A comparison of four risk models for the prediction of cardiovascular complications in patients with a history of atrial fibrillation undergoing non-cardiac surgery.

It is unclear how best to predict peri-operative cardiovascular risk in patients with atrial fibrillation undergoing non-cardiac surgery. This study examined the accuracy of the revised cardiac risk index and three atrial fibrillation thrombo-embolic risk models for predicting 30-day cardiovascular events after non-cardiac surgery in patients with a pre-operative history of atrial fibrillation. We conducted a prospective cohort study in 28 centres from 2007 to 2013 of 40,004 patients ≥ 45 years of age undergoing inpatient non-cardiac surgery who were followed until 30 days after surgery for cardiovascular events (defined as myocardial injury, heart failure, stroke, resuscitated cardiac arrest or cardiovascular death). The 2088 patients with a pre-operative history of atrial fibrillation were at higher risk of peri-operative cardiovascular events compared with the 34,830 patients without a history of atrial fibrillation (29% vs. 13%, respectively, adjusted odds ratio 1.30 (95%CI 1.17-1.45). Compared with the revised cardiac risk index (c-index 0.60), all atrial fibrillation thrombo-embolic risk scores were significantly better at predicting peri-operative cardiovascular events: CHADS2 (c-index 0.62); CHA2 DS2 -VASc (c-index 0.63); and R2 CHADS2 (c-index 0.65), respectively. Although the three thrombo-embolic risk prediction models were significantly better than the revised cardiac risk index for prediction of peri-operative cardiovascular events, none of the four models exhibited strong discrimination metrics. There remains a need to develop a better peri-operative risk prediction model.

Implication of Major Adverse Postoperative Events and Myocardial Injury on Disability and Survival: A Planned Subanalysis of the ENIGMA-II Trial.

BACKGROUND: Globally, >300 million patients have surgery annually, and ≤20% experience adverse postoperative events. We studied the impact of both cardiac and noncardiac adverse events on 1-year disability-free survival after noncardiac surgery. METHODS: We used the study cohort from the Evaluation of Nitrous oxide in Gas Mixture of Anesthesia (ENIGMA-II) trial, an international randomized trial of 6992 noncardiac surgical patients. All were ≥45 years of age and had moderate to high cardiac risk. The primary outcome was mortality within 1 postoperative year. We defined 4 separate types of postoperative adverse events. Major adverse cardiac events (MACEs) included myocardial infarction (MI), cardiac arrest, and myocardial revascularization with or without troponin elevation. MI was defined using the third Universal Definition and was blindly adjudicated. A second cohort consisted of patients with isolated troponin increases who did not meet the definition for MI. We also considered a cohort of patients who experienced major adverse postoperative events (MAPEs), including unplanned admission to intensive care, prolonged mechanical ventilation, wound infection, pulmonary embolism, and stroke. From this cohort, we identified a group without troponin elevation and another with troponin elevation that was not judged to be an MI. Multivariable Cox proportional hazard models for death at 1 year and assessments of proportionality of hazard functions were performed and expressed as an adjusted hazard ratio (aHR) and 95% confidence intervals (CIs). RESULTS: MACEs were observed in 469 patients, and another 754 patients had isolated troponin increases. MAPEs were observed in 631 patients. Compared with control patients, patients with a MACE were at increased risk of mortality (aHR, 3.36 [95% CI, 2.55-4.46]), similar to patients who suffered a MAPE without troponin elevation (n = 501) (aHR, 2.98 [95% CI, 2.26-3.92]). Patients who suffered a MAPE with troponin elevation but without MI had the highest risk of death (n = 116) (aHR, 4.29 [95% CI, 2.89-6.36]). These 4 types of adverse events similarly affected 1-year disability-free survival. CONCLUSIONS: MACEs and MAPEs occur at similar frequencies and affect survival to a similar degree. All 3 types of postoperative troponin elevation in this analysis were associated, to varying degrees, with increased risk of death and disability.

Covert stroke after non-cardiac surgery: a prospective cohort study.

BACKGROUND: Overt stroke after non-cardiac surgery has a substantial impact on the duration and quality of life. Covert stroke in the non-surgical setting is much more common than overt stroke and is associated with an increased risk of cognitive decline and dementia. Little is known about covert stroke after non-cardiac, non-carotid artery surgery. METHODS: We undertook a prospective, international cohort study to determine the incidence of covert stroke after non-cardiac, non-carotid artery surgery. Eligible patients were ≥65 yr of age and were admitted to hospital for at least three nights after non-cardiac, non-carotid artery surgery. Patients underwent a brain magnetic resonance study between postoperative days 3 and 10. The main outcome was the incidence of perioperative covert stroke. RESULTS: We enrolled a total of 100 patients from six centres in four countries. The incidence of perioperative covert stroke was 10.0% (10/100 patients, 95% confidence interval 5.5-17.4%). Five of the six centres that enrolled patients reported an incident covert stroke, and covert stroke was found in patients undergoing major general (3/27), major orthopaedic (3/41), major urological or gynaecological (3/22), and low-risk surgery (1/12). CONCLUSIONS: This international multicentre study suggests that 1 in 10 patients ≥65 yr of age experiences a perioperative covert stroke. A larger study is required to determine the impact of perioperative covert stroke on patient-important outcomes. CLINICAL TRIAL REGISTRATION: NCT01369537.

The prediction of postoperative stroke or death in patients with preoperative atrial fibrillation undergoing non-cardiac surgery: a VISION sub-study.

BACKGROUND: The optimal means of pre-operative risk stratification in patients with atrial fibrillation (AF) is uncertain. OBJECTIVE: To examine the accuracy of AF thromboembolic risk models (the CHADS2, CHA2DS2-VASc, and R2CHADS2 scores) for predicting 30-day stroke and/or all-cause mortality after non-cardiac surgery in patients with preoperative AF, and to compare these risk scores with the Revised Cardiac Risk Index (RCRI). PATIENTS/METHODS: A multicentre (8 countries, 2007-2011) prospective cohort study of patients ≥ 45 years of age undergoing inpatient non-cardiac surgery, who were followed until 30 days after surgery. We calculated c-statistics for each risk prediction model and net reclassification improvements (NRIs) compared with the RCRI. RESULTS: The 961 patients with preoperative AF were at higher risk of any cardiovascular event in the 30 days postoperatively compared with the 13 001 patients without AF: 26.6% vs. 9.0%; adjusted odds ratio, 1.58; 95% confidence interval [CI], 1.33-1.88. All thromboembolic risk scores predicted postoperative death just as well as the RCRI (with c-indices between 0.67 and 0.72). Compared with the RCRI (which had a c-index of 0.64 for 30-day stroke/death), the CHADS2 (c-index, 0.67; NRI, 0.31; 95% CI, 0.02-0.61) significantly improved postoperative stroke/mortality risk prediction, largely due to improved discrimination of patients who did not subsequently have an event. CONCLUSIONS: In AF patients, the three thromboembolic risk scores performed similarly to the RCRI in predicting death within 30 days and the CHADS2 score was the best predictor of postoperative stroke/death regardless of type of surgery.

New multichannel electron energy analyzer with cylindrically symmetrical electrostatic field.

This article discusses an electron energy analyzer with a cylindrically symmetrical electrostatic field, designed for rapid Auger analysis. The device was designed and built. The best parameters of the analyzer were estimated and then experimentally verified.

Laser cooling transitions in atomic erbium.

We discuss laser cooling opportunities in atomic erbium, identifying five J ? J + 1 transitions from the 4f126s2 3H6 ground state that are accessible to common visible and near-infrared continuous-wave tunable lasers. We present lifetime measurements for the 4f11(4Io 15/2)5d5/26s2 (15/2, 5/2)7o state at 11888 cm-1 and the 4f11(4Io 13/2)5d3/26s2 (13/2, 5/2)7o state at 15847 cm-1, showing values of 20 +/- 4 micros and 5.6 +/- 1.4 micros, respectively. We also present a calculated value of 13 +/- 7 s-1 for the transition rate from the 4f11(4Io 15/2)5d3/26s2 (15/2, 3/2)7 o state at 7697 cm-1 to the ground state, based on scaled Hartree-Fock energy parameters. Laser cooling on these transitions in combination with a strong, fast (5.8 ns) laser cooling transition at 401 nm, suggest new opportunities for narrowband laser cooling of a large-magnetic moment atom, with possible applications in quantum information processing, high-precision atomic clocks, quantum degenerate gases, and deterministic single-atom doping of materials.

A differentially pumped secondary electron detector for low-vacuum scanning electron microscopy.

A new design of secondary electron (SE) detector is described for use in low-vacuum scanning electron microscopes. Its distinguishing feature is a separate detector chamber, which can be maintained at a pressure independent of the pressure in the specimen chamber. The two chambers are separated by a perforated membrane or mesh across which an electric field is applied, making it relatively transparent to low-energy electrons but considerably less so to the gas molecules. The benefits of this arrangement are discussed. The final means of detecting the electrons can be a conventional scintillator and photomultiplier arrangement or any of the methods using the ambient gas as an amplifying medium. Images obtained with the detector show good SE contrast and low backscattered electron contribution.

Ondansetron is more effective than metoclopramide for the treatment of opioid-induced emesis in post-surgical adult patients. Ondansetron OIE Post-Surgical Study Group.

Nausea and vomiting are common side effects of opioids administered for pain control. This double-blind, randomized, parallel-group study evaluated the anti-emetic efficacy and tolerability of single intravenous (i.v.) doses of ondansetron 8 mg, ondansetron 16 mg and metoclopramide 10 mg in the treatment of opioid-induced emesis. Adult patients undergoing low emetogenic surgical procedures, using a standardized anaesthesia regimen were assessed for 24 h following administration of study anti-emetic to treat established post-surgical opioid-induced emesis. A total of 4511 patients were enrolled of whom 1366 experienced opioid-induced emesis and received randomized study medication. Ondansetron 8 mg and 16 mg were significantly better than metoclopramide 10 mg (P < 0.05) for both complete control of emesis, complete control of nausea and other efficacy measures. There were no significant differences between the two ondansetron groups. All three treatments were well tolerated. In conclusion, this large, multicentre study demonstrates that ondansetron is more effective than metoclopramide in the treatment of opioid-induced emesis following administration of post-surgical opioids to control pain.

Delayed presentation of traumatic parasternal lung hernia.

Traumatic lung herniation is an unusual clinical problem. This case report describes a morbidly obese individual who sustained significant chest trauma in a motor vehicle accident. Lung herniation was noted at the time of delayed respiratory failure necessitating ventilation. The significance of the lung hernia in this patient's respiratory failure is uncertain. The lung hernia was repaired surgically to relieve pain, prevent incarceration, and optimize respiratory function. After a brief period of postoperative ventilation, the patient recovered markedly and has been well since.

Diazepam's effect on systemic vascular resistance during cardiopulmonary bypass is not caused by its vehicle (alcohol-propylene glycol).

Control of hemodynamic parameters during cardiopulmonary bypass (CPB) is a desirable goal of the anesthesiologist. Diazepam is known to reduce systemic vascular resistance (SVR) during CPB. This study tested the hypothesis that diazepam reduces SVR during CPB through the action of its vehicle, alcohol-propylene glycol (APG). The study protocol was approved by the Institution's Human Experimentation Review Board and all patients gave informed consent. Premedication, induction, and maintenance of anesthesia were standardized. Thirty consecutive patients undergoing nonemergent cardiac surgical procedures were randomized to receive a standardized amount of diazepam, diazemuls, or alcohol-propylene glycol during stable CPB. SVR in the diazepam group decreased significantly (1,242 to 968 dyne.s.cm-5, P < 0.05) compared to baseline; whereas there was no significant change in SVR in the diazemul group, and a statistically significant increase in SVR (1,217 to 1,537 dyne.s.cm-5, P < 0.05) in the APG group. It is concluded that diazepam reduces SVR during CPB. Diazepam's vehicle does not reduce SVR during CPB, and is in fact associated with an increase in SVR.