Saturday, September 17, 2011

Management of medically compromised patients in the Oral surgery

Oral surgery in the medically compromised patient

Introduction
Patients who require an oral surgical procedure will have their medical status questioned as a matter of routine during the history taking. Certain conditions have a direct bearing on the management and treatment of these patients, which may have to be altered or modified as a result. Thus the treatment plan may have to be modified for the patient's safety.
Most medical conditions do not interfere with minor oral surgical procedures carried out under local anaesthetic. The major problems are with patients who have bleeding tendencies, allergies, are on corticosteroids or have cardiac disease.
Those requiring general anaesthetic will be treated in the secondary care system under the supervision of a consultant anaesthetist.
Not only can systemic disease influence the oral management of a patient, but systemic disease may arise from the mouth, usually as a result of infection. An example of this is infective endocarditis arising in a patient with valvular or other cardiac disease; immune compromised patients, such as those taking cytotoxic chemotherapy, are also at special risk of infection. More-over, a number of acute medical emergencies may arise while oral surgical procedures are being carried out and the surgeon must have the necessary agents available for the appropriate management of the patient. The main systemic diseases that impact on the practice of oral surgery are listed in following table, and these will be discussed in turn.
Systemic disease and oral surgery
Blood disorders: haemorrhagic disease
Cardiovascular disease
Endocrine disease
Liver disease
Neurological disease
Pregnancy
Radiotherapy
Renal disease
Respiratory disease

Blood disorders
Haematological disease, particularly anaemia, is not uncommon. Except in severe cases and those requiring general anaesthesia, anaemia is not a significant problem because blood loss during minor oral surgical procedures should be controlled and not excessive.
A number of bleeding disorders can occur and the specific management of postextraction haemorrhage will be considered in detail in future posts. In addition, it should be noted that aspirin is being taken by an increasing number of patients for prophylaxis against thrombotic disease such as coronary artery disease or cerebrovascular thrombotic incidence. Normally, a dose of 75 mg daily is prescribed, which has the desired effect of reducing platelet adhesiveness. In theory, this should also cause more bleeding after oral surgery, but in practice it seldom seems to have a significant effect. Occasionally, continued oozing may prompt haemostatic measures such as suturing or use of regenerated oxidised cellulose but in most cases firm pressure is all that is necessary.
When patients are taking higher doses of aspirin for chronic pain (e.g. patients with osteoarthritis or rheumatoid arthritis), then more major oral surgery may require the use of alternative analgesics for about 2 weeks before surgery, as the effects on platelets might prove more troublesome in these circumstances.
Patients taking anticoagulants, such as warfarin, for cardiac arrythmias or those with prosthetic heart valves, should have their INR (International Normalised Ratio) estimated on the day of surgery. A higher INR can be accepted before minor oral surgical than before general surgery. Some suggest that an INR of <4 can be accepted, but most oral surgeons would wish the INR to be between 2-3 for elective procedures other than single tooth extractions. Haemostasis should be secured with local measures including Surgicel®, suturing and pressure packs.
Surgeons must also be aware of the effect of prescribed drugs on anticoagulated patients. Most antibiotics and some antifungals will enhance the anticoagulant effect of warfarin, and non-steroidal anti-inflammatory drugs such as aspirin not only enhance the activity of warfarin but risk more severe bleeding from the stomach by their action on the gastric mucosa.
Cardiovascular disease
From an oral surgical viewpoint, patients with cardio-vascular disease can be considered in two groups.
Those with vascular disease
Hypertension is probably the most common consequence of peripheral vascular disease. Patients may be taking a variety of medications, ranging from diuretics to beta-blockers, calcium-channel-blockers or angiotensin-converting-enzyme (ACE) inhibitors. In general terms, treatment of the hypertensive patient will be largely unaltered other than under a general anaesthetic. Most dentoalveolar surgery can be carried out with no problems under local anaesthesia, although adrenaline (epinephrine)-containing local anaesthetics are known to cause a reduction in the blood potassium level and, in patients taking potassium-losing diuretics, an adrenaline (epinephrine)-free local anaesthetic may be preferred. This is a theoretical risk.
Those with cardiac disease
Those with cardiac disease can be conveniently considered under two headings.
Valvular disease
Although rheumatic fever is now extremely rare, valvular disease of the heart is still seen in the older population as a consequence of its effects on the valves. Although damage is not invariable, these patients are regarded as 'at risk' unless there is proof to the contrary. This should include those with developmental septal defects and those with prosthetic heart valves following cardiac surgery.
Patients with cardiac pacemakers are not at risk and anti-biotic therapy is not required. The remainder are at risk of endocarditis as a result of bacteraemia, which will be resultant upon oral surgery. Antibiotic cover is, therefore, a preoperative requirement and the regime is dependent on whether the patient is being treated under local or general anaesthesia, whether the patient is allergic to penicillin and whether penicillin has been prescribed on more than one occasion in the previous month. Patients at a particular high risk are those who have had a previous episode of endocarditis. The appropriate regime for managing these patients is listed in table below.
Prevention of endocarditis1 in patients with heart-valve lesion, septal defect, patent ductus, or
prosthetic valve
Dental procedures2 under local or no anaesthesia,
patients who have not received more than a single dose of a penicillin in the previous month, including those with a prosthetic valve (but not those who have had endocarditis), oral amoxicillin 3 g 1 h before procedure; CHILD under 5 years quarter adult dose; 5–10 years half adult dose

patients who are penicillin-allergic or have received more than a single dose of penicillin in the previous month, oral clindamycin3 600 mg 1 h before procedure; child under 5 years quarter adult dose; 5–10 years half adult dose

patients who have had endocarditis, amoxicillin + gentamicin, as under general anaesthesia

Dental procedures2 under general anaesthesia,
no special risk (including patients who have not received more than a single dose of a penicillin in the previous month), either i.m. or i.v. amoxicillin 1 g at induction, then oral amoxicillin 500 mg 6 h later; CHILD under 5 years quarter adult dose; 5–10 years half adult dose

or oral amoxicillin 3 g 4 h before induction then oral amoxicillin 3 g as soon as possible after procedure; CHILD under 5 years quarter adult dose; 5-10 years half adult dose

or oral amoxicillin 3 g + oral probenecid 1 g 4 h before procedure

Special risk (patients with prosthetic valve or who have had endocarditis),
 i.m. or i.v. amoxicillin 1 g + i.m. or i.v. gentamicin 120 mg at induction, then oral amoxicillin 500 mg 6 h later; CHILD under 5 years amoxicillin quarter adult dose, gentamicin 2 mg/kg; 5–10 years amoxicillin half adult dose, gentamicin 2 mg/kg

patients who are penicillin-allergic or who have received more than a single dose of a penicillin in the previous month,
either i.v. vancomycin 1 g over at least 100 min then i.v. gentamicin 120 mg at induction or 15 min before procedure; CHILD under 10 years vancomycin 20 mg/kg, gentamicin 2 mg/kg

or i.v. teicoplanin 400 mg + gentamicin 120 mg at induction or 15 min before procedure; CHILD under 14 years teicoplanin 6 mg/kg, gentamicin 2 mg/kg

or i.v. clindamycin3 300 mg over at least 10 min at induction or 15 min before procedure then oral or i.v. clindamycin 150 mg 6 h later; CHILD under 5 years quarter adult dose; 5–10 years half adult dose
1 Reproduced from the British National Formulary (March 1997), with the permission of the British Medical Association and the Royal Pharmaceutical Society of Great Britain.
2 Dental procedures that require antibiotic prophylaxis are: extractions, scaling and surgery involving gingival tissues. Antibiotic prophylaxis for dental procedures may be supplemented with chlorhexidine gluconate gel 1 % or chlorhexidine gluconate mouthwash 0.2%, used 5 min before procedure.
3 If clindamycin is used, periodontal or other multistage procedures should not be repeated at intervals of less than 2 weeks.

Ischaemic heart disease
Patients at particular risk are those with severe hypertension, those with angina or those who have had a previous myocardial infarction. Anxiety or pain can cause an outpouring of adrenaline, which can increase the strain on the heart and also precipitate dangerous arrhythmias. The patient should, therefore, be exposed to minimum stress and prescribed sedation if required.
The most effective agent for local anaesthesia is lidocaine (lignocaine) 2% with adrenaline (epinephrine). Doses of local anaesthetics should be kept to a minimum and treatment sessions should not be prolonged. If it is unavoidable, general anaesthesia should be given by an expert anaesthetist in a hospital setting, because cardiovascular disease is the chief risk of death under anaesthesia.
A number of measures should be considered when treating patients in an outpatient environment under local anaesthesia. Patients should be advised to continue their normal medication before and after procedures. Patients should bring their glyceryl trinitrate (GTN) spray to the surgery, if they use one, because they may wish to use it prophylactically. Oxygen should be available on a continuous flow delivery system and staff should be trained in the appropriate care for the collapsed patient.
Where possible, surgical treatment is best deferred for 3-6 months after myocardial infarction, depending on the severity of the attack and the patient's rate and degree of recovery.
Endocrine disorders
A number of endocrine disorders can complicate the management of the patient undergoing minor oral surgery. The most prevalent of these conditions is diabetes mellitus, which can occur in the insulin-dependent form or in the non-insulin-dependent, maturity-onset form. In addition, an increasing number of patients take corticosteroid drugs for the management of autoimmune conditions. The management of these groups of patients will now be discussed.
Diabetes mellitus
If oral surgery requires a general anaesthetic, the requirements of preanaesthetic starving and the difficulties with postoperative food intake will need appropriate management. This needs to be carried out on an inpatient basis in cooperation with the patient's physician and using a balance of dextrose infusions and soluble insulin.
Under local anaesthetic, patients should be encouraged to maintain their normal regime with regard to eating and insulin injections. Effort should be made not to delay treatment such that the normal dietary intake is disrupted.
Diabetic patients have a compromised response to infections. Certain procedures may, therefore, warrant an antibiotic prescription to cover them over the initial healing period. For the straightforward extraction in a well-controlled patient, however, this is not necessary, particularly where good oral hygiene can be relied upon.
Certain non-steroidal anti-inflammatory drugs have an effect on blood sugar levels and paracetamol, with or without codeine, may be a wiser analgesic choice.
Corticosteroid treatment
Corticosteroids have important effects when given in sufficiently large doses, and these include depression of adrenocortical function, which will lead to collapse under stress. Depression of the inflammatory and immune responses may lead to an increase in opportunistic infections and impaired wound healing.
The need to give additional steroids for those patients taking systemic corticosteroids, or having used them in the previous 2 years, is controversial. Where clinical concerns exist regarding the risk of hypotensive shock, patients should be treated by increasing oral steroid therapy or by intravenous or intramuscular hydrocortisone.
Liver disease
Normal liver function is essential for production of several blood-clotting factors and for the metabolism and detoxification of many drugs. Viral disease also has implications in terms of cross-infection. It is important to assess coagulation defects preoperatively to ensure that adequate haemostasis will occur, and to be aware of the possibility of reduced drug break-down when administering or prescribing agents. The British National Formulary contains valuable information on prescribing for such patients and should be consulted appropriately.
Neurological disease
The most significant neurological problem presenting routinely in minor oral surgical practice is that of grand mal epilepsy.
Most patients with epilepsy will be taking antiepileptic drugs such as carbamazepine or phenytoin for the control of the seizures. Oral surgery can be carried out under local anaesthesia without any problems if control is satisfactory and patients should be advised to continue their normal antiepileptic drug unchanged. If general anaesthesia is required, the anaesthetist should be made aware of the history to allow for the use of appropriate volatile agents for anaesthetic maintenance.
Pregnancy
Minor oral surgical procedures can be carried out during pregnancy, which, it should be remembered, is a physiological state. The potential risks to the mother and fetus are outlined below.
Oral surgical considerations in pregnancy
Risk to mother
increased gingivitis and epulis formation
risk of hypotension if supine
risk of hypertension
vomiting especially with general anaesthesia
aspirin may cause neonatal haemorrhage

Risk to fetus
radiography hazardous
respiratory depression with sedatives
tooth staining with tetracyclines
prilocaine rarely causes methaemoglobinaemia
some drugs are teratogenic

In the later stages of pregnancy, patients should normally receive treatment in a more upright position rather than supine because the weight of the fetus and uterus can interfere with blood return via the inferior vena cava.
Although radiographs in the region of the jaws do not cause direct irradiation of the abdominal area, these should be restricted to clinical necessity, as should all radiographs. Patients who have non-acute problems should defer radiographic imaging until after pregnancy. Protective shielding where radiographs are needed should be used as much for reassurance as for their actual benefit. In acute conditions, radiographs will often be necessary and patients should be reassured that the risk is minimal.
Prescription of drugs should be carefully considered and reference to the British National Formulary is necessary to allow a choice of drugs that have been proven safe during this period. Lidocaine (lignocaine) plus adrenaline (epinephrine) is an appropriate anaesthetic and some clinicians prefer to avoid prilocaine with felypressin, which may (in theory) have a mild oxytocic effect. During the first trimester of pregnancy, particular care should be taken with any prescription as this is the time when drugs administered to the mother can have the most serious consequences on the child's development.
Necessary dental treatment should continue during pregnancy, especially such measures as extraction of unrestorable, grossly carious teeth where delay could lead to acute pain and spread of infection. Prompt treatment under local anaesthesia may well avoid the need for later use of antibiotics and painkillers, and even the need for general anaesthesia where gross infection precludes the use of a local anaesthetic. For less urgent surgery, such as removal of wisdom teeth or periradicular surgery, it is better that the surgical treatment is carried out during the middle trimester of pregnancy or deferred until after the pregnancy.
Most pregnancies are trouble free, but if there are related problems surgeons should communicate with the consulting obstetrician if there is any doubt as to the appropriateness of dental treatment.
Renal disease
Renal disease is becoming more important to the dental surgeon as more patients are now receiving renal dialysis or renal transplantation. Patients receiving regular haemo-dialysis are heparinised before dialysis and haemostasis is impaired for 6–12 h thereafter. These patients are also at greater risk of carrying hepatitis viruses. Furthermore, the permanent fistula formation that is required for haemodialysis is susceptible to infection and antibiotic cover should be provided for these individuals.
In addition, the kidney is a major organ of excretion and many drugs may have reduced elimination leading to  possible toxic effects if renal function is impaired. The British National Formulary should be consulted before prescribing drugs for any patient with a history of renal disease.
Respiratory disease
Long-standing or severe obstructive pulmonary disease poses general anaesthetic problems not only because of the compromised gaseous exchange but also because of the possible related right-sided heart failure problems. The conditions most likely to cause chronic obstructive pulmonary disease are bronchitis, bronchiectasis and asthma.
Treatment that is to be carried out under local anaesthetic should be staged to reduce stress and fatigue. Asthmatic patients should be counselled to bring their salbutamol or corticosteroid inhalers to the surgery and to use them if the need arises. Salbutamol and oxygen should be kept in the surgery, with a suitable method of delivery as an emergency measure. Worsening of asthma can be related to non-steroidal anti-inflammatories and caution should be exercised in their prescription. 
Dental Management of the Medically Compromised Patient

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