Abstract

Hemothorax resulting from perforation of a great vessel is an uncommon but life-threatening complication which may occur during central venous insertion of a hemodialysis catheter. We describe a 78-year-old uremic female who developed unexplained and refractory shock on the completion of percutaneous placement of a hemodialysis catheter in the right subclavian vein under general anesthesia. Bedside transthoracic ultrasound revealed a large anechoic area above the right hemidiaphragm, suggestive of the presence of extensive hemothorax. The diagnosis was further confirmed by prompt drainage of fresh blood from the right thoracostomy tube. Emergent thoracotomy was performed and perforation of the superior vena cava was identified. Hemodynamic stability was restored after surgical repair of the injured vessel, aggressive volume resuscitation and inotropic/vasopressor treatment. This case suggests that portable ultrasonography is an invaluable bedside tool which allows anesthesiologists to made reliable and prompt diagnosis of potentially fatal complications, such as perforation of great central vein due to inadvertent cannulation.

Keywords

catheterization, central venous; hemothorax; shock; ultrasonography;

1. Introduction

Central venous catheterization plays an important role in patients with end-stage renal failure undergoing temporal or long-term hemodialysis. Although in most procedures, central vascular access is successfully performed using landmark-based methods for catheterization, potentially lethal complications including arterial puncture, injury of great vessels, cardiac tamponade, and pneumothorax or hemothorax have been reported to occur in 6.2−10.7% of patients.¹ These complications require prompt diagnosis and proper intervention for survival. Bedside ultrasonography is a good tool for the evaluation of many critical conditions; particularly, more recent work has demonstrated the value of transthoracic echocardiography (TTE) in the immediate and accurate detection of hemothorax and pneumothorax.² In this report, we describe a patient who developed massive hemothorax following subclavian insertion of a hemodialysis catheter (HC), which was successfully detected by portable TTE.

2. Case Report

A 78-year-old woman weighing 51 kg and suffering from end-stage renal disease was scheduled to undergo a tunneled passage of a cuffed HC (PermCath™; Quinton Inc., Seattle, WA, USA) in the right subclavian vein for hemodialysis. She had many medical maladies including diabetes, hypertension, old cerebral ischemic infarction, and Child C liver cirrhosis with massive ascites. Panendoscopy revealed severe esophageal varices and gastric ulcer. Echocardiography demonstrated preservable left ventricular systolic function. Preoperative laboratory examination showed hemoglobin 8.4 g/dL, serum creatinine 11.1 mg/dL, and potassium 3.5 mmol/L.

On arrival at the operating room, her blood pressure was 176/64 mmHg and heart rate was 74 beats/ min. General anesthesia was induced with 5 mg of midazolam, 50 μg of fentanyl, and 60 mg of succinylcholine. After tracheal intubation, sevoflurane in a mixture of oxygen and air and atracurium were used for maintenance of anesthesia. Physiologic surveillance included noninvasive blood pressure, electrocardiography, pulse oximetry, capnometry, and direct radial artery pressure.

Making use of anatomic landmarks and pursuant to the Seldinger technique, the cardiovascular surgeon began the passage of an HC into the right subclavian vein. This was carried out with an 18-gauge introducer needle to penetrate the skin to a depth of 3−4 cm, through which a guidewire was passed. After making a small incision around the entrance of the guidewire with a scalpel, a 12F vessel dilator was passed over the guidewire to a length of about 7 cm and then withdrawn. The PermCath was inserted over the wire until free withdrawal of blood was obtained from both ports. After securing the catheter, an abrupt drop in blood pressure to 55/ 30 mmHg occurred. Hemodynamic support with dopamine and epinephrine was given, and aggressive fluid challenge was initiated immediately. However, the mean arterial blood pressure remained low, in the range of 35−40 mmHg, and heart rate was 70−80 beats/min. Gradual elevation of airway pressure, which coincided with diminished breath sounds at the right hemithorax, was noted. Meanwhile, endtidal CO₂ fell from 32 to 24 mmHg. Subsequent arterial blood gas analysis showed that hemoglobin concentration had decreased to 3 mg/dL. Because of her esophageal varices, transthoracic ultrasonography (MicroMAXX™; Sonosite Inc., Bothell, WA, USA) rather than transesophageal echocardiography (TEE) was performed to facilitate rapid differential diagnosis. The ultrasonic probe (MicroMAXX™, P17/ 1−5 MHz) was placed on the 11^th intercostal space at the right mid-axillary line and revealed a large anechoic area above the right hemidiaphragm, suggestive of extensive hemothorax. To further confirm the diagnosis and prevent the development of tension hemothorax, a right thoracostomy tube was inserted. Shortly, 3000 mL of fresh blood was directly drained off, and the patient’s condition became more hemodynamically unstable, indicating continuous active bleeding. The blood drainage was rapidly halted by clamping the thoracostomy tube; urgent lateral thoracotomy was contemplated to explore the nature and site of the active bleeding.

After opening the chest, a large amount of blood was noted in the thoracic cage, which was found to originate from a penetration wound at the superior vena cava. Surgical repair with 4-O prolene suture was performed; however, while the vascular repair was nearly completed, the patient suddenly developed severe bradycardia followed by cardiac arrest. The surgeon accelerated the vessel repair while open cardiac massage and epinephrine administration was underway. Fortunately, the heart rhythm resumed and blood pressure was restored and stabilized.

The estimated blood loss during the procedure was 8000 mL. A total of 8100 mL of blood products (3000 mL of packed red blood cells, 3000 mL of fresh frozen plasma, 1750 mL of whole blood, and 350 mL of platelets) was transfused during the anesthetic management. Follow-up arterial blood gas analysis revealed a hemoglobin level of 9.3 mg/dL. The patient was transferred to the ICU with arterial blood pressure of 115/60 mmHg and heart rate of 88 beats/min under 2.7 μg/kg/min of dopamine support. She regained clear consciousness the next day and was returned to the ordinary ward after a 7-day ICU stay.

3. Discussion

Central venous catheterization is an integral component of hemodialysis in uremic patients. Before the availability of real-time ultrasound guidance, central catheter insertion was performed pursuant to the percutaneous Seldinger technique based on anatomic landmarks with considerable success.³ However, a variety of immediate complications can occur at the time of HC placement, especially if it is performed through a right subclavian vein approach. Of the lifethreatening complications arising from inadvertent puncture of the central vein, arterial injury (10.7%), hemothorax (0.5−1%), pneumothorax (1%), hemomediastinum (0.6%), arrhythmia (0.2%) and pericardial tamponade (0.8%) stand out.⁴ As unexpected cardiovascular collapse is often the primary feature that signals the advent of a vascular accident, it is vital to make an appropriate interpretation and rapid differential diagnosis for specific intervention.

Our patient developed sudden profound hypotension after subclavian insertion of the HC, along with a drop in hemoglobin level, elevated airway pressure and decreased breath sounds on auscultation. Development of hemothorax, tension pneumothorax or pericardial tamponade, alone or in combination, gravely concerned us. Although chest radiography may be considered the gold standard for detection of pneumothorax, hemothorax, or cardiac tamponade with injection of contrast media through the central venous catheter,⁵ it is a time-consuming and cumbersome technique, particularly when patients are in the supine position. TEE is regarded as an excellent perioperative diagnostic tool for unearthing the culprit of unexplained shock because it is less invasive, safe, and capable of giving an immediate diagnosis.⁶ It is also helpful in guiding therapy in hemodynamically unstable patients in the operating room⁷ and ICU.⁶ Nevertheless, TEE was contraindicated in our patient because of her existing esophageal varices. Thus, portable TTE was used as a real-time imaging device for evaluating the critical disorder. TTE can help intensivists evaluate left ventricular function, volume status, and regional wall motion abnormalities and pericardial effusion in critically ill patients, so as to allow subsequent management.⁸ Recently, it has become an attractive diagnostic device for assessing pulmonary and extrapulmonary pathologies such as pneumothorax, hemothorax, pleural effusion, lung consolidation, pulmonary abscess and pulmonary embolism.⁹ In the emergent setting, bedside transthoracic ultrasonography for detecting hemothorax after chest trauma yields a sensitivity of 92% and a specificity of 100%.¹⁰

In our patient, placement of the ultrasound probe (MicroMAXX™, P17/1−5 MHz) at the right 11^th intercostal space revealed a large anechoic area above the right hemidiaphragm, which was recognized as a hyperechoic line just superior to the liver, indicating the formation of massive hemothorax. The volume of the effusive blood can be quantified by the transthoracic ultrasound approach using several formulas. A useful technique for clinical purposes is to measure the distance between the lung base and the posterior chest wall in the supine position; for example, a distance that is ≥ 50 mm is highly predictive of a fluid amount that is ≥ 500 mL.¹¹ For critical intervention, the nature and extensiveness of the hemothorax in consequence of HC placement should be rapidly sorted out through differential diagnosis from among venous perforation, puncture of the subclavian artery or pulmonary artery, internal mammary artery injury, or heart chamber perforation with pericardial tamponade. We found no evidence of cardiac tamponade from TTE examination. Following thoracotomy, perforation of the superior vena cava was identified as the culprit of the hemothorax.

Perforation of a great vessel occurs most often when the right subclavian vein approach is used, largely in consequence of forced insertion of the vessel dilator which is inadvertently pushed too far.¹² There is usually a false presumption that if the guidewire passes smoothly into the vein, it is able to successfully guide the dilator through the vessel.¹² However, the dilator is rather stiff, so its forceful advancement may perforate the vessel wall or even the cardiac chamber if the guidewire kinks.¹³ The use of excessive force to insert the dilator too deep might have been responsible for the complication in our patient because the length of insertion was nearly half the length of the dilator. Thus, it is imperative that excessive force is never used to push the dilator in the act of insertion, and the length of advancement of the dilator is as short as possible to yield an appropriate anchorage. Moreover, as the subclavian insertion of a HC is anatomically close to the great vessels or lung parenchyma, the insertion should be performed or strictly supervised by a senior or experienced physician whenever possible.

With the view of minimizing these life-threatening complications, an increasing number of studies have emphasized the value of transthoracic ultrasound not only in guiding regional nerve block but also in facilitating central venous access to prevent perforation of a great vessel.^14,15 The use of an ultrasound-guided approach can significantly improve the safety, success rate, and patient comfort by defining the vascular anatomy, showing related complications from prior attempts, and providing the direction of needle puncture.¹⁴ Reductions in the failure rate from 55% to 8% and in the complication rate from 41% to 4% have been reported with the use of ultrasound guidance in subclavian vein catheterization compared to the use of landmark-based techniques.¹⁵

In conclusion, iatrogenic perforation of the superior vena cava is a serious and potentially fatal complication that may occur after subclavian insertion of a HC. Physicians should be alert to the possible development of this complication throughout the procedure so that, should it occur, it can be identified early, a prompt diagnosis made, and appropriate management begun. Portable transthoracic ultrasonography is a readily available and reliable tool for timely detection and differential diagnosis in many critical situations, especially when TEE is not suitable because of severe esophageal pathology. Moreover, real-time ultrasound guidance of subclavian vein cannulation can minimize the complication rate and may become the standard approach for successful HC placement and monitoring for possible complications.