PERI-OPERATIVE

Chapter 07

Hypothermia in an Elderly Patient

Dr. Vasanthi Vidyasagaran*

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

*Correspondence: [email protected]

An 80-year-old man weighing 50 kg, who was diagnosed with carcinoma of stomach, was posted for radical gastrectomy. The anaesthetic plan was combined epidural and GA.

The epidural catheter tip was placed at T9. GA was then induced with Propofol 100 mg, Fentanyl 100 mg, and patient was intubated using Atracurium 30 mg. Anaesthesia was maintained with Oxygen/Nitrous Oxide and Isoflurane 1%. Patient’s intraoperative vitals were monitored throughout. Pulse rate was between 76-85 beats/min, BP was between 100/60-110/70, SaO2 97-98%, urine output around 40 mL/hour.

The surgery lasted four hours, during which a total relaxant dose of 75 mg was used. During closure of the abdomen, an epidural of 6 ml 0.25 % Bupivacaine was initiated for postoperative pain relief. At the end of the procedure, patient did not seem to recover as anticipated. There were no spontaneous breathing attempts even after 45 min of completing the surgery.

A senior anaesthesiologist was called for help. On examination, the peripheries of the patient were cold, pupils constricted, urine output was 200 mL, and all other parameters were normal. The anaesthetist recommended a temperature check using the nasopharyngeal probe which showed low temperature of 32°C!

On gradual rewarming with warm blankets and warm IV fluids, the patient recovered smoothly and slowly started breathing spontaneously. He was then reversed and extubated successfully after about 1 h. It was a case of inadvertent hypothermia in a geriatric patient.

Discussion

There is significant evidence that hypothermia affects morbidity and mortality of surgical patients, with detrimental consequences in patients of all ages. In this case, the air conditioner vent was directed straight at the patient. This does not comply with the standards of OT construction. There should be no air currents and the ambient temperature inside the OT should be the same without any cold pockets. This unfortunately, is still not practiced in most theatres in Chennai which continue to have window and split unit air conditioners.

Temperature monitoring is included in the minimum mandatory monitoring and should be followed at least in paediatric and geriatric patients which again is not done as a routine in practice. Patients can drop 1-2 degrees core temperature even between arrival into operating theatre and start of surgery. It is recommended that at-risk patients (very sick patients, septic shock, extremes of age), or those undergoing long surgeries are identified and warming measures activated prior to induction of anaesthesia.

Patients recovery time is significantly prolonged by hypothermia, and they also experience shivering.

Shivering increases Oxygen consumption. Redistribution of core heat during general anaesthesia exacerbates heat loss.

Neuraxial anaesthesia also affects thermoregulation by decreasing shivering and vasoconstriction threshold

Peri-operative hypothermia is a common preventable complication of anaesthesia. It is important to measure temperature in all surgical patients under anaesthesia.

Hypothermia usually occurs during prolonged procedures under general anaesthesia but it is not uncommon even during regional anaesthesia. It is worthwhile measuring temperature, and maintain normothermia, in all patients whatever be the technique of anaesthesia. Any rewarming in patients with hypothermia must be done gradually.

Induced hypothermia during cardiac surgery is not the same as unintentional hypothermia during other surgical procedures. In this situation, hypothermia contributes towards improving patient outcome by maximising cerebral protection.

References

  1. J. Andrzejowski, et al. Effect of prewarming on post- induction core temperature and the incidence of inadvertent perioperative hypothermia in patients undergoing general anaesthesia. Br J. Anaesth. 2008;101(5):627-631.
  2. NICE, The management of inadvertent peri-operative hypothermia in adults. National Collaborating Centre for Nursing and Supportive Care commissioned by National Institute for Health and Clinical Excellence (NICE): April 2008. Available from http://www.nice.org.uk/nicemedia/pdf/CG65Guidance.pdf

PERI-OPERATIVE

Chapter 08

Lumbosacral Neuropathy Due to Positioning

A 60-year-old man was posted for a dynamic hip screw fixation for an inter-trochanteric fracture of his right femur. He was a known diabetic with controlled sugar levels. His preoperative examination and investigations were all within normal limits.

The case was started under spinal anaesthesia, given with a 26G Quincke needle and 3 ml 0.5% Bupivacaine and 25 micrograms of Fentanyl. It was an uneventful spinal anaesthesia.

Patient was haemodynamically stable and the surgery proceeded smoothly. At the time of reducing the fracture, fixing the plate and screw, the C-arm was called for. The inexperience of the surgeon and the theatre assistant resulted in abducting and extending the patients leg, to suit the C-arm, rather than moving the C-arm to suit the position of the leg. While the left leg which was tied on the stirrup, was also stretched beyond limit. On noticing this abnormal positioning of legs, an experienced technician was summoned by the anaesthetist to help reposition the limb and view the fixation of the fracture. The surgery was completed uneventfully. The immediate postoperative period was uneventful.

On the first postoperative day, the patient complained of heavy leg with altered sensation on non- operated lower limb. On examination he had mild weakness, power 4/5, and reflexes were normal. Paraesthesia was elicited along L4/L5/S1 distribution. Lumbosacral radiculopathy was suspected.

MRI of lumbosacral spine revealed no abnormality, suggesting no sequelae from spinal anaesthesia. EMG and nerve conduction studies revealed peripheral neuropathy along sciatic nerve distribution. Diagnosis was peripheral nerve injury as post-operative complication. Neurologist suggested commencing steroids and physiotherapy. Patient gradually improved and by three weeks attained normal neurological function.

Discussion

This was a case of lumbosacral neuropathy as a complication following undue traction on lumbosacral trunk. Over abduction and external rotation of the limb accidentally done by the technical team in a paralysed lower limb can cause nerve injury, mostly reversible, however some may remain permanent. While focusing on the fracture site, attention must also be given to the non-operated limb. The condition could also have been precipitated due his diabetic status.

‘Do no harm’

Extreme care must be taken while positioning patients on a fracture table. Perineal support, lower limb foot support, and appropriate traction and optimal abduction to avoid injury to the nerves.

The incidence of permanent nerve damage after a surgical procedure and anaesthesia is 0.03% to 1.4%. These have serious medicolegal implications and we are duty-bound as a team to ensure safety and maintain records. Follow-up of patients and appropriate support is essential in these circumstances.

Of all the peripheral nerve injuries, the most common are ulnar nerve (28%), brachial plexus (20%), lumbosacral nerve root (16%), and spinal cord (13%). Thin patients, long procedures, inadequate pressure padding and support, and low perfusion pressure have been implicated as high-risk factors.

Even while operating on the upper limb, especially in the swimming position for a fracture humerus, the normal limb gets compressed due to positioning and patients experience severe discomfort when it is done under the block. This issue must be addressed and the non-operated limb must be well protected. Occasionally, patients experience some neuropraxia even after all the precautions have been taken.

References

  1. Lalkhen AG., Bhatia K. Perioperative peripheral nerve injuries. Contin Educ Anaesth Crit Care Pain 2012;12:38-42.
  2. Nitti J., Nitti G. Anesthetic complications. Clin Anesthesiol. 2006;959-77.
  3. Complications in Regional Anesthesia and Pain Medicine: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2869280
  4. Lumbosacral plexus – an overview | ScienceDirect Topics www.sciencedirect.com/topics/page/Lumbosacral_plexus Problems with lumbosacral plexus can occur due to trauma at the pelvic level … can be due to birth defects/trauma or lumbosacral (carcinomatous) neuropathy. …. nerve trauma resulting from abdominal surgery, lithotomy positioning during …

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