A new formula for estimating endotracheal tube insertion depth in neonates

Endotracheal tube extubation is a critical procedure in weaning patients from mechanical ventilation. It involves physically removing the oral or nasal endotracheal (ET) tube, marking the final step in liberating a patient from ventilatory support.
Procedure
Extubation removes the endotracheal tube (ETT) from the patient on mechanical ventilation. It requires a well-coordinated, multidisciplinary approach involving physicians, nurses, respiratory therapists, and other healthcare professionals....

A chemical formula presents information about the proportions of atoms constituting a particular chemical compound or molecule, mainly using symbols of elements and numbers. At times other symbols, such as dashes, parentheses, brackets, commas, plus, and minus signs, are also used. A chemical formula can be one of three types – molecular, empirical, and structural.

The elemental makeup of a compound defines its chemical identity, and chemical formulas are the most concise way of representing this elemental makeup. When a compound’s formula is unknown, measuring the mass of its constituent elements is often the first step in determining the formula experimentally.

An element composed of atoms that readily lose electrons (a metal) can react with an element composed of atoms that readily gain electrons (a nonmetal) to produce ions through complete electron transfer. The compound formed by this transfer is stabilized by the electrostatic attractions (ionic bonds) between the oppositely charged ions.

Molecular compounds or covalent compounds result when atoms share electrons to form covalent bonds. Since there is no electron transfer, molecular compounds do not contain ions; instead, they consist of discrete, neutral molecules. 

Formula Mass of Covalent Compounds