Tidal Volume Calculator - Endotracheal Tube (ETT) Depth

Determines the target tidal volume by height and depth of ETT placement.

The target tidal volume is obtained based on ideal body weight (which takes into consideration patient height and gender) to provide guidance on initial ventilator setting.

This calculator determines the optimal endotracheal tube placement (based on patient height) to avoid right mainstem intubation, hypoxemia, and pneumothorax (when ETT is placed too deeply) or injury to vocal cords or accidental extubation (when ETT placed too shallowly).

• ETT depth from front teeth (cm) (Chula formula) = 0.1 x Height in cm + 4
• Target tidal volume ranges from 6 to 8 mL/kg IBW

Where:

• IBW male = 50kg + 2.3 x (Height in inches – 60)
• IBW female = 45.4kg + 2.3 x (Height in inches – 60)

Gender
Height
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Steps on how to print your input & results:

2. Then you can click on the Print button to open a PDF in a separate window with the inputs and results. You can further save the PDF or print it.

Please note that once you have closed the PDF you need to click on the Calculate button before you try opening it again, otherwise the input and/or results may not appear in the pdf.

Estimating ideal ETT position

This calculator determines the optimal endotracheal tube placement (based on patient height) to avoid right mainstem intubation, hypoxemia, and pneumothorax (when ETT is placed too deeply) or injury to vocal cords or accidental extubation (when ETT placed too shallowly).

`ETT depth from front teeth (cm) (Chula formula) = 0.1 x Height in cm + 4`

Whilst the height-based calculation does not exclude the need for chest x-ray, auscultation or ultrasound in determining ETT depth, it can assist with getting the ETT into a safe position from the start.

In cases with critical hypoxemia, delivering the ETT into the mid-trachea immediately may prevent desaturation.

In the original study, the Chula formula was tested on 100 patients of equal genders, who underwent general anesthesia with orotracheal intubation

With the help of a fiberoptic bronchoscope (inserted into the ETT after intubation) the distance from the tip of ETT to the carina and the distance from the upper border of the cuff of ETT to the vocal cords were measured.

Target tidal volume

Tidal volume is the measure of the amount of air inhaled during a normal breath. Safe tidal volumes can be determined based on patient’s height and gender and the rule of thumb, when lung-protective ventilation is required, is setting the tidal volume at 6-8 mL/kg ideal body weight.

Target tidal volume ranges from 6 to 8 mL/kg IBW, where:

• `IBW male = 50kg + 2.3 x (Height in inches – 60)`
• `IBW female = 45.5kg + 2.3 x (Height in inches – 60)`

Traditional pre-set tidal volumes higher than 10 ml/kg have been proved to be associated with increased risk of pulmonary barotrauma, decreased venous return and reduced cardiac output.

In patients with acute lung disease, recent studies have shown correlation between use of lower tidal volume and decreased mortality.

Tidal volumes between 6 and 6 mL/kg IBW are advised in ventilating patients with acute lung disease such as:

References

Techanivate A, Kumwilaisak K, Samranrean S. Estimation of the proper length of orotracheal intubation by Chula formula. J Med Assoc Thai. 2005; 88(12):1838-46.

Warner MA, Patel B. Chapter 48 - Mechanical Ventilation; Benumof and Hagberg's Airway Management (Third Edition) 2013, Pages 981-997.e3.

Fuller BM, Ferguson IT, Mohr NM, Drewry AM, Palmer C, Wessman BT, Ablordeppey E, Keeperman J, Stephens RJ, Briscoe CC, Kolomiets AA, Hotchkiss RS, Kollef MH. Lung-Protective Ventilation Initiated in the Emergency Department (LOV-ED): A Quasi-Experimental, Before-After Trial. Ann Emerg Med. 2017; 70(3):406-418.e4.

Specialty: Pulmonology

System: Respiratory

Article By: Denise Nedea

Published On: May 11, 2020 · 12:00 AM

Last Checked: May 11, 2020

Next Review: May 11, 2020