Autism-friendly MRI: Improving radiography practice in the UK, a survey of radiographer practitioners.

INTRODUCTION: Autistic individuals undergoing magnetic resonance imaging (MRI) examinations may face significant challenges, mainly due to sensory overload and MRI environment-related limitations. This study aimed to explore radiographers' perspectives and experiences regarding MRI scanning of autistic individuals. METHODS: Data collection was achieved using a specifically designed mixed methods questionnaire on Qualtrics. The snowball technique was used. This UK-wide survey was electronically distributed by three main recruitment agencies between December 2020 and February 2021. RESULTS: 130 valid responses were received. A lack of relevant training and knowledge related to autism was noted. Effective communication, optimisation and customisation of the MRI examination, and MRI environment adjustments facilitated the completion of a safe and effective MRI examination. Poor patient-radiographer communication, unavailability of Special Educational Needs (SEN) experts, lack of specialised radiographer training and lack of specific guidelines were identified as the main barriers to successful MRI examinations. CONCLUSION: Although routine MRI safety and patient care rules will apply, MRI scanning of autistic individuals requires customisation and reasonable adjustments in communication, environment, and training of clinical teams. In addition, guidelines should be established to be used as a reference point to improve clinical practice. The adjustments proposed by radiographers were all consistent with the interventions in the wider literature. IMPLICATIONS FOR PRACTICE: MRI practice for personalised care of autistic individuals should be aligned with current evidence, to customise communication and offer workflow and environmental adjustments. Formal training related to autism, integrated within radiography academic curricula and better co-ordination and communication of interdisciplinary teams would provide the necessary skill mix to deliver safe, high quality MRI scans with optimal experience for autistic service users and their carer(s).

The influence of propofol and sevoflurane on intestinal motility during laparoscopic surgery.

BACKGROUND: Volatile anaesthetics have an influence on small bowel peristalsis during laparoscopic surgery. A recent study concluded that desflurane increased intestinal motility compared to sevoflurane. Hence, a desflurane-based anaesthesia protocol may reduce surgical exposure during intestinal suturing or stapling due to small bowel hyperperistalsis. The effect of propofol on intestinal motility is not well studied. We tested the hypothesis that a propofol-remifentanil anaesthesia increases intestinal contractions in comparison with a sevoflurane-remifentanil anaesthesia. METHODS: Patients scheduled for laparoscopic gastric bypass surgery were randomized in this single blind randomized controlled trial to receive remifentanil combined with sevoflurane or propofol (ISRCTN 12921661). Bispectral index monitoring was used to guide depth of anaesthesia. Visual observation of peristaltic waves was performed during 1 min at the planned site of the jejunostomy. Statistical analysis was performed using Wilcoxon two-sample test. RESULTS: After obtaining written informed consent 50 patients were included. Groups were similar for demographic variables, and depth of anaesthesia during the observations. The median number of peristaltic waves was lower in the sevoflurane-remifentanil group compared to the propofol-remifentanil group (0 vs. 6, P < 0.001). CONCLUSION: Propofol-remifentanil increases intestinal motility compared with sevoflurane-remifentanil during laparoscopic gastric bypass surgery. A sevoflurane-based protocol can help to avoid disturbing peristalsis.

I.V. and perineural dexamethasone are equivalent in increasing the analgesic duration of a single-shot interscalene block with ropivacaine for shoulder surgery: a prospective, randomized, placebo-controlled study.

BACKGROUND: Interscalene brachial plexus block (ISB) provides excellent, but time-limited analgesia. Dexamethasone added to local anaesthetics prolongs the duration of a single-shot ISB. However, systemic glucocorticoids also improve postoperative analgesia. The hypothesis was tested that perineural and i.v. dexamethasone would have an equivalent effect on prolonging analgesic duration of an ISB. METHODS: We performed a prospective, double blind, randomized, placebo-controlled study. Patients presenting for arthroscopic shoulder surgery with an ISB were randomized into three groups: ropivacaine 0.5% (R); ropivacaine 0.5% and dexamethasone 10 mg (RD); and ropivacaine 0.5% with i.v. dexamethasone 10 mg (RDiv). The primary outcome was the duration of analgesia, defined as the time between performance of the block and the first analgesic request. Standard hypothesis tests (t-test, Mann-Whitney U-test) were used to compare treatment groups. The primary outcome was analysed by Kaplan-Meier survival analysis with a log-rank test and Cox's proportional hazards regression. RESULTS: One hundred and fifty patients were included after obtaining ethical committee approval and patient informed consent. The median time of a sensory block was equivalent for perineural and i.v. dexamethasone: 1405 min (IQR 1015-1710) and 1275 min (IQR 1095-2035) for RD and RDiv, respectively. There was a significant difference between the ropivacaine group: 757 min (IQR 635-910) and the dexamethasone groups (P<0.0001). CONCLUSIONS: I.V. dexamethasone is equivalent to perineural dexamethasone in prolonging the analgesic duration of a single-shot ISB with ropivacaine. As dexamethasone is not licensed for perineural use, clinicians should consider i.v. administration of dexamethasone to achieve an increased duration of ISB.

Randomized clinical trial on the influence of anaesthesia protocol on intestinal motility during laparoscopic surgery requiring small bowel anastomosis.

BACKGROUND: Hyperperistalsis of the small bowel during laparoscopic surgery may cause mucosal prolapse and reduce exposure, making laparoscopic suturing or stapling more demanding for the surgeon. Although it is commonly accepted that both opioids and volatile anaesthetics induce intestinal paralysis, intestinal hyperactivity during anaesthesia is not uncommon. This randomized trial investigated the effect of different volatile anaesthetics on intestinal motility and the impact on surgeon satisfaction. METHODS: Patients scheduled for laparoscopic gastric bypass surgery were randomized to receive sevoflurane or desflurane in a balanced anaesthetic regimen. After surgical exposure peristaltic waves were counted over 1 min in a segment of the jejunum. Following evaluation of intestinal motility, N-butylhyoscine, an antimuscarinic anticholinergic agent that relaxes bowel smooth muscle cells, could be administered if the surgeon judged the intestinal motility as disturbing. The endpoints were number of peristaltic waves and incidence of N-butylhyoscine administration, a surrogate for surgeon satisfaction. RESULTS: Twenty-two patients were randomized to each group. The groups were similar in age, sex and body mass index. There was a statistically significant difference in intestinal motility between the desflurane and sevoflurane groups: median (range) 7 (0-12) versus 1 (0-10) waves counted over 1 min respectively (P < 0·001). A higher proportion of patients in the desflurane group received N-butylhyoscine (10 of 22 versus 1 of 22 in the sevoflurane group; P = 0·004). CONCLUSION: Desflurane increased intestinal motility and decreased surgeon satisfaction compared with sevoflurane during laparoscopic gastric bypass surgery. A sevoflurane-based anaesthetic protocol can help to avoid disturbing hyperperistalsis. REGISTRATION NUMBER: B39620097060 (http://www.clinicaltrials.be).

A comparison of methods for assessing total arterial compliance.

There are several methods of assessing total arterial compliance (TAC) based on the two element Windkessel model, which is a ratio of pressure and volume, but the optimal technique is unclear. In this study, three methods of estimating TAC were compared to determine which was the most robust in a large group of patients with and without cardiovascular risk. In all, 320 patients (170 men; age 55+/-10) were studied; TAC was determined by the pulse-pressure method (PPM), the area method (AM) and the stroke volume/pulse-pressure method (SVPP). We obtained arterial waveforms using radial applanation tonometry, dimensions using two-dimensional echocardiography and flow data by Doppler. Clinical data, risk factors, echo parameters and TAC by all three methods were then compared. TAC (ml mm Hg(-1)) by the PPM was 1.24+/-0.51, by the AM 1.84+/-0.90 and by the SVPP 1.96+/-0.76 (P<0.0001 between groups). Correlation was good between all methods: PPM/AM r=0.83, PPM/SVPP r=0.94 and AM/SVPP r=0.80 (all P<0.0001). Subgroup analysis showed significant differences between patients with and those without cardiovascular risk for all three methods; TAC-AM and TAC-SVPP values were similar and significantly higher than TAC-PPM. The only significant relationships observed with TAC and echo parameters were in left ventricular (LV) septal thickness (R(2)=0.07; P<0.0001) and LV mass (R(2)=0.04; P=0.004). Normal and abnormal values of TAC vary according to method, which should be expressed. Each of the techniques shows good correlation with each other, however, values for TAC-PPM are significantly lower. TAC-PPM and TAC-SVPP are comparable in determining differences between groups with and without cardiovascular risk.

Perioperative management of phaeochromocytoma.

Phaeochromocytoma is a rare catecholamine producing tumour, feared for its life threatening cardiovascular disturbances during anaesthesia. Improved medical and anesthetic management resulted in reduction of perioperative phaeochromocytoma resection mortality from about 50% in the pioneer period to near 0% nowadays. Cardiomyopathy is usually reversible if managed properly. Stress related or (inverted) Tako Tsubo cardiomyopathy is a recent finding, deserving our attention. Preoperative alpha blockade should be performed to achieve cardiovascular stability and decrease uncontrolled intraoperative surges in blood pressure. During anaesthesia, additional antihypertensive (also mainly alpha blocking) agents are essential to prevent and overcome hypertensive crises. Magnesium sulphate is a safe and promising agent in improving cardiovascular stability and should have a place in standard therapy. A careful selection of anaesthetic drugs and techniques that cause the least hypertension is most important. Preoperative and intraoperative beta-blockade can only be used as adjuvant therapy, mainly to control tachycardia and other rhythm disturbances. Postoperatively, the patient is transferred to the intensive care unit where adequate management of haemodynamic and metabolic complications takes place.

Numerical study of the uniformity of balloon-expandable stent deployment.

Stents are small tubelike structures, implanted in coronary and peripheral arteries to reopen narrowed vessel sections. This endovascular intervention remains suboptimal, as the success rate is limited by restenosis. This renarrowing of a stented vessel is related to the arterial injury caused by stent-artery and balloon-artery interactions, and a local subsequent inflammatory process. Therefore, efforts to optimize the stent deployment remain very meaningful. Several authors have studied with finite element modeling the mechanical behavior of balloon-expandable stents, but none of the proposed models incorporates the folding pattern of the balloon. We developed a numerical model in which the CYPHER stent is combined with a realistic trifolded balloon. In this paper, the impact of several parameters such as balloon length, folding pattern, and relative position of the stent with respect to the balloon catheter on the free stent expansion has been investigated. Quantitative validation of the modeling strategy shows excellent agreement with data provided by the manufacturer and, therefore, the model serves as a solid basis for further investigations. The parametric analyses showed that both the balloon length and the folding pattern have a considerable influence on the uniformity and symmetry of the transient stent expansion. Consequently, this approach can be used to select the most appropriate balloon length and folding pattern for a particular stent design in order to optimize the stent deployment. Furthermore, it was demonstrated that small positioning inaccuracies may change the expansion behavior of a stent. Therefore, the placement of the stent on the balloon catheter should be accurately carried out, again in order to decrease the endothelial damage.

First trimester anesthesia exposure and fetal outcome. A review.

Approximately 0.5-2% of all pregnant women undergo nonobstetric surgery during their pregnancy. This percentage does not include patients who are in the early phase of gestation and are not aware of it at the time of surgery. When pregnancy is diagnosed, the concern raises whether surgery and anesthesia during early gestation pose hazard to the developing fetus, by increasing the risk of congenital anomalies and spontaneous abortion. Literature review suggests that there is no increase in congenital anomalies at birth in women who underwent anesthesia during pregnancy. However, first trimester anesthesia exposure does increase the risk of spontaneous abortion and lower birth weight. This is more likely due to surgical manipulation and the medical condition that necessitates surgery than to the exposure to anesthesia.

Coronary microvascular dysfunction after myocardial infarction: increased coronary zero flow pressure both in the infarcted and in the remote myocardium is mainly related to left ventricular filling pressure.

OBJECTIVE: To investigate the underlying mechanisms of a decreased coronary flow reserve after myocardial infarction (MI) by analysing the characteristics of the diastolic hyperaemic coronary pressure-flow relationship. DESIGN: Prospective study. SETTING: Tertiary care hospital. PATIENTS: 68 patients with a recent MI and 27 patients with stable angina pectoris (AP; control group). MAIN OUTCOME MEASURES: The intercept with the pressure axis (the zero flow pressure or Pzf) and slope index of the pressure-flow relationship (SIPF) were calculated from the simultaneously recorded hyperaemic intracoronary blood flow velocity and aortic pressure after successful coronary stenting. RESULTS: A stepwise increase in Pzf from AP (14.6 (8.0) mm Hg), over non-Q-wave MI (22.5 (9.1) mm Hg), to Q-wave MI (37.1 (12.9) mm Hg; p<0.001) was observed. Similar changes in Pzf were found in a reference artery perfusing the non-infarcted myocardium. Multivariate analysis showed that in both regions the left ventricular end-diastolic pressure (LVEDP) was the most important determinant of the Pzf. The SIPF was not statistically different in the treated vessel between patients with MI and AP, but was increased in MI patients with a markedly increased LVEDP. CONCLUSIONS: After an MI, the coronary pressure-flow relationship is shifted to the right both in the infarcted and in the non-infarcted remote myocardium, as shown by the increased Pzf. The correlation with Pzf suggests that elevated left ventricular filling pressures contribute to the impediment of myocardial perfusion in patients with infarction.

Influence of arterial compliance on presence and extent of ischaemia during stress echocardiography.

OBJECTIVE: To seek an association between total arterial compliance (TAC) and the extent of ischaemia at stress echocardiography. DESIGN: Cohort study. SETTING: Regional cardiac centre. METHODS: 255 consecutive patients (147 men; mean (SD) age 58 (8)) presenting for stress echocardiography for clinical indications were studied. Wall motion score index (WMSI) was calculated and ischaemia was defined by an inducible or worsening wall motion abnormality. Peak WMSI was used to reflect the extent of dysfunction (ischaemia or scar), and DeltaWMSI was indicative of extent of ischaemia. TAC was assessed at rest by simultaneous radial applanation tonometry and pulsed wave Doppler in all patients. RESULTS: Ischaemia was identified by stress echocardiography in 65 patients (25%). TAC was similar in the groups with negative and positive echocardiograms (1.08 (0.41) v 1.17 (0.51) ml/mm Hg, not significant). However, the extent of dysfunction was associated with TAC independently of age, blood pressure, risk factors, and use of a beta blocker. Moreover, the extent of ischaemia was determined by TAC, risk factors, and use of a beta blocker. CONCLUSION: While traditional cardiovascular risk factors are strong predictors of ischaemia on stress echocardiography, TAC is an independent predictor of the extent of ischaemia.

Relation of arterial stiffness to diastolic dysfunction in hypertensive heart disease.

OBJECTIVES: To examine the relation of arterial compliance to diastolic dysfunction in hypertensive patients with suspected diastolic heart failure (HF). PATIENTS: 70 medically treated hypertensive patients with exertional dyspnoea (40 women, mean (SD) age 58 (8) years) and 15 normotensive controls. MAIN OUTCOME MEASURES: Mitral annular early diastolic velocity with tissue Doppler imaging and flow propagation velocity were used as linear measures of diastolic function. Arterial compliance was determined by the pulse pressure method. RESULTS: According to conventional Doppler echocardiography of transmitral and pulmonary venous flow, diastolic function was classified as normal in 33 patients and abnormal in 37 patients. Of those with diastolic dysfunction, 28 had mild (impaired relaxation) and nine had advanced (pseudonormal filling) dysfunction. Arterial compliance was highest in controls (mean (SD) 1.32 (0.58) ml/mm Hg) and became progressively lower in patients with hypertension and normal function (1.04 (0.37) ml/mm Hg), impaired relaxation (0.89 (0.42) ml/mm Hg), and pseudonormal filling (0.80 (0.45) ml/mm Hg, p = 0.011). In patients with diastolic dysfunction, arterial compliance was inversely related to age (p = 0.02), blood pressure (p < 0.001), and estimated filling pressures (p < 0.01) and directly related to diastolic function (p < 0.01). After adjustment for age, sex, body size, blood pressure, and ventricular hypertrophy, arterial compliance was independently predictive of diastolic dysfunction. CONCLUSIONS: In hypertensive patients with exertional dyspnoea, progressively abnormal diastolic function is associated with reduced arterial compliance. Arterial compliance is an independent predictor of diastolic dysfunction in patients with hypertensive heart disease and should be considered a potential target for intervention in diastolic HF.

Pulse pressure vs. total arterial compliance as a marker of arterial health.

BACKGROUND: Brachial pulse pressure (BPP) is a predictor of outcome in epidemiologic studies, but brachial and aortic pulse pressure (AoPP) may not correspond and both are influenced by multiple parameters including arterial properties and cardiac output. We sought to what extent pulse pressure (PP) measurements reflected direct measurement of arterial properties, assessed as total arterial compliance (TAC). METHODS: We studied 123 patients (76 men; age 55 +/- 11); 31 normal controls, 46 patients with coronary artery disease and 46 patients with hypertension. PP was determined from brachial cuff pressure and TAC was measured by simultaneous radial applanation tonometry and pulsed wave Doppler of the LV outflow. AoPP was calculated using a transfer function from the radial waveform. RESULTS: There was a significant difference between BPP and AoPP (57 +/- 16 vs. 45 +/- 14; P < 0.0001), although TAC correlated with BPP (r = -0.72; P = 0.01) and AoPP (r = -0.66; P = 0.01). In a multiple linear regression, the difference between BPP and AoPP was predicted by cardiac output (CO) (P = 0.002) and gender (P = 0.03). Bland-Altman analysis showed the best correspondence between BPP and AoPP in the middle tertile (CO 4.7 to 5.7 L min(-1)) with less correlation in the low and high tertiles. The same analysis by gender showed a higher difference in women than men (14 +/- 6 vs. 10 +/- 5; P < 0.0001). The difference between BPP and AoPP showed the best correlation in the control group and the worst in the hypertension group. CONCLUSION: BPP correlates with TAC in men with normal cardiac function. However, in women, in patients at the low and high extremes of function, and in patients with preclinical and overt cardiovascular disease, there appears to be incremental value in measuring TAC.

Ultrafiltration improves aortic compliance in haemodialysis patients.

An elevated pulse pressure leads to an increased pulsatile cardiac load, and results from arterial stiffening. The aim of our study was to test whether a reduction in volume overload by ultrafiltration (UF) during haemodialysis (HD) leads to an improvement of aortic compliance. In 18 patients, aortic compliance was estimated noninvasively before and after HD with UF using a pulse pressure method based on the Windkessel model. This technique has not been applied before in a dialysis population, and combines carotid pulse contour analysis by applanation tonometry with aortic outflow measurements by Doppler echocardiography. The median UF volume was 2450 ml (range 1000-4000 ml). The aortic outflow volume after HD (39 ml; 32-53 ml) was lower (P=0.01) than before (46 ml; 29-60 ml). Carotid pulse pressure after HD (42 mmHg; 25-85 mmHg) was lower (P=0.01) than before (46 mmHg; 35-93 mmHg). Carotid augmentation index after HD (22%; 3-30%) was lower (P=0.001) than before (31%; 7-53%). Carotid-femoral pulse wave velocity was not different after HD (8.7 m/s; 5.6-28.9 m/s vs 7.7 m/s; 4.7-36.8 m/s). Aortic compliance after HD (1.10 ml/mmHg; 0.60-2.43 ml/mmHg) was higher (P=0.02) than before (1.05 ml/mmHg; 0.45-1.69 ml/mmHg). The increase in aortic stiffness in HD patients is partly caused by a reversible reduction of aortic compliance due to volume expansion. Volume withdrawal by HD moves the arterial wall characteristics back to a more favourable position on the nonlinear pressure-volume curve, reflected in a concomitant decrease in arterial pressure and improved aortic compliance.

Coronary circulation and interventional cardiology.

Cardiovascular disease has long been the leading cause of death in developed countries and it is rapidly becoming the number one killer in developing countries. Sudden heart attacks remain the primary cause of death in the United States: over 1.4 million attacks are suffered every year, more than half of which prove fatal. Interventional Cardiology is aimed to alleviate symptoms of cardiac pains and poor coronary circulation, and reduce the risk of death and nonfatal myocardial infarction. Our understanding of the coronary circulation has improved several folds due to the introduction of advance technologies. Yet, the microcirculatory flow needs future investigation.

Late incomplete lesion coverage following Cypher stent deployment for diffuse right coronary artery stenosis.

The availability of the only drug eluting stent currently approved in the USA has been limited, so that operators often resort to the deployment of multiple undersized stents and post-stenting high pressure inflations with larger balloons to achieve optimal lesion coverage and stent expansion. A case of stent fracture following percutaneous coronary intervention in which this strategy was used is reported.

Sonotherapy, antirestenotic therapeutic ultrasound in coronary arteries: the first clinical experience.

We studied the safety and feasibility of intracoronary sonotherapy (IST) and its effect on the coronary vessel at 6 months. Thirty-seven patients with stable or unstable angina were included (40 lesions). The indication was de novo lesion (n = 26), restenosis (n = 2), in-stent restenosis (n = 11), and a total occlusion of a venous bypass graft. After successful angioplasty, IST was performed using a 5 Fr catheter with three serial ultrasound transducers operating at 1 MHz. IST was successfully performed in 36 lesions (success rate, 90%). IST exposure time per lesion was 718 +/- 127 sec. During hospital stay, one patient died due to a bleeding complication. At 6-month follow-up, one patient experienced acute myocardial infarction, eight patients underwent repeat PTCA. No patient underwent CABG. Late lumen loss was 1.05 +/- 0.70 mm with a restenosis rate of 25%. IVUS analysis revealed a neointima burden of 25% +/- 11%. IST can be applied safely and with high acute procedural success. Sonotherapy-related major adverse events were not observed. Late lumen loss and neointimal growth were similar to conventional PTCA approaches. These results justify the initiation of randomized clinical efficacy studies.