Head and Neck, ENT, Dental Surgery and ECT Flashcards
NP The use of intraoperative dexamethasone for tonsillectomy:
a) Increased oedema
b) Increased post tonsillectomy bleed
c) Increased Analgesic requirement
d) Reduced time to resumption of oral intake
REPEAT
d) Reduced time to resumption of oral intake
The effect of preoperative dexamethasone on early oral intake, vomiting and pain after tonsillectomy
https://pubmed.ncbi.nlm.nih.gov/15979735/
Conclusion: Preoperative dexamethasone use significantly reduces early posttonsillectomy pain, improves oral intake and facilitates meeting the discharge criteria while using standard anesthesia technique and sharp dissection tonsillectomy without any significant side effects.
The sensor on a NIM (Nerve Integrity Monitor) endotracheal tube used for thyroid surgery directly records
a. Electromyography of internal laryngeal muscles
b. Recurrent laryngeal nerve action potential
c. Movement of the vocal cords on the endotracheal tube
d. Pressure of the vocal cords on the endotracheal tube
e. Recurrent laryngeal nerve action potential
AT - REPEAT
a. Electromyography of internal laryngeal muscles
True - the NIM-EMG tube tests RLN function via EMG of the muscles
wiki:
Notably, the only muscle capable of separating the vocal cords for normal breathing is the posterior cricoarytenoid. If this muscle is incapacitated on both sides, the inability to pull the vocal folds apart (abduct) will cause difficulty breathing. Bilateral injury to the recurrent laryngeal nerve would cause this condition. It is also worth noting that all muscles are innervated by the recurrent laryngeal branch of the vagus except the cricothyroid muscle, which is innervated by the external laryngeal branch of the superior laryngeal nerve (a branch of the vagus).
Anaesthesia: Nerve Integrity Monitor tubes for thyroid surgery (2014)
Recurrent laryngeal nerve function should be monitored during thyroid surgery [1], either by direct observation of vocal cord function during surgery [2], which can be difficult, or by electromyography (EMG), during which electrodes are placed adjacent to the vocal cords to detect motion when the laryngeal nerves are stimulated. Electrodes can be secured to the outside of a tracheal tube so that they come into contact with the vocal cords during intubation [3]. Indeed, electrodes have been embedded into the material of the tracheal tube (Medtronic Nerve Integrity Monitor (NIM) Standard Reinforced EMG Endotracheal Tube, Medtronic Xomed Inc., Jacksonville, FL, USA), albeit leading to an increase in bulk and external diameter in comparison with equivalent internal diameter tubes (Fig. 2). The size and rigidity of the NIM tubes mandate oral tracheal intubation rather than nasal intubation, which itself is further inhibited by the positioning of cable attachments for the electrodes along the tube’s length.
http://smpp.northwestern.edu/bmec66/weightlifting/emgback.html
An electromyography (EMG) is a measurement of the electrical activity in muscles as a by product of contraction. An EMG is the summation of action potentials from the muscle fibers under the electrodes placed on the skin. The more muscles that fire, the greater the amount of action potentials recorded and the greater the EMG reading.
http://www.shanahq.com/main/content/reliable-technique-make-nim-tube-work-preview
The specialized endotracheal tubes (ETT), such as Xomed and TriVantage Nerve Integrity Monitoring (NIM) ETTs (Medtronic Xomed Inc., Jacksonville, FL USA) allow for RLN identification through continuous intraoperative EMG monitoring of the laryngeal muscles.
https://www.aana.com/newsandjournal/Documents/jcourse1_0410_p151-160_rev2.pdf
The Medtronic NIM electromyographic (EMG) endotracheal tube (Medtronic Xomed) is constructed of a flexible silicone elastomer and has a distal inflatable cuff.
The tube is fitted with 4 stainless steel wire electrodes (2 pairs) that are embedded in the silicone of the main shaft distance, slightly superior to the cuff. The electrodes are designed to make contact with the patient’s vocal cords to facilitate EMG monitoring of the RLN when connected to a multichannel EMG monitoring device. If monitoring correctly, the EMG monitor should show a consistent sound signal and an action potential tracing.
J Anaesthesiol Clin Pharmacol: The neural integrity monitor electromyogram tracheal tube: Anesthetic considerations (2013)
When attempting to identify LNs, a stimulating electrical current of 0.5-2.0 mA is used by the surgeon. This current is administered via a sterile probe, which is placed directly on the anatomical site in question. Additionally, return electrodes are positioned in the skin above the sternum.
When a LN is located, an electrical signal is subsequently generated by the motion of the vocal cords. An audibly recognizable “machine gun click” is then produced from the device’s associated monitor. This sound has a set frequency of 4 times/s (4 Hz). Simultaneously, an oscilloscope-like screen displays an identifiable sinusoidal response.
22.2 The sensor on a NIM (Nerve Integrity Monitor) endotracheal tube used for thyroid surgery directly records
a. Electromyography of internal laryngeal muscles
b. Recurrent laryngeal nerve action potential
c. Movement of the vocal cords on the endotracheal tube
d. Pressure of the vocal cords on the endotracheal tube
e. Recurrent laryngeal nerve action potential
a. Electromyography of internal laryngeal muscles
20.2 Cardiovascular effects of hyperthyroidism include
a) Decreased CO
b) Increased PVR
c) Increased DBP
d) Decreased SVR
Decreased SVR
Hyperthyroidism:
increases HR
increases cardiac contractility.
increases LVEF
increases diastolic relaxation
increases CO
SVR decreases
>T3 induces systemic vasodilation.
20.1 Cardiovascular effects of hyperthyroidism include
a) decreased diastolic relaxation
b) decreased SVR
c) decreased PVR
d) increased diastolic BP
Decreased SVR
- increased CO, increased SBP and decreased DBP with widened PP
Up to Date
Cardiovascular - Patients with hyperthyroidism have an increase in cardiac output, due both to increased peripheral oxygen needs and increased cardiac contractility. Heart rate is increased, pulse pressure is widened, and peripheral vascular resistance is decreased
20.1 Interventions that reduce the risk of agitation following electroconvulsive therapy include all of the following EXCEPT
a Low dose of propofol following the seizure
b Low dose of midazolam following the seizure
c Premedication with olanzapine
d Premedication with dexmedetomidine
e Induction with remifentanil
e) Remifentanil bolus
Induction agents:
Propofol:
-0.75-2.5mg/kg
- shortest seizure duration
- improved CVS stability, less PONV, quicker emergence
- pain on injection
Etomidate
- 0.15-0.3mg/kg
- Prolonged seizure activity, may reduce seizure threshold
- Useful in resistant seizures
- Hyperdynamic response more pronounced compared with propofol, increased PONV, longer emergence time
Methohexital
- 0.5-1.5 mg/kg
- “gold standard” for ECT seizure quality
- long history of use
- reduced availability; lack of familiarity with sue
Thiopental
- 2-5mg/kg
- Seizure duration reduced but better than propofol
- need to reconstitute, has increased dysrhythmias
Ketamine
- 0.7-2.8mg/kg
- unclear effect on seizures: reduced and prolongesd in different studies
- usefull in resistant seizures
- emergence phenomena, reduced CVS stability and increases ICP
Sevoflurane
-6-8% inspired concentration; MAC1-2
- reduced seizure duration compared to methohexital
- useful if difficult IV access, reduces uterine contractions in pregnancy
- extra equipment needed; more time consuming
Induction agents in the descending order of CMRO2 reducing ability:
Propofol > sevoflurane > thiopental and methohexital > etomidate > ketamine.
Induction agents in the descending order of CBF and ICP reducing ability:
Propofol > thiopental and methohexital > etomidate > ketamine.
Induction agents in the descending order of emergence time:
Ketamine > etomidate > barbiturates > propofol > sevoflurane.
Emergence time is the time from drug administration for general anaesthesia till eye opening or following commands. The differences in emergence time among induction agents suitable for ECT are small, and these small variations in emergence should not govern drug choice.
Induction agents in descending order of seizure threshold reducing property are:
Etomidate > ketamine > methohexital > thiopental > propofol.
Opioid:
- Alfentanil (10-20mcg/kg) or remifentanil (1mcg/kg) can be used along with the induction agent to increase the seizure duration and reduce haemodynamic response.
- It is unclear if the effect on seizure duration is an inherent effect of the opioid or as a result of its dose sparing effect.
NMB:
-Neuromuscular blocking agents reduce muscular convulsions and decrease the risk of serious injury.
- Sux at 0.5mg/kg most commonly used, larger doses upto 1.5mg/kg nay be required
Adjuncts:
- used to reduce dose of induction agent, or mitigate cardiovascular response to ECT in high risk patients
- To treat adverse PNS effects
Glycopyrolate: - superior anti-sialogogue effect
- no adverse CNS effects
- less post ECT tachycardia
Atropine - routine atropine pre-medicattion is not recommended due to adverse effects of increased myocardial work and O2 demand
To treat Adverse SNS effects:
- B-blockers: atenolol (pre-ECT) or labetalol and esmolol (intra-ECT), this may reduce seizure duration
-CCB: sublingual nifedapine and IV nicardipine for Htn but may reduce seizure duration
- a-2 agonists: Dexmedetomidine blunts the hyperdynamic rsponse as does GTN and should be considered in patients at high risk of ischaemia
- Dexmedetomidine reduces the incidence of post-ECT adverse effects such as headache, agitation, postictal delirium, or pain associated with propofol injection
-IV lignocaine is not effective
Emergence agitation:
- Small doses of midazolam may be useful if simple measures such as a secluded, calm recovery environment do not help
-However, we avoid administration of any benzodiazepine such as midazolam before performing an ECT procedure, due to known anticonvulsant properties that would make seizure induction more difficult
- In patients with a history of severe postictal agitation, intravenous (IV) benzodiazepines or propofol may be administered at the end of the seizure Dexmedetomidine may be useful in the treatment of refractory cases
21.2 A 25-year-old male has continued post operative bleeding after an extraction of an impacted third molar tooth under a general anaesthetic. The patient mentions that his father bruises quite easily. His coagulation screen reveals: (Coagulation tests provided). The most likely diagnosis is
His coagulation screen reveals: Prolonged APTT, Normal PT.
a) Factor V Leiden
b) Haemophilia A
c) Haemophilia B
d) Von willebrand disease
d) Von willebrand disease
- autosomal dominant inheritance
- may have normal or prolonged APTT, PT is normal
*Haem A: X-linked recessive disorder; would expect prolonged aPTT, and normal PT
*Haem B: X-linked recessive disorder; would expect normal aPTT and normal PT
Up to date:
Inheritance patterns — Most cases of VWD are transmitted as an autosomal dominant trait; this includes types 1 and 2B, and most types 2A and 2M.
Baseline hemostasis assessment —
Most patients will have a complete blood count (CBC) with platelet count and coagulation studies during the initial evaluation for excessive bleeding or bruising.
●Individuals with VWD generally have a normal CBC and a normal platelet count, with the exception of those with type 2B VWD, most of whom will have mild thrombocytopenia (eg, platelet count 100,000 to 140,000/microL).
●Individuals with VWD may have a normal or prolonged activated partial thromboplastin time (aPTT), depending on the degree of reduction of the factor VIII level. The prothrombin time (PT) is normal in VWD.
Up to date:
●Hemophilia A – Inherited deficiency of factor VIII (factor 8 [F8]); an X-linked recessive disorder.
●Hemophilia B – Inherited deficiency of factor IX (factor 9 [F9]); also called Christmas disease; an X-linked recessive disorder.
Laboratory findings —
Hemophilia is characterized by a prolonged activated partial thromboplastin time (aPTT).
However, the aPTT may be normal in individuals with milder factor deficiencies (eg, factor activity level >15 percent), especially in hemophilia B (factor IX deficiency), where even individuals with moderate disease may have a normal aPTT.
In some individuals with hemophilia A, factor VIII levels may increase with stress, leading to a normalization of the aPTT or mis-categorization of factor levels and disease severity.
In patients with hemophilia, the aPTT corrects in mixing studies, unless an inhibitor is present, which only applies to individuals who have received factor infusions or who have an autoantibody such as a lupus anticoagulant or an acquired factor inhibitor.
Mixing studies that do not show correction of a prolonged aPTT suggest an alternative diagnosis such as an acquired factor inhibitor.
The platelet count and prothrombin time (PT) are normal in hemophilia.
Thrombocytopenia and/or prolonged PT suggest another diagnosis instead of (or in addition to) hemophilia.
Measurement of the factor activity level (factor VIII in hemophilia A; factor IX in hemophilia B) shows a reduced level compared with controls (generally <40 percent).
One exception is an individual with mild hemophilia A who undergoes testing when stressed or pregnant and has a falsely elevated factor level. If this is suspected, factor activity testing should be repeated under conditions of low stress.
The plasma von Willebrand factor antigen (VWF:Ag) is normal in hemophilia.
If VWF:Ag is reduced, this suggests the possibility of von Willebrand disease (VWD) rather than (or in addition to) hemophilia.
Urinalysis is not done routinely, but if performed it may sometimes (but not always) show microscopic or macroscopic hematuria.
23.1 Of the following, the drug that is LEAST likely to provide effective analgesia following paediatric tonsillectomy is
A. Inhalational anesthesia
B. Remifentanil at end of case
C. Dexamethasone
D. Intranasal ketamine
or
a. Ketamine
b. Clonidine
c. NSAIDs
d. Paracetamol
e. Dexamethasone
A. Inhalational anesthesia
or
b. Clonidine
Prospect: two studies focused on tonsillectomy, and those did not show any additional analgesic effect of clonidine when used on top of adequate baseline medication after tonsillectomy.
PROSPECT
https://associationofanaesthetists-publications.onlinelibrary.wiley.com/doi/10.1111/anae.15299#:~:text=The%20basic%20analgesic%20regimen%20should,analgesic%20and%20anti%2Demetic%20effects.
21.2 Cardiovascular effects of hyperthyroidism include
a) Increased DBP
b) Narrow pulse pressure
c) Reduced diastolic relaxation
d) Decreased CO
e) Decreased SVR
e) Decreased SVR
- increased CO, increased SBP and decreased DBP with widened PP
UP TO DATE: Cardiovascular effects of hyperthyroidism:
- Thyroid hormone has important effects on cardiac muscle, the peripheral circulation, and the sympathetic nervous system that alter cardiovascular hemodynamics in a predictable way in patients with hyperthyroidism.
- The main changes are :
●Increases in heart rate, cardiac contractility, systolic and mean pulmonary artery pressure, cardiac output, diastolic relaxation, and myocardial oxygen consumption
●Reductions in systemic vascular resistance and diastolic pressure
20.1 A 55-year-old lady scheduled for a transphenoidal hypophysectomy undergoes an oral glucose tolerance test with the following results:
GH normal <10
Time 0, BSL 5.5, GH 30, IGF-1 790 (elevated)
Time 30, BSL 7.6, GH 24
Time 60, BSL 7.2, GH 28
Time 90, BSL 6.5, GH 26
Time 120, BSL 5.8, GH 29
These results are most consistent with a diagnosis of
A. Prolactinoma
B. Acromegaly
C. Cushing’s
D. MEN 2
E. Normal
Acromegaly
IGF-2 is consistently elevated
GH should be suppressed by glucose load in healthy
pt.
The continued elevation of GH despite glucose is
suggestive of acromegaly
22.2 The use of intraoperative dexamethasone for tonsillectomy
a) Increased oedema
b) Increased post tonsillectomy bleed
c) Increased Analgesic requirement
d) Reduced time to resumption of oral intake
d) Reduced time to resumption of oral intake
The effect of preoperative dexamethasone on early oral intake, vomiting and pain after tonsillectomy
https://pubmed.ncbi.nlm.nih.gov/15979735/
Conclusion: Preoperative dexamethasone use significantly reduces early posttonsillectomy pain, improves oral intake and facilitates meeting the discharge criteria while using standard anesthesia technique and sharp dissection tonsillectomy without any significant side effects.
20.1 During a tracheostomy, what vessel is most at risk beneath tracheostomy and above sternal notch?
a) Superior thyroid artery
b) Brachicephalic Vein
c) Brachiocephalic artery
d) Inferior thyroid artery
e) Carotid artery
brachiocephalic artery
BJA: Emergency FONA in airway management
“Major vessels, most commonly the brachiocephalic artery, traverse the anterior tracheal wall in up to 53% patients at the suprasternal notch.”
20.1 A patient with von Willebrand deficiency Type 1 presents with mild but persistent epistaxis.
First-line medical therapy should include:
a) Factor VII
b) Factor VIII
c) Recombinant von Willebrand factor
d) TXA
e) FFP
d) TXA
VWD Types:
1 - quantitative - minor effect on bleeding - DDAVP useful
2 - qualitative - spectrum of effects on bleeding - (2a,2b,2m,2n) - DDAVP may be useful in consult with haem
3 - absence - major bleeding - no effect of DDAVP
factors not recommended in Type 1
TXA and DDAVP are recommended but DDAVP not in list
TXA 10mg/kg IV q8h
DDAVP 300mcg intranasal 90-120 mins preop
(DDAVP increases factor VIII levels 2-5x via release of VWF which binds VIII and prevents its clearance)
Treatment of bleeding in an individual with von Willebrand disease (VWD) depends on:
1. Severity of bleeding
2, Site of bleeding
3. the type of VWD
4. the previous responses to therapy.
The two main approaches:
1. Increasing the level of normal von Willebrand factor (VWF) activity via DDAVP
2. Replacing the defective VWF with VWF concentrates
VWF concentrates have been demonstrated to provide excellent to good hemostasis in a number of patient populations and a number of bleeding types.
DDAVP is only effective in some individuals, produces a smaller increase in VWF activity, and has a later onset and shorter duration of action.
21.2 A 30-year-old man with morbid obesity (body mass index [BMI] 55 kg/m2) presents for middle ear surgery. The most appropriate bolus dose of propofol for induction should be based on
a) IBW
b) TBW
c) ABW
d) LBW
e) PBW
d) LBW
23.1 In preschool-aged children having tonsillectomy under general anaesthesia, delirium
is more likely with the use of
a. Inhalational anesthesia
b. Remifentanil at end of case
c. Dexamethasone
d. Intranasal ketamine
a) inhalational anaesthesia
https://resources.wfsahq.org/atotw/emergence-delirium-in-pediatric-patients/
20.2 In order to provide adequate anaesthesia for operation on the earlobe, the following nerve/s need to be blocked
a) Greater auricular
b) Auriculotemporal
c) Vagal auricular branch
d) Lesser occiptal nerve
e) Zygomaticotemporal
a) Greater auricular
23.1 The sensory supply of the external nose is provided by all of the following nerves EXCEPT the
A. Lacrimal
B. Supratrochlear
C. Infratrochlear
D. Infraorbital
E. Anterior ethmoidal
Lacrimal
