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ABSTRACT: Unintentional hypothermia is a well-described risk factor for death and complications after elective and emergency surgery. The molecular mechanisms by which hypothermia exerts its detrimental effects are not well understood. Differences in cytokine production and the overall cell function have been reported under hypothermic conditions. We investigated the effect of a range of clinically relevant temperatures on cytokine production and microRNA (miRNA) expression in a whole-blood model. We found that there was a wide variation in tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and IL-10 production among different subjects, ranging from low to high TNF-α producers. The intersubject variation can also be found on the transcriptional level: high producers had higher upregulation of TNF-α messenger RNA than intermediate and low producers. This variation in TNF-α was reproducible in each individual. Temperature seems to modulate TNF-α production among these different groups. miRNA expression was modulated by temperature. miRNA-181a might control, or be a part of the mechanism which controls, TNF-α production. However, an analysis of whole-leukocyte RNA does not allow the investigation of mechanisms in a specific leukocyte subpopulation such as monocytes, because these changes may be concealed by miRNA expression changes in the other leukocyte subsets. In conclusion, TNF-α, IL-6, and IL-10 production is highly variable among different persons, but temperature affects the expression of miRNAs, which may consequently alter the production of TNF-α.
Journal of interferon & cytokine research: the official journal of the International Society for Interferon and Cytokine Research 08/2012; 32(10):485-94. · 1.63 Impact Factor
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ABSTRACT: Organ demand exceeds availability of transplantable organs. Organ procurement continues to suffer from failures to identify potential donors, inability to obtain consent for donation, as well as failures to retrieve certain organs as donor demographics change. The purpose of this article is to propose how sequentially introduced measures can increase organ donation rates as well as improve organ procurement.
We analysed the effect of stepwise improvements in the organ procurement process patients in a university-based surgical intensive care unit over a 20-year period. We related newly introduced measures in the organ retrieval process with changes in donation rates. We specifically targeted these three main steps in the donation process: donor identification, conversion of potential donors to actual donors, and organ protection during the procurement process. Finally, we assessed the effect of the same measures on organ procurement after introduction in other hospitals of the same organ procurement region.
Introduction of quality improvement steps increased all of the observed parameters. The number of organ donors was stabilised due to a better identification of potential donors, a major increase in conversion from potential to actual donors, and an increase in extended criteria donor. Improvements in organ protection led to higher rates of organs transplanted per donor and increased recovery of lungs and hearts despite increasing donor age. The same measures were introduced successfully in other hospitals in our organ procurement region.
Sequential improvements in organ procurement can increase the yield of retrieved organs. The same measures can be applied to other hospitals and lead to comparable improvements in organ donation.
Injury 08/2012; 43(11):1805-10. · 1.98 Impact Factor
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ABSTRACT: Process measures constitute the focal point of surgical quality studies. High levels of compliance with such processes have not correlated with improved outcomes. Wide ranges of reported hospital death rates led us to hypothesize that survival after elective colon resection would be a legitimate outcomes measure for quality of surgical practice.
We studied risk-adjusted hospital mortality rates of 85,260 patients in teaching hospitals as reported to the University HealthSystem Consortium (UHC) January 1, 2005 to March 31, 2011. Data were analyzed by institution and surgeon (deidentified). There were 34,504 patients from the HealthCare Utilization Project (HCUP, 2007-2008), who provided a comparison group for nonteaching hospitals. Surgeons with less than 1 year of reported data were excluded.
Elective colon resection mortality rates were densely concentrated around 1.56% for teaching hospitals and at 1.08% for defined surgeons. HCUP data demonstrated a 1.38% nonteaching hospital mortality rate. Neither hospital nor surgeon volume were determinants of mortality, and lower volume entities displayed the widest mortality variations. Among 193 teaching hospitals, there were 6 outliers (4.1%), defined as >2 standard deviations (SDs) above the mean. Similarly, 32 of 681 individual surgeons (4.7%) had a risk-adjusted hospital mortality rate >2SDs above the mean.
Elective colon resection is a safe procedure in both teaching hospitals and nonteaching hospitals, with an impressively homogenous mean mortality rate of 1.56% in teaching hospitals, and 1.38% in nonteaching hospitals. We reject our original hypothesis because the data do not sufficiently discriminate to permit the use of death after elective colon resection as a differentiating quality measure; however, the data do identify individual poor performers. Poor performing institutions/surgeons should seek extramural guidance to improve their outcomes or discontinue performing such operations.
Journal of the American College of Surgeons 03/2012; 214(4):436-43; discussion 443-4. · 4.55 Impact Factor
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ABSTRACT: The goals of this focused meeting were to verify and clarify the causes and extent of the general surgery (GS) workforce shortfalls. We also sought to define workable solutions within the existing framework of medical accreditation and certification.
Numerous peer-reviewed and lay reports describe a current and worsening availability of GS services, affecting rural areas as well as large cities, academia, and the military.
Primary recommendations were broadly agreed upon by attendee surgeons who were selected from numerous different professional scenarios and included 2 nonmedical observers.
Recommendations: (1) enhance the number of GS trainees and the breadth of training, (2) incorporate more flexibility and breadth in residency, (3) minimally invasive surgery should largely return to GS, (4) broader use of community hospitals in these efforts, (5) publicize loan forgiveness and improved visa status for international medical graduates going into GS, and (6) select candidates with a bias toward a general surgical career.
These methods are promising approaches to this serious deficiency but will require regular reporting and publicity for the recording of actual increases in GS output.
Annals of surgery 02/2012; 255(4):611-7. · 7.90 Impact Factor
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ABSTRACT: Lung cancer is the most lethal cancer due to late detection in advanced stages; early diagnosis of lung cancer allows surgical treatment and improves the outcome. The prevalence of gastroesophageal reflux-related adenocarcinomas of the esophagus is increasing; repetitive surveillance endoscopies are necessary to detect development of cancer. A blood-based biomarker would simplify the diagnosis and treatment of both diseases. MicroRNAs (miRNAs) are short RNA strands that interfere with protein production. miRNAs play pivotal roles in cell homeostasis, and dysregulation of miRNAs can lead to the development of cancer. miRNAs can be found in all body fluids and have been proposed to serve as messengers between closely localized cells but also distant organs. Cancer cells actively secrete miRNAs, and these miRNA profiles can be found in blood. We outline, here, how these miRNAs may aid in diagnosis and treatment of lung and esophageal cancers, as well as their apparent limitations.
Seminars in Thoracic and Cardiovascular Surgery 01/2012; 24(3):155-65.
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Surgery 01/2012; 151(1):1-5. · 3.10 Impact Factor
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Annals of surgery 10/2011; 254(4):550-7. · 7.90 Impact Factor
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Hiram C Polk
American journal of surgery 06/2011; 201(6):719-20. · 2.36 Impact Factor
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Annals of surgery 02/2011; 253(2):215-20. · 7.90 Impact Factor
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Canadian journal of surgery. Journal canadien de chirurgie 02/2011; 54(1):67-9. · 1.05 Impact Factor
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ABSTRACT: We sought to determine the effects of altering osmolarity and the reversibility of the detrimental immunologic effects of hypothermia on human monocyte HLA-DR surface expression and reactive oxygen species (ROS) formation.
The effects of altering osmolarity on HLA-DR surface expression and ROS formation were assessed using lipopolysaccharide (LPS)-treated samples treated with either saline, glucose, or mannitol, incubated at 37°C for 2 hours. HLA-DR surface receptor expression and ROS formation were determined after incubation. The effects of the reversibility of hypothermia were measured by incubating LPS-treated samples at 34°C, 37°C, and 40°C for 1 hour. The samples were subsequently rewarmed at 40°C for 1 and 2 hours. The effects of rewarming on HLA-DR surface receptor expression and ROS formation were reassessed.
In the osmolarity experiments, there was a 49% decrease in ROS formation in samples treated with mannitol as compared with saline and glucose. Alterations of osmolarity had no significant effect on HLA-DR surface expression. In the rewarming experiments, rewarming for either 1 or 2 hours abolished any significant differences in HLA-DR surface expression and ROS formation between samples preincubated at the different temperatures.
The presumed inert mannitol was found to significantly decrease ROS formation, but had no effect on HLA-DR surface expression. In addition, the effects of hypothermia on HLA-DR surface expression or ROS formation may be better reversed within 2 hours than in 1 hour.
Journal of the American College of Surgeons 02/2011; 212(2):180-6. · 4.55 Impact Factor
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Hiram C Polk
American journal of surgery 01/2011; 201(1):84. · 2.36 Impact Factor
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ABSTRACT: The numbers of unanswered questions are many. Can intraoperative application, such as topical antimicrobial use in pulsed lavage, reduce the microbial burden on the wound interface before closure? Can closed suction drains within the closed surgical incision reduce infection rates, especially in patients with a large body mass index? What is the role of delayed primary closure or secondary closure in the wound where obvious contamination has occurred, or in the circumstance of emergent colonic resection where considerable contamination is encountered from preexistent perforation? Should immediate negative-pressure wound dressings be applied in the open contaminated wound? These and many other questions still confront the surgeon in the challenge of the surgical wound in major colorectal surgery.
Advances in Surgery 01/2011; 45:131-40.
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Journal of the American College of Surgeons 10/2010; 211(4):558-60. · 4.55 Impact Factor
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ABSTRACT: Recent clinical trials investigating the role of hyperoxia in decreasing surgical site infection have reported conflicting results. Immunologic mechanisms through which supplemental oxygen could act have not been elucidated fully. The authors sought to investigate the effects of hyperoxia on previously tested and prognostically significant innate immune parameters to uncover the potential effects of hyperoxia at the cellular level.
After formal approval and informed consent, venous blood samples were collected from young healthy volunteers. Corresponding samples were incubated at 21 or 80% O2 following a 1 ng/ml lipopolysaccharide challenge and analyzed to determine human leukocyte antigen-DR surface receptor expression, cytokine release, phagocytic capacity, and formation of reactive oxygen species. Data are presented as mean +/- SD.
After the 2 h of incubation at 21% O2 (room air) and in 80% O2 chambers, the change in human leukocyte antigen-DR mean channel fluorescence in lipopolysaccharide-stimulated monocytes was 2,177 +/- 383 and 2,179 +/- 338 (P = 0.96), respectively. Tumor necrosis factor-alpha concentrations were significantly lower for samples incubated at 80% O2 when compared with 21% O2 (P < 0.05). The phagocytic capacity of the innate immune system was not significantly enhanced by supplemental oxygen. However, the formation of reactive oxygen species increased by 87% (P < 0.05).
Hyperoxia exerts significant effects on multiple cellular and immunologic parameters, providing a potential mechanism for benefits from the use of supplemental oxygen. However, the ability to translate positive basic scientific findings to the operating suite or bedside require the existence of similar innate immune processes in vivo and the efficient transfer of oxygen to the sites where it may be used.
Anesthesiology 08/2010; 113(2):369-77. · 5.36 Impact Factor
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Hiram C Polk
American journal of surgery 07/2010; 200(1):81. · 2.36 Impact Factor
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ABSTRACT: Most studies of surgical quality improvement have been performed in large and/or teaching hospitals; the efficacy of safety and quality efforts in smaller hospitals have not been reported.
Four smaller hospitals joined a collaborative to study process measures through an expanded surgical time-out and some outcomes. The data were collected in real time.
Well-performing hospitals (all 4) improved further but variably. Gynecologic and orthopedic surgeons performed more consistently in most measures than did general surgeons.
These small hospitals readily accepted a time-out-based real-time data collection and with their surgical staff improved in most parameters.
American journal of surgery 07/2010; 200(1):90-6. · 2.36 Impact Factor
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ABSTRACT: Surgical quality measures have room for improvement in both large- and small-town hospitals.
We sought concurrence of surgical specialists (general, orthopedic, gynecologic) to study accepted quality and safety parameters using a surgical time-out-based platform.
Surgeons and hospitalists participated promptly and actively and recorded enhanced performance measures compared with prior work and within the period of study. Practice patterns varied, and interchange among participating hospitals was helpful.
Smaller institutions are more nimble than larger ones and developed interchangeable ideas for improvement. Surgical process measures improved such that all 4 hospitals are concerned about and committed to maintaining the gains.
American journal of surgery 07/2010; 200(1):97-104. · 2.36 Impact Factor
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ABSTRACT: Surgical safety and quality initiatives have now moved to the front of the agenda for contemporary surgery.
Sixty-two surgical specialists began to study quality and cost control in 1998, and those efforts grew into a Centers for Medicare and Medicaid Services-funded pilot study of the Surgical Care Improvement Project in 2004. Subsequent symposia and studies evolved.
A greater awareness of the issues and methods for meaningful improvement of surgical safety in nearly 25,000 specialty surgeries have been described in numerous peer-reviewed publications.
Surgeon-initiated efforts have led to marked improvements in multiple specialties and in many small and large hospitals and academic training centers.
American journal of surgery 07/2010; 200(1):82-9. · 2.36 Impact Factor
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ABSTRACT: Factors such as temperature, oxygen, and glucose have recently been implicated in the development of surgical sepsis by either promoting or attenuating protective components of the innate immune response. Reducing infective sequelae and the improvement of the quality of care of surgical patients is a top practice priority today. These factors and their associated effects are discussed through the examination of recent clinical and scientific studies to provide an up-to-date evidence-based review.
The American surgeon 06/2010; 76(6):571-7. · 1.28 Impact Factor
