Kinder, gentler laryngoscopes

Caren B. Les, caren.les@laurin.com

A laryngoscope is a medical instrument designed to obtain a view of the vocal cords and the glottis, the space between the cords. It is typically incorporated in a medical procedure called orotracheal intubation, which is used to protect the airways and provide mechanical ventilation in patients who are comatose, anesthetized, injured or otherwise incapacitated. With the assistance of a laryngoscope, an endotracheal tube to help patients breathe is passed through the mouth, larynx and vocal cords into the trachea. The laryngoscope, of which there are many types, consists of a handle, incorporating batteries and an interchangeable blade with a light source.

Though generally safe, the highly invasive laryngoscopic intubations can be particularly difficult to perform in a small percentage of patients, and the apparatus has not been suitably sized for others. In response to these needs, researchers have stepped up to improve equipment to provide easier, more successful intubation to a broader range of patients.

Baby’s breath

To design a prototype miniaturized video laryngoscope for extremely low birth weight babies, Kate Baker, a graduate student researcher, and Joe Ford, a professor and principal investigator at the Photonic Systems Integration Laboratory at the University of California, San Diego, collaborated with Dr. Neil Finer, chief of the university’s division of neonatology, and Wade Rich, research coordinator for the division.

“The doctors work with premature infants, 85 to 90 percent of whom require intubation for breathing difficulties. They found that existing tools did not work well for the babies,” Baker said. “The main problem is having small enough optics with enough lighting and without dissipating too much heat,” she added.

Their device incorporates a 6-mm-wide curved acrylic tip to guide the breathing tube, an LED to illuminate the baby’s airway, and a 1.8-mm CCD imager at the end of the tube to help maneuver the tube and to teach others how to do the procedure. Baker said that their prototype has thus far been tried only on a mannequin and that they are working on a version that is suitable for testing in clinical trials. She added that they would eventually like to add wireless capability and possibly an adjustable angle to the device.

Easing intubation

The video rigid flexible laryngoscope, designed to make difficult intubations safer and less traumatic for patients, was developed by Dr. Harsha Setty, an anesthesiology resident, and Dr. Richard Schwartz, chairman of the emergency medicine department at the Medical College of Georgia in Augusta. “Some diseases, such as head and neck cancer, and some anatomical variations, such as shorter necks and buck teeth, can make tube placement more challenging,” according to Setty, who added that “one of the big problems with conventional laryngoscopes is that there is no method to see around obstructive tissue.”

Dr. Harsha Setty displays a laryngoscope that merges video and articulation to make difficult intubations easier. Photo courtesy of Medical College of Georgia.

“No other endotracheal intubation tool can articulate the endotracheal tube as effectively as [our device],” said Setty. The handheld battery-powered unit has an inline LCD and relies on distal chip imaging capability. The device also features a rigid cylindrical body with an illuminated LED camera module on one end and a video screen on the other. “It performs direct placement of the tube – where you are looking on the scope is where the tube advances every time,” said Setty. It can be used in various patient positions and also through supraglottic airway devices, he added.

The device is currently being used in operating and emergency rooms but also has the potential to be used in emergency rescue situations and for educational purposes.