positioning.ppt
- 1. Presented by Dr.Samita S Khan Consultant Anesthetist SMBB Trauma Center Patient Positioning During Anesthesia & Its Complications
- 2. Objectives • Goals of proper positioning • Preoperative assessment and history • Types of Surgical positions • Practical considerations • Systemic effects of each position • Injuries and hazards of each position
- 3. __ _________ __ _____ __________ Provides optimal exposure of the surgical site Airway management and ventilation (FRC) Provide physiologic safety (BP) Maintenance of the patient’s temperature and dignity by controlling unnecessary exposure. Maintain body alignment & prevent nerve, vessel & soft tissue injury Minimise risk VTE
- 4. Patient Transfer from Bed to Operating Table Friction burns when moving, Avoid Pressure on soft tissues, vessels & nerves and ears with appropriate padding Avoid Contact with metal Avoid Leaning on patient Avoid Eyes from extra-ocular pressure and close lids to prevent corneal abrasions Protect Pt position relative to table “breaks” Note Any physical abnormalities & avoid hyperextension of joints Consider Pt tolerance to position (including length of op & type of anaesthesia) Consider
- 6. PREOPERATIVE ASSESSMENT AND HISTORY In the preop clinic these attributes should be considered and documented which might result in injury during positioning in surgery Obesity Poor nutritional status. Advanced age (e.g., age 70 or older). Preexisting conditions (e.g., arthritis, diabetes, hypertension,hypotension, immunodeficiency, neurologic conditions, peripheral vascular disease, respiratory conditions). History of skin breakdown or pressure ulcers. History of smoking
- 7. Types of surgical positions DORSAL DECUBITUS SUPINE LITHOTOMY HEAD DOWN TILT TRENDELENBURG REVERSE TRENDELENBURG LATERAL DECUBITUS HORIZONTAL LATERAL LATERAL JACK KNIFE KIDNEY VENTRAL DEUBITUS FULL PRONE PRONE JACKKNIFE KNEELING SITTING or FOWLERS POSITION
- 8. SUPINE POSITION Physiologic effects of change from vertical to horizontal position Cardiac output ↑ on assuming supine position Venous blood from lower body ↓ flows back To heart ↓ Stretches atrial wall ↓ (Laplace’s law) Stroke volume ↑ ↓ ↑ blood pressure (clinically normal BP observed)
- 9. Baroreceptors in Aorta Baroreceptors in Carotid Sinus ↓ via ↓ via Vagus nerve Glossopharyngeal nerve Medulla Oblongata ↓ efferent ↑ Parasympathetic activity
- 10. Changes in respiratory physiology • increase in pulmonary blood volume therefore improved diffusing capacity • Decrease FRC due to push of diaphragm superiorly by abdominal contents(500- 1000ml) • Decreased anatomical dead space by a third
- 13. PRACTICE ESSENTIALS Supine:METHOD Horizontal:The arms are padded and restrained along side the trunk or abducted on padded arm boards Contoured:The arms are placed a for the horizontal position ;the knees and hips are slightly flexed POINTS TO REMEMBER: The ulnar nerve is the most frequently injured nerve in the perioperative period. It's theorized that damage occurs secondary to compression of the nerve at the level of the elbow
- 14. Contd.. supination of the patient's forearm,and padding of the elbow helps minimize it. Patient’s arm should never be abducted greater than 90 degrees. Extending the arms further than this can stretch and injure the brachial plexus. The patient shouldn't have his legs crossed because this may cause pressure on the sural nerve of the upper leg and the peroneal nerve of the lower leg. His knees and hips should be slightly flexed to reduce stress on the back and abdomen.
- 15. Axillary trauma from the humeral head abduction of the arm on an arm board to >90 degrees may thrust the head of the humerus into the axillary neurovascular bundle) Radial nerve compression a vertical bar of screen forces the nerve against the humerus; wrist drop.
- 16. LITHOTOMY • Used in Urology(TURP/TURBT), gynaecology or AP excision rectum or proctology • Patient is moved to the lower end of the table with the legs supported by an assistant. • ASIS at the level of the break of the table & end removed • Avoid overhanging buttocks at the end of the table. • The lower back should be supported to maintain normal lumbar lordosis. • Arms should be positioned on arm boards at less than 90 degrees or over the abdomen. • Flex knees & hips <90 degrees (to protect the sciatic, femoral & obturator nerves) • At the beginning and end of surgery the patient’s legs must be moved simultaneously and with care to prevent pelvic injury and sudden hypotension. • Legs are placed outside of the lithotomy poles to avoid pressure on the common peroneal nerve. • Stirrups should be placed at an even height. • Knees & ankles should be padded to prevent pressure and contact with a metal surface.
- 17. step1
- 18. STEP 2
- 19. STEP3
- 20. LITHOTOMY Issues/Risks- esp with prolonged surgery > 2hrs Compartment Syndrome Note time of surgery starting consider resting legs for 10 mins every 2 hrs Note any suggestive signs and Sx post operatively Nerve injury Obstruction to venous drainage- need DVT prophylaxis Increased central venous return on leg elevation & hypotension when put back down
- 22. Peroneal nerve injury: Pressure of head of fibula by bar or support structures compresses nerve Saphenous nerve injury: Pressure on medial condyle of tibia compress nerve Femoral nerve injury: Due to angulation of thigh such that inguinal ligament is stretched & compresses nerve Obturator nerve injury: Due to greater degree of thigh flexion there is stretching of nerve as it exits the obturator foramen
- 23. COMPARTMENT SYNDROME Long duration of lithotomy position Tightening of leg straps Dorsi-flexion of ankle Surgeon leaning on suspended leg for long duration Characterized by systemic hypotention and impaired perfusion pressure to the legs that is augmented by elevation of the extremities,decompressive fasciotomies are necessary to release tissue pressure.
- 24. LATERAL POSITION Usually positioned with bean bag or position supports. Head must be aligned to support the spinal column and prevent compression of dependent arm. Pillows placed between legs and feet Bottom leg flexed to provide stability and facilitate venous drainage. Peroneal nerve susceptible to injury
- 25. Kidney rest- beneath the bony iliac crest, not under fleshy waist area Axillary rolls- placed at scapula near the axillary space to relieve pressure on the arm and foster adequate chest excursion. Dependent shoulder, axilla, and deltoid must be padded. Lower arm brought forward to prevent pressure on brachial plexus.
- 28. – Compression of vena cava with kidney rest – Dependent lung is underventilated-pressure of abdominal contents and wt of mediastinum. – Nondependent lung is overventilated because of increased compliance. – Blood flows to underventilated lung by gravity. – V/Q mismatch may manifest as hypoxemia ANESTHETIC CONCERNS
- 30. Trendelenburg position • Modification of supine position • Places head down along with the whole body • Advantages of this position: – Moves viscera cephalad – Helpful in lower abdominal surgeries – To ↑ central blood volume to facilitate central vein cannulation – To minimize aspiration during regurgitation
- 31. ↑ CVP ↑ ICP ↑ IOP ↑ myocardial work ↑ pulmonary venous pressure ↓ pulmonary compliance ↓ FRC Swelling of face, eyelids, conjunctiva & tongue observed in long surgeries EFFECTS OF TRENDELENBURG POSITION
- 33. Reverse trendelenburg position This is the opposite of Trendelenberg’s position This position places head end up & feet down This position helps in caudal movement of abdominal contents Used in upper abdominal laparoscopic surgeries – Lap gastric banding Causes venous pooling in lower limbs To prevent DVT stockings is a must
- 34. PRONE Physiological changes • The most important feature of turning a patient prone under anaesthesia is a drop in cardiac output. • compression of the inferior vena cava (IVC) reducing venous return to the heart. When the IVC is itself obstructed, blood uses a collateral return route – the vertebral wall venous plexuses. • As prone positioning is often used for spinal surgery, this can cause increased bleeding in the surgical field. It is important to decrease the pressure on the abdomen directly – this can be achieved with specially designed operating tables, or by placing wedges under the chest and pelvis
- 35. Respiratory system • Functional residual capacity and arterial oxygen tension both increase. • The exact reason for this improved function is unclear, although it is most likely that changes in ventilation and perfusion result in better V/Q matching, and thus improved arterial oxygen tension.
- 36. Careful positioning from supine position Prevent pressure on abdomen Prevent pressure on eyes Pillows to rest the lower limbs Prevent pressure on male external genitalia PRONE POSITION
- 37. Prone position
- 38. Prone position
- 39. COMPLICATIONS OF PRONE POSITION o Eye and ear injuries are more common in this position. Scleral edema is common in prone patients oThoracic outlet syndrome (TOS) is a syndrome involving compression at the superior thoracic outlet resulting from excess pressure placed on a neurovascular bundle
- 41. MORE COMPLICATIONS o Blindness: Permanent loss of vision can occur after nonocular surgical procedures especially in patient in the prone position oBlood loss hypotension and anemia may all conspire together to produce optic nerve ischemia.
- 42. Other prone positions Jackknife position 42
- 44. Sitting position:fowlers position For posterior cranial fossa position • Better surgical exposure • Less tissue retraction & damage • Less bleeding • Less cranial nerve damage • More complete resection of lesion • Ready access to airway, chest & extremities • Modern monitoring gives early warning of venous air-embolism
- 46. COMPLICATIONS OF SITTING POSITION Postural hypotension Air embolus (the potential increases with the degree of elevation or the operative site above the heart; air may pass through a probe patent foramen ovale if right atrial pressure exceeds left atrial pressure) Pneumocephalus Ocular compression Edema of the face and tongue Sciatic nerve injury
- 47. Summary of American Society of Anesthesiologists'Advisory on Prevention of Peripheral Neuropathies Upper Extremity Positioning •Arm abduction should be limited to 90 degrees in supine patients. •The arms should be positioned to decrease pressure on the postcondylar groove of the humerus
- 48. Contd.. Lower Extremity Positioning Lithotomy positions may stretch the sciatic nerve. Prolonged pressure on the peroneal nerve at the fibular head should be avoided. Protective Padding Padded arm boards may decrease the risk of upper extremity neuropathy. Padding at the elbow and fibular head may decrease the risk of neuropathies
- 49. Contd… Equipment Properly functioning automatic blood pressure cuffs on the upper arms do not affect the risk of neuropathies. Postoperative Assessment Assessment of extremity nerve function may lead to early recognition of peripheral neuropathies. Documentation Charting specific positioning actions during patient care may result in improvement in care.