Monday, August 30, 2010

Cryospray Against Airway Tumors Leads to Unexpected Complications

Spray cryotherapy with liquid nitrogen has been used effectively for ablating esophageal tumors. Some facilities even perform the technique in an outpatient setting under sedation. However, spray cryotherapy for treating advanced airway lesions—when other treatment options are limited—is more recent, and few reports of its effectiveness have been published (J Thorac Cardiovasc Surg 2010;139:781-782).

To assess their efforts to date, thoracic anesthesiologists at Memorial Sloan-Kettering Cancer Center in New York City reviewed 24 spray cryotherapy procedures in 22 patients; all treatments involved airway-obstructing tumors. Ten of the patients (45%) experienced unexpected and serious respiratory or cardiovascular events; of these, three required reintubation and mechanical ventilation overnight. One patient suffered cardiac arrest and died in the operating room (Table).

Table. Complications From Cryospray
(% of procedures)
Pneumothorax2 (2.8)
Hypoxemia5 (20.8)
Reintubation3 (12.5)
ST-segment changes3 (12.5)
Bradycardia6 (25)
Tachycardia3 (12.5)
Hypotension7 (29)
Death1 (0.04)

“We did not expect to see such an incidence of cardiac complications during this procedure,” said Alessia Pedoto, MD, lead author of the study presented at the 2010 annual meeting of the Society of Cardiovascular Anesthesiologists (abstract SCA41), in New Orleans.

The spray cryotherapy technique delivered liquid nitrogen by catheter through an endoscope at 2 to 4 psi at –196 C, causing rapid freezing and thawing of tissue—resulting in cell death and hemostasis (Figures 1 and 2). A minimum of three cycles of five seconds each was administered to each patient, with a complete visual thaw between each cycle. All patients underwent general anesthesia for combined rigid and flexible bronchoscopy.

Among the 24 procedures, hypoxemia developed in five (20.8%); ST-segment changes developed in three (12.5%); bradycardia in six (25%); and hypotension in seven (29%). More than one complication occurred per procedure.

“Bleeding and pneumothorax have been reported in very small series and we had two cases of pneumothorax we thought were related to the use of jet ventilation with cryospray,” Dr. Pedoto told Anesthesiology News. “We speculate that the use of cold liquid nitrogen is associated with an increase in airway pressure when the spray is used, affecting the heart and the conduction system,” she said.

According to the researchers, spray cryotherapy is a novel technique that can be used to re-establish airway patency in patients with symptomatic airway tumors. The advantages it might offer over airway laser therapy include no fire hazard and improved hemostasis. They said that further study is needed for better selection and improved safety of patients.

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