Rethinking sedation and agitation management in critical illness

OBJECTIVE

To examine difficulties in sedation management in the critically ill patient and explore how a semi automated sedation controller can improve agitation control. To present recent work on measurements of agitation, dynamic systems modelling and control of patient agitation response.

DATA SOURCES

Articles and peer-reviewed studies identified through a PUBMED search and selected original works from the biomedical engineering literature of relevance to agitation control and management.

SUMMARY OF REVIEW

Over-sedation has an adverse impact on intensive care resources. Interventions to constrain sedation delivery through development of protocols or regular cessation of infusions result in reduction in resource utilisation, but have not significantly addressed existing difficulties in agitation control. We develop a paradigm in which control of agitation in critically ill patients becomes the primary objective of sedation management. This principle is central to the function of a nurse-managed semi-automated sedation delivery device. The clinical application of this device using subjective assessments of agitation is presented. A framework for the development of improved automated sedation delivery systems using objective measurements of agitation and control, based on agitation feedback, is described. Using dynamic systems modelling and a simulated nurse, a bolus-driven approach significantly reduced agitation and minimised drug utilisation. This result challenges the current practice of sedating patients using continuous infusions.

CONCLUSIONS

A simple computerised interface with an algorithm that continually reduces the infusion rate in the absence of agitation has successfully been introduced into clinical practice. Nursing staff reported high levels of satisfaction with this device and it has enabled detailed data on patterns of sedation administration to be extracted for analysis. This data has been used to validate a model of the fundamental agitation-sedation dynamics.

Molecular genetic variation in the East Midlands, England: analysis of VNTR, STR and Alu insertion/deletion polymorphisms

BACKGROUND

Short tandem repeats (STRs) and variable number of tandem repeats (VNTRs) have been used successfully in disease analysis and studies of human evolution and population genetic diversity. However DNA-based comprehensive population genetic studies of the East Midlands, England are limited.

SUBJECTS AND METHODS

To enlarge our understanding of genetic variation in the East Midlands, a study was conducted on five regional populations: north-west Derbyshire,north-east Derbyshire, south Derbyshire, Nottinghamshire and Leicestershire. Blood samples were collected from donors whose ancestors had lived in the region for at least three generations. Seven VNTRs (MSI (DIS7), MS31 (D7S21), MS43A (D12SII) and YNH24 (D2S44), DIS0, APOB, YNZ22 (D17S5)), six STRs (HumTHOI, HumVWA31A, HumF13AOl1, HumFESFPS, HumCSFIPO, HumTPOX) and six Alu insertion/deletion polymorphisms (TPA25, ACE, PV92, F13B, APO, DI) were analysed in approximately 500 individuals. Allele or bin frequencies were calculated using gene counting and fixed bin methods. The chi-square method and exact tests were used to assess Hardy-Weinberg equilibrium. Genetic distances were calculated using Nei's DA method and correspondence analysis was used to assess population affinities.

RESULTS

The overall pattern of allele frequencies was similar to many European and UK populations for a number of genetic systems. Overall heterogeneity was observed for five loci: MS43A, MS31, HumF13A0l, HumFESFPS and HumTHOI. Twenty-three of 190 pairwise population comparisons were also statistically significant at the 5% level. Average molecular genetic system heterozygosity was 1.5 times higher than observed with conventional blood group systems. GsT values for molecular systems were also higher than conventional systems (0.012 vs 0.005) and suggest a low to moderate level of differentiation.

CONCLUSION

The allele frequency spectrum and inter-population comparisons show that there is significant genetic variation in the five contiguous regional populations of the East Midlands. Some of this variation may be due to local geographical barriers, genetic drift and possibly the settlement patterns of Continental European invaders.

Transanal endoscopic microsurgery and radical surgery for T1 and T2 rectal cancer

BACKGROUND

Transanal endoscopic microsurgery (TEM) has gained increasing acceptance as a local treatment of early rectal cancer. The purpose of this study was to compare the results of TEM and radical surgery in patients with T1 and T2 rectal cancer.

METHODS

From October 1994 to December 2000, 74 patients with T1 and T2 rectal adenocarcinoma treated with TEM were compared with 100 patients with T1N0M0 and T2N0M0 rectal adenocarcinoma treated with radical surgery. Retrospective analysis was performed regarding to recurrence and survival rate. Neither group received adjuvant chemoradiation. There was no significant difference in age, gender, tumor location, or follow-up period between the two groups. The only difference was in tumor size.

RESULTS

Of the 74 patients in TEM group, 52 were T1 (70.3%) and 22 were T2 (29.7%). Of the 100 patients in radical surgery group, 17 were T1 (17%) and 83 patients were T2 (83%). The 5-year local recurrence rates were 4.1% for T1, 19.5% for T2 after TEM, 0% for T1, and 9.4% for T2 after radical surgery. There was no statistical difference between the TEM and radical surgery groups for T1 rectal cancer ( p = 0.95), but for T2 rectal cancer, the 5-year local recurrence rate was higher after TEM than after radical surgery ( p = 0.04). There were no significant statistical difference between the two groups in terms of the 5-year disease-free survival rate and the survival rate.

CONCLUSIONS

For T1 rectal cancer, there was no difference in recurrence or 5-year survival rate between the TEM and the radical surgery groups. For T2 rectal cancer, there was no statistical difference in the 5-year survival rate between the two groups, but TEM carried higher risk of local recurrence. Therefore, careful selection of the patients is required for TEM, and when proper muscle invasion is proven, the TEM procedure should be supplemented by further treatment, or radical surgery should be performed.

Correlation of age, acromial morphology, and rotator cuff tear pathology diagnosed by ultrasound in asymptomatic patients

The importance of acromial morphology in the pathogenesis of rotator cuff tears remains controversial. Some surgeons place great emphasis on acromial morphology and others feel that acromial shape is a result of cuff tear pathology rather than the cause. The purpose of this study was to determine if there was an association between acromial morphology, age, and rotator cuff tears found by ultrasound in asymptomatic volunteer subjects with no past history of shoulder symptoms. One hundred eighteen outlet x-rays and ultrasound scans were performed in 59 asymptomatic patients in various age groups. Acromial morphology and the age of the patients were then correlated with the ultrasound findings. Older patients were noted to have a high incidence of type II and type III acromions (93% of those over 70). Full- and partial-thickness tears were more commonly seen in patients with type II or type III acromions compared with type I. Patients over 50 years had a high incidence of full-thickness tears (40%), but the incidence did not increase with increasing age past 50. These findings lend credence to the multifactorial etiology of rotator cuff tears. The patient's age (degeneration) and acromial morphology (impingement) are two of the factors involved in causing rotator cuff tears. The incidence of cuff tears and type III acromions was high in this group of entirely asymptomatic volunteer subjects. Surgeons should interpret radiologically hooked or curved acromions as well as rotator cuff tears diagnosed with ultrasound or other modalities with caution. It may well be that both of these findings should be regarded as part of the natural ageing process.

Comparison of the utility of barley retrotransposon families for genetic analysis by molecular marker techniques

The Sequence-Specific Amplification Polymorphism (S-SAP) method, and the related molecular marker techniques IRAP (inter-retrotransposon amplified polymorphism) and REMAP (retrotransposon-microsatellite amplified polymorphism), are based on retrotransposon activity, and are increasingly widely used. However, there have been no systematic analyses of the parameters of these methods or of the utility of different retrotransposon families in producing polymorphic, scorable fingerprints. We have generated S-SAP, IRAP, and REMAP data for three barley (Hordeum vulgare L.) varieties using primers based on sequences from six retrotransposon families (BARE-1, BAGY-1, BAGY-2, Sabrina, Nikita and Sukkula). The effect of the number of selective bases on the S-SAP profiles has been examined and the profiles obtained with eight MseI+3 selective primers compared for all the elements. Polymorphisms detected in the insertion pattern of all the families show that each can be used for S-SAP. The uniqueness of each transposition event and differences in the historic activity of each family suggest that the use of multiple retrotransposon families for genetic analysis will find applications in mapping, fingerprinting, and marker-assisted selection and evolutionary studies, not only in barley and other Hordeum species and related taxa, but also more generally.

[HUMANS: a neuropsychological battery for evaluating HIV 1 infected patients]

OBJECTIVE

To develop a neuropsychological test battery in Spanish for the cognitive evaluation of HIV 1 infected patients.

DEVELOPMENT

Departing from the suggestions presented by the work group of the National Institute of Mental Health (USA), a neuropsychological assessment battery was developed. It was named HUMANS (HIV/University of Miami Annotated Neuropsychological test battery in Spanish). This battery includes the following domains: 1) attention and speed of processing information, 2) memory, 3) executive function, 4) language, 5) visuospacial/visuoconstructive abilities, and 6) motor abilities. Administration takes about 3 4 hours. The English parallel version of this battery has been successfully used in English for over a decade with HIV 1 infected patients. In the paper the development and adaptation to Spanish language of the HUMANS neuropsychology section is presented.

CONCLUSIONS

HUMANS neuropsychological test battery fulfill the recommendations presented by the work group of the National Institute of Mental Health for evaluating HIV 1 infected patients. Studies regarding validity and reliability are still required.

The development of multiplex simple sequence repeat (SSR) markers to complement distinctness, uniformity and stability testing of rape (Brassica napus L.) varieties

To assess the potential of multiplex SSR markers for testing distinctness, uniformity and stability of rape (Brassica napus L.) varieties, we developed three multiplex SSR sets composed of five markers each. These were used to measure the extent of diversity within and between a set of ten varieties using a fluorescence-based semi-automated detection technology. Also, we evaluated the significance of any correlation between SSRs, pedigree and five of the morphological characters currently used for statutory distinctness, uniformity and stability testing of rape varieties. An assignment test was allowed to identify 99% of the plants examined, with the correct variety based on the analysis of 48 individual plants for each variety. Principal coordinate analysis confirmed that a high degree of separation between varieties could be achieved. Varieties were separated in three groups corresponding to winter, spring and forage types. These results suggested that it should be possible to select a set of markers for obtaining a suitable separation. Diversity within varieties varied considerably, according to the variety and the locus examined. No significant correlation was found between SSR and morphological data. However, genetic distances measured by SSRs were correlated to pedigree. These results suggested that SSRs could be used for pre-screening or grouping of existing and candidate varieties, allowing the number of varieties that need to be grown for comparison to be reduced. Multiplex SSR sets gave high-throughput reproducible results, thus reducing the costs of SSR assessment. Multiplex SSR sets are a promising way forward for complementing the current variety testing system in B. napus.

Generation of expression constructs that secrete bioactive alphaMSH and their use in the treatment of experimental autoimmune encephalomyelitis

alpha Melanocyte-stimulating hormone (alphaMSH) is a 13 amino acid peptide with potent anti-inflammatory effects. We created two DNA expression constructs (miniPOMC and pACTH1-17) that encode bioactive versions of the alphaMSH peptide, and tested these constructs for therapeutic effects in experimental autoimmune encephalomyelitis (EAE). Each construct contained the sequences for alphaMSH, as well as the sequences that are involved in the secretion and processing of the POMC gene with the assumption that these sequences would promote processing and release of the encoded alphaMSH peptide. The differences between the two constructs lie at the C-terminal end where amino acids necessary for amidation of alphaMSH were included in only the pACTH1-17 construct. These two constructs were tested in vitro in bioassays, and in vivo in a mouse model of EAE. The results show that although bioactive peptides are secreted from cells transfected with either construct, there appears to be a significant therapeutic effect only with the pACTH1-17 construct which contains the extra C-terminal amino acids. The data suggest that it is possible to engineer DNA expression vectors encoding small secreted peptides such as alphaMSH, and that similar type constructs may be useful as therapeutics for the treatment of inflammatory diseases.

Rheumatoid arthritis susceptibility and interleukin 10: a study of two ethnically diverse populations

INTRODUCTION

IL-10 is an immunoregulatory cytokine which may modulate disease expression in rheumatoid arthritis (RA). The IL-10 gene is highly polymorphic with a number of single nucleotide polymorphisms in the promoter region and two microsatellite loci, IL10.R and IL10.G, 4 kb and 1.1 kb 5' of the transcription initiation site. It has been reported that allele 2 of the IL10.R microsatellite (IL10.R2) is associated with increased IL-10 secretion and IL10.R3 with reduced secretion. Subsequently, over-representation of IL10.R2 and under-representation of IL10.R3 in three independent RA groups has been reported. The aim of the current study is to determine whether there is an association between the IL10.R2 allele and RA in two ethnically distinct populations.

METHODS

IL10.R genotypes were determined by semi-automated DNA sequencing technology in 186 UK Caucasians and 138 South Africans of Zulu or Sotho origin, fulfilling the 1987 American College of Rheumatology (ACR) criteria for RA. The Caucasian patients had relatively severe disease and comprised 75 patients with RA vasculitis, 22 with Felty's syndrome and 89 who had undergone a joint replacement (hip or knee) within 15 years of the onset of disease. Allele frequencies were compared with 296 Caucasians and/or 73 South Africans.

RESULTS

The frequency of the IL10.R2 allele was significantly greater in the South Africans (RA and controls) than in the Caucasians (0.78 vs 0.66, P=1 x 10(-6)), while the frequency of IL10.R3 was less common (0.16 vs 0.3, P=1 x 10(-8)). No differences were observed in either IL10.R2 or IL10.R3 frequencies between patients and controls in either population.

CONCLUSIONS

We were unable to confirm any association between IL10.R alleles and RA in this study. However, significant differences were demonstrated in the frequency of IL10.R2 and IL10.R3 between the two ethnic groups. The relatively high frequency of IL10.R2 in the South African population (0.78) would have reduced the power to detect an association with RA.

Numerical simulation of steady flow fields in a model of abdominal aorta with its peripheral branches

In the present study, a numerical calculation procedure based on a finite volume method was developed to simulate steady flow fields in a model of abdominal aorta with its peripheral branches. The study focused on the steady baseline flow fields and the wall shear stress (WSS) distribution as well as the localization of the reversed flow regions and results were compared to those obtained by other investigators. In the case of resting conditions, the existence of a region of reversed flow of about one to two diameters in size and next to the renal arteries and along the posterior wall as observed by other researchers was confirmed. However, under the exercise conditions this region could be wiped out. The flow reversal along the lateral walls proximal to the bifurcation persisted in both rest and exercise conditions. The WSS distribution and the wall shear stress gradient distribution were obtained. The lowest WSS occurred near the ostia of the renal arteries and the lateral walls of the iliac arteries. And the highest is always at the turn to the branch. The results were generally consistent with those obtained experimentally and numerically by other investigators. It was also shown that the steady flow might be used to depict the averaged behavior of pulsatile flow. The present computer code provides a platform for the future more realistic simulations.

Drug use, travel and HIV risk

A study was conducted to examine the travel experiences of a community sample of 160 drug users and 44 non-users recruited as part of a study of HIV risk. Of the sample, 47% (96/204) reported intercity travel in the previous ten years. Results showed that men were more likely to travel than women, Anglos more than minorities, and young persons more than old. When travellers testing HIV-seropositive (n = 13) were compared with seronegative travellers, HIV-positive travellers reported more sex while travelling than HIV-negative persons, but virtually all of the difference reported involved sex with condoms. There were no significant differences in sex risk behaviours while travelling between drug users and non-drug users, or in sex risk behaviors between drug injectors and non-injectors. Travellers had fewer injection partners while travelling than they had while at home. There was also a significant difference in number of sex partners with whom a condom was not used, with fewer sex partners while travelling.

Isolated extramedullary relapse in the pleural fluid of a patient with acute myeloid leukemia following allogeneic BMT

We report an unusual case of AML, in which the patient showed extramedullary relapse in the pleural fluid and the skin without bone marrow recurrence even 3 years after allogeneic BMT. On examination of the pleural effusion and the skin, which relapsed 31 months and 40 months, respectively, after BMT, we found that most of cells were as the XY-type recipient by quantitative X/Y FISH (fluorescence in situ hybridization). However, 100% of the bone marrow cells remained XX-type donor cells. In the present case, we believe that the graft-versus-leukemia (GVL) response in the extramedullary site was not so effective as that in the bone marrow, where it remains effective.

Low cumulative manganese exposure affects striatal GABA but not dopamine

The introduction of the anti-knock methylcyclopentadienyl manganese (Mn) tricarbonyl (MMT) in gasoline has raised concerns about the potential for manganese neurotoxicity. Because subpopulations such as the elderly in the early stages of neurodegenerative disease may be at increased risk for manganese toxicity, a pre-Parkinsonism rat model was used to evaluate whether sub-chronic manganese exposure can aggravate the neurochemical and behavioral dysfunctions characteristic of Parkinsonism. Sub-threshold levels of dopamine depletion of 3.5, 53 and 68% were generated via intrastriatal unilateral 6-hydroxydopamine (6-OHDA) doses. A sub-chronic dosing regimen of low cumulative manganese exposure (4.8 mg Mn/kg body weight, 3 i.p. injections per week x 5 weeks) was started 4 weeks after 6-OHDA treatments. Neurochemical and neuromotor (functional observational battery (FOB)) measures were evaluated. Manganese produced significant (P < 0.05) reductions of 30-60% in motor function. This effect was exacerbated in the presence of a pre-Parkinsonism condition [Neurotox. Teratol. 22 (2000) 851]. Manganese did not affect striatal dopamine, but resulted in significant increases in striatal y-aminobutyric acid (GABA) of 16 and 22% (P < 0.01) in both striati and a borderline non-significant 4% increase in frontal cortex (P = 0.076). Manganese treatment produced increased aspartate (P < 0.01) in the manganese and 6-OHDA treated striatum. In light of previous studies predominantly showing dopamine depletion with elevated manganese exposures, the significant effects of manganese on striatal GABA but not on striatal dopamine at the low cumulative exposure administered here suggest a progression in manganese toxicity with increasing cumulative dose, whereby GABA levels are adversely affected before striatal dopamine levels. Because these neurochemical disruptions were accompanied by motor dysfunction that was exacerbated in the presence of a pre-Parkinsonism condition, an increased environmental burden of manganese may have deleterious effects on populations with sub-threshold neurodegeneration in the basal ganglia (e.g. pre-Parkinsonism).

Incorporation of a fiber Bragg grating to improve the efficiency of a 1580-nm-band tunable fiber ring laser

An efficient and tunable 1580-nm-band erbium-doped fiber ring laser is achieved by injection of amplified spontaneous emission in a conventional band by a fiber Bragg grating into the gain medium. The insertion of the fiber Bragg grating reduces the lasing threshold to 25%. The tuning range is 1560-1610 nm; the side-mode suppression ratio is better than 65 dB.

Effects of risperidone on information processing and attention in first-episode schizophrenia

Risperidone appears to have a beneficial effect in several areas of cognitive function in schizophrenic patients. In previous studies, however, the clinical characteristics of the subjects differed between studies, and were heterogeneous even in single study. Most of the subjects were previously exposed to different kinds of neuroleptics and some of them were treatment-resistant. The aim of this study is to evaluate the effect of risperidone on attention and information processing in a homogeneous subgroup of schizophrenic patients, i.e. drug-naïve first-episode inpatients. In the patient group (n=17), cognitive tests and clinical assessments were performed before and after 8 weeks of risperidone treatment. The same cognitive tests were administered to the control group (n=24). The delay between test and retest was 8 weeks. Before treatment, the patient group performed significantly worse than control group on the tests measuring continuous attention, vigilance, and the speed of information processing. After treatment (the average dose of risperidone was 7.3mg/day), in spite of significant improvement of the clinical symptoms, the patients did not show any significant improvement or worsening in most of the items of these tests. The control group did not show any practice effect. These results suggest that first-episode schizophrenic patients have deficits in sustained attention and vigilance to visual stimuli, as well as the speed of information processing to visual and auditory stimuli, and these deficits are unrelated to clinical symptoms and remain stable during the early phase of treatment. This study did not receive pharmaceutical company financial support.