What arterial blood gas result is expected in a person experiencing a panic attack?

Choice A rationale

Infants have a much higher body surface area to volume ratio compared to adults. This physiological characteristic means that a larger proportion of their total body water is in contact with the environment, allowing for rapid fluid loss through the skin via evaporation. Because infants have more skin surface relative to their small body mass, even minor increases in environmental temperature or respiratory rate can lead to significant fluid deficits, making them scientifically more prone to rapid dehydration.

Choice B rationale

Subcutaneous fat actually serves as an insulating layer and does not increase the risk of dehydration. In fact, adipose tissue has a lower water content than muscle tissue, but its presence does not predispose an infant to fluid loss. Infants typically have a higher percentage of total body water, approximately 75 percent, compared to adults. The risk of dehydration is related to how that water is distributed and lost, not the amount of subcutaneous fat present on the infant's body.

Choice C rationale

Forgetfulness regarding fluid intake is a behavioral risk factor often associated with the elderly or older children, but it is not applicable to infants. Infants rely entirely on caregivers for fluid administration and cannot consciously choose or forget to drink. Their risk for dehydration is primarily driven by physiological and anatomical factors, such as their high metabolic rate and immature renal function, which limit their ability to concentrate urine and conserve water when fluid intake is insufficient.

Choice D rationale

The sweat mechanism in infants is actually immature and less efficient than in adults. Infants do not sweat as effectively to dissipate heat, which puts them at a higher risk for overheating rather than dehydration specifically through sweating. While they do lose fluid through the skin, the primary issue is the high surface area to volume ratio and a higher respiratory rate, which increases insensible water loss, rather than an overactive or increased sweat mechanism compared to older individuals.

Choice A rationale

Metabolic alkalosis occurs when the pH is above 7.45 and the bicarbonate level is above 26 mEq/L. This condition is typically caused by a loss of hydrogen ions or an excess of bicarbonate. In this clinical scenario, the pH is 7.30 and the bicarbonate is 24 mEq/L, which is within the normal range of 22 to 28 mEq/L. Therefore, the imbalance cannot be classified as metabolic alkalosis based on these laboratory values.

Choice B rationale

Respiratory acidosis is characterized by a pH below 7.35 and a PaCO2 above 45 mmHg. The normal range for pH is 7.35 to 7.45, and for PaCO2 is 35 to 45 mmHg. In this case, the pH of 7.30 indicates acidemia, and the elevated PaCO2 of 50 mmHg identifies the respiratory system as the cause. The normal bicarbonate level suggests that renal compensation has not yet occurred, confirming an acute respiratory acid-base imbalance.

Choice C rationale

Respiratory alkalosis involves a pH greater than 7.45 and a PaCO2 less than 35 mmHg. This state is generally caused by hyperventilation, which leads to the excessive elimination of carbon dioxide from the lungs. Since the patient in this scenario has a low pH of 7.30 and a high carbon dioxide level of 50 mmHg, the laboratory data is the direct opposite of what is required for a diagnosis of respiratory alkalosis.

Choice D rationale

Metabolic acidosis is defined by a pH below 7.35 and a bicarbonate level below 22 mEq/L. While the pH of 7.30 in this scenario indicates acidosis, the bicarbonate level of 24 mEq/L is perfectly within the standard reference range of 22 to 28 mEq/L. Because the primary abnormality is found in the PaCO2 level rather than the bicarbonate level, the source of the acid-base disturbance is respiratory and not metabolic in origin.