Postoperative Laboratory Values Research Articles

A Prospective Study of Risk Factors for Nephrolithiasis After Roux-en-Y Gastric Bypass Surgery

Roux-en-Y gastric bypass surgery has become an increasingly common form of weight management. Early retrospective reviews have suggested that new onset nephrolithiasis develops in some patients after undergoing Roux-en-Y gastric bypass. We present a prospective longitudinal study to assess risk factors for nephrolithiasis after Roux-en-Y gastric bypass. A total of 45 morbidly obese patients scheduled to undergo Roux-en-Y gastric bypass surgery were enrolled in this prospective study between November 2006 and November 2007. Exclusion criteria included history of nephrolithiasis or inflammatory bowel disease. Serum uric acid, parathyroid hormone, calcium, albumin, and creatinine and 24-hour urine collections were obtained within 6 months before Roux-en-Y gastric bypass, and at 6 to 12 months postoperatively. A Wilcoxon signed-rank test was used to compare preoperative and postoperative serum laboratory values and 24-hour urine values. McNemar's test was used to determine if the percent of abnormal values underwent a statistically significant change after Roux-en-Y gastric bypass. For both statistical methods a p value was calculated for the change in each variable with p <0.05 considered statistically significant. Statistically significant changes included increased urinary oxalate and calcium oxalate supersaturation, and decreased urinary citrate and total urinary volume postoperatively. A statistically significant percentage of patients exhibited decreased urinary calcium, while a statistically significant percentage of patients experienced increased urinary oxalate and calcium oxalate supersaturation. Our prospective study demonstrated multiple factors that increase the relative risk of nephrolithiasis after Roux-en-Y gastric bypass. These changes may make stone formation after Roux-en-Y gastric bypass increasingly likely and pose an ongoing challenge in the realm of urology.

Appreciation Of Osteoporosis Among Men With Hyperparathyroidism

To define the scope of bone disease among men referred for parathyroidectomy and to document bone density screening trends in this high-risk population. Clinical data were analyzed from a prospectively maintained database of 1000 patients undergoing parathyroidectomy for sporadic primary hyperparathyroidism at the Cleveland Clinic between 2000 and 2006. Information collected included demographics, reason for referral, body mass index, intraoperative findings, preoperative and postoperative laboratory values (serum calcium, phosphorus, parathyroid hormone, 25-hydroxyvitamin D, and 24-hour urinary calcium excretion), and preoperative and postoperative dual-energy x-ray absorptiometry (DXA) findings. Of the 1000 patients, 243 (24%) were men. As with women, bone health-related issues were the most common reason for referral (32%). In 2000, only 12% of men had preoperative DXA scans; this rose to 42% by 2005. The frequency of prereferral DXA screening increased throughout the study, but even by 2006, referring physicians did not screen most of their male patients. In 2000, the prevalence of bone disease (osteoporosis or osteopenia) in men was 8%, but with improved screening, this increased to 26%, approaching the 34% rate in women. Preoperative and postoperative levels of calcium, parathyroid hormone, phosphorus, 24-hour urinary calcium, and 25-hydroxyvitamin D were the same among men with and without bone disease. Analysis of postoperative DXA scans revealed that gains in postparathyroidectomy bone density were significantly greater in men than in women at all anatomic testing sites. In men, lowest T scores improved by a mean +/- SEM of +0.35 +/- 0.09 compared with +0.098 +/- 0.035 in women (P = .009). Men were 4 times less likely than women to have continued bone loss after parathyroidectomy. Clinical and laboratory parameters cannot identify men with hyperparathyroidism who have bone loss, illustrating the need for routine DXA screening. Despite this, DXA remains underused. Improved screening practices will favorably effect men's health.

Sporadic Primary Hyperparathyroidism in Young Individuals: Different Disease and Treatment?

Younger individuals with hyperparathyroidism may experience severe disease with a higher incidence of multigland disease (MGD) and operative failure, thereby requiring subtotal parathyroidectomy. This study examines the characteristics and surgical outcome of younger compared with older patients with sporadic primary hyperparathyroidism (SPHPT). Prospectively collected data of 1101 patients with SPHPT who underwent parathyroidectomy at a single institution were retrospectively reviewed. Patients with multiple endocrine neoplasia (MEN), familial, secondary, or tertiary hyperparathyroidism, parathyroid carcinoma, rickets, or lithium induced disease were excluded. Patients were subdivided into two groups: (1) younger individuals < or = 40 y of age (n = 110) and (2) older individuals > 40 y of age (n = 991). Both age groups were compared for gender, clinical manifestations, pre- and postoperative laboratory values, MGD, operative success, and recurrent disease. There was greater male predominance in younger compared with older patients treated for SPHPT (41% versus 25%, P = 0.0004). Of the clinical manifestations of SPHPT, kidney stones were more common in younger compared with older individuals (45% versus 29%, P = 0.0006). Conversely, bone pain was more common in older compared with younger patients (32% versus 14%, P = 0.0002). There was no statistical difference in biochemical values, MGD, and outcome between both groups. Despite male predominance and few differences in symptoms, SPHPT is a similar disease entity in both younger and older individuals. Patients from both age groups can be similarly treated for SPHPT with a high rate of operative success. Routine BNE and subtotal parathyroidectomy is not necessary in younger individuals.

Effect of Restrictive Fluid Management and Acute Normovolemic Intraoperative Hemodilution on Transfusion Requirements During Living Donor Hepatectomy

The aim of this study was to evaluate the safety and effectiveness of a restrictive fluid management strategy and acute normovolemic intraoperative hemodilution (ANIH) to decrease transfusion requirements among living-donors for liver transplantation (LDLT). We retrospectively reviewed the data of 114 consecutive LDLT donors. The patients were divided into 2 groups based on whether (Group I; n = 73) or not (Group II; n = 41) a restrictive fluid management strategy with ANIH was used during the procedure. For each group we recorded demographic features, intraoperative and postoperative transfusions, amount of administered intraoperative crystalloid and colloids, intraoperative hemodynamics, preoperative and postoperative laboratory values (renal and liver functions), intraoperative and postoperative urine output, and length of hospital stay. Demographic features and preoperative laboratory values were similar for the 2 groups, except for age (Group I, 36 ± 9 vs Group II, 33 ± 8; P = .04). Intraoperatively, 7 patients (10%) in Group 1 and 9 (22%) in Group II required blood transfusions ( P = .06). The respective amount of heterologous blood transfusion for Groups I and II was 96 ± 321 mL vs 295 ± 678 mL ( P = .06). Postoperative renal and liver functions were not different between the 2 groups ( P > .05). Patients in Group I had a shorter hospital stay than those in Group II (8.2 ± 4.6 days vs 10.1 ± 4.9 days; P = .03). In conclusion, a restrictive fluid management strategy with ANIH was a safe blood-salvage technique for LDLT. This approach was also associated with decreased length of hospital stay and a trend toward decreased transfusion requirements.

Genetic-based dosing in orthopedic patients beginning warfarin therapy

AbstractHigh variability in drug response and a narrow therapeutic index complicate warfarin therapy initiation. No existing algorithm provides recommendations on refining the initial warfarin dose based on genetic variables, clinical data, and international normalized ratio (INR) values. Our goal was to develop such an algorithm. We studied 92 patients undergoing primary or revision total hip or knee replacement. From each patient we collected a blood sample, clinical variables, current medications, and preoperative and postoperative laboratory values. We genotyped for polymorphisms in the cytochrome P450 (CYP) 2C9 and vitamin K epoxide reductase (VKORC1) genes. Using stepwise regression, we developed a model for refining the warfarin dose after the third warfarin dose. The algorithm explained four fifths of the variability in therapeutic dose (R2adj of 79%). Significant (P > .05) predictors were INR value after 3 doses (47% reduction per 0.25-unit rise), first warfarin dose (+7% per 1 mg), CYP2C9*3 and CYP2C9*2 genotype (−38% and −17% per allele), estimated blood loss (interacting with INR3), smoking status (+20% in current smokers), and VKORC1 (−11% per copy of haplotype A). If validated, this model should provide a safer, more effective process for initiating warfarin therapy.

Die Verklebung des perkutanen Arbeitskanales nach kompletter Steinsanierung mit einem Gelatine-Matrix-Hämostypticum (Spongostan)

Parallel to the pilot project of Lee et al. which was published in February 2004, we also considered the possibility to seal the percutaneous nephrolithotomy (PCNL) access after complete stone removal via the local amplatz sheath. We started our project with the aims of increasing postoperative patient comfort, minimizing the risk of bleeding, and reducing postoperative cost and length of the hospital stay by performing this minimally invasive technique in 7 patients with medium stone burden. All patients were treated by removing stones via a working channel passing through the lower pole calix. After complete stone removal a hemostyptic gelatin powder (Spongostan, Johnson & Johnson) was prepared to a doughy paste, some drops of contrast medium were added and the whole material was introduced through the amplatz sheath into the working channel under imaging control. Imaging-controlled insertion of the doughy gelatin clot through the amplatz sheath into the parenchymal part of the channel alone resulted in immediate hemostasis in all patients. The amplatz sheath was retracted over a 28 Fr. rectal tube which was used to push the gelatin forward. There was no need for an additional tamponade of the renal fat capsule or the abdominal wall. After 2 minutes when no channel bleeding was apparent, the skin sutures were placed. Bleeding of the nephrostomy tract did not occur in any of the 7 patients. Average operating time was 50 minutes which was not significantly reduced by performing the new procedure. However, the hospital stay was reduced by 2 days. Two of the patients showed a single fever episode during the second postoperative evening. All patients presented with steady postoperative laboratory values without evidence of bleeding. Free urinary flow from the collecting system was controlled by means of ultrasound and urography. Similar to the recent usage of FloSeal/Baxter reported by Lee et al. we can confirm very reliable and immediate hemostasis using a pasty preparation of Spongostan (Johnson and Johnson) gelatin powder which was classified as being less toxic by the FDA in 2003 due to the lack of glutaraldehyde and bovine thrombin. Therefore, tubeless PCNL can be used for complete percutaneous clearance of stones without bleeding.

Serum Laboratory Values Following Uncomplicated Laparoscopic Urological Surgery

Presentation of complications following laparoscopic surgery can be different from corresponding open surgical complications. While leukopenia has been identified as a common finding in patients with unrecognized bowel injury following laparoscopy, to our knowledge no study has determined if leukopenia or other serum abnormalities are unique to patients with laparoscopic complications. We present an analysis of postoperative laboratory values from patients after uncomplicated urological laparoscopic surgery. A retrospective review of 50 adult patients who had previously undergone uncomplicated laparoscopic urological procedures was performed. Exclusion criteria were preexisting hematological, immune, liver or pancreatic disorders. Common serum laboratory values were measured on postoperative day 1. All values for bilirubin were within normal limits. Of patients undergoing a right side renal procedure, 10 of 16 (63%) had a postoperative increase in liver function tests. Amylase or lipase was increased in a total of 12 (24%) patients. Patients undergoing laparoscopic prostatectomy accounted for the majority of this group with 9 of 21 (43%) patients having increased amylase or lipase. Finally, there were no patients with immediate postoperative leukopenia. Following uncomplicated laparoscopic procedures, bilirubin levels are rarely affected, amylase and lipase may be acutely increased following laparoscopic prostatectomy, and white blood count is commonly increased. While 16 (36%) patients had postoperative leukocytosis, leukopenia was not detected after uncomplicated laparoscopic urological surgery and should alert the surgeon to the possibility of an undiagnosed complication.

Risk factors for postoperative respiratory complications in adult liver transplant recipients

To determine the types and the incidence of as well as risk factors for early postoperative (<30 days) respiratory complications in adult liver transplant (LT) recipients, we reviewed The data of 44 consecutive adult LT recipients who received their grafts from January 1995 through December 2002. The data included demographic features; primary diagnosis; number of intraoperative transfusions; preoperative and postoperative laboratory values; intraoperative and postoperative characteristics; and early postoperative (<30 days) mortality. Pulmonary atelectasis, pleural effusion, pneumonia, respiratory failure, and pulmonary edema were the respiratory complications investigated. Twenty-six patients (59.1%) developed at least one respiratory complication during the early postoperative period. The most frequent complication was pleural effusion (n = 18, 40.9%), followed by atelectasis (n = 13, 29.5%), pneumonia (n = 10, 22.7%), acute respiratory failure (n = 5, 11.4%), pulmonary edema (n = 3, 6.8%), and pneumothorax (n = 2, 4.5%). Compared to the patients who did not develop these problems, the affected cohort was significantly older (27 ± 12 years vs 36 ± 14 years, respectively; P = .039) and required more intraoperative transfusions (P = .005). Among the overall mortality rate of 15.9%, patients who developed pneumonia showed a significantly higher mortality (40.0% vs 8.8%, respectively; P = .037). Pleural effusion, atelectasis, and pneumonia are the main respriatory complications that occur in adult LT recipients. Patient age and intraoperative transfusion requirements are important predictors of early postoperative complications. Pneumonia is associated with a poor prognosis in this patient group.

Use of Erythropoietin Following Emergent Surgery in a Jehovah'S Witness

We report a case of a 25-year-old, female Jehovah'S Witness (JW) with severe anemia secondary to emergent salpingectomy who was treated with high dose human recombinant erythropoietin (rHu-EPO). Post-operative laboratory values were significant for a Hgb of 3.4 g/dl and a Hct 9.6%. The patient received rHu-EPO 150 u/kg IV q 12 hrs x 10 days, iron dextran, folic acid, cyanocobalamin, and fluid replacement. The patients Hgb and Hct were 6.0 g/dl and 18.9% upon discharge, increased from a nadir of 2.4 g/dl and 6.7%, respectively. The immediate administration of high dose rHu-EPO to severely anemic JW patients may decrease the period of severe anemia by accelerating erythropoiesis.

Roux-en-Y gastric bypass: an effective antireflux procedure in the less than morbidly obese.

Since Roux-en-Y gastric bypass (RYGBP) is an excellent antireflux procedure, why is it necessary to do it only for those who are morbidly obese: why not anyone who has had a longstanding severe weight problem with chronic disabling reflux esophagitis? RYGBP was done primarily as an antireflux procedure in 332 patients late from 1987 through October 1996. Eighty-nine were less than 100 lb (45 kg) overweight. Forty-five were lost to follow-up. All but one had Visick ratings from 2 to 4 preoperatively. Thirty-one were primary RYGBP and 13 were conversions from previous gastroplasties. The diagnosis in each case was made by esophagogastroscopy with esophageal biopsy with or without the Bernstein test when indicated. Postoperatively, only one patient was symptomatic. The remaining had Visick ratings of 1. The average preoperative weight of 192 lb (87 kg) dropped to 145 lb (66 kg) postoperatively, or 67% of excess weight loss at a mean of 56 months. Compared to the morbidly obese group, there was no significant difference in 1-year postoperative laboratory values. This study supports the efficacy and safety of RYGBP for reflux esophagitis in the less than morbidly obese patient. Esophagitis is truly a comorbid condition of severe obesity, and it should be accepted as such. The arbitrary elimination from the consideration of candidacy for this procedure by those with a body mass index of less than 35 kg/m2 and unproven comorbidity appears unjustified.

Effect of Heparin Loading During Congenital Heart Operation on Thrombin Generation and Blood Loss

Background. The heparin protocols used during cardiopulmonary bypass (CPB) in children undergoing surgical repair for congenital heart disease are extrapolated from adult data. Studies are needed that assess the optimal heparin dosing in these children, whose heparin clearance is increased compared with that in adults.Methods. We assessed the effects of two commonly used doses of heparin in the prime solution at the start of CPB operation on plasma heparin levels, on thrombin production (thrombin–antithrombin III complexes, prothrombin fragment 1 + 2, D-dimer, and antithrombin III), and on the risk of hemorrhage. Before CPB, 48 children with congenital heart disease received heparin intravenously in a loading dose of 300 U/kg, followed by either 1 U/mL of heparin in the prime (low-dose group: 22 patients—acyanotic, 9; cyanotic, 13) or 3 U/mL of heparin in the prime (group: high-dose, 26 patients—acyanotic, 15; cyanotic, 11).Results. In all patients, CPB resulted in the generation of thrombin. The duration of CPB was a significant covariate factor for heparin levels (p = 0.002), thrombin production (p < 0.001), and postoperative blood loss (p < 0.001). In the patients in the high-dose group, the total heparin dose and the plasma heparin levels were higher (p = 0.0005 and 0.005, respectively) and the D-dimer levels tended to be lower (p = 0.06). The postoperative blood loss was higher in the cyanotic patients (p = 0.02; both high-dose and low-dose groups), with 2 cyanotic patients (1 in low-dose group, 1 in high-dose group) requiring reoperation, one of whom subsequently died. The increased heparin dose had no significant effect on the rate or volume of postoperative blood loss.Conclusions. Increasing the heparin dose in the prime solution from 1 to 3 U/mL increased the plasma heparin levels and showed a trend toward reducing the postoperative laboratory values indicative of fibrinolysis. Thrombin generation during CPB and the incidence of postoperative hemorrhage were not significantly altered. Larger randomized trials are needed to determine the optimal heparin-dosing regimen in patients with congenital heart disease.(Ann Thorac Surg 1997;63:482–8)

Perioperative blood loss: the effect of valproate

The purpose of this investigation was to determine the effect of the use of valproate (VPA) on bleeding and requirement for replacement blood products in patients undergoing major surgical procedures. One hundred thirty-nine patients had posterior spinal fusion performed by 1 of 3 surgeons at our institution from 1987 to 1993. The clinical status of the patient, pre- and postoperative laboratory values, type and extent of instrumentation, surgeon performing the procedure, and medications (including VPA) were variables considered. The outcome measures were intra- and postoperative blood loss and number of blood products used. Intraoperative blood loss was correlated with the method of instrumentation, platelet count, and the surgeon performing the procedure. Postoperative blood loss was correlated with the diagnosis of cerebral palsy. By hierarchical stepwise regression analysis, the only outcome measure correlated with VPA was the number of blood products used.

Postoperative delirium following radical gynecologic oncology surgery

The purpose of this study was to determine the incidence and possible predisposing factors for the development of postoperative delirum following radical gynecologic oncology surgery. A retrospective chart review was performed on 153 consecutive patients undergoing radical gynecologic oncology surgery. Preoperative variables assessed included: age, sepsis, decreased vision, decreased hearing, psychiatric history and abnormal mental status. Operative variables assess included: anesthesia time, estimated blood loss, hypotension, arrhythmia and transfusions. Preoperative medications, postoperative pain medication and abnormal perioperative laboratory values were also assessed. Sixteen of 150 patients (11%) developed postoperative delirium. Age was a significant predictor of postoperative delirium (median age 69 years vs 53 years, P = 0.006). Preoperative abnormal mental status examination was a significant predictor (P = 0.27). Use of chronic narcotic pain medication was significant (P = 0.008). All three patients who were septic at the time of emergency surgery developed postoperative delirum (P = 0.001). No other variables could be identified. When reviewing the date using any high risk factor as a positive test (advanced age, sepsis, abnormal mental status exam or chronic narcotic pain medication), sensitivity was 88%, specificity 76%, positive predictive value 35% and negative predictive value 77%. Delirium occurred most frequently on the second post-operative day (range 1–4 days) and lasted for a median of 2 days (range 1–5 days). Delirium resolved completely in all 16 patients. In conclusion, 11% of women undergoing radical gynecologic oncology surgery developed postoperative delirium. Advanced age, preoperative abnormal mental status, chronic narcotic pain medication and preoperative sepsis were all predisposing risk factors.

Supraventricular tachycardia after coronary artery bypass grafting surgery and fluid and electrolyte variables

Objective To explore the relationship between fluid and electrolyte variables and the development of supraventricular tachycardia (SVT) after coronary artery bypass grafting (CABG) surgery. Design Retrospective chart review. Random selection from a list obtained from the medical records department and with use of the International Classification of Diseases code to identify patients under-going their initial CABG. Setting Medical records department of a southeastern 600-bed urban referral hospital with a large cardiovascular surgical program. Patients Forty patients experiencing SVT and 40 patients not experiencing SVT during their stay in an intensive care unit after CABG. Outcome Measure Fluid and electrolyte variables and the development of SVT in the intensive care unit after CABG. Variables Data collected included preoperative demographic variables such as age and gender; previous history of SVT, congestive heart failure, cardiac arrest, previous surgery, diabetes, hypertension, valve disease, tobacco use, obesity; preoperative and postoperative medications; postoperative laboratory values of potassium, calcium, and magnesium; intravenous intake; hourly urine output; and chest tube drainage. Results Demographic variables revealed that patients with SVT were older ( p=0.001) and had a higher incidence of preoperative SVT ( p=0.04). Although groups did not differ by numbers of patients with high or low potassium, calcium, or magnesium, patients receiving additional intravenous potassium by bolus after surgery had a higher incidence of SVT ( p=0.02). Patients who lost blood via the chest tube at a rate greater than 100 ml per hour for at least 1 hour after surgery had a higher incidence of SVT ( p=0.02). Patients with a urine output greater than 300 ml per hour for longer than 9 hours had an increased incidence of SVT ( p=0.02). In the patients experiencing SVT, 62% had it occur 24 to 48 hours after surgery. Conclusions These data suggest that shifts in fluid and electrolytes may be important characteristics of patients in whom SVT will develop, which could lead to better identification and nursing management of SVT and improve hemodynamic status, patient recovery, and cost after CABG.

Prospective study of the need for long-term antisecretory therapy in patients with Zollinger-Ellison syndrome following successful curative gastrinoma resection.

A long-term cure is now possible in more than 30% of selected patients with Zollinger-Ellison syndrome who undergo gastrinoma resection. The need, however, for continued gastric acid antisecretory therapy in these patients remains controversial. The current study was designed to determine whether post-operative antisecretory therapy is needed in patients who have undergone successful gastrinoma resection and, if so, to attempt to define criteria with which to identify patients who require therapy. Twenty-eight consecutive patients who had previously undergone curative gastrinoma resection were prospectively studied. When antisecretory therapy was discontinued, 43% (12/28) of these patients developed gastro-oesophageal reflux, diarrhoea, acid-peptic symptoms or endoscopic evidence of acid-peptic disease within 2 weeks and were deemed to have failed a trial of antisecretory drug withdrawal. The remaining 57% (16/28) of patients who successfully discontinued antisecretory therapy were followed for a mean time of 31 months after withdrawal of therapy. Analysis of acid output studies pre-operatively, as well as at the time of drug withdrawal, demonstrated that patients who were unable to discontinue antisecretory therapy exhibited higher pre-operative maximal acid output values and higher basal acid output values at the time of attempted drug withdrawal than patients who were able to discontinue therapy. Despite these findings, there was significant overlap in acid output values between groups so that it was not possible to define specific acid output criteria for successful drug withdrawal. Pre-operative clinical characteristics, such as the presence or absence of gastro-esophageal reflux or acid-peptic disease, or post-operative laboratory values, such as the fasting serum gastrin level, did not correlate with the ability to discontinue antisecretory therapy. We conclude that following successful curative gastrinoma resection, 40% of patients still require antisecretory therapy and that both symptom evaluation as well as upper endoscopy should be used to guide attempted drug withdrawal. Although patients who are not able to discontinue therapy have significantly higher acid output measurements than those who are able to discontinue therapy, neither acid output criteria nor any other laboratory or clinical characteristics are able to predict the need for continued antisecretory therapy in these patients.

Primary hyperparathyroidism in younger and older patients: symptoms and outcome of surgery.

Two-hundred and fifty patients undergoing initial exploration for primary hyperparathyroidism were analyzed for differences in clinical presentation, biochemical status, pathology, and outcome of surgery. In patients less than 60 years of age (younger patients, n = 119) the most common preoperative symptoms and signs were fatigue (40.3%), bone pain (33.6%), renal stones (31.0%), hypertension (27.7%), and psychiatric illness (27.7%). In patients greater than or equal to 60 years of age (older patients, n = 131) the most frequent symptoms and signs were hypertension (46.6%), fatigue (35.1%), bone pain (30.5%), muscle weakness (28.2%), and joint pain (22.9%). Renal stones were 2.6 times more common (p less than 0.001, chi 2) in younger patients and hypertension 1.7 times more common (p less than 0.05, chi 2) in older patients. There was no significant difference in the preoperative and postoperative laboratory values typically associated with primary hyperparathyroidism. Double adenomas were more common in older (9.2%) than in younger patients (2.5%, p less than 0.05, chi 2). Surgical cure was obtained in 98.8% of patients, and after parathyroidectomy 83% of the younger and 82% of the older patients experienced substantial relief of pre-operative symptoms. Specific questioning revealed most patients to be symptomatic and older patients appear to receive the same clinical and metabolic benefits from parathyroidectomy as younger patients.