Keywords Dandy–Walker syndrome - acyanotic congenital heart disease - hydrocephalus - ventriculoperitoneal
shunt - anesthetic management
Introduction
Prevalence of Dandy–Walker malformation (DWM) is 5 to 8 per 100,000 live births.[1 ] In first year, 2 to 4% develop hydrocephalus and raised intracranial pressure (ICP).[1 ]
[2 ] Congenital heart disease is reported in 18%; association with tetralogy of Fallot
is high.[3 ]
[4 ]
We share our experience of managing a case of hydrocephalus with Dandy–Walker disease
(DWD) for ventriculoperitoneal (VP) shunt placement in a 2-month-old girl child who
recently recovered from COVID-19. Although shunt surgeries are routine in pediatric
patients, this case is unique because of preexisting, complicated cardiovascular anomalies,
which had a direct bearing on the neurological outcome. Also, recent history of COVID-19
posed risk for unpredictable cardiopulmonary complications.
Case Report
A 2-month-old girl child, 5 kg, presented in neurosurgical department with history
of gradually increasing head size, lethargy, poor feeding, and delayed milestone for
1 month. On examination, child was lethargic with classical features of hydrocephalus,
sunsetting eyes, macrocephaly (50 cm), and bulging fontanelles. Noncontrast CT head
revealed midline posterior fossa cystic lesion, cerebellar hypoplasia, severe hydrocephalus,
with cortical thinning ([Fig. 1 ]).
Fig. 1 CT scan showing posterior fossa cyst and hydrocephalus (large, dilated ventricles)
with cerebral cortical thinning.
During preanesthetic evaluation for ventriculoperitoneal shunt surgery, her mother
gave history of child’s recent recovery from COVID-19 1 week back. Vitals (pulse rate—110/minute,
blood pressure—110/69, respiratory rate—45/min, oxygen saturation on room air—96%)
and blood investigations were normal. Airway was apparently normal, except mechanical
issues with large head. Chest X-ray showed cardiomegaly; no radiological findings
of COVID-19 pneumonia. Electrocardiogram showed normal sinus rhythm with P-pulmonale.
2D-echocardiography revealed double-outlet right ventricle (DORV), 6-mm subaortic
ventricular septal defect (SAVSD), 3-mm patent ductus arteriosus (PDA), dilated pulmonary
artery (PA), pulmonary arterial hypertension (PAH), and left-to-right-shunt. With
these findings, a provisional diagnosis of Dandy–Walker variant with acyanotic heart
disease with left-to-right-shunt and severe PAH was made. Pediatric cardiac surgery
team reviewed the case and pulmonary artery banding (PAB), followed by VP shunt surgery
was planned. High-risk consent was obtained from parents.
Maintenance fluid half normal saline and dextrose saline was started at 20 mL/hr with
6 hours fasting. Electrocardiogram leads, noninvasive blood pressure cuff, and saturation
probe were applied, and baseline vital parameters were noted in the operation theater.
Infant was premedicated with intravenous (IV) midazolam 0.5 mg and fentanyl 20 mcg
on table under direct observation. Thiopentone 25 mg IV and a mixture of air, oxygen
(1: 1) and sevoflurane (< 1 minimum alveolar concentration [MAC]) were used for anesthetic
induction via closed circuit. A roll was placed below the child’s shoulder, head on
gelfoam ring, and body on an elevated platform (folded sheets), to facilitate endotracheal
intubation after IV vecuronium 0.6 mg and 3-minute intermittent positive pressure
ventilation (IPPV). Trachea was intubated with 3.5 mm ID flexometallic cuffed tube
and fixed at 10 cm. Oropharyngeal temperature probe was used to monitor temperature.
A 4.5F central venous access was obtained in the right femoral vein, and 22G arterial
line in left femoral artery. Urobag was emptied; patient was handed over to cardiac
surgical team. IV amikacin 30 mg and IV ceftriaxone 250 mg were administered before
surgical incision. Infusion dobutamine at 5 mcg/hr and dopamine 5 mcg/ hr were started
at thoracotomy and titrated to maintain mean blood pressure of 45 to 75 mmHg. Anesthesia
was maintained throughout the surgery with air oxygen mixture (1:1), isoflurane 1.5
to 2%, and intermittent boluses of vecuronium and fentanyl.
PDA was ligated, and PAB was performed after thoracotomy. Transient fall in oxygen
saturation (2–3%) from 98 to 99% with 50% FiO2 followed PA tightening: sign of successful banding as volume of deoxygenated blood
reaching lungs for oxygenation was reduced. A total of 100 mL of packed red blood
cells (RBC) was transfused. Blood sugar was checked and recorded. After PAB, PA pressure
was 26/14 mmHg with systemic pressure of 80/40 mmHg.
Postthoracotomy closure, position of the patient's head was turned 90 degrees to allow
access for neurosurgery. Ventricular end of the shunt was inserted at the frontal
horn of right lateral ventricle and free flow of cerebrospinal fluid (CSF) was obtained
at the abdominal end.
Surgery lasted for 2.5 hours, total input was 80 mL, and urine output was 20 mL. Patient
was shifted to cardiothoracic and vascular surgery (CTVS) ICU for overnight elective
mechanical ventilation, sedated, and paralyzed. Next morning, infusion of vecuronium
was stopped, infusion of fentanyl tapered off, and patient’s trachea was extubated
after blood gas analysis showed PaO2 105 mmHg at FiO2 30%. Infusion of dopamine at 5mcg/kg/min and dobutamine 5mcg/kg/min
was tapered and discontinued. The child remained in ICU for 3 days. Her sensorium
improved, and she was discharged on postoperative day 10 from the ward active and
accepting feeds.
Discussion
Anesthetic management was different from routine VP shunt surgeries because of the
preexisting complex cardiac anomalies and a recent recovery from COVID-19, verified
by negative reverse transcription polymerase chain reaction (RT-PCR) report. Recovery
from COVID-19 in children can be prolonged, and defining recovery, based on a negative
RT-PCR report, can be tricky, given its low reliability in children. Pediatric COVID-19
disease can range from being asymptomatic with high viral load to multiorgan inflammatory
syndrome. Perioperative concerns for surgery in such cases are false-negative RT-PCR
in children, low yield of viral ribonucleic acid (RNA) from nasopharyngeal samples,
nonspecific symptomatology, risk of perioperative viral aerosolization, postviral
reactive airway with critical respiratory events during extubation, unexpected postop
ventilation, and myocarditis (38–50%).[5 ]
[6 ]
[7 ] Data on clinical outcomes in pediatric patients with COVID-19 undergoing emergency
surgery is sketchy and mostly extrapolated from adult studies.[5 ]
[6 ]
[7 ] This was a multidisciplinary effort involving cardiac- and neuroanesthesiologists
and cardiac and neurosurgeons with perioperative intensive care management for successful
outcome.
Goal of perioperative management was to maintain balance between cardiac and cerebral
physiology, so that cerebral perfusion was adequate and ICP changes were minimal along
with maintaining systemic vascular resistance and optimal cardiac output to prevent
intracardiac shunt flow reversal.
Anesthesia was induced, avoiding excess sympathetic stimulation, hypercapnia, and
hypoxia to prevent PA pressure and ICP fluctuation.[2 ]
[3 ]
[8 ]
[9 ] We used sevoflurane (< 1 MAC) and thiopentone for induction. Use of sevoflurane
is associated with possibility of raised ICP. However, open fontanelles in this age
group and use of sevoflurane in low concentration can seldom cause rise in ICP. Alternatively,
IV induction may be a preferred technique. Midazolam and fentanyl, as premedication,
alleviated intubation response and surge in ICP; balanced air oxygen mixture maintained
cerebral blood flow and metabolic rate.[3 ]
[6 ] Nitrous oxide was avoided as it increases cerebral blood flow, ICP, at higher concentration
and reverses protective hypoxic pulmonary vasoconstriction, which is deleterious for
causing shunt reversal.[2 ]
[8 ]
[9 ] Ventilatory setting was guided by capnography (ETCo2 30–35 mmHg), which maintained
normocapnia. Meticulous invasive hemodynamic monitoring, prophylactic inotropes after
thoracotomy, and judicious fluid administration with blood transfusion helped to maintain
mean arterial pressure (MAP) (45–75 mmHg) and hematocrit (35%). Temperature was monitored
and normothermia was maintained as children are prone to hypothermia, because of larger
surface area and more so in this child, as thoracotomy was done and expected insensible
loses were higher.
Patients with acyanotic heart disease with left-to-right-shunt and severe PAH often
present with congestive heart failure and failure to thrive with recurrent chest infection
due to increased pulmonary flow.[6 ] So, ligation of PDA and PAB were performed as a palliation to limit the pulmonary
flow.[9 ]
The rationale behind performing cardiac corrective surgery before shunt placement
is open cerebral fontanelles at this age, which compensates for raised ICP.[5 ] Signs of hydrocephalus were present, but her neurological status permitted the team
to perform the shunt placement after the PAB and PDA ligation.
Children with DWM with recent history of COVID-19 infection can potentially present
with additional cardiorespiratory complications. To achieve successful postoperative
outcomes in such cases, detailed evaluation of central nervous system, cardiorespiratory
function, and airway is necessary. The key to manage these cases is to preserve the
delicate interplay between cerebral and cardiac physiology.
