• Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off
Reading...
Front

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key

image

Play button

image

Play button

image

Progress

1/21

Click to flip

21 Cards in this Set

  • Front
  • Back
SO20 ANZCA Version [Mar 06] Q98 [Jul06] Q53

In anaesthetised patients undergoing controlled ventilation, release of a lower-limb arterial
tourniquet after sixty minutes will

A. cause no change in end-tidal CO2 tension

B. decrease central venous pressure for more than 30 minutes before returning to baseline

C. decrease oxygen consumption

D. increase cerebral blood flow

E. increase core body temperature transiently
ANSWER D

SPECIFICATIONS
• cuff should be > 40% circumference of limb
• minimal inflation pressure to prevent arterial flow = systolic + 50mmHg (upper limb) and usually 2 x systolic pressure in lower limb
• limit to shortest time possible with an upper limit of 2 hours in healthy patients
• for surgical procedures longer than 2 hours, the torniquet should be deflated every 2 hours to allow 10min of reperfusion of the muscles beneath and distal to the cuff


CONSEQUENCES

SYSTEMIC

Cardiovascular
• increased venous return and cardiac output (lower limb exanguination can result in 400ml transfusion)
• hypertensive response to pain
• hypotension resulting from release of ischaemic mediators and shift of blood volume back into the limb
• effects are minimal in healthy patients but may not be tolerated by patients with poor cardiac function

Respiratory
• increased ET CO2 on release of torniquet necessitating an increase in minute ventilation

Cerebral
• rapid increase in CO2 after deflation of the torniquet is associated with a 50% increase in MCA blood flow that peaks at 2 – 4 mins and may contribute to brain injury in patients with increased ICP

Haematological
• overall inflation of a torniquet and surgical pain may result in:
- systemic hypercoagubility
- deflation may result in short lived increase in thrombotic activity in peripheral blood

• risk of precipitating a sickle cell crisis in patients with sickle cell disease

Temperature
• reduced heat redistribution from central to peripheral compartment and decreased heat loss from distal skin and therefore lower heat loss during period of inflation
• torniquet deflation results in increased redistributive loss

Metabolic
• production of ischaemic mediators including CO2, lactate and K+ which may result in:
- increased serum K+ by approximately 0.2mmol/L and peaks at 3 mins
- increased serum lactate by ~ 2mmol/L and remains elevated for 30 mins
- decrease in pH due to CO2 and Lactate (maximal decrease at 4 mins)
• increased oxygen consumption and CO2 production after release
• above changes are dependent on duration of torniquet inflation


LOCAL EFFECTS
Nerve
• upper limb more prone to nerve injury than the lower limb (radial nerve most vulnerable, sciatic nerve usually involved in the lower limb)
• causes include:
- mechanical pressure
- ischaemic injury

** in general nerves are most susceptible to mechanical pressure and muscles to prolonged ischaemia**

Muscle
• muscle injury tends to be greatest just below the torniquet due to a combination of mechanical deformation and ischaemia
• ‘post torniquet syndrome’ caused by a combination of muscle ischaemia, oedema and microvascular conjestion
• minimised by use of lower inflation pressure

Vascular
• arterial injury uncommon and mostly occurs in patients with peripheral vascular disease - mechanical pressure can traumatise atheromatous vessells causing plaque fracture

Skin
• pressure necrosis or friction burns
• chemical burns caused by skin preparation solutions that seep beneath the torniquet and are held against the skin under pressure

Pain
• classically very difficult pain to treat and may be unresponsive to systemic analgesics or deep anaesthesia
• transmitted by unmyelinated C fibres
• can occur during spinal or epidural anaesthesia despite adequate sensory anaesthesia because the larger nerve fibres carrying pressure-pain sensation may not be blocked due to inadequate concentration of local anaesthetic

REFERENCES
‘The arterial Torniquet’ Anaesthesia 2001 Kam
SO16 ANZCA version [2005-Apr] Q134 [2006-Mar] Q67

The leading cause of perioperative death in hip arthroplasty surgery is

A. blood loss

B. bone cement implantation syndrome

C. myocardial infarction

D. pneumonia

E. pulmonary embolus
ANSWER C
SO17 ANZCA version [2005-Sep] Q104, [Mar06] Q78, [Jul07]

Each of the following statements concerning surgery for correction of scoliosis is true EXCEPT

A. one third of the blood loss occurs postoperatively

B. major blood loss is frequently accompanied by a consumptive coagulopathy

C. surgery will halt progression of the restrictive lung deficit

D. the major neurological deficits that occur are usually due to damage to the posterior columns of the spinal cord

E. the use of aprotinin reduces blood loss
ANSWER D

* A. one third of the blood loss occurs postoperatively - true
o "About a third of the blood loss occurs in the postoperative period." (Gibson PR. Anaesthesia for correction of scoliosis in children. Anaesth Intensive Care. 2004 Aug;32(4):548-59)[1] (http://www.aaic.net.au/pdf/2003512.pdf)
* B. major blood loss is frequently accompanied by a consumptive coagulopathy - true
o "The coagulopathy is both dilutional and consumptive55, and also related to the length of procedure and number of segments fused."
* C. surgery will halt progression of the restrictive lung deficit - true:
o "For scoliosis secondary to neuromuscular disease, surgery may be indicated to improve wheelchair posture and aid nursing care as well as to prevent progression of restrictive lung defect in patients with already compromised respiratory function."
* D. the major neurological deficits that occur are usually due to damage to the posterior columns of the spinal cord - false and answer to choose:
o Neurological injury can be due to:

1.
1. 1) direct contusion of the cord by implant or instrument.
2. 2) reduction of spinal cord blood flow by stretching or compression of vessels or direct interruption of radicular blood flow.
3. 3) distraction injury of the spinal cord
4. 4) epidural haematoma.

* E. the use of aprotinin reduces blood loss - true:
o "Antifibrinolytics have been shown to reduce blood loss during scoliosis surgery, particularly in patients with neuromuscular disease59-62. The serine protease inhibitor aprotinin is the most studied and the most effective, halving blood loss in high-risk patients."
SO18 ANZCA Version [Jul06] Q110 April 07 Q78

A previously healthy 20-year-old male is undergoing open reduction and internal fixation of a fractured tibia. The limb was exsanguinated and the tourniquet appropriately applied and inflated to 250 mmHg prior to surgery. A small amount of continued bleeding is noted after surgical exposure. The tourniquet still seems appropriately inflated. The patient's blood pressure is 110/70 mmHg. You should

A. accept that a tourniquets does not stop all bleeding

B. check the patient's coagulation profile

C. inflate the tourniquet to a higher pressure

D. reduce the patient's blood pressure

E. re-exsanguinate the limb and re-apply the tourniquet
ANSWER A

Intraoperative bleeding may be caused by:

* An underpressurized cuff. Underinflation of the tourniquet cuff can result in venous pooling, leading to passive venous congestion of the limb, hemorrhagic infiltration of the nerve, and oozing of blood into the field.
* Blood remaining in the limb because of insufficient exsanguination.
* Too - slow inflation and deflation, both of which allow arterial flow to enter while preventing venous return.
* Improper selection of the cuff, resulting in a poor or loose fit.
* Excessive padding between the cuff and the limb, which prevents a snug fit.
* A cuff that is applied too loosely.
* Blood entering through the intramedullary nutrient vessels of the long bones (such as the humerus). Theoretically, if breakthrough arterial bleeding does occur, it does so less often than the venous ooze due to medullary cavity bypass of venous blood.
SO19 [Apr07] Q119

A well 65 year old is having a THR under general anaesthesia with sevo/N2O/fentanyl. BP is 130/70. Before the surgeon commences reaming and cementing, the best thing to do is:

A. Induce hypotension

B. Raise BP with vasopressors

C. Turn off nitrous

D. Give steroids

E. Give heparin 5000u
ANSWER C

CEMENT SYNDOME / FAT EMBOLI

DEFINITIONS

• Fat embolism:
Presence of fat globules in the lung parenchyma and peripheral circulation after long bone or other major trauma

• Fat embolism syndrome:
Distinct pattern of clinical symptoms and signs following fat emboli,
- more frequent in closed fractures
- mostly associated with fractures of long bones
- overall mortality 5 – 15%
- typically presents 24 – 72 hours post injury
- classic triad: respiratory changes, neurological abnormalities, petechial rash
- other clinical features include pyrexia, tachycardia, right heart strain, coagulopathy & renal changes

• Bone cement implantation syndrome:
No agreed definition. Characterised by hypoxia, hypotension, arrhythmias, increased PVR & cardiac arrest. Fat embolism seems to be the most likely aetiology


PATHOLOGY
Fat from disrupted bone marrow is forced into torn venules

Bone cement implantation syndrome:
? release of methylmethacralate into the circulation during cementation
? role of emboli formed during cementing and prosthesis insertion (emboli include fat, cement particles, air, bone and aggregates of plaletes and fibrin)
fat embolism seems the most likely aetiology


RISK FACTORS FOR BONE CEMENT IMPLANTATION SYNDROME
Patient:
- metastatic disease/pathological fracture
- old age
- pre-existing pulmonary hypertension

Surgical:
- un-instrumented femoral canal (redo surgery less likely)
- inter-trocanteric fracture
- long stem arthroplasty


PREVENTION
• early immobilisation of fractures
• operative correction of fractures
• surgical options:
- limit intraosseous pressure during orthopaedic procedures
- venting hole to limit intraoperative rises in intraosseous pressure (i.e vent b/w lesser & greater trocanter)
- use of cementless prosthesis
- unreamed intramedullary femoral shaft
Anaesthetic implications
- increase FiO2 at time of cementation
- avoid intravascular volume depletion – ensure adequate blood volume prior to cementing
- stop nitrous
- measure BP frequently during this time

DETECTION
• fall in end tidal CO2 concentration (usually first sign)
• dyspnoea (in awake patient under regional)
MANAGEMENT
• 100% oxygen
• cardiovascular collapse in the context of BCIS should be treated as RV failure
- aggressive treatment with fluids
- inotropes (with emphasis on directly acting alpha agonists)
SO21 [Jul07] Q129

Acute compartment syndrome in the lower limb

A. can be reliably detected by loss of peripheral pulses

B. does NOT occur after open fractures of the tibia

C. is a contraindication to regional anaesthesia

D. is often associated with pain on passive stretching of the affected compartment

E. occurs more commonly in patients over 35 years of age
ANSWER C

Arises when circulation and tissues within a closed space are compromised by increased pressure.

Characterised by
1. ischemia
2. necrosis
3. loss of function

Sign and symptoms
1. Pain mainly over the affected compartment, worsened by passive stretching of the muscles
2. Tense swelling over the compartment
3. Paraesthesia in the distribution of nerves transversing the compartment
4. Distal pulses are usually present
SO22 ANZCA version [Apr08] Q132

A tourniquet is being used on the arm of an adult patient to reduce haemorrhage during surgery on the
hand. The maximum recommended time to leave the tourniquet continuously inflated is:

A. 60 minutes

B. 90 minutes

C. 120 minutes

D. 150 minutes

E. 180 minutes
ANSWER C
ANZCA Version [Apr08]

A 20-year-old, 80 kg, previously well male is awaiting surgery for a fractured femur. He was admitted 12 hours earlier following a motor-bike accident. His admission chest X-ray was normal. Since admission, analgesia has been provided with a femoral nerve block and 40 mg of intravenous morphine. He has been placed in leg traction. He is now drowsy and confused. His blood pressure is 120/70mmHg, pulse 120 min-1 and respiratory rate 25 min-1. On auscultation of the chest, inspiratory crepitations can be heard. Despite supplemental oxygen of 6 1.min-1 via Hudson mask his arterial oxygen saturation (SaO2) is 85%. The most likely cause of the low SaO2 is:

A. Aspiration

B. fat embolism syndrome

C. hypoventilation

D. pneumothorax

E. pulmonary contusions
ANSWER B
Black Bank March 2010

65.Text Re: Trauma pt, Head Injury GCS 5, high ICPs, best management for ortho procedure(repeat)

A. Propofol/fentanyl

B. Propofol / nitrous

C. Other options with volatiles
ANSWER A

Prop/Remi is a better answer
SO15 ANZCA version [2002-Aug] Q79, [2004-Apr] Q20, [2004-Aug] Q11, [2005-Sep] Q29

The single most important treatment in preventing acute renal failure following crush injury is

A. maintenance of an alkaline urine (pH > 6) to prevent cast formation

B. maintenance of adequate urine output with mannitol

C. vigourous intravenous fluid replacement

D. administration of xanthine oxidase inhibitors to prevent hyperuricemia

E. emergent dialysis to remove myoglobin from the circulation
ANSWER C

Treatment focuses on preventing myoglobin precipitation in the urine by maintaining a brisk alkaline diuresis.

* Immediately administer saline to patients with volume depletion.
* Follow-up with mannitol to induce diuresis, supported by adequate IV fluids.
* Raising the pH of the urine to 6.5 or more can be facilitated by adding sodium bicarbonate to the fluids.
SO14 [Apr97] [Jul97] [Apr98] (type A)

Fat embolus:

A. 30% mortality

B. Only with orthopaedic injuries

C. Petechial rash from thrombocytopenia

D. 5% incidence with pelvic and long bone fractures

E. Decreased incidence with early fixation of fractures
ANSWER E
SO13 [Aug91] [Mar92] [Aug92]

The commonest organism cultured from septic arthritis (?knee) is:

A. Neisseria gonorrhoea

B. Strep pyogenes

C. Staph aureus

D. Staph epidermidis

E. E. coli
ANSWER C
SO12 [Aug96] [Jul97] [Apr99] [Aug99]

Meralgia paraesthetica is relieved by nerve block of the:

A. Lingual nerve

B. Trigeminal nerve

C. Lateral femoral cutaneous nerve

D. Lumbar sympathetic chain

E. Femoral nerve
ANSWER C
SO11 ANZCA version [2002-Aug] Q18, [2003-Apr] Q4

Following nerve injury involving

A. axonotmesis, full recovery of function of the nerve can be expected in a few days

B. neurapraxia, regrowth of the axon occurs from the node of Ranvier proximal to the injury

C. neurotmesis, full functional recovery is very unlikely

D. complete severance, the affected muscles no longer respond to any form of electrical stimulation

E. the division of a nerve in a contaminated wound, immediate suture is essential
ANSWER

'"Early management of nerve injuries

* ABCs as with any injury
* Open wound with nerve injury- thorough debridement. If wound adequately clean and general state of the patient allows, then immediate primary nerve repair is preferred
* Open wound but patients general state in danger. Clean wound and dress with moist dressing, attempt repair at 3-7 days
* Contaminated wounds- Thorough debridement, mark ends of nerve with a suture and consider suturing to soft tisssue to avoid retraction. Repair the nerve when the soft tissues have healed at 3-6 weeks post injury"


* Neurotmesis: transection. The closer it is to the cell body, the more likely that cell death will occur.
* Axonotmesis: wallerian degeneration and recovery, partial. Regrowth of axon comes from proximal end.
* Neuropraxia involves focal demyelination.
* Delayed suture can be performed but the ends should be marked with an epineural suture for correct orientation when they go back
SO06b ANZCA version [2002-Mar] Q144, [2002-Aug] Q145

A forty year old carpenter falls three metres from a ladder onto his left leg. He complains of shooting pains down his left leg when walking and aching pain over his lower back. A diagnosis of L5-S1 nerve root compression on the left would be supported by

1. straight leg raising limited to 40 degrees from supine on the left

2. weakness of toe dorsiflexion

3. depressed Achilles' tendon reflex on the left, compared to the right

4. diminished sensation over the medial aspect of the left calf and ankle
ANSWER 1, 2, 3
SO05 ANZCA version [1988] [Mar93] [2002-Aug] Q9, [2003-Apr] Q6, [2005-Sep] Q31 [Mar06] Q5

A patient with a central dislocation of the hip following a motor car accident
is noted to be shocked on admission, one hour after the accident. The most likely cause is

A. Ruptured bladder

B. Fat embolism

C. Ruptured urethra

D. Neurogenic shock

E. None of the above
ANSWER E
SO04

The sign causing the most concern in a patient with fat embolism is:

A. Dyspnoea

B. Fat globules in the urine

C. Confusion

D. Petechial rash over the upper chest and shoulders

E. Fat in sputum

F. None of the above
ANSWER A and C
SO03

A 13 year old injures his leg at football, presents three weeks later with
a painful lump on the medial aspect of the lower end of the femur. Xray shows
elevated periosteum and some new bone formation. The most probable diagnosis is:

A. Osteochondroma

B. Osteosarcoma

C. Osteoclastoma

D. Haematoma

E. Osteomyelitis
ANSWER B
SO02 [1985] [1986] [1987]

A 12 year old presents having knocked his knee 3 weeks ago and now has a painful knee. An xray shows the periosteal lifting with irregular bone growth under the periosteum. The diagnosis is:

A. Osteomyelitis

B. Osteogenic sarcoma

C. Osteogenesis imperfecta

D. Bony metatases

E. Haemophilia
ANSWER B
SO01

A 24 year old male is admitted to hospital with facial and scalp lacerations,
and fractured femur following a motor vehicle accident. On the second day he
becomes restless, confused, tachypnoeic with an oral temperature of 38C. The
most likely diagnosis is:

A. Delayed concussion

B. Fat emboli syndrome

C. Secondary haemorrhage

D. Pneumonia

E. Pneumothorax
ANSWER B
TMP-115 [Mar10]

Patient for total knee replacement under spinal anaesthetic. Continous femoral nerve catheter put in for post op pain relief. Good analgesia and range of motion 18hrs post op. At 24hrs post op, patchy decreased sensation in leg and unable flex knee.

What is the cause?

A. Compression neurapraxia (i think it said due to torniquet)

B. DVT

C. Muscle ischaemia

D. Damage to femoral nerve

E. Spinal cord damage.
ANSWER A