Diagnostic Ionizing Radiation Exposure in Premature Patients
Diagnostic Ionizing Radiation Exposure in Premature Patients
We included 215 premature infants in this study with gestational age 29.2±2.3 weeks (mean±standard deviation) and birth weight 1262±433 g. There were 15.0±15.0 X-ray examinations per infant, of which 4.4±2.9 were obtained for evaluation of CVL placement, 5.7±9.9 for GI indications and 5.3±9.3 for respiratory indications. There were 4.5±4.3 babygrams obtained per patient that included gonadal exposure in all females and most males. Only one infant received no X-rays and four infants (1.8%) had one X-ray. In all, 59 infants (27.4%) had 5 to 9 X-rays, 34 infants (15.8%) had 10 to 14 X-rays, 27 infants (12.5%) had 15 to 19 X-rays and 15 infants (7.0%) had 30 to 39 X-rays. Three infants (1.4%) had greater than 70 X-rays. The range was 0 to 89 X-rays for all patients (Figure 1).
(Enlarge Image)
Figure 1.
Total number of X-ray and fluoroscopic studies per patient for infants <33 weeks gestational age.
The most common X-ray procedure ordered in the NICU was the portable babygram (chest X-ray and abdominal X-ray). Due to the fragile nature of premature infants, portable X-ray units were brought to the NICU instead of requiring that these infants travel to the radiology department.
Eleven infants (5.1%) who received CVL placement in the NICU were exposed to an estimated ionizing radiation dose greater than the recommended maximum of 1000 μSv (range 1010 to 4200 μSv). Infants who received >2000 μSv were noted to have had one or more CT scans performed during their NICU stay. Six infants (3.3%) in our study had at least one CT scan and four infants (1.8%) had more than one CT scan. Two infants (0.9%) received CT scans resulting in an effective dose greater than 1000 μSv. One of these infants had a birth weight of <750 g, at 24.6 weeks gestational age. This infant was mechanically ventilated, required a total of six CVLs, was monitored for necrotizing enterocolitis, and received a total of 67 X-ray examinations. The remaining infants whose estimated radiation dose was above 1000 μSv were found to have been mechanically ventilated and suffered from either necrotizing enterocolitis or respiratory distress syndrome, requiring multiple X-ray examinations and follow-up studies. We found that 5.1 and 6.5% of infants had a cumulative effective dose of 900 and 800 μSv, respectively.
Six percent of infants in this study had one or more fluoroscopic procedures performed. Adding the effective doses from the fluoroscopic procedures to the radiographic and CT effective doses resulted in 12.1% of the infants in this study receiving more than the recommended 1000 μSv radiation dose during their NICU stay (Table 4). Infants with a birth weight of <750 g were found to have received the highest effective radiation dose (650±650 μSv) when compared with other birth weight categories (Table 5). While low birth weight is associated with increased morbidity, only one infant in this category received more than the recommended maximum of 1000 μSv during their NICU stay.
There were 399 CVLs placed during the study period, of which 95.9% (n=382) required at least one X-ray to document placement. Of the 399 CVLs that were placed, the most common were the peripherally inserted central venous catheter (PICC) (45.1%) and UVC (51.1%). An average of 2.37±1.47 X-rays were used to evaluate the PICC placement (80 μSv), 1.95±1.19 X-rays for UVC placement (50 μSv), 2.8±1.5 X-rays for UVC/umbilical arterial catheter combination (60 μSv) and 1.07±0.47 X-rays for femoral venous catheter placement (20 μSv). Femoral venous catheters were placed only after multiple unsuccessful attempts to place a PICC, or if there were contraindications for PICC placement. There were 2.2±1.2 CVLs placed per infant; 200 infants (93%) had an UVC, and 149 infants (69%) had a PICC placed. We found that 56.0% of the CVLs required more than one babygram to determine placement and 20.9% required more than one chest X-ray to determine placement. There were 2.8±2.0 babygrams (70 μSv) and 1.56±1.99 chest X-rays for CVL placement. Overall, an average of 4.38±2.91 of the total X-rays obtained during a premature infant's NICU stay were related to placement of CVLs. The overall effective radiation dose due to CVL placement was 65.67±86.3 μSv, noting that this large standard deviation is indicative of a large variation in dose among NICU infants.
There were an average of 5.7±9.9 X-rays obtained to evaluate GI problems. All fluoroscopic procedures were ordered for GI indications. The average effective radiation dose due to GI indications was 140.5±430.5 μSV with a range of 0 to 4245 μSv. GI indications accounted for 12 (46.2%) of the infants who received more than the recommended maximum of 1000 μSv. We found that an average of 5.25±9.34 X-rays were obtained due to respiratory indications. The average cumulative radiation exposure due to the X-rays obtained for respiratory indications was 62.0±77.60 μSv.
Results
We included 215 premature infants in this study with gestational age 29.2±2.3 weeks (mean±standard deviation) and birth weight 1262±433 g. There were 15.0±15.0 X-ray examinations per infant, of which 4.4±2.9 were obtained for evaluation of CVL placement, 5.7±9.9 for GI indications and 5.3±9.3 for respiratory indications. There were 4.5±4.3 babygrams obtained per patient that included gonadal exposure in all females and most males. Only one infant received no X-rays and four infants (1.8%) had one X-ray. In all, 59 infants (27.4%) had 5 to 9 X-rays, 34 infants (15.8%) had 10 to 14 X-rays, 27 infants (12.5%) had 15 to 19 X-rays and 15 infants (7.0%) had 30 to 39 X-rays. Three infants (1.4%) had greater than 70 X-rays. The range was 0 to 89 X-rays for all patients (Figure 1).
(Enlarge Image)
Figure 1.
Total number of X-ray and fluoroscopic studies per patient for infants <33 weeks gestational age.
The most common X-ray procedure ordered in the NICU was the portable babygram (chest X-ray and abdominal X-ray). Due to the fragile nature of premature infants, portable X-ray units were brought to the NICU instead of requiring that these infants travel to the radiology department.
Eleven infants (5.1%) who received CVL placement in the NICU were exposed to an estimated ionizing radiation dose greater than the recommended maximum of 1000 μSv (range 1010 to 4200 μSv). Infants who received >2000 μSv were noted to have had one or more CT scans performed during their NICU stay. Six infants (3.3%) in our study had at least one CT scan and four infants (1.8%) had more than one CT scan. Two infants (0.9%) received CT scans resulting in an effective dose greater than 1000 μSv. One of these infants had a birth weight of <750 g, at 24.6 weeks gestational age. This infant was mechanically ventilated, required a total of six CVLs, was monitored for necrotizing enterocolitis, and received a total of 67 X-ray examinations. The remaining infants whose estimated radiation dose was above 1000 μSv were found to have been mechanically ventilated and suffered from either necrotizing enterocolitis or respiratory distress syndrome, requiring multiple X-ray examinations and follow-up studies. We found that 5.1 and 6.5% of infants had a cumulative effective dose of 900 and 800 μSv, respectively.
Six percent of infants in this study had one or more fluoroscopic procedures performed. Adding the effective doses from the fluoroscopic procedures to the radiographic and CT effective doses resulted in 12.1% of the infants in this study receiving more than the recommended 1000 μSv radiation dose during their NICU stay (Table 4). Infants with a birth weight of <750 g were found to have received the highest effective radiation dose (650±650 μSv) when compared with other birth weight categories (Table 5). While low birth weight is associated with increased morbidity, only one infant in this category received more than the recommended maximum of 1000 μSv during their NICU stay.
Radiation for Central Line Placement
There were 399 CVLs placed during the study period, of which 95.9% (n=382) required at least one X-ray to document placement. Of the 399 CVLs that were placed, the most common were the peripherally inserted central venous catheter (PICC) (45.1%) and UVC (51.1%). An average of 2.37±1.47 X-rays were used to evaluate the PICC placement (80 μSv), 1.95±1.19 X-rays for UVC placement (50 μSv), 2.8±1.5 X-rays for UVC/umbilical arterial catheter combination (60 μSv) and 1.07±0.47 X-rays for femoral venous catheter placement (20 μSv). Femoral venous catheters were placed only after multiple unsuccessful attempts to place a PICC, or if there were contraindications for PICC placement. There were 2.2±1.2 CVLs placed per infant; 200 infants (93%) had an UVC, and 149 infants (69%) had a PICC placed. We found that 56.0% of the CVLs required more than one babygram to determine placement and 20.9% required more than one chest X-ray to determine placement. There were 2.8±2.0 babygrams (70 μSv) and 1.56±1.99 chest X-rays for CVL placement. Overall, an average of 4.38±2.91 of the total X-rays obtained during a premature infant's NICU stay were related to placement of CVLs. The overall effective radiation dose due to CVL placement was 65.67±86.3 μSv, noting that this large standard deviation is indicative of a large variation in dose among NICU infants.
Radiation Exposure Due to GI and Respiratory Indications
There were an average of 5.7±9.9 X-rays obtained to evaluate GI problems. All fluoroscopic procedures were ordered for GI indications. The average effective radiation dose due to GI indications was 140.5±430.5 μSV with a range of 0 to 4245 μSv. GI indications accounted for 12 (46.2%) of the infants who received more than the recommended maximum of 1000 μSv. We found that an average of 5.25±9.34 X-rays were obtained due to respiratory indications. The average cumulative radiation exposure due to the X-rays obtained for respiratory indications was 62.0±77.60 μSv.
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