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Articles by P. S Chan
Total Records ( 4 ) for P. S Chan
  P. S Chan , G Nichol , H. M Krumholz , J. A Spertus , B. K Nallamothu and for the American Heart Association National Registry of Cardiopulmonary Resuscitation (NRCPR) Invest

Background  Delays to defibrillation are associated with worse survival after in-hospital cardiac arrest, but the degree to which hospitals vary in defibrillation response times and hospital predictors of delays remain unknown.

Methods  Using hierarchical models, we evaluated hospital variation in rates of delayed defibrillation (>2 minutes) and its impact on survival among 7479 adult inpatients with cardiac arrests at 200 hospitals within the National Registry of Cardiopulmonary Resuscitation.

Results  Adjusted rates of delayed defibrillation varied substantially among hospitals (range, 2.4%-50.9%), with hospital-level effects accounting for a significant amount of the total variation in defibrillation delays after adjusting for patient factors. We found a 46% greater odds of patients with identical covariates getting delayed defibrillation at one randomly selected hospital compared with another. Among traditional hospital factors evaluated, however, only bed volume (reference category: <200 beds; 200-499 beds: odds ratio [OR], 0.62 [95% confidence interval {CI}, 0.48-0.80]; ≥500 beds: OR, 0.74 [95% CI, 0.53-1.04]) and arrest location (reference category: intensive care unit; telemetry unit: OR, 1.92 [95% CI, 1.65-2.22]; nonmonitored unit: OR, 1.90 [95% CI, 1.61-2.24]) were associated with differences in rates of delayed defibrillation. Wide variation also existed in adjusted hospital rates of survival to discharge (range, 5.3%-49.6%), with higher survival among hospitals in the top-performing quartile for defibrillation time (compared with the bottom quartile: OR for top quartile, 1.41 [95% CI, 1.11-1.77]).

Conclusions  Rates of delayed defibrillation vary widely among hospitals but are largely unexplained by traditional hospital factors. Given its association with improved survival, future research is needed to better understand best practices in the delivery of defibrillation at top-performing hospitals.

  P. S Chan , R Jain , B. K Nallmothu , R. A Berg and C. Sasson

Background  Although rapid response teams (RRTs) increasingly have been adopted by hospitals, their effectiveness in reducing hospital mortality remains uncertain. We conducted a meta-analysis to assess the effect of RRTs on reducing cardiopulmonary arrest and hospital mortality rates.

Methods  We conducted a systematic review of studies published from January 1, 1950, through November 31, 2008, using PubMed, EMBASE, Web of Knowledge, CINAHL, and all Evidence-Based Medicine Reviews. Randomized clinical trials and prospective studies of RRTs that reported data on changes in the primary outcome of hospital mortality or the secondary outcome of cardiopulmonary arrest cases were included.

Results  Eighteen studies from 17 publications (with 1 treated as 2 separate studies) were identified, involving nearly 1.3 million hospital admissions. Implementation of an RRT in adults was associated with a 33.8% reduction in rates of cardiopulmonary arrest outside the intensive care unit (ICU) (relative risk [RR], 0.66; 95% confidence interval [CI], 0.54-0.80) but was not associated with lower hospital mortality rates (RR, 0.96; 95% CI, 0.84-1.09). In children, implementation of an RRT was associated with a 37.7% reduction in rates of cardiopulmonary arrest outside the ICU (RR, 0.62; 95% CI, 0.46-0.84) and a 21.4% reduction in hospital mortality rates (RR, 0.79; 95% CI, 0.63-0.98). The pooled mortality estimate in children, however, was not robust to sensitivity analyses. Moreover, studies frequently found evidence that deaths were prevented out of proportion to reductions in cases of cardiopulmonary arrest, raising questions about mechanisms of improvement.

Conclusion  Although RRTs have broad appeal, robust evidence to support their effectiveness in reducing hospital mortality is lacking.

  A. P Amin , S. P Marso , S. V Rao , J Messenger , P. S Chan , J House , K Kennedy , K Robertus , D. J Cohen and E. M. Mahoney

Although bivalirudin compared with unfractionated heparin with glycoprotein IIb/IIIa inhibitors reduces bleeding and hospitalization costs in patients undergoing percutaneous coronary intervention (PCI), little is known about the economic impact of bivalirudin versus heparin alone and at what threshold of procedural bleeding risk bivalirudin would be considered cost-effective.

Methods and Results—

A validated model was used to predict risk of major bleeding for 81 628 National Cardiovascular Data Registry (NCDR) CathPCI Registry patients from 2004 to 2006 who received unfractionated heparin only. Costs were derived from multiple sources including wholesale acquisition costs (for drugs) and single-center data (for PCI-related complications). Based on ISAR-REACT 3, we assumed that bivalirudin would reduce the risk of major bleeding by 33% compared with unfractionated heparin alone. A Markov model was used to estimate lost life expectancy associated with a major bleed. Major bleeding was predicted to occur in 2.2% of patients. Bivalirudin for all patients was estimated to increase costs by $571 per patient, yielding cost-effectiveness ratios of $287 473 per bleeding event averted and $1 173 360 per quality-adjusted life-year gained. Bivalirudin was cost saving for patients with a predicted bleeding risk >20% (0.16% of CathPCI population). At willingness-to-pay thresholds of $50K and $100K per quality-adjusted life-year gained, bivalirudin was cost-effective for patients with a bleeding risk ≥8% (2.5% patients) and ≥5% (7.9% patients), respectively.


This decision-analytic modeling study demonstrates that for patients undergoing PCI, substitution of bivalirudin for unfractionated heparin monotherapy is projected to increase costs for virtually all patients and would be considered cost-effective for only a minority of patients with a high bleeding risk. From a policy standpoint, studies such as this, aimed at identifying the appropriate risk threshold for initiating treatment, may help in the development of informed guidelines for the use of expensive therapies.

  P. D Levy , H Ye , S Compton , P. S Chan , G. L Larkin , R. D Welch and for the American Heart Association National Registry of Cardiopulmonary Resuscitation Investigators

Background— Hospitalized patients with heart failure are at risk for cardiac arrest. The ability to predict who may survive such an event with or without neurological deficit would enhance the information on which patients and providers establish resuscitative preferences.

Methods and Results— We identified 13 063 adult patients with acute heart failure who had cardiac arrest at 457 hospitals participating in the National Registry of Cardiopulmonary Resuscitation between January 1, 2000 and December 31, 2007. Neurological status was determined on admission and discharge by cerebral performance category with neurologically intact survival (NIS)=cerebral performance category 1 (no) or 2 (moderate dysfunction) and non-NIS=cerebral performance category 3 (severe dysfunction), 4 (coma), or 5 (brain death). Factors available prearrest (demographics, preexisting conditions, and interventions in-place) were assessed for association with NIS using multivariable logistic regression, initially without then with adjustment for arrest-related variables and hospital characteristics. NIS occurred in 2307 patients (17.7%) and was associated by adjusted odds ratio with 18 prearrest factors; 4 positively and 14 negatively. The association (odds ratio; 95% CI) was strongest for 4 specific variables: acute stroke (0.38; 0.25 to 0.58), history of malignancy (0.49; 0.39 to 0.63), vasopressor use (0.50; 0.43 to 0.59), and assisted or mechanical ventilation (0.53; 0.45 to 0.61).

Conclusions— A number of prearrest factors seem to be associated with NIS, the majority inversely. Consideration of these before cardiac arrest could enhance the resuscitative decision-making process for patients with acute heart failure.

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