Ann Thorac Surg 2006;81:721-723
© 2006 The Society of Thoracic Surgeons
Case report
Cerebral Air Embolism During Imaging of a Sentinel Lymphatic Drainage in the Respiratory Tract
Kazuhiro Ueda, MD
a
,
*
,
Yoshikazu Kaneda, MD
a
,
Manabu Sudo, MD
a
,
Mitsutaka Jinbo, MD
a
,
Kazuyoshi Suga, MD
b
,
Kimikazu Hamono, MD
a
a First Department of Surgery, Yamaguchi University School of Medicine, Ube, Yamaguchi, Japan
b Department of Radiology, Yamaguchi University School of Medicine, Ube, Yamaguchi, Japan
Accepted for publication November 12, 2004.
* Address correspondence to Dr Ueda, Yamaguchi University School of Medicine, 1–1–1 Minami-Kogushi, Ube Yamaguchi 755–8505, Japan (Email: kaueda{at}c-able.ne.jp).
 |
Abstract
|
|---|
We report a rare but notable case of cerebral air embolism complicating transthoracic intrapulmonary injection of an imaging agent used to locate sentinel lymph nodes. After a bolus injection of 2 mL of iopamidol into the peritumoral area with a 23-gauge needle, the patient complained of complete paralysis on his left side. Intraaortic gas was detected by computed tomography immediately after the injection. The patient recovered spontaneously without any additional complication. Surgeons should be aware of this rare but possible complication during sentinel lymph node assessment.
|
Introduction
|
|---|
Since Liptay and colleagues showed that sentinel lymph node mapping improves the detection of nodal micrometastasis in patients with nonsmall cell lung cancer [1], many investigators have explored the usefulness of various modalities in identifying the sentinel node [2–5]. However, little is known about the complications of sentinel lymph node assessment in the respiratory tract. Herein, we describe a case of cerebral air embolism complicating transthoracic intrapulmonary injection of an imaging agent used to locate the sentinel lymph node.
A 77-year-old man was admitted to our hospital for suspected lung malignancy. The primary tumor was 5 cm in diameter and was located in the left lower lobe (S6). Although no motor paralysis was present at the time of admission, the patient's history included cerebral infarction. On the basis of a clinical diagnosis of T2N0M0 lung cancer, he was considered eligible for indirect computed tomographic lymphography for the purpose of locating a sentinel lymph node [3] to be followed by surgery. With the patient in the prone position, the local anesthesia was achieved with a total of 5 mL of 1% lidocaine hydrochloride at the injection site. An injection of 2 mL of iopamidol (Iopamiron 300 [Nippon Shering, Osaka, Japan]), targeted to the periphery of the tumor, was given through a 23-gauge needle attached to a 2.5 mL syringe (Fig 1). This contrast agent, which is conventionally used as an extracellular contrast agent for angiography and enhanced computed tomography, has an iodine concentration of 300 mg/mL, an osmolarity of 585 mOsm/kg, a viscosity of 4.4 mPa/s, and a pH of 6.5 to 7.5. Indirect lymphography scans at full inspiration with predefined measurements were obtained successively at 30 seconds, and at 1, 3, and 5 minutes after the iopamidol injection. Immediately after the last scan, the patient complained of complete paralysis on his left side. Intra-arterial gas noted on the computed tomographic scan at 1 minute after the injection was strongly suggestive of cerebral air embolism (Fig 2). Fortunately the patient recovered spontaneously and fully during 15 minutes of placing the patient in the Trendelenburg position to keep air out of the cerebral circulation. Magnetic resonance imaging of the brain on the following day showed no abnormality.
View larger version (129K):
[in this window]
[in a new window]
|
Fig 1. With the patient in the prone position, the contrast material is injected into the peritumoral area under full inspiration to image the lymphatic drainage system.
|
|
View larger version (135K):
[in this window]
[in a new window]
|
Fig 2. Intra-arterial gas is detected in the descending aorta 1 minute after the injection of contrast material.
|
|
|
Comment
|
|---|
Air embolism is recognized as a rare but potentially fatal complication of transthoracic lung needle biopsy with a reported incidence of 0.07% [6]. Thoracic surgeons have also experienced this problem during insertion of a hook-type marker into the lung parenchyma to locate small or impalpable tumors [7]. The air embolism may be caused primarily by the pulmonary puncture itself, which can open a communication between a bronchiole and contiguous pulmonary vein [6, 7]. Therefore, care should be taken during sentinel lymphatic drainage assessment that requires pulmonary puncture for delivering an imaging agent into the tumor or peritumoral area.
We have performed sentinel lymph node assessment in patients with lung cancer since August 2001, with the approval of our institutional review board. Initially, we injected radiolabeled tin colloid into the peritumoral area with computed tomographic guidance for intraoperative detection of radioactive lymph nodes by means of a hand-held 
-detecting probe [2]. We now use iopamidol as the contrast material to image the lymphatic drainage preoperatively by means of computed tomographic lymphography [3]. We have performed this procedure in 42 cases to date without significant adverse effects, except in 1 patient who required transient chest tube drainage for moderate pneumothorax. Although the patient described herein recovered fully without any treatment, air embolism can occasionally be fatal [7]; five of 12 reported cases developing systemic air embolism were fatal despite intensive treatment.
Treatment of systemic air embolism consists of placing the patient in a left lateral decubitus position (to prevent air within the left atrium from embolizing systemically) or in the Trendelenburg position. Ventilatory support with 100% oxygen should be administered to promote resorption of air bubbles. Transfer to a hyperbaric chamber may improve survival after air embolization.
Little is known about risk factors for air embolism complicating pulmonary puncture. Positive airway pressure with mechanical ventilation, coughing, puncturing through disease lung (with air trapping), puncturing with a large needle (19 gauge or larger), and deep puncturing are all considered risk factors because they are thought to promote air aspiration by airway-venous communication, as well as increase the opportunity for such communication. This hypothesis is based in part on the fact that puncturing of a collapsed lung during one-lung ventilation has never caused air embolism. The patient reported herein, as well as some of our other patients, had a fit of coughing that continued about 10 to 20 seconds as a natural reflex after injection of the imaging agent. The large tumor in the present case might contribute to development of air trapping at the periphery of the tumor. In addition, the tumor in the present case was situated away from the visceral pleura and required deep injection (albeit, a 23-gauge needle was used). It is also possible that cerebral ischemic disease exacerbated the symptoms of cerebral air embolism.
The lung is a unique organ with respect to sentinel lymph node mapping because of the possibility that tracer injection will cause an air embolism. Because air embolism is a serious and sometimes fatal complication, a large tumor and a centrally located tumor should not be considered for sentinel lymph node assessment in this manner.
|
References
|
|---|
- Liptay MJ, Grondin SC, Fry WA, et al. Intraoperative sentinel lymph node mapping in non-small cell lung cancer improves detection of micrometastases J Clin Oncol 2002;20:1984-1988.[Abstract/Free Full Text]
- Ueda K, Suga K, Kaneda Y, et al. Radioisotope lymph node mapping in nonsmall cell lung cancercan it be applicable for sentinel node biopsy?. Ann Thorac Surg 2004;77:426-430.[Abstract/Free Full Text]
- Ueda K, Suga K, Kaneda Y, Li TS, Ueda K, Hamano K. Preoperative imaging of the lung sentinel lymphatic basin with computed tomographic lymphographya preliminary study. Ann Thorac Surg 2004;77:1033-1037.[Abstract/Free Full Text]
- Sugi K, Kaneda Y, Sudoh M, Sakano H, Hamano K. Effect of radioisotope sentinel node mapping in patients with cT1 N0 M0 lung cancer J Thorac Cardiovasc Surg 2003;126:568-573.[Abstract/Free Full Text]
- Nakagawa T, Minamiya Y, Katayose Y, et al. A novel method for sentinel lymph node mapping using magnetite in patients with non-small cell lung cancer J Thorac Cardiovasc Surg 2003;126:563-567.[Abstract/Free Full Text]
- Sinner WN. Complications of percutaneous transthoracic needle aspiration biopsy Acta Radiol Diagn (Stockh) 1976;17:813-828.[Medline]
- Sakiyama S, Kondo K, Matsuoka H, et al. Fatal air embolism during computed tomography-guided pulmonary marking with a hook-type marker J Thorac Cardiovasc Surg 2003;126:1207-1209.[Free Full Text]
Top
Abstract
Introduction
