Pathophysiological mechanism of post-lobectomy air leaks.

Background: Air leak post-lobectomy continues to remain a significant clinical problem, with upper lobectomy associated with higher air leak rates. This paper investigated the pathophysiological role of pleural stress in the development of post-lobectomy air leak.

Methods: Preoperative characteristics and postoperative data from 367 consecutive video assisted thoracic surgery (VATS) lobectomy resections from one centre were collected prospectively between January 2014 and March 2017.

Physiological rules for the heart, lungs and other pressure-based organs.

Background: The adherence of the heart to physical laws, such as Laplace's Law, may act as a measure of the organ's relative efficiency. Allometric relationships were investigated to assess the heart's efficiency concerning end-diastolic and end-systolic volumes, cardiac pressurization energy, cardiac output and mass.

Methods: Data to generate allometric relationships was obtained using a literature search, identifying heart and lung data across different mammalian and bird species.

Pleural pressure theory revisited: a role for capillary equilibrium.

Background: Theories elucidating pleural pressures should explain all observations including the equal and opposite recoil of the chest wall and lungs, the less than expected pleural hydrostatic gradient and its variation at lobar margins, why pleural pressures are negative and how pleural fluid circulation functions.

Methods: A theoretical model describing equilibrium between buoyancy, hydrostatic forces, and capillary forces is proposed. The capillary equilibrium model described depends on control of pleural fluid volume and protein content, powered by an active pleural pump.

Method of Hemorrhage Control From the Aorta After Repair of a Dissected Aortic Aneurysm.

Patients with Marfan syndrome and presenting with acute aortic dissection have fragile aorta, causing bleeding problems in the anastomosis between the graft and the aorta. Hemostatic impairment following circulatory arrest and prolonged cardiopulmonary bypass contribute to these problems. We describe a technique to control persistent bleeding from the anastomosis in the aortopulmonary recess using two kissing inflated balloons at the tip of two Foley catheters to tamponade the bleeding sites.

A biomechanical hypothesis for the pathophysiology of apical lung disease.

Objective: A hypothesis is presented suggesting that the pathogenesis of apical lung disease is due to progression of subclinical congenital apical bullae in people with low Body Mass Index (BMI), a combination present in 15% of the population, due to high pleural stress levels present in the antero-posteriorly flattened chests of these individuals.

Design: The hypothesis was tested for validity in two apical lung pathologies with widespread epidemiological literature, namely tuberculosis (TB) and primary spontaneous pneumothorax (PSP), assessing whether the hypothesis could identify high-risk populations, explain exceptional cases like apical lower lobe disease and confirm predictions.

Results: The biomechanical hypothesis can explain the high-risk factors of apical location, age, gender and low-BMI build, as well as the occurrence of disease in the apex of the lower lobe, in both TB and PSP patients.

Internal rib structure can be predicted using mathematical models: An anatomic study comparing the chest to a shell dome with application to understanding fractures.

The human rib cage resembles a masonry dome in shape. Masonry domes have a particular construction that mimics stress distribution. Rib cortical thickness and bone density were analyzed to determine whether the morphology of the rib cage is sufficiently similar to a shell dome for internal rib structure to be predicted mathematically.

A large pulmonary arteriovenous malformation causing cerebrovascular accidents.

The incidence of pulmonary arteriovenous malformations (PAVMs) is 2.5 in 100,000. 80% are associated with Osler-Weber-Rendu syndrome or hereditary haemorrhagic telangiectasia.

External rib structure can be predicted using mathematical models: An anatomical study with application to understanding fractures and intercostal muscle function.

As ribs adapt to stress like all bones, and the chest behaves as a pressure vessel, the effect of stress on the ribs can be determined by measuring rib height and thickness. Rib height and thickness (depth) were measured using CT scans of seven rib cages from anonymized cadavers. A Finite Element Analysis (FEA) model of a rib cage was constructed using a validated approach and used to calculate intramuscular forces as the vectors of both circumferential and axial chest wall forces at right angles to the ribs.

A novel method of personnel cooling in an operating theatre environment.

An optimized theatre environment, including personal temperature regulation, can help maintain concentration, extend work times and may improve surgical outcomes. However, devices, such as cooling vests, are bulky and may impair the surgeon's mobility. We describe the use of a low-cost, low-energy 'bladeless fan' as a personal cooling device.

Mechanism of sternotomy dehiscence.

Objectives: Biomechanical modelling of the forces acting on a median sternotomy can explain the mechanism of sternotomy dehiscence, leading to improved closure techniques.

Methods: Chest wall forces on 40 kPa coughing were measured using a novel finite element analysis (FEA) ellipsoid chest model, based on average measurements of eight adult male thoracic computerized tomography (CT) scans, with Pearson's correlation coefficient used to assess the anatomical accuracy. Another FEA model was constructed representing the barrel chest of chronic obstructive pulmonary disease (COPD) patients.

Is there a biomechanical cause for spontaneous pneumothorax?

Objectives: Primary spontaneous pneumothorax has long been explained as being without apparent cause. This paper deals with the effect of chest wall shape and explains how this may lead to the pathogenesis of primary spontaneous pneumothorax.

Methods: Rib cage measurements were taken from chest radiographs in 12 male pneumothorax patients and 12 age-matched controls.

Sternal wrapping: developments and results.

Background: Postoperative sternal wound complications are infrequent events that negatively affect recovery and may have serious consequences. Sternal wrapping, a technique of sternal care, has hemostatic properties without bone wax, and offers mechanical and microbiologic protection.

Methods: From February 1998 to December 2011, 258 patients in 2 Italian institutions underwent various cardiac surgery procedures with sternal wrapping in place, and were followed up for no less then 6 months.

Intrathoracic schwannoma with Horner syndrome.

Horner syndrome (HS) results from the interruption of the sympathetic pathway to the eye and face, and describes a collection of signs consisting of ipsilateral miosis, partial ptosis, anhidrosis and apparent enophthalmos. It is a clinical observation, and has a plethora of possible causes, ranging from the benign to the malignant. Involvement of the stellate ganglion on the sympathetic chain by malignant tumours of the lung is a well-recognised cause of HS.

Cardiopulmonary bypass line sternal wrapping: technical tips.

Cardiopulmonary bypass line sternal wrapping (SW) is a new approach to sternal care which avoids bone wax and offers mechanical protection and a shield from bacterial contamination, with beneficial effects on sternal healing. Since its introduction in February 2008, the technique has undergone some developments: it is possible to harvest internal thoracic arteries with SW in place and its haemostatic properties have improved.

Cardiopulmonary bypass line sternal wrapping for protection and haemostasis.

Sternal marrow haemostasis is often obtained with the application of bone wax, with potential side effects pertaining to sternal wound healing. We illustrate an alternative technique which also offers some protection to sternal edges. Two lengths of tubing from the discarded cardiopulmonary bypass (CPB) circuit are cut longitudinally on one side.

Early dialysis in acute kidney injury after cardiac surgery.

Acute kidney injury following cardiac surgery (AKICS) remains a frequent cause of major morbidity and mortality. The aim of this study was to examine the influence of timing of dialysis. A retrospective analysis of 3528 patients undergoing cardiac surgery between April 1995 and July 2006 was performed.

Empyema thoracis caused by a foreign body inhaled 30 years previously.

We present the case of a 73 year old Caucasian male who developed a left sided pneumonia and empyema secondary to a foreign body inhaled 30 years before. The foreign body, a bone fragment, was lodged at the bifurcation of the left main bronchus and could only be removed via bronchotomy. The patient experienced a swift recovery and was well at follow-up 6 months later.