Title : Sonic Endotracheal tube detector Name & Address M. Christopher, 7, Thendral nagar, Near Medical College Men's Hostel, Tirunelveli District, Tamil Nadu, India.

Preamble :

Identification of Endotracheal Tube is crucial during anaesthesia and emergency resuscitation during Cardio — respiratory arrest and in the management of road traffic accident victims and transfer of intubated patients on transport ventilator. Oesophageal opening is just below the tracheal opening and wrong intubation is possible.

Description of invention : Sonic Endotracheal tube detector is a device to identify to correct position of endotracheal tube during anaesthesia and emergency intubation during respiratory arrest and endotracheal tube slipping into oesophagus during anaesthesia and patient transfer to tertiary care centres. Accidental Oesophageal intubation has to be diagnosed within seconds to prevent irreversible brain damage and death.

If the ETT is in oesophagus only one phase of sound is heard and visualised as

(H)

During continuous monitoring of tracheal intubation the graph will be as

In oesophageal .intubation the graph will be as

Audio Visual sequence:

Audio sensor — ► Sound amplification — ► Signal converter *" Data accumulator * ^" Data processing *" Display in computer screen .

Salient features :

Instant audio visual display of breath sounds.. No need for calibration.

Life saving, Reliable, Less expensive device.

Principle :

Respiration has two phases inspiratory and expiratory. Ventilation through trachea will have two phases due to elastic recoil of lungs . Accidental wrong attempt to ventilate through oesophagus will have only one phase since stomach cannot recoil.

The phase of these sounds are sensed, amplified , converted in to signals , data accumulated, processed and displayed in computer screen as continuous graph.

The graph denotes time in X axis and amplitude of sound in Y axis. As the amplitude of sound increases there will be a upstroke. If there is sustained sound in the same amplitude the graph shows parallel line and down stroke as the sound fades

Graph of tracheal intubation

It has a uptroke and sustained parallel line which is the inspiratory phase, a pause between inspiration and expiration which is marked as a depression and the expiratory phase due to elastic recoil of lungs, takes the graph again to a parallel line and soon after the expiration as the sound fades there will be down stroke and there will be similar pattern of continuous wave form. Tracheal ventilation has two phases.

Graph for Oesophageal ventilation

It has an upstroke as air is pushed through oesophagus into the stomach. Since stomach does not have the property to recoil there is only one phase and down stroke follows immediately after upstroke or the parallel line prolongs.

Differentiation by sound :

Tracheal intubation will have two phases of sounds. Oesophageal intubation will have only one phase of sound and also there will be gurgling sound because of air and water in stomach that will be heard intensely.

Technological sequence :

Audio sensor — ► Sound amplification — ► Signal converting — ► Data accumulating — ► Data processing Display in computer screen .

Applied Physiology :

Two audio sensors are fixed in swiwel mount connector between patient (endotracheal tube) and ventilator. Simultaneous audio visual representation are appreciated and typical wave pattern of tracheal intubation having two phases and — t — Ii — [-appearance is differentiated from single phase and -IA — shaped narrow wave of oesophageal intubation. Continuos monitoring of ventilation is possible and there by this can be used in emergency situation _. and to diagnose endotracheal tube slipping during anaesthesia. Endotracheal tube position in intubated patient transfer in different situations can be diagnosed for endotracheal tube slipping immediately.

Salient features

1. It is a life saving, reliable , less expensive monitor which every operation theatre in the world can afford to have.

2. It is an instant display monitor and there is no need for calibration and therefore there will not be any time delay.

3. Lot of inadvertent deaths will be averted with the help of this monitor.