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MATHEMATICS OF PRONE POSITION AND IMPLICATION IN ARDS

"It appears that pulmonary mechanics is evolutionary designed and optimised for prone position, which is the normal posture in quadrupeds"   Prone position is used in operation rooms for a long time for surgical procedures on dorsal aspect of body. It has been acknowledged that respiratory and hemodynamic instability may result because of compression of chest and abdomen in prone position, which may be relieved by supporting upper chest and pelvis with padding, to facilitate free movement of anterior abdominal wall.   Beneficial effect of prone position in respiratory mechanics was first proposed by Bryan in 1974. Bryan studied the effect of sedation and paralysis on diaphragm, and suggested that prone position improve dorsal lung expansion and oxygenation 1 . Few years later  Piehl and Douglas separately reported that prone position dramatically improved oxygenation in ARDS patients 2,3 .   But, it had to take one more decade, to understand the mechanism of prone position in
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THE CLIMAX OF WAR AGAINST BACTERIAL RESISTANCE- VICTORY VERSUS TRUCE

“The time may come when penicillin can be bought by anyone in the shops. Then there is the danger that the ignorant man may easily under dose himself and by exposing his microbes to non-lethal quantities of the drug make them resistant. Here is a hypothetical illustration. Mr. X. has a sore throat. He buys some penicillin and gives himself, not enough to kill the streptococci but enough to educate them to resist penicillin. He then infects his wife. Mrs. X gets pneumonia and is treated with penicillin. As the streptococci are now resistant to penicillin the treatment fails. Mrs. X dies. Who is primarily responsible for Mrs. X’s death?” Above statement has been borrowed from the Alexander Fleming’s noble lecture delivered on December 11, 1945. [1] Fleming’s serendipitous discovery of penicillin and its therapeutic potential in treating bacterial infection was a boon to mankind. However, shortly thereafter resistance to penicillin as well other discoverd antibiotics was observed. Scie

THE ACT OF PLAYING GOD- EXTENDING LIFE VS PROLONGING DEATH

“Ethics is knowing the difference between what you have a right to do, and what is right to do.”  -  Potter Stewart, Associate Justice, United States Supreme Court, 1958-1981 . Before the evolution of modern medicine, death had been a well-accepted inevitability of life, wished to happen at home surrounded by family members. This inescapable truth had become an integral component of every religion, culture and society with defined rites and rituals. With the advent of cardiopulmonary resuscitation and organ support technologies in the second half of last century, this integrated approach to end of life started receding towards denial, altering the trajectory of the process of dying. [2] Now ordinary people want and demand everything to be done to prolong the life of their loved ones, as it gives a virtual satisfaction to them and answer to others. Chest compression, defibrillation, escalating vasopressors, mechanical ventilation, dialysis, artificial nutrition in the loneliness of i

MECHANICAL VENTILATION: IN SEARCH OF TRUE SURROGATE TO PREVENT VILI

  From respirator lung to ventilator induced lung injury, we have travelled a long distance from the concept of barotrauma-volutrauma to stress-strain. Stress is defined as equal and opposite force developed in a material, when exposed to external force, while strain is change in the area or volume from baseline, brought about in this process. Stress-strain relationship is a function of material property, solid, viscous or viscoelastic. Current strategy of mechanical ventilation as endorsed by ARDS net, is limiting the tidal volume and plateau airway pressure to 6 ml per kg of predicted body weight and 30 cmH 2 O. Baby lung volume in ARDS is variable with severity of disease, worse is the ARDS, smaller is the baby lung. As baby lung has normal compliance, setting tidal volume according to predicted body weight, may be safe to unsafe depending upon baby lung volume. Lung behaves like viscoelastic material, which makes pulmonary mechanics time dependent. For a constant tid

Spirit to Autoantibodies- Journey of Limbic Disorders from Philosophy to Affective Neuroscience

“Education is a progressive discovery of our own ignorance” Will Durant Since the inception of human society, people have been intrigued about the mystery of human behavior and emotions. Scholars came up with different explanations based on existing belief system, knowledge and evidences. Greek philosopher Aristotle believed heart as center of intelligence and emotions. Few centuries later, another Greek philosopher Galen explained that animal spirit originates in the heart and travels via the circulatory system to brain. Galen described his assumptions based on dissection of corpse, and further elaborated that cerebral ventricles are the epicenter of reasons and emotions. In the medieval period, accurate reproduction of images by artists like Da Vinci, Michelangelo and Rembrandt as well as rapid dissemination of knowledge by printing press, led to better understanding of human neuroanatomy and neurophysiology. As a result, by the end of eighteenth century, knowledge of huma