Chapter 94 Ph Probe Monitoring
The presence of acid reflux in the distal esophagus is detected by pH probe monitoring. A thin, flexible probe is inserted transnasally and advanced to the distal esophagus 1 to 4 cm above the lower esophageal sphincter. It is attached to a portable recording device that permits monitoring of infants and children in a physiologic setting with normal dietary intake. Usually, the physician or practitioner will use a diary to record physical events that may suggest reflux activities such as coughing, gagging, hiccupping, burping, abdominal “soreness” or pain, “sour taste” in the mouth; and, for small infants, episodes or presence of arching and irritability, cyanosis, bradycardia, and apnea. This diary is used to compare the computer reading to the child’s activities. The test runs for approximately 18 to 24 hours. Occasionally, older children are permitted to go home with the tube in place. Maneuvers that increase intraabdominal pressure such as bending over or exercise may increase episodes of reflux. There is an initial increase in bicarbonate-containing saliva following placement of a nasogastric tube, which can cause gastroesophageal reflux (GER) to be underestimated.
The physician or practitioner may consider repeating a negative pH probe in patients with symptoms of GER, especially if the duration of the study was less than 24 hours. A negative pH probe in a symptomatic child does not entirely eliminate the diagnosis of reflux. However, it has a very high specificity, so a positive result confirms the diagnosis of GER.
NURSING INTERVENTIONS
1. Explain procedure to child and parents before it is performed.
2. Probe should be securely taped to infant’s or child’s face to maintain placement. Reinforce as needed to prevent dislodgement or removal by infant or child.
3. Instruct parents to document starting and ending time of feedings, position changes, vomiting, apnea, and so on. Careful documentation is necessary to ensure accurate results.
4. Instruct family and/or parents to avoid placing tension on probe or electrode wire.
5. Normal pH is 5.5 to 7.0; pH readings on meter that are higher than 8 or that are negative number indicate machine malfunction.
Hay WW, et al. Current pediatric diagnosis and treatment, ed 17. New York: McGraw-Hill, 2005.
Perlstein PH, et al. Implementing an evidence-based acute gastroenteritis guideline at a children’s hospital. Jt Comm J Qual Improv. 2002;28(1):20.
Wong DL, et al. Maternal child nursing care, ed 3. St. Louis: Mosby, 2006.
