Plasma corin decreases after coronary artery bypass graft surgery and is associated with postoperative heart failure: a pilot study.

OBJECTIVE: Corin is a natriuretic peptide-converting enzyme that cleaves precursor pro-B-type natriuretic peptide to active B-type natriuretic peptide (BNP) (diuretic, natriuretic, and vasodilatory properties). Increased plasma BNP is a known diagnostic and prognostic heart failure (HF) biomarker in ambulatory and surgical patients. Recent studies indicate that plasma corin is decreased significantly in chronic HF patients, yet perioperative plasma corin concentrations have not been assessed in cardiac surgical patients. The objectives of this study were to determine the effect of coronary artery bypass graft (CABG) surgery with cardiopulmonary bypass (CPB) on plasma corin concentrations and to assess the association between change in perioperative plasma corin concentration and long-term postoperative HF hospitalization or death. It was hypothesized that plasma corin concentrations decrease significantly from preoperative baseline during postoperative days 1 to 4 and that hospitalization or death from HF during the 5 years after surgery is associated with higher relative difference (preoperative baseline to postoperative nadir) in plasma corin concentrations. DESIGN: Prospective observational pilot study. SETTING: Two institutions: Brigham and Women's Hospital, Boston, Massachusetts and the Texas Heart Institute, St. Luke's Hospital, Houston, Texas. PARTICIPANTS: 99 patients of European ancestry who underwent isolated primary CABG surgery with CPB. INTERVENTIONS: Nonemergency isolated primary CABG surgery with CPB. MEASUREMENTS AND MAIN RESULTS: Plasma corin concentration was assessed preoperatively and at 4 postoperative time points (postoperative days 1-4). HF hospitalization or HF death events during the 5 years after surgery were identified by review of hospital and death records. Postoperative plasma corin concentrations were significantly lower than preoperative baseline concentrations (p<0.0001). Perioperative corin concentrations were significantly higher in males than in females (p<0.0001). Fifteen patients experienced long-term postoperative HF events. Patients who experienced HF hospitalization or HF death during study follow-up had significantly higher relative difference in plasma corin concentration (preoperative baseline to postoperative nadir) than patients who did not experience HF events during study follow-up (p=0.03). CONCLUSIONS: Plasma corin concentrations decrease significantly from preoperative concentrations after CABG surgery. HF hospitalization or HF death during the 5 years after CABG surgery with CPB is associated with larger relative decrease in plasma corin concentration from preoperative baseline. Further investigation is warranted to determine the role of corin in postoperative HF biology.

Surgery at the end of life: a pilot study comparing decedents and survivors at a tertiary care center.

BACKGROUND: More than a quarter of medical costs for Medicare beneficiaries are incurred in the last year of life; surgical intensity during this time is significant. This study was performed to determine types of operations patients undergo in their terminal year, and compare characteristics of decedents with those of survivors. METHODS: Population of 747 consecutive all-payer patients seen at the preoperative assessment center of a tertiary care hospital. Patient characteristics were obtained from the electronic medical record. Surgical indication (palliative, curative, diagnostic, elective) was assessed based on procedure performed and underlying diagnosis. Vital status was determined using the electronic medical record with confirmation via social security national death master file. Descriptive statistics were performed to compare patient characteristics and procedures performed on those who died within 1 yr of procedure with those of survivors. RESULTS: Thirty-seven patients (5%) were confirmed dead at 1 yr. Ten (27%) of these had palliative procedures, 11 (30%) diagnostic, 14 (38%) curative, and 2 (5%) elective. Decedents were more likely to have undergone a palliative (27 vs. 3%) or diagnostic (30 vs. 14%) procedure and less likely to have undergone an elective procedure (5 vs. 42%) than survivors (P < 0.0001). Nearly half of decedents did not have an advanced directive by the date of surgical intervention. CONCLUSIONS: Nearly 1 in 20 patients seen at the preoperative assessment clinic of a tertiary care hospital died within 1 yr of their procedure. Patient characteristics and procedure indication for decedents differed from those of survivors. Similar analyses based on institution and region may provide methodologies to compare variation in surgical intensity and assist preoperative care providers in evaluating appropriateness of resource allocation.

Site 1 sodium channel blockers prolong the duration of sciatic nerve blockade from tricyclic antidepressants.

Many recent reports in the literature address the local anesthetics efficacy of tricyclic antidepressants (TCAs). Here we investigated whether nerve block from TCAs is prolonged by site 1 sodium channel blockers such as tetrodotoxin and saxitoxin, which are known to prolong block from conventional local anesthetics. Tetrodotoxin and saxitoxin greatly prolonged block from TCAs. For example, the median duration of thermal nociceptive blocks for 10 mM amitriptyline, nortriptyline and doxepin were 0, 0, and 124 min; co-injection with 20 microM TTX (median block duration=0), yielded blocks lasting 404, 325, and 697 min, respectively. Co-injection of 12 microM saxitoxin (median block duration=0) with 10 mM amitriptyline resulted in a thermal nociceptive block duration of 373 min. Co-injection of 7.7 mM bupivacaine and 7.7 mM amiptriptyline did not result in block prolongation. Systemic (subcutaneous) delivery of tetrodotoxin or amitriptyline did not result in prolongation of block from the other class of drug injected at the sciatic nerve. In TCA-containing formulations, motor blockade was consistently longer than thermal nociceptive block; motor blockade was also prolonged by tetrodotoxin and saxitoxin. In summary site 1 sodium channel blockers prolong the duration of TCAs via a locally mediated mechanism.

A randomized trial of automated electronic alerts demonstrating improved reimbursable anesthesia time documentation.

STUDY OBJECTIVE: To investigate whether alerting providers to errors results in improved documentation of reimbursable anesthesia care. DESIGN: Prospective randomized controlled trial. SETTING: Operating room (OR) of a university hospital. INTERVENTIONS: Anesthesia cases were evaluated to determine whether they met the definition for appropriate anesthesia start time over 4 separate, 45-day calendar cycles: the pre-study period, study period, immediate post-study period, and 3-year follow-up period. During the study period, providers were randomly assigned to either a control or an alert group. Providers in the alert cohort received an automated alphanumeric page if the anesthesia start time occurred concurrently with the patient entering the OR, or more than 30 minutes before entering the OR. MEASUREMENTS: Three years after the intervention period, overall compliance was analyzed to assess learned behavior. MAIN RESULTS: Baseline compliance was 33% ± 5%. During the intervention period, providers in the alert group showed 87% ± 6% compliance compared with 41% ± 7% compliance in the control group (P < 0.001). Long-term follow-up after cessation of the alerts showed 85% ± 4% compliance. CONCLUSIONS: Automated electronic reminders for time-based billing charges are effective and result in improved ongoing reimbursement.

Tissue injury from tricyclic antidepressants used as local anesthetics.

Neurotoxicity has been reported with tricyclic antidepressants (TCAs) used as local anesthetics. We examined the hypothesis that TCAs cause tissue injury, particularly myotoxicity, as occurs with many local anesthetics. Animals were given sciatic nerve injections with 0-80 mM doxepin, amitriptyline, or bupivacaine (1.5 mL for histological studies, 0.3 mL for neurobehavioral studies). Four days after injection, the TCAs caused ischemic tissue injury. Subcutaneous tissue showed expansion and hardening, with hemorrhage and adhesion to overlying skin. Muscle was diffusely pale. Histopathology showed coagulative necrosis of muscle and surrounding soft tissues, with thrombus formation in vasculature near affected areas. These findings were much reduced with bupivacaine. TCA-injected and bupivacaine-injected animals also developed characteristic local anesthetic myotoxicity. Amitriptyline proved less potent than bupivacaine as a local anesthetic: the concentrations required to provide 100 min of nerve block were 20 mM and 3 mM, respectively. Some animals receiving large concentrations of amitriptyline developed spontaneous recrudescence of nerve blockade or had irreversible nerve blockade, both of which may reflect nerve injury. Neither finding occurred in animals injected with bupivacaine. TCAs do not appear to offer any advantages over conventional local anesthetics and do appear to risk substantially increased toxicity.