Timothy S. Shine

Laparoscopic Placement of Ventriculoperitoneal Shunts: Preliminary Report

We used a laparoscopic technique for the percutaneous placement of the peritoneal end of cerebrospinal fluid shunts in adult patients with obstructive or normal-pressure hydrocephalus. Concurrent with the initial cranial part of the procedure, pneumoperitoneum is established in a routine fashion, and a video-laparoscope and grasping forceps are inserted into the peritoneal cavity. With use of a pacemaker introducer kit, the peritoneal catheter is placed percutaneously under direct laparoscopic vision through a small upper abdominal incision into the peritoneal cavity. At the completion of the procedure, the patency of the assembled shunt system can be verified by observing free flow of cerebrospinal fluid from the catheter tip as the valve is being pumped. We found that this technique is particularly useful in technically challenging cases--for example, those involving obese patients and those who have undergone multiple abdominal operations. No complications associated with the technique were encountered.

Motor and somatosensory evoked potentials: their role in predicting spinal cord ischemia in patients undergoing thoracoabdominal aortic aneurysm repair with regional lumbar epidural cooling.

Background:Paraplegia is a devastating complication for patients undergoing repair of thoracoabdominal aortic aneurysms. A monitor to detect spinal cord ischemia is necessary if anesthesiologists are to intervene to protect the spinal cord during aortic aneurysm clamping. Methods:The medical records of 60 patients who underwent thoracoabdominal aortic aneurysm repair with regional lumbar epidural cooling with evoked potential monitoring were reviewed. The authors analyzed latency and amplitude of motor evoked potentials, somatosensory evoked potentials, and H reflexes before cooling and clamping, after cooling and before clamping, during clamping, and after release of aortic cross clamp. Results:Twenty minutes after the aortic cross clamp was placed, motor evoked potentials had 88% sensitivity and 65% specificity in predicting spinal cord ischemia. The negative predictive value of motor evoked potentials at 20 min after aortic cross clamping was 96%. Conclusions:Rapid loss of motor evoked potentials or H reflexes after application of the aortic cross clamp identifies a subgroup of patients who are at high risk of developing spinal cord ischemia and in whom aggressive anesthetic and surgical interventions may be justified.

Is a mandatory intensive care unit stay needed after liver transplantation? Feasibility of fast‐tracking to the surgical ward after liver transplantation

The continuation of hemodynamic, respiratory, and metabolic support for a variable period after liver transplantation (LT) in the intensive care unit (ICU) is considered routine by many transplant programs. However, some LT recipients may be liberated from mechanical ventilation shortly after the discontinuation of anesthesia. These patients might be appropriately discharged from the postanesthesia care unit (PACU) to the surgical ward and bypass the ICU entirely. In 2002, our program started a fast‐tracking program: select LT recipients are transferred from the operating room to the PACU for recovery and tracheal extubation with a subsequent transfer to the ward, and the ICU stay is completely eliminated. Between January 1, 2003 and December 31, 2007, 1045 patients underwent LT at our transplant program; 175 patients were excluded from the study. Five hundred twenty‐three of the remaining 870 patients (60.10%) were fast‐tracked to the surgical ward, and 347 (39.90%) were admitted to the ICU after LT. The failure rate after fast‐tracking to the surgical ward was 1.90%. The groups were significantly different with respect to the recipient age, the raw Model for End‐Stage Liver Disease (MELD) score at the time of LT, the recipient body mass index (BMI), the retransplantation status, the operative time, the warm ischemia time, and the intraoperative transfusion requirements. A multivariate logistic regression analysis revealed that the raw MELD score at the time of LT, the operative time, the intraoperative transfusion requirements, the recipient age, the recipient BMI, and the absence of hepatocellular cancer/cholangiocarcinoma were significant predictors of ICU admission. In conclusion, we are reporting the largest single‐center experience demonstrating the feasibility of bypassing an ICU stay after LT. Liver Transpl 18:361–369, 2012.

Sodium nitroprusside decreases spinal cord perfusion pressure during descending thoracic aortic cross-clamping in the dog

Paraplegia is a devastating complication of surgery on the descending thoracic aorta. During surgical repair, the aorta is cross-clamped, and nitroprusside is often used to treat arterial hypertension that can occur above the cross-clamp. Twenty-one dogs were studied to determine the effects of nitroprusside on intraspinal pressures, mean aortic pressures below the cross-clamp, and spinal cord perfusion pressure. Perfusion pressure in spinal radicular arteries originating below the aortic cross-clamp was estimated as the distal aortic pressure minus intraspinal pressure. Nitroprusside was used to return the mean arterial pressure above the cross-clamp to values similar to the pre-cross-clamp levels in 7 dogs. Fourteen animals did not receive sodium nitroprusside. Aortic cross-clamping resulted in small but significant increases in intraspinal pressure (4.3 +/- 0.8 to 7.5 +/- 0.9 mm Hg in non-nitroprusside-treated dogs, and 3.4 +/- 1.0 to 5.6 +/- 1.5 mm Hg in the nitroprusside group before nitroprusside). Nitroprusside caused a further increase in intraspinal pressure (5.6 +/- 1.5 to 8.3 +/- 2.2 mm Hg) and a decrease in aortic pressure below the cross-clamp (26 +/- 5 to 18 +/- 4 mm Hg). The increase in intraspinal pressure and the decrease in aortic pressure below the cross-clamp after nitroprusside resulted in a decrease in spinal cord perfusion pressure from 19 +/- 5 mm Hg to 11 +/- 4 mm Hg. Because nitroprusside decreases spinal cord perfusion pressure and may increase the risk of spinal cord ischemia, the avoidance of large doses of nitroprusside to arbitrarily return mean arterial pressure above the cross-clamp to pre-cross-clamp levels is recommended.

Importance of perioperative blood glucose management in cardiac surgical patients.

Tight blood glucose control has become a therapeutic goal for anesthetic management of patients undergoing cardiovascular surgery. We discuss the evidence for a link between blood glucose levels and rates of morbidity and mortality in cardiac surgical patients in the intensive care unit. Hyperglycemia per se has been associated with higher rates of deep wound infection, neurologic, renal, and cardiac complications following surgery, as well as longer intensive care unit stay. We review the specifics of glucose management in patients undergoing cardiac surgery and hypothermic cardiopulmonary bypass, including the role that insulin may play in regulating blood glucose levels intraoperatively and the relationship between insulin and outcome.

Avoiding Stay in the Intensive Care Unit After Liver Transplantation: A Score to Assign Location of Care

Select liver transplantation (LT) recipients in our program are transferred from operating room to postanesthesia care unit for recovery and extubation with transfer to the ward, completely eliminating an intensive care unit (ICU) stay. Developing a reliable method to determine patients suitable for fast‐tracking would be of practical benefit to centers considering this practice. The aim of this study was to create a fast‐tracking probability score that could be used to predict successful assignment of care location after LT. Recipient, donor and operative characteristics were assessed for independent association with successful fast‐tracking to create a probability score. Of the 1296 LT recipients who met inclusion criteria, 704 (54.3%) were successfully fast‐tracked and 592 (45.7%) were directly admitted to the ICU after LT. Based on nine readily available variables at the time of LT, we created a scoring system that classified patients according to the likelihood of being successfully fast‐tracked to the surgical ward, with an area under the curve (AUC) of 0.790 (95% CI: 0.765–0.816). This score was validated in an independent group of 372 LT with similar AUC. We describe a score that can be used to predict successful fast‐tracking immediately after LT using readily available clinical variables.

ANESTHESIA FOR COMBINED CARDIAC SURGERY AND LIVER TRANSPLANT

OBJECTIVE To describe aspects of anesthesia for combined cardiac surgery and orthotopic liver transplant (OLT). DESIGN Retrospective case series. SETTING Hospital with cardiac surgery and liver transplant programs. PARTICIPANTS Nine patients between September 1998 and July 2006. INTERVENTION Combined cardiac surgery and OLT. MEASUREMENT AND MAIN RESULTS Demographic and outcome data were recorded for each patient. Multiple intraoperative parameters were collected at baseline, after induction of anesthesia, after cardiac surgery, and after OLT. Five patients underwent combined OLT and coronary artery bypass graft (CABG) surgery. Four patients underwent combined OLT and aortic valve replacement (AVR) to relieve aortic stenosis. One of these 4 patients also had a saphenous vein graft to the left anterior descending artery. The CABG/OLT patients had hypertension, diabetes, or both, and multiple coronary arteries were affected although ejection fraction was preserved. The 1 death in this group was unrelated to a coronary event. The AVR/OLT patients had aortic stenosis that met American Heart Association guidelines for AVR. One death, within 24 hours of surgery, was associated with severe pulmonary artery hypertension. The median transfusion volumes were 12 units of packed red blood cells, 22 units of fresh frozen plasma, and 30 units of platelets. Three of the 9 patients required renal replacement therapy postoperatively. The median duration of intubation was 2 days, and length of stay in the intensive care unit was 5.5 days. CONCLUSION Combined cardiac and OLT surgery is complex and serious morbidity occurs, but successful outcomes are attainable.

Arterial Blood Pressure System Modeling and Signal Analysis

An approach to modeling and signal processing of the human heart is presented. First the anatomy of the heart is described and the anatomical functions performed are outlined. A preliminary model of the cardio-systemic circuit system is described. The aim is to further refine the model to correlate to measured responses and characterization of those responses. The APB signal analysis method is quantified and empirical examples are provided and analyzed.

Unexplained and prolonged perioperative hypotension after orthotopic liver transplantation: Undiagnosed systemic mastocytosis

Arterial vasodilation is common in end‐stage liver disease, and systemic hypotension often may develop, despite an increase in cardiac output. During the preparation for and the performance of orthotopic liver transplantation, expected and transient hypotension may be caused by induction agents, anesthetic agents, liver mobilization, or venous clamping. A mild decrease of the already low systemic vascular resistance is often observed, and intermittent use of short‐acting agents for vasopressor support is not uncommon. In this report, we describe a patient with unexpected and prolonged hypotension due to vasodilation during and after orthotopic liver transplantation. The preoperative end‐stage liver disease evaluation, intraoperative events, and intensive care unit course were reviewed, and no cause for the vasodilation and prolonged hypotension was evident. The explant pathology report was later available and showed systemic mastocytosis. We hypothesize that the unexpected hypotension and vasodilation were caused by mast cell degranulation and its systemic effects on arterial tone. Liver Transpl 15:701–708, 2009.

Use of continuous paravertebral analgesia to facilitate neurologic assessment and enhance recovery after thoracoabdominal aortic aneurysm repair.

UNLABELLED Neurologic assessment after thoracic aortic aneurysm repair is important for detecting and treating late onset paraplegia. Traditional methods of pain control, such as patient-controlled IV analgesia and epidural analgesia, may interfere with neurologic assessment. We present a case of a patient who received continuous thoracic paravertebral analgesia that provided excellent analgesia while preserving the ability to monitor neurologic function. IMPLICATIONS We provided postoperative continuous paravertebral analgesia in a patient after thoracoabdominal aneurysm repair requiring postoperative neurologic assessment. Paravertebral analgesia provides unilateral analgesia with fewer neurologic and hemodynamic side effects than central neuraxial blockade and should be considered for management of patients undergoing thoracic aortic aneurysm repair.