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Radiation exposure during complex endovascular repair of the aorta

Authors:
Aim: There are no reported studies in the literature describing ultrasound
guided inltration (USGI) of local anaesthetic(LA) in endovascular aneu-
rysm repair(EVAR) in patients in whom general/regional anaesthesia(GA/
RA) is contra-indicated. We report for the rst time, a new technique of LA
inltration for EVAR and investigate its acceptability to patients using
surrogate markers of peri-operative pain (POP), anxiety(POA) and patient
satisfaction(PS).
Methods: All patients unsuitable for GA/RA between October 2013 and
September 2014 under a single consultant Vascular Surgeon at a District
General Hospital were included. USGI was used to block the appropriate
nerve territories and tumesce the common femoral artery in an attempt to
provide an effective LA. Visual analogue scales were used to assess the
aforementioned parameters immediately following the procedure prior to
leaving theatre.
Results: 5 patients were unable to have GA/RA and were used in this
feasibility study; 3were elective and 2emergency, 3had bilateral and 2had
unilateral USGI. The median POP, POA and PS were 2.98/10 [0.4-5.3], 28.5%
[0-73] and 92.2%[73-100] respectively. The procedure had a 86.4% [48-100]
friends and family recommendation score.
Conclusion: This feasibility study demonstrates an effective local anaes-
thesia for EVAR can be achieved using USGI using the surrogate markers
POP, POA and PS.
0705: HOW CAN SURGEONS MONITOR THEMSELVES BETTER:
VALIDATING PERFORMANCE OF CUSUM (SPRT) REAL-TIME
MONITORING METHODS USING ANONYMISED UK NATIONAL
VASCULAR DATABASE
C. Wou
*
, F. Durrant, A. Jibawi. Ashford and St Peter's Hospitals NHS
Foundation Trust, UK
Aim: Traditional audits are unable to provide short feedback loops to
quickly identify underperforming surgical units. We aim to assess reli-
ability and accuracy of continuous monitoring of vascular outcomes us-
ing CUSUM.
Methods: Cumulative mortality, funnel plot and CUSUM (SPRT) were
applied to the National Vascular Database (NVD) and performances
compared. In-hospital mortality for 140 centres (1995-2011) following
elective abdominal aneurysm repair were compared. Datawas adjus ted for
case-mix. Doubling of odds ratios (OR) were considered a proxy for sig-
nicant deviation from the accepted surgical failure rate from national
mortality rates (p). Control limits were approximated using simulation,
Markov chain and fractional polynomial techniques. Average run length
was used as a performance measure.
Results: Compared to audit, CUSUM has signicant sensitivity to a unit's
outlier status, with an average of 0.89 alerts (no outlier status) to 23
alerts (outlier status). For best CUSUM performance, values of OR¼3
and p¼3 correlated with CUSUM sensitivity of 80%, specicity of
80% and positive predictive value of 78%. Fractional polynomial tech-
nique and CUSUM simulations correlated well to real-time NVD data
analysis.
Conclusion: CUSUM techniques can be optimised to detect outliers in real-
time, and adjusted for case-mix to ensure a 'level playing eld' for all units.
0725: IS IT POSSIBLE TO QUANTIFY THE CHANGE IN SERVICE DEMAND
FOR AORTIC SURGERY FOLLOWING THE CENTRALISATION PROCESS: AN
NVD-BASED PREDICTIVE MODEL
F. Durrant
*
, C. Wou, A. Jibawi. ASPH, Chertsey, UK
Aim: The centralisation of aortic aneurysm surgery centres has created
challenges through limited availability of key resources. This study aims to
compare changes in aortic surgery workload between 2008-2010 and
2010-2012 using data from the National Vascular Database (NVD).
Methods: Data from the NVD for each Trust was compared between two
time frames. Three models were used to provide predictive model: ANOVA
analysis, A Wilcoxon Rank-Sum Test and regression coefcient estimation.
Multiple regression analysis was used to build a predictive model to esti-
mate changes in workload. Actual vs. predicted workload was tested, and
standardized residual values analysed.
Results: In the second period, 1117 more open and 3916 more EVAR pro-
cedures were performed. The average of submitted procedures rose by 52
cases in the second period. Average mortality rate fell by 5% (open) and
0.1% (EVAR). Wilcoxon Rank-Sum Test demonstrated a signicant increase
(p<0.005) in the overall workload for all relevant Trusts.
Based on this analysis, a prediction equation was devised:
(workload
2012
¼A+B*workload.
2010
)
where A ¼34.75 and B ¼1.21.
Conclusion: For each centre, workload increased by 1.21 times that of pre-
centralisation. Vascular service planning should consider this and match
capacity (theatre sessions, secretarial support, and staff) accordingly.
0745: EVIDENCE BASED MANAGEMENT OF CRANIOFACIAL
HYPERHIDROSIS: A SYSTEMATIC REVIEW
A. Quddus
*
, M. Robinson, R. Nicholas, D. Baker. Royal Free Hospital, UK
Aim: Primary Craniofacial Hyperhidrosis (CH) can adversely impact
quality of life. No comprehensive review of management exists. Here, we
review the evidence to guide CH management.
Methods: Two independent reviewers performed a systematic review
using PRISMA guidelines. MEDLINE and EMBASE were searched (1966-
2014). Articles containing MeSH terms Hyperhidrosis,Head,Neck,
and synonymous text words. Inclusion criteria were experimental and
observational studies addressing CH treatment.
Results: Of 832 references, 26 met inclusion criteria. Twenty-two studies
evaluated T2 sympathetic ablation (level III evidence). Outcome mea-
sures were subjective and follow-up was short (18/24 <2yrs). Reported
efcacy was high (70-100%), recurrence rates were low (0-7.8%), and
complications transient. 10-89% experienced troubling compensatory
sweating. One RCT and one observational study evaluated Botox. Both
employed objective outcome measures, with similar ndings. 100% ef-
cacy lasted a median of 5-6 months. The main side effect was frontalis
muscle inhibitio n. Two studies evaluated Anticholinergic therapy-
topical glycopyrrolate (efcacy 96%) and minimal oxybutynin (efcacy
60%).
Conclusion: There are few quality studies evaluating CH treatment clini-
cally. Based on current available evidence, we recommend topical glyco-
pyrrolate and intradermal Botox as rst line therapies due to their efcacy
and safety. T2 sympathectomy should be reserved for patients refractory
to rst line therapy.
0760: RADIATION EXPOSURE DURING COMPLEX ENDOVASCULAR
REPAIR OF THE AORTA
S. Kelly
*
, M. Albayati, D. Gallagher, R. Dourado, A. Patel, P. Saha, A. Bajwa, T.
El-Sayed, R. Salter, S. Abisi, T. Carrell, B. Modarai. King's College London, UK
Aim: To compare radiation dose to the operating team for complex
(branched and fenestrated) endovascular aortic repairs with safe limits set
by the International Consultation on Radiological Protection (ICRP) and to
determine predictive factors of radiation exposure.
Methods: Elective branched and fenestrated procedures were analysed
prospectively in a hybrid-operating theatre using cumulative electronic
dosimeters. Radiation dose to the body, both over and under lead gar-
ments, as well as to the head, were recorded for the main-operator and
assistant. Mann-Whitney U, univariate and multivariate linear regression
tests were employed.
Results: Of 17 cases studied, over-lead body dose (IQR) was signicantly
higher for the main operator compared with the assistant, 80
m
Sv (37-163)
vs 32
m
Sv (6-48); p¼0.003, as was the case for head dose, 54
m
Sv (24-130) vs
15
m
Sv (7-43); p¼0.022. Operator height, total digital subtraction angiog-
raphy (DSA) acquisition time and acquisition time in left anterior-oblique
(LAO) and cranial positions, p<0.05, independently predicted main oper-
ator head dose.
Conclusion: Radiation exposure in the hybrid-operating environment
compares favourably with doses previously measured in the interventional
radiology-suite. However, every effort must be made to minimise DSA
runs, as well as time spent in LAO and cranial positioning as adverse sto-
chastic effects may occur at any dose.
Abstracts / International Journal of Surgery 23 (2015) S15eS134S132
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