nonpolar covalent bond. (physical chemistry). A bond in which a pair of electrons is distributed or shared equally between two atoms. 1  Facebook.2  Twitter.onpolar covalent bond. (physical chemistry). A bond in which a pair of electrons is distributed or shared equally between two atoms. 1  Facebook.
When is a barrel chest a sign of a disease process? Chronic obstructive pulmonary disease (COPD) is the most common instance in which a barrel chest will occur. In these cases, itâs a sign of the lungs being over-expanded. This is caused by the loss of elasticity and results in the person having hyper-inflated lungs.
Lung infections are the most common cause of acute exacerbations. These infections can be viral or bacterial. Some specific viruses that cause COPD exacerbations are influenza, rhinovirus or adenovirus. Recent evidence suggests exacerbations of COPD are often caused by certain kinds of bacteria. These are known as mycoplasma and chlamydia.