Day case dental anaesthesia
Anaesthesia for dental surgery would routinely be considered a day case procedure. However, many patients may be scheduled for such procedures, occasionally by non-physicians, without appreciation for the impact of their comorbidity on the day surgery process. This case highlights a planned routine dental extraction in a patient with considerable comorbidity and discusses the suitability or not for this to be performed as a day case.
1 Assess a patient with complex comorbidity listed for an outpatient anaesthetic procedure
2 Acknowledge potential perioperative complications in an adult with congenital heart disease
3 Discuss the anaesthetic technique for such patients.
2A03
You are anaesthetizing for an adult dental day case in a dental hospital. An 18-year-old male presents for elective removal of all four wisdom teeth. He weighs 60 kg. He has Eisenmenger’s syndrome.
Eisenmenger’s syndrome is a syndrome of right-to-left cardiac shunt as a result of pulmonary hypertension. The initial shunt is left to right, due to an intraventricular, intra-atrial, or aortopulmonary defect. Over time, pulmonary hypertension develops and is described as Eisenmenger’s syndrome when the shunt reverses and becomes right to left or bidirectional.
The patient may be cyanosed, dyspnoeic, and polycythaemic, and he may have signs and symptoms of ventricular strain. Patients with Eisenmenger’s syndrome are at increased risk of supraventricular arrhythmias, sudden death, thrombosis, bacterial endocarditis and clots, and air emboli. He may also be warfarinized. Decreasing afterload will increase shunt and worsen hypoxia.
You would involve an anaesthetic consultant immediately.
You need to break down this case into components relating to the surgery, clinical condition, suitability of the location, and mode of anaesthesia. These need to be discussed with the dental surgeon and the safest course of action followed.
This will have been carefully considered by the referring dentist and by the accepting surgeon, but it does no harm to ask. The dental radiographs can be reviewed and surgery reconsidered. If the patient has had pain and infection around impacted wisdom teeth, then they are at risk of bacterial endocarditis, and the dental infection is likely to return in the future. The shunt will continue to worsen with time, so delaying the procedure may mean the same procedure is carried out when patient fitness has worsened.
It may be that the wisdom teeth may be relatively straightforward to remove under local anaesthetic block, avoiding the need for general anaesthesia. The teeth may not all need to be removed at the same time, though the patient is keen to limit the extractions to one visit. Significant anxiety on the patient’s part will increase circulating catecholamines and increase the risk of arrhythmia, decreasing cardiac function. This may be attenuated by careful conscious sedation.
Whilst two teeth look to be very straightforward to extract, two look particularly difficult, and having a general anaesthetic will make the procedure significantly easier for the surgeon. The additional time to remove the straightforward teeth will be relatively small, so, on balance, it is probably safer to remove all four teeth in one operation, rather than two. This was the reason for his addition to a general anaesthetic dental list.
This gentleman has regularly been followed up by the local cardiology services, and a recent clinic letter should be available. If there have been any changes or deterioration since his last cardiac review, then a discussion with the patient’s cardiologist is advisable, in case a change in drug management would improve cardiac function. This gentleman saw his cardiologist 2 weeks ago and has not noticed any changes in his condition in the last year.
Any operating location outwith a theatre suite is regarded as remote. This would include a physically distant single theatre in a large hospital complex or a single theatre in a separate hospital. The authors regard any location where it is not possible to receive qualified anaesthetic help by shouting from the theatre door should be classified as remote for the purposes of anaesthesia.
This dental hospital may be on a larger hospital site or a number of miles from general hospital critical care facilities. Whilst the standard of care should not differ from any other operating theatre, this gentleman has a higher than average chance of perioperative complications and help may be required. It would be advisable to carry out this gentleman’s procedure in a theatre suite where immediate help would be available, and he should be referred to the nearest maxillofacial surgery unit. A general anaesthetic should not be carried out in this remote location.
The authors feel that, whilst this may be uneventful, should perioperative problems develop, the level of support immediately available may not be sufficient. This gentleman would be best treated in a maxillofacial unit within a theatre suite environment.
This anaesthetic requires being carried out carefully, with attention to managing systemic and pulmonary vascular resistance (PVR). A drop in systemic vascular resistance (SVR) will decrease pulmonary perfusion by increasing right-to-left shunt. A rise in PVR will also increase right-to-left shunt and worsen oxygenation. PVR is difficult to reduce, and SVR is the variable that is likely to change the most with administration of anaesthesia. The circulating volume needs to be maintained, and dehydration should be avoided. Bradycardia and high-pressure IPPV should be avoided. Where possible, techniques involving spontaneous ventilation should be used.
The choice of induction agent is probably less important than the familiarity of the anaesthetist with the agent and their ability to administer it in a safe and controlled manner.
Analgesia will be provided by the dentist’s administration of local anaesthetic. Use of an octapressin-containing local anaesthetic solution, rather than an adrenaline-containing solution, should be considered to avoid adrenaline-related tachycardia and arrhythmia. Careful use of short-acting opiates, such as fentanyl, to dampen any stimulation from airway manipulation by the dental surgeon or anaesthetist would be advisable.
This procedure requires sharing of the airway and involves potential blood loss into the mouth, but this does not necessarily require intubation, and the procedure can be safely carried out using a flexible LMA. A throat pack can be used to secure the airway, though precautions must be in place to ensure it is not left in situ at the end of the case.
The authors would aim to use a spontaneously ventilating technique with a flexible LMA, if possible, to avoid increasing PVR. If IPPV is unavoidable, then low inflation pressures should be used. Nitrous oxide increases PVR, PONV, and the size of any air emboli, and it should therefore be avoided.
Standard monitoring of ECG, SpO2, end-tidal carbon dioxide (ETCO2), and end-tidal agent monitoring would be necessary. A secure IV access is also needed. The authors would use intra-arterial BP monitoring in this situation.
◆ High oxygen levels may cause pulmonary vasodilation
◆ Vasopressors, such as the alpha adrenergic agonists metaraminol, phenylephrine, and noradrenaline, can be used to maintain SVR. They may, however, also increase PVR and cause bradycardia
◆ Hypovolaemia should be avoided, and antithrombotic prophylaxis should be considered
◆ Anticholinergics, such as atropine and glycopyrrolate, can be used to prevent bradycardia
◆ Histamine-releasing drugs may increase PVR
◆ Special care needs to be taken to ensure air bubbles are not introduced during IV administration of drugs and fluids due to the risk of paradoxical embolus
◆ Thromboprophylaxis may need to be considered if polycythaemia is present and mobility is limited.
◆ Cardiology and Haematology specialists may need consulted.
Until 2008, all patients like this in the UK would have received antibiotic prophylaxis. The Working Party of the British Society for Antimicrobial Chemotherapy guidelines in 2006 and NICE guideline CG64 in 2008, whilst recognizing this population group as being at higher risk of developing bacterial endocarditis, stated they would not recommend antibiotic prophylaxis in this particular situation. These recommendations are supported by guidelines from the American Heart Association and European Society of Cardiology.
The issue is that available evidence suggests that dental treatment per se does not increase the risk of infective endocarditis.
The Working Party of the British Society for Antimicrobial Chemotherapy recommends prophylaxis for dental procedures only for those patients with a history of previous endocarditis, cardiac valve replacement, or those with a surgically constructed systemic or pulmonary shunt or conduit.
If this gentleman was undergoing surgery at a site that was infected, e.g. one or more of the teeth to be removed were infected at the time of surgery, then these recommendations suggest using antibiotics that cover the organisms that cause infective endocarditis. It is also important to note that these groups differ in their recommendations relating to antibiotic prophylaxis for certain non-dental surgical operations.
If the procedure is carried out first on the morning theatre list, there are no surgical or anaesthetic complications, and he returns to his preoperative state quickly, there is the potential for same-day discharge. His physiology would need to have returned to baseline; he would need to meet all standard discharge protocols, and he would need to live close to the hospital.
The authors, however, would prefer such a patient to remain overnight in hospital for observation, whilst recognizing there may not be an evidence base for this recommendation.
Summary
Current practice has moved dental anaesthesia away from isolated sites towards theatre complexes such as dental hospitals and hospitals with dental services.
Due consideration must be given to the suitability of some cases to be done as day cases, as there may be significant comorbidities.
Consideration must be given as to whether cases can be done entirely as local anaesthetics, with or without sedation, or as a full general anaesthetic.
Antimicrobial chemoprophylaxis may still be required for some patients.
Habib G, Hoen B, Tornos B, et al. (2009). Guidelines on the prevention, diagnosis, and treatment of infective endocarditis (new version 2009): the Task Force on the Prevention, Diagnosis, and Treatment of Infective Endocarditis of the European Society of Cardiology (ESC). Endorsed by the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) and the International Society of Chemotherapy (ISC) for Infection and Cancer. European Heart Journal, 30, 2369–413.
Jayaraman L, Sethi N, and Sood J (2009). Anaesthesia outside the operating theatre. Update in Anaesthesia, 25, 37–41.
National Institute for Health and Clinical Excellence (2008). Prophylaxis against infective endocarditis (CG64). Available at: <http://guidance.nice.org.uk/CG64>.
Solanki SL, Vaishnav V, and Vijay AK (2008). Non cardiac surgery in a patient with Eisenmenger Syndrome—Anaesthesiologist’s challenge. Journal of Anaesthesiology Clinical Pharmacology, 26, 539–40.