Patient Positioning - Anesthesia, position

anesthesia

1. PATIENT POSITIONING PGI Ivan Bandiola

2. Patient positioning is a substantial responsibility that requires the coordination of the entire medical team. A balance between optimal surgical positioning and patient well-being is required. a compromise between what the patient can tolerate and what the surgical team requires It is important to adapt an optimal positioning as it can prevent adverse patient outcomes May cause tissue damage Stretching nerves to 5% greater than normal resting length can lead to ischemia Point pressure may reduce local blood flow Use of padding - most common way to reduce point pressure Patient positioning and postural limitations should be assessed during the preoperative evaluation INTRODUCTION

3. To promote proper physiological alignment To maintain patient’s airway and avoid constriction on the chest cavity To minimize interference with circulation To gain optimum exposure to operative and anesthetic sites To protect skeletal and neuromuscular structures To provide comfort, stability, safety and dignity to the patient. GOALS OF PROPER POSITIONING

4. The patient’s position during anesthesia care should be neutral-one that would be well tolerated if the patient were awake and unsedated Weight-bearing surfaces and joints should be well padded and curvatures including the lumbar spine should be supported The head should be in midline without substantial flexion and extension. Eyes should be closed without external pressure. Tilting of the table before draping, using safety straps and prevention of falls from the table are fundamental GENERAL CONSIDERATIONS

5. We should assess the following prior to positioning of the patient: Duration of the surgery Surgeon’s preference of position Required position for procedure Anesthesia to be administered Patient’s risk factors (age, weight, skin condition, pre-existing conditions, etc.) Basics of anatomy and physiology ASSESSMENT

6. TABLE ACCESSORIES AND ATTACHMENTS

7. PHYSIOLOGICAL CHANGES RELATED TO CHANGES IN BODY POSITION Most changes are related to gravitational effects on cardiovascular system and respiratory system. Alterations in position redistribute blood within the venous, arterial and pulmonary vasculature Pulmonary mechanics and pulmonary perfusion also vary with different body positions

8. Anesthetized persons who are spontaneously breathing have a reduced TV, FRC, and increased closing volume Positive pressure ventilation with muscle relaxation may ameliorate ventilation-perfusion mismatches under GA by maintaining adequate minute ventilation Gravity affects the preferential perfusion of the dependent portions of the lung

9. SUPINE POSITION

10. Most commonly used position for surgeries. The head, neck and spine all retain neutrality Arms can be abducted, adducted but should be placed in as neutral as possible When adducted arms are securely placed next to the body. Abducted arms are kept on arm boards beside the table Attention should be given to pad bony prominences POSITIONING

11. Abduction should be limited to less than 90 degrees to minimize brachial plexus injury. ARM POSITIONING When arms are adducted, they are usually held alongside the body with a “drawsheet” that passes under the body.

12. Patient’s hips at the break of the table. Reduces stress on back, hips and knees as the are in flexed position. Sometimes this position is better tolerated than full supine position Better venous drainage in lower limb as they are slightly over the level of the heart Abdominal wall tension is reduced, as xiphoid to pubic distance is reduced LAWN CHAIR POSITION

13. Allows the access to the perineum, medial thighs, genitalia and rectum. Positioned supine, hips and knees are flexed with hips externally rotated and soles facing each other. Care must be taken to minimize stress and postoperative pain in the hips and to prevent dislocation by appropriately supporting the knees. FROG LEG POSITION

14. Frequently used to improve exposure during abdominal and laparoscopic surgeries Position produces hemodynamic and respiratory changes This position is often preferred during central line placement to prevent air embolism and to offset hypotension by temporarily increasing venous return. The cephalad movement of diaphragm decreases FRC, thus, decreasing pulmonary compliance. TRENDELENBURG POSITION

15. This position increases CVP, ICP, IOP, and can have significant respiratory consequences In spontaneously ventilating patients, the work of breathing increases In mechanically ventilated patients, airway pressures must be higher to ensure adequate ventilation Prolonged head down can lead to swelling of face, conjunctiva, larynx and tongue with an increased potential for post-operative upper airwair obstruction Care must be taken to prevent patients in steep head down positions form slipping cephalad on the surgical table Shoulder braces are not recommended

16. Head up tilt is often employed to facilitate upper abdominal surgeries. The position of head above the heart reduces cerebral perfusion pressure and may also cause systemic hypotension as venous return decreases REVERSE TRENDELENBURG POSITION

17. Greatest concerns are circulation and pressure points. Most common nerve damages: Brachial plexus: arm abduction >90 degrees . Radial and ulnar: compression against the OR bed, metal attachments 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, calcaneus) SUPINE CONCERNS

18. Pressure alopecia Caused by ischemic hair follicles, us related to prolonged immobilization of the head with its full weight falling on a limited area, usually the occiput. Backache May occur because the normal lordotic curvature is often lost during GA with muscle relaxation or a neuraxial block Peripheral nerve injury Brachial plexus injury, ulnar neuropathy, etc. COMPLICATIONS

19. LITHOTOMY POSITION

20. 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. The knees are flexed until the lower legs are parallel to the torso and supports or stirrups hold the legs. The foot section of the table is lowered or detached POSITION

21. The lower extremities should be padded to prevent compression against the stirrups I nitiation of the lithotomy position requires coordinated positioning of the lower extremities by two assistant to avoid torsion of the lumbar spine. Both the legs should braised together, simultaneously flexing the hips and knees After the surgery, the patient must also be returned to the same position in a coordinated manner

22. The recommended position of the arms is on armrests far from the table hinge point. If the arms are on the surgical table alongside the patient, then the hands and fingers may lie near the open edge of the lower section of the table. Crush injury of fingers may occur when the foot of the table is raised. ARM POSITIONING

23. Frequently used for procedures that requires a vaginal or perineal approach The patient is in the supine position with legs raised and abducted by stirrups Once the feet are positioned in the stirrups, the foot-board is removed and the bottom section of the bed is lowered. HIGH LITHOTOMY POSITION

24. All the positioning techniques used in high lithotomy apply. Placed in supine position with the legs raised and abducted in crutch-like or full lower leg support stirrups. The angle between the patient’s thigh and trunk is not as acute as for the high lithotomy position Used in vaginal procedures, perineal access, transurethral instrumentation. LOW LITHOTOMY POSITION

25. Transperineal access to the retropubic area The patient’s pelvis is flexed ventrally on the spine The thighs almost forcibly flexed on the trunk The lower legs aimed skyward so they are out of the way The long axis of the symphysis pubis almost parallel to the floor EXAGGERATED LITHOTOMY POSITION

26. STIRRUPS

27. When the legs are elevated, venous return increases, causing a transient increase in cardiac output, central venous, intracranial pressure in otherwise healthy patients The lithotomy position causes the abdominal visceral to displace the diaphragm cephalad, reducing lung compliance and tidal volume The normal lordotic curvature of the lumbar spine is lost, potentially aggravating any previous lower back pain. LITHOTOMY CONCERNS

28. POTENTIAL NERVE INJURIES

29. Rare complication caused by inadequate tissues perfusion that is associated with the lithotomy position Local arterial pressure decreases 0.78 mmHg for each cm the leg is raised above the right atrium Decompression fasciotomy -tissue pressure >30 mmHg Irreversibel muscle damage - pressure >50 mmHg Long surgery time is a distinguishing characteristic associated with this COMPARTMENT SYNDROME

30. LATERAL POSITION

31. The lateral decubitus position mostly used for surgery involving the thorax, retro peritoneal structures, or hip, or in one lung ventilation method The patient rests on the non operative side and is balanced with anterior and posterior support (bedding rolls, inflatable bean bag) The patient’s head must be kept in a neutral position to prevent excessive lateral rotation of the neck and stretch injuries to brachial plexus. LATERAL DECUBITUS POSITION

32. Rolled laterally to thte non-operative site Lower leg is flexed with padding in between the legs, and both arms are supported and padded Dependent ear should be checked to avoid folding and undue pressure Eyes should be securely taped closed before repositioning and frequently checked for compression Kidney rest must be properly placed under the dependent iliac crest to prevent compression of the inferior vena cava. POSITIONING AND SUPPORTS

33. To avoid compression to the dependent brachial plexus or blood vessels, an axillary roll is placed between the chest wall and the bed. Pulse should be monitored in the dependent arm for early detection of the axillary neurovascular compression

34. Patient may be flexed in lateral position To spread the ribs during thoracotomies To improve exposure of the retroperitoneum for renal surgeries The point of flexion should lie under the iliac crest rather than under the flank or lower ribs to optimized ventilation of the dependent lung FLEXED LATERAL DECUBITUS POSITION

35. PRONE POSITION

36. The prone or ventral decubitus position is primarily used for surgical access to the posterior fossa of the skull, the posterior spine, the buttocks, perirectal area and the lower extremities Patient’s legs should be padded and flexed slightly at the knee and hip Arms may be tucked sidewise neytrally or on the armboard next to the head The head supported facedown or turned to the side POSITIONING

37. When GA is planned, the patient is first intubated on the stretcher. The tube is well secured to prevent dislodgement. Wire-reinforced tube is considered With the coordination of the entire operating room staff, the patient is turned prone into the OR table, keeping the neck in line with the spine during the move Extra padding under the elbow is needed to prevent compromise of the ulnar nerve

38. CAREFUL PRONE POSITIONING

39. Mayfield (Pin) Head holder It supports the head without any direct pressure on the face These pins allow access to the airway and firmly hold the head in one position that can be finely adjusted for optimal neurosurgical exposure Rigid fixation is provided for cervical spine and posterior intracranial surgery Extreme head positions may increase the risk of cervical cord injury POSITIONING AIDS AND SUPPORTS

40. Horseshoe head rest It supports only the forehead and the malar regions. Allows excellent access to the airway and eyes. The face is seen from below Head height is adjusted to position the neck in a natural position This head rest is rigid and therefore potentially dangerous if the head moves. POSITIONING AIDS AND SUPPORTS

41. Mirror System Bony structures of the head and face are well supported Monitoring of the eyes and airway is facilitated with a plastic mirror The eyes should be taped closed POSITIONING AIDS AND SUPPORTS

42. Arms are abducted less than 90 degrees The chest and abdomen are supported away to the bed to minimize abdominal pressure to preserve pulmonary compliance Soft head pillows has cutouts for eyes and nose Breasts and genitalia should be free from torsion To promote low abdominal and thoracic pressure, multiple paddings and rolls are put in place PRONE POSITION WITH WILSON FRAME

43. Because the abdominal wall is easily displaced, external pressure on the abdomen may elevate intra abdominal pressure External pressure on the abdomen may push the diaphragm cephalad, decreasing FRC, pulmonary compliance and increasing peak airway pressure. Careful attention must be paid to the ability of the abdomen to hang free and to move with respiration Abdominal pressure also may impede venous return through compression of the inferior vena cava. PRONE CONCERNS

44. AIRWAY Accidental extubation Obstruction of ET tube Facial,airway edema NECK INJURY Excessive lateral torsion or hyper flexion leads to post operative pain, cervical nerve root or vascular compression Accentuation of pre-existing trauma VISUAL LOSS COMPLICATIONS

45. Used for anal surgeries , pilonidal excision. Places patient prone with head & feet at a lower level The hips are over the center break of the OR bed between the body and leg sections Chest rolls are placed to raise the chest JACK KNIFE POSITION

46. Exaggerated Jack knife position Used for sigmoidoscopy, lumbar laminectomy Severe hypotension can happen due to pooling of blood in lower limb KNEE CHEST POSITION

47. SITTING POSITION

48. The sitting position is preferred in approaching the posterior cervical spine and the posterior fossa The head may be fixed in pins or taped in with adequate support Arms must be supported to prevent shoulder traction and stretching of the brachial plexus The knees are slightly flexed for balance and to reduce stretching The legs are kept as high as possible to promote venous return Position produces excellent surgical exposure, decrease blood in the operating field, superior access to the airway, reduces facial swelling. POSITIONING

49. Used for shoulder surgeries, including arthroscopic procedures The arms must be supported to prevent stretching of the brachial plexus without pressure on the ulnar area of the elbow. Associated with neurologic injury, cervical neurapraxia and hypotensive bradycardia BEACH CHAIR POSITION

50. Because of the pooling of blood into the lower body, patients under GA are prone to hypotensive episodes Excessive cervical flexion can impede arterial and venous blood flow, causing hypoperfusion or venous congestion of the brain Because of the elevation of the surgical field above the heart, and inability of the dura venous sinuses to collapse because of their bony attachment, they risk of venous air embolism is a constant concern SITTING CONCERNS

51. Venous air embolism Hypotension Airway obstruction Macroglossia Pneumocephalus quadriplegia COMPLICATIONS

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