A diagnostic error is defined as “a failure to establish an accurate and timely explanation
for a patient's health problem.”[1] Such errors cause significant harm to patients, and were identified as a priority
by the National Academy of Medicine in its 2015 report, Improving Diagnosis in Health Care. However, diagnostic errors remain largely unappreciated within the quality and patient
safety movement in health care.[2]
[3] In particular, diagnostic errors within a neonatal intensive care unit (NICU) are
understudied.[2] NICU patients are fragile and often require multiple invasive interventions in a
fast-paced, complex environment. As a result, they are at high risk of diagnostic
errors that result in significant short-term and long-term health consequences.[4] To date, however, the few studies on diagnostic errors in the NICU have been autopsy-based
evaluations that did not assess nonlethal diagnostic errors.[4]
[5]
In this case series, we present 10 examples of diagnostic errors which occurred in
the NICU at this institution. These cases were identified by us during the course
of our clinical work over a period of 9 months. We classify the errors by the component
of the diagnostic process which led to the error in diagnosis: missed physical exam
findings, misinterpreted vital signs, incorrectly interpreted radiographic imaging,
delayed laboratory result interpretation, incorrectly interpreted echocardiographic
imaging, inadequate team communication, and no fault. These cases serve as prototypical
examples of diagnostic errors in the NICU, and highlight the need for further research
in this field.
Cases
Missed Physical Examination Findings
Case 1
A 31-week gestation infant was born by spontaneous vaginal delivery (SVD) after preterm
labor and prolonged (1 week) preterm premature rupture of membranes. The mother had
received regular prenatal care, had negative results on prenatal tests for infections,
and denied any history of herpes simplex virus (HSV) infection. On admission, the
eyes were clear without discharge, with a bilateral red reflex. The patient had an
uncomplicated NICU course until 5 weeks of age, when the infant developed eye redness
and eyelid swelling of the right eye. Examination by an ophthalmologist revealed a
geographic ulcer with central large epithelial defect that was suggestive of HSV keratitis.
No eye exam had been documented in the daily progress notes in the week prior to the
ophthalmology review. A viral culture of the eye discharge yielded HSV type 2. Blood
and cerebral spinal fluid (CSF) cultures were negative for HSV and other infections.
The patient received a 21-day treatment course of intravenous acyclovir as well as
topical ganciclovir, then was switched to PO acyclovir only for suppressive therapy.
The patient has now been discharged from the NICU, and remains on PO acyclovir at
home, which is being managed by the infectious disease outpatient team. The plan is
for 12 months of suppressive therapy with PO acyclovir. The patient is also being
followed in the ophthalmology clinic with slow improvement of the scarring from the
infection noted in the most recent clinic notes. The patient's long-term vision prognosis
remains unclear.
Case 2
A 40-week gestation infant was born by SVD after an uncomplicated pregnancy, then
admitted to the well-baby nursery, where the admitting pediatrician documented a normal
exam—including a patent and normally placed anal opening. Enteral feedings were then
started. At 10 hours of life, the patient developed emesis and a distended abdomen.
On reassessment, the infant was noted to have an imperforate anus. After transfer
to the NICU a membrane covering a perineal fistula was excised by the pediatric surgery
team at the bedside. Subsequently the patient fed well and passed stools normally.
Misinterpreted Vital Sign Findings
Case 3
A 37-week gestation infant was born by scheduled cesarean section (C-section) delivery.
Prenatally multiple fetal congenital anomalies were identified, and fetal magnetic
resonance imaging (MRI) demonstrated bilateral cerebral ventriculomegaly with mass
effect on the cerebellum, caudal regression spectrum, kyphosis, and scoliosis. A fetal
echocardiogram (echo) revealed a ventricular septal defect (VSD) and biventricular
hypertrophy. The cardiologist recommended an echo after delivery. On admission to
the NICU, the systolic blood pressure in the upper limb was documented to be higher
than that in the lower limb by 30 mm Hg. This result—a ‘red flag’ for aortic coarctation—was
recorded in the electronic medical record, but was not flagged as abnormal or communicated
by the bedside nurse to the neonatology clinician. Neither the neonatologist nor the
cardiologist recognized this concerning vital sign during their initial review of
the chart, and this abnormal result is not mentioned in any of the notes from the
day of admission. As the patient was otherwise hemodynamically stable after being
intubated, a postnatal echo was deferred until the following day, while imaging of
the head and kidneys was performed that night. Aortic coarctation was suspected on
an echo at 22 hours of life, and confirmed on computed tomography (CT) angiography
scan. The patient received a prostaglandin E1 infusion to maintain systemic perfusion
for several days, until the parents elected to redirect care due to the multiple other
congenital anomalies not consistent with long-term survival.
Incorrectly Interpreted Radiographic Imaging and Delayed Laboratory Result Interpretation
Case 4
A 34-week gestation infant was born by C-section, then admitted to the NICU for prematurity
and hypoglycemia. An umbilical venous catheter (UVC) could not be inserted, so a peripherally
inserted central catheter (PICC) was inserted into the right femoral vein. Afterward,
a radiograph of the chest and abdomen was obtained to confirm correct positioning
of the PICC. The radiology report described “a bubbly pattern in the descending colon,”
which was suggestive of pneumatosis. The pneumatosis was an incidental finding separate
from the PICC insertion procedure, the placement of which did not have any influence
on the development of the pneumatosis. There is a system in place at this institution
by which a radiologist directly communicates concerning findings on imaging to the
bedside clinician, but in this case it was not utilized by the radiologist who read
the radiograph, and the neonatologist remained unaware of pneumatosis or the comments
on the radiology report. As the radiograph had been obtained for PICC placement, and
the patient appeared clinically well, the neonatologist initiated enteral feeds. At
14 hours of life, a blood culture grew gram-negative rods (later identified as Escherichia coli). This was also not recognized by the on-call neonatologist for 6 hours. During this
period, the enteral feeds were continued, and no repeat blood cultures were sent until
20 hours of life, when the patient developed bloody stools. A repeat radiograph at
that time demonstrated diffuse pneumatosis consistent with necrotizing enterocolitis.
Feeds were then discontinued, and a full sepsis evaluation including a lumbar puncture
for CSF culture was performed. The infant was treated with antibiotics, required multiple
surgical interventions for colonic stricture, and experienced long-term feeding difficulties.
Incorrectly Interpreted Radiographic Imaging
Case 5
A 24-week gestation infant was born by SVD after preterm labor. At 2 weeks of life,
the patient developed abdominal distension. An abdominal radiograph was obtained to
evaluate for an etiology of the abdominal distension such as pneumoperitoneum or pneumatosis.
The radiograph demonstrated diffuse gaseous distension of the colon and small bowel,
and also noted a right pleural effusion. However, as this was an abdominal radiograph,
the lungs were not completely evaluated in this study. The radiology report indicates
that the finding of the pleural effusion was communicated to “the physician taking
care of the patient,” however, this was not noted in any of the documentation in the
electronic medical record. Additionally, a dedicated follow-up chest radiograph was
not obtained to fully evaluate the lungs. Instead the neonatology team focused on
the abdominal distension, as the patient became critically ill with significant metabolic
acidosis and decreased urine output concerning for an acutely evolving intraabdominal
pathology. The following day, however, the patient had an acute respiratory decompensation
with prolonged desaturations not responsive to manual positive pressure breaths or
increases in fraction of inspired oxygen (fiO2) on the ventilator. A chest radiograph obtained at that time demonstrated a large
pleural effusion with leftward mediastinal shift, which required an emergent needle
thoracentesis and chest tube placement. The patient was found to have coagulase-negative
Staphylococcus sepsis, which caused a septic ileus that led to the initial abdominal distension.
The pleural effusion was a separate clinical event that temporally coincided with
the abdominal distension, but was not recognized by the medical team as they prioritized
evaluation for an intra-abdominal pathology, and initially ascribed the respiratory
distress as secondary to a ‘competitive abdomen’ given the abdominal distension.
Case 6
A 40-week gestation infant was born by SVD. The mother had regular prenatal care with
unremarkable prenatal imaging. After delivery, the patient was noted to have sustained
desaturations, so the infant was transferred to NICU for further evaluation. A chest
radiograph on admission demonstrated 13 ribs, which was not noted on the radiologist's
report or recognized by the on-call neonatologist. The following day, the NICU team
noted the presence of an additional rib on the radiograph as well as concern for cardiomegaly.
At this time, the patient continued to have desaturations and developed clinical signs
and symptoms of respiratory distress (retractions and tachypnea) including stridor.
Further work-up was undertaken at that time of multiple organ systems. Follow-up chest
radiographs confirmed the presence of 13 ribs. An echo demonstrated significant outflow
tract dilation of both the aortic root and pulmonary artery in addition to large atrial
septal defect and VSD. Bedside, flexible nasopharyngoscopy by a pediatric otolaryngologist
demonstrated paralysis of the left vocal cord, which was the cause of the stridor.
Renal and head ultrasounds (USs) were obtained and both were normal. This cardiac
abnormality was concerning for an underlying genetic etiology, so a whole exome sequencing
genetic test was performed at the request of the genetics team. The testing identified
a single missense variant (c.829T > A; p.W277R) in the TGFBR1 gene consistent with
Loeys–Dietz type 1. The parents were counseled extensively on the diagnosis, then
elected to proceed with cardiac repair. The patient has since been discharged from
the NICU, and is being followed outpatient in the Cardiology, Genetics and Complex
Care clinics. While the diagnostic error in this case did not markedly impact the
patient's clinical status, we included it in this case series to highlight a diagnostic
error which did not markedly impact the final outcome, but it demonstrates potential
for improvement in the diagnostic process for the future.
Case 7
A 39-week gestation infant was born by scheduled C-section after a prenatal diagnosis
of severe left-sided congenital diaphragmatic hernia (CDH). The patient was treated
with extracorporeal membrane oxygenation (ECMO) for 16 days after delivery and underwent
surgical repair of the CDH while on ECMO. After ECMO, the patient required long-term
ventilator support in the NICU as well as tracheostomy and gastrostomy-tube (g-tube)
placement. The patient was on prolonged diuretic therapy due to chronic lung disease.
At 5 months of age, the patient had persistent feeding intolerance, so a CT abdomen
was obtained to evaluate for reherniation of the CDH. Incidentally, the CT report
noted a 5-mm nonobstructing calculus in the lower pole of the left kidney. This was
not followed up on or noted in the patient's chart by the neonatology team. At 7 months
of age, the patient developed persistent hematuria. A renal US was obtained to evaluate
for a cause of the hematuria and noted the calculus—which remained nonobstructive,
but had grown in size. The neonatology team then became aware of the prior CT report
of the calculus—the source of the persistent hematuria. The feeding difficulties slowly
improved, and the patient was eventually able to tolerate full enteral feeds. As the
renal calculus was not obstructive, the neonatology clinicians in consultation with
the pediatric urology service elected to follow with serial imaging. The calculus
has remained stable in size and no evidence of obstruction on follow-up USs. The hematuria
has since resolved. If the calculus becomes obstructive or if the patient develops
a urinary tract infection or urosepsis in the future, then the plan is for urologic
intervention at that time.
Incorrectly Interpreted Echocardiographic Imaging
Case 8
A 34-week gestation infant was born by an ex utero intrapartum treatment (EXIT) procedure
for severe left-sided CDH after in-utero placement of an airway balloon by a fetal
surgeon to improve lung growth. Following a prenatal diagnosis of CDH and in-utero
placement of an airway balloon by a fetal surgeon, the mother developed preterm labor,
so the infant was delivered at 34 weeks of gestation by the EXIT procedure. A prenatal
echo had demonstrated normal cardiac anatomy. A postnatal echo on the day of birth
identified a pulmonary vein on the right side returning to the left atrium, but did
not visualize a pulmonary vein on the left side. This was not followed up by the neonatologist
or cardiologist. The patient was treated with ECMO and surgical repair of the CDH,
followed by a prolonged NICU stay requiring long-term ventilator support. Over the
course of 3 months, nine limited echos were performed to evaluate for pulmonary hypertension,
but the full cardiac anatomy was not assessed on these studies. Several months later,
a CT heart was obtained to evaluate for another medical issue, which incidentally
noted partial anomalous pulmonary venous return (PAPVR) of the left lingular and lower
pulmonary veins, which formed a confluent channel draining to the left innominate
vein. This was confirmed by a repeat full anatomic echo. After further discussion
with the cardiology and cardiothoracic surgery clinicians, it was determined that
while this finding had been missed on previous studies, surgical intervention was
not warranted at that time. The patient remained in the NICU for several months, and
required tracheostomy placement due to inability to safely wean from the ventilator.
There were no additional concerns from a cardiac standpoint during admission. The
patient has now been discharged from the NICU, and is being followed in the cardiology
clinic. The plan from a cardiac perspective is to allow the patient to continue to
grow, then for surgical repair of the PAPVR at a yet to be determined date in the
future.
Inadequate Team Communication
Case 9
A 31-week gestation infant was born by C-section due to poor fetal biophysical profile.
A prenatal US had noted that the stomach was not visible. A subsequent US did not
visualize the stomach or other portions of the gastrointestinal (GI) tract, a finding
suggestive of tracheoesophageal fistula (TEF) or other GI tract abnormality. The obstetric
team communicated the concern regarding the GI tract to the neonatologist attending
the delivery, but these concerns were not relayed to the admitting neonatologist.
No diagnostic testing was performed for GI anomalies. An abdominal radiograph performed
to evaluate placement of an UVC noted an incidental finding of a rounded air collection
in the upper mediastinum. An orogastric tube (OGT) was placed, but could not be advanced,
and a radiograph demonstrated the OGT in the upper mediastinum with air distally in
the GI tract, a finding suggestive of esophageal atresia with a TEF. This was confirmed
on subsequent radiograph, in which the OGT was curled in the upper esophagus, and
could not be advanced distally due to esophageal atresia. The decision was made to
proceed to the operating room for surgical repair, and upon thoracotomy by the pediatric
surgery team, and a type-C TEF was found and subsequently repaired. The patient had
an uneventful recovery postoperatively, however, did require g-tube placement for
enteral feeds due to inadequate oral feeding skills. The patient was discharged after
several months in the NICU breathing room air and on full enteral feeds via the g-tube.
Since discharge, the patient has required esophageal dilation by pediatric surgery.
No Fault
Case 10
A 34-week gestation infant was born by stat C-section due loss of fetal heart tones
during routine fetal monitoring while the mother was at a prenatal appointment. During
the pregnancy, the patient was diagnosed with multiple congenital anomalies, and the
mother had undergone a fetal MRI, which demonstrated atresia of the jejunum with perforation,
formation of meconium pseudocyst, lower urinary tract obstruction, arthrogryposis,
and bilateral clubfeet. Prenatal genetic testing showed a chromosome 6 triplication.
The patient was treated with intubation for respiratory distress, mechanical ventilation,
a laparotomy to excise the jejunal atresia and a meconium pseudocyst, and creation
of a jejunostomy. Postoperatively, the patient required prolonged mechanical ventilation,
vasoactive support, and high-dose steroid administration. Genetic testing confirmed
a chromosome 6 triplication. The patient had persistent hyperglycemia, which was initially
ascribed to high-dose steroid administration. An insulin drip was initiated, but the
patient's blood glucoses remained persistently elevated. An endocrinology consult
and a literature review yielded the information that neonatal diabetes can be associated
with chromosome 6 triplication. The patient was ultimately diagnosed with neonatal
diabetes secondary to the chromosomal abnormality, and not due to high-dose steroid
requirement as initially thought. Due to the extremely rare nature of this chromosome
6 triplication, the association with neonatal diabetes would not generally be considered
in the typical differential diagnosis for neonatal hyperglycemia.
Discussion
This case series, the first of its kind to describe nonlethal diagnostic errors in
the NICU, includes 10 cases categorized as cognitive, systems-based, or no-fault diagnostic
errors.[6] The majority were cognitive in origin (see [Table 1]). We included an example of a no-fault diagnostic error—defined as a highly atypical
presentation which is undetectable in spite of adequate diagnostic work-up[6]—to illustrate a diagnosis which would remain indiscernible despite a reasonable
diagnostic evaluation, and thus would most likely not be amenable to interventions
directed at improving diagnostic errors. Some of the cases had multiple diagnostic
errors or involved multiple medical teams, which demonstrates the often multifactorial
nature of diagnostic errors in a complicated environment such as the NICU. The outcome
of these diagnostic errors varied as well—from no obvious harm, as in the patient
with the missed radiologic finding of 13 ribs, to life-threatening, as in the patient
with the missed pleural effusion requiring emergent needle thoracentesis. Fortunately,
no patient died from diagnostic errors in this case series. We identified these diagnostic
errors during the course of our clinical work in our NICU without any attempt to systematically
perform surveillance for such errors, and described these cases to raise awareness
of this problem in neonatology, and to highlight the need to systematically study
these errors, which have been thus far relatively neglected in the patient safety
movement. The chief limitation of our study is our inability to perform an in-depth
analysis of the causal and contributory factors (particularly the cognitive processes
involved) to the diagnostic errors we described. Therefore the categorization of these
errors is solely based on the information available to us on chart review. In conclusion,
a wide range of diagnostic errors may occur in NICU patients, and further research
should address methods to identify, measure, and classify these errors and their impact.
We are currently conducting a formal study to determine the incidence, types, and
impact of diagnostic errors in the NICU, and we are using the cases described in this
manuscript as prototypical cases to develop and refine our detection instrument, a
modification of the Safer Dx instrument.[7]
Table 1
Initial presentation, missed diagnosis, main disease category, and etiology of the
diagnostic error for the examples of diagnostic error presented in this case series
|
Case (n = 10)
|
Initial presentation
|
Missed diagnosis
|
Main disease category
|
Etiology of the diagnostic error
|
|
1
|
Premature delivery at 31 wk
|
HSV keratitis
|
Infectious disease and ophthalmologic
|
Cognitive
|
|
2
|
Term delivery
|
Imperforate anus
|
Gastrointestinal
|
Cognitive
|
|
3
|
Multiple congenital anomalies
|
Coarctation of the aorta
|
Cardiovascular
|
Cognitive
|
|
4
|
Premature delivery at 34 wk after maternal PPROM
|
NEC and E. Coli bacteremia
|
Gastrointestinal and infectious disease
|
Cognitive and systems-based
|
|
5
|
Premature delivery at 24 wk with abdominal distension
|
Pleural effusion
|
Respiratory
|
Cognitive and systems-based
|
|
6
|
Term delivery with desaturations
|
13 ribs
|
Orthopedic
|
Cognitive
|
|
7
|
CDH with hematuria
|
Renal calculus
|
Renal
|
Cognitive
|
|
8
|
CDH with ventilator dependence
|
PAPVR
|
Cardiovascular
|
Cognitive
|
|
9
|
Premature delivery at 31 wk
|
TEF
|
Gastrointestinal
|
Systems-based
|
|
10
|
Persistent hyperglycemia in a critically-ill neonate with multiple congenital abnormalities
|
Neonatal diabetes related to chromosome 6 duplication
|
Endocrine
|
No fault
|
Abbreviations: CDH, congenital diaphragmatic hernia; E. coli, Escherichia coli; HSV, herpes simplex virus; NEC, necrotizing enterocolitis; PAPVR, partial anomalous
pulmonary venous return; PPROM, preterm premature rupture of membranes; TEF, tracheoesophageal
fistula.
