Case Report
A 15 year-old, 68 kg female with a history of idiopathic scoliosis was
scheduled for thoracolumbar posterior fusion and instrumentation (levels
T3-L4). Additional past medical and surgical history were unremarkable,
without allergies or chronic medications. Induction of general
anesthesia was achieved with intravenous lidocaine, Propofol, fentanyl,
and succinylcholine. Following easy mask ventilation, the patient was
intubated uneventfully via direct laryngoscopy with a 7.0 cuffed
endotracheal tube. Total intravenous anesthesia (TIVA) with Propofol,
remifentanil, and dexmedetomidine infusions was utilized for
maintenance. Additionally, infusions of aminocaproic acid and
nicardipine were employed for fibrinolysis and intermittent
hypertension, respectively. The patient was turned to the prone position
with no change in oxygenation or ventilation and all other vital signs
were stable.
Ventilator settings included fraction of inspired oxygen (FiO2) 0.4,
tidal volume (TV) 470cc, respiratory rate (RR) 11, and positive end
expiratory pressure (PEEP) 5 cmH2O. Four hours
post-induction, the first arterial blood gas (ABG) analysis showed
7.42/33/231/22/-3/99% with hemoglobin (Hgb)/hematocrit (Hct) = 8.5/25.
Estimated blood loss (EBL) at that time was approximately 500cc. One
hour later, the surgeon noticed cerebrospinal fluid in the operative
field resulting from a dural tear at T2-T3. A pediatric
neurosurgeon was consulted and a lumbar drain was placed at L2-L3.
During this period, the patient became mildly hypotensive with a blood
pressure (BP) of 93/53 mmHg, however oxygenation and ventilation
remained stable. At this point, 1000cc of 5% albumin and 2500cc of
crystalloid had been administered along with a transfusion of 60cc Cell
Saver. Later on a second ABG analysis was obtained with normal results
except for a low hematocrit: 7.43/37/218/24/0/99% with Hgb/Hct =
6.1/18. Two units packed red blood cells were transfused, the blood
pressure stabilized, and the surgeon began closing. While still prone,
the patient was transitioned to pressure support (PS) ventilation with
settings of PS 14, PEEP 5, FiO2 0.4, RR 17-20, achieving tidal volumes
of 350cc. The FiO2 was then increased to 1.0 in preparation for
returning to supine position and emergence. All infusions were
discontinued prior to turning supine, and acetaminophen 1000mg,
hydromorphone 0.6mg, fentanyl 200mcg, were administered intravenously.
Total fluids given for the case were 1000cc albumin 5% and 4000cc
crystalloid, 60cc Cell Saver and 2 units packed red blood cells. Urine
output was 3475cc with an EBL of 1000cc.
By the end of the case, the patient had been spontaneously ventilating
with pressure support during wound closure for 30 minutes. The
respiratory rate was 17-20 breaths/minute and TV 350-450cc. All vital
signs were normal. Residual neuromuscular blockade was reversed, and the
patient was turned supine. Immediately upon turning supine, her pulse
oxymetry decreased to 65% with mild hypotension (BP 96/40) and a heart
rate (HR) of 80. She became tachypneic (RR 30) with TV decreased to
around 150cc. Respirations were supported with intermittent manual
ventilation at an FiO2 of 1.0 over the next three minutes. This resulted
in a slow, but steady increase in oxygenation to 89%. Over the next 5
minutes the oxygenation continued to rise slowly to 96%. Breath sounds
were equal bilaterally without wheezing at the apices anteriorly, but
were difficult to auscultate posteriorly. After 30 minutes, the patient
was awake and appropriately following commands with unsupported TV of
250-275cc, RR 30, BP 121/53, HR 92, and oxygen saturation of 97%. The
patient was extubated, after which, she immediately desaturated to 83%
but was otherwise hemodynamically stable. Ventilation was assisted via
bag-mask, but she remained tachypneic achieving poor TV (approximately
200cc) with good mask seal. A stat portable chest x-ray revealed a
moderate right-sided pneumothorax. ABG analysis showed hypoxemia and
respiratory acidosis 7.28/53/89/25/-2/96, Hgb/Hct=8.2/24. The patient
was sedated in the operating room and the surgical team, under local
anesthesia, placed a chest tube. The patient’s oxygenation immediately
improved to 100%. She was then transported to the intensive care unit.
The chest tube was removed on post-op day (POD)#1, her lumbar drain was
removed POD#2, and the remainder of her hospital course proceeded
uneventfully with discharge on POD#5. The patient and family were very
satisfied with their care.