Chapter 01

Adult mentally challenged patient for dental procedure

Dr. Vasanthi Vidyasagaran*

Department of Anaesthesiology, Kauvery Hospital, Chennai, Tamilnadu, India

*Correspondence: [email protected]

Dr. Vasanthy Vidyasagaran Muralidharan

PRE-OPERATIVE Chapters 1 and 2 – Learning from Experience

Anaemia-or-Hydrocele

Case 1: Mentally disabled patient with dental abscess

A 35-years old, mentally handicapped, well-built person, being cared by his mother, was admitted with suspected dental abscess, complaining of inability to feed for the past three days. He had no other medical illness.

The dentists were unable to examine the inside of his mouth as he refused to open it and was extremely uncooperative. They requested some sedation to examine his oral cavity. He was starved adequately.

On examination, he was very violent and uncooperative, probably in pain. Chest auscultation revealed few scattered bilateral crepitation. Vitals stable. There was a small visible external swelling on his left mandible. There was a suspicion that this could spread and worsen the situation compromising the airway. A 20 G intravenous line was started with a lot of difficulty.

Concerns:

  • Uncooperative, strong, agitated adult patient with difficulty in comprehension
  • No opportunity to examine the airway preoperatively
  • No investigations were possible.

The plan was to commence intravenous anaesthesia in the preoperative room itself, with emergency backup and then mobilize the patient into theatre, secure airway and proceed. Situation was explained to the care taker, and consent obtained.

Propofol iv 100 mg and midazolam 2mg.were given slowly watching over his respiration, and pulse. Pulse oximeter was used to monitor at this point. Airway was maintained with Ambu bag with high flow oxygen. Once he was asleep, he was quickly transferred to a trolley and wheeled into the operating table where the team was ready with adequate monitors and airway devices. He was further given oxygen and Sevoflurane. Airway was secured (nasal intubation) in a spontaneously breathing patient without use of muscle relaxant, as he was under adequate plane of anaesthesia. After securing the airway, confirmed with etco2, inj. atracurium 25 mgs was administered and ventilated. Throat was packed. Surgeons could now examine the patient.

Examination revealed a septic focus on his left lower molar and premolar teeth. They were extracted and the abscess curetted, good suction was done. Intravenous antibiotic cover was given. Patient was extubated at the end of procedure. Adequate analgesia with IV Paracetamol 1gm and IM Diclofenac 75 mg were provided. Patient woke up, comfortable and recovered well.

Case 2

A 30 year, young lady who was mentally handicapped from birth, was brought into dental outpatient clinic by her sister with a severe gum infection and multiple loose teeth. An oral examination revealed that she had very poor oral hygiene, multiple loose teeth and they had to be extracted. She was obese weighing 95 kg with a short neck.

Since there were multiple extractions and she was uncooperative due to back ground illness, the procedure was planned under general anaesthesia.

All her blood investigations were within normal limits. After premedication with IM Tramadol 50 mg and Inj. Glycopyrrolate 0.2 mg she was slightly sedated and cooperative.

Anaesthesia was induced with IV Propofol 150 mg and Suxamethonium 100mg was used as muscle relaxant. Trachea was intubated with a size 7 oral cuffed ETT. The throat was packed and the extractions were done.

  • Anaesthesia during the procedure was maintained with oxygen, nitrous oxide (50:50) and isoflurane. In normal anaesthesia practice, oral and maxillofacial surgeries are performed with a nasal intubation to facilitate space for surgeons in their area of surgery. However here, we chose to do oral intubation because:
  • Nasal intubation being more time consuming than oral intubation, may cause the obese patient to desaturate due to poor respiratory reserve.
  • Multiple loose teeth may be dislodged during the procedure with a risk of aspiration
  • Bleeding from tissue trauma may obscure vision during intubation.
  • It was only extractions and the surgeon could manage it quite well.

Patient recovered well with no perioperative issues. It is important that the surgeons are efficient and understanding in order to complete the procedure quickly.

Discussion

Anaesthesia for adult patients with mental retardation can be very challenging due to multiple problems. The term MR is used when an individual’s intellectual development is significantly lower than average and ability to adapt to environment is limited. The WHO recommends classifying them into Mild (IQ 50-69, mental age of 8-12 years), Moderate (IQ 20-49, mental age of 3-7 years) and severe MR (IQ 0- 19, mental age of 0-2 years).

Anaesthetic implications:

  1. First it is difficult to establish a rapport with the patient. This makes it tricky when dealing with patients with airway issues because they need to understand and cooperate during induction and extubation.
  2. Counseling the family is very important. Informed consent must be obtained from the person who is responsible for the patient.
  3. Preoperative assessment including physical examination may be extremely difficult in some patients. They may not also cooperate for investigations.
  4. Upper airway issues: Dental hygiene, loose teeth, caries, abscesses, macroglossia, enlarged tonsils, restricted mouth opening are some of the conditions that may be present which are of utmost importance to the anaesthetist.
  5. Other systemic illnesses may coexist: Cardiac anomalies, hypertension, lung diseases, neuronal diseases including seizures, and contractures. Inborn errors of metabolism may complicate the existing conditions.
  6. They may be on drugs which may interact with anaesthesia. Hence complete history from the care taker is essential. History of intake of anticonvulsants, antispasmoic drugs and antiarrhythmic are of particular importance.
  7. Syndromic patients with visual and hearing impairment may add challenge to the situation.
  8. Scoliosis and muscle contracture may make positioning difficult. Cervical flexion abnormalities and obesity also contribute to the problem.
  9. Conduct of anaesthesia must be done in a very controlled planned manner. Small doses of sedation like midazolam or fentanyl are not sufficient for these patients and can sometimes make situations worse leading to hypoxia. A full theatre set up is essential for even minor procedures. Induction in any form, inhalational or intravenous will be difficult and requires help from theatre personnel. Issues in immediate postoperative period that may be of concern include delayed recovery, emergence phenomenon and behavioral problems.

References

  1. Jules E Allt, et al. Down’s syndrome. British J Anaesth CEPD Rev. 2003;3(3).
  2. Chen H. Down syndrome: eMedicine Pediatrics: Genetics and Metabolic Disease http://emedicine.medscape.com/article/943216-overview
  3. Roizen MF. Anesthetic Implications of Concurrent Diseases. p974 In: Anesthesia Ed: Miller RD. Churchill Livingstone 2000. 5th edition
  4. Mik G, et al. Down syndrome: orthopaedic issues. Curr Opin Ped 2008:20;30-36.
  5. Tod B Sloan. Anaesthesia for dental surgery in mentally handicapped adult. Pg 570-571 Decision Making in Anesthesiology: An Algorithmic Approach Lois L. Bready, Dawn Dillman, Susan 4th Edition 2007.

Not everyone is given a chance to serve humanity as a doctor and especially as an anesthesiologist.

Feel privileged and blessed to be one.

PERI-OPERATIVE

Chapter 02

CO2 Embolism in Laparoscopic Surgery

A 55-year-old woman, moderately obese, weighing about 85 kg – BMI of 35, was posted for emergency laparoscopic cholecystectomy. She had complaints of abdominal pain and fever with vomiting for the last 5 days, diagnosed as acute pyogenous cholecystitis. She had no other known comorbidities. All investigations were normal except a raised WBC count.

The plan was to take her up under general anaesthesia with controlled ventilation.

Drugs used were Propofol 150 mg, Fentanyl 100 mcg, Vecuronium 6 mg. Following intubation with cuffed 7.0 size endo tracheal tube, anaesthesia was maintained with Sevoflurane, Oxygen and Nitrous Oxide. Standard monitors were applied. Her pulse rate was 102/min and blood pressure of 130/70, oxygen saturation 100%, and etco2 was 38. She was positioned supine with a head up tilt for ease of visualization and the surgery commenced.

Surgeon introduced the trocar at the epigastrium for the first port. After confirming intraperitoneal placement, carbon dioxide insufflation was started. Immediately after that, a sudden drastic fall in BP to 70/40 mm Hg and tachycardia of 130/min was noticed.

The end tidal carbon dioxide reduced from 38 to 8 mm Hg. Chest auscultation revealed absent breath sounds on the right side. Immediate diagnosis was pulmonary embolism caused by carbon dioxide insufflated into the system.

Surgery was temporarily discontinued and 100% oxygen administered. Intravenous fluids was given rapidly, and Dopamine infusion 8 mcg/ kg was started. PEEP was instituted and ventilation continued. The Etco2 which had dropped, gradually returned to 25. Heart rate came down to 86/min and blood pressure returned to 100/60 within about five minutes.

As the patient was quickly stabilized, chest was clear with good oxygenation, and the indication for surgery being septic gall bladder, the team decided to proceed with cholecystectomy despite the event. After the 4 ports were in place, a rent on left lobe of the liver was identified and cauterized. Surgery lasted for about one and a half hours with no further untoward incidents. She was extubated on the table, and advised post-operative oxygenation with mask at 3L/min.

She was transferred to intensive care unit for observation. She did well for the first 48 hours. However, on day 3, she complained of mild cough. Chest auscultation revealed scattered rales and rhonchi on the right base. Vitals remained stable with oxygen saturations 97%, pulse rate=90/min, and blood pressure of 100/70. She was mobilized, fed and reassured. On day 5, her cough worsened. Oxygen saturations dropped to 92% and heart rate had increased to 110/minute. She also complained of occasional haemoptysis.

A chest x-ray revealed collapse of the right basal lung. ECG and ECHO revealed a right sided strain pattern. She was eventually diagnosed as pulmonary embolism, was given appropriate treatment with anti-coagulants and supportive therapy. She recovered well without any sequelae.

Discussion

Carbon dioxide embolism is a rare but potentially serious complication of laparoscopic procedures. It is caused by entrapment of carbon dioxide in an injured vein, artery or solid organ, and results in blockage of the right ventricle or pulmonary artery. Air embolism during laparoscopic surgery, at the point of first port placement and insufflation is a well-recognized and dreaded complication, even in the best of hands. With the use of appropriate monitors and diligent observation of the patient, early detection and corrective treatment can be done rapidly.

On this occasion, the complication was immediately recognized due to sudden change of vital signs and patient was resuscitated successfully. Patient was hemodynamically stable and ventilation parameters were acceptable after that. The concern at this point was whether surgery should have been continued. We had to proceed with surgery due to the nature of illness. Secondly, it could have been converted to open surgery to avoid effects of pneumoperitoneum. But there are arguments in favour of both techniques. On one hand, we have deleterious effects of pneumoperitoneum on an affected lung, and on the other hand the potential postoperative complications of open surgery in a septic patient.

Questions at the end of the surgery after successful intraoperative management were;

  1. Should we have deferred extubation and opted for elective postoperative ventilation?
  2. Could we have started non-invasive ventilation on day 3 immediately after symptoms started postoperatively?

The delayed symptoms seem to describe a residual effect of the air embolism with superadded sepsis. It could have been a pulmonary infarct or gradually increasing non-cardiogenic pulmonary oedema. Surely a more aggressive approach on day 3 in the form of anti-coagulants, and ventilation would have assisted in enhancing recovery.

Pathophysiology

  1. Rapid entry of air into the circulation may cause severe haemodynamic instability
  2. Migration of gas emboli into pulmonary circulation increases the pulmonary artery pressure which in turn increases resistance to right ventricular outflow
  3. Decreased pulmonary venous return, decreased left ventricular preload, decreased cardiac output lead to cardiovascular collapse
  4. There is ventilation perfusion mismatch, intrapulmonary right to left shunt, increased alveolar dead space giving rise to arterial hypoxemia, and arrhythmias. Myocardial ischemia may also occur.
  5. Embolism of up to 50 ml may not have any sequelae; 50-300ml will show variable response spectrum from hypotension to total collapse and death.

Clinical diagnosis and vigilant care under anaesthesia is essential. Monitors like precordial and transoesophageal Doppler ultrasonography and trans oesophageal echocardiography are most sensitive to detect gas emboli and add value to the management of the patient.

Treatment of CO2 embolism includes the discontinuation of Nitrous Oxide. Although Nitrous Oxide does not enlarge the CO2 embolism as it does with an air embolism, it is essential to provide the patient with 100% oxygen. Insufflation should be stopped and an increase in the rate and tidal volume of controlled ventilation with positive end-expiratory pressure should be initiated to minimize the gas entrainment. If possible, the patient should be placed in left lateral decubitus and steep Trendelenburg positions. This allows the gas to become trapped in the apex of the right ventricle rather than the pulmonary outflow tract.

Other causes of air embolism include entry of air through intravascular catheters such as peripheral and central venous cannula, pulmonary artery catheters, haemodialysis catheters, pressurised infusion systems, and long term central catheters such as Hickman catheters.

References

  1. S. Sviri, et al. Critical Care and Resuscitation 2004;6:271-276.
  2. Yao F-SF, Malhotra V, Fontes ML, eds. Yao and Artusio’s Anesthesiology Problem- Oriented Patient Management. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2008:875-877
  3. Longnecker DE, Brown DL, Newman MF, Zapol WM, eds. Anesthesiology. 1st Ed. New York, NY: McGraw-Hill; 2008:1496
  4. Hong JY, Kim WO, Kil HK. Detection of subclinical carbon dioxide embolism by transesophageal echocardiography during laparoscopic radical prostatectomy. Urology. 2010; 75(3):581-584.
  5. TN Wenham Venous gas embolism: an unusual complication of laparoscopic cholecystectomy. Journal of minimal access surgery 2009Apr-Jun; 5(2):35-36

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