ABSTRACT
OBJECTIVES: To describe current UK clinical practice around the use of intrathecal diamorphine as analgesia for major elective laparoscopic colorectal surgery. DESIGN: Online self-administered survey. SETTING: Acute public hospitals in the UK (National Health Service - NHS) . PARTICIPANTS: Consultant anaesthetists involved in colorectal surgery lists. MAIN OUTCOME MEASURES: Rate of intrathecal opioids used by anaesthetists for elective laparoscopic colorectal procedures; minimum, most common and maximum doses of intrathecal diamorphine used, timing of administration of intrathecal injection, and relationship between the number of patients anaesthetised for laparoscopic colorectal resections per month by each anaesthetist, and the doses of intrathecal diamorphine they administer. RESULTS: In total, 479 responses were received. Of these, 399 (83%) use intrathecal opioid routinely: 351/399 (88%) use diamorphine, 35 (8.8%) use morphine, 8 (2%) use fentanyl, and 7 (1.3%) use other drugs. The median intrathecal diamorphine dose most commonly administered by anaesthetists was 500 µg (IQR 400-750 [(range 200-1500])). The median of the maximum dose administered by anaesthetists was 600 µg (IQR 500-1000 [(range 200-2000])). Greater intrathecal diamorphine dosing was positively associated with higher number of cases per month (rho=0.113, pp=0.033). CONCLUSIONS: Intrathecal diamorphine is widely used by UK anaesthetists for patients undergoing major elective laparoscopic colorectal surgery. However, there is little consensus regarding optimal dosing. Therefore, high-quality randomised dose-response trials are needed to investigate the relationship between doses of intrathecal diamorphine and patient outcomes.
Subject(s)
Analgesia , Colorectal Neoplasms , Colorectal Surgery , Analgesics, Opioid/therapeutic use , Cross-Sectional Studies , Heroin , Humans , Morphine/therapeutic use , Pain, Postoperative/drug therapy , State Medicine , United KingdomABSTRACT
Alzheimer's disease (AD) is associated with neuronal loss not only in the hippocampus and amygdala but also in the thalamus. Anterodorsal, centromedial, and pulvinar nuclei are the main sites of degeneration in AD. Here we combined shape analysis and diffusion tensor imaging (DTI) tractography to study degeneration in AD in the thalamus and its connections. Structural and diffusion tensor MRI scans were obtained from 16 AD patients and 22 demographically similar healthy volunteers. The thalamus, hippocampus, and amygdala were automatically segmented using our locally developed algorithm, and group comparisons were carried out for each surface vertex. We also employed probabilistic diffusion tractography to obtain connectivity measures between individual thalamic voxels and hippocampus/amygdala voxels and to segment the internal medullary lamina (IML). Shape analysis showed significant bilateral regional atrophy in the dorsal-medial part of the thalamus in AD patients compared to controls. Probabilistic tractography demonstrated that these regions are mainly connected with the hippocampus, temporal, and prefrontal cortex. Intrathalamic FA comparisons showed reductions in the anterodorsal region of thalamus. Intrathalamic tractography from this region revealed that the IML was significantly smaller in AD patients than in controls. We suggest that these changes can be attributed to the degeneration of the anterodorsal and intralaminar nuclei, respectively. In addition, based on previous neuropathological reports, ventral and dorsal-medial shape change in the thalamus in AD patients is likely to be driven by IML atrophy. This combined shape and connectivity analysis provides MRI evidence of regional thalamic degeneration in AD.
Subject(s)
Alzheimer Disease/pathology , Neural Pathways/pathology , Thalamic Diseases/pathology , Aged , Alzheimer Disease/complications , Alzheimer Disease/psychology , Diffusion Magnetic Resonance Imaging , Female , Functional Laterality/physiology , Humans , Image Processing, Computer-Assisted , Linear Models , Male , Middle Aged , Nerve Degeneration/pathology , Nerve Degeneration/psychology , Neuropsychological Tests , Psychomotor Performance/physiology , Socioeconomic Factors , Thalamic Diseases/etiology , Thalamic Diseases/psychologyABSTRACT
BACKGROUND AND PURPOSE: Considerable clinical and radiological overlap between vascular dementia (VaD) and Alzheimer disease (AD) often makes the diagnosis difficult. Diffusion-tensor imaging studies showed that fractional anisotropy (FA) could be a useful marker for white matter changes. This study aimed to identify regional FA changes to identify a biomarker that could be used to differentiate VaD from AD. METHODS: T1-weighted and diffusion-tensor imaging scans were obtained in 13 VaD patients, 16 AD patients, and 22 healthy elderly controls. We used tract-based spatial statistics to study regional changes in fractional anisotropy in AD, VaD, and elderly controls. We then used probabilistic tractography to parcel the corpus callosum in 7 regions according to its connectivity with major cerebral cortices using diffusion-tensor imaging data set. We compared the volume and mean FA in each set of transcallosal fibers between groups using ANOVA and then applied a discriminant analysis based on FA and T2-weighted imaging measures. RESULTS: FA reduction in forceps minor was the most significant area of difference between AD and VaD. Segmentation of the corpus callosum using tractography and comparison of FA changes of each segment confirmed the FA changes in transcallosal prefrontal tracts of patients with VaD when compared to AD. The best discriminant model was the combination of transcallosal prefrontal FA and Fazekas score with 87.5% accuracy, 100% specificity, and 93% sensitivity (P<0.0001). CONCLUSIONS: Integrating mean FA in the forceps minor to the Fazekas score provides a useful quantitative marker for differentiating AD from VaD.
