Wednesday, June 29, 2011
CHADS2
Tuesday, June 28, 2011
epidural abscess
Bier's block
Interscalene
superficial cervical plexus block
Monday, June 27, 2011
trauma- neck.subcut emphysema
(May-2001 Q10) A 17 yo trail bike rider was struck on the neck by a low branch and thrown from his bike. He presents to your casualty with a hoarse voice, stridor and subcutaneous emphysema of the neck. Discuss your plan to secure this patient's airway.
This patient has a history of neck trauma and impending respiratory distress. In view of the history of neck trauma and subcutaneous emphysema, the most important differential will be disruption of the tracheobronchial tree.
I would consult an ENT specialist with view of performing a surgical airway, as it is likely that any upper airway manipulation might be difficult in view of localized trauma, and the disruption might be distal to the glottis.
I would discuss with the patient regarding an awake tracheostomy under local anaesthesia. This would be done with supplemental O2 via facemask and standard college monitoring is in place.This may not be tolerated well by the patient, however sedation may be fraught with danger because he might have respiratory depression that would further compromise the airway.
maintain spont vent
Alternatives would be fibre optic assessment of the trachea but this is not ideal in this situation given that the patient is stridorous and less likely to cooperate with the procedure. Also, any trauma or bleeding from fibre optic intubation may further jeopardise the airway.
any ETT should be cuffed passed distal to the disruption
Tracheostomy -may be able to locate the distal end of the disruption but may still be proximal to the tracheobronchial disruption , may be difficult due to local tissue injury/bleeding/ edema, may not be aseptic.
After securing the airway, secondary survey looking for other causes of subcut emphysema/ other areas of injury
definitive imaging: neck XR/CT thorax
novoseven Control trial
Results of the CONTROL Trial: Efficacy and Safety of Recombinant Activated Factor VII in the Management of Refractory Traumatic Hemorrhage
C Hauser et al. J Trauma. Sept 2010: 69(3); 489-500
Results: Enrollment was terminated at 573 of 1502 planned patients because of unexpected low mortality prompted by futility analysis (10.8% vs. 27.5% planned/predicted) and difficulties consenting and enrolling sicker patients. Mortality was 11.0% (rFVIIa) versus 10.7% (placebo) (p = 0.93, blunt) and 18.2% (rFVIIa) versus 13.2% (placebo) (p = 0.40, penetrating). Blunt trauma rFVIIa patients received (mean ± SD) 7.8 ± 10.6 RBC units and 19.0 ± 27.1 total allogeneic units through 48 hours, and placebo patients received 9.1 ± 11.3 RBC units (p = 0.04) and 23.5 ± 28.0 total allogeneic units (p = 0.04). Thrombotic adverse events were similar across study cohorts.
Conclusions: rFVIIa reduced blood product use but did not affect mortality compared with placebo. Modern evidence-based trauma lowers mortality, paradoxically making outcomes studies increasingly difficult.
Sunday, June 26, 2011
paeds dental
Thursday, June 23, 2011
severe preeclampsia
(Oct-2008 Q8) A 25yo primigravida patient presents to the delivery suite at 38 weeks gestation complaining of a headache and difficulty with her vision. Her BP is 180/115 and she has clonus. CTG monitoring shows no indications of foetal distress. Outline your initial management of her pre-eclampsia
Wednesday, June 22, 2011
reimplanted limb
(May-2007 Q14) An otherwise fit 30 yr old man is having microvascular reimplantation of his forearm. Describe methods available to optimise the perfusion of the perfusion of the reimplanted limb in the post-operative period.
Pharmacological :
1) regional anaesthesia induced sympatholysis and vasodilation of upper limb arterioles
2) dextran: polysaccharide, inhibits , promotes microvascular blood flow
Non pharmacological
1) keeping reimplanted limb warm
2) ensuring adequate hydration to avoid increased vasoconstriction and SVR
3) avoiding compartment syndrome, keeping replanted limb elevated
4) optimal Hb
5) appropriate monitoring of BP
6) monitoring of limb, early management of ischaemia
7) ?optimising venous pressure?
Although the question asked for management in the post operative period, no candidate was marked down for discussion involving intra-operative factors affecting post operative management.
Monday, June 20, 2011
drugs for pregnant
Sunday, June 19, 2011
radial art cannulation
(May-2008 Q2) Why is the radial artery a common site for arterial cannulation? What complications may occur from radial artery cannulation and how may they be minimised?
The radial artery is a common site for cannulation because it is superficial and easy to assess, distal and therefore allows more proximal arteries to be left intact in case of failing to cannulate distally, the proximal brachial artery is still available as an alternative (although this is not ideal).
It is compressible and therefore in the case of a hematoma, expansion of the hematoma may be limited by direct pressure
Clean, correlates well with BP, collateral circulation, discrete from nerves
Complications:
1) hematoma
2) thrombosis/ vasospasm/air bubbles leading to distal ischaemia
- minimized if pre cannulation allen’s test is done to ensure presence of collateral circulation to the hands prior to radial art cannulation
3) infection- this may be minimized by using an aseptic technique, vigilance for infection/ cellulitis and prompt removal of the cannula, changing the site of the cannula every week (?evidence?) strict asepsis when obtaining blood samples from cannula
4) Invasive arterial cannulation only when indicated : >4 ABG /day, hemodynamic monitoring crucial
5) Drug injection- adequate labelling, staff training, prompt recognition if drug has been given to do corrective measures
aspiration
(May-2006 Q1) List the predisposing factors for aspiration of gastric contents in a patient undergoing general anaesthesia. Discuss the measures you would take to prevent this complication.
Predisposing factors :
1) patient factors
- GERD
- Pregnancy
- inadequate fasting : 8 hours or more for fatty food, 6 hours for milk or solids, 2 hours clear feeds, 3-4 hours for breast milk in <4 month old infants
- type of food
- medications that slow gastric emptying: opioids
- distracting injuries: trauma
- GI stasis: I/O
2) surgical factors
- laparoscopic surgery
3) anaesthesia factors
- use of a supraglottic device
- gastric insufflation with BV ventilation
- no RSI
altered consciousness/ severe TBI (GCS),
loss of laryngeal reflexes eg stroke/ Parkinson’s
difficult airway
pre op
prevent aspiration
-await gastric emptying if possible
reducing morbidity from aspiration: with reducing volume and acidity : adequate fasting , prokinetics, PPI or antacids/ H2 antagonists
inducing with head up position/shoulder roll/ avoid BVM , intubate with RSI, inflate cuff appropriately
ryles tube to reduce gastric contents
extubate awake
Lower limb block anatomy
Thursday, June 16, 2011
ESRA anticoagulation guidelines
http://www.esra-learning.com/site/generalites/anticoagulation/b_anticoagulation.htm
unfractionated heparin
during low-dose administration of unfractionated heparins, an interval of 4 hours should be observed between heparin administration (usually 5000 IU s.c.) and epidural puncture or catheter removal, in order to avoid bleeding complications. Any repeat administration of low-dose heparin should then follow at the earliest after 1 hour.
risk of haemorrhage after epidural anaesthesia and subsequent heparinization is not increased if the heparinization is carried out at the earliest 1 hour after spinal/epidural puncture and is closely monitored. (and no concurrent antiplatelets)
LMW Heparin
The advantages-high level of bioavailability (ca. 100%) after sc administration and their long half-life of 4–7 hours. Max effect 4hrs post admin
-gold standard for thromboembolism prophylaxis in high-risk patients
-no difference in clinical efficacy has yet been demonstrated between the individual preparations. low risk of HIT but should not be used in patients with HIT
Aspirin
The safety of neuraxial regional anaesthesia in patients receiving acetylsalicylic acid is mainly based on three studies [40–42]. Although the Collaborative Low-dose Aspirin Study in Pregnancy (CLASP)
Wednesday, June 15, 2011
AKI and RIFLE
Acute kidney injury occurred in 67% of intensive care unit admissions, with maximum RIFLE class R, class I and class F in 12%, 27% and 28%, respectively. Of the 1,510 patients (28%) that reached a level of risk, 840 (56%) progressed. Patients with maximum RIFLE class R, class I and class F had hospital mortality rates of 8.8%, 11.4% and 26.3%, respectively, compared with 5.5% for patients without acute kidney injury. Additionally, acute kidney injury (hazard ratio, 1.7; 95% confidence interval, 1.28-2.13; P < 0.001) and maximum RIFLE class I (hazard ratio, 1.4; 95% confidence interval, 1.02-1.88; P = 0.037) and class F (hazard ratio, 2.7; 95% confidence interval, 2.03-3.55; P < 0.001) were associated with hospital mortality after adjusting for multiple covariates.Conclusion: In this general intensive care unit population, acute kidney 'risk, injury, failure', as defined by the newly developed RIFLE classification, is associated with increased hospital mortality and resource use. Patients with RIFLE class R are indeed at high risk of progression to class I or class F. Patients with RIFLE class I or class F incur a significantly increased length of stay and an increased risk of inhospital mortality compared with those who do not progress past class R or those who never develop acute kidney injury, even after adjusting for baseline severity of illness, case mix, race, gender and age.
LA toxicity
The patient has received 20x5mg =100mg of bupivacaine and the weight of the patient is not known here but given the short duration prior to cardiac arrest, the most likely differential in this situation is cardiovascular collapse from LA toxicity. Other less likely differentials would be a acute coronary event due to underlying ischaemic heart disease or arrhythmias.
The immediate management of this patient will include resuscitation according to BCLS protocols while maintaining the airway and breathing by leaving the patient intubated, 100% O2 and commencing CPR and defibrillation. IV adrenaline boluses 1mg of 100mcg/ml dilution and magnesium may be given. ?phenytoin.
Lipofundin as been shown to be effective in ???? it is available as given via a large bore IV line as a rapid bolus of 100ml followed by 400ml
The surgical team and family has to be informed and the patient admitted to SICU after successful resuscitatoin. ? maintainence lipofundin?Incident reporting and post event counselling.
Tuesday, June 14, 2011
Fat embolism syndrome
Clinical features:
1) hemodynamic changes: tachycardia, hypotension, desaturation
2) ECG changes: right heart strain , RV failure
3) End tidal CO2 : marked reduction due to reduced preload and cardiac output
4) Clinical: confusion, dyspnea, petechiae
Treatment:
1) initial stabilisation, 100%O2, diuretics ventilatory support and endotracheal intubation if necessary
2) CVP, aspiration of embolus ??
3) Monitoring for complications eg ARDS, DIVC
4) Arterial blood gas and 12 lead ECG
5) early fracture fixation
6) controversial: heparinisation, corticosteroids
Marks for situations where FES is likely to occur
Diagnostic criteria (combined from various sources)
Diagnostic criteria were first devised by Gurd and have been modified several times since.8,9
Major criteria
• Respiratory insufficiency
• Cerebral involvement
• Petechial rash
Minor criteria
• Tachycardia
• Pyrexia (usually >39°C)
• Confusion
• Sustained pO2 <8 kPa • Sustained respiratory rate >35/minute, in spite of sedation
• Retinal changes - cotton wool exudates and small haemorrhages, occasionally fat globules seen in retinal vessels
• Jaundice
• Renal signs
• Thrombocytopenia
• Anaemia
• High ESR
• Fat macroglobulinemia
• Diffuse alveolar infiltrates 'snow storm appearance' on chest X-ray
Causes
• Fractures - closed fractures produce more emboli than open fractures. Long bones, pelvis and ribs cause more emboli. Sternum and clavicle furnish less. Multiple fractures produce more emboli
• Orthopaedic procedures - most commonly intramedullary nailing of the long bones, hip or knee replacements4
• Massive soft tissue injury
• Severe burns
• Bone marrow biopsy
• Nontraumatic settings occasionally lead to fat embolism. These include conditions associated with:
o Liposuction5
o Fatty liver
o Prolonged corticosteroid therapy
o Acute pancreatitis
o Osteomyelitis
o Conditions causing bone infarcts, especially sickle cell disease
Presentation
There is usually a latent period of 24 to 72 hours between injury and onset. The onset is then sudden, with:
• Breathlessness ± vague pains in the chest. Depending on severity this can progress to respiratory failure with tachypnoea, increasing breathlessness and hypoxia.
• Fever - often in excess of 38.3°C with a disproportionately high pulse rate.
• Petechial rash -commonly over the upper anterior part of the trunk, arm and neck, buccal mucosa and conjunctivae. The rash may be transient, disappearing after 24 hours.
• Central nervous system symptoms, varying from a mild headache to significant cerebral dysfunction (restlessness, disorientation, confusion, seizures, stupor or coma).
• Renal - oliguria, haematuria, anuria.
• Drowsiness with oliguria is almost pathognomonic.
Predictors of fat embolism
- long bone fractures (excluding NOF)
- multiple fractures
anaesthesia for laryngectomy
Monday, June 13, 2011
opioids and opioid dependence
1). history
- baseline usage of opioids , dose and route (PO or IV)
- last intake of opioids
-nature of the pain- consistent with surgical site? Nociceptive pain?
2)clinical notes: amount of analgesia given and response to analgesia , any missed doses
3) thorough physical and psychological assessment: vital signs, symptoms of withdrawal
b. Issues of acute pain and chronic dependence, which may also be related to opioid tolerance. Larger doses than expected may be required to treat acute nociceptive pain
Multimodal analgesia involving a multidisciplinary team
long acting opioids should be given to maintain baseline requirements and avoid opioid withdrawal.
alternatives to opioids would be non opioid analgesics such as paracetamol and NSAIDS, which should be given strictly round the clock
give fast acting, long acting opioids eg oxynorm for breakthrough pain
opioid sparing techniques include splinting, ankle blocks etc.
I would avoid giving IM pethidine or other short acting opioids
refer to psychiatry for counselling
regular monitoring
establishing boundaries
commonest drugs of abuse?
laser
Laser defined as: Light Amplification by Stimulated Emission of Radiation
Hazards of use are mainly related to airway fire due to ignition by heat generated from the laser beam.
It can be minimized by surgical preparation and anaesthesia factors
Surgical preparation: use laser in short bursts
Sterile water for irrigation should always be available.
OT preparation
In the event of an airway fire, irrigation with saline or sterile water
Anaesthesia factors: use as low an FiO2 as possible (as low an oxygen concentration to maintain adequate oxygenation)
Vigilance
Use of ETT with ? wire/armoured tube
Laser may cause airway papillomas?
LASER officers, fire drill
types of laser: CO2, Yag, ?
recurrent laryngeal nerve function
RLN function can be assessed via invasive and non-invasive means
invasive test: nasoendoscopy to see weakness of unilateral glottis- inability to abduct? (remains adducted)
EMG?
non invasive: -clinical tests: presence of a leak if the patient is intubated and if the cuff is allowed to deflate, presence of stridor
RLN function can be monitored intra-op : conventional: needle electrode into cricoarytenoid. New: endoscopic visualisation (eg LMA)
The RLN (branch of the Vagus) is a mixed motor, sensory and autonomous nerve thatinnervates all intrinsic muscles of the larynx with the exceptionof the cricothyroid muscle, which is innervated by the superiorlaryngeal nerve.
ops at risk: thyroidectomy (<5%)/ACDF, carotid endarterectomy
http://www.omjournal.org/images/59_M_Deatials_Pdf_.pdf retrospective review
good review article
Sunday, June 12, 2011
LMA in dental surgery
Anaesthetic indications:
Use of a LMA in this case is less invasive than endotracheal intubation. As this surgery is most likely in the setting of ambulatory surgery, this reduces the need of muscle relaxation, reduces morbidity from sorethroat, especially if the patient is obese and is potentially difficult to intubate. The option of a flexible LMA also allows the tube to be manipulated away from the side of surgery.
Provided that the adequacy of spontaneous ventilation can be achieved to maintain adequate depth of anaesthesia.
The surgeon also has to be agreeable to the use of a supragottic device and is vigilant about suctioning of wash and secretions.
supraglottic devices, if used with adequate depth of anaesthesia, causes a lower risk of laryngospasm.
increased turnover time
easier to insert,
contraindications to LMA: patient with reflux.
disadvantages: less secure airway-may dislodge or kink, shared airway and limited access, secretions, leak with higher airway pressures (esp if obese)
intralipid/ lipid rescue
functions as a 'lipid sink' for lipophilic agents
resus according to BCLS protocols-lipid rescue-post op icu monitoring
Contents:
Purified soybean oil 200 g
Purified egg phospholipids 12 g
Glycerol anhydrous 22 g
Water for injection q.s. ad 1000 mL
pH is adjusted with sodium hydroxide to approximately pH 8.
Energy content/L: 8.4 MJ (2 000 kcal).
Osmolality (approx.): 350 mOsm/kg water. 500ml bottle: first 100ml over 15 min then 400ml over
protocol:.5ml/kg as initial bolus, then 0.25ml/kg/min for 30-60 mins
In actual resuscitation for a 70kg person: 100ml as bolus then 400ml over the next 15mins
http://www.lipidrescue.org/
TOW the blocks
peripheral
truncal: paravertebral
superficial and deep cervical plexus
brachial plexus
upper limb nerves
wrist block
lumbar plexus
femoral nerve
sciatic nerve-popliteal
ankle block
Wednesday, June 8, 2011
Australian resus council
myasthenia gravis
- Ensure that the patient is reminded prior to induction of the possibility of a prolonged intubation*
Extubation: performed on awake patients and hopefully close to his/her baseline status. Reinstitute anticholinesterase medication, either by IV infusion or by reimplementation of the patient's oral regimen.
Leventhal criteria: Predictive scoring system for the need for postoperative ventilation
1) duration of disease for 6 years or longer
2) chronic comorbid pulmonary disease
3) pyridostigmine dose >750 mg/d
4) VC <2.9L
5) Other indicators include preoperative use of steroids, and previous episode of respiratory failure.
These predictors have not been widely validated. (1)
Drugs to avoid: Calcium Channel blockers, Magnesium, Aminoglycoside antibiotics as all of these may contribute to muscle weakness
Post-Op Bed: Patients should be monitored in either a ICU or step-down unit but NOT to a conventional surgical ward.
3) MG vs eaton lambert,
tensilon to differentiate
4) baby not breathing , mother not stable
priority is to stabilise mother
baby: SpO2 88% Hr 50, chin lift and BVM (? pressure gauge), towel under shoulders. intubate , start CPR
CVS collapse most likely due to hypoxia
call code blue, adrenaline 10mcg/kg
stop CPR when HR >60
ETT adrenaline 100mcg/kg (other routes IM, umbilical)
resus guidelines :ARC
anzca anaes viva
Tuesday, June 7, 2011
TOW spine
for HCC and spine mets with cauda equina syndrome- relatively urgent op, 69 year old
Induction as per normal
log roll to special ot table , foam pillow for face. Eyes padded to delineate boundaries of orbit. Visible through mirror facing the face
IA line coz history of AF .
Hb maintained >10
atracurium infusion via tracium pump 10mg/hr, desflurane
Monday, June 6, 2011
TOW Apfel score for PONV
Thursday, June 2, 2011
TIVA for spine op
85kg young man
supine, arms tucked in, long extensions, warmer, BIS
induction as per normal ( armoured tube minus stylet, rocuronium and fentanyl)
armoured tube: NG for op, bite block, IDC. op about 3-4 hours
TIVA propofol bristol model 10-8-6 maintained at about 5-6mg/kg/hr (about 510mg/hr!!)
BIS 40-55
morphine 6mg at the end
*no nitrous or benzos but used remifentanyl 0.1mcg/kg/min
post op cervical collar
ps. usually no MEP/SSEP monitoring
Wednesday, June 1, 2011
AIMS anaesthesia analysis
THE BASIC ALGORITHM
commit to memory
C Circulation Capnograph Colour (Saturation)
O Oxygen Supply Oxygen Analyser
V Ventilation (Ventilated Pts) Vaporisers
E Endotracheal Tube Eliminate Machine
R Review Monitors Review Equipment
A Airway (if Face mask or LMA)B BreathingC Circulation (in more detail)D Drugs
A Awareness Air embolism Air in pleura Anaphylaxis
SWIFT CHECK of Patient, Surgeon and Surrounds
Change order for spontaneous breathing to:AB COVER CD A SWIFT_CHECK