Jacek B. Cywinski

Relationship between intraoperative mean arterial pressure and clinical outcomes after noncardiac surgery: toward an empirical definition of hypotension.

Background:Intraoperative hypotension may contribute to postoperative acute kidney injury (AKI) and myocardial injury, but what blood pressures are unsafe is unclear. The authors evaluated the association between the intraoperative mean arterial pressure (MAP) and the risk of AKI and myocardial injury. Methods:The authors obtained perioperative data for 33,330 noncardiac surgeries at the Cleveland Clinic, Ohio. The authors evaluated the association between intraoperative MAP from less than 55 to 75 mmHg and postoperative AKI and myocardial injury to determine the threshold of MAP where risk is increased. The authors then evaluated the association between the duration below this threshold and their outcomes adjusting for potential confounding variables. Results:AKI and myocardial injury developed in 2,478 (7.4%) and 770 (2.3%) surgeries, respectively. The MAP threshold where the risk for both outcomes increased was less than 55 mmHg. Compared with never developing a MAP less than 55 mmHg, those with a MAP less than 55 mmHg for 1–5, 6–10, 11–20, and more than 20 min had graded increases in their risk of the two outcomes (AKI: 1.18 [95% CI, 1.06–1.31], 1.19 [1.03–1.39], 1.32 [1.11–1.56], and 1.51 [1.24–1.84], respectively; myocardial injury 1.30 [1.06–1.5], 1.47 [1.13–1.93], 1.79 [1.33–2.39], and 1.82 [1.31–2.55], respectively]. Conclusions:Even short durations of an intraoperative MAP less than 55 mmHg are associated with AKI and myocardial injury. Randomized trials are required to determine whether outcomes improve with interventions that maintain an intraoperative MAP of at least 55 mmHg.

Cumulative risk of cardiovascular events after orthotopic liver transplantation

As survival after orthotopic liver transplantation (OLT) improves, cardiovascular (CV) disease has emerged as the leading cause of non–graft‐related deaths. The aims of our study were to determine the cumulative risk of CV events after OLT and to analyze predictive risk factors for those experiencing a CV event after OLT. We identified all adult patients who underwent OLT at our institution for end‐stage liver disease between October 1996 and July 2008. The cumulative risk of CV events after OLT was analyzed with the Kaplan‐Meier method. Multivariate logistic regression analysis was used to identify factors independently associated with CV events after OLT. In all, 775 patients were included in our study cohort (mean age of 53.3 years, female proportion = 44%, Caucasian proportion = 84%, median follow‐up = 40 months). The most common indications for OLT were hepatitis C virus (33.2%), alcohol (14.5%), and cryptogenic cirrhosis (12.7%). Eighty‐three patients suffered 1 or more CV events after OLT. Posttransplant metabolic syndrome was more prevalent in patients with CV events versus patients with no CV events (61.4% versus 34.1%, P < 0.001). According to a multivariate analysis, independent predictors of CV events were an older age at transplantation [odds ratio (OR) = 1.2, addition of 95% confidence interval (CI) = 1.1‐1.3, P = 0.006], male sex (OR = 2.0, 95% CI = 1.2‐3.3, P = 0.01), posttransplant diabetes (OR = 2.0, 95% CI = 1.3‐3.3, P = 0.003), posttransplant hypertension (OR = 1.8, 95% CI = 1.1‐3.0, P = 0.02), and mycophenolate mofetil (OR = 2.0, 95% CI = 1.3‐3.2, P = 0.003). Among post‐OLT patients, the cumulative risk at 5 years of 13.5%, respectively. In conclusion, cardiac complications after liver transplantation are common (Approximately 10% of patients experience 1 or move cv events). Patients with posttransplant hypertension and diabetes, which are modifiable risk factors, are approximately twice as likely to experience a CV event. Liver Transpl 18:370–375, 2012.

Comparable graft and patient survival in lean and obese liver transplant recipients

Obesity is among the great health problems facing Americans today. More than 32% of the US population is considered obese on the basis of a body mass index (BMI) exceeding 30 kg/m2. Obesity increases the risk for numerous perioperative complications, but how obesity affects the outcome of liver transplantation remains unclear. We compared graft/patient survival after orthotopic liver transplantation performed at the Cleveland Clinic between April 2005 and June 2011 in 2 groups: obese patients with a BMI ≥ 38 kg/m2 and lean patients with a BMI between 20 and 26 kg/m2. We included 47 obese patients and 183 lean patients, whose demographics and baseline characteristics were well balanced after weighting with the inverse propensity score. After we controlled for observed confounding, no significant differences were observed in graft/patient survival between obese and lean patients (P = 0.30). The estimated hazard ratio for obese patients to experience graft failure or death was 1.19 [95% confidence interval (CI) = 0.85‐1.67]. There were 134 patients who had follow‐up for more than 3 years, and they included 27 obese patients and 107 lean patients. Within this subset, the odds of having metabolic syndrome were significantly greater for obese patients (46%) versus lean patients (21%; odds ratio = 4.76, 99.5% CI = 1.66‐13.7, P < 0.001). However, no significant association between obesity and any other long‐term adverse outcomes was found. In conclusion, this study shows that transplant outcomes were comparable for lean and obese recipients. We thus recommend that even morbid obesity per se should not exclude patients from consideration for transplantation. Liver Transpl 19:907‐915, 2013.

The effect of epidural vs intravenous analgesia for posterior spinal fusion surgery

Background : The study objective was to compare epidural vs intravenous postoperative analgesia in posterior spinal fusion surgery patients.

A comparison of postoperative pain control in patients after right lobe donor hepatectomy and major hepatic resection for tumor

After initiating a living donor liver transplant program at our institution, we observed that donor patients experienced significant postoperative pain despite the use of thoracic patient-controlled epidural analgesia (PCEA) infusion catheters. We retrospectively compared patients who underwent right lobe donor hepatectomy (RLDH, n = 15) with patients who had undergone major hepatic resection for tumor (MHRT, n = 15) to elucidate the cause for this observation. All patients had preoperative thoracic epidural catheters placed, and both groups had similar surgical exposure. Demographic information, intraoperative variables, intensity of postoperative pain by visual analog pain score (VAPS), side effects, total number of requested and delivered PCEA doses, and the total amount of bupivacaine (mg) and volume (mL) of PCEA solution administered through 48 h postoperatively were collected and analyzed. The RLDH group had a significantly longer surgical duration than did the MHRT group. The RLDH group patients had higher postoperative pain scores (P = 0.034), and were 2.76 (1.12–6.82, 95% CI) times more likely to have pain than those patients in the MHRT group. There was no significant difference between patient groups for the amount of bupivacaine and volume of PCEA solution administered. These observations may be explained, in part, by the longer duration of surgery in the RLDH group. The possible role of preemptive analgesia via PCEA infusion and better perioperative teaching of PCEA use are discussed; these may lead to improved early postoperative pain control in RLDH patients.

Spinal Cord Stimulation for Visceral Pain From Chronic Pancreatitis

Background and Objectives:  Spinal cord stimulation (SCS) may reduce pain scores and improve function in patients with various chronic abdominal pain syndromes including chronic pancreatitis. Here described is a large clinical experience in SCS for severe chronic pancreatitis.

Prediction of intraoperative transfusion requirements during orthotopic liver transplantation and the influence on postoperative patient survival

BACKGROUND:Predicting blood product transfusion requirements during orthotopic liver transplantation (OLT) remains difficult. Our primary aim in this study was to determine which patient variables best predict recipient risk for large blood transfusion requirements during OLT. The secondary aim was to determine whether the amount of blood products transfused during OLT impacted patient survival. METHODS:Eight hundred four primary adult OLTs performed during a 9-year period were retrospectively analyzed, and predictive models were developed for blood product usage, usage >20 and usage >30 units of red blood cells (RBCs) plus cell salvage (CS). For survival analysis, potential predictors included all blood products administered during OLT. RESULTS:For analyses of RBC + CS usage, we used several statistical techniques: regression analysis, logistic regression, and classification and regression tree analysis. Several preoperative factors were highly statistically significant predictors of intraoperative blood product usage in each of the analyses, namely lower platelet count and higher Model for End-Stage Liver Disease Score or one or more of its components (creatinine, total bilirubin, international normalized ratio). Despite these highly significant associations, the models were unable to predict reliably that patients might require the largest amount of blood products during OLT. For example, the classification and regression tree analyses were able to predict only 32% and 11% of patients requiring >20 and >30 units of RBC + CS, respectively. Survival analysis demonstrated poorer survival among patients receiving larger amounts of RBC + CS during OLT. CONCLUSION:Prediction of intraoperative blood product requirements based on preoperatively available variables is unreliable; however, there is a strong measurable association between transfusion and postoperative mortality.

THE EFFECT OF DOPAMINE ON RENAL FUNCTION IN SOLITARY PARTIAL NEPHRECTOMY SURGERY

PURPOSE Dopamine continues to be used for preventing and treating acute renal failure. We determined the effects of dopamine on postoperative renal function in patients with a solitary kidney undergoing partial nephrectomy. MATERIALS AND METHODS We performed a prospective randomized controlled study at a tertiary care referral center involving 24 patients with a solitary kidney undergoing partial nephrectomy secondary to malignancy. Patients were randomized to receive dopamine (11) [corrected] or no dopamine (13) [corrected]. Intraoperatively those assigned to the dopamine group received a 3 microg./kg. per minute dopamine infusion. Patients in each group received an adequate amount of fluid to maintain good urine production, systemic blood pressure and central venous pressure. Serum electrolytes, blood urea nitrogen, creatinine, serum and urine osmolality, and urine output were measured at baseline, intraoperatively and through postoperative day 4. Preoperatively and postoperatively renal blood flow and the glomerular filtration rate were measured. RESULTS In the 2 groups blood urea nitrogen and serum creatinine increased postoperatively. Although the degree of this increase showed a trend to be lower in the dopamine group, the difference did not reach statistical significance. There was no difference in renal blood flow or the glomerular filtration rate in the treatment groups. CONCLUSIONS Administering dopamine to patients with a solitary kidney undergoing partial nephrectomy provided no renoprotective effect.

Association between donor‐recipient serum sodium differences and orthotopic liver transplant graft function

Previous studies have shown that donor hypernatremia and possibly recipient hyponatremia negatively impact graft function after orthotopic liver transplant (OLT). The purpose of this retrospective investigation was to determine whether measured differences in serum sodium values between cadaveric donors and OLT recipients (ΔNa+) influence immediate postoperative allograft function and short‐term patient outcomes. Two hundred and fifty patients that underwent OLT from January 2001 to December 2005 were included in this study. The ΔNa+ for each donor recipient pair was correlated with standard postoperative liver function tests as well as recipient length of intensive care unit stay (LOICUS), length of hospital stay (LOHS) and recipient survival. The relationship between donor hypernatremia (serum sodium ≥ 155 mEq/mL), recipient hyponatremia (serum sodium level ≤ 130 mEq/mL), and postoperative outcomes were analyzed as well. Adjustments were made for baseline potential confounders, including model for end‐stage liver disease (MELD) score, preservation solution used (HTK vs. UW), recipient and donor demographics and cold ischemia time (CIT). ΔNa+ as well as donor hypernatremia and recipient hyponatremia were not found to be associated with immediate postoperative allograft function, intraoperative blood product usage, LOICUS, LOHS or short‐term patient survival. However, both the preoperative MELD score and HTK preservation solution used were significantly associated with several patient outcomes. A higher MELD score was associated with both increased red blood cell (RBC) (P < 0.001) and fresh frozen plasma (FFP) usage (P = 0.002), elevated postoperative total bilirubin levels (P < 0.001), increased LOHS (P = 0.04), and a higher 30‐day post transplant mortality (P = 0.02). The use of HTK preservation solution was associated with higher mean postoperative aspartate aminotransferase levels (P = 0.02) and decreased mean RBC (P < 0.001) and FFP usage (P = 0.009) compared to UW preservation solution use. Liver Transpl 14:59–65, 2008.

Predictors of Prolonged Postoperative Endotracheal Intubation in Patients Undergoing Thoracotomy for Lung Resection

OBJECTIVE The aim of this study was to identify predictors of delayed endotracheal extubation defined as the need for postoperative ventilatory support after open thoracotomy for lung resection. DESIGN An observational cohort investigation. SETTING A tertiary referral center. PARTICIPANTS The study population consisted of 2,068 patients who had open thoracotomy for pneumonectomy, lobectomy, or segmental lung resection between January 1996 and December 2005. INTERVENTIONS Not applicable. MEASUREMENTS AND MAIN RESULTS Preoperative and intraoperative variables were collected concurrently with the patients care. Risk factors were identified using logistic regression with stepwise variable selection procedure on 1,000 bootstrap resamples, and a bagging algorithm was used to summarize the results. Intraoperative red blood cell transfusion, higher preoperative serum creatinine level, absence of a thoracic epidural catheter, more extensive surgical resection, and lower preoperative FEV(1) were associated with an increased risk of delayed extubation after lung resection. CONCLUSION Most predictors of delayed postoperative extubation (ie, red blood cell transfusion, higher preoperative serum creatinine, lower preoperative FEV(1), and more extensive lung resection) are difficult to modify in the perioperative period and probably represent greater severity of underlying lung disease and more advanced comorbid conditions. However, thoracic epidural anesthesia and analgesia is a modifiable factor that was associated with reduced odds for postoperative ventilatory support. Thus, the use of epidural analgesia may reduce the need for post-thoracotomy mechanical ventilation.