Contactless skin perfusion monitoring with video cameras: tracking pharmacological vasoconstriction and vasodilation using photoplethysmographic changes

Objectives.Clinical assessment of skin perfusion informs prognosis in critically ill patients. Video camera monitoring could provide an objective, continuous method to monitor skin perfusion. In this prospective, interventional study of healthy volunteers, we tested whether video camera-derived photoplethysmography imaging and colour measurements could detect drug-induced skin perfusion changes.Approach.We monitored the lower limbs of 30 volunteers using video cameras while administering phenylephrine (a vasoconstrictor) and glyceryl trinitrate (a vasodilator). We report relative pixel intensity changes from baseline, as absolute values are sensitive to environmental factors. The primary outcome was the pre- to peak- infusion green channel amplitude change in the pulsatile PPGi waveform component. Secondary outcomes were pre-to-peak changes in the photoplethysmographic imaging waveform baseline, skin colour hue and skin colour saturation.Main results.The 30 participants had a median age of 29 years (IQR 25-34), sixteen (53%) were male. A 34.7% (p= 0.0001) mean decrease in the amplitude of the pulsatile photoplethysmographic imaging waveform occurred following phenylephrine infusion. A 30.7% (p= 0.000004) mean increase occurred following glyceryl trinitrate infusion. The photoplethysmographic imaging baseline decreased with phenylephrine by 2.1% (p= 0.000 02) and increased with glyceryl trinitrate by 0.5% (p= 0.026). Skin colour hue changed in opposite direction with phenylephrine (-0.0013,p= 0.0002) and glyceryl trinitrate (+0.0006,p= 0.019). Skin colour saturation decreased with phenylephrine by 0.0022 (p= 0.0002), with no significant change observed with glyceryl trinitrate (+0.0005,p= 0.21).Significance.Drug-induced vasoconstriction and vasodilation are associated with detectable changes in photoplethysmographic imaging waveform parameters and skin hue. Our findings suggest video cameras have great potential for continuous, contactless skin perfusion monitoring.

Effects of physical activity and feed and water restriction at reimplanting time on feed intake patterns, growth performance, and carcass characteristics of finishing beef steers

In the feedlot, there can be a decrease in dry matter intake (DMI) associated with reimplanting cattle that negatively affects growth performance. This study was conducted to determine the mechanisms causing a decrease in DMI after reimplanting and identify a strategy to mitigate the decrease. Crossbred steers (n = 200; 10 pens/treatment; initial bodyweight [BW] = 386 ± 4.9 kg) were used in a randomized complete block design experiment. Cattle were implanted with Revalor-IS on day 0. Treatments included a Revalor-200 implant on day 90 before feeding with the following management practices imposed: 1) steers were returned to their home pen immediately after reimplant (PCON); 2) steers were placed in pens and restricted from feed and water for 4 h (RES); 3) steers were walked an additional 805 m after reimplant and then returned home (LOC); 4) steers were restricted from feed and water for 4 h and walked an additional 805 m (RES + LOC); 5) steers were given an oral bolus of Megasphaera elsdenii (Lactipro; MS Biotec, Wamego, KS) and were restricted from feed and water for 4 h, and then walked an additional 805 m (LACT). One hundred steers were given an ear tag to record minutes of activity (ESense Flex Tags, Allflex Livestock Intelligence, Madison, WI). As a percentage of BW, DMI was 5% greater (P = 0.01) from reimplant to end for PCON vs. RES, LOC, and RES + LOC treatments. Likewise, as a percentage of BW, DMI was 6.6% greater (P = 0.03) from reimplant to end and 4.0% greater (P = 0.05) overall for the PCON treatment vs. the LOC treatment. Overall, DMI as a percentage of BW was 3.3% greater (P = 0.02) for PCON vs. RES, LOC, and RES + LOC treatments. There was an increase in G:F from reimplant to end (P = 0.05) for RES + LOC vs. the LACT treatment. From these data, we conclude that restricting cattle from feed and water for 4 h after reimplanting did not alter subsequent DMI. Increasing locomotion had the greatest negative effect on DMI and growth performance. Management strategies to decrease locomotion associated with reimplanting would be beneficial to DMI and overall growth performance of finishing beef steers.

Advancing Digital Health Equity: A Policy Paper of the Infectious Diseases Society of America and the HIV Medicine Association

The SARS-CoV-2 virus pandemic has revolutionized the practice of ambulatory medicine, triggering rapid dissemination of digital healthcare modalities, including synchronous video visits. However, social determinants of health, such as age, race, income, and others, predict readiness for telemedicine and individuals who are not able to connect virtually may become lost to care. This is particularly relevant to the practice of Infectious Diseases (ID) and HIV Medicine, as we care for high proportions of individuals whose health outcomes are affected by such factors. Furthermore, delivering high-quality clinical care in ID and HIV practice necessitates discussion of sensitive topics, which is challenging over video without proper preparation. We describe the “digital divide,” emphasize the relevance to ID and HIV practice, underscore the need to study the issue and develop interventions to mitigate its impact, and provide suggestions for optimizing telemedicine in ID and HIV clinics.

Advancing Digital Health Equity: A Policy Paper of the Infectious Diseases Society of America and the HIV Medicine Association

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has revolutionized the practice of ambulatory medicine, triggering rapid dissemination of digital healthcare modalities, including synchronous video visits. However, social determinants of health, such as age, race, income, and others, predict readiness for telemedicine and individuals who are not able to connect virtually may become lost to care. This is particularly relevant to the practice of infectious diseases (ID) and human immunodeficiency virus (HIV) medicine, as we care for high proportions of individuals whose health outcomes are affected by such factors. Furthermore, delivering high-quality clinical care in ID and HIV practice necessitates discussion of sensitive topics, which is challenging over video without proper preparation. We describe the “digital divide,” emphasize the relevance to ID and HIV practice, underscore the need to study the issue and develop interventions to mitigate its impact, and provide suggestions for optimizing telemedicine in ID and HIV clinics.

Impact of Abstinence and of Reducing Illicit Drug Use Without Abstinence on Human Immunodeficiency Virus Viral Load

BACKGROUND

Substance use is common among people living with human immunodeficiency virus (PLWH) and a barrier to achieving viral suppression. Among PLWH who report illicit drug use, we evaluated associations between HIV viral load (VL) and reduced use of illicit opioids, methamphetamine/crystal, cocaine/crack, and marijuana, regardless of whether or not abstinence was achieved.

METHODS

This was a longitudinal cohort study of PLWH from 7 HIV clinics or 4 clinical studies. We used joint longitudinal and survival models to examine the impact of decreasing drug use and of abstinence for each drug on viral suppression. We repeated analyses using linear mixed models to examine associations between change in frequency of drug use and VL.

RESULTS

The number of PLWH who were using each drug at baseline ranged from n = 568 (illicit opioids) to n = 4272 (marijuana). Abstinence was associated with higher odds of viral suppression (odds ratio [OR], 1.4-2.2) and lower relative VL (ranging from 21% to 42% by drug) for all 4 drug categories. Reducing frequency of illicit opioid or methamphetamine/crystal use without abstinence was associated with VL suppression (OR, 2.2, 1.6, respectively). Reducing frequency of illicit opioid or methamphetamine/crystal use without abstinence was associated with lower relative VL (47%, 38%, respectively).

CONCLUSIONS

Abstinence was associated with viral suppression. In addition, reducing use of illicit opioids or methamphetamine/crystal, even without abstinence, was also associated with viral suppression. Our findings highlight the impact of reducing substance use, even when abstinence is not achieved, and the potential benefits of medications, behavioral interventions, and harm-reduction interventions.

Infectious Diseases Society of America Position Statement on Telehealth and Telemedicine as Applied to the Practice of Infectious Diseases

Over the last 2 decades, telemedicine has effectively demonstrated its ability to increase access to care. This access has the ability to deliver quality clinical care and offer potential savings to the healthcare system. With increasing frequency, physicians, clinics, and medical centers are harnessing modern telecommunications technologies to manage a multitude of acute and chronic conditions, as well as incorporating telehealth into teaching and research. The technologies spanning telehealth, telemedicine, and mobile health (mHealth) are rapidly evolving, and the Infectious Diseases Society of America (IDSA) has prepared this updated position statement to educate its membership on the use of telemedicine and telehealth technologies. IDSA supports the appropriate and evidence-based use of telehealth technologies to provide up-to-date, timely, cost-effective subspecialty care to resource-limited populations.

Development of gynecomastia following initiation of bictegravir/emtricitabine/tenofovir alafenamide

Bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF) is a recently approved single-tablet antiretroviral regimen and is recommended as a first-line agent. No cases of gynecomastia were reported in clinical trials. We report development of ultrasound-confirmed gynecomastia in a previously antiretroviral-naïve patient approximately two months after starting BIC/FTC/TAF, which resolved ten weeks after discontinuing bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF) based therapy.

Real-world evaluation of the safety and tolerability of abacavir/dolutegravir/lamivudine in an incarcerated population

A trend of increased adverse effects and laboratory abnormalities was observed in patients treated at the University of Illinois Hospital and Health Sciences System (UIH) HIV Telemedicine Clinic after switching to abacavir/dolutegravir/lamivudine (ABC/DTG/3TC). Therefore, we sought to investigate if major clinical trials overestimated the safety and tolerability of DTG-based antiretroviral therapy (ART). This study was a single-center, retrospective, pre- and post-analysis of incarcerated patients receiving care at the UIH HIV Telemedicine Clinic, USA. Patients included were adults with HIV switched from previous ART to ABC/DTG/3TC. Primary endpoints included patient-reported adverse effects and changes in renal and hepatic function from baseline. A total of 95 patients were included in the study. After switching from previous ART to ABC/DTG/3TC, 20% of patients reported incidence of adverse effects. Most common were headache (7.4%), nausea (6.3%) rash (3.2%), fatigue (3.2%), and insomnia (2.1%). There were statistically significant increases in serum creatinine (SCr), in 20% of the patients (P < 0.0001), with a median increase of 0.38 mg/dl. ABC/DTG/3TC appears to have similar or fewer adverse effects in the real-world incarcerated population compared to clinical trials. DTG-based ART can cause statistically significant increases in SCr in some patients.

Immunologic and Virologic Outcomes of Obese and Nonobese Incarcerated Adults on Antiretroviral Therapy for HIV Infection

Background:

Obesity is common among patients with HIV. The objective of this study was to characterize response to antiretroviral therapy (ART) in a cohort of obese incarcerated adults compared to a nonobese cohort.

Methods:

A retrospective matched cohort study was conducted in an HIV telemedicine clinic. Patients with body mass index (BMI) >30 kg/m² who received the same ART with >95% adherence for at least 6 months were matched to nonobese patients by age, gender, ART, CD4 count, and viral load at baseline.

Results:

Twenty pairs were included, with an average BMI of 24 kg/m² in the nonobese cohort and 35 kg/m² in the obese cohort. No difference was observed in the proportion of patients who achieved virologic suppression or the change in CD4 count from baseline to 6 to 12 months.

Conclusion:

This study revealed no differences in immunologic recovery or virologic suppression between obese and nonobese patients in an adult correctional population.

Availability and performance of image-based, non-contact methods of monitoring heart rate, blood pressure, respiratory rate, and oxygen saturation: a systematic review

OBJECTIVE

Over the last 15 years, developments in camera technology have coincided with increased availability and affordability. This has led to an increasing interest in using these technologies in healthcare settings. Image-based monitoring methods potentially allow multiple vital signs to be measured concurrently using a non-contact sensor. We have undertaken a systematic review of the current availability and performance of these monitoring methods.

APPROACH

A multiple database search was conducted using MEDLINE, Embase, CINAHL, Cochrane Library, OpenGrey, IEEE Xplore Library and ACM Digital Library to July 2018. We included studies comparing image-based heart rate, respiratory rate, oxygen saturation and blood pressure monitoring methods against one or more validated reference device(s). Each included study was assessed using the modified GRRAS criteria for reporting bias.

MAIN RESULTS

Of 30 279 identified studies, 161 were included in the final analysis. Twenty studies (20/161, 12%) were carried out on patients in clinical settings, while the remainder were conducted in academic settings using healthy volunteer populations. The 18-40 age group was best represented across the identified studies. One hundred and twenty studies (120/161, 75%) estimated heart rate, followed by 62 studies (62/161, 39%) estimating respiratory rate. Fewer studies focused on oxygen saturation (11/161, 7%) or blood pressure (6/161, 4%) estimation. Fifty-one heart rate studies (51/120, 43%) and 24 respiratory rate studies (24/62, 39%) used Bland-Altman analysis to report their results. Of the heart rate studies, 28 studies (28/51, 55%) showed agreement within industry standards of [Formula: see text]5 beats per minute. Only two studies achieved this within clinical settings. Of the respiratory rate studies, 13 studies (13/24, 54%) showed agreement within industry standards of [Formula: see text]3 breaths per minute, but only one study achieved this in a clinical setting. Statistical analysis was heterogeneous across studies with frequent inappropriate use of correlation. The majority of studies (99/161, 61%) monitored subjects for under 5 min. Three studies (3/161, 2%) monitored subjects for over 60 min, all of which were conducted in hospital settings.

SIGNIFICANCE

Heart rate and respiratory rate monitoring using video images is currently possible and performs within clinically acceptable limits under experimental conditions. Camera-derived estimates were less accurate in the proportion of studies conducted in clinical settings. We would encourage thorough reporting of the population studied, details of clinically relevant aspects of methodology, and the use of appropriate statistical methods in future studies. Systematic review registration: PROSPERO CRD42016029167 Protocol: https://systematicreviewsjournal.biomedcentral.com/articles/10.1186/s13643-017-0615-3.

Mapping sources of noise in an intensive care unit

Excessive noise in hospitals adversely affects patients' sleep and recovery, causes stress and fatigue in staff and hampers communication. The World Health Organization suggests sound levels should be limited to 35 decibels. This is probably unachievable in intensive care units, but some reduction from current levels should be possible. A preliminary step would be to identify principal sources of noise. As part of a larger project investigating techniques to reduce environmental noise, we installed a microphone array system in one with four beds in an adult general intensive care unit. This continuously measured locations and sound pressure levels of noise sources. This report summarises results recorded over one year. Data were collected between 7 April 2017 and 16 April 2018 inclusive. Data for a whole day were available for 248 days. The sound location system revealed that the majority of loud sounds originated from extremely limited areas, very close to patients' ears. This proximity maximises the adverse effects of high environmental noise levels for patients. Some of this was likely to be appropriate communication between the patient, their caring staff and visitors. However, a significant proportion of loud sounds may originate from equipment alarms which are sited at the bedside. A redesign of the intensive care unit environment to move alarm sounds away from the bed-side might significantly reduce the environmental noise burden to patients.

Risk of neurosyphilis in HIV-infected persons with syphilis lacking signs or symptoms of central nervous system infection

OBJECTIVES

People living with HIV (PLWH) are at increased risk of asymptomatic neurosyphilis; thus, it has been common practice to perform a lumbar puncture (LP) in all PLWH presenting with syphilis regardless of stage, signs or symptoms. However, this practice varies widely among clinicians. Our objective was to elucidate the number of LPs required to diagnose a single case of asymptomatic neurosyphilis.

METHODS

We performed an electronic health record (EHR) review of PLWH who were diagnosed with syphilis of any stage over a 10-year period. EHRs were reviewed to determine the number of subjects who had an LP performed, what proportion had neurological signs or symptoms, and whether a diagnosis of neurosyphilis was made at presentation or follow-up.

RESULTS

In 261 separate episodes of syphilis in 230 subjects, we found the major risk factors for asymptomatic neurosyphilis to be low CD4 T-cell count (P = 0.0007), high rapid plasma reagin (RPR) titre (P = 0.019) and lack of HIV virological suppression (P = 0.003). The majority of our subjects (78%) with neurosyphilis presented with central nervous system (CNS) symptoms. We estimate, if standard practice is to perform LP in all patients, that the number needed to test (NNTT) = 38.

CONCLUSIONS

This large number of potentially unnecessary LPs, along with heterogeneity of presentation, and the never-nil risk of asymptomatic neurosyphilis should be incorporated into clinical decision-making. The majority of PLWH presenting with a serological diagnosis of syphilis, but no neurological signs or symptoms, do not necessarily require an LP for an evaluation of asymptomatic neurosyphilis.

Changes in health-related quality of life after discharge from an intensive care unit: a systematic review

Quality of life after critical illness is becoming increasingly important as survival improves. Various measures have been used to study the quality of life of patients discharged from intensive care. We systematically reviewed validated measures of quality of life and their results. We searched PubMed, CENTRAL, CINAHL, Web of Science and Open Grey for studies of quality of life, measured after discharge from intensive care. We categorised studied populations as: general; restricted to level‐3 care or critical care beyond 5 days; and septic patients. We included quality of life measured at any time after hospital discharge. We identified 48 studies. Thirty‐one studies used the Medical Outcomes Study 36‐Item Short Form Health Survey (SF‐36) and 19 used the EuroQol‐5D (EQ‐5D); eight used both and nine used alternative validated measures. Follow‐up rates ranged from 26–100%. Quality of life after critical care was worse than for age‐ and sex‐matched populations. Quality of life improved for one year after hospital discharge. The aspects of life that improved most were physical function, physical role, vitality and social function. However, these domains were also the least likely to recover to population norms as they were more profoundly affected by critical illness.

Towards elucidating the photochemistry of the sunscreen filter ethyl ferulate using time-resolved gas-phase spectroscopy

Ultrafast time-resolved ion yield (TR-IY) and velocity map imaging spectroscopies are employed to reveal the relaxation dynamics after photoexcitation in ethyl 4-hydroxy-3-methoxycinnamate (ethyl ferulate, EF), an active ingredient in commercially available sunscreens. In keeping with a bottom-up strategy, the building blocks of EF, 2-methoxy-4-vinylphenol (MVP) and 4-hydroxy-3-methoxycinnamyl alcohol (coniferyl alcohol, ConA), were also studied to assist in our understanding of the dynamics of EF as we build up in molecular complexity. In contrast to the excited state dynamics of MVP and ConA, which are described by a single time constant (>900 ps), the dynamics of EF are described by three time constants (15 ± 4 ps, 148 ± 47 ps, and >900 ps). A mechanism is proposed involving internal conversion (IC) between the initially excited S₁(1¹ππ*) and S₂(1¹nπ*) states followed by intramolecular vibrational redistribution (IVR) on both states, in competition with intersystem crossing onto neighbouring triplet states (15 ± 4 ps). IVR and IC within the triplet manifold then ensues (148 ± 47 ps) to populate a low-lying triplet state (>900 ps). Importantly, the fluorescence spectrum of EF at the S₁ origin, along with the associated lifetime (6.9 ± 0.1 ns), suggests that population is trapped, during initial IVR, on the S₁(1¹ππ*) state. This serves to demonstrate the complex, competing dynamics in this sunscreen filter molecule.

Lessons Learned From the Implementation of Seek, Test, Treat, Retain Interventions Using Mobile Phones and Text Messaging to Improve Engagement in HIV Care for Vulnerable Populations in the United States

In the United States, little is known about interventions that rely on mobile phones and/or text messaging to improve engagement in HIV care for vulnerable populations. Domestic studies using these technologies as part of the National Institute on Drug Abuse "Seek, Test, Treat, Retain" research initiative were queried regarding intervention components, implementation issues, participant characteristics, and descriptive statistics of mobile phone service delivery. Across five studies with 1,135 predominantly male, minority participants, implementation challenges occurred in three categories: (1) service interruptions; (2) billing/overage issues, and; (3) the participant user experience. Response rules for automated text messages frequently frustrated participants. The inability to reload minutes/texting capacity remotely was a significant barrier to intervention delivery. No study encountered confidentiality breaches. Service interruption was common, even if studies provided mobile phones and plans. Future studies should attend to the type of mobile phone and service, the participant user experience, and human subjects concerns.

Gender Differences in HIV Risk Behaviors Among Persons Involved in the U.S. Criminal Justice System and Living with HIV or at Risk for HIV: A "Seek, Test, Treat, and Retain" Harmonization Consortium

The U.S. female criminal justice (CJ) population is rapidly growing, yet large-scale studies exploring gender-specific HIV risk behaviors in the CJ population are lacking. This analysis uses baseline data on adults with a CJ history from eight U.S. studies in an NIH-funded "Seek, Test, Treat, Retain" harmonization consortium. Data were collected using a standardized HIV risk behavior assessment tool and pooled across studies to describe participants' characteristics and risk behaviors. Multilevel mixed-effects logistic regression models were used to test for gender-based behavior differences. Among 784 HIV-positive (21.4% female) and 5521 HIV-negative (8.5% female) participants, HIV-positive women had higher odds than HIV-positive men of engaging in condomless sexual intercourse (AOR 1.84 [1.16-2.95]) with potentially sero-discordant partners (AOR 2.40 [1.41-4.09]) and of sharing injection equipment (AOR 3.36 [1.31-8.63]). HIV risk reduction interventions targeting CJ-involved women with HIV are urgently needed as this population may represent an under-recognized potential source of HIV transmission.

Prevalence of HIV-1 transmitted drug resistance in the incarcerated population

OBJECTIVES

The aim of the study was to determine the prevalence of transmitted drug resistance (TDR)-associated mutations among treatment-naïve, incarcerated individuals with HIV-1 infection in the USA as well as the class TDR and antiretroviral (ARV) mutations present at baseline.

METHODS

Patients over the age of 18 years were included in the study if they had been diagnosed with HIV infection, if their HIV infection was managed through telemedicine and if they were incarcerated in the State of Illinois Department of Corrections between 10 July 2010 and 29 April 2016. Additionally, the patients were required to have a documented genotype and be ARV-naïve. A medical chart review was conducted to assess demographic information, disease burden, and risk factors for acquiring the virus.

RESULTS

The inclusion criteria were met for 105 patients. A total of 24 patients (23%) had a clinically significant mutation associated with resistance to any drug class. The prevalence of mutations conferring clinically significant resistance was 19% for nonnucleoside reverse transcriptase inhibitors (NNRTIs), 18% for nucleoside reverse transcriptase inhibitors (NRTIs), and 4% for protease inhibitors (PIs). Five per cent of patients had dual-class TDR to both NRTI and NNRTI drug classes and 2% of patients had mutations to both NNRTI and PI drug classes. There was no significant increase in the prevalence of clinically relevant drug resistance mutations based on demographics, burden of disease, or risk factors for acquiring the virus.

CONCLUSIONS

A high prevalence of TDR was identified in the ARV-naïve incarcerated population. The results of this study indicate an increased prevalence of TDR in a largely unstudied incarcerated population, demonstrating the need for increased monitoring of resistance in HIV-infected patients world-wide.

Cohort profile: seek, test, treat and retain United States criminal justice cohort

BACKGROUND

The STTR treatment cascade provides a framework for research aimed at improving the delivery of services, care and outcomes of PLWH. The development of effective approaches to increase HIV diagnoses and engage PLWH in subsequent steps of the treatment cascade could lead to earlier and sustained ART treatment resulting in viral suppression. There is an unmet need for research applying the treatment cascade to improve outcomes for those with criminal justice involvement.

METHODS

The Seek, Test, Treat, and Retain (STTR) criminal justice (CJ) cohort combines data from 11 studies across the HIV treatment cascade that focused on persons involved in the criminal justice system, often but not exclusively for reasons related to substance use. The studies were conducted in a variety of CJ settings and collected information across 11 pre-selected domains: demographic characteristics, CJ involvement, HIV risk behaviors, HIV and/or Hepatitis C infections, laboratory measures of CD4 T-cell count (CD4) and HIV RNA viral load (VL), mental illness, health related quality of life (QoL), socioeconomic status, health care access, substance use, and social support.

RESULTS

The STTR CJ cohort includes data on 11,070 individuals with and without HIV infection who range in age from 18 to 77 years, with a median age at baseline of 37 years. The cohort reflects racial, ethnic and gender distributions in the U.S. CJ system, and 64% of participants are African-American, 12% are Hispanic and 83% are men. Cohort members reported a wide range of HIV risk behaviors including history of injection drug use and, among those who reported on pre-incarceration sexual behaviors, the prevalence of unprotected sexual intercourse ranged across studies from 4% to 79%. Across all studies, 53% percent of the STTR CJ cohort reported recent polysubstance use.

CONCLUSIONS

The STTR CJ cohort is comprised of participants from a wide range of CJ settings including jail, prison, and community supervision who report considerable diversity in their characteristics and behavioral practices. We have developed harmonized measures, where feasible, to improve the integration of these studies together to answer questions that cannot otherwise be addressed.

HIV Subspecialty Care in Correctional Facilities Using Telemedicine

In the United States, prisons and jails contain a population at high risk for HIV infection with a relatively large proportion known to be HIV positive. However, many incarcerated persons lack access to subspecialty HIV care due to barriers of geography and travel. Telemedicine clinics can remove these barriers, increasing access to expert, multidisciplinary care. With telemedicine, correctional facilities can provide up-to-date, evidence-based HIV management, which may lead to improved compliance, greater virologic suppression, improved CD4 T-cell counts, fewer adverse drug interactions, and decreased transmission in the community. While HIV care in prisons is an example of harnessing this technology, telemedicine can be used for the diagnosis and management of multiple acute and chronic diseases for underserved populations.

Probing Rotational Motion in 4-tert-Butylcatechol through H Atom Photofragmentation: Deviations from Axial Recoil

The time-resolved photofragmentation dynamics of 4-tert-butylcatechol were studied following one photon excitation to the S1 (1(1)ππ*) state with ultraviolet radiation in the range 260 ≤ λ ≤ 286 nm. The preparation of an aligned molecular ensemble via photoexcitation leads to anisotropy in the H atom photofragments. These H atoms originate from the decay of the S1 state through coupling onto the S2 ((1)πσ*) state, which is dissociative along the nonintramolecular hydrogen bonded "free" O-H bond. The degree of anisotropy of these photogenerated H atoms decreases with increasing pump-probe time delay. This is attributed to rotational dephasing of the initially aligned molecular ensemble. The measured dephasing occurs on a time scale akin to the appearance time of these H atoms, which likely places an intrinsic lower bound on the dephasing lifetime. The present work demonstrates how a careful balance between the appearance time of the H atoms, determined by the S1 lifetime, and the rotational dephasing in 4-tert-butylcatechol provides an opportune window to probe rotational motion in real time.

A systematic review and meta-analysis of early goal-directed therapy for septic shock: the ARISE, ProCESS and ProMISe Investigators

PURPOSE

To determine whether early goal-directed therapy (EGDT) reduces mortality compared with other resuscitation strategies for patients presenting to the emergency department (ED) with septic shock.

METHODS

Using a search strategy of PubMed, EmBase and CENTRAL, we selected all relevant randomised clinical trials published from January 2000 to January 2015. We translated non-English papers and contacted authors as necessary. Our primary analysis generated a pooled odds ratio (OR) from a fixed-effect model. Sensitivity analyses explored the effect of including non-ED studies, adjusting for study quality, and conducting a random-effects model. Secondary outcomes included organ support and hospital and ICU length of stay.

RESULTS

From 2395 initially eligible abstracts, five randomised clinical trials (n = 4735 patients) met all criteria and generally scored high for quality except for lack of blinding. There was no effect on the primary mortality outcome (EGDT: 23.2% [495/2134] versus control: 22.4% [582/2601]; pooled OR 1.01 [95% CI 0.88-1.16], P = 0.9, with heterogeneity [I(2) = 57%; P = 0.055]). The pooled estimate of 90-day mortality from the three recent multicentre studies (n = 4063) also showed no difference [pooled OR 0.99 (95% CI 0.86-1.15), P = 0.93] with no heterogeneity (I(2) = 0.0%; P = 0.97). EGDT increased vasopressor use (OR 1.25 [95% CI 1.10-1.41]; P < 0.001) and ICU admission [OR 2.19 (95% CI 1.82-2.65); P < 0.001]. Including six non-ED randomised trials increased heterogeneity (I(2) = 71%; P < 0.001) but did not change overall results [pooled OR 0.94 (95% CI 0.82 to 1.07); P = 0.33].

CONCLUSION

EGDT is not superior to usual care for ED patients with septic shock but is associated with increased utilisation of ICU resources.

LKB1 deficiency enhances sensitivity to energetic stress induced by erlotinib treatment in non-small-cell lung cancer (NSCLC) cells

The tumor suppressor serine/threonine kinase 11 (STK11 or LKB1) is mutated in 20-30% of patients with non-small-cell lung cancer (NSCLC). Loss of LKB1-adenosine monophosphate-activated protein kinase (AMPK) signaling confers sensitivity to metabolic inhibition or stress-induced mitochondrial insults. We tested the hypothesis that loss of LKB1 sensitizes NSCLC cells to energetic stress induced by treatment with erlotinib. LKB1-deficient cells exhibited enhanced sensitivity to erlotinib in vitro and in vivo that was associated with alterations in energy metabolism and mitochondrial dysfunction. Loss of LKB1 expression altered the cellular response to erlotinib treatment, resulting in impaired ATP homeostasis and an increase in reactive oxygen species. Furthermore, erlotinib selectively blocked mammalian target of rapamycin signaling, inhibited cell growth and activated apoptosis in LKB1-deficient cells. Erlotinib treatment also induced AMPK activation despite loss of LKB1 expression, which was partially reduced by the application of a calcium/calmodulin-dependent protein kinase kinase 2 inhibitor (STO-609) or calcium chelator (BAPTA-AM). These findings may have significant implications for the design of novel NSCLC treatments that target dysregulated metabolic and signaling pathways in LKB1-deficient tumors.

Beta-Agonist Lung injury TrIal-2 (BALTI-2): a multicentre, randomised, double-blind, placebo-controlled trial and economic evaluation of intravenous infusion of salbutamol versus placebo in patients with acute respiratory distress syndrome

BACKGROUND

Acute respiratory distress syndrome (ARDS) is a major cause of mortality in intensive care patients and lacks effective treatments. A previous randomised controlled Phase II trial suggested that an intravenous (i.v.) infusion of salbutamol may be beneficial, as it reduced extravascular lung water and plateau airway pressure. The Beta-Agonist Lung injury TrIal-2 (BALTI-2) was initiated to evaluate the effects of this intervention on mortality in patients with ARDS.

OBJECTIVES

To evaluate whether or not, in patients with ARDS, an i.v. infusion of salbutamol given at 15 μg/kg ideal body weight (IBW)/hour for up to 7 days, compared with a placebo (0.9% sodium chloride) infusion, reduces 28-day all-cause mortality and other clinical outcomes. To evaluate salbutamol's clinical effectiveness and its cost-effectiveness in subgroups of patients.

DESIGN

A multicentre, randomised, placebo-controlled trial.

SETTING

Forty-six intensive care units (ICUs) in the UK.

PARTICIPANTS

Patients were eligible if they (1) were intubated and mechanically ventilated patients in participating ICUs; (2) were within 72 hours of onset of ARDS; (3) fulfilled American-European Consensus Conference definition for ARDS {acute-onset, severe hypoxaemic respiratory failure [partial pressure of oxygen in arterial blood/fraction of inspired oxygen ≤ 26.7 kPa (200 mmHg)] and bilateral infiltrates on the chest radiograph in the absence of clinical evidence of left atrial hypertension}; and (4) were aged ≥ 16 years.

INTERVENTIONS

Intravenous infusion of salbutamol (15 μg/kg IBW/hour) or placebo (0.9% saline) for up to 7 days.

MAIN OUTCOME MEASURES

All-cause mortality 28 days after randomisation, mortality at (first) discharge from ICU, mortality at (first) discharge from hospital, number of ventilator-free days, number of organ failure-free days, mortality at 12 months post randomisation, side effects (tachycardia/new arrhythmia/lactic acidosis) sufficient to stop treatment with trial drug, health-related quality of life (European Quality of Life-5 Dimensions and Short Form questionnaire-12 items at 6 and 12 months after randomisation), length of stay in critical care unit and length of stay in hospital.

RESULTS

Forty-six ICUs recruited patients to the trial. A total of 326 patients were randomised; 162 were allocated to salbutamol and 164 to placebo. One patient in each group withdrew consent. Recruitment was stopped after the second interim analysis because of safety concerns. Salbutamol increased 28-day mortality: 55 (34%) of 161 patients died in the salbutamol group compared with 38 (23%) of 163 in the placebo group (risk ratio 1.47, 95% confidence interval 1.03 to 2.08).

CONCLUSIONS

Treatment with i.v. salbutamol early in the course of ARDS was poorly tolerated, is unlikely to be beneficial and could worsen outcomes. Further trials of β-agonists in patients with ARDS are unlikely to be conducted. Some questions remain, such as whether or not there may be benefit at a different dose or in specific populations, but any studies investigating these would require a very strong rationale.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN38366450.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Improved virologic suppression with HIV subspecialty care in a large prison system using telemedicine: an observational study with historical controls

Correctional populations have an elevated human immunodeficiency virus (HIV) prevalence, yet many individuals lack access to subspecialty care. Our study showed that HIV-infected inmates had significantly greater virologic suppression and higher CD4 T-lymphocyte counts when managed by a multidisciplinary team of subspecialists conducting clinics via telemedicine. In other studies, these outcomes have been associated with reductions on HIV-related morbidity and mortality, as well as HIV transmission.

The economic impact of anastomotic leakage after anterior resections in English NHS hospitals: are we adequately remunerating them?

AIM

Our aim was to determine the frequency and economic impact of anastomotic leakage (AL) at local and national levels in England.

METHOD

All patients who underwent AR in Oxford between 2007 and 2009 were evaluated for AL. Hospital Episode Statistics (HES) data were used to determine reoperation rates after elective AR (n = 23 388) in England between 2000 and 2008. Hospital episode remuneration costs were calculated by the local commissioning department and compared with Department of Health (DH) reference index costs.

RESULTS

The frequency of AL following anterior resection was 10.9% (31 out of 285) in Oxford. Laparotomy for leakage was performed in 5.6% of cases. The 30-day hospital mortality rate for all ARs was 2.1%, compared with 3.2% after AL. The national relaparotomy rate (within 28 days) and 30-day hospital mortality in English National Health Service (NHS) trusts following AR were 5.9% and 2.9%, respectively. Institutional remunerated tariffs (£6233 (SD ± 965)) were similar to DH reference costs (£6319 (SD ± 1830)) after uncomplicated AR. However, there was a significant (P = 0.008) discrepancy between the remunerated tariff for AL (£9605 (SD ± 6908)) and the actual cost (£17 220 (SD ± 9642)). AL resulted in an additional annual cost of approximately £1.1 million to £3.5 million when extrapolated nationally.

CONCLUSION

The estimated economic burden of anastomotic leakage following AR is approximately double that of the remunerated tariff.

Continuity of care in a cohort of HIV-infected former jail detainees

This article describes a retrospective cohort study of HIV-infected jail detainees cared for at the Cook County Jail Clinic (CCJC), Illinois, between January and June 2007. Continuity care engagement (CCE) was defined as being seen at least once within 6 months after release at the designated continuity clinics. Being highly active antiretroviral therapy (HAART) naïve during or prior to detention, no prior HIV care, and detectable viral load at initial CCJC visit were associated with continuity care nonengagement (CCNE), while being HAART naïve during detention was the only independent predictor for CCNE. Identification of at-risk detainees and interventions based on these findings should be considered to improve CCE in this population.

PPARγ isoforms differentially regulate metabolic networks to mediate mouse prostatic epithelial differentiation

Recent observations indicate prostatic diseases are comorbidities of systemic metabolic dysfunction. These discoveries revealed fundamental questions regarding the nature of prostate metabolism. We previously showed that prostate-specific ablation of PPARγ in mice resulted in tumorigenesis and active autophagy. Here, we demonstrate control of overlapping and distinct aspects of prostate epithelial metabolism by ectopic expression of individual PPARγ isoforms in PPARγ knockout prostate epithelial cells. Expression and activation of either PPARγ 1 or 2 reduced de novo lipogenesis and oxidative stress and mediated a switch from glucose to fatty acid oxidation through regulation of genes including Pdk4, Fabp4, Lpl, Acot1 and Cd36. Differential effects of PPARγ isoforms included decreased basal cell differentiation, Scd1 expression and triglyceride fatty acid desaturation and increased tumorigenicity by PPARγ1. In contrast, PPARγ2 expression significantly increased basal cell differentiation, Scd1 expression and AR expression and responsiveness. Finally, in confirmation of in vitro data, a PPARγ agonist versus high-fat diet (HFD) regimen in vivo confirmed that PPARγ agonization increased prostatic differentiation markers, whereas HFD downregulated PPARγ-regulated genes and decreased prostate differentiation. These data provide a rationale for pursuing a fundamental metabolic understanding of changes to glucose and fatty acid metabolism in benign and malignant prostatic diseases associated with systemic metabolic stress.

A national survey of the management of delirium in UK intensive care units

BACKGROUND

Delirium is an acute organ dysfunction common amongst patients treated in intensive care units. The associated morbidity and mortality are known to be substantial. Previous surveys have described which screening tools are used to diagnose delirium and which medications are used to treat delirium, but these data are not available for the United Kingdom.

AIM

This survey aimed to describe the UK management of delirium by consultant intensivists. Additionally, knowledge and attitudes towards management of delirium were sought. The results will inform future research in this area.

METHODS

A national postal survey of members of the UK Intensive Care Society was performed. A concise two page questionnaire survey was sent, with a second round of surveys sent to non-respondents after 6 weeks. The questionnaire was in tick-box format.

RESULTS

Six hundred and eighty-one replies were received from 1308 questionnaires sent, giving a response rate of 52%. Twenty-five percent of respondents routinely screen for delirium, but of these only 55% use a screening tool validated for use in intensive care. The majority (80%) of those using a validated instrument used the Confusion Assessment Method for the Intensive Care Unit. Hyperactive delirium is treated pharmacologically by 95%; hypoactive delirium is treated pharmacologically by 25%, with haloperidol the most common agent used in both. Over 80% of respondents agreed that delirium prolongs mechanical ventilation and hospital stay and requires active treatment.

CONCLUSION

This UK survey demonstrates screening for delirium is sporadic. Pharmacological treatment is usually with haloperidol in spite of the limited evidence to support this practice. Hypoactive delirium is infrequently treated pharmacologically.

Genetic variation in the purine nucleoside phosphorylase activity of sheep red cells

The purine nucleoside phosphorylase (NP) activity of sheep red cells was determined by starch gel electrophoresis and by a spectrophotometric assay technique. Some sheep had high activity (NP-high type) and some had low or zero activity (NP-low type). The enzyme deficiency is apparently confined to the red cell since other tissues from NP-low type animals had activities similar to those from NP-high type individuals. Family data indicated that NP activity is controlled by a pair of autosomal allelic genes, designated NPH and NPL. Sheep heterozygous for the NP genes had lower enzymic activities than homozygous high-type individuals. The frequency of NP types in different breeds of sheep was determined. Barbary and Mouflon sheep had activities similar to NP-high type domestic sheep; goats had high enzyme activities but their NP had a slower electrophoretic mobility than that of sheep.

Sheep twin chimaeras with admixtures of red cell amino acid and potassium transport phenotypes

A pair of sheep twins each had two populations of red cells. Population 1 was positive for antigens Aa, Ma and Mb, was low-potassium type, possessed an amino acid transport system and was lysine-negative phenotype. Population 2 was negative for antigens Aa, and Mb, was high-potassium type, lacked the amino acid transport system and was lysine-positive phenotype. Population 2 disappeared from both sheep over a period of 8 years.

Human equilibrative nucleoside transporter (ENT) family of nucleoside and nucleobase transporter proteins

1. The human (h) SLC29 family of integral membrane proteins is represented by four members, designated equilibrative nucleoside transporters (ENTs) because of the properties of the first-characterized family member, hENT1. They belong to the widely distributed eukaryotic ENT family of equilibrative and concentrative nucleoside/nucleobase transporter proteins. 2. A predicted topology of eleven transmembrane helices has been experimentally confirmed for hENT1. The best-characterized members of the family, hENT1 and hENT2, possess similar broad permeant selectivities for purine and pyrimidine nucleosides, but hENT2 also efficiently transports nucleobases. hENT3 has a similar broad permeant selectivity for nucleosides and nucleobases and appears to function in intracellular membranes, including lysosomes. 3. hENT4 is uniquely selective for adenosine, and also transports a variety of organic cations. hENT3 and hENT4 are pH sensitive, and optimally active under acidic conditions. ENTs, including those in parasitic protozoa, function in nucleoside and nucleobase uptake for salvage pathways of nucleotide synthesis and, in humans, are also responsible for the cellular uptake of nucleoside analogues used in the treatment of cancers and viral diseases. 4. By regulating the concentration of adenosine available to cell surface receptors, mammalian ENTs additionally influence physiological processes ranging from cardiovascular activity to neurotransmission.

External Validity of a Mortality Prediction Model in Patients After Open Abdominal Aortic Aneurysm Repair Using Multi-level Methodology

OBJECTIVES

Evaluation of the prognostic ability of the APACHE-AAA model in an independent group of post-operative (open) Abdominal Aortic Aneurysm (AAA) patients.

METHODS

The model was applied to predict in-hospital mortality in 541 patients (325 elective and 216 emergencies; 489 from Oxford; 52 from Lewisham). Multi-level modelling was used to adjust for both the local structure and process of care and patient case-mix. Model performance was assessed using goodness-of-fit and subgroup analyses.

RESULTS

The model's predictive ability to discriminate between dead and alive patients was very good (ROC area=0.84). The model achieved a good fit across all strata of risk (Hosmer-Lemeshow C-test (8, N=476)=7.777, p=0.456) and in all subgroups. The model was able to rank the ICUs according to their performance independently of the patient case-mix.

CONCLUSION

The APACHE-AAA model accurately predicted in-hospital mortality in a population of patients independent of the one used to develop it, confirming its validity. The multi-level methodology employed has shown that patient outcome is not only a function of the patient case-mix but instead predictive models should also adjust for the individual hospital-related factors (structure and process of care).

A comparison of the laryngeal mask airway with facemask and oropharyngeal airway for manual ventilation by critical care nurses in children

The laryngeal mask airway is included as a first line airway device during adult resuscitation by first responders. However, there is little evidence for its role in paediatric resuscitation. Using anaesthetised children as a model for paediatric cardiopulmonary arrest, we compared the ability of critical care nurses to manually ventilate the anaesthetised child via the laryngeal mask airway compared with the facemask and oropharyngeal airway. The airway devices were inserted in random order and chest expansion was measured using an ultrasound distance transducer. The critical care nurses were able to place the laryngeal mask airway and achieve successful ventilation in 82% of children compared to 70% using the facemask and oropharyngeal airway, although the difference was not statistically significant (p = 0.136). The median time to first successful breath using the laryngeal mask airway was 39 s compared to 25 s using the facemask (p < 0.001). In this group of nurses, we did not show a difference in ventilation via a laryngeal mask airway or facemask, although facemask ventilation was achieved more quickly.

Nucleoside transport and its significance for anticancer drug resistance

This article discusses the role of nucleoside transport processes in the cytotoxicity of clinically important anticancer nucleosides. This article summarizes recent advances in the molecular biology of nucleoside transport proteins, review the current state of knowledge of the transportability of therapeutically useful anticancer nucleosides, and provide an overview of the role of nucleoside transport deficiency as a mechanism of resistance to nucleoside cytotoxicity are summarized. Several strategies for utilization of nucleoside transport processes to improve the therapeutic index of anticancer therapies, including the use of nucleoside-transport inhibitors to modulate toxicity of both nucleoside and non-nucleoside antimetabolite drugs are also presented.

Comparison of Mortality Prediction Models after Open Abdominal Aortic Aneurysm Repair

OBJECTIVES

Comparison of the accuracy of prediction of contemporary mortality prediction models after open Abdominal Aortic Aneurysm (AAA) surgery.

METHODS

Post-operative data were collected from AAA patients from 2 UK Intensive Care Units (ICU). POSSUM and VBHOM based models were compared to the APACHE-AAA model which was able to adjust for the hospital-related effect on outcome. Model performance was assessed using measures of calibration, discrimination and subgroup analysis.

RESULTS

541 patients were studied. The in-hospital mortality rate for elective AAA repair (325 patients) was: 6.2% (95% confidence interval (c.i.) 3.5 to 8.8) and for emergency repair (216 patients) was: 28.7% (95% c.i. 22.5-34.9). The APACHE-based model had the best overall fit to the whole population of AAA patients, and also separately in elective and emergency patients. The V-POSSUM physiology-only (p<0.001) and VBHOM (p=0.011) models had a poor fit in elective patients. The RAAA-POSSUM physiology-only (p<0.001) and VBHOM models (p=0.010) had a poor fit in emergency patients.

CONCLUSIONS

The APACHE-AAA model with its ability to adjust for both the hospital-related "effect" as well as the patient case-mix, was a more accurate risk stratification model than other contemporary models, in the post-operative AAA patient managed in ICU.

Use of helium-oxygen mixture in adult patients presenting with exacerbations of asthma and chronic obstructive pulmonary disease: a systematic review

We examined systematically all controlled and cross-over randomised trials in patients with acute exacerbations of asthma and chronic obstructive pulmonary disease comparing Heliox against air-oxygen mixtures. Fourteen studies were identified. In asthma studies, peak expiratory flow rate (PEFR) was increased by an average of 29.6% (95% CI 16.6-42.6) by Heliox-driven nebulisers, or by 13.3 l.min(-1) (95% CI 3.71-22.81) absolute. In studies of patients with chronic obstructive pulmonary disease receiving non-invasive ventilation the arterial carbon dioxide tension (P(a)co(2)) and respiratory rate were unchanged: weighted mean difference for P(a)co(2)-0.29kPa (95% CI - 0.64-0.07) favoured Heliox, and for respiratory rate 1.6 breaths.min(-1) (95% CI - 0.93, 4.14) favoured control. Heliox minimally reduced the work of breathing in intubated patients, and reduced intrinsic positive end expiratory pressure (iPEEP). The use of Heliox to drive nebulisers in patients with acute asthma slightly improves airflow measures. We were unable to determine whether this improved recovery.

A randomised controlled trial of the effect of continuous electronic physiological monitoring on the adverse event rate in high risk medical and surgical patients

We conducted a randomised controlled trial of mandated five-channel physiological monitoring vs standard care, in acute medical and surgical wards in a single UK teaching hospital. In all, 402 high-risk medical and surgical patients were studied. The primary outcome was the proportion of patients experiencing one or more major adverse events, including urgent staff calls, changes to higher care levels, cardiac arrests or death, in 96 h following randomisation. Secondary outcomes were the proportion of patients requiring acute treatment changes, and the 30-day and hospital mortality. In the 96 h following randomisation, 113 (56%) patients in the monitored arm and 116 (58%) in the control arm (OR 0.94, 95% CI 0.63-1.40, p = 0.76) had a major event. An acute change in treatment was necessary in 107 (53%) monitored patients and 101 (50%) control patients (OR 0.55, 95% CI 0.87-1.29). Thirty-four (17%) monitored patients and 35 (17%) control patients died within 30 days. Thirteen patients in the control group received full five-channel monitoring at the request of the ward staff. We conclude that mandated electronic vital signs monitoring in high risk medical and surgical patients has no effect on adverse events or mortality.

A national survey of intensive care follow-up clinics

Intensive care follow-up clinics allow extended review of survivors of critical illness. However, the current provision of intensive care follow-up clinics in the UK is unknown. We performed a survey of intensive care follow-up clinic practice in the UK. A questionnaire was sent to 298 intensive care units in the UK to determine the number of follow-up clinics and details of current follow-up practice. Responses were received from 266 intensive care units, an 89% response rate. Eighty units (30%) ran a follow-up clinic. Only 47 (59%) of these clinics were funded. Of those intensive care units without a follow-up clinic, 158 (88%) cited 'financial constraints' as the reason. Over half of the follow-up clinics (44 clinics, 55%) were nurse-led, and the majority (56 clinics, 77%) only routinely review patients treated on the intensive care unit for 3 or 4 days or longer. Nearly half of the follow-up clinics (39 clinics, 49%) have pre-negotiated access to at least one other out-patient service.

Nitric oxide synthase is downregulated, while haem oxygenase is increased, in patients with septic shock

BACKGROUND

The vasodilatation characteristic of human septic shock is conventionally attributed to increased nitric oxide production, primarily by extrapolation of animal and human in vitro studies. There are no conclusive studies of human disease, and the cellular source of nitric oxide in human sepsis is not known. Haem oxygenase is upregulated by oxidative stress, but little is known about haem oxygenase expression in human sepsis. Haem oxygenase may modulate nitric oxide production, and may also have a direct effect on vascular tone.

METHODS

Mesenteric arterial smooth muscle (ASM) (obtained during laparotomy) and peripheral blood mononuclear cells (PBMCs) were obtained from patients with early septic shock and from control patients. mRNA levels were determined by real-time RT-PCR.

RESULTS

mRNA for inducible and endothelial nitric oxide synthase was reduced in both ASM and PBMCs from septic patients. In contrast, inducible haem oxygenase mRNA was increased in sepsis in both cell types.

CONCLUSIONS

These results suggest that, rather than being induced, the enzymes which produce nitric oxide are reduced at this time point in human septic shock. Thus many of the in vitro models of sepsis studied to date may not fully replicate human disease. The increase in haem oxygenase expression confirms that these cells have been subjected to oxidative stress in sepsis. The activity of induced haem oxygenase may limit nitric oxide production, while possibly causing vasodilation through production of carbon monoxide.

New method to evaluate the practice of positive pressure ventilation in intensive care units

BACKGROUND

There is good evidence to support the use of a "protective" ventilation strategy, using small tidal volumes and inspiratory pressures, in patients with acute respiratory distress syndrome. Many general intensive care units in the UK are being slow to adopt this approach and we therefore set out to devise a method to audit ventilation and possibly influence practice in these units.

METHODS

Using variables that are routinely documented by intensive care nurses, we assessed the relationship between ventilator settings and arterial blood gas values on 30 consecutive ventilated patients admitted to intensive care units at both a teaching and a district hospital. Data were recorded twice daily and the proportions of data points where there was unnecessary hyperventilation were recorded at each centre.

RESULTS

The initial audit results showed clear differences in practice between the teaching hospital and the district hospital. After an intensive education programme, during which an active role for nursing staff in ventilator management was encouraged, supported by simple protocols, practice in the district hospital was re-audited and found to closely mirror that in the teaching centre.

CONCLUSIONS

To assist progress towards the use of a "protective" ventilation strategy in intensive care units in the UK, we devised a simple, robust audit method. We have shown how this method can give a more uniform practice of ventilation in critical care units, with the introduction of nurse-run protocols.

Coupling of CFTR-mediated anion secretion to nucleoside transporters and adenosine homeostasis in Calu-3 cells

The purpose of this study was to characterize the role of adenosine-dependent regulation of anion secretion in Calu-3 cells. RT-PCR studies showed that Calu-3 cells expressed mRNA for A2A and A2B but not A1 or A3 receptors, and for hENT1, hENT2 and hCNT3 but not hCNT1 or hCNT2 nucleoside transporters. Short-circuit current measurements indicated that A2B receptors were present in both apical and basolateral membranes, whereas A2A receptors were detected only in basolateral membranes. Uptake studies demonstrated that the majority of adenosine transport was mediated by hENT1, which was localized to both apical and basolateral membranes, with a smaller hENT2-mediated component in basolateral membranes. Whole-cell current measurements showed that application of extracellular nitrobenzylmercaptopurine ribonucleoside (NBMPR), a selective inhibitor of hENT1-mediated transport, had similar effects on whole-cell currents as the application of exogenous adenosine. Inhibitors of adenosine kinase and 5'-nucleotidase increased and decreased, respectively, whole-cell currents, whereas inhibition of adenosine deaminase had no effect. Single-channel studies showed that NBMPR and adenosine kinase inhibitors activated CFTR Cl- channels. These results suggested that the equilibrative nucleoside transporters (hENT1, hENT2) together with adenosine kinase and 5'-nucleotidase play a crucial role in the regulation of CFTR through an adenosine-dependent pathway in human airway epithelia.