Preparing the patient for surgery

This ties in with our previous lesson about the patient histories (medical, dental and social) and applies it to the surgical principles. Preparing our patients for surgery involves a careful assessment of their physical and mental health and whether they can tolerate the surgical procedure. We should anticipate and account for any issues from their history that could cause complications.

The American Society of Anaesthesiologists (ASA) Classification of physical status is a useful parameter to gage how at risk the patient is when going through a surgical procedure, and if additional environmental support is necessary.

Furthermore, patient anxiety can be measured using the Modified Dental Anxiety Score (MDAS). The MDAS score combined with the ASA classification is used to help decide, if surgery can be performed under Local anaesthetic (LA) or whether it will require more specialist treatment such as sedation or general anaesthesia (GA).

The ASA classification

ASA I: A normal healthy patient

ASA II: A patient with mild systemic disease or significant health risk factor.

ASA III: A patient with severe systemic disease that is not incapacitating (prevent from functioning in a normal way).

ASA IV: A patient with severe systemic disease that is a constant threat to life.

ASA V: A moribund patient who is not expected to survive without the operation.

ASA VI: A declared brain dead patient whose organs are being removed for donation purposes. 

Systemic health, medical emergencies - clinical relevance

Note: Medical Emergencies - below is an overview to provide an understanding of their clinical relevance; please ensure to seek current guidance where appropriate - see third party reading and references to assist further reading. Remember: always call for help.

Syncope

This is the most commonly encountered medical emergency in the dental setting (63%) [1]. Syncope is a transient loss of consciousness (TLOC). It usually has a rapid onset, short duration and a spontaneous complete recovery.

Vasovagal syncope is the most common type of syncope and when seen in the dental setting, is often caused by anxiety. This is a reflex syncope; essentially, the inhibitory reaction to anxiety over compensates, leading to cardio-inhibition (parasympathetic - vagus nerve) and vasodilation (decrease sympathetic stimulus), all all which leads to a sudden drop in blood pressure (hypotension), and consequently, a drop in posture as well i.e. faint (TLOC).

Behavioural management or sedation can be used to manage the anxious patient [2]. 

Management:

In the case of syncope the patient’s legs can be elevated and loosen tight clothing if necessary, and oxygen can be provided, but isn’t always necessary [1]. Note: if unsure of the cause, further investigations will be needed most likely a secondary care facility or GP.

Allergic reaction

Before dentistry became latex free this was the most common allergen [2]. Other materials that have shown to be allergens are nickel and methyl methacrylate. An allergic reaction can be classified into one of the 4 categories of hypersensitivity (see immunology topic area for more detail). For simplicity, we will consider the reactions as mild or severe.

Mild allergic reaction

This may result in the following symptoms:

• Itching
• Hives
• Rash 

Important: the patient’s airway will be patent and their breathing should not be affected, the patient should also be fully conscious. Remove trigger if known.

Severe allergic reaction

A severe episode of anaphylaxis (severe generalise/ systemic allergic reaction + airway compromise) can be life threatening if not attended to urgently. In an episode of a severe anaphylactic reaction, symptoms could include (in addition to the above): 

• Sudden onset
• Mucosal changes
• Flushing and/or Pale and clammy - cyanosis as things progress
• Puritus
• Erythema
• Angiodema - swelling of the airway
• Stridor (harsh vibrating noise when breathing)/Wheezing
• Confusion
• Loss of consciousness or soon to lose consciousness
• Respiratory distress (SOB) - soon to become respiratory arrest
• Hypotension
• Tachycardia (elevated heart rate)/ bradycardia (shock) and soon to become cardiac arrest.

Management:

Trigger is removed.

ABCDE algorithm. The patient’s airway is at high risk, oxygen is administered and if breathing has ceased a positive pressure bag-valve-mask device can be used alongside CPR procedures. An ambulance should be called if in the primary care setting. 

Common medications used:

• Anaphylaxis: Intramuscular adrenaline (epinephrine) can be administered - when conscious. If the patient has gone into cardiac arrest, current guidance suggests not to administer IM. This is due to the poor blood flow through the muscle, leading to inadequate distribution.
• Common Dosages: 1:1000 adrenalin
  • < 6yrs - 150 micrograms (0.15ml)
  • 6-12yrs - 300 micrograms (0.3ml)
  • >12yrs - 500 micrograms (0.5ml)

• After initial care, or when no airway, breathing or circulatory problems are present: antihistamines, corticosteroids can be administered (usually IV or IM) - secondary care

Diabetics 

Diabetes is a disease that affects the regulation of blood glucose, leading to dangerously high blood sugar levels (see systemic diseases related to dentistry for more detail). Let's focus on the type 1 diabetic as an example. Insulin deficiency, requires life long insulin therapy to be administered, for example, when eating a meal, simply speaking, this allows the intake of blood sugar into the muscles and regulate levels. However, if the meal is missed or too much insulin is administered, can lead to dangerously low blood sugar levels, known as hypoglycaemia, a recognised medical emergency. In addition, anxiety and stress, which many people associate with going to the dentist, can (not always) exacerbate a low blood sugar.

Therefore, if a patient is at an increased risk of hypoglycaemia, appointments can be  booked in the morning and ensure the patient has had food prior, with the correct dose of insulin (Type 1). Note: other medications can increase the risk of hypoglycaemia and will be cover in the pharmacology topic area.

Diabetic patients are also at increased risk of delayed healing and being immunocompromised, especially if the diabetes is poorly controlled. Using aseptic techniques could be an option for some procedures and ensure high standards of infection control.

Symptoms of hypoglycaemia can include:

• Confusion/Aggression
• Slurred speech
• Lethargy
• Unconsciousness
• Blurred vision
• Shaking trembling

Management:

If the patient is still awake they can be given an oral glucose; drink or food (15-20g/ 3-4 glucose tabs); however, if the patient becomes unconsciousness or their swallow is impaired, the clinician will administer glucagon intramuscularly:

• 1mg adult
• 0.5mg <25kg or < 8 years old)
• An ambulance should be called [1]

Prevention: Pre-operative management

Blood glucose levels can be monitored to gage if patient can undergo procedure - levels below 5.0 mmol/L, patients can have some glucose administered orally.

Patients are generally safe to treat if their blood sugar level is 5-15mmol/L.

Glycosylated HbA1c is a useful marker for how well the diabetes is controlled and can be tested prior to oral surgical procedures e.g. implants. Usually advised to keep levels at 6.5% (48mmol/ mol) or lower.

Post-operative management

Antibiotics can be considered when patients have poorly controlled diabetes or have undergone a difficult surgical procedure.

Epileptic Seizures 

Seizures are transient abnormal or excessive neuronal activity. They can be focal, generalised or unknown, associated with or without motor symptoms, and awareness can be impaired.

Increased stress may cause a seizure![3] This is important to consider as undergoing a surgical procedure which may put stress on patients.

We should enquire about the, nature, degree of control, timing and precipitation (if known) of at least the last three seizures. Symptoms of seizures could include:

• Jerking movements of limbs
• Rigidity
• Sudden collapse or loss of consciousness
• Noisey breathing
• Tongue may be bitten
• Frothing at the mouth
• Patient may become incontinent

Management:

The patient should not be restrained and the environment around them should be made safer e.g. remove all sharps near the patient.

Ensure that oro-mucosal midazolam is available and administer if patient has 3 or more siezures in the last hour or a seizure lasting 5 minutes or more. An ambulance should be called if there is difficulty monitoring the vital signs and airway of the patient. [1].

Common Midazolam dosage:

• 1-5yrs: 5mg
• 5-10yrs: 7.5mg
• >10yrs: 10mg

Note: Dependent on the case and procedure to be carried out, almost a a preventative option, IV sedation may be carried out due to the anticonvulsant effects.

Adrenal crisis 

Current guidance for those on steroid therapy: steroid cover, if the patient is taking >7.5 mg of prednisolone or the equivalent to prevent an adrenal crisis. Symptoms of this medical emergency include:

• Pallor (Paleness)
• Collapse
• Low blood pressure and Dizziness 
• Vomiting & or Diarrhoea  

Management:

An ambulance should be called, patient should be laid flat and 15/L oxygen per minute should be provided.

General: Healing of wounds may be compromised alongside increased risk of infection.

Note: Addisons disease.

Respiratory disease

Chronic Obstructive Pulmonary Disease (COPD), Asthma and respiratory tract infections are commonly seen in patients attending the dentist. Elective oral surgery should be differed in patient’s are experiencing an acute exacerbation of their respiratory disease. It should also be noted that aspirin and NSAIDS may induce an asthma attack, so worth asking the patient about their experience when taking these, before prescribing them.

COPD

COPD is characterised by reversible airflow limitation, this is almost exclusively caused by smoking. It is progressive and is associated with persistent lung inflammation. COPD is a term that encompasses chronic bronchitis and emphysema. 

Patient positioning is key, to allow the patient to adequately breathe.

Asthma 

Risk of airway obstruction via bronchospasm; symptoms include: 

• Breathlessness
• Expiratory Wheeze
• Inability to complete sentences in one breath

Management

Use of salbutamol (short acting beta agonist SABA - blue inhaler) with spacer if necessary, if the patient is suffering from an asthma attack. Usually 2 puffs (100 micrograms/ puff) is administered initially. Repeated puffs can be given if no improvement shown. Up to 10 puffs e.g. 1 puff every 30secs or 2 puffs every minute can be given. Repeat after 10-15mins if still no improvement. Call an ambulance if response is unsatisfactory.

Cardiovascular problems [3]

Cardiovascular problems are common in the western population and will be encountered by every dental practitioner at some point. The most common conditions are, ischaemic heart disease (IHD), hypertension, cardiac failure and valvular heart disease. 

Hypertension

Hypertension is a constantly raised blood pressure due to increased arteriolar resistance [3]. 9/10 cases of hypertension are due to essential hypertension, with no predisposing cause ("primary"), occasionally hypertension can be secondary to other conditions e.g. renal disease or diabetes mellitus [3]. A sustained blood pressure of >140/90 mmHg (mm of mercury) is considered hypertensive. 

If blood pressure (BP) is more than 160/100 mmHg, postponing certain treatments may be recommended until BP is better controlled or IV sedation may be helpful. There is a risk of mortality associated with hypertension and it is known as, the silent killer. This is often due to complications of hypertension on the cardiovascular health of the patient e.g. stroke and myocardial infarction (heart attack) etc.

If the patient has angina, a glyceryl trinitrate spray may be prescribed and we should ensure the patients brings it to appointments.

Ischaemic heart disease

Generally speaking IHD, is a reduced blood flow to the heart itself. This could be caused by atheromatous plaques in the coronary arteries, obstructing blood flow. This can obviously lead to severe problems.

If a patient has had a myocardial infarct or coronary artery bypass graft (CABG) or coil or stent procedure, or brittle angina, in recent months (3−6), elective extractions should be delayed. 

Myocardial Infarction

Cardiac emergencies can have varying symptoms but more commonly there is tightness or heaviness in the chest, accompanied by pallor (paleness) and sweating pain can often radiate to the jaw and left arm. 

Management:                                       

Two activations of GTN can be sprayed sublingually, 300mg of Aspirin can also be given if the patient is not allergic [1]. Oxygen can also be given to the patient if there are no contraindications. 

Patients at risk of infective endocarditis

This category of patients include: Previous history of infective endocarditis, cardiac defects, mitral valve regurgitation, and patients with prosthetic valves (any damage to heart tissue) – Consult with cardiologist if antibiotic prophylaxis is indicated, as it is not currently routinely given to all patients. 

Patients should be warned about symptoms of infective endocarditis e.g. progressive malaise (feeling of discomfort/illness), fever, pallor (paleness), fatigue, Janeway lesions on palms and soles of feet, splinter haemorrhages (tiny blood spots appearing below nails) and Osler’s nodes on distal fingers.

Antibiotic prophylaxis

The antibiotics used as prophylaxis for patients at risk of infective endocarditis currently included Amoxicillin, Clindamycin and Azthiromycin. Note: antibiotics being used are always reviewed and may be subject to change.

Patients should be encouraged to have good oral hygiene!

Stroke 

Patients with hypertension and other CVD are at increased risk of stroke. Symptoms are clear from the following mnemonic: FAST

Face, Arms, Speech slurred, and Time. 

Management:

Nil By Mouth!

Nothing should be given by mouth, this is because strokes can be due to ischaemia (blockage) or haemorrhages (escape of blood from a ruptured vessel) and since we don’t know the cause of the stroke in primary care it would be best to leave it in the hands of our specialist colleagues who would do CT scans and treat accordingly.

Oxygen can be given to the patient and an ambulance should be called immediately as time is very important!

Anaemia

Haemoglobin (Hb) level, adults:

• Female: < 120g/L (<12g/Dl)
• Male: <140g/L (<14g/Dl)

This is the one of the most common haematological disorders seen in medicine. There are many risks, causes and types e.g. low vitamin B12, or iron deficiency (see systemic disease topic area).

Sickle cell anaemia

This is an inherited blood disorder where red blood cells become sickle shaped, which can be triggered by cold, infection and hypoxic conditions (low oxygen availability). The sickle shaped cells don't flow as well through the vessels and areas of ischemia (temporary blockage of blood vessels) can occur; characterised by severe pain, usually the extremities e.g. in hands and feet. Furthermore, acute chest syndrome can occur which could be fatal in hours if not dealt with. Non-pharmaclogic management in practice can include oral hydration, heat, massage, and various cognitive-behavioural and self-relaxation techniques [4] if Oxygen saturation is below 95% oxygen therapy should be offered [4].

Patients at Increased risk of post-operative bleeding  

It is not always possible to predict if a patient will bleed excessively post-operatively; however, taking the patient’s medical history and a history of previous experience with certain procedures, alongside carrying out a thorough examination, targeted towards detecting haemostatic defects, are the best aids to predict post-operative bleed [5] 

Haemostatic disorders [3]:

Patients are at risk of post-operative bleeding if they suffer from a haemostatic disorder and this could be life threatening. They may take significantly longer to achieve haemostasis, this is mainly due to defective or reduced levels of coagulation factors.

Examples of haemostatic disorders include:

• DIC (Disseminated intravascular coagulation)   
• Haemophillia A, (Factor VIII)
• Haemophillia B, (Factor IX)
• Von willibands  

Management

• Patients with disorders of haemostasis may require liaison with a hematologist prior to underground any surgical procedure. If unsure, request the patient has a blood test to screen for any underlying medical conditions.
• The patient may need to be treated as an in patient
• Factor VIII levels between 50-75% are required as a minimum prior to treatment commencement. 
• Inferior alveolar nerve blocks should be avoided where possible.
• Local or Systemic Haemostatic measures may be required e.g. Tranexamic acid.

Liver disease [3]

There are many causes and types of biases, but it is important to be thinking, what functions does the liver carry out and if affected how does this impact treatment?

• Increased risk of bleeding – the Liver is involved in producing coagulation factors which are important to helping the blood clot.
• Impaired drug metabolism – the Liver produces many enzymes that help metabolize drugs in the body to make them easier to excrete. 
• Risk of being immunocompromised
• Cross infection risk e.g. Hepatitis B and C

Pre-operative management

Liver disease such as alcoholic hepatitis, chronic viral hepatitis and biliary cirrhosis may require liaison with the physician pre-operatively with blood tests, liver profile, coagulation screen and FBC (full blood count) carried out.

Post-operative management 

• Haemostatic agents can be applied to socket to aid haemostasis e.g. Surgicel.
• Cross infection control (as for all patients), and the clinician should be immunised against Hep B.

Kidney disease

The kidney is another incredible organ; in addition to its excretory/ filtration function, it helps regulate BP, involved with vitamin D metabolism (think bone health), and produces EPO which regulates red blood cell production (also note: platelets).

Pre-operative management:

• Patients with chronic kidney disease may require pre-operative liason with their physician for a renal profile and FBC. 
• Patients with kidney disease may be undergoing dialysis and ideally treated the day after dialysis.
• They may also be at risk of increased bleeding as kidney disease is associated with platelet dysfunction, and the patient may be taking anticoagulants. 
• Patients may be immunocompromised and thus they may require antibiotic cover. 
• The kidney is involved in excretion of drug metabolites so care should be taken when prescribing, as this ability of excretion may be diminished.

Post-operative management

• Haemostasis can be achieved/aided using local measures such as Surgicel, Tranexamic acid etc.

Other causes of bleeding include:

• Recent or current chemotherapy/radiotherapy to head & neck <3 months prior or total body irradiation <6 months prior. This can lead to Pancytopenia including reduced platelet numbers. 

• Haematological malignancy or myelodysplastic disorder, Idiopathic thrombocytopenic purpura (ITP). This leads to impaired coagulation or platelet function (even in remission) and reduced platelet numbers. 

• Advanced heart failure is also associated with liver failure, thus leading to a reduction of platelet numbers and coagulation factors.

Platelets

Note: Thrombocytopenia. If platelet count <50 x 10^9/L surgery is generally contraindicated, and a platelet transfusion is indicated [6].

National guidelines for INR

An INR is usually needed when patients are taking Warfarin (see pharmacology section). National guidelines permits clinicians to do 3 routine extractions or 1 surgical if patients INR is 4 or less. 

However it should be noted INR is not always affected by anticoagulants e.g. the NOAC family, so care should still be taken even with INR in normal ranges. See SDCEP guidelines - third party reading.

Medications affecting haemostasis:

Antiplatelets

Irreverisible

• Aspirin 
• Prasurgel 
• Clopidogrel 

Reversible 

• Dipyridamole 
• Ticagrelor

Anticoagulants

Warfarin (Affects INR) – long term 

• Works like a vitamin K antagonist. Antagonizes factor II, VII, IX and X. 

Heparin + Low molecular weight heparins (LMWH) (Affects INR) – Short term

• Potentiates antithrombin III on thrombin and factor Xa

Factor Xa inhibitors 

Novel Oral AntiCoagulants (NOACs) 

• Rivaraxoban
• Apixaban

For more information about interaction, in depth mechanism and the clotting cascade please visit the pharmacology lecture on anticoagulants and antiplatelets. 

Assisting haemostasis

Local measures for assisting haemostasis include tranexamic acid, surgicel (oxidized cellulose), bone wax and gelfoam. Some of these products are derived from animals; therefore, this should be communicated clearly to patient, as some may be against the use of certain animal products.

Local haemostatic measures

Bite/pressure pack: Apply pressure on site of bleeding  

LA w/ vasoconstrictor: constricts blood flow 

Suturing: Over the socket, keeps hemostatic agent and blood clot in place. Brings mucosa into close apposition for primary healing where possible

Surgicel: resorbable, oxidised regenerated cellulose. Binds Hb to oxycellulose to expand into a gelatinous mass. 

Gelfoam: Absorbs blood, and releases thromboplastin. Provides structural support for clot. Liquefies after 1 week. resorbabs after 4 weeks.  

Bone wax: A mixture of beeswax + paraffin + isopropyl palmitate. Used as a mechanical sealant to coat the bleeding surface of bone. Fairly unresorbable and associated with an increased risk of foreign body reaction.  

Tranexamic Acid mouth wash: uisually in a 5% mouthwash. 5-10ml rinse for 2 mins, QID 2-5 days. First dose 15-20mins post XLA. Also available as tablets  

Mechanism of action: Binds to plasminogen, therefore preventing the activation of plasminogen to plasmin, leading to a reduction in the breakdown of clots.

Thrombin: same action as endogenous thrombin (fibrinogen --> fibrin). Promotes platelet aggregation and can be used in combination w/ surgicel  

Disorders of Bone

Is the bone going to be dense, brittle, or fragile? Therefore, how difficult is the procedure going to be and what is the risk of fracture? Note: some bone disorders are treated with bisphosphonates.

Osteoporosis

Deficiency of bone matrix (ratio of organic and inorganic remains unchanged). Patients may also be taking bisphosphonates.

The bone is more at risk of fracturing. 

Note: Osteomalacia is a ratio deficiency = "soft bone". Associated with vitamin D deficiency e.g. Rickets.

Note: Osteopetrosis is a disease causing increase in bone density, but still weak and at risk of fracture. Associated with anaemia due to decreased marrow activity.

Paget’s disease of bone

Paget’sdisease of bone interferes with your body's normal recycling process leading to progressive enlargement. Over time, the disease can lead to pain (compression of nerves), and large deformed boney areas. There is an association with heart failure, due to the hypervascularity or the bone. Extractions are usually surgical and there is an increased risk of osteomyelitis..

Osteogenesis imperfecta

Rare autosomal dominant bone disorders, causing a defect in collagen formation. There are many categories with variable bone fragility [7]. Note: heart valve problems may also be seen with these disorders.  

Hyperparathyroidism

Parathyroid gland produces excess PTH which causes hypercalcemia and can affect brittleness of bone. 

See systemic disease topic area for more detail on bone disorders.

Sedation and anxiolysis

This is an important topic to discuss prior to starting any surgical procedure as it can help minimise anxiety peri-operatively. The patient’s psychological state should be considered in the pre-operative assessment to gage if they are capable of undergoing the procedure.

Traumatic dental experiences can also deter patients from undergoing any further dental examination/ treatment. It should also be noted that not all cases are appropriate from sedation, some contraindications include:

• Allergy to benzodiazapenes
• Pregnancy 
• Severe Chronic Obstructive Pulmonary Disease (COPD)

Caution should be taken when sedating the following category of patients:

• Liver/renal disease
• Sickle cell disease
• Extremes of age
• Myasthenia gravis
• Psychiatric disease

High risk of MRONJ category (1%)

See Bisphosphonates lesson for more detail (pharmacology topic area)

Things to consider:

• History of taking Bisphosphonates - Dose and route of administration (oral/ IV)
• Oral/IV bisphosphonates with steroids  
• Oral/IV bisphosphonates >5 years  
• Anti-angiogenics 
• Denosumab (RANKL Inhibitor) 
• Cancer diagnosis

In the case of patients in the high risk for getting MRONJ category, alternative treatment e.g. RCT, coronectomy or referral should be considered.

Extremes of age

This is important to consider when treatment planning and prescribing. Certain drugs are contra-indicated in children/under 16s e.g. Aspirin.

Physiological changes with old age include:

• Thinning mandibles and bone becoming more brittle= increased risk of fracture.
• Diminishing Kidney and liver function – the dosage should be prescribed according to BNF guidelines.

Psychiatric drugs

Selective Serotonin Reuptake Inhibitors (SSRIs), Selective norepinephrine Reuptake Inhibitors (SNRIs) and tricyclic antidepressants can cause xerostomia (dry mouth). This will make patients more vulnerable to caries, periodontal disease and oral infections e.g. candida.