L.A #7 By Bra2a Al-5a6eeb

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L.A #7 By Bra2a Al-5a6eeb

Post by Haneen Thnebat on 8/11/2011, 5:52 am


بسم الله الرحمن الرحيم

Local Anesthesia


Lec # 7


This lec is about local anesthesia contraindication and complication

No drug is without unwanted effect and most of therapeutics agent can’t be used with complete safety in all individuals coz there is a variations in the metabolism between individuals

So what are the contraindication for local anesthesia:-

1- Patient not cooperative

The basic in the local anesthesia is that the patient is cooperative ,if the patient is not cooperative we can’t go for local anesthesia.

What are the different types of patients management (we take them later on but usually we start with local anesthesia)

If local anesthesia was not successful we go for additional sedation.

Sedation : is a technique for controlling patient if L.A is not successful

If sedation is not successful we go for general anesthesia (we must know what are the indication and contraindication for general anesthesia)

- In last of this semester we will take 2 lect about sedation & general anesthesia but Usually we start our procedure with L.A

To enable treatment to be completed under L.A , collaboration is required but when the patient is not cooperative :-

a) Patient with mental or physical impairment

These patients can’t be treatment under L.A

Eg: patient with cerebrovascular accident .

These patients mange under general anesthesia after we sure that their status are suitable for general anesthesia then we go for proper management.

b) Very young children

-coz they can’t differ between painful and non painful condition

-uncooperative child cant mange him \her under L.A so go for general anesthesia

c) unreasonable patient

- this is in a few people

L.A واحد بحكيلك مستحيل أقدر انك تشتغلي تحت

If L.A impossible ->you can go for general anesthesia bus this mean we need more medication also hospital admitted & it’s more expensive

Q: when the sedition is not effective ?

Answer :if the patient is still not cooptation with sedation and Sometime the operation itself need general anesthesia not sedation so in such situations sedation is not effective

Sedation is used for minor procedure pluses / minuses

We use medazolam in the sedation which causes calm to the patient ,but If the patient has any respiratory problem ,sedation is contraindication

So sedation is contraindication when :-

1- The patient is still not cooperative

2- The operation itself need general anesthesia

3- The patient has respiratory problem

2) treatment factors

a) time consideration

Some time we have prolonged therapeutic sections , so we should go for general anesthesia not for local

b) Access problem

For example ,when we make a surgery for post. part of tongue or in the soft palate ,in these sites we can’t achieve well L.A so we go for general anesthesia.

c) Acute infection

- it reduced efficacy of L.A

-if u have a patient with acute infection and extended to the facial spaces specially if the patient has medical problem such as diabetic patient , L.A for this patient is danger on his/her life so u have to warn ur patient

sad story : one of dentists has prescribed antibiotics for diabetic patient and this mistake caused facial infection to the patient then she suffered from sepsis then shock ,stroke and finally the patient was died

- Patients with acute infection L.A not effective for them ,these patients need to be admitted to the hospital and treated under general anesthesia to make incision and drainage (we have to drainage the abscess)

Q: how the patient be not cooperative under sedation ??

Answer :v. possible that the patient is not cooperative under sedation coz sedation is like valum pill the patient is fully conscious under it

sedation just makes the patient calm and this calming depends on the patients pain threshold

d) Allergy

-not common

-some patients have allergy from L.A , for these patients L.A is absolutely contraindication u must go for general anesthesia

We have amide and ester type of L.A ,some patients have allergy from amide type others have allergy from ester type so we can’t go for that type of L.A which the patient has allergy from it

e) Medical condition

-L.A for patients that have medical problems is relatively contraindication

f) Poor bld supply

If ur patients have poor bld supply in any area ,u can’t go for L.A u have to go for general anesthesia

-the use of L.A containing vasoconstrictor should be avoided in the area where bld supply has been compromised

if u use L.A for these patients, u will not use a high concentration of vasoconstrictor (adrenalin) coz it will worsen the situation

For example , after radiotherapy in the treatment of malignancy , u should not use or reduce the L.A coz L.A cause ostionecrosis ( which is type of ostomilitis) and that cause sequestering in the jaw

g) Contraindication to specific technique

Some techniques of L.A have special contraindications:

Ø Bld diathesis

-Patients who has bleeding problem or bld problem such as patients with hemophilia , L.A for these patients is contraindication specially block anesthesia coz it cause bleeding

and it is contraindication to give these patients injection anesthesia in the floor of the mouth coz it easy to cause hematoma formation and it may expand to the air way space and compression it

**so patients with bleeding problem

1)Id block is contraindication

2)Infiltration in the floor of the mouth is contraindication

What the solution for these patients ??

Either give them infiltration injection (but not in the floor of the mouth) OR interligemantal injection(which part of supplemental injection techniques )

Ø Susceptibility to endocarditis

Patients with susceptibility to endocarditis we not give them interligemantal injection coz in the interligemantal injection we use force during giving solution and this force the pathogen and microbes to go to the bld stream then to the heart

Ø In complete root formation

Interligamental injection could be given to pediatric patients but the problem in the children is that they have incomplete root formation and we said before that interligamental injection is given under force so the tooth may go out from the socket which called tooth avulsion (this is a minimal case but it happen)

Ø Trismus

Some methods of anesthesia like Akinosi cause trismus

Trismus as u knew :is a limiting mouth opening

Ø Epilepsy / cardiac pacemaker

Patients with epilepsy or cardiac pacemaker or cerebrovascular diseases ,electronic anesthesia* for these patients should be avoided coz these patients have abnormality in the conduction and when we use electronic devise ,it will interfere with this electrical conduction

Electronic dental anesthesia*: is advanced technique which we use a special electrode that help u to achieve anesthesia ( we don’t have it in our university hospital coz it v.expensive (don’t worry about it coz usually we use conventional type of anesthesia )

H) in pregnancy

L.A in pregnancy is contraindication in the first trimester specially in the 2-8wks of pregnancy

Any dental work is contraindication in the first trimester ,so any dental work should be in the middle or 2nd trimester

Lidocaine is the safest L.A to be used

prilocaine the most diffusion

bupivacaine the least diffusion

Lignocaine?? & mepivacaine are intermediate

The best choice of local anesthesia in pregnancy is lidocaine .

Local complications

1- Local discomfort

Which is acceptable caz this is nature

U are increase the pressure of the fluid in the small area

2- interepithelial injection

it cause pain and may cause epithelium ballooning & to overcome this u should insertion the needle to submucosa

3- Sub –periosteal injection

such as palatal injection is painful coz u inject in non compliant tissue

4- Too rapid injection

u must give slow injection not rapid ideally the injection takes 30 sec in order to less the discomfort to the patient

5- Direct content with the nerve trunk

This happen with experience dentist

The patient feel electrical shock

6- Factor related to the solution

Temp and pH

pH of the local anesthesia is low and this may cause burning sensation to the patient specially if the L.A contain adrenaline

post injection pain

some patients are highly sensitive to injection specially palatal injection (which cause sloughing to the epithelium) and forceful injection .they cause desquamation and ulcer formation but this is variable between individuals

1- Sub-preiosteal injection

Result in disconnection of periostum from the bone and this is cause pain

2- Force of interligamental injection

This produce extrude of tooth and may cause desquamation to the epithelium and ulcer

- If failure of anesthesia happens that mean u have to do multiple insertion of needle and this cause pain in the injection area( the severity of the pain depends on how the patient receive this pain)

Neurological problems

1- Prolong altered sensation

-unfinishing sensation in the area of injection and this due to trauma to the nerve trunk via needle OR injection solution in the nerve trunk itself

2- Hemi-facial palsy

-to avoid this u must do eyes protection

-this is a temporary case (deleted when the anesthesia is washed out)

When u give Id block the anesthesia go to facial nerve then to the tail of parotid and this cause hemi-facial palsy

3- Visual disturbances

We have a reported cases

Patient has a blurred vision or diplopia or any of vision problems

-unilateral or bilateral

-temporary and could be permanent

we have 2 explanations of the permanent visual disturbances :

1)Anesthesia go to the origin of the artery then transmission to the ophthalmic artery to middle meningal artery to id bundle and this cause blurred vision

2) Anesthesia go to pterygoid plexus which is valveless then transmission by venous system

4- Aural disturbances:

Cause by interarterial injection of L.A which reach the internal auditory artery then reach to ophthalmic artery which causes temporary loss of function of optic nerve

5- Extensive paralysis

L.A reach to the external carotid artery then to the internal carotid artery and finally it reaches the brain and causes a temporary paralysis

**these complications mainly happen with Id block anesthesia

When we take the anatomy of arteries and nerves we studied them in 80% of people and this means that 15% of people different from what we were studied so u don’t guess what will happen

-to reduce these complications and go to the safe side u have to do aspiration before given anesthesia

Most complication of L.A

1) vasovagal attack :first mark of it patients color become paler

2) syncope

vascular problems

1- intravascular injection

2- hematoma formation

-it’s painful and we afraid from infection so u must give antibiotic if it happens

-it can cause by self infected trauma : when we give Id block and when u pull the needle out u inject the lips and cause trauma to them

3- trismus

4- infection : u must have a tray that ur instruments are put on it coz the surface is not clean ( may contaminated) and when u put the needle on it and then to the patient mouth for id block it causes infection to the patient

some theories say that the L.A may interfere with healing but the doctor doesn’t believe them

equipment failure

1- broken needle

if the needle break u shouldn’t play with it

2- cartridge failure

carpole itself is splatter or broken

it happen mainly with beginner and with pdl (interligamental injection) coz it is given with force and this may cause break to carpole

**so slow rate of injection is recommended

L.A systematic adverse effect


U need to know the does /weight u deal with and it different between indivisibly(adult ,child ,old)

Take in ur consideration if the patient has medically problem

Cardiovascular toxicity

1- excitation phase

start with elevation in the bld pressure and tachycardia

2- depression phase

negative ionotropic on the heart that affect cardiac output and stroke volume and this cause hypotension

3- Cardiovascular collapse

It happens to support theCardiovascular function

Treatment by: - fluid

- cpr

- o2

U have to lower the amount of anesthesia in the patient with Cardiovascular problem for example lidocaine we give 10 carpoles that contain it for adult healthy patients but for patients with cardiovascular problem maximum we give 4 carpoles to them

pediatric -> we give them 2 carpoles

Most local anesthesia they case depressant action of the heart

L.A may cause methameoglobinaemia (this is the main toxic effect of procaine which causes cyanosis)

Methameoglobinaemia is a hemoglobin which contains iron in the ferric rather than in the ferrous state let reduces the red bld cells oxygen carrying capacity

This cause : - cyanosis

- lethargy

- respiratory distress

How to deal with this condition??

By give the patient methalen blue

Methameoglobinaemia happen due to one of prilocaine metabolized….cause oxidation to ferrous ion (this is a Q in any universal exam)

May this condition happens with articaine and bupivacaine

The best treatment is prevention by :

1) aspiration before inject anesthesia

2) slow injection

3) dose limitation

CNS toxicity

Marks :

1- excitation phase

restlessness , preoral numbness if the patient feel them u should stop the procedure

2- convulsive phase


3- depression phase

with drowsiness and unconsciousness

4- respiratory depression and apnea phase

treatment by: 1- given the patient diazepam (5-10 mg) specially if the patient in the seizure state

2- u need to have o2 mask

If we have any medical problem u must start with ABCS and call to emergency

Adrenaline toxicity

1. adrenaline toxicity

it has asympathomaic effect coz it effect on different receptors α,β receptors

toxicity of adrenaline cause :

1- anxiety

2- restlessness

3- tremor

4- thropping headache

5- palpitation :

lidocaine can use in treatment of ventricular arthmia

6- sweating

7- dizziness

8- respiratory distress

if u have adrenaline overdose u must :

1- stop the treatment

2- reduce the bld pressure by setting the patient upright position

3- o2 administration

cardiovascular problems

-patients with hypertension should not give them L.A u prefer to give them plain anesthesia

- patients with unstable angina ,MI, these patients prefer to not make dental work to them but if u go to dental work use plain anesthesia

- patients with hyperthyroid u shouldn’t give them L.A with vasoconstrictor coz it cause crysis and malignant hypertension crebrovascular accident

** u must ask ur patient about all of these points to safe life

Systematic effects

-when adrenaline is contraindication in the L.A u can use felypressin instead of adrenaline but it not highly safety

-felypressin at high concentration it cause coronary constriction so u need to limit the amount of felypressin containing solution to lower than 3 carpoles

Adverse effects of other constituent of L.A :

-pay attention of allergic rxn that result from presvative specially methild parapell ?

** some L.A contain sulfide but now the new types don’t have it

The problem in sulfide that it is allergen specially in asthmatic patients it causes asthmatic attack so u must take a good medical history of ur patients

Best Wishes

Done By:
Bara’ah Al-khateeb
Haneen Thnebat

عدد المساهمات : 152
النشاط : 6
تاريخ التسجيل : 2009-09-09

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