter, without which antibiotics alone often fail.

The pressure inside the rigid skull created by brain tissue, blood, and cerebrospinal fluid. Because the skull cannot expand, any added volume raises pressure and can reduce blood flow to the brain.

The difference between mean arterial pressure and intracranial pressure, representing the driving force for blood flow to the brain. It is monitored after severe traumatic brain injury to keep the brain adequately perfused.

A seizure lasting more than five minutes, or two or more seizures without return to baseline between them, treated as a medical emergency with staged anticonvulsant dosing and a search for the underlying cause.

Treatment with hypertonic saline or mannitol that draws water out of brain tissue across the blood-brain barrier, lowering intracranial pressure. It is given in boluses and requires close monitoring of sodium and kidney function.

The irreversible loss of all brain function, including the brainstem, in a child who has a known cause, is in a coma, has no brainstem reflexes, and cannot breathe spontaneously, confirmed by protocolized testing.

A strategy for major trauma that prioritizes stopping bleeding and restoring circulating volume and clotting, using blood products over crystalloid, permissive hypotension, and early surgery rather than a long preoperative workup.

Organ dysfunction caused by sustained high pressure inside the abdomen, usually above 20 millimeters of mercury with new organ failure, often recognized by distension, high airway pressures, and falling urine output.

A weight-based estimate of fluid needs in the first 24 hours after a major burn, using 4 milliliters per kilogram per percent of body surface burned, with half given in the first 8 hours.

A coordinated, preplanned approach that rapidly delivers balanced blood components in roughly equal ratios to a child with massive hemorrhage, while limiting crystalloid and monitoring calcium, temperature, and clotting.

Air trapped in the pleural space under pressure that shifts mediastinal structures and blocks venous return, causing sudden respiratory distress, hypoxemia, and hypotension; it needs immediate needle or finger decompression.

An abrupt fall in kidney function, defined by a rising serum creatinine or falling urine output over hours to days, reflecting reduced filtration or tubular injury rather than chronic kidney disease.

A slow, gentle method of removing fluid and solutes from the blood through a filter over many hours, better tolerated by hemodynamically unstable children than conventional intermittent hemodialysis.

A metabolic emergency of insulin deficiency causing high blood sugar, ketones, and acid, requiring careful fluid and insulin administration and close monitoring for cerebral edema during treatment in children.

Inadequate cortisol activity relative to the stress of severe illness, suspected in shock that still needs vasopressors despite adequate fluids, and sometimes treated with hydrocortisone after sampling cortisol levels.

Metabolic disturbances, including low phosphate, potassium, and magnesium, that occur when a malnourished child is fed too quickly, requiring slow caloric advancement and electrolyte replacement.

Preparing the child, giving an induction agent and a neuromuscular blocker in quick succession, and placing a breathing tube while an assistant applies airway pressure to reduce the risk of aspiration.

Placing a needle into the marrow cavity of a long bone to give fluids and drugs when intravenous access cannot be obtained quickly; it works within seconds and serves as a temporary emergency route.

Continuous measurement and display of exhaled carbon dioxide. It confirms tracheal tube position, detects disconnection or obstruction, and gives an early warning of falling cardiac output.

Deliberately holding the body temperature at a chosen level, usually mild hypothermia, for hours to days after a neurological insult or cardiac arrest, with careful control of shivering and rewarming.

Agreement from a child old enough to understand, sought alongside parental permission before procedures, using language matched to the child's development; refusal is taken seriously even when it is not legally binding.

A clinical judgment that a proposed intervention cannot achieve the goal it is intended to achieve, such as restoring a meaningful life, and therefore should not be offered or continued.

Bedside rounds that include the family as partners, explaining the plan and inviting questions, while protecting confidentiality and keeping teaching and sensitive discussion appropriately private.

A workplace approach that treats human error as a system problem while still holding people accountable for reckless behavior, encouraging staff to report mistakes and safety concerns without fear.