ObjectiveAdequacy of cardiopulmonary resuscitation relies on compression of the thoracic cage to produce changes in intra-thoracic pressures sufficient to generate a pressure gradient. In order to evaluate the efficacy of cardiopulmonary resuscitation in morbid obesity, it is first necessary to determine the depth of thoracic subcutaneous adipose tissue (SAT) and to correlate this with body mass index (BMI).ResultsComputerised-tomography images of the thorax of 55 patients with a diagnosis of obesity or morbid obesity (mean BMI 45.95 kg/m2) were evaluated to determine the depth of SAT at the level at which chest compressions would be applied by a trained rescuer, and correlated with BMI. Mean anterior SAT was 36.53 mm, and mean posterior SAT was 50.73 mm. There was a significant correlation between BMI and anterior and posterior SAT for males (p < 0.05 for both), and females (p < 0.05 for both). The slope of the functions was considered sufficiently close to allow combining the data. This also showed a significant correlation between SAT and BMI (p < 0.01 for both). Both anterior and posterior SAT is correlated with BMI. This data allows development of a model to explore the efficacy of chest compressions in morbid obesity.Electronic supplementary materialThe online version of this article (10.1186/s13104-017-2918-9) contains supplementary material, which is available to authorized users.

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Adequate cardiopulmonary resuscitation is an important predictor of survival, however, obesity provides a significant physical barrier to thoracic compressions. This study explores the effect of morbid obesity on compression adequacy. We performed a prospective randomised controlled crossover study, assessing the adequacy of thoracic compressions on a manikin modified to emulate a morbidly obese patient. Participants recruited from critical care departments were randomised to perform continuous compressions for two minutes on each manikin. Accelerometers were used to measure thoracic wall movement. The primary endpoint was a composite measure of compression adequacy (rate, depth and recoil). Secondary endpoints were the individual components of the composite outcome and measures of perceived effectiveness, fatigue, and pain. One hundred and one participants were recruited. There was a significant difference between the obese and control groups in the composite endpoint (4% versus 30%, P <0.001), as well as the individual components of adequacy (P <0.01 for all). Quartile data showed significant deterioration in adequacy of depth and recoil in both groups, and this occurred significantly earlier in the obese group (P ≤0.001). Participants' perception of effectiveness was significantly lower (P ≤0.001) in the obese group, and levels of fatigue (P ≤0.001) and pain (P ≤0.001) significantly higher. Morbid obesity impairs the adequacy of thoracic compressions for trained rescuers in a simulation-based model. Participants were not fully aware of how ineffective compressions were. There is evidence of earlier fatigue further reducing effectiveness. These findings have significant implications for the training of rescuers in a clinically relevant population and the planning of future research.

CorrespondenceAttitudes towards the safety of using uni-polar diathermy in association with the presence of a space blanket were also investigated; 88% of teaching hospital anaesthetists felt the combination was safe, but this was true of only 52% of district general hospital anaesthetists. This uncertainty clearly influences the intra-operative use of space blankets.Modern space blankets are made of metallised plastic sheeting, are nonconductive and therefore provide electrical as well as thermal insulation. They can be easily applied in the anaesthetic room as part of routine preparation of the patient for major surgery and a 'window' cut to allow surgical access.This survey shows that the possibility of reducing heat loss by the intra-operative use of a space blanket needs to be better appreciated, especially by those working in district general hospitals. Even in these cost-conscious days, 95p (current price) cannot be considered an excessive price to pay for such clear advantages. We would therefore like to endorse the early use of space blankets in operating theatres to help prevent heat loss and thereby minimise the early postoperative sequelae resulting from hypothermia.