NEET MDS Synopsis
Emergency Drugs
Anaesthesia
Emergency Drugs for Sedated Patients (AAPD Guidelines)
In the context of pediatric dentistry and sedation, it is crucial to be prepared
for potential emergencies that may arise during or after sedation. The following
is a list of emergency drugs that may be needed to rescue a sedated patient,
along with their indications and uses.
Emergency Drugs
Albuterol for Inhalation
Indication: Bronchospasm or asthma exacerbation.
Use: Administered via nebulizer or metered-dose inhaler to
relieve bronchospasm.
Ammonia Spirits
Indication: Syncope or fainting.
Use: Inhaled to stimulate respiration and increase alertness.
Atropine
Indication: Bradycardia or asystole.
Use: Increases heart rate by blocking vagal effects on the
heart.
Diazepam
Indication: Seizures or severe anxiety.
Use: Administered intravenously or intramuscularly for rapid
sedation or seizure control.
Diphenhydramine
Indication: Allergic reactions or anaphylaxis.
Use: Antihistamine for allergic symptoms; may also be used for
sedation.
Epinephrine (1:1,000 and 1:10,000)
Indication: Anaphylaxis or severe asthma attack.
Use: 1:1,000 for intramuscular injection; 1:10,000 for
intravenous administration in cardiac arrest.
Flumazenil
Indication: Benzodiazepine overdose.
Use: Reversal agent for sedation caused by benzodiazepines.
Fosphenytoin
Indication: Status epilepticus.
Use: Anticonvulsant for seizure control, administered
intravenously.
Glucose (25% or 50%)
Indication: Hypoglycemia.
Use: Administered intravenously to rapidly increase blood
glucose levels.
Lidocaine
Indication: Cardiac arrhythmias or local anesthesia.
Use: Antiarrhythmic agent for ventricular arrhythmias; also
used for local anesthesia.
Lorazepam
Indication: Anxiety or seizures.
Use: Sedative and anticonvulsant, administered intravenously or
intramuscularly.
Methylprednisolone
Indication: Severe allergic reactions or inflammation.
Use: Corticosteroid for reducing inflammation and managing
allergic reactions.
Naloxone
Indication: Opioid overdose.
Use: Opioid antagonist to reverse respiratory depression and
sedation caused by opioids.
Oxygen
Indication: Hypoxia or respiratory distress.
Use: Administered to improve oxygen saturation and support
respiratory function.
Racemic Epinephrine
Indication: Croup or severe bronchospasm.
Use: Administered via nebulization to reduce airway swelling
and improve breathing.
Rocuronium
Indication: Neuromuscular blockade for intubation.
Use: Non-depolarizing neuromuscular blocker for facilitating
intubation.
Sodium Bicarbonate
Indication: Metabolic acidosis or hyperkalemia.
Use: Administered intravenously to correct acidosis and manage
elevated potassium levels.
Succinylcholine
Indication: Rapid sequence intubation.
Use: Depolarizing neuromuscular blocker for quick intubation.
Surface Tension
PhysiologySurface Tension
1. Maintains stability of alveolus, preventing collapse
2. Surfactant (Type II pneumocytes) = dipalmityl lecithin
3. Type II pneumocyte appears at 24 weeks of gestation;
1. Surfactant production, 28-32 weeks;
2. Surfactant in amniotic fluid, 35 weeks.
3. Laplace equation for thin walled spheres P = 2T
a. P = alveolar internal pressure r
b. T = tension in the walls r = radius of alveolus
4. During normal tidal respiration
1. Some alveoli do collapse (Tidal pressure can't open)
2. Higher than normal pressure needed (Coughing)
3. Deep breaths & sighs promote re-expansion
4. After surgery/Other conditions, Coughing, deep breathing, sustained maximal respiration
Coronoid Fracture
Oral and Maxillofacial SurgeryCoronoid Fracture
A coronoid fracture is a relatively rare type of fracture
that involves the coronoid process of the mandible, which is the bony projection
on the upper part of the ramus of the mandible where the temporalis muscle
attaches. This fracture is often associated with specific mechanisms of injury
and can have implications for jaw function and treatment.
Mechanism of Injury
Reflex Muscular Contraction: The primary mechanism
behind coronoid fractures is thought to be the result of reflex
muscular contraction of the strong temporalis muscle. This can
occur during traumatic events, such as:
Direct Trauma: A blow to the jaw or face.
Indirect Trauma: Situations where the jaw is
forcibly closed, such as during a seizure or a strong reflex action
(e.g., clenching the jaw during impact).
Displacement: When the temporalis muscle contracts
forcefully, it can displace the fractured fragment of the coronoid process
upwards towards the infratemporal fossa. This displacement
can complicate the clinical picture and may affect the treatment approach.
Clinical Presentation
Pain and Swelling: Patients with a coronoid fracture
typically present with localized pain and swelling in the region of the
mandible.
Limited Jaw Movement: There may be restricted range of
motion in the jaw, particularly in opening the mouth (trismus) due to pain
and muscle spasm.
Palpable Defect: In some cases, a palpable defect may
be felt in the area of the coronoid process.
Diagnosis
Clinical Examination: A thorough clinical examination
is essential to assess the extent of the injury and any associated
fractures.
Imaging Studies:
Panoramic Radiography: A panoramic X-ray can help
visualize the mandible and identify fractures.
CT Scan: A computed tomography (CT) scan is often
the preferred imaging modality for a more detailed assessment of the
fracture, especially to evaluate displacement and any associated
injuries to surrounding structures.
Treatment
Conservative Management: In cases where the fracture is
non-displaced or minimally displaced, conservative management may be
sufficient. This can include:
Pain Management: Use of analgesics to control pain.
Soft Diet: Advising a soft diet to minimize jaw
movement and stress on the fracture site.
Physical Therapy: Gradual jaw exercises may be
recommended to restore function.
Surgical Intervention: If the fracture is significantly
displaced or if there are functional impairments, surgical intervention may
be necessary. This can involve:
Open Reduction and Internal Fixation (ORIF):
Surgical realignment of the fractured fragment and stabilization using
plates and screws.
Bone Grafting: In cases of significant bone loss or
non-union, bone grafting may be considered.
Methods of general anesthesia
Pharmacology
Methods of general anesthesia
CIRCLE SYSTEM
*HIGH-FLOW
FRESH GAS FLOW > 3 l/min.
*LOW-FLOW
FGF ok. 1l/min.
*MINIMAL-FLOW
FGF ok. 0,5 l/min.
Treatment modifications to consider if there are concerns regarding vasoconstrictors
Pharmacology
Treatment modifications to consider if there are concerns regarding vasoconstrictors
- Monitor blood pressure and heart rate preoperatively
- Minimize administration of epinephrine or levonordefrin
- Monitor blood pressure and heart rate 5 min after injection
- May re-administer epinephrine or levonordefrin if blood pressure and heart rate are stable
- Continue to monitor as required
- Consider limiting epinephrine to 0.04 mg, levonordefrin to 0.2 mg
- Avoid epinephrine 1:50,000
- Never use epinephrine-impregnated retraction cord
Hereditary spherocytosis
General Pathology
Hereditary spherocytosis.
Functionally normal cells which are destroyed .in spleen because of the structural abnormality. It is transmitted as an autosomal dominant trait
Congenital hemolytic anemia due to genetically determined abnormal spectrin and ankyrin molecules, leading to defects in red blood cell membrane, causing spherical shape and lack of plasticity
Red blood cells become trapped within spleen and have less than usual 120 day lifespan
Splenic function is normal
Osmotic fragility: increased; basis for diagnostic testing
Description
Firm, deep red tissue, thin capsule, no grossly identifiable malpighian follicles, 100-1000g
Peripheral blood images
Marked congestion in cords
Sinuses appear empty but actually contain ghost red blood cells
May have prominent endothelial lined sinuses, hemosiderin deposition, erythrophagocytosis
Berkson's Bias
Public Health DentistryBerkson's Bias is a type of selection bias that occurs in
case-control studies, particularly when the cases and controls are selected from
a hospital or clinical setting. It arises when the selection of cases
(individuals with the disease) and controls (individuals without the disease) is
influenced by the presence of other conditions or factors, leading to a
distortion in the association between exposure and outcome.
Key Features of Berkson's Bias
Hospital-Based Selection: Berkson's Bias typically
occurs in studies where both cases and controls are drawn from the same
hospital or clinical setting. This can lead to a situation where the
controls are not representative of the general population.
Association with Other Conditions: Individuals who are
hospitalized may have multiple health issues or risk factors that are not
present in the general population. This can create a misleading association
between the exposure being studied and the disease outcome.
Underestimation or Overestimation of Risk: Because the
controls may have different health profiles compared to the general
population, the odds ratio calculated in the study may be biased. This can
lead to either an overestimation or underestimation of the true association
between the exposure and the disease.
Example of Berkson's Bias
Consider a study investigating the relationship between smoking and lung
cancer, where both cases (lung cancer patients) and controls (patients without
lung cancer) are selected from a hospital. If the controls are patients with
other diseases that are also related to smoking (e.g., chronic obstructive
pulmonary disease), this could lead to Berkson's Bias. The controls may have a
higher prevalence of smoking than the general population, which could distort
the perceived association between smoking and lung cancer.
Implications of Berkson's Bias
Misleading Conclusions: Berkson's Bias can lead
researchers to draw incorrect conclusions about the relationship between
exposures and outcomes, which can affect public health recommendations and
clinical practices.
Generalizability Issues: Findings from studies affected
by Berkson's Bias may not be generalizable to the broader population,
limiting the applicability of the results.
Mitigating Berkson's Bias
To reduce the risk of Berkson's Bias in research, researchers can:
Select Controls from the General Population: Instead of
selecting controls from a hospital, researchers can use population-based
controls to ensure a more representative sample.
Use Multiple Control Groups: Employing different control
groups can help identify and account for potential biases.
Stratify Analyses: Stratifying analyses based on
relevant characteristics (e.g., age, sex, comorbidities) can help to control
for confounding factors.
Conduct Sensitivity Analyses: Performing sensitivity
analyses can help assess how robust the findings are to different
assumptions about the data.
The hepatic portal system
PhysiologyThe hepatic portal system
The capillary beds of most tissues drain into veins that lead directly back to the heart. But blood draining the intestines is an exception. The veins draining the intestine lead to a second set of capillary beds in the liver. Here the liver removes many of the materials that were absorbed by the intestine:
Glucose is removed and converted into glycogen.
Other monosaccharides are removed and converted into glucose.
Excess amino acids are removed and deaminated.
The amino group is converted into urea.
The residue can then enter the pathways of cellular respiration and be oxidized for energy.
Many nonnutritive molecules, such as ingested drugs, are removed by the liver and, often, detoxified.
The liver serves as a gatekeeper between the intestines and the general circulation. It screens blood reaching it in the hepatic portal system so that its composition when it leaves will be close to normal for the body.
Furthermore, this homeostatic mechanism works both ways. When, for example, the concentration of glucose in the blood drops between meals, the liver releases more to the blood by
converting its glycogen stores to glucose (glycogenolysis)
converting certain amino acids into glucose (gluconeogenesis).