Discussion:
Pulmonary air embolism is a serious medical emergency with significant
clinical outcome that can result in death. It represents one of the
deadly complications of central venous line insertion and removal
[6]. The patient once suspected of having venous air embolism should
be placed in the left lateral decubitus position with head down or
Trendelenburg position to allow air bubbles to stay in the upper most
part of the right ventricle which avoids further movement of the air
bubbles into the pulmonary trunk and hence causing less embolization
[11,12].Further management should include providing supplemental
oxygen to increase the partial blood oxygen pressure and decrease the
partial blood nitrogen pressure which will cause the nitrogen to diffuse
from the air bubbles which has a high nitrogen pressure into the blood
where it has a low pressure and thereby decreasing the air bubble size
[13].Treatment with hyperbaric oxygen has been known to drop the
mortality rate for severe cases particularly if used within 3 hours of
onset of air embolism [9,15,16]. Preventive measures to be taken
when inserting or removing a central venous line has been known for
proper positioning of the patient in the Trendelenburg position
especially for jugular and subclavian venous lines or supine for femoral
lines, in addition to taking care of the patient volume status, and
instructing the patient to do Valsalva maneuver or exhale during removal
of the line [14]. In this paper, we are describing a case of
suspected multiple sclerosis who presented with bilateral optic neuritis
and was initially managed with pulsed steroids with no improvement then
shifted to plasma exchange through a right jugular venous catheter
through which he received 7 sessions of plasma exchange and upon removal
of the jugular venous catheter in the sitting position he immediately
developed shortness of breath with severe hypoxia and was found to have
air bubbles in the left side of his heart due to a patent foramen ovale.
He also developed acute respiratory distress syndrome and was shifted to
the intensive care unit on high flow nasal canula. Within six hours of
the event, he was started on hyperbaric oxygen and showed significant
improvement. With extensive literature review on Pubmed, multiple cases
were reported on the development of air embolism particularly causing
cerebral air embolism through paradoxical air embolism following the
removal of central venous catheters [17-20].Cases of pulmonary air
embolism have also been reported following venous catheterization or
removal [21-23]. Physician awareness of this potentially lethal
complication of central venous catheterization or removal has been
reported to be inadequate in a study done by Ely et.al. where it was
found that around 42% of the 140 physicians who were surveyed did not
show concern for air embolism when inserting a central venous line,
although, 91% chose the Trendelenburg position during insertion, only
26% of the physicians reported concern for air embolism during central
venous line removal , and around 13.9% of the physicians admitted
elevating the head of the bed during central venous line removal which
can potentially increase the risk of air embolism [24].
The main purpose of this paper is to emphasize on the importance of
taking preventive measures to prevent air embolism when inserting or
removing a central venous line and to increase the awareness among
physicians to keep a high index of suspicion for such a serious
complication. This paper also discusses the importance of commencing
hyperbaric oxygen therapy in severe cases as it has shown effectiveness
in reducing the size of air embolism and related morbidity. To conclude,
Pulmonary air embolism related to central venous catheters insertion or
removal, although uncommon, has been reported in the literature and
physicians should keep in mind certain preventive measures when dealing
with central venous catheters to prevent such a serious complication.