Alvin C. Kwok
University of Utah
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Featured researches published by Alvin C. Kwok.
Annals of Surgery | 2013
Alvin C. Kwok; Luke M. Funk; Ruslan Baltaga; Lipsitz; Alan Merry; Gerald Dziekan; G Ciobanu; William R. Berry; Atul A. Gawande
Objective:To introduce the World Health Organization Surgical Safety Checklist into every operating room within a severely resource-limited hospital located in a developing country and to measure its impact on surgical hazards and complications. Background:The checklist has been shown to reduce surgical morbidity and mortality, but the ability to successfully implement the checklist program hospital-wide in lower income settings without basic resources is unknown. Methods:We conducted a pre- versus postintervention study of the implementation of the checklist, including the introduction of universal pulse oximetry at a hospital in Chisinau, Moldova, where only 3 oximeters were available for their 22 operating stations. We supplied data-recording oximeters for all operating stations and trained a local checklist implementation team. The primary outcomes were process adherence, major complications, and rates of hypoxemia (SpO2 <90%). Propensity score weighing was conducted to adjust process and outcome measures. Regression models were used to evaluate adherence to process measures and hypoxemia trends over time. Results:Data from 2145 pre- and 2212 postintervention cases were collected. Adherence to all safety processes increased significantly from 0.0% to 66.9% (P < 0.001). After checklist implementation, the overall complication rate decreased from 21.5% to 8.8% (P < 0.001). Infectious and noninfectious complications decreased significantly after checklist implementation from 17.7% to 6.7% (P < 0.001) and from 2.6% to 1.5% (P = 0.018), respectively. The number of hypoxemic episodes lasting 2 minutes or longer per 100 hours of oximetry decreased from 11.5 to 6.4 (P < 0.002). Conclusions:Successful hospital-wide Surgery Safety Checklist implementation can be achieved in a resource-limited setting and can significantly reduce surgical hazards and complications.
Journal of The American College of Surgeons | 2011
Alvin C. Kwok; Stuart R. Lipsitz; Angela M. Bader; Atul A. Gawande
BACKGROUND Whether preoperative risk prediction improves with the use of more patient- and procedure-targeted models is unclear. We created a customized preoperative mortality risk prediction score for patients 80 years or older needing an emergency colectomy and compare it with existing, more generic risk assessment methods. STUDY DESIGN A targeted mortality prediction model was created using 2007 to 2008 American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) data and was validated using 2005 to 2006 data. We constructed a scoring system from the significant predictors identified. The model fit of our targeted score was compared with the American Society of Anesthesiologists (ASA) score, the Surgical Risk Scale, and the ACS Colorectal Surgery Risk Calculator. RESULTS Analyses identified 1,358 and 372 emergency colectomies in the training and validation samples, respectively. Our targeted risk prediction score had a goodness-of-fit p value greater than 0.05 (indicating a good fit) and a c-statistic of 0.77, which represents a significantly better fit compared with the ASA score, the Surgical Risk Scale, and the ACS Colorectal Surgery Risk Calculator c-statistics (0.66, 0.66, and 0.71, respectively). When using the scores to predict mortality with 80% specificity, our targeted risk prediction score was 25% more likely to predict correctly than the ACS Colorectal Surgery Risk Calculator and 33% more likely to predict correctly compared with the ASA score and Surgical Risk Scale. CONCLUSIONS Our study presents a validated preoperative mortality score for very elderly patients needing an emergency colectomy. The greater discriminating power of this targeted score indicates that preoperative risk assessment may need to be customized to specific procedures and patient circumstances.
Journal of the National Cancer Institute | 2012
Yue Yung Hu; Alvin C. Kwok; Wei Jiang; Nathan Taback; Elizabeth T. Loggers; Gladys Ting; Stuart R. Lipsitz; Jane C. Weeks; Caprice C. Greenberg
BACKGROUND Medicare expenditures for high-cost diagnostic imaging have risen faster than those for total cancer care and have been targeted for potential cost reduction. We sought to determine recent and long-term patterns in high-cost diagnostic imaging use among elderly (aged ≥65 years) patients with stage IV cancer. METHODS We identified claims within the Surveillance, Epidemiology, and End Results (SEER)-Medicare database with computed tomography, magnetic resonance imaging, positron emission tomography, and nuclear medicine scans between January 1994 and December 2009 for patients diagnosed with stage IV breast, colorectal, lung, or prostate cancer between January 1995 and December 2006 (N = 100,594 patients). The proportion of these patients imaged and rate of imaging per-patient per-month of survival were calculated for each phase of care in patients diagnosed between January 2002 and December 2006 (N = 55,253 patients). Logistic regression was used to estimate trends in imaging use in stage IV patients diagnosed between January 1995 and December 2006, which were compared with trends in imaging use in early-stage (stages I and II) patients with the same tumor types during the same period (N = 192,429 patients). RESULTS Among the stage IV patients diagnosed between January 2002 and December 2006, 95.9% underwent a high-cost diagnostic imaging procedure, with a mean number of 9.79 (SD = 9.77) scans per patient and 1.38 (SD = 1.24) scans per-patient per-month of survival. After the diagnostic phase, 75.3% were scanned again; 34.3% of patients were scanned in the last month of life. Between January 1995 and December 2006, the proportion of stage IV cancer patients imaged increased (relative increase = 4.6%, 95% confidence interval [CI] = 3.7% to 5.6%), and the proportion of early-stage cancer patients imaged decreased (relative decrease = -2.5%, 95% CI = -3.2% to -1.9%). CONCLUSIONS Diagnostic imaging is used frequently in patients with stage IV disease, and its use increased more rapidly over the decade of study than that in patients with early-stage disease.
JAMA Surgery | 2015
Rebecca Y. Kim; Gifty Kwakye; Alvin C. Kwok; Ruslan Baltaga; Gheorghe Ciobanu; Alan Merry; Luke M. Funk; Stuart R. Lipsitz; Atul A. Gawande; William R. Berry; Alex B. Haynes
IMPORTANCE Little is known about the sustainability and long-term effect of surgical safety checklists when implemented in resource-limited settings. A previous study demonstrated the marked, short-term effect of a structured hospital-wide implementation of a surgical safety checklist in Moldova, a lower-middle-income country, as have studies in other low-resource settings. OBJECTIVES To assess the long-term reduction in perioperative harm following the introduction of a checklist-based surgical quality improvement program in a resource-limited setting and to understand the long-term effects of such programs. DESIGN, SETTING, AND PARTICIPANTS Twenty months after the initial implementation of a surgical safety checklist and the provision of pulse oximetry at a referral hospital in Moldova, a lower-middle-income, resource-limited country in Eastern Europe, we conducted a prospective study of perioperative care and outcomes of 637 consecutive patients undergoing noncardiac surgery (the long-term follow-up group), and we compared the findings with those from 2106 patients who underwent surgery shortly after implementation (the short-term follow-up group). Preintervention data were collected from March to July 2010. Data collection during the short-term follow-up period was performed from October 2010 to January 2011, beginning 1 month after the implementation of the launch period. Data collection during the long-term follow-up period took place from May 25 to July 6, 2012, beginning 20 months after the initial intervention. MAIN OUTCOMES AND MEASURES The primary end points of interest were surgical morbidity (ie, the complication rate), adherence to safety process measures, and frequency of hypoxemia. RESULTS Between the short- and long-term follow-up groups, the complication rate decreased 30.7% (P = .03). Surgical site infections decreased 40.4% (P = .05). The mean (SD) rate of completion of the checklist items increased from 88% (14%) in the short-term follow-up group to 92% (11%) in the long-term follow-up group (P < .001). The rate of hypoxemic events continued to decrease (from 8.1 events per 100 hours of oximetry for the short-term follow-up group to 6.8 events per 100 hours of oximetry for the long-term follow-up group; P = .10). CONCLUSIONS AND RELEVANCE Sustained use of the checklist was observed with continued improvements in process measures and reductions in 30-day surgical complications almost 2 years after a structured implementation effort that demonstrated marked, short-term reductions in harm. The sustained effect occurred despite the absence of continued oversight by the research team, indicating the important role that local leadership and local champions play in the success of quality improvement initiatives, especially in resource-limited settings.
American Journal of Surgery | 2015
Alvin C. Kwok; Isak A. Goodwin; Jian Ying; Jayant P. Agarwal
BACKGROUND This studys purpose was to examine the national rate of breast cancer patients undergoing bilateral mastectomy (BM) and immediate breast reconstruction (IBR) and their associated complication rates. METHODS Using the National Surgical Quality Improvement Program database, breast cancer patients undergoing mastectomy between 2005 and 2012 were identified. Rates in BM and IBR as well as associated complication rates were evaluated. Logistic regression was used to identify predictors of BM, IBR, and complications. RESULTS A total of 56,905 breast cancer patients underwent mastectomy. The rate of BM tripled (9.14% vs 25.44%, P < .0001) and the rate of IBR increased by 50% (29.73% vs 44.68%, P < .0001). Complication rates were higher in patients undergoing BM compared with unilateral mastectomy (11.49% vs 9.52%, P < .0001) and in patients undergoing IBR compared with mastectomy alone (11.62% vs 8.91%, P < .0001). White race and age less than 40 years were predictors of patients undergoing BM and IBR. CONCLUSIONS The rates of BM and associated IBR have increased significantly since 2005 despite higher complication rates. Further research is needed to understand the reasons for these trends.
Journal of Neuro-oncology | 2006
Virany Huynh Hillard; James K. Liu; Alvin C. Kwok; Meic H. Schmidt
Spinal cord involvement by perineural spread of malignant mesothelioma is rare. We report a case of malignant mesothelioma that spread locally to invade the bony spine with both extradural and intradural perineural spread into the spinal canal that resulted in spinal cord compression. A 61-year-old man with a history of malignant mesothelioma presented with progressive leg weakness and right-sided arm weakness. Magnetic resonance imaging showed an enhancing lesion in the apex of the right lung with extension through the C7–T1 foramina with right hemicord enhancement. The patient underwent a C7–T1 laminectomy and right-sided C7–T1 and T1–T2 foraminotomies for neural decompression and biopsy of the lesion. Intraoperatively, tumor extended epidurally, and intradural perineural tumor spread along the C8 and T1 nerve roots into the spinal cord. Because it adhered to the spinal cord, no dissectible plane could be identified that would allow for safe total removal of the tumor. The epidural portion of the tumor, the adjacent involved bone, and the T1 nerve root were resected. Pathologic examination revealed malignant mesothelioma with bony invasion and perineural spread along the T1 nerve root. After decompression of the spinal cord, the patient had moderate improvement of his hand and leg function. Perineural spread of malignant mesothelioma resulting in spinal cord compression is an unusual clinical presentation. Intimate involvement of the spinal cord may prohibit aggressive tumor resection.
JAMA Surgery | 2015
Margaret L Schwarze; Amber E. Barnato; Paul J. Rathouz; Qianqian Zhao; Heather B. Neuman; Emily R. Winslow; Gregory D. Kennedy; Yue Yung Hu; Christopher M. Dodgion; Alvin C. Kwok; Caprice C. Greenberg
IMPORTANCE No consensus exists regarding the definition of high-risk surgery in older adults. An inclusive and precise definition of high-risk surgery may be useful for surgeons, patients, researchers, and hospitals. OBJECTIVE To develop a list of high-risk operations. DESIGN, SETTING, AND PARTICIPANTS Retrospective cohort study and modified Delphi procedure. The setting included all Pennsylvania acute care hospitals (Pennsylvania Health Care Cost Containment Council [PHC4] April 1, 2001, to December 31, 2007) and a nationally representative sample of US acute care hospitals (Nationwide Inpatient Sample [NIS], Healthcare Cost and Utilization Project, Agency for Healthcare Research and Quality January 1, 2001, to December 31, 2006). Patients included were those 65 years and older admitted to PHC4 hospitals and those 18 years and older admitted to NIS hospitals. We identified International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) procedure codes associated with at least 1% inpatient mortality in the PHC4. We used a modified Delphi procedure with 5 board-certified surgeons to further refine this list by excluding nonoperative procedures and operations that were unlikely to be the proximate cause of mortality and were instead a marker of critical illness (eg, tracheostomy). We then cross-validated this list of ICD-9-CM codes in the NIS. MAIN OUTCOMES AND MEASURES Modified Delphi procedure consensus of at least 4 of 5 panelists and proportion agreement in the NIS. RESULTS Among 4,739,522 admissions of patients 65 years and older in the PHC4, a total of 2,569,589 involved a procedure, encompassing 2853 unique procedures. Of 1130 procedures associated with a crude inpatient mortality of at least 1%, 264 achieved consensus as high-risk operations by the modified Delphi procedure. The observed inpatient mortality in the NIS was at least 1% for 227 of 264 procedures (86%) in patients 65 years and older. The pooled inpatient mortality for these identified high-risk procedures performed on patients 65 years and older was double the pooled inpatient mortality for correspondingly identified high-risk operations for patients younger than 65 years (6% vs 3%). CONCLUSIONS AND RELEVANCE We developed a list of procedure codes to identify high-risk surgical procedures in claims data. This list of high-risk operations can be used to standardize the definition of high-risk surgery in quality and outcomes-based studies and to design targeted clinical interventions.
Plastic and Reconstructive Surgery | 2007
W. Bradford Rockwell; Craig A. Hurst; David A. Morton; Alvin C. Kwok; K. Bo Foreman
Background: Arterial grafts are superior to venous grafts when used for microvascular grafting procedures. Advantages of arterial grafts include anatomical taper, improved size match, improved handling characteristics, and superior patency rates. The deep inferior epigastric artery may be used as a source of microvascular graft to replace damaged or diseased arterial segments. By studying cadaver dissections, it is possible to estimate the clinically usable length and caliber of the deep inferior epigastric artery. Methods: Thirty-four preserved cadavers were dissected and 63 deep inferior epigastric arterial systems were removed and measured. The deep inferior epigastric artery was used as an arterial conduit to bypass across nine wrists in eight patients. Results: The mean length from the external iliac artery to the point at which the vessel displayed an external diameter of 1 mm was 14.06 ± 2.54 cm. The deep inferior epigastric artery has been used in nine clinical cases as an arterial conduit to bypass distal to the wrist. All nine bypasses were patent 1 year postoperatively, without donor-site complication. Conclusion: The deep inferior epigastric artery is a morphologically reliable and clinically useful source of arterial grafts.
Journal of Surgical Research | 2015
Alvin C. Kwok; Yue Yung Hu; Christopher M. Dodgion; Wei Jiang; Gladys Ting; Nathan Taback; Stuart R. Lipsitz; Jane C. Weeks; Caprice C. Greenberg
BACKGROUND Invasive procedures are resource intense and may be associated with substantial morbidity. These harms must be carefully balanced with the benefits gained in life expectancy and quality of life. Prior research has demonstrated an increasing aggressiveness of care in cancer patients at the end-of-life. To better characterize surgical care in this setting, we sought to examine trends in the use of invasive procedures in patients diagnosed with metastatic cancer on presentation. MATERIALS AND METHODS Using Surveillance Epidemiology and End Results -Medicare data, we identified invasive procedure claims from 1994-2009 for patients diagnosed with incident stage IV breast, colorectal, lung, and prostate cancer patients in 1995-2006. We grouped procedures into surgically relevant categories, using an adaptation of the Clinical Classifications Software, and measured utilization and relative changes over time. RESULTS Of stage IV patients diagnosed in 2002-2006, 96% underwent a procedure during the course of their cancer care including 63% after the diagnostic period, and 25% in the last month of life. Between 1996 and 2006, minimal change was observed in utilization during the diagnostic period (+1.5%). However, there were significant increases during continuing care (+20.7%) and the last month of life (+21.5%). Procedures consistent with primary tumor resection decreased, whereas those with probable palliative intent and those unrelated to cancer increased. CONCLUSIONS Nearly all patients who present with metastatic cancer undergo invasive procedures. Although overall utilization is increasing, the specific procedure types indicate that it may be appropriate, enhancing the quality of life in this vulnerable population.
Microsurgery | 2017
Alvin C. Kwok; Jayant P. Agarwal
We sought to use the NSQIP database to determine the national rate and predictors of free flap failure based upon flap sites and flap types.