Single and binary ion sorption equilibria of monovalent and divalent ions in commercial ion exchange membranes

The co-ion and counter-ion sorption of monovalent (Na⁺, K⁺, Cl^- and NO₃^-) and divalent ions (Ca²⁺ and SO₄^2-) in commercial Neosepta ion exchange membranes were systemically studied in both single and binary salt systems. The new generation of Neosepta cation exchange membrane (CSE) showed a significant difference in water uptake and co-ion sorption compared to the earlier generation (CMX). Use of the Manning model confirmed that there were significant differences between these membranes, with the estimated value of the Manning parameter changing from 1.0 ± 0.1 for CMX to 2.8 ± 0.5 for CSE. There were fewer differences between the two Neosepta anion exchange membranes, AMX and ASE. In single salt solutions, potassium sorbed most strongly into the cation exchange membranes, but in binary salt mixtures, calcium dominated due to Donnan exclusion at low concentrations. While these trends were expected, the sorption behaviour in the anion exchange membranes was more complex. The water uptake of both AMX and ASE was shown to be the greatest in Na₂SO₄ solutions. This strong water uptake was reflected in strong sorption of sulphate ions in a single salt solution. Conversely, in a binary salt mixture with NaCl, sulphate sorption fell significantly at higher concentrations. This was possibly caused by ion pairing within the solution, as well as the strongly hydrophobic nature of styrene in the charged polymer. Water uptake was lowest in NaNO₃ solutions, even though sorption of the nitrate ion was comparable to that of chloride in these single salt solutions. In the binary mixture, nitrate was absorbed more strongly than chloride. These results could be due to the low surface charge density of this ion allowing it to bond more strongly with the hydrophobic polymeric backbone at the exclusion of water and other ions.

Tracheostomy Update: When and How

Tracheostomy remains one of the most commonly performed surgical procedures in the setting of acute respiratory failure. Tracheostomy literature focuses on 2 aspects of this procedure: when (timing) and how (technique). Recent trials have failed to demonstrate an effect of tracheostomy timing on most clinically important endpoints. Nonetheless, relative to continued translaryngeal intubation, studies suggest that tracheostomy use is associated with less need for sedation and enhanced patient comfort. Evidence likewise suggests that percutaneous dilational tracheostomy is advantageous with respect to cost and complication profile and should be considered the preferred approach in appropriately selected patients.

Risk Factors for In-Hospital Mortality in Smoke Inhalation-Associated Acute Lung Injury: Data From 68 United States Hospitals

BACKGROUND

Mortality after smoke inhalation-associated acute lung injury (SI-ALI) remains substantial. Age and burn surface area are risk factors of mortality, whereas the impact of patient- and center-level variables and treatments on survival are unknown.

METHODS

We performed a retrospective cohort study of burn and non-burn centers at 68 US academic medical centers between 2011 and 2014. Adult inpatients with SI-ALI were identified using an algorithm based on a billing code for respiratory conditions from smoke inhalation who were mechanically ventilated by hospital day 4, with either a length-of-stay ≥ 5 days or death within 4 days of hospitalization. Predictors of in-hospital mortality were identified using logistic regression. The primary outcome was the odds ratio for in-hospital mortality.

RESULTS

A total of 769 patients (52.9 ± 18.1 years) with SI-ALI were analyzed. In-hospital mortality was 26% in the SI-ALI cohort and 50% in patients with ≥ 20% surface burns. In addition to age > 60 years (OR 5.1, 95% CI 2.53-10.26) and ≥ 20% burns (OR 8.7, 95% CI 4.55-16.75), additional risk factors of in-hospital mortality included initial vasopressor use (OR 5.0, 95% CI 3.16-7.91), higher diagnostic-related group-based risk-of-mortality assignment and lower hospital bed capacity (OR 2.3, 95% CI 1.23-4.15). Initial empiric antibiotics (OR 0.93, 95% CI 0.58-1.49) did not impact survival. These new risk factors improved mortality prediction by 9.9% (P < .001).

CONCLUSIONS

In addition to older age and major surface burns, mortality in SI-ALI is predicted by initial vasopressor use, higher diagnostic-related group-based risk-of-mortality assignment, and care at centers with < 500 beds, but not by initial antibiotic therapy.

Is It Time to Rethink Postgraduate Training Requirements for Licensure?

Approaches to postgraduate medical training have evolved substantially in recent years, reflecting the complexity of the educational mission. Residency programs seek to produce clinicians who achieve board certification as an attestation of their competency. Certification criteria are established by the American Board of Medical Specialties, are consistent from state to state, and include periods of supervised instruction ranging from as few as three years (for primary care specialties) to much longer for selected disciplines. In contrast, minimum postgraduate training criteria necessary for licensure as an independent practitioner are established by state medical boards and vary significantly among and within jurisdictions. In most states, licenses can be granted to individuals who have completed as little as one year of postgraduate training. The discrepancy between the minimum time commitment necessary to become a competent physician and that to be licensed as an independent practitioner has implications for health care quality and safety. Data are lacking as to the number of licenses issued nationally to individuals who have only partially completed residency training and the nature of practices they pursue. Extrapolating from available evidence, these individuals may very well provide care inferior to those who have satisfied training requirements for certification eligibility and be more prone to problematic behavior resulting in disciplinary action. Efforts to establish more rigorous licensure criteria will require dialog between members of the academic community, professional organizations, state medical boards, and legislatures. The recently proposed Interstate Medical Licensure Compact may serve as a prototype for achieving this goal.

Does difficulty functioning in the surrogate role equate to vulnerability in critical illness research? Use of path analysis to examine the relationship between difficulty providing substituted judgment and receptivity to critical illness research participation

PURPOSE

Individuals who struggle to provide substitute judgment for the critically ill often find it challenging to engage in decision making for therapeutic interventions. Although essential to the conduct of research, how these individuals respond to requests for clinical trial participation is poorly understood.

METHODS

Survey data collected to examine surrogate attitudes toward research provided the conceptual framework to explore influences on decision making. Path analysis was used to derive the final model (nonlatent, fully recursive, 1 indicator/variable).

RESULTS

Surrogates with list-wise complete records (406) were analyzed. The following variables were not retained in the final model: education, income, religiosity, decision-making experience, discussion of patient's wishes, number of individuals assisting with decision making, trust in care providers, difficulty making decisions, and responsibility for decision making. Being white and having experience making treatment decisions for the patient during the current intensive care unit encounter affected the likelihood the surrogate would permit participation in research positively (parameter estimates, 0.281 and 0.06, respectively). No variable reflecting difficulty functioning in the surrogate role was associated with permitting research participation.

CONCLUSIONS

We were unable to demonstrate a relationship between perceived difficulty in decision making in the surrogate role and receptivity to clinical trial participation.

Surrogate receptivity to participation in critical illness genetic research: aligning research oversight and stakeholder concerns

BACKGROUND

Collection of genetic biospecimens as part of critical illness investigations is increasingly commonplace. Oversight bodies vary in restrictions imposed on genetic research, introducing inconsistencies in study design, potential for sampling bias, and the possibility of being overly prohibitive of this type of research altogether. We undertook this study to better understand whether restrictions on genetic data collection beyond those governing research on cognitively intact subjects reflect the concerns of surrogates for critically ill patients.

METHODS

We analyzed survey data collected from 1,176 patients in nonurgent settings and 437 surrogates representing critically ill adults. Attitudes pertaining to genetic data (familiarity, perceptions, interest in participation, concerns) and demographic information were examined using univariate and multivariate techniques.

RESULTS

We explored differences among respondents who were receptive (1,333) and nonreceptive (280) to genetic sample collection. Whereas factors positively associated with receptivity to research participation were "complete trust" in health-care providers (OR, 2.091; 95% CI, 1.544-2.833), upper income strata (OR, 2.319; 95% CI, 1.308-4.114), viewing genetic research "very positively" (OR, 3.524; 95% CI, 2.122-5.852), and expressing "no worry at all" regarding disclosure of results (OR, 2.505; 95% CI, 1.436-4.369), black race was negatively associated with research participation (OR, 0.410; 95% CI, 0.288-0.585). We could detect no difference in receptivity to genetic sample collection comparing ambulatory patients and surrogates (OR, 0.738; 95% CI, 0.511-1.066).

CONCLUSIONS

Expressing trust in health-care providers and viewing genetic research favorably were associated with increased willingness for study enrollment, while concern regarding breach of confidentiality and black race had the opposite effect. Study setting had no bearing on willingness to participate.

Perspectives of Decisional Surrogates and Patients Regarding Critical Illness Genetic Research

BACKGROUND

Critical illness research is challenging due to disease severity and because patients are frequently incapacitated. Surrogates called upon to provide consent might not accurately represent patient preferences. Though commonplace, genetic data collection adds complexity in this context. We undertook this investigation to understand whether surrogate decision makers would be receptive to permitting participation in a critical illness genetics study and whether their decision making was consistent with that of the patient represented.

METHODS

We invited individuals identified as surrogates for critically ill adults, if required, as well as patients once recovered to participate in a survey designed to understand attitudes about genetic research. Associations between dependent (receptivity to participation, concordance of responses) and independent variables were tested using bivariate and multivariate logistic regression analyses.

RESULTS

Most of the entire surrogate sample (n=439) reported familiarity with research, including genetic research; tended to view research as useful; and were receptive to allowing their family member participate (with 39.6% and 38.1% stating that this would be "very" and "somewhat likely," respectively) even absent direct benefit. Willingness to participate was similar comparing genetic and non-genetic studies (χ² [1,n=439]=0.00127, p=0.972), though respondents expressed worry regarding lack of confidentiality of genetic data. Responses were concordant in 70.8% of the 192 surrogate-patient pairs analyzed. In multivariate analysis, African American race was associated with less receptivity to genetic data collection (p<0.05). No factors associated with concordance of surrogate-patient response were identified.

CONCLUSIONS

Surrogates' receptivity to critical illness research was not influenced by whether the study entailed collection of genetic data. While more than two-thirds of surrogate-patient responses for participation in genetics research were concordant, concerns expressed regarding genetic data often related to breach of confidentiality. Emphasizing safeguards in place to minimize such breeches might prove an effective strategy for enhancing recruitment.

A computer-based education intervention to enhance surrogates' informed consent for genomics research

BACKGROUND

Many research studies conducted today in critical care have a genomics component. Patients' surrogates asked to authorize participation in genomics research for a loved one in the intensive care unit may not be prepared to make informed decisions about a patient's participation in the research.

OBJECTIVES

To examine the effectiveness of a new, computer-based education module on surrogates' understanding of the process of informed consent for genomics research.

METHODS

A pilot study was conducted with visitors in the waiting rooms of 2 intensive care units in a Midwestern tertiary care medical center. Visitors were randomly assigned to the experimental (education module plus a sample genomics consent form; n = 65) or the control (sample genomics consent form only; n = 69) group. Participants later completed a test on informed genomics consent.

RESULTS

Understanding the process of informed consent was greater (P = .001) in the experimental group than in the control group. Specifically, compared with the control group, the experimental group had a greater understanding of 8 of 13 elements of informed consent: intended benefits of research (P = .02), definition of surrogate consenter (P= .001), withdrawal from the study (P = .001), explanation of risk (P = .002), purpose of the institutional review board (P = .001), definition of substituted judgment (P = .03), compensation for harm (P = .001), and alternative treatments (P = .004).

CONCLUSIONS

Computer-based education modules may be an important addition to conventional approaches for obtaining informed consent in the intensive care unit. Preparing patients' family members who may consider serving as surrogate consenters is critical to facilitating genomics research in critical care.

Exploring determinants of surrogate decision-maker confidence: an example from the ICU

This article is an exploratory data analysis of the determinants of confidence in a surrogate decision maker who has been asked to permit an intensive care unit (ICU) patient's participation in genetic research. We pursue the difference between surrogates' and patients' confidence that the surrogate can accurately represent the patient's wishes. The article also explores whether greater confidence leads to greater agreement between patients and surrogates. Our data come from a survey conducted in three hospital ICUs. We interviewed 445 surrogates and 214 patients. The only thing that influences patients' confidence in their surrogate's decision is whether they had prior discussions with him or her; however, there are more influences operating on the surrogate's self-confidence. More confident surrogates are more likely to match their patients' wishes. Patients are more likely to agree to research participation than their surrogates would allow. The surrogates whose response did not match as closely were less trusting of the hospital staff, were less likely to allow patient participation if there were no direct benefits to the patient, had given less thought about the way genetic research is conducted, and were much less likely to have a person in their life who they would trust to make decisions for them if they were incapacitated.

Critical illness research involving collection of genomic data: the conundrum posed by low levels of genomic literacy among surrogate decision makers for critically ill patients

Critical illness clinical trials that entail genomic data collection pose unique challenges. In this qualitative study, we found that surrogate decision makers (SDMs) for critically ill individuals, such as those who would be approached for study participation, appeared to have a limited grasp of genomic principles. We argue that low levels of genomic literacy should neither preclude nor be in conflict with the conduct of ethically rigorous clinical trials.

Factors affecting stress experienced by surrogate decision makers for critically ill patients: implications for nursing practice

OBJECTIVES

This study explores surrogate decision-makers' (SDMs) challenges making decisions related to the care of patients in critical care, to (1) characterise the SDM stress, (2) identify personal, social, care-related factors influencing stress and (3) consider implications of findings to improving critical care practice.

METHODOLOGY

Semi-structured interviews were conducted with SDMs of critically ill patients receiving care in two tertiary care institutions. Transcripts were analysed using a grounded theory approach. Domains explored were: stress characteristics, stress mitigators, coping strategies, social networks, SDM decision-making role, decision-making concordance, knowledge of patient's preferences, experience with provider team, SDM-provider communication, patient outcome certainty.

MAIN OUTCOMES

We interviewed 34 SDMs. Most were female and described long-term relationships with patients. SDMs described the strain of uncertain outcomes and decision-making without clear, consistent information from providers. Decision-making anxiety was buffered by SDMs' active engagement of social networks, faith and access to clear communication from providers.

CONCLUSION

Stress is a very real factor influencing SDMs confidence and comfort making decisions. These findings suggest that stress can be minimised by improving communication between SDMs and medical providers. Nurses' central role in the ICU makes them uniquely poised to spearhead interventions to improve provider-SDM communication and reduce SDM decision-making anxiety.

High resource utilization does not affect mortality in acute respiratory failure patients managed with tracheostomy

BACKGROUND

Tracheostomy practice in patients with acute respiratory failure (ARF) varies greatly among institutions. This variability has the potential to be reflected in the resources expended providing care. In various healthcare environments, increased resource expenditure has been associated with a favorable effect on outcome.

OBJECTIVE

To examine the association between institutional resource expenditure and mortality in ARF patients managed with tracheostomy.

METHODS

We developed analytic models employing the University Health Systems Consortium (Oakbrook, Illinois) database. Administrative coding data were used to identify patients with the principal diagnosis of ARF, procedures, complications, post-discharge destination, and survival. Mean resource intensity of participating academic medical centers was determined using risk-adjusted estimates of costs. Mortality risk was determined using a multivariable approach that incorporated patient-level demographic and clinical variables and institution-level resource intensity.

RESULTS

We analyzed data from 44,124 ARF subjects, 4,776 (10.8%) of whom underwent tracheostomy. Compared to low-resource-intensity settings, treatment in high-resource-intensity academic medical centers was associated with increased risk of mortality (odds ratio 1.11, 95% CI 1.05-1.76), including those managed with tracheostomy (odds ratio high-resource-intensity academic medical center with tracheostomy 1.10, 95% CI 1.04-1.17). We examined the relationship between complication development and outcome. While neither the profile nor number of complications accumulated differed comparing treatment environments (P > .05 for both), mortality for tracheostomy patients experiencing complications was greater in high-resource-intensity (95/313, 30.3%) versus low-resource-intensity (552/2,587, 21.3%) academic medical centers (P < .001).

CONCLUSIONS

We were unable to demonstrate a positive relationship between resource expenditure and outcome in ARF patients managed with tracheostomy.

Real-time perspectives of surrogate decision-makers regarding critical illness research: findings of focus group participants

OBJECTIVE

We undertook the current investigation to explore how the pressures of serving as a surrogate decision-maker (SDM) for an acutely ill family member influence attitudes regarding clinical investigation.

METHODS

We conducted a prospective study involving SDMs for critically ill patients cared for in the ICUs of two urban hospitals. Measurements included participation in focus groups designed to explore perceptions of ICU care and clinical research. Audiotapes were transcribed and analyzed to identify common patterns and themes using grounded theory. Demographic and clinical data were summarized using standard statistical methods.

RESULTS

Seventy-four SDMs (corresponding to 24% of eligible patients) participated. Most SDMs were women and described long-term relationships with the patients represented. SDMs described their role as "overwhelming," their emotions were accentuated by the fatigue of the ICU experience, and they relied on family members, social contacts, and religion as sources of support. Altruism was reported as a common motivation for potential study participation, a sentiment often strengthened by the critical illness episode. Although research was viewed as optional, some SDMs perceived invitation for research participation as tacit acknowledgment of therapeutic failure. SDMs expressed a preference for observational studies (perceived as low risk) over interventional designs (perceived as higher risk). Trust in the ICU team and the research enterprise seemed tightly linked.

CONCLUSIONS

Despite significant emotional duress, SDMs expressed interest in investigation and described multiple factors motivating participation. Consent processes that minimize the effects of anxiety may be one strategy to enhance recruitment.

Video review using a reliable evaluation metric improves team function in high-fidelity simulated trauma resuscitation

OBJECTIVE

To demonstrate that instruction of proper team function can occur using high-fidelity simulated trauma resuscitation with video-assisted debriefing and that this process can be integrated rapidly into a standard general surgery curriculum.

DESIGN

The rater reliability of our team metric was assessed by having physicians and nonphysicians rate the same video-recorded trauma simulations at intervals in time. To assess the effectiveness of video debriefing, subjects participated in a 3-week trauma team training course that consisted of 2 video-recorded simulation sessions, each approximately 2 hours in length separated by a 90-minute debriefing session. To assess the impact of the debriefing session, video recordings of participants performing resuscitations before and after the debriefing were reviewed by a panel of blinded traumatologists and graded using our team evaluation instrument.

SETTING

The study took place at the high-fidelity simulation center at a large, urban academic training hospital.

PARTICIPANTS

All 11 PGY-2 general surgery and combined general surgery and plastic surgery residents at our institution.

RESULTS

Our instrument was found to have high interrater correlation (interclass correlation coefficient [ICC], 0.926; 95% confidence interval, 0.893-0.953). Initially, residents were either unsure as to their competency to serve as team leader (70%) or felt they were not competent to serve as team leader (30%). Ninety percent of residents found the video debriefing very to extremely helpful in improving team function and clinical competency. All participants felt more competent as both team leaders and team members because of the video debriefing. The mean team function score improved significantly after video debriefing (4.39 [±0.3] vs 5.45 [±0.4] prevideo vs postvideo review, p < 0.05).

CONCLUSIONS

Video review with debriefing is an effective means of teaching team competencies and improving team function in simulated trauma resuscitation. This strategy can be integrated readily into the surgical curriculum analogous to other applications of simulation technology.

Considerations in the construction of an instrument to assess attitudes regarding critical illness gene variation research

Clinical studies conducted in intensive care units are associated with logistical and ethical challenges. Diseases investigated are precipitous and life-threatening, care is highly technological, and patients are often incapacitated and decision-making is provided by surrogates. These investigations increasingly involve collection of genetic data. The manner in which the exigencies of critical illness impact attitudes regarding genetic data collection is unstudied. Given interest in understanding stakeholder preferences as a foundation for the ethical conduct of research, filling this knowledge gap is timely. The conduct of opinion research in the critical care arena is novel. This brief report describes the development of parallel patient/surrogate decision-maker quantitative survey instruments for use in this environment. Future research employing this instrument or a variant of it with diverse populations promises to inform research practices in critical illness gene variation research.

Ethical considerations in the collection of genetic data from critically ill patients: what do published studies reveal about potential directions for empirical ethics research?

Critical illness trials involving genetic data collection are increasingly commonplace and pose challenges not encountered in less acute settings, related in part to the precipitous, severe and incapacitating nature of the diseases involved. We performed a systematic literature review to understand the nature of such studies conducted to date, and to consider, from an ethical perspective, potential barriers to future investigations. We identified 79 trials enrolling 24 499 subjects. Median (interquartile range) number of participants per study was 263 (116.75-430.75). Of these individuals, 16 269 (66.4%) were Caucasian, 1327 (5.4%) were African American, 1707 (7.0%) were Asian Pacific Islanders and 139 (0.6%) were Latino. For 5020 participants (20.5%), ethnicity was not reported. Forty-eight studies (60.8%) recruited subjects from single centers and all studies examined a relatively small number of genetic markers. Technological advances have rendered it feasible to conduct clinical studies using high-density genome-wide scanning. It will be necessary for future critical illness trials using these approaches to be of greater scope and complexity than those so far reported. Empirical research into issues related to greater ethnic inclusivity, accuracy of substituted judgment and specimen stewardship may be essential for enabling the conduct of such trials.

Examination of non-clinical factors affecting tracheostomy practice in an academic surgical intensive care unit

OBJECTIVES

To gain insight into nonclinical factors potentially influencing tracheostomy practice and determine whether a specialized consultation form impacts tracheostomy utilization.

DESIGN

Prospective, observational.

SETTING

Surgical intensive care unit (SICU).

PATIENTS

Patients requiring mechanical ventilatory support. Data abstracted from the Project Impact administrative database served as a practice benchmark.

INTERVENTIONS

Prospective data collection, completion of online survey, and implementation of specialized tracheostomy consultation form.

MEASUREMENTS AND MAIN RESULTS

Data were prospectively collected on 539 patients and 13 attending intensivists. Our SICU tracheostomy rate (54.2%) exceeded that of 18 comparable ICUs participating in Project Impact (13.9%, p < .001). We attempted to identify factors that might account for liberal tracheostomy use. In 41.5% (+/-0.6%) of patients undergoing tracheostomy, extubation had not occurred despite successful completion of spontaneous breathing trial on >or=1 occasion, a rate that varied significantly among attending intensivists responsible for decision making for this procedure (p < .001). Attending intensivists and postgraduate surgical trainees with SICU experience were surveyed to better understand perceptions of tracheostomy practice. Most respondents (96.1%) reported relying on spontaneous breathing trial to guide decision for extubation, 72.6% estimated that <or=25% of patients successfully completed spontaneous breathing trial but did not proceed to immediate extubation, 86.3% estimated that <or=25% of such patients undergo tracheostomy, and 58.8% felt an acceptable benchmark for this practice was <or=10%. In most survey domains, respondents' perceptions underestimated actual practice. Implementation of a specialized tracheostomy consultation form did not impact tracheostomy utilization.

CONCLUSIONS

We identified variation among clinicians with respect to tracheostomy practice as well as discrepancies between perceptions of this practice and actual utilization. These factors may underlie the liberal use of this procedure in our SICU. Processes for providing accurate physician feedback may assist in optimizing tracheostomy use.

Team behavior during trauma resuscitation: a simulation-based performance assessment

INTRODUCTION

Trauma resuscitations require a coordinated response from a diverse group of health care providers. Currently, there are no widely accepted methods of assessing team effectiveness in this setting. Simulation affords a method to assess team effectiveness. The purpose of this study was to use a simulation setting to develop a specialized assessment instrument for team response in trauma resuscitation.

METHODS

We developed our assessment instrument using clinical simulation. Four teams of 3 postgraduate year-2 surgical trainees in conjunction with scripted confederates were videotaped enacting 6 separate trauma resuscitation scenarios that mirrored clinical conditions encountered at our level 1 trauma center. Ten of the resulting videotaped scenarios represented a spectrum of team behavior (ineffective to effective) and were scored by 8 experienced clinicians using the Mayo High Performance Teamwork Scale.

RESULTS

Based in part on the Mayo High Performance Teamwork Scale, we created a prototype trauma team assessment tool consisting of 7 attributes that we scored in binary fashion (present/absent). We validated this prototype by assigning a normalized ranking score to each of the 10 scenarios based on the score supplied by each rater. The presence/absence of the 7 attributes varied significantly among scenarios (52.5% to 93.8%; P < .001). Median scores differed significantly comparing the 5 lowest-ranking scenarios with the 5 highest-ranking scenarios (P < .001).

CONCLUSION

Our prototype instrument may be effective at assessing team effectiveness during trauma resuscitations. This instrument may prove useful for assessing team competency skills, providing timely feedback to teams, and examining the relationship between effective team function and clinically important outcomes. Further, it may be applicable to other high-acuity, time-sensitive clinical situations.

Implementation of an "after hours" resident educational program in a general surgery residency: a paradigm for increasing formal didactic training outside of the hospital setting in the era of the 80-hour workweek

INTRODUCTION

Residency programs have been forced to curtail many educational activities to comply with duty-hour restrictions. We describe an "after hours" educational program as a forum to provide small-group education customized for each training level to compliment our formal curriculum.

METHODS

Sessions within each general surgery specialty were organized such that 1 session each month was open to either junior (R1 and R2) or senior (R3-R5) trainees and hosted by surgical faculty. Attendance was optional and limited to 15 residents per session with the format determined by the hosting faculty. Participants completed a postsession survey.

RESULTS

Fourteen sessions were held during the 2008-2009 academic year. All sessions were >90% subscribed within 1 week of announcement and attendance was 88%. The average session duration was 2.6 +/- 0.4 hours. Junior resident sessions focused on preparing R1 and R2 residents to handle common consult questions; senior resident sessions were modeled as "mock oral boards." Resident and faculty responses to the postsession questionnaire were similar and favorable with respect to the educational value of this format.

CONCLUSIONS

There is enthusiasm among faculty and trainees to provide small-group, level-specific educational programs outside of the hospital setting and the 80-hour workweek. Such a program is easily implemented, highly effective, and well received. This format has the added benefit of improving interaction between faculty and residents and increasing the camaraderie of a surgical training program.

Surrogate consent for genomics research in intensive care

Surrogate decision makers may be poorly prepared to give informed consent for genomics research for their loved ones in intensive care. A review of the challenges and strategies associated with obtaining surrogates' consent for genomics research in intensive care patients revealed that few well-controlled studies have been done on this topic. Yet, a major theme in the literature is the role of health care professionals in guiding surrogates through the informed consent process rather than simply witnessing a signature. Informed consent requires explicit strategies to approach potential surrogates effectively, educate them, and ensure that informed consent has been attained.

Pharmacoepidemiology of QT-interval prolonging drug administration in critically ill patients

PURPOSE

Commonly prescribed medications produce QT-prolongation and are associated with torsades de pointes in non-acutely ill patients. We examined patterns of QT-prolonging drug use in critically ill individuals.

METHODS

An administrative critical care database was utilized to identify patients receiving drugs associated with QT-interval prolongation or torsades de pointes for > or = 24 hours.

RESULTS

Data from 212 016 individuals collected over a 63-month period was examined to identify 6125 patients (2.9%) receiving QT-interval prolonging drugs. These individuals had a mean (+/-SE) age of 63.0 (+/-0.2) years, were predominately male (55.4%) and Caucasian (84.4%), and were exposed to QT-interval prolonging agents for a mean (+/-SE) 53.1 (+/-0.4)% of their ICU length of stay. Respiratory and cardiovascular illnesses were the most common reasons for ICU admission (17.2, 12.0%, respectively). The most frequently administered agents were amiodarone (23.5%), haloperidol (19.8%), and levofloxacin (19.7%); no other single agent accounted for more than 10% of QT-interval prolonging drugs prescribed. Coadministration of QT-prolonging drugs occurred in 1139 patients (18.6%). These patients had higher ICU mortality rate and longer ICU lengths of stay, compared to patients not receiving coadministered drugs (p < 0.001 for both). For patients receiving coadministered drugs, overlap occurred for 71.4 (+/-0.8)% of the time that the drugs were given. Amiodarone coadministration with antibiotics, haloperidol coadministration with antibiotics, and haloperidol coadministration with amiodarone, comprised 15.2, 13.7, and 9.4%, of all coadministered agents, respectively.

CONCLUSIONS

QT-prolonging drugs were used in a minority of critically ill patients. Prospective evaluation in the ICU environment is necessary to determine whether administration of these agents is associated with adverse cardiac events comparable to those reported in ambulatory patients.

Anonymous group peer review in surgery morbidity and mortality conference

BACKGROUND

Surgical peer review might be characterized by assessment heterogeneity.

METHODS

We performed a prospective, anonymous, peer review of surgeon and system performance during a morbidity and mortality conference.

RESULTS

Twenty-two cases were reviewed by a mean of 48.9 respondents each, including attendings, fellows, and residents. A mean of 50% (standard deviation, 23%) of respondents identified some quality issue in each case, reflecting high heterogeneity. The mean percentage in identifying a system issue was 27%, and in identifying a physician issue was 37%. When identifying a physician issue, physician care was judged as appropriate by 72%, as controversial by 26%, or as inappropriate by 2%. Residents were more likely than attendings to identify system issues (odds ratio, 2.23) and physician issues (odds ratio, 3.58), but attendings were more likely to rate care controversial or inappropriate (odds ratio, 2.53).

CONCLUSIONS

Surgical peer reviews, even after group discussion, display substantial heterogeneity. Review methods should account for this heterogeneity.

Molecular Simulation and Experimental Study of Substituted Polyacetylenes: Fractional Free Volume, Cavity Size Distributions and Diffusion Coefficients

Glassy, disubstituted acetylene-based polymers exhibit extremely high gas permeabilities and high vapor/gas selectivities, which is quite unusual for conventional glassy polymers such as polysulfone. Diffusion coefficients of poly[1-phenyl-2-[p-(trimethylsilyl)phenyl]acetylene] (PTMSDPA) and poly[diphenylacetylene] (PDPA) were obtained using both molecular simulation and experimental techniques. PTMSDPA, a disubstituted glassy acetylene-based polymer, exhibits higher diffusivity than its desilylated analogue, PDPA. Simulation results are in good agreement with experimental data. Cavity size (free volume) distributions of both polymers are also obtained using an energetic-based algorithm (in't Veld et al., J. Phys. Chem. B 2000, 104, 12028) developed recently. Larger cavities in PTMSDPA contribute to its higher diffusivity, and higher permeability.

Genetic research and testing in critical care: surrogates' perspective

OBJECTIVE

Genetic testing is increasingly a component of clinical research in critical illness and has potential for integration into routine care. This study explored the perspectives of surrogate decision-makers (SDMs) for acutely ill patients with respect to social, legal, and ethical aspects of genetic testing.

SETTING

Medical and surgical intensive care units in an urban tertiary care hospital.

INTERVENTION

Questionnaires administered to SDMs for critically ill patients over a 12-month period.

MEASUREMENTS AND MAIN RESULTS

A majority of eligible SDMs participated (117/146; 80.8%). SDMs were more likely to permit genetic testing for purposes of diagnosing a treatable life-threatening disease (114/117; 97.4%) or chronic disease (111/117; 94.9%) than for an untreatable life-threatening illness (95/117; 81.2%) (p < .001). SDMs were receptive to testing to explain familial traits (112/117; 95.7%) or ethnic traits (105/117; 89.7%) (p = .131). SDMs were concerned about potential for economic discrimination, with a majority expressing reluctance to permit testing if employers (93/117; 79.5%), health insurers (90/117; 76.9%), or life insurers (92/117; 78.6%) could access results. There was a greater willingness to allow participation in studies in which data were collected anonymously (90/117; 76.9%) vs. nonanonymously (75/117; 64.1%) (p = .04). Finally, SDMs placed greater trust in universities and nonprofit organizations (107/117; 91.4%) than either the federal government (75/117; 64.1%) or pharmaceutical companies (46/117; 39.3%) to perform genetic research (p < .01).

CONCLUSIONS

SDMs expressed concerns regarding economic discrimination, confidentiality of data, and trust in entities conducting clinical investigation that may represent barriers both to performing studies in which genetic information is collected and to implementation of gene-based technologies in the critical care environment.

Relationship between tracheostomy timing and duration of mechanical ventilation in critically ill patients

OBJECTIVE

Tracheostomy practice in the setting of critical illness is controversial because evidence demonstrating unequivocal benefit is lacking. We undertook this study to determine the relationship between tracheostomy timing and duration of mechanical ventilation, intensive care unit length of stay, and hospital length of stay and to evaluate the relative influence of clinical and nonclinical factors on tracheostomy practice.

DESIGN

Analysis of Project Impact, a multi-institutional critical care administrative database.

SETTING

Medical school.

PATIENTS

Data from 43,916 patients were reviewed.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Tracheostomy was performed in 2,473 (5.6%) of 43,916 patients analyzed. Tracheostomy patients had a higher survival rate than nontracheostomy patients (78.1 vs. 71.7%, p < .001) and underwent this procedure following a median (25th-75th percentile) of 9.0 (5.0-14.0) days of ventilatory support. Tracheostomy frequency and timing varied significantly comparing patient, intensive care unit, and hospital characteristics (p < .05 for all). Tracheostomy timing correlated significantly with duration of mechanical ventilation (r = .690), intensive care unit (r = .610), and hospital length of stay (r = .341, p < .001 for all). At most, 22% of patients were supported via tracheostomy at any given time. Although a minority, tracheostomy patients accounted for 26.2%, 21.0%, and 13.5% of all ventilator, intensive care unit, and hospital days, respectively.

CONCLUSIONS

Although practice varies substantially, tracheostomy timing appears significantly associated with duration of mechanical ventilation, intensive care unit length of stay, and hospital length of stay. These findings emphasize the need for an adequately supported multiple-center trial to better define patient selection for tracheostomy and to test the hypothesis that timing of this procedure influences clinically important outcomes.

Evaluation of the Applicability, Efficacy, and Safety of a Thromboembolic Event Prophylaxis Guideline Designed for Quality Improvement of the Traumatically Injured Patient

BACKGROUND

Thromboembolic events (TE) such as deep venous thrombosis (DVT) and pulmonary embolism (PE) are common after trauma. Our Trauma Practice Management Committee developed an evidence-based DVT/PE prophylaxis guideline using a modified Delphi approach to standardize care and reduce TE rates. Our objective was to evaluate the applicability, efficacy, and safety of this guideline in the traumatized patient, especially those admitted first to the intensive care unit (ICU).

METHODS

We developed a risk-stratified DVT/PE prophylaxis guideline incorporating specific injuries, pertinent history, and physiologic parameters, favoring aggressive therapy in those at highest risk of dying from a PE. We prospectively collected data using this guideline in all patients admitted to the trauma or orthopedic-trauma services that were expected to stay for more than 48 hours (March-December 2003). Comparison was made with historical controls. Data collected included DVT, PE, prophylaxis level chosen, inferior vena cava filters, admission service and location, TRISS scores, length of stay, outcomes, adverse events, and specific risk factors.

RESULTS

TE rates after implementation of the guideline were lower than historical controls for all patients (1.9% vs. 1.0%, p = 0.059) and for patients admitted first to the ICU (6.3% vs. 2%, p = 0.018). Completed sheets were collected for 46% of the targeted population. No bleeding events caused by guideline anticoagulation were noted, and one death occurred after inferior vena cava filter placement. Nine of the 12 TEs in the treatment group were in patients with spine or closed-head injury, delaying chemical prophylaxis.

CONCLUSION

Form-based, risk-adjusted prophylaxis against TE leads to lower TE rates in a general and orthopedic ICU trauma population. Protocol compliance should be enforced.

A meta-analysis of controlled trials of anticoagulant therapies in patients with sepsis

Although coagulation abnormalities may partly underlie the physiologic derangements of the sepsis syndrome, anticoagulant therapies have produced mixed results on survival in clinical studies. We hypothesized that a meta-analysis of clinical trials of anticoagulants in sepsis may provide insight as to the therapeutic utility of targeting the clotting cascade in this syndrome. We searched electronic databases and reviewed bibliographies of pertinent articles to identify controlled clinical studies in which anticoagulants had been administered as adjunctive therapy to patients with sepsis. After establishing statistical homogeneity, odds ratios (OR; with 95% confidence intervals [CI]) for effect of these agents on mortality and bleeding complications were determined using Mantel-Haenszel methodology. Potential for publication bias was assessed by the use of a statistical test of funnel plot asymmetry. Weighted linear regression was performed to examine the effect of control group mortality rate on treatment efficacy. We identified 11 studies that satisfied our inclusion criteria. Collectively, these studies enrolled 4690 patients (range of 29-2314) and examined three agents: antithrombin III (2659 patients), tissue factor pathway inhibitor (210 patients), and activated protein C (1821 patients). After establishing statistical homogeneity (P > 0.10, chi-square), we found that the OR (with 95% CI) for effect on mortality for these agents, relative to control treatment, was 0.8692 (0.7519-1.006). Weighted linear regression analysis was consistent with a control group mortality dependent effect for these agents (P = 0.02). Only five of the studies reported bleeding complications. Pooling the results of these five studies (4376 patients) resulted in an OR (with 95% CI) of 1.70 (1.40-2.07) relative to control treatment for bleeding risk. Anticoagulants as adjuvant therapy do not appear to improve outcome in sepsis and are associated with a significant risk of bleeding complications. To the extent that their treatment effect is dependent upon disease severity, the safety and efficacy of these agents may be enhanced by refinement in techniques of clinical stratification.

Template-directed dye-terminator incorporation with fluorescence polarization detection for analysis of single nucleotide polymorphisms implicated in sepsis

Sepsis continues to be a common source of morbidity and mortality in critically ill patients. Single nucleotide polymorphisms (SNPs) present in genes encoding inflammatory mediators have been associated with predisposition and outcome in this syndrome. The use of high throughput SNP analysis in large epidemiological studies is necessary to more fully understand the genetic underpinnings of this disease. We adapted template-directed dye-terminator incorporation with fluorescence polarization detection (TDI-FP) to the analysis of eight SNPs implicated in mediating the sepsis syndrome: TNF-alpha (-308), TNF-alpha (-238), TNF-beta (+250), IL-1beta (+3953), IL-6 (-174), IL-10 (-592), plasminogen activator inhibitor-1 (PAI-1 (-675)), and TLR4 299 (+1032). Optimization of PCR, amplicon purification, and template-directed dye-terminator incorporation reactions were necessary to achieve acceptable performance characteristics for these assays. Sequence validated samples served as controls. Using this method we were able to assign genotype in 99.3% of assays and identified 64 unique genotypes in samples obtained from 90 individuals. TDI-FP is a flexible and robust method of SNP detection that can be optimized in a systematic fashion. This method has potential advantages compared with other high throughput genotyping techniques and appears well suited to clinical situations requiring analysis of large numbers of samples.

Ultrapermeable, reverse-selective nanocomposite membranes

Polymer nanocomposites continue to receive tremendous attention for application in areas such as microelectronics, organic batteries, optics, and catalysis. We have discovered that physical dispersion of nonporous, nanoscale, fumed silica particles in glassy amorphous poly(4-methyl-2-pentyne) simultaneously and surprisingly enhances both membrane permeability and selectivity for large organic molecules over small permanent gases. These highly unusual property enhancements, in contrast to results obtained in conventional filled polymer systems, reflect fumed silica-induced disruption of polymer chain packing and an accompanying subtle increase in the size of free volume elements through which molecular transport occurs, as discerned by positron annihilation lifetime spectroscopy. Such nanoscale hybridization represents an innovative means to tune the separation properties of glassy polymeric media through systematic manipulation of molecular packing.

The frequency and effects of cytochrome P450 (CYP) 2C9 polymorphisms in patients receiving warfarin

BACKGROUND

Warfarin sodium (warfarin) is commonly prescribed in surgical practice. Warfarin use is complicated by an unpredictable dose response that may be due in part to genetically determined differences in metabolic capacity. To better understand the interaction between genotype and response to warfarin therapy, we determined the frequency and functional effects of polymorphisms of the predominant cytochrome P450 subfamily responsible for warfarin metabolism (eg, CYP2C9) in an ethnically defined U.S. patient population.

DESIGN

Patients requiring chronic anticoagulation with warfarin sodium (warfarin) were recruited over an 11-month period (June 1999 through May 2000) from the inpatient and outpatient divisions of a tertiary care medical center in this prospective observational study. Clinical and demographic information was collected and CYP2C9 genotype was determined.

RESULTS

One hundred fifty-three patients receiving warfarin therapy for at least four weeks and comprising two ethnic groups [33 African Americans (22%) and 120 Caucasians (78%)] were genotyped. The mean weekly warfarin dose (+/-SEM) for all patients [36.9 (+/- 1.5) mg] was not influenced by gender [85 males (56%), 68 females (44%)] or ethnicity (p>0.05 for both), but was significantly affected by age (p = 0.006 for weight adjusted warfarin dose). The frequencies of CYP polymorphisms were as follows: 2C9*2 (24/153) 15.7%, 2C9*3 (23/153) 15.0%. There were no gender differences in polymorphism frequency (CYP2C9*2 frequency = (13/ 85) 15.3% in males, (12/68) 17.6% in females, p=0.74; CYP2C9*3 frequency = (15/85) 17.6% in males and (8/68) 11.8% in females, p = 0.38). CYP polymorphisms were much less common in African Americans than Caucasians [(5/33) 15.2% versus (47/120) 39.2%, respectively p = 0.05)]. Patients with CYP polymorphisms (2C9*2, 2C9*3) had significantly lower warfarin doses compared to patients with wild-type genotypes [30.6 (+/- 2.5) mg versus 40.1 (+/- 1.7) mg, p = 0.0021] . Stepwise backward regression analysis suggested a moderate ability to predict warfarin dose based on CYP genotype (r2 = 0.26), p < 0.01).

CONCLUSIONS

CYP2C9 polymorphisms are common, associated with significant reductions in warfarin dose, and partly account for interpatient variability in warfarin sensitivity. As interactions between genetic factors and other variables that influence warfarin effect are more completely understood, CYP analysis may prove a useful adjunct for increasing the safety and efficacy of this agent.

Coagulation inhibitors in the treatment of sepsis

Despite advances in supportive care, sepsis and septic shock continue to be major causes of morbidity and mortality in critically ill patients. The lack of efficacy of anti-inflammatory drugs in patients with sepsis has shifted interest toward developing alternative treatments. The observation that clotting system activation may in part underlie the physiological derangements of sepsis has resulted in efforts to target the clotting cascade as a therapeutic strategy. Anticoagulants have been shown to ameliorate physiological derangements and improve survival in animal sepsis models. Three agents have undergone extensive study in humans: recombinant human activated protein C (rhAPC, drotrecogin-alpha), antithrombin III (ATIII) and tissue factor pathway inhibitor (TFPI). While a recent Phase III study of rhAPC suggests a survival benefit in patients with sepsis, major concerns about this trial include the manner in which the study was conducted, the potential toxicity of rhAPC and the questionable efficacy of this agent in patients with low mortality risk. Further clinical testing of rhAPC appears to be necessary to better define the target population most appropriate for its use. In contrast, a large Phase III study of high dose ATIII in patients with sepsis failed to show a treatment benefit with this agent. Finally, while TFPI has undergone extensive preclinical and Phase II testing, the results of Phase III studies have not been published. In summary, while coagulation inhibitors may ultimately have a therapeutic role in selected subgroups of patients with sepsis, the efficacy and safety of this class of agents remain to be proven.

Sepsis-induced apoptosis causes progressive profound depletion of B and CD4+ T lymphocytes in humans

Patients with sepsis have impaired host defenses that contribute to the lethality of the disorder. Recent work implicates lymphocyte apoptosis as a potential factor in the immunosuppression of sepsis. If lymphocyte apoptosis is an important mechanism, specific subsets of lymphocytes may be more vulnerable. A prospective study of lymphocyte cell typing and apoptosis was conducted in spleens from 27 patients with sepsis and 25 patients with trauma. Spleens from 16 critically ill nonseptic (3 prospective and 13 retrospective) patients were also evaluated. Immunohistochemical staining showed a caspase-9-mediated profound progressive loss of B and CD4 T helper cells in sepsis. Interestingly, sepsis did not decrease CD8 T or NK cells. Although there was no overall effect on lymphocytes from critically ill nonseptic patients (considered as a group), certain individual patients did exhibit significant loss of B and CD4 T cells. The loss of B and CD4 T cells in sepsis is especially significant because it occurs during life-threatening infection, a state in which massive lymphocyte clonal expansion should exist. Mitochondria-dependent lymphocyte apoptosis may contribute to the immunosuppression in sepsis by decreasing the number of immune effector cells. Similar loss of lymphocytes may be occurring in critically ill patients with other disorders.

Extreme warfarin sensitivity in siblings associated with multiple cytochrome P450 polymorphisms

Warfarin use is complicated by an erratic dose response. Warfarin is metabolized by two distinct subfamilies of the cytochrome P450 (CYP) complex. We describe two siblings with extreme sensitivity to warfarin who share an unusual CYP genotype. These individuals illustrate both the importance of genetics in influencing the metabolism of warfarin as well as the potential utility of genetic testing as a guide to prescribing this medication.

A prospective, randomized study comparing percutaneous with surgical tracheostomy in critically ill patients

OBJECTIVE

To determine the relative cost-effectiveness of percutaneous dilational tracheostomy (PDT) and surgical tracheostomy (ST) in critically ill patients.

DESIGN

Prospective randomized study.

SETTING

Medical, surgical, and coronary intensive care units at Barnes-Jewish Hospital, a tertiary care medical center.

PATIENTS

Eighty critically ill mechanically ventilated patients requiring elective tracheostomy.

INTERVENTIONS

Randomization to either PDT performed in the intensive care unit or ST performed in the operating room.

MEASUREMENTS AND MAIN RESULTS

Treatment groups were well matched with respect to age (PDT, 65.44 +/- 2.82 [mean +/- se] years; ST, 61.4 +/- 2.89 years, p = Ns), gender (PDT, 45% males; ST, 47.5% males, p = NS), severity of illness (Acute Physiology and Chronic Health Evaluation II score: PDT, 16.87 +/- 0.84; ST, 17.88 +/- 0.92, p = NS), and principle diagnosis. PDT was performed more quickly (PDT, 20.1 +/- 2.0 mins; ST, 41.7 +/- 3.9 mins, p < .0001) and was associated with lower patient charges than ST (total patient charges: PDT, 1,569 dollars +/- 157 dollars vs. ST, 3,172 dollars +/- 114 dollars; equipment/supply charges: PDT, 688 dollars +/- 103 dollars vs. ST, 1,526 dollars +/- 87 dollars; professional charges: PDT, 880 dollars +/- 54 dollars vs. ST, 1,647 dollars +/- 50 dollars; p < .0001 for all). There were no differences in days intubated before tracheostomy (PDT, 12.7 +/- 1.1 days; ST, 15.6 +/- 1.9, p = .20), intensive care unit length of stay (PDT, 24.5 +/- 2.5 days; ST, 28.5 +/- 3.1 days, p = .33), or hospital length of stay (PDT 49.7 +/- 4.2 days; ST, 43.7 +/- 3.5 days, p = .28) when we compared these two techniques.

CONCLUSIONS

PDT is a cost-effective alternative to ST. The reduction in patient charges associated with PDT in this study resulted from the procedure being performed in the intensive care unit, thus eliminating the need for operating room facilities and personnel. PDT may become the procedure of choice for electively establishing tracheostomy in the appropriately selected patient who requires long-term mechanical ventilation.

Interleukin-1 receptor antagonist as therapy for inflammatory disorders

IL-1 is a pivotal mediator of the immune response and has been implicated in inflammatory and infectious diseases. As a consequence, the administration of IL-1 receptor antagonist (IL-1ra), a recombinantly synthesised endogenous inhibitor of IL-1, has appeal as a therapeutic strategy in these conditions. To date, the largest clinical experiences with IL-1ra have been in the setting of sepsis and rheumatoid arthritis (RA). Like other anti-inflammatory agents that target a specific mediator, IL-1ra was found to lack efficacy when given in conjunction with standard therapy in patients with sepsis and septic shock. In contrast, recent studies enrolling patients with RA suggest that IL-1ra significantly ameliorates disease activity and retards joint destruction. Whether the respective lack of efficacy and success of IL-1ra in these two diseases is a result of differences in the pathologic processes involved, or reflects the nature in which the clinical studies were conducted, is unclear. Further, the effectiveness of IL-1ra compared to other anticytokine and conventional treatments in RA remains to be clarified. Nonetheless, the recent finding that IL-1ra has the ability to favourably influence a chronic inflammatory disease supports the hypothesis that inhibition of a single mediator of the immune response may have clinical impact.

A meta-analysis of prospective trials comparing percutaneous and surgical tracheostomy in critically ill patients

STUDY OBJECTIVES

Tracheostomy is one of the most commonly performed procedures in the patient receiving long-term mechanical ventilation. While percutaneous dilational tracheostomy (PDT) is becoming increasingly utilized as an alternative to conventional surgical tracheostomy, most literature evaluating these two techniques is neither prospective nor controlled. We performed a meta-analysis of available prospective controlled studies comparing PDT and surgical tracheostomy in critically ill patients to more fully understand the relative benefits and risks of these two procedures in this population.

DESIGN

Meta-analysis using Mantel-Haenszel fixed effect model.

INTERVENTIONS

We performed searches of MEDLINE, Current Contents, Best Evidence, Cochrane, and HealthSTAR databases from 1985 to present to identify prospective controlled studies comparing PDT and surgical tracheostomy in critically ill patients. After establishing clinical and statistical homogeneity (Q: statistic), studies were analyzed by a Mantel-Haenszel fixed effect model. For each clinical end point examined, PDT and surgical tracheostomy were compared by calculating either absolute differences or odds ratios (ORs) with 95% confidence intervals (CIs) for continuous or discrete variables, respectively.

MEASUREMENTS AND RESULTS

We pooled data from five studies (236 patients) satisfying our search criteria to analyze eight clinical end points. Operative time was shorter for PDT than surgical tracheostomy: absolute difference with 95% CI, 9. 84 min (7.83 to 10.85 min). There was no difference comparing PDT and surgical tracheostomy with respect to overall operative complication rates: OR with 95% CI, 0.732 (0.05 to 9.37). However, relative to surgical tracheostomy, PDT was associated with less perioperative bleeding (OR with 95% CI, 0.14 [0.02 to 0.39]), a lower overall postoperative complication rate (OR with 95% CI, 0.14 [0.07 to 0.29]), as well as a lower postoperative incidence of bleeding (OR with 95% CI, 0.39 [0.17 to 0.88]), and stomal infection (OR with 95% CI, 0.02 [0.01 to 0.07]). No difference was identified in days intubated prior to tracheostomy (absolute difference with 95% CI, 0.16 days [- 0.9 to 1.22 days]), overall procedure-related complications (OR with 95% CI, 0.73 [0.06 to 9.37]), or death (OR with 95% CI, 0.63 [0.18 to 2.20]) comparing these two techniques.

CONCLUSIONS

Despite its popularity, there are currently only a limited number of small studies prospectively evaluating PDT and surgical tracheostomy. Our meta-analysis of these studies suggests potential advantages of PDT relative to surgical tracheostomy, including ease of performance, and lower incidence of peristomal bleeding and postoperative infection. If confirmed by additional, adequately powered prospective trials, these findings support PDT as the procedure of choice for the establishment of elective tracheostomy in the appropriately selected critically ill patient.

Rapid onset of intestinal epithelial and lymphocyte apoptotic cell death in patients with trauma and shock

OBJECTIVE

Apoptosis is a cellular suicide program that can be activated by cell injury or stress. Although a number of laboratory studies have shown that ischemia/reperfusion injury can induce apoptosis, few clinical studies have been performed. The purpose of this study was to determine whether apoptosis is a major mechanism of cell death in intestinal epithelial cells and lymphocytes in patients who sustained trauma, shock, and ischemia/ reperfusion injury.

DESIGN

Intestinal tissues were obtained intraoperatively from 10 patients with acute traumatic injuries as a result of motor vehicle collisions or gun shot wounds. A control population consisted of six patients who underwent elective bowel resections. Apoptosis was evaluated by conventional light microscopy, laser scanning confocal microscopy using the nuclear staining dye Hoechst 33342, immunohistochemical staining for active caspase-3, and immunohistochemical staining for cytokeratin 18.

SETTING

Academic medical center.

PATIENTS

Patients with trauma or elective bowel resections.

MEASUREMENTS AND MAIN RESULTS

Extensive focal crypt epithelial and lymphocyte apoptosis were demonstrated by multiple methods of examination in the majority of trauma patients. Trauma patients having the highest injury severity score tended to have the most severe apoptosis. Repeat intestinal samples obtained from two of the trauma patients who had a high degree of apoptosis on initial evaluation were negative for apoptosis at the time of the second operation. Tissue lymphocyte apoptosis was associated with a markedly decreased circulating lymphocyte count in 9 of 10 trauma patients.

CONCLUSIONS

Focal apoptosis of intestinal epithelial and lymphoid tissues occurs extremely rapidly after injury. Apoptotic loss of intestinal epithelial cells may compromise bowel wall integrity and be a mechanism for bacterial or endotoxin translocation into the systemic circulation. Apoptosis of lymphocytes may impair immunologic defenses and predispose to infection.