Related Experiment Video

Updated: Jul 8, 2026

A Novel Rescue Technique for Difficult Intubation and Difficult Ventilation
04:46

A Novel Rescue Technique for Difficult Intubation and Difficult Ventilation

Published on: January 17, 2011

Evaluation of cuffed tracheal tube size predicted using the Khine formula in children

Caroline Duracher1, Emmanuelle Schmautz, Claire Martinon

  • 1Département d'Anesthésie Réanimation Chirurgicale et SAMU de Paris, Université Rene Descartes Paris, Paris Cedex, France.

Paediatric Anaesthesia
|January 11, 2008
PubMed

Insights

The Khine formula often suggests incorrect cuffed endotracheal tube (CET) sizes for children. A modified formula, [age/4 + 3.5], is recommended to better predict optimal CET size and reduce tracheal damage risks.

Area of Science:

  • Pediatric Anesthesiology
  • Airway Management
  • Medical Device Sizing

Background:

  • Correct cuffed endotracheal tube (CET) sizing is crucial for preventing postintubation tracheal damage in children.
  • Existing formulas, like the Khine formula, are used to predict appropriate CET sizes.
  • This study aimed to evaluate the accuracy of the Khine formula in pediatric patients.

Purpose of the Study:

  • To compare the actual cuffed endotracheal tube (CET) sizes used in children with those predicted by the Khine formula.
  • To identify discrepancies in CET sizing and assess potential risks.
  • To propose an improved formula for predicting optimal CET size in pediatric patients.

Main Methods:

  • Prospective study involving 204 children aged 1 day to 15 years.
  • Cuffed endotracheal tube (CET) size selection was at the anesthesiologist's discretion.
  • Comparison of pre- and post-cuff inflation leaks at 20 cmH2O, alongside demographic data and side effects.

Main Results:

  • Only 21% of chosen cuffed endotracheal tubes (CETs) matched the Khine formula predictions.
  • A significant majority (72%) of selected CETs were oversized, while 7% were undersized.
  • Minor postoperative complications occurred in 2.9% of patients, with some initial tube sizes being adjusted.

Conclusions:

  • The Khine formula tends to underestimate the optimal cuffed endotracheal tube (CET) size by approximately 0.5 mm.
  • A revised formula, internal diameter of CET = [age/4 + 3.5] for children over 1 year, is recommended.
  • This adjusted formula may be safely applied without increasing complication rates, supported by leak and reintubation data.
Abstract

More Related Videos

The Rigid Tube as an Alternative in Controlling the Problematic Airway08:26

The Rigid Tube as an Alternative in Controlling the Problematic Airway

Published on: June 6, 2020

Related Concept Videos

Tracheostomy: Procedure and Tubes01:28

Tracheostomy: Procedure and Tubes

A tracheostomy is a surgical procedure that creates an artificial opening into the trachea, typically at the second or third cartilaginous ring level. This opening allows the insertion of a tracheostomy tube, which can replace an endotracheal tube, provide mechanical ventilation, bypass an upper airway obstruction, or remove accumulated tracheobronchial secretions.
Tracheostomy tubes can be made of semiflexible plastic (polyurethane or silicone), rigid plastic, or metal, and they come in...
Endotracheal Intubation I: Procedure01:15

Endotracheal Intubation I: Procedure

Endotracheal or ET intubation is a critical medical procedure used to secure a patient's airway, often in acute respiratory distress, apnea, upper airway obstruction, ineffective clearance of secretions, high risk for aspiration, or during general anesthesia.
The ET tube comprises various components, including a standard adaptor to attach a bag-valve-mask (BVM) or ventilator, a cuff, a pilot balloon, and radiopaque markings along its length to measure the insertion distance. The tube sizes...
Oxygen Delivering System II: Venturi Mask and Transtracheal Oxygen01:16

Oxygen Delivering System II: Venturi Mask and Transtracheal Oxygen

Oxygen therapy is a pivotal aspect of medical care, particularly for patients with respiratory ailments. Two prominent oxygen-delivering systems include the Venturi mask and the transtracheal oxygen catheter.
Venturi Mask
The Venturi mask, named after the Venturi effect, is designed to deliver precise oxygen concentrations. It consists of a large tube with an oxygen inlet that narrows down, causing a pressure drop that pulls air in through adjustable side ports. The mask is a lightweight,...
Oxygen Delivering System III: Tracheostomy and T-piece01:23

Oxygen Delivering System III: Tracheostomy and T-piece

Oxygen delivery is critical in clinical care, especially for patients with respiratory disorders or those undergoing surgical procedures. Various systems, such as tracheostomy and the T-piece, deliver oxygen to the lungs, ensuring adequate arterial oxygenation.
Tracheostomy
A tracheostomy is a surgically created opening (stoma) in the anterior part of the trachea. It is used to establish a patient airway, bypass an upper airway obstruction, simplify the removal of secretions, permit long-term...
Tracheostomy Care II: Procedure01:25

Tracheostomy Care II: Procedure

Tracheostomy care is an essential nursing skill that involves cleaning and maintaining a tracheostomy tube to prevent infection and other complications. Here's a step-by-step guide explaining each procedure with its rationale. Note that disposable gloves are to be worn at all times and changed as often as needed to maintain a sterile work environment, and to protect both patient and healthcare worker.
Step 1: Perform hand hygiene, and put on personal protective equipment: gown, gloves, mask and...
Tracheostomy Care I: Pre-procedural Steps01:16

Tracheostomy Care I: Pre-procedural Steps

A tracheostomy is a surgical technique that involves making an incision in the neck to provide access to the trachea. It is frequently used in medical conditions such as airway obstruction and prolonged mechanical ventilation. Effective nursing management is crucial for the long-term success of a tracheostomy.
Required Equipment
The equipment necessary for tracheostomy care includes: