Judiann Miskulin

Extracorporeal Life Support for Severe Acute Respiratory Distress Syndrome in Adults

Objective:Severe acute respiratory distress syndrome (ARDS) is associated with a high level of mortality. Extracorporeal life support (ECLS) during severe ARDS maintains oxygen and carbon dioxide gas exchange while providing an optimal environment for recovery of pulmonary function. Since 1989, we have used a protocol-driven algorithm for treatment of severe ARDS, which includes the use of ECLS when standard therapy fails. The objective of this study was to evaluate our experience with ECLS in adult patients with severe ARDS with respect to mortality and morbidity. Methods:We reviewed our complete experience with ELCS in adults from January 1, 1989, through December 31, 2003. Severe ARDS was defined as acute onset pulmonary failure, with bilateral infiltrates on chest x-ray, and PaO2/fraction of inspired oxygen (FiO2) ratio ≤100 or A-aDO2 >600 mm Hg despite maximal ventilator settings. The indication for ECLS was acute severe ARDS unresponsive to optimal conventional treatment. The technique of ECLS included veno-venous or veno-arterial vascular access, lung “rest” at low FiO2 and inspiratory pressure, minimal anticoagulation, and optimization of systemic oxygen delivery. Results:During the study period, ECLS was used for 405 adult patients age 17 or older. Of these 405 patients, 255 were placed on ECLS for severe ARDS refractory to all other treatment. Sixty-seven percent were weaned off ECLS, and 52% survived to hospital discharge. Multivariate logistic regression analysis identified the following pre-ELCS variables as significant independent predictors of survival: (1) age (P = 0.01); (2) gender (P = 0.048); (3) pH ≤7.10 (P = 0.01); (4) PaO2/FiO2 ratio (P = 0.03); and (5) days of mechanical ventilation (P < 0.001). None of the patients who survived required permanent mechanical ventilation or supplemental oxygen therapy. Conclusion:Extracorporeal life support for severe ARDS in adults is a successful therapeutic option in those patients who do not respond to conventional mechanical ventilator strategies.

Nitric oxide releasing silicone rubbers with improved blood compatibility: preparation, characterization, and in vivo evaluation.

Nitric oxide (NO) releasing silicone rubbers (SR) are prepared via a three-step reaction scheme. A diamino triaminoalkyltrimethoxysilane crosslinker is used to vulcanize hydroxyl terminated polydimethylsiloxane (PDMS) in the presence of ambient moisture and a dibutyltin dilaurate catalyst so that the respective diamine triamine groups are covalently linked to the cured SR structure. These amine sites are then diazeniumdiolated, in situ, when the cured SR is reacted with NO at elevated pressure (80 psi). Although nitrite species are also formed during the NO addition reaction, in most cases the diazeniumdiolated polymer is the major product within the final SR matrix. Temperature appears to be the major driving force for the dissociation of the attached diazeniumdiolate moieties, whereas the presence of bulk water bathing the SR materials has only minimal effect on the observed NO release rate owing to the low water uptake of the SR matrices. The resulting SR films/coatings release NO at ambient or physiological temperature for up to 20 d with average fluxes of at least 4 x 10(10) mol x cm(-2) x min(-1) (coating thickness > or = 600 microm) over first 4 h, comparable to the NO fluxes observed from stimulated human endothelial cells. The NO loading and concomitant NO release flux of the SR material are readily adjustable by altering the diamine triamine loading and film/coating thickness. The new NO releasing SR materials are shown to exhibit improved thromboresistance in vivo, as demonstrated via reduced platelet activation on the surface of these polymers when used to coat the inner walls of SR tubings employed for extracorporeal circulation in a rabbit model.

Parathyroid adenomas versus four-gland hyperplasia as the cause of primary hyperparathyroidism in patients with prolonged lithium therapy.

Chronic lithium therapy in patients with affective psychiatric disorders has been implicated as the cause of hypercalcemia and primary hyperparathyroidism. Our objective was to evaluate whether primary hyperparathyroidism was caused by an adenoma or four-gland hyperplasia. The medical records of 15 patients with affective psychiatric disorders who were treated with chronic lithium therapy from 1982 to 1997, all of whom were operated on for primary hyperparathyroidism, were reviewed. Data on age, symptoms, duration of lithium therapy, pre- and postoperative calcium levels, and parathyroid hormone levels were collected. Parathyroid histology for each patient was independently and blindly reviewed. The mean age was 58 ± 10 years, the mean duration of lithium therapy 10.7 ± 6 years, and the mean preoperative calcium level 11.7 ± 0.5 mg/dl. All patients underwent bilateral neck exploration with selective resection of enlarged glands. Of the 15 patients, 14 (92%) had adenomas (11 single, 3 double), and 1 (8%) had four-gland hyperplasia. All patients were rendered eucalcemic, with a postoperative calcium level of 9.2 ± 0.5 mg/dl (p < 0.005). All patients resumed their lithium therapy, with 1 of 15 patients developing recurrent hyperparathyroidism 2 years following the first operation; this patient required reexploration, at which time an adenoma was resected. In our experience hyperparathyroidism in patients who have undergone prolonged therapy with lithium is associated with a high incidence of parathyroid adenomas versus four-gland hyperplasia. This suggests that lithium selectively stimulates growth of parathyroid adenomas in susceptible patients, who are best treated with adenoma excision rather than subtotal parathyroidectomy.

Is preoperative iodine 123 meta-iodobenzylguanidine scintigraphy routinely necessary before initial adrenalectomy for pheochromocytoma? ☆

BACKGROUND Iodine 123 meta-iodobenzylguanidine (MIBG) scintigraphy has been used in patients with clinical suspicion of pheochromocytoma to confirm the nature of an adrenal or extraadrenal mass or to identify occult disease. Additionally, it may be used to identify unsuspected bilaterality or metastases in the setting of a known unilateral adrenal mass before operation. We sought to determine the role of (123)I MIBG scintigraphy in this apparently routine preoperative setting. Our hypothesis was that (123)I MIBG would provide additional preoperative information that could modify operative intervention. METHODS All patients undergoing (123)I MIBG scintigraphy at our institution between 1992 and 2002 were identified. MIBG results, operative procedures and findings, and pathologic findings were retrospectively reviewed and compared. RESULTS The (123)I MIBG scintigraphy was performed in a total of 315 patients. Of these, 48 were patients with an initial biochemical diagnosis of pheochromocytoma and a unilateral adrenal mass. 47 of the 48 (98%) primary scans were positive for a single focus of activity concordant with anatomic imaging data from computed tomography or magnetic resonance imaging and operative findings. The (123)I MIBG did not reveal unsuspected metastatic or bilateral disease in any patient. CONCLUSION In this large series of patients undergoing (123)I MIBG scintigraphy, the test served only to confirm diagnostic impressions and corroborate anatomic imaging. The (123)I MIBG did not alter the operative management of any patient with a solitary adrenal lesion in the clinical context of biochemically-proven catecholamine excess.

Salvage of an unstable brain dead donor with prompt extracorporeal support

Maximizing the support of the marginal donor is an approach to optimizing the donor pool. Thirty-two percent of brain dead donors are hemodynamically unstable and 25% of donors under the age of 60 with traumatic brain injuries expire before organs can be procured (1, 2). When standard donor management protocols are insufficient to salvage a potential donor, aggressive attempts to save the organs can be considered. We present a case of an unstable brain dead donor who suffered premature cardiac death and the use of ECMO (extra-corporeal membrane oxygenation) perfusion in the successful salvage of organs for transplantation. Shortly after being declared brain dead, a 25-year-old patient became hypoxic and hemodynamically unstable. The patient’s family strongly desired organ donation. Despite hormonal replacement and three vasopressors, his mean arterial pressure (MAP) was less than 45 mm Hg. The situation was reviewed with the family, who gave consent for ECMO. The ECMO team was called for an emergent cannulation. The patient was placed on venous-arterial ECMO via cannula placement in the common femoral artery, the internal jugular vein, and the common femoral vein. The patient had a significant improvement in hemodynamics and resumed making urine (MAP 60 to 75). Approximately 75 min later and for unclear reasons, the patient had a cardiac arrest. The MAP was maintained at 53 via ECMO support following cessation of cardiac activity. The patient was transported to the operating room. ECMO flow was not interrupted during this transport. Shortly after arriving into the operating room, cold University of Wisconsin solution was infused through the ECMO circuit. The femoral venous cannula was cut and allowed to drain into a waste bucket. The abdomen was opened and cold slush was poured into the abdominal cavity. The perfusate return soon cleared and the kidneys were procured in the standard fashion. The kidneys were placed on pulsatile pump perfusion. Both kidneys were transplanted and functioned immediately. At our center, we have had success with a protocol using extracorporeal support for NHBDs (non-heart beating donors) (3). In our experience with NHBD, balloon aortic occlusion and a mean ECMO flow of 3.0 L/minute provides physiologic flow to the intra-abdominal organs. Failure of physiologic support to prevent early cardiac death was the second most frequent potentially remediable causes of procurement failure (4). Many potential donors who are unstable are not referred to the local organ procurement organization. In addition, patients who have been hemodynamically tenuous are frequently only kidney donors and the other organs are not procured. In this case, the use of ECMO salvaged the kidneys for donation. In addition, the circuit provided an expeditious means to perfuse with cold University of Wisconsin solution. Using ECMO to optimize brain dead donors is a novel strategy to increase the number of donors and the yield of organs per donor. Michael J. Englesbe Derek Woodrum Meelie Debroy Richard Chenault William Miller Judiann Miskulin Fresca Swaniker John C. Magee Juan D. Arenas Jeffery D. Punch Randall S. Sung Department of Surgery Division of Transplant Surgery and Surgical Critical Care University of Michigan Health System Ann Arbor, Michigan

Developing a small animal model of extracorporeal circulation

To identify nonthrombogenic devices to be used in extracorporeal circulation (ECC), an efficient, small animal model is required. Initially, a venovenous (VV) model in rabbits was designed for this purpose and was a good representation of ECC. Technical difficulties in the VV model led to the development of a more simplistic arteriovenous (AV) model. Anesthetized, tracheotomized, 3-kg rabbits were used for both models. Circuits were constructed of PVC tubing. The VV model used 8-Fr umbilical artery catheters for both drainage and reinfusion, and the AV model used a 14-GA angiocatheter for carotid artery access and a 10-Fr thoracic catheter for venous access. The AV model included a chamber to mimic oxygenator or filter modeling. Hourly measurements included blood gases, platelet counts, and fibrinogen levels for the 4-hour studies. The VV ECC groups demonstrated platelet consumption like that seen in the clinical arena. The AV model demonstrated the same with or without additional surface area within the chamber. The AV model was deemed to be superior due to its simplicity, ability for filter modeling, and decrease in intensive monitoring. However, both models are excellent designs for nonthrombogenic surface testing.

Metastatic Papillary Thyroid Carcinoma Causing Hand Weakness

433 A63-YEAR-OLD-WOMAN had right hand weakness accompanying a right neck mass. Examination revealed a large right thyroid mass, bilateral cervical lymphadenopathy, and weakness of the right intrinsic hand muscles and adductor pollicis. Magnetic resonance imaging (MRI) (Fig. 1) revealed a 6.5-cm thyroid mass (A) and a destructive lesion of C7 and T1 with spinal cord compression (B). Thyroid fine-needle aspiration (FNA) suggested papillary thyroid cancer. Serum thyroglobulin was 2266 ng/mL. On preoperative angiography, the primary tumor (A) was supplied by the right inferior thyroid artery (Fig. 2) while the spinal metastasis (B) was served by the left supreme intercostal artery which was em-