Selective brain hypothermia: feasibility and safety study of a novel method in five patients.

BACKGROUND/OBJECTIVE: Reduction of brain temperature remains the most common method of neuroprotection against ischemic injury employed during cardiac surgery. However, cooling delivered via the cardiopulmonary bypass circuit is brief and cooling the body core along with the brain has been associated with a variety of unwanted effects. This study investigated the feasibility and safety of a novel selective brain cooling approach to induce rapid, brain-targeted hypothermia independent of the cardiopulmonary bypass circuit. METHODS: This first-in-human feasibility study enrolled five adults undergoing aortic valve replacement with cardiopulmonary bypass support. During surgery, the NeuroSave system circulated chilled saline within the pharynx and upper esophagus. Brain and body core temperature were continuously monitored. Adverse effects, cardiopulmonary function, and device function were noted. RESULTS: Patient 1 received cooling fluid for an insignificant period, and Patients 2-5 successfully underwent the cooling procedure using the NeuroSave system for 56-89 minutes. Cooling fluid was 12°C for Patients 1-3, 6°C for Patient 4, and 2°C for Patient 5. There were no NeuroSave-related adverse events and no alterations in cardiopulmonary function during NeuroSave use. Brain temperature decreased by 3°C within 15 minutes and remained at least 3.5°C colder than the body core. During a brief episode of hypotension in one patient, the brain cooled an additional 4°C in 2 minutes, briefly reaching 27.4°C. CONCLUSION: The NeuroSave system can induce rapid brain-targeted hypothermia and simultaneously maintain a favorable body-brain temperature gradient, even during hypotension. Further studies are required to evaluate the function of the system during longer periods of use.

Effect of multiorgan donation after cardiac death retrieval on lung performance.

AIM: For donation after cardiac death (DCD) transplantation to achieve its full potential, multiorgan retrieval is desirable. Although there are several novel individual techniques recently described for DCD lung donation, they have not been evaluated or compared in a DCD multiorgan scenario. DESCRIPTION: This study describes (i) the technical aspects and (ii) early lung and abdominal organ performance of several combinations of DCD donor liver, kidney and lung retrieval techniques that would mimic common DCD clinical scenarios. EVALUATION: Lung oxygenation, urine production, bile production and biochemical measures were assessed as the outcome of a complex ex vivo lung, liver and kidney perfusion DCD model. CONCLUSION: Successful ex vivo multiorgan perfusion was possible following the three retrieval techniques tested, with excellent oxygenation over a 2-h assessment period, identical to prior studies where the lungs were tested alone. Multiorgan DCD retrieval, including lungs of good quality, is possible from a variety of clinical scenarios and should therefore be considered with all DCD retrieval opportunities.

A practical approach to clinical lung transplantation from a Maastricht Category III donor with cardiac death.

Although donation after cardiac death (DCD) has the potential to provide a novel source of organs for lung transplantation, even in a controlled DCD situation such as a Maastricht Category III donor (withdrawal of treatment), the limited time frame available after the declaration of death to initiate procurement and preservation remains challenging. Indeed, no publication has detailed the exact time frames and technique applicable for successful Maastricht Category III DCD lung procurement. In this patient report, withdrawal of life-support treatment and death certification was performed in the intensive care unit and the lungs were procured in an operating room 49 minutes after cardiac arrest and successfully transplanted (cold ischemia time <6 hours) into a severely ill recipient with primary pulmonary hypertension.

Evaluation of techniques for lung transplantation following donation after cardiac death.

BACKGROUND: Lung transplantation using "donation after cardiac death" donors is a potential means to alleviate the shortage of suitable donor lungs for transplantation, but the practicality and utility of the various possible techniques need to be clarified. METHODS: Using a dog model, we explored seven variations of standoff (ischemic) time (50 to 240 minutes), topical cooling (60 to 120 minutes), and flush cooling and cold storage (30 to 140 minutes) to mimic different human donor lung retrieval scenarios that can follow donation after cardiac death. The functional status of donation after cardiac death donor lungs was assessed initially with a 250 mL pulmonary arterial blood flush while ventilating with 100% oxygen and then on an ex-vivo perfusion rig for 120 minutes after retrieval. RESULTS: All lungs achieved an excellent pO2/FiO2 ratio ranging from 472 to 586 with stable pulmonary artery pressures and pulmonary vascular resistance and no net weight gain (952 +/- 221 g versus 1,006 +/- 235 g) during the 120-minute evaluation period. Initial blood flush correlated well with measured perfusion rig pO2 at 30 minutes (R2 = 0.63). CONCLUSIONS: This canine study suggests that lungs donated after cardiac death are reproducibly useable for transplantation with ischemic times of as long as 60 minutes. Although more study is needed, a blood flush evaluation is simple and may have a role as a secondary allograft assessment tool. The existing techniques of donor lung evaluation and preservation after donation following cardiac death thus appear both feasible and practical.