A clinician relies too heavily on “the fifth vital sign.”
Inadequate Management of Wheezing, Coughing Infant
A six-week-old infant was brought to a Mississippi hospital emergency department (ED) at about 10:30 PM with signs of wheezing, coughing, and decreased playfulness. Thirty minutes later, he was evaluated by the emergency physician. Initial test results included an oxygen saturation (SaO2) level of 100%, but she suspected pneumonia and ordered further tests.
The child underwent a breathing treatment, and his condition appeared to be improving. About 45 minutes after his initial evaluation, while being transported for a chest x-ray, he experienced cardiorespiratory arrest. Resuscitation was unsuccessful.
The plaintiff claimed that the emergency physician should have consulted a pediatrician, conducted continuous electronic monitoring of the infant, and administered oxygen.
The defendant claimed that the infant was properly monitored and that oxygen was not required, since his oxygen saturation level was 100%. Additionally, the defendant claimed she was cross-trained as a pediatrician and that the outcome would have been the same, regardless of treatment, because the child had advanced, severe pneumonia.
According to a published account, a defense verdict was returned for the defendant emergency physician. Claims involving the defendant hospital were subject to decision by the court, which was also a defense verdict.
This case illustrates the potential pitfalls of relying too heavily on any one diagnostic element. In this case, there was an arguable overreliance on pulse oximetry values to exclude a clinically significant respiratory condition.
Diagnosing pneumonia can be difficult, and the clinical gestalt must be considered. A low pulse oximetry reading itself should be concerning, whereas normal pulse oximetry itself should not be reassuring when the patient exhibits tachypnea or other signs of distress. In one study, pulse oximetry was studied to determine whether it could be used to exclude pneumonia in children younger than 2 years presenting with respiratory complaints. It could not.1 In sum, SaO2 levels may be normal in patients with pathology, and while initially reassuring, may plummet after the patient tires.
In this case, the defendants prevailed. The case report does not provide the patient’s vital signs, but the use of bronchodilators and the x-ray order suggest that there was some degree of respiratory distress. Because the child experienced cardiorespiratory arrest after one hour and 15 minutes in the ED, the defense was likely able to convince the jury that this unfortunate infant faced a high mortality risk even with more aggressive treatment.
Some have called pulse oximetry the “fifth vital sign.” Don’t let it become the only one. The SaO2 must be interpreted in the context of the patient’s overall presentation and in view of the other vitals (especially respiratory rate). —DML
Cases reprinted with permission from Medical Malpractice Verdicts, Settlements and Experts, Lewis Laska, Editor, (800) 298-6288.
1. Tanen DA, Trocinski DR. The use of pulse oximetry to exclude pneumonia in children. Am J Emerg Med. 2002;20(6):521-523.