2. ❖Patient positioning is a major responsibility that is
shared by the entire operating room team. A balance
between optimal surgical positioning and patient
well-being is sometimes required.
❖Patient’s position during anesthesia care should be
natural- one that would be well tolerated if the
patient were awake and unsedated.
3. ❖ Anaesthesia blunts natural
compensatory mechanisms,
rendering surgical patients
vulnerable to positional changes.
❖ Positions meant optimal for
surgery often result in undesirable
physiologic changes such as
hypotension from impaired venous
return to the heart or oxygen
desaturation as a result of
ventilation perfusion mismatching.
❖ Peripheral nerve injuries during
surgery remain a significant source
of perioperative morbidity.
4. PHYSIOLOGICALCHANGES RELATED
TO CHANGEINBODYPOSITION
❖Most changes are related to gravitational effects
on cardiovascular system and respiratory
system.
❖Changes in position redistribute blood within the
venous, arterial, and pulmonary vasculature.
❖Pulmonary mechanics also change
with varying body positions.
7. ❖ Most common with the least amount of harm
❖ Placed on back with legs extended and
uncrossed at the ankles
❖ Spinal column should be in alignment with legs
parallel to the bed
✓ Head in line with the spine and the face is
upward
8. Associated arm
position:
✓ Arms either on arm boards
abducted <90 degrees to
minimize the likelihood of
brachial plexus injury.
✓ When arms are adducted,
they are usually held
alongside the body.
9. CONCERNS IN SUPINE POSITION
❖ Greatest concerns are circulation and pressure points
❖ Most Common Nerve Damage:
✓ Brachial Plexus: positioning the arm >90*
✓ Radial and Ulnar: compression against the OR bed,
metal attachments, or wh en team members lean
against the arms during the procedure
✓ Peroneal and Tibial: Crossing of feet and plantar
flexion of ankles and feet
❖ Vulnerable Bony Prominences:
(due to rubbing and sustained pressure)
✓ Occiput, spine, scapula, Olecranon, Sacrum,
Calcaneous
10. CARDIOVASCULAR CONCERNS
Cardiac output ↑ on assuming supine position
Venous blood from lower body
flows back To heart
↓
Stretches atrial wall
↓
Stroke volume ↑
↓
↑ blood pressure
11. Baroreceptors in Aorta
↓ via
Vagus nerve
Baroreceptors in Carotid
↓ via sinu s
Glossopharyngeal nerve
↑ Parasympathetic activity
↓
↓ HR ↓SV ↓Contractility
↓
Little change in BP noted
(clinically normal BP observed)
12. ❖In General anaesthesia, muscle relaxation,
positive pressure ventilation, and neuraxial
blockade all interfere with venous return to the
heart, arterial tone, and autoregulatory
mechanism.
❖Therefore, arterial blood pressure is often labile
immediately after the start of anesthesia and during
positioning.
14. ❖Anesthetized person who are spontaneously
breathing—
↓Tidal Volume
↓Functional residual capacity
❖Positive pressure ventilation with muscle relaxation
may ameliorate ventilation perfusion mismatches
under GA by maintaining adequate minute
ventilation.
❖Perfusion appears to follow a central-to-peripheral
spectrum in each lobe that is maintained with
changes in cardiac output.
❖Also, gravity affects the preferential perfusion of the
dependent portions of the lungs.
16. TRENDELENBURG POSITION
❖Tilting a supine patient head down, the Trendelenburg
position, is often used to increase venous return during
hypotension, to improve exposure during abdominal and
laparoscopic surgery, and to prevent air emboli and
facilitate cannulation during central line placement.
❖ The Trendelenburg position has significant cardiovascular
and respiratory consequences.
✓ The head-down position
✓ Increases central venous, intracranial, and intraocular
pressures.
❖ Prolonged head-down position also can lead to swelling of
the face, conjunctiva, larynx, and tongue with an
increased potential for postoperative upper airway
obstruction.
17. ❖ The cephalic movement of abdominal viscera against the
diaphragm also decreases functional residual capacity
and pulmonary compliance.
❖ In spontaneously ventilating patients, the work of
breathing increases.
❖ In mechanically ventilated patients, airway pressures
must be higher to ensure adequate ventilation.
❖ The stomach also lies above the glottis. Endotracheal
intubation is often preferred to protect the airway from
pulmonary aspiration related to reflux and to reduce
atelectasis.
❖Because of the risk of edema to the trachea and mucosa
surrounding the airway during surgeries in which
patients have been in the Trendelenburg position for
prolonged periods, it ma y be prudent to verify an air leak
around the endotracheal tube or visualize the larynx
before extubation.
18. REVERSE TRENDELENBURGPOSITION
❖Reverse Trendelenburg position (head-up tilt) is often
employed to facilitate upper abdominal surgery by
shifting the abdominal contents caudad.
❖This position is increasingly popular because of the
growing number of laparoscopic surgeries.
❖Caution is advised to prevent patients from slipping
on the table, and more frequent monitoring of arterial
blood pressure may be prudent to detect
hypotension owing to decreased venous return.
❖In addition, the position of the head above the heart
reduces perfusion pressure to the brain and should
be taken into consideration when determining
optimal blood pressure.
19. ❖In all positions in which the head is at a different
level than the heart, the effect of the hydrostatic
gradient on cerebral arterial and venous pressures
should be carefully considered in terms of cerebral
perfusion pressure.
20. Trendelenburg position and reverse Trendelenburg
position. Shoulder braces should be avoided to
prevent brachial plexus compression injuries
21. COMPLICATIONS
❖Pressure alopecia:
Lumps, such as those caused by monitoring cable
connectors, should not be placed under head padding
because they may create focal areas of pressure.)
❖Backache :
as the normal lumbar lordotic curvature, particularly
the tone of the paraspinous musculature, is lost
during general anesthesia with muscle relaxation or a
neuraxial block.
❖Tissues overlying all bony prominences, such as the
heels and sacrum, must be padded to prevent soft
tissue ischemia owing to pressure, especially during
prolonged surgery.
22. ❖Peripheral nerve injury :(Ulnar neuropathy is the
most common lesion.)
✓ Regardless of the position of the upper extremities,
maintaining the head in a relatively midline
position can help minimize the risk of stretch
injury to the brachial plexus.
✓ limiting arm abduction in supine patient to less
than 90 degrees at the shoulder with the hand
and forearm either supinated or kept in neutral
position
23. LITHOTOMY
❖The classic lithotomy
position is frequently
used during
gynaecologic, rectal, and
urologic surgeries.
❖The hips are flexed 80 to
100 degrees from the
trunk, and the legs are
abducted 30 to 45
degrees from the midline.
24. ❖Initiation of the lithotomy position requires
coordinated positioning of the lower extremities by
two assistants to avoid torsion of the lumbar spine.
❖Both legs should be raised together, flexing the hips
and knees simultaneously.
❖After the surgery, the patient must be returned to the
supine position in a coordinated manner. The legs
should be removed from the holders simultaneously,
knees brought together in the midline, and the legs
slowly straightened and lowered onto the operating
room table.
26. ❖When the legs are elevated, preload increases,
causing a transient increase in cardiac output and,
to a lesser extent, cerebral venous and intracranial
pressure in otherwise healthy patients.
❖In addition, the lithotomy position causes the
abdominal viscera to displace the diaphragm
cephalad, reducing lung compliance and potentially
resulting in a decreased tidal volume.
27. ❖If obesity or a large abdominal mass is present
(tumor, gravid uterus), abdominal pressure may
increase significantly enough to obstruct venous
return to the heart.
❖the normal lordotic curvature of the lumbar spine
is lost in the lithotomy position, potentially
aggravating any previous lower back pain.
❖Lower extremity compartment syndrome may
rarely occur.
30. ❖The lateral decubitus position is used most
frequently for surgery involving the thorax,
retroperitoneal structures, or hip.
❖The patient’s head must be kept in a neutral position
to prevent excessive lateral rotation of the neck and
stretch injuries to the brachial plexus.
❖The dependent ear should be checked to avoid
folding and undue pressure.
❖It is advised to verify that the eyes are securely
taped before repositioning if the patient is asleep.
31. ❖The dependent eye must be checked frequently for
external compression.
❖Watch for compression of the dependent axillary
structures.
( the pulse should be monitored in thedependent
arm for early detection of compression to axillary
neurovascular structures.)
❖Vascular compression and venous engorgement in
the dependent arm may affect the pulse oximetry
reading, and a low saturation reading may be an
early warning of compromised circulation.
32. ❖ When a kidney rest is used, it must be properly placed
under the dependent iliac crest to prevent inadvertent
compression of the inferior vena cava.
❖a pillow or other padding is generally placed
between the knees with the dependent leg flexed to
minimize excessive pressure on bony prominences
and stretch of low extremity nerves.
33. ❖The lateral decubitus position also is associated
with pulmonary compromise. In a patient who is
mechanically ventilated,
✓lateral weight of the mediastinum
✓disproportionate cephalad pressure of
abdominal contents on the dependent lung
favors overventilation of the nondependent lung
✓pulmonary blood flow to the
underventilated, dependent lung
increases owing to the effect of gravity.
✓ventilation-perfusion matching worsens
35. ❖Used primarily for surgical access to the posterior
fossa of the skull, the posterior spine, the buttocks
and perirectal area, and the lower extremities.
❖As with the supine position, if the legs are in plane
with the torso, hemodynamic reserve is maintained
❖Pulmonary function may be superior to the supine or
lateral decubitus positions if there is no significant
abdominal pressure and the patient is properly
positioned.
36. ❖The legs should be padded and flexed slightly at the
knees and hips. The head may be supported face-
down with its weight borne by the bony structures or
turned to the side.
❖Both arms may be positioned to the patient’s sides
and tucked in the neutral position or placed next to
the patient’s head on arm boards.
❖Extra padding under the elbow is needed to prevent
compression of the ulnar nerve.
❖The arms should not be abducted greater than 90
degrees to prevent excessive stretching of the
brachial plexus.
❖elastic stockings and active compression devices
are needed for the lower extremities to minimize
pooling of the blood, especially with any flexion
of the body.
37. ❖ When general anesthesia is planned, the patient is first
intubated on the stretcher, and all intravascular access is
obtained as needed.
❖ The endotracheal tube is well secured to prevent
dislodgment and loosening of tape owing to drainage of
saliva wh en prone.
❖ With the coordination of the entire operating room
staff(minimum of 5), the patient is turned prone onto the
operating room table, keeping the neck in line with the
spine during the move.
The anesthesiologist is primarily responsible for
coordinating the move and for repositioning of the head.
❖It is recommended to disconnect blood pressure cuffs and
arterial and venous lines that are on the side that rotates
furthest to avoid dislodgment.
❖ Full monitoring should be reinstituted as rapidly as
possible.
❖ Endotracheal tube position and adequate ventilation are
reassessed immediately after the move.
38. ❖Because the abdominal wall is easily displaced,
external pressure on the abdomen may elevate intra-
abdominal pressure in the prone position.
❖External pressure on the abdomen may push the
diaphragm cephalad, decreasing functional residual
capacity and pulmonary compliance, and increasing
peak airway pressure.
❖Abdominal pressure also may impede venous return
through compression of the inferior vena cava
❖As such careful attention must be paid to the ability
of the abdomen to hang free and to move with
respiration.
❖The prone position presents special risks for
morbidly obese patients, whose respiration is
already compromised, and who may be difficult to
reposition quickly.
40. COMPLICATIONS
❖Airway
• Accidental extubation
• Obstruction of ETT
bloody secretions/
sputum plugs
• Facial, Airway edema
Prolonged head low
position, ↑ crystalloid
infusion
Problems with
extubation
53
41. ❖ Visual loss
❖Neck injury
Excessive lateral torsion or hyperflexion → Post-op
pain, cervical nerve root or vascular compression
❖Accentuation of pre-existing trauma
Multiple skeletal injuries may be further
exacerbated during positioning
54
43. ❖The sitting position (although infrequently used
because of the perception of risk from venous and
paradoxical air embolism, offers advantages to the
surgeon in approaching the posterior cervical spine
and the posterior fossa.)
❖The main advantages of the sitting position over the
prone position for neurosurgical and cervical spine
surgeries are;
✓ excellent surgical exposure
✓ decreased blood in the operative field
✓ reduced perioperative blood loss.
✓ superior access to the airway, reduced facial
swelling, and improved ventilation, particularly in
obese patients.(to the anesthesiologist)
44. ❖The head may be fixed in pins for neurosurgery or
taped in place with adequate support for other
surgeries.
❖Arms must be supported to the point of slight
elevation of the shoulders to avoid traction on the
shoulder muscles and potential stretching of upper
extremity neurovascular structures.
❖The knees are usually slightly flexed for balance and
to reduce stretching of the sciatic nerve, and the feet
are supported and padded.
❖Because of the pooling of blood into the lower body
under general anesthesia patients are particularly
prone to hypotensive episodes.
45. ❖Head and neck position has been associated with
complications during surgery to the posterior spine or
skull in the sitting position.
❖Excessive cervical flexion has numerous adverse
consequences.
✓ It can impede arterial and venous blood flow,
causing hypoperfusion or venous congestion of the
brain.
✓ It may impede normal respiratory excursion.
✓ Excessive flexion also can obstruct the
endotracheal tube and place significant pressure
on the tongue.
46. ❖Because of the elevation of the surgical field above
the heart, and the inability of the dural venous
sinuses to collapse because of their bony
attachments, the risk of venous air embolism is a
constant concern.
❖Arrhythmia, desaturation, pulmonary hypertension,
circulatory compromise, or cardiac arrest may occur.
47. ❖Potential complications from sitting position
✓ Venous air emboli.
Need to take measures to detect and extract
VAE
✓ Hypotension.
✓ Brainstem manipulations resulting in
hemodynamic changes.
✓ Risk of airway obstruction.
✓ Macroglossia.
✓ Pneumocephalus
✓ Quadriplegia.
48. BEACHCHAIR POSITION
❖ Used for shoulder
surgeries including
arthoscopies.
❖ Superior access to
shoulder
❖ Associated with
neurologic injury,
cervical neurapraxia,
and hypotensive
bradycardia
(epinephrine
containing
interscalene block)
49. PHYSIOLOGICAL CHANGES IN
LAPROSCOPIC SURGERY
• Increased intra-abdominal pressure results in cephalad
displacement of diaphragm, reducing FRC and compliance. Peak
airway pressure and plateau pressure rises. This results in increase
airway resistance and work of breathing.
• Hypoxemia may result from atelectasis and intrapulmonary
shunting, more common in obese patient and with underlying
cardiopulmonary disease.
• Minute ventilation increases.
• Hemodynamically, venous return decreases, systemic vascular
resistance increases; this increases arterial pressure.
• Cardiac output decreases.
• Cardiac arrhythmias can be due to – hypercapnia, peritoneal
stimulation, reduced venous return, hypovolemia and venous gas
embolism.
50. POSITIONING DURING ROBOTIC
SURGERY
• POSITIONALVARIATIONS : although robotic surgery is often performed in conventional
positions, some proceduresrequire extremes of these positions like lithotomy with
steep trendelenburg (prostatectomy),varying degrees of reverse trendelenburg
(gastrectomy),varying degrees of lateral decubitus position (thoracicsurgery).
• Prior to positioning all additional intravenous access and invasive monitoring devices
should be obtained. Once the procedure has begun, there will be lii=mited access to
these devices.
• During operation, any unanticipatedmovement could cause serious harm to patient.
• The extreme and often steeper positions put patients at risk of sliding off the operating
table.
• The use of shoulder braces should be avoided due to increased risk of brachial plexus
injury.
• Use of chest bandings or belts should ne favoured to secure patient to the operating
room table.
• Any potential site of injury should be padded or protected.
51.
52. PHYSIOLOGICAL CHANGES
• In robotic assisted surgery, physiological changes are often present as exaggerationsof
common physiologic changes seen during non-roboticassisted surgery.
• The addition of CO2 pneumoperitoneum can amplify these changes
• With respiratory system,steep trendelenburg and pneumoperitoneum decreases FRC
and lung compliance via encroachment of abdominal cavity onto diaphragm.
• This position increases the risk of V/Q mismatch.
• Functionallength of trachea decreases by 1 cm, possibly leading to mainstem
intubation and hypoxia after the patient is positioned.
• In cardiovascularsystem,it can increase central venous pressure, pulmonary artery
pressure and pulmonary capillary wedge pressure. It also increases cardiacoutput
secondary to increased venous return.
• However, addition of pneumoperitoneum increases systemic vascular resistance,
potentially decreasing cardiacoutput.
• In reverse trendelenburg position, it can lead to hypotension due to decreased venous
return to the heart. The patient’sblood pressure must be careful maintained to allow
adequate cerebral perfusion
• Pneumoperitoneum insufflation as well insufflation within the thoraciccavity also can
lead to hypotension via obstructingvenous return. This is also exaggeratedby placing
the patient in the lateral decubitus position with overall head up position.
