Development and Validation of a Risk Quantification Index for 30-Day Postoperative Mortality and Morbidity in Noncardiac Surgical Patients

ABSTRACT Background: Optimal risk adjustment is a requisite precondition for monitoring quality of care and interpreting public reports of hospital outcomes. Current risk-adjustment measures have been criticized for including baseline variables that are difficult to obtain and inadequately adjusting for highrisk patients. The authors sought to develop highly predictive risk-adjustment models for 30-day mortality and morbidity based only on a small number of preoperative baseline characteristics. They included the Current Procedural Terminology code corresponding to the patient'

Operation Timing Does Not Affect Outcome after Coronary Artery Bypass Graft Surgery

Background: Human factors such as fatigue, circadian rhythms, scheduling, and staffing may have an impact on patient care over the course of a day across all medical specialties. Research by the transportation industry concludes that human performance is degraded by shift work, circadian rhythm disturbances, and prolonged duty. This study investigated whether the timing of coronary artery bypass graft surgery affects outcomes. Methods: The outcomes of coronary artery bypass graft surgery patients were analyzed according to the hour of the day, day of the workweek, month, and moon phase in which the surgery started. All patients who underwent isolated coronary artery bypass graft surgery between January 1, 1993 and July 1, 2006 were considered for the study. The primary outcome measurement was a compound morbidity outcome of six variables defined by the Society of Thoracic Surgeons. These outcomes included (1) in-hospital death, (2) acute postoperative myocardial infarction, (3) neurologic morbidity, including focal or global neurologic deficits or death without awakening, (4) serious infection morbidity consisting of sepsis syndrome or septic shock, (5) new-onset renal failure requiring dialysis, and (6) postoperative ventilatory support exceeding 72 h. Results: The composite morbidity and in-hospital mortality rates were 4.8% and 1.4%, respectively. The number of cases each weekday, each month of the year, and during each phase of the moon were consistent. None of the time factors significantly affected the composite morbidity outcome. Conclusions: Elective coronary artery bypass graft surgery can be scheduled throughout the workday, any day of the work week and in any month of the year without compromising outcome

Acute opioid tolerance: Intraoperative remifentanil increases postoperative pain and morphine requirement. ANESTHESIOLOGY

Background: Rapid development of acute opioid tolerance is well established in animals and is more likely to occur with large doses of short-acting drugs. The authors therefore tested the hypothesis that intraoperative remifentanil administration results in acute opioid tolerance that is manifested by increased postoperative pain and opioid requirement. Methods: Fifty adult patients undergoing major abdominal surgery were randomly assigned to two anesthetic regimens: (1) desflurane was kept constant at 0.5 minimum alveolar concentrations and a remifentanil infusion was titrated to auto

Heme as a Playmaker in the Regulation of the Nitric Oxide System

founding due to this factor. Our results are thus interpreted as the hazard ratio of recurrence for paravertebral versus general anesthesia for patients at the same histologic grade, and similarly for other factors in the model. This sort of multivariable analysis compensates for small, or even moderate, imbalances at baseline. We adjusted for this factor because of the retrospective nature of the study, even though we did not have evidence of it being a true confounder because it was not associated with the treatment groups (P ϭ 0.16) or the outcome (P ϭ 0.25), both of which are required by the classic definition of confounding. As specified in the article, a single surgeon performed all cases in both groups. And again as specified, all paravertebral anesthesia was performed by a single anesthesiologist (D.J.B.), who also performed some of general anesthesia alone cases. The remainder were performed by three other attending anesthesiologists. The cases were similar, and the primary determinant of anesthetic type was assignment to D.J.B., who was the only anesthesiologist in the group familiar with the paravertebral technique. The substantial limitations of observational studies are well known and were discussed in our article. For example, we specified: "Patients were not randomized and clinical care was not standardized, so that selection bias and the effects of unmeasured confounding variables cannot be excluded. For example, patients in the general anesthesia group had slightly larger tumors, smaller margins, and higher chemotherapy rates than patients in the paravertebral group, factors that could affect mortality, although these differences did not reach statistical significance. Relevant information such as the amount of morphine given and the type of chemotherapy used in each group was not available in the records." Under no circumstances should a small retrospective study be the basis for practice, and we suggested no such thing in our report. In contrast, the conclusion of our article was that "this study should be viewed as generating a hypothesis and an estimated effect size for future large randomized controlled trials, which are being planned and which will require several years for execution and analysis." A prospective trial is now in progress (ClinicalTrials.gov No. NCT00418457). Heme as a Playmaker in the Regulation of the Nitric Oxide System To the Editor:-We read with great interest the article by Tsai et al. The authors showed that lipopolysaccharide treatment resulted in a significant increase in type 2 cationic amino acid transporter expression and this effect was reversed by concomitant treatment with hemin ( 2,3 These observations may be consistent with previous work performed by the same authors 4 showing that propofol treatment resulted in a concomitant reduction of both the inducible isoform of nitric oxide synthase and type 2 cationic amino acid transporter expression. In this regard, we also showed that propofol may act as an inducer of HO-1 via activation of the nuclear factor-B pathway. 5 Another point that we believe needs to be raised is in regard to the authors' choice of adding hemin immediately after lipopolysaccharide stimulation, thus not permitting a strong preinduction of HO-1 activity, which would have allowed increased carbon monoxide levels and a reduction of the intracellular heme pool. Interestingly, the authors also showed that tin protoporphyrin, a strong inhibitor of HO activity, results in a significant increase of HO-1 protein (even though in the Results section it was indicated that tin protoporphyrin did not increase protein expression) and partial reversion of hemin effects. The molecular mechanism underlying this effect is still unclear, and several hypotheses may be carried out. One is that HO activity inhibition after tin protoporphyrin treatment results in increased intracellular heme level after strong HO activity inhibition, thus leading to increased HO-

Can anesthetic technique for primary breast cancer surgery affect recurrence or metastasis? Anesthesiology. 2006; 105: 660–664

Background: Regional anesthesia is known to prevent or attenuate the surgical stress response; therefore, inhibiting surgical stress by paravertebral anesthesia might attenuate perioperative factors that enhance tumor growth and spread. The authors hypothesized that breast cancer patients undergoing surgery with paravertebral anesthesia and analgesia combined with general anesthesia have a lower incidence of cancer recurrence or metastases than patients undergoing surgery with general anesthesia and patient-controlled morphine analgesia. Methods: In this retrospective study, the authors examined the medical records of 129 consecutive patients undergoing mastectomy and axillary clearance for breast cancer between September 2001 and December 2002. Results: Fifty patients had surgery with paravertebral anesthesia and analgesia combined with general anesthesia, and 79 patients had general anesthesia combined with postoperative morphine analgesia. The follow-up time was 32 ؎ 5 months (mean ؎ SD). There were no significant differences in patients or surgical details, tumor presentation, or prognostic factors. Recurrence-and metastasis-free survival was 94% (95% confidence interval, 87-100%) and 82% (74 -91%) at 24 months and 94% (87-100%) and 77% (68 -87%) at 36 months in the paravertebral and general anesthesia patients, respectively (P ‫؍‬ 0.012). Conclusions: This retrospective analysis suggests that paravertebral anesthesia and analgesia for breast cancer surgery reduces the risk of recurrence or metastasis during the initial years of follow-up. Prospective trials evaluating the effects of regional analgesia and morphine sparing on cancer recurrence seem warranted