Mortality and readmission rates of patients discharged in-hours and out-of-hours from a British ICU over a 3-year period

Excess in-hospital mortality following out-of-hours ICU discharge has been reported worldwide. From preliminary data, we observed that magnitude of difference may be reduced when patients discharged for end-of-life care or organ donation are excluded. We speculated that these patients may be disproportionately discharged out-of-hours, biasing results. We now compare in-hospital mortality and ICU readmission rates following discharge in-hours and out-of-hours over 3 years, excluding discharges for organ donation or end-of-life care. This single-centre retrospective study includes patients discharged alive following ICU admission between 01/07/2015–31/07/2018, excluding readmissions and discharges for end-of-life care/organ donation. A multiple logistic regression model was fitted to estimate adjusted odds ratio of death following out-of-hours versus in-hours discharge. Characteristics and outcomes for both groups were compared. 4678 patients were included. Patients discharged out-of-hours were older (62 vs 59 years, p < 0.001), with greater APACHE II scores (15.7 vs 14.4, p < 0.001), length of ICU stay (3.25 vs 3.00 days, p = 0.01) and delays to ICU discharge (736 vs 489 min, p < 0.001). No difference was observed in mortality (4.6% vs 3.7%, p = 0.25) or readmission rate (4.1% vs 4.2%, p = 0.85). In the multiple logistic regression model out-of-hours discharge was not associated with in-hospital mortality (OR = 1.017, 95% CI 0.682–1.518, p = 0.93). Our findings present a possible explanation for reported excess mortality following out-of-hours ICU discharge, related to inclusion of organ donation and end-of-life care patients in data sets rather than standards of care delivered out-of-hours. We are not aware of any other studies investigating the influence of this group on reported post-ICU mortality rates.

Von Willebrand factor (vWF): marker of endothelial damage and thrombotic risk in COVID-19?

BACKGROUND

COVID-19 infection is characterised, among other features, by a prothrombotic state with high rate of venous thromboembolism (VTE), D-dimer, and fibrinogen levels. Clinical observations have also highlighted that these patients have elevated von Willebrand factor (vWF) and factor VIIIc.

METHODS

24 consecutive COVID-19 positive patients were selected from the intensive care unit (ICU) or the high acuity ward of Brighton and Sussex University Hospitals NHS Trust.

RESULTS

The rate of VTE was 25% and mortality rate was 16.7%. Fibrinogen and D-Dimers were elevated, 7.9 (1.6) g/L and 2.4 (2.02) ug/ml respectively. Factor VIIIc and von vWF antigen levels were both extremely elevated at 279 (148) u/dL and 350 (131) % respectively, which are comparable to levels seen in ICU patients with severe sepsis. vWF levels were significantly higher in patients that died (p=0.017) and showed a positive correlation with age. There was a statistically significant association between COVID-19 disease and non-O blood group (p=0.02); 80% (4/5) of COVID-19 patients with VTE were blood group A.

CONCLUSION

Very high levels of vWF and factor VIIIc are common in COVID-19 patients, comparable to levels in severely septic non-COVID ICU patients. This could contribute to the hypercoagulable state and increased VTE rate in COVID-19. Further studies are needed to evaluate the use of vWF for stratifying thrombotic risk in COVID-19 and to determine if elevated vWF is contributing to disease pathogenesis.

Scaling beta-lactam antimicrobial pharmacokinetics from early life to old age

AIMS

Beta-lactam dose optimization in critical care is a current priority. We aimed to review the pharmacokinetics (PK) of three commonly used beta-lactams (amoxicillin ± clavulanate, piperacillin-tazobactam and meropenem) to compare PK parameters reported in critically and noncritically ill neonates, children and adults, and to investigate whether allometric and maturation scaling principles could be applied to describe changes in PK parameters through life.

METHODS

A systematic review of PK studies of the three drugs was undertaken using MEDLINE and EMBASE. PK parameters and summary statistics were extracted and scaled using allometric principles to 70 kg individual for comparison. Pooled data were used to model clearance maturation and decline using a sigmoidal (Hill) function.

RESULTS

A total of 130 papers were identified. Age ranged from 29 weeks to 82 years and weight from 0.9-200 kg. PK parameters from critically ill populations were reported with wider confidence intervals than those in healthy volunteers, indicating greater PK variability in critical illness. The standard allometric size and sigmoidal maturation model adequately described increasing clearance in neonates, and a sigmoidal model was also used to describe decline in older age. Adult weight-adjusted clearance was achieved at approximately 2 years postmenstrual age. Changes in volume of distribution were well described by the standard allometric model, although amoxicillin data suggested a relatively higher volume of distribution in neonates.

CONCLUSIONS

Critical illness is associated with greater PK variability than in healthy volunteers. The maturation models presented will be useful for optimizing beta-lactam dosing, although a prospective, age-inclusive study is warranted for external validation.

Xenobiotic metabolism: the effect of acute kidney injury on non-renal drug clearance and hepatic drug metabolism

Acute kidney injury (AKI) is a common complication of critical illness, and evidence is emerging that suggests AKI disrupts the function of other organs. It is a recognized phenomenon that patients with chronic kidney disease (CKD) have reduced hepatic metabolism of drugs, via the cytochrome P450 (CYP) enzyme group, and drug dosing guidelines in AKI are often extrapolated from data obtained from patients with CKD. This approach, however, is flawed because several confounding factors exist in AKI. The data from animal studies investigating the effects of AKI on CYP activity are conflicting, although the results of the majority do suggest that AKI impairs hepatic CYP activity. More recently, human study data have also demonstrated decreased CYP activity associated with AKI, in particular the CYP3A subtypes. Furthermore, preliminary data suggest that patients expressing the functional allele variant CYP3A5*1 may be protected from the deleterious effects of AKI when compared with patients homozygous for the variant CYP3A5*3, which codes for a non-functional protein. In conclusion, there is a need to individualize drug prescribing, particularly for the more sick and vulnerable patients, but this needs to be explored in greater depth.

Newborn hearing screening and cochlear implantation: impact on spoken language development

OBJECTIVES

This study retrospectively evaluates the effect of newborn hearing screening on age at diagnosis, age at cochlear implantation and spoken language development in severely hearing-impaired children.

METHODS

Age at diagnosis, age at cochlear implantation and language development were evaluated in a group of early screened (n = 149) and a group of late screened (n = 139) severely hearing-impaired children. Language outcomes were quantified as language quotients (LQs) on the Reynell Developmental Language Scales and Schlichting Expressive Language Test at 1,2, and 3 years after cochlear implantation.

RESULTS

Early screened children were significantly younger than late screened children at the time of hearing loss diagnosis and cochlear implantation. Furthermore, early screening was associated with better receptive and expressive spoken language skills after cochlear implantation.

CONCLUSION

The results of this retrospective study indicate that the newborn hearing screening program in Flanders and The Netherlands resulted in earlier intervention in deaf children, which beneficially influenced spoken language development.

Using drug probes to monitor hepatic drug metabolism in critically ill patients: midazolam, a flawed but useful tool for clinical investigation of CYP3A activity?

IMPORTANCE OF THE FIELD

In the UK, acute kidney injury (AKI) occurs in 25% of patients admitted to intensive care. Outcome is worsened in the presence of AKI for reasons not easily explained. AKI unpredictably affects the pharmacokinetics and pharmacodynamics of drugs and dosing in patients with AKI is largely based on data from chronic kidney disease patients, but how appropriately is unknown.

AREAS COVERED IN THIS REVIEW

Midazolam as a drug probe of CYP3A activity is reviewed, with discussion of its limitations and alternatives in critically ill patients. Pharmacogenetics of CYP3A enzymes and their significance are discussed and emerging evidence that AKI affects liver metabolism is reviewed.

WHAT THE READER WILL GAIN

The aim is to give the reader insight into the complexities of in vivo research in critically ill patient with discussion of interaction between the kidney and liver. We explain the use of midazolam as a drug probe for the investigation of the effect of AKI on hepatic function.

TAKE HOME MESSAGE

Critically ill patients are difficult to manage but methods are now available for investigation of complex interrelationships that complicate the care and management of these patients with the potential to improve safety, efficacy and outcome, particularly for drug administration.

The interpretation of brain natriuretic peptide in critical care patients; will it ever be useful?

The measurement of B-type natriuretic peptide (BNP) is recommended for the diagnosis of decompensated heart failure, the prognosis of chronic heart failure is worse if BNP is increased and studies suggest that BNP is useful to guide therapy. A study by Di Somma and colleagues adds to the body of evidence showing that patients with a marked decrease in BNP concentrations during their hospital admission are less likely to be readmitted with a further adverse cardiac event than patients in whom BNP fails to decrease. However, the wider interpretation of BNP concentrations in critically ill patients with other conditions remains uncertain.

Triaging for adult critical care in the event of overwhelming need

INTRODUCTION

Predictions of the need for critical care within the H1N1 influenza pandemic suggested overwhelming need beyond potential resources, necessitating rationing of care via triaging.

METHOD

The triage model described was derived from informed discourse within a conjoined NHS and University Clinical Ethics Committee, supplemented by specialists in intensive care and infectious diseases. THE MODEL: The triage methodology described is justified ethically primarily upon 'utilitarian' principles within an aggregate public health model, with additional reference to 'fairness'. Advantages of such a model, which partially suspends usual clinical judgment applied to individuals in favour of also utilizing organ failure scores, include minimization of aggregate influenza morbidity and mortality, and minimization of psychological stress upon staff making triaging decisions. Legally, in England and Wales, the model is uncontentious as regards rationing of admission to critical care; however, the law adopts 'futility' as the core justification for withdrawal of treatment, applied to the individual, thus failing to allow for rationing through triaging individuals out of critical care in the interest of other patients with better chances of survival. There is therefore a mismatch between a clinically and ethically acceptable model of triaging, based upon a public health approach, and the law, based upon the paradigm of the individual patient.

CONCLUSION

The good fortune that the H1N1 pandemic was less severe than predicted, allowing time for calm consideration, debate and decision making about what model of triaging should be adopted whenever it might be necessary in the future. It is in the interest of the health of the nation, and government, to decide upon a critical care triaging model while there is not an imminent health service crisis.

Idiopathic pulmonary fibrosis associated with pulmonary vein thrombosis: a case report

Background

Pulmonary vein thrombosis represents a potentially fatal disease. This syndrome may clinically mimic pulmonary embolism but has a different investigation strategy and prognosis. Pulmonary vein thrombosis is difficult to diagnose clinically and usually requires a combination of conventionally used diagnostic modalities.

Case Presentation

The authors report a case of a 78-year-old previously healthy female presenting with collapse and shortness of breath. Serum biochemistry revealed acute kidney injury, positive D-dimmer's and increased C reactive protein. Chest radiography demonstrated volume loss in the right lung. The patient was started on antibiotics and also therapeutic doses of low molecular weight heparin. The working diagnosis included community acquired pneumonia & pulmonary embolism. A computed tomography pulmonary angiogram was performed to confirm the clinical suspicions of pulmonary embolism. This demonstrated a thrombus in the pulmonary vein, with associated fibrosis and volume loss of the right lower lobe. A subsequent thrombophilia screen revealed a positive lupus anticoagulant antibody and rheumatoid factor and also decreased anti thrombin III and protein C levels. The urine protein/creatinine ratio was found to be 553 mg/mmol.

Conclusion

The diagnosis of this patient was therefore of idiopathic pulmonary fibrosis associated with pulmonary vein thrombosis. Whether or not the pulmonary vein thrombosis was a primary cause of the fibrosis or a consequence of it was unclear. There are few data on the management of pulmonary vein thrombosis, but anticoagulation, antibiotics, and, in cases of large pulmonary vein thrombosis, thrombectomy or pulmonary resection have been used.

Temperature measurement: comparison of non-invasive methods used in adult critical care

AIMS AND OBJECTIVES

To assess accuracy and reliability of two non-invasive methods, the chemical (Tempa.DOT) and tympanic thermometer (Genius First Temp M3000A), against the gold standard pulmonary artery catheter, and to determine the clinical significance of any temperature discrepancy using an expert panel.

BACKGROUND

There is continued debate surrounding the use of tympanic thermometry in clinical practice.

DESIGN

Prospective study.

METHODS

A total of 160 temperature sets were obtained from 25 adult intensive care patients over a 6-month period.

RESULTS

About 75.2% (n = 115) of chemical and 50.9% (n = 78) of tympanic readings were within a +/-0.0-0.4 degrees C range of the pulmonary artery catheter. Both the chemical and tympanic thermometers were significantly correlated with temperatures derived from the pulmonary artery catheter (r = 0.81, P < 0.0001 and r = 0.59, P < 0.0001) and limits of agreement were -0.5-0.9 degrees C and -1.2-1.2 degrees C respectively. The chemical thermometer was associated with a mean temperature difference of 0.2 degrees C, which increased 0.4 degrees C when used in conjunction with a warming blanket. With regard to clinical significance 15.3% (n = 26) of chemical and 21.1% (n = 35) of tympanic readings might have resulted in patients receiving delayed interventions. Conversely 28.8% (n = 44) of chemical and 37.8% (n = 58) of tympanic readings might have resulted in patients receiving unnecessary interventions.

CONCLUSIONS

The chemical thermometer was more accurate, reliable and associated with fewer clinically significant temperature differences compared with the tympanic thermometer. However, compared with the pulmonary artery catheter both methods were associated with erroneous readings. In the light of these findings and previous research evidence, it is becoming increasingly difficult to defend the continued use of tympanic thermometry in clinical practice. However, as chemical thermometers are not without their limitations, further research needs to be undertaken to evaluate the accuracy and reliability of other non-invasive methods.

RELEVANCE TO CLINICAL PRACTICE

Chemical and tympanic thermometers are used in both adults and children in a wide variety of settings ranging from community to intensive care. As such these findings have significant implications for patients, users and budget holders.

Recurrent 'sterile' verrucous cyst abscesses and epidermodysplasia verruciformis-like eruption associated with idiopathic CD4 lymphopenia

Rupture of follicular (epidermoid) cysts is believed to be the consequence of bacterial infection. We report a 24-year-old man with idiopathic CD4 lymphopenia and chronic Mycobacterium avium intracellulare infection who developed multiple, recurring painful abscesses over the distal extremities that increased in number and severity when systemic steroid and interferon-gamma treatment was instituted for interstitial lung disease. Cultures were consistently negative for microorganisms, but pathological examination revealed ruptured epidermoid cyst walls with human papillomavirus (HPV) viropathic changes (keratinocytes with perinuclear halos and abundant basophilic keratohyaline granules). Cutaneous examination showed numerous, widespread flat-topped papules and achromic macules over the extremities, head and neck. Nested polymerase chain reaction analysis for HPV DNA revealed that the abscess-related cyst walls harboured epidermodysplasia verruciformis (EV)-associated HPV types 20, 24, alb-7 (AY013872) and 80. His cutaneous lesions harboured HPV types 3, 8 and 80. Similar to past reports, our patient developed an EV-like eruption in the setting of immunodeficiency. In this instance, EV-associated HPV infection of the follicular infundibular epithelium or pre-existing cysts in the setting of immunodeficiency may have led to cystic growth, rupture and subsequent painful inflammation.

Effect of irradiation, packaging, and postirradiation cooking on the thiamin content of chicken meat

The effect of irradiation with X rays or electrons, irradiation and storage temperature, and postirradiation cooking on the thiamin content of vacuum- or air-packaged minced chicken meat was examined. Samples irradiated with 3-kGy X rays (50 Gy/min) or electrons (5 kGy/min) contained less thiamin than the control specimens, but no differences between both irradiation methods were detected. The thiamin content in samples stored and/or irradiated at 5 degrees C was between 13 and 24 microg per 100-g product lower than in samples stored and/or ionized at -18 degrees C. The same difference in thiamin content was found for specimens packaged in a vacuum or air package, respectively. Vacuum packaging lead to a greater loss of drip than air-packaged samples. The biggest loss of thiamin, 31.1 and 28.0% for X rays and electron beams, respectively, was measured for vacuum-packaged specimens stored and irradiated at 5 degrees C. Compared with the cooked minced chicken breast meat, a higher thiamin content (6 to 17 microg of thiamin per 100-g product) was obtained for the raw samples. When irradiation and vacuum packaging were compared as two separate preservation techniques, the two methods had approximately the same effect on the thiamin content of the minced chicken meat. The mean temperature of the samples after cooking was 87.2 +/- 4.9 degrees C. However, significant differences in internal temperature after cooking of the samples were measured between air- and vacuum-packaged samples.