Browsing Tag

pulmonary

High Flow Nasal Cannula (HFNC)

High flow nasal cannula (HFNC) systems allow us to deliver warm, humidified oxygen at flow rates as high as 60 liters/min through small, pliable nasal prongs. The cannula itself is fit into the nares and stabilized with a head strap. Two…

What Is Pleurodesis?

Pleurodesis is a procedure aimed to obliterate the intrapleural space and is performed for recurrent malignant/non-malignant effusions and recurrent pneumothorax. 

Hypoxic Pulmonary Vasoconstriction (HPV)

Hypoxic pulmonary vasoconstriction (HPV) is an intrinsic property of the lung where vascular smooth muscle will constrict pulmonary circulation in response to areas of hypoxia. In other words, if an alveolus is not being well ventilated…

PaCO2 Equation

I've previously written about the alveolar gas equation and oxygen delivery equation, both of which deal with the physiologic process of oxygenation. Now I want to discuss the important relationship between alveolar ventilation (VA), carbon…

Alveolar Gas Equation

I previously wrote about the oxygen delivery equation mathematically describing a vital concept in physiology. Now I want to discuss another critically important formula in acute care medicine - the alveolar gas equation.

Oxygen Delivery Equation

One of the most important equations in physiology describes the delivery of oxygen to tissues in the body. Naturally, this would be related to the cardiac output (CO) and overall oxygen content in the blood (CaO2). As I wrote about in a…

Ventilation Modes Change Cardiac Output

Take a deep breath. Your diaphragm is contracting downward increasing your intrathoracic volume with a resulting decrease in pressure according to Boyle's Law. This new pressure is less than that of atmospheric pressure ("negative…

Why Does Oxygen Therapy Cause Hypercapnia In COPD?

Ask young physicians why patients with chronic obstructive pulmonary disease (COPD) tend to retain CO2 (hypercapnia) when given oxygen therapy. I bet the majority will claim that supplemental oxygen depresses one's "hypoxic drive" to…

Treating Emphysema with Gene Therapy

Cystic fibrosis and α1-antitrypsin deficiency are the two most common inherited lung diseases, and both of them happen to be caused by a known, single gene mutation. A study conducted at Boston University's School of Medicine and recently…