Keywords
diaphragmatic paralysis - neonate - central venous catheter - diaphragmatic plication
We report a case of an 800 g preterm female born at 26 weeks' of gestation to a 30-year-old
mother para 2 gravida 2. Ultrasound scans during pregnancy were normal. The pregnancy
was complicated by a threat of premature delivery at 23 weeks' of gestation with rupture
of membranes and chorioamnionitis.
At birth, the neonate was intubated and received intratracheal instillation of exogenous
surfactant for a respiratory distress syndrome (RDS). The first chest X-ray showed
signs of RDS without diaphragmatic abnormalities ([Fig. 1A]). Extubation was possible at 12 hours of life relayed by nasal intermittent positive
pressure ventilation (NIPPV).
Fig. 1 (A) Chest X-ray on DOL 1: no diaphragmatic abnormalities; (B) chest X-ray on DOL 11: catheter extravasation; (C) chest X-ray on DOL 71: elevated diaphragmatic dome, and an asymmetry of position
between the left and right hemidiaphragm; (D) chest X-ray on DOL 101: recovery of normal diaphragmatic position. DOL, day of life.
Puncture for the venous catheter's placement was on the right forearm, at day 1 of
life, located in central position, as confirmed by the X-ray, and a parenteral nutrition
hyperosmolar fluid was infused. Decreasing respiratory support was possible on day
4 with the use of a nasal continuous positive airway pressure (nCPAP). On day 11 of
life, the neonate was intubated and ventilated with high-frequency oscillatory ventilation
for severe respiratory distress. Indeed, we noted a decrease in the right basal breath
sound; the respiratory frequency was around 55/min, oxygenation at 88% without oxygen
therapy, the capillary blood gas showed a pH = 7.35 and a blood carbon dioxide measure
at 78 mm Hg. On the same day, a chest radiograph was practiced and confirmed a right
pleural effusion secondary to an extravascular diffusion of the central right venous
catheter in the right pleural space ([Fig. 1B]). No pleural drainage was required, the catheter was removed, and another catheter
was placed on the left leg. The chest radiographs performed the day after the effusion
showed that the right hemidiaphragm was elevated ([Fig. 1C]). At that moment, the osmolarity of the fluid was 1,136.43 mOsm/L, the total volume
was 56 mL/d, and it was composed of electrolytes (sodium, potassium, magnesium, calcium,
and phosphor), glucose, amino acids, and vitamins.
We suspected a hemidiaphragmatic paralysis (HDP) and performed a right diaphragmatic
ultrasound on day 25 of life, revealing the absence of mobility of the right hemidiaphragm,
in comparison to a normal mobility of the left hemidiaphragm. The decrease of mechanical
ventilation pressure was associated with the emergence of clinical signs of respiratory
distress. A chest radiograph performed at these moments showed a worsening of the
right hemidiaphragm's elevation, reversible when increasing the mechanical ventilation
pressure. Due to the difficulties in obtaining optimal respiratory support due to
the right HDP, a multidisciplinary meeting was organized to discuss a surgical intervention.
Surgery carries risks, including exposing the patient's brain to the anesthetics'
toxicity, infectious risk, postoperative complications, and others. Front to the low
age of the infant and no insurance of a significant respiratory benefit after surgery,
it was decided to proceed with conservative medical treatment consisting of prolonged
respiratory support. Systemic corticosteroids were introduced on day 47 of life for
bronchopulmonary dysplasia (BPD). Gradual improvement (clinical and biological) was
observed and extubation was possible at day 64 of life, facilitated first by a NIPPV
and then nCPAP.
The right hemidiaphragm did not elevate and stayed in normal position even after decreasing
the respiratory support, as illustrated on chest radiographs. The diaphragmatic position
was normal on the chest radiograph performed on day 101 ([Fig. 1D]). A second ultrasonography was performed just before discharge, confirming the complete
diaphragmatic recovery, and the patient was eventually discharged from the hospital
at day 143 of life without any respiratory support or oxygen supplementation.
Discussion
The peripherally inserted central venous catheter, to infuse hyperosmolar nutritional
fluid to neonate who cannot yet support enteral nutrition, is one of the most common
invasive procedure, in neonatal intensive care units. In this case, we report a rare
cause of HDP in a preterm infant, with spontaneous improvement and recovery without
surgical treatment. HDP in the neonatal period can be caused by nerve injury[1] during central venous catheter insertion, thoracic surgery, a traumatic delivery
(brachial plexus injury[2]), and rarely by phrenic nerve injury after catheter fluid extravasation.[3] Difficult breech delivery carries the highest risk of traumatic delivery-induced
phrenic nerve palsy. Bilateral diaphragmatic paralysis requires further exploration
as primary muscular pathology, brain stem hemorrhage,[4] and hypothyroidia[5] can be suspected in that case.
Only a few cases have been reported of unilateral HDP secondary to extravasation of
parenteral nutrition infusion of hyperosmolar fluids through a central venous catheter.[3]
[6]
[7] One case of pleural effusion caused by extravasation of nutritional fluid in the
pleural space has been described[8] causing no direct HDP. Indeed, the HDP described, in this case, was a complication
of the thoracocentesis performed to evacuate the pleural liquid. Tosello et al described
two cases[3]: surgical treatment was required for one case (left diaphragmatic plication) on
day 87 (postoperative recovery was favorable), in the second case, prolonged mechanical
ventilation was required, and recovery was spontaneous around day 130. A third case
was reported in 1995 concerning an infant of 30 weeks' gestational age,[6] corticosteroids were introduced on day 34 of life, noninvasive ventilation was required
until day 45 of life, and the outcome was favorable, despite the absence of mobility
of the right hemidiaphragm after medical treatment. Extravasation of fluid in the
pleural space could be secondary to a local mechanical injury caused by the catheter
itself, but also to the local toxicity of the infused fluids. This second hypothesis
highlights the importance to check regularly, preferably by ultrasound monitoring,
the catheter's position to confirm its central position, allowing the infusion of
hyperosmolar fluids which cannot be used in case of a peripheral position.
Although the mechanism remains unclear, the nerve injury occurring after extravasation
of an hyperosmolar fluid in the pleural space could be due to the hyperosmolarity
(usually over 800 mOsm/L on a central catheter), which is thought to cause toxicity
to surrounding tissues.[9] Also, no information was found on the benefits of a pleural drainage in case of
a low abundance pleural effusion, to diminish local nerve toxicity. HDP is suspected
in the case of respiratory distress[1]
[2]
[4]
[5]
[10] without any infectious or cardiovascular explanation and confirmed by chest radiograph[3]
[10] and diaphragmatic time-motion mode ultrasound scan.[11]
[12] On the chest radiograph, HDP is suspected from an elevated diaphragmatic dome and
asymmetry of the position between the left and right hemidiaphragm. The diaphragmatic
function can be evaluated by ultrasound scans, a noninvasive investigative tool which
does not utilize ionizing radiation. Electromyography can also be helpful but was
not performed in our case.
No specific guidelines for the treatment of this rare complication have been published.
Two opinions emerge surgical treatment (plication of the diaphragm[2]
[13]) and medical treatment, consisting of adapted respiratory support. The use of positive
pressure ventilation could maintain a pulmonary volume necessary to proper oxygenation.[3]
[5] The indications and proper timing for diaphragmatic plication surgery remain unclear.
It appears early surgery could reduce the duration of mechanical ventilation, hence
reduce the exposure to toxic medication required in mechanical ventilation. However,
there is no clear evidence to support this. Some authors have mentioned the advantages
of early surgical intervention,[14] which can indeed be discussed in our case.
In our case and in a second reported case,[3] spontaneous recoveries occurred with nonsurgical treatment. The use of corticosteroids
could decrease the inflammation caused by extravasation and improve both the diaphragmatic
function[6] and BPD, although they have to be discussed owing to their systemic effects, including
neurological. When medical treatment has chosen the risk of nosocomial infections
increases,[3] the duration of mechanical respiratory support and hence of the hospital stay is
longer. If no benefit of the corticotherapy is seen, and/or in cases of prolonged
invasive mechanical ventilation, surgical treatment should be considered. Also, the
spontaneous outcome is related to the irritative mechanism of the phrenic nerve, which
is to differentiate from a traumatic damage.
HDP is a rare complication of the peripherally inserted central catheter, secondary
to a central venous diffusion and nutritional fluid extravasation in the pleural space.
In premature infants, nutritional fluid is often hyperosmolar, hence requires a central
venous catheter. Considering that, we have to remain vigilant in case of a sudden
respiratory distress, with no infectious explanation. Although there is no specific
recommendation for the treatment of HDP, this case highlights the advantage provided
by a nonoperative treatment, with a favorable outcome in the preterm neonate.
