Sellick’s manoeuvre works, ‘though he was a bit off on the anatomy’
You might not know what it’s called, but if you’ve had general
anaesthesia before surgery, especially after an accident, it is likely
you have received Sellick’s manoeuvre. That’s when fingers are pressed
against a patient’s throat to prevent regurgitation and spilling of
stomach contents into the airway and lungs while anaesthesia is being
Such regurgitation could result in serious lung damage and even death.
The manoeuvre is a longstanding practice, first described in 1961 by
British physician Brian Sellick. Performed dozens of times a day in
hospitals, the procedure is accepted as ‘standard of care’ and is a
basic skill taught in all anaesthesiology training programmes.
Anaesthesiologists estimate conservatively that more than 100,000 people
a year undergo the procedure.
But recently some physicians have begun to question the technique in the
wake of a study challenging its effectiveness and ease of execution. And
some have stopped using it altogether.
Now, researchers from University of Florida College of Medicine have
used magnetic resonance imaging of the neck region to show that the
manoeuvre works and that doubts about its effectiveness are based on a
misunderstanding of what physical changes happen in the neck during the
“Sellick was right that the manoeuvre works, but he was a bit off on the
anatomy,” said UF anaesthesiologist Mark J. Rice, MD, who led the study
published in the November 2009 edition of the journal Anesthesia and
Also called cricoid pressure, the eponymous manoeuvre has for decades
been described as the pinching of the oesophagus between the cricoid – a
ring of cartilage that surrounds the trachea – and the neck vertebrae.
It is most often used in accident victims whose stomachs might not be
empty before surgery, or in patients who have bowel obstructions or
slowed emptying of the stomach because of certain drugs or medical
Some doctors say that the procedure is hard to get right, and that not
applying enough pressure and at a proper angle would cancel out any
A 2003 paper further cast strong doubt on the procedure’s effectiveness
with a finding that in 90% of cases, the oesophagus moves to the side
during the procedure. It is generally thought that the procedure is
effective only if done at the midline of the neck. So researchers
concluded that such movement of the oesophagus means the manoeuvre can’t
effectively prevent regurgitation.
The UF researchers used open MRI imaging of the neck while the procedure
was administered to volunteers. That allowed the person performing the
technique to do so unimpeded, and increased the chance of reproducing
how the procedure is carried out in a clinical setting.
It turns out, the imaging studies show, that the oesophagus does not
exist at that point in the neck where the procedure is done. Instead, it
is a structure called the hypopharynx – above the oesophagus – that gets
pinched between the cricoid and the bones of the neck. The oesophagus
exists only lower down, near the shoulders. So movement of the
oesophagus doesn’t affect the procedure since it is not involved, Rice
and coauthors Lori Deitte, MD, Anthony Mancuso, MD, Nikolaus Gravenstein,
MD, Charles Gibbs, MD, and Timothy Morey, MD found.
“This is a major error that’s been in the literature for 50 years,” said
Rice, who is chief of liver transplantation in UF’s department of
anaesthesiology. As for the sideways movement, the study showed that the
hypopharynx and cricoid structures move together, so effective
compression is achieved even if it is pushed to the side in the process.
“It turns out it doesn’t matter,” Rice said. The new findings serve to
reassure doctors that the procedure works, and that they don’t have to
do it ‘perfectly’ for it to be effective.
“Astonishingly enough, our previous assumptions are totally wrong,” said
professor Scott Springman, M.D., director of ambulatory anaesthesia at
the University of Wisconsin- Madison. “Now I can explain to my residents
more accurately why we’re doing it.
I will use it in more situations than I would if I still had grave
doubts about its efficacy.” Although the study doesn’t prove directly
that Sellick’s manoeuvre prevents regurgitation, that is reasonably
inferred from the images.
“Because of Dr Rice’s study, Sellick’s manoeuvre has again been shown to
have anatomic efficacy, despite it occurring in a way that is different
from the classic description,” Springman said. “It also shows us that
previous assumptions are not always correct, and that new technology can
help us refine our hypotheses.”
of upload: 20th April 2010