2. Objectives
Importance of proper positioning in various surgical
procedures.
To know the appropriate patient positioning during general
and regional anesthesia.
Identify common injuries related to inappropriate
positioning.
To know the physiologic changes related to patient position.
3. 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.
Many patient positions that are used for surgery result in
undesirable physiologic consequences, including significant
cardiovascular and respiratory compromise.
Anaesthesia blunts natural compensatory mechanisms,
rendering surgical patients vulnerable to
positional changes.
4. Normally, as an individual reclines from an erect to a supine
position, venous return to the heart increases . Preload, stroke
volume, and cardiac output are augmented. The resultant
increase in arterial blood pressure activates afferent
baroreceptors (via the vagus nerve) and carotid sinuses (via the
glossopharyngeal nerve) to decrease sympathetic outflow and
increase parasympathetic impulses to the sinoatrial node and
myocardium. The result is a compensatory decrease in heart rate,
stroke volume, and cardiac output.
2 Mechanoreceptors from the atria and ventricle also are
activated to decrease sympathetic outflow to muscle and
splanchnic vascular beds. Lastly, atrial reflexes are activated to
regulate renal sympathetic nerve activity, plasma renin, atrial
natriuretic peptide, and arginine vasopressin levels. As a result,
systemic arterial blood pressure is maintained within a narrow
range during postural changes in the unanesthetized setting.
5. Physiological Changes Related to
Change In Body Position
Most changes are related to gravitational effects on RS and
CVS.
Changes in position redistribute blood within the venous,
arterial, and pulmonary vasculature.
Pulmonary mechanics also change with varying body
positions.
6. CVS
Changing from erect to supine increases venous return and
stroke volume in a nonanaesthetised person.
Obesity, pregnancy, and abdominal tumors can reduce venous
return (preload) when in the supine position.
7. RS
Anesthetized patients who are breathing spontaneously have
a reduced TV and FRC and an increased CV compared with
the nonanesthetized state.
Positive-pressure ventilation with muscle relaxation may
ameliorate V/Q mismatches under GA by maintaining
adequate MV and limiting atelectasis.
Hence assisted ventilation is superior to unassisted
ventilation when patient is anaesthetized.
10. Supine
A significant portion of our life is spent in supine position.
This position is not usually considered to pose significant
physiologic stress on the body.
However, patients with morbid obesity, mediastinal masses,
or poor cardiac function prone to aortocaval compression do
not easily tolerate this position.
11. Supine
Patient is on his or her back.
Arms on arm boards
Check orientation of arm (arms < 90 degrees)
Make sure arm is supinated (palm up)
Place additional padding under elbow
Arms tucked
Check fingers
Check IV lines and SpO2 probe
12. Variations of Supine Position
Trendlenberg’s Position (head down)
Reverse Trendlenberg’s Position (head up tilt)
Lawn chair Position
Frog leg Position
13. Trendlenberg’s Position
Tilting a supine patient head down, 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 through IJV.
19th century German surgeon, Trendelenburg, who described
its use for abdominal surgery.
Nonsliding mattresses are recommended to prevent the
patient from sliding cephalad.
14. Trendlenberg’s Position
Increase in central venous, intracranial, and intraocular
pressures.
Swelling of the face, conjunctiva, larynx, and tongue with an
increased potential for postoperative upper airway obstruction.
The cephalic movement of abdominal viscera against the
diaphragm also decreases FRC and pulmonary compliance.
Intubation with ET tube is preferred to protect the airway from
aspiration and to reduce atelectasis.
It is advised to verify an air leak around the ET tube.
15. Complications
Backache in patients under supine position for long periods
results from loss of normal lordotic curvature of the lumbar
spine because of reduced tone of paraspinal muscles and
ligaments.
Elderly patients with pre-existing lower back pain problems or
lumbar spinal stenosis.
Using the lawn chair position or placing a pillow under the knees
in the standard supine position may reduce the incidence of back
ache.
Pressure Alopecia
16. To facillate upper abdominal surgery by shifting the
content caudally.
Reduce perfusion pressure to brain, so monitoring BP
properly.
Reverse trendlenberg
position(Head up tilt)
17. Frog leg position
Hip and knee are flexed,sole of the feet facing each
other allow ascess to perineum,genitalia and rectum.
18. Lawn Chair Position
* Lower and upper halves of the body are slightly elevated in
relationship to the hips.
* An additional advantage of this position is the greater degree
of abdominal musculature relaxation, which is facilitated by the
shortened distance from the xiphoid process to symphysis pubis
and easy closing of laparotomy incision.
20. Prone
Face down
HEAD PLACEMENT
Head straight forward
ET tube placement and patency should be checked periodically.
Check bilateral eyes/ears for pressure points
Head turned
Check dependent eye/ear and ETT placement
Be aware of potential vascular occlusion
21. Positioning Aids and Supports
Pin (Mayfield) head holder
Radiolucent pin head holder
Horseshoe head rest
Foam head support (e.g., Voss, O.S.I., Prone-View)
Vacuum mattress (“bean bag”)
Wilson-type frame
Andrews (“hinder binder”)-type frame
Relton -Hall (four-poster) frame
22. Prone
Arm placement
Tucked – similar concerns to supine
Abducted
Check neck rotation and arm extension to avoid possible brachial
plexus injury.
Make sure elbows are padded.
Iliac support
Make sure some sort of padding is placed under iliac crests.
24. Prone position is for surgical ascess to the post. fossa
of skull, post. Spine, buttocks, perineal area and lower
extremities.
25. Prone
With the coordination of the entire operating room
staff, the patient is turned prone onto the operating
room table, keeping the neck in line with the spine
during the move. The anaesthesiologist is primarily
responsible for coordinating the move and for
repositioning of the head.
29. Lateral
Lateral (park bench)
Semi lateral (Janetta)
Patient on side (lateral decubitus position)
i.e. left lateral decubitus position means right side up
Most important consideration is to maintain body
alignment
Keep neck in neutral position
Always place axillary roll (Misnomer)
Place padding between knees
Try and place padding below lateral aspect of dependent leg
(prevent peroneal nerve damage)
30. Lateral
Position the arms parallel to each other
Place padding between arms or place non-dependent are on
padded surface
Check pulses
SpO2 and NIBP in both the arms
-lateral positionis for surgery hip,thorax and retroperitoneal str.
31. Lateral
In a patient who is mechanically ventilated, the combination
of the lateral weight of the mediastinum and disproportionate
cephalad pressure of abdominal contents on the dependent
lung favours over ventilation of the nondependent lung.
At the same time, pulmonary blood flow to the under
ventilated, dependent lung increases owing to the effect of
gravity.
Consequently, ventilation-perfusion matching worsens,
potentially affecting gas exchange and ventilation.
33. Lithotomy
The classic lithotomy position is frequently used during
gynecologic, 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.
42. .
The mean arterial pressure (MAP) at a measurement site
varies by 2 mmHg with each vertical inch above or
below the atrium
43. Lithotomy
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.
44. Lithotomy
Common Peroneal nerve injury
Compartment Syndrome
Normal lordotic curvature is lost so aggravating any previous
lower back pain.
Abdominal viscera displace diap. Cephaled reducing lumg
compliance and tidal volume.
47. Sitting
Position used in neurosurgery to facilitate access to posterior
fossa and cervical spine.
Variant - Beach chair position.
48. Sitting
The hemodynamic effects of placing a supine patient in the
sitting position are dramatic.
Because of the pooling of blood into the lower body under
general anaesthesia , patients are particularly prone to
hypotensive episodes.
Incremental positioning and the use of intravenous fluids,
vasopressors, and appropriate adjustments of anaesthetic
depth can reduce the degree and duration of hypotension.
Elastic stockings and active leg compression devices can help
maintain venous return.
49. Sitting
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.
50. Excessive cervical flexion
It can impede arterial and venous blood flow, causing
hypoperfusion or venous congestion of the brain.
Obstruct the ET tube and place significant pressure on the
tongue, leading to edema.
Generally, maintaining at least two fingers' distance between
the mandible and the sternum is recommended.
If TEE is used for air embolism monitoring because the
oesophageal probe lies between the flexed spine and the
airway, adding potential for compression of laryngeal
structures and the tongue.
51. Pneumocephalus
Air enters into the supratentorial space, much as air enters
an inverted bottle.
Tension pneumocephalus is one of the causes of delayed
awakening or nonawakening after posterior fossa and
supratentorial procedures.
N2O – Contraindicated?
The diagnosis of pneumocephalus is confirmed by a brow-up
lateral x-ray or CT scan.
The treatment is a twist-drill hole followed by needle
puncture of the dura.
52. Venous air embolism
VAE is detectable by precordial Doppler in approximately
40% of patients and by TEE in 76% of patients.
The rate of VAE is apparently lower with cervical
laminectomy (25% using TEE in the sitting position versus
76% for posterior fossa procedures.
Transverse and sigmoid sinuses
53. Monitoring
The monitors employed for the detection of VAE should provide
(1) a high level of sensitivity
(2) a high level of specificity
(3) a rapid response
(4) a quantitative measure of the VAE event
(5) an indication of the course of recovery from the VAE event.
The combination of a precordial Doppler and expired CO2
monitoring meet these criteria and are the current standard of
care.
TEE is more sensitive than precordial Doppler to VAE and offers
the advantage of identifying right-to-left shunting of air.
54. Signs and Symptoms
No physiologic change – TEE, Doppler
Modest physiologic change – EtCO2, PAP
Clinically apparent changes – CO, CVP
Cardiovascular Collapse – BP, ECG
55. Management
Prevent further air entry
Notify surgeon (flood or pack surgical field)
Jugular compression
Lower the head
Treat intravascular Air
Aspirate right heart catheter
Discontinue N2O
FIO2: 1.0
Pressors/ inotropes
Chest compression
56. NERVE INJURIES
Peripheral nerve injury, although rare, accounted for 18% of
cases in the 1990-1994 ASA Closed Claims Database, second
only to death.
Peripheral nerve injury is often a result of patient positioning.
The mechanisms of injury are stretching, compression, and
ischemia.
Ulnar neuropathy is the most common postoperative nerve
injury, followed by injury to the brachial plexus, lumbosacral
nerve roots, and spinal cord.
57. Specific forms of nerve injury
Brachial Plexus Injury
Pathophysiology: Supine Position
Excessive stretching due to relative
positioning of the patient’s head and
arm.
Position of Head: Extension and
Lateral Flexion of the head to opposite
side with the patient supine.
Positioning of Arm: Abduction,
External rotation and Extension
58.
59. Pathophysiology: Lateral Decubitus
Compression plays a predominant role in injury with the
patient in the lateral decubitus position when the plexus is
compressed against the thorax by the humeral head.
An axillary roll traditionally used to support the thorax
wall so as to prevent compression of the neurovascular
bundle.
Brachial plexus lesions most frequently involve the upper
nerve roots with corresponding symptoms and signs
60. Ulnar nerve injury
Ulnar nerve injury most
commonly occurs because of its
superficial path along the
medial epicondyle of the
humerus.
Direct Trauma: The ulnar nerve
is particularly vulnerable to
compression against the
operating table, especially if the
forearm is extended and pronated.
Indirect Trauma: Injuries may
also occur when the nerve is
stretched around the medial
epicondyle during extreme
61. Radial nerve injury
Radial nerve lesion usually occurs as a result of compression
of the nerve between the edge of the operating table and
the humerus (in the radial groove due to patient’s arm
hanging off the edge of the table). Also known as
‘Saturday Night Palsy’.
62. It may occur when the patient is in the lateral position
and the uppermost arm is abducted beyond 90o and
suspended from a vertical screen support.
63. Sciatic nerve injury
Predisposing Factors:
Thin Patient
Prolonged Surgery
Opposite buttock is
elevated as in the hip
pinning position.
Given the conditions the
Sciatic nerve is compressed
at the sciatic notch where
it passes anterior to
posterior.
In the lithotomy position
maximal external
rotation of the flexed
64. Common peroneal
nerve injury
This is the most frequently
damaged nerve in the lower
limb.
It may be compressed
against the head of the
fibula in the lithotomy
position or between the
fibula and the operating
table, a particular risk
associated with the lateral
position.
65. Facial nerve Injury
Facial nerve, which may be
compressed against the
ascending ramus of the
mandible when the
anaesthetist holds the jaw
forward to maintain an
airway.
66. Lingual Nerve Injury
Lingual nerve damage following
use of Laryngeal Mask Airway
as well as I-gel is a rare
complication.
Explained by :
Pressure from the tube in the
buccal cavity.
Excessive pressure of the
pharyngeal cuff of LMA against
oropharyngeal mucosa.
Due to an pressure against the
inner aspect of the mandible by the
inflated cuff.
67. Less common nerve injuries
• Tibial nerve in the popliteal fossa.
• Supraorbital nerve by a tight head harness used
in neurosurgery .
68. Prevention of nerve injuries in an
Anaesthetized Patient
Proper positioning during surgery is extremely
important to prevent nerve injury.
Meticulous care should be taken when positioning
patients to avoid compression of superficial nerves
from arm boards, leg stirrups or retractors.
Padding should be used beneath tourniquets and over
pressure points and extreme joint positions, particularly of
the shoulder and head, should be avoided.
Tourniquet time must also be carefully monitored. The
tourniquet should not remain inflated for more than two
hours at a time. The anesthesiologist alerts the surgeon at
the end of each hour. If the tourniquet is needed after two
hours, it's deflated for about 15 minutes.
.
69. Nerve Interventions
Brachial plexus Abduct arms to no more than 90 degrees.
Minimize simultaneous abduction, external arm rotation, and
opposite lateral head rotation.
In prone position, maintain abduction and anterior flexion of
arms above head to no more than 90 degrees.
In lateral position, place chest roll under lateral thorax to
minimize compression of humerus into axilla.
Ulnar nerve Avoid compression of condylar groove area.
Elbow flexion to no more than 110 degrees.
Radial nerve Avoid pressure on posterior and lateral humerus.
Median nerve Avoid excessive wrist dorsiflexion.
Sciatic nerve Limit external hip rotation.
Flex knees over towel rolls/pillows when hips are flexed.
Common peroneal nerve
(common fibular nerve)
Avoid compression on lateral knee at the fibular head,
especially in lateral and lithotomy positions.
Tibial nerve Avoid compression on popliteal fossa.
70. Ulnar Nerve Injury
Most common nerve injury in anesthetized patient.
Often injured when compressed between the posterior aspect of
medial epicondyle of elbow and arm board or bed.
More likely with elbow flexed or forearm pronated.
Symptoms include loss of sensation of lateral portion of hand
and inability to abduct or oppose the fifth finger (claw hand).
71. Brachial plexus nerve injury
Second most common type of nerve injury
Injury occurs often when plexus is stretched or compressed
between the clavical and first rib
Seen in prone and supine procedures where head rotated and
laterally flexed to the same side and/or arm is extended
posteriorly past the plane of the torso
72. Brachial plexus nerve injury
Manifestations depend on which nerves are injured in the
plexus:
Median – “Ape hand” deformity, inability to oppose thumb
Axillary – inability to abduct the arm
Ulnar – “Claw hand” deformity
Musculocutaneous – inability to flex forearm
Radial – wrist drop
73. Cosmetic Problems
Skin breakdown due to prolonged positioning
Make sure bony prominences are well padded
Avoid direct focused pressure on scalp (can lead to alopecia) ?
Head straps?
