Volume 3 - Issue 4
Anaesthesia for lower limb surgery in a paraplegic
Dr. Vasanthi Vidyasagaran*
Department of Anaesthesiology, Kauvery Hospital, Chennai, Tamilnadu, India
A 39-year-old man was admitted for a fracture neck of femur, posted for a hemiarthroplasty. During the preoperative visit, history revealed that patient was paraplegic for the past 3 years following a road traffic accident. The current situation was due to a fall from his wheelchair and there was difficulty in nursing. He had an old complete spinal cord injury at level of T6/T7.
Also, due to the paraplegia, the diagnosis was delayed as the patient did not have any pain.
On clinical examination, he was a well-built anxious man, weighing about 80 kg. Pulse rate was 100/min and BP was 130/80. His cardiovascular and respiratory system were normal. Investigations showed Hb=12 gm, renal function tests were within normal limits, Serum K = 4.8 meq/L. ECG and chest x-ray were normal. He had been well cared for otherwise, no recent ICU admissions or any bladder/bowel problems.
We were in a clinical dilemma at this point. We had to consider the pros and cons of administering any form of anaesthesia to this patient. Questions that ran through our minds:
It was decided to go ahead with the procedure under IV sedation, with local anaesthesia, since he did not have any pain due to the fracture. Oxygen was administered via face mask and IV Midazolam 2 mg was given.
Once the incision was made, patient developed tachycardia, pulse rate raising up to 140/min. He began to sweat profusely but did not complain of pain. We asked him if he was uncomfortable, but he denied. Additional 1 mg Midazolam was administered but it did not help in reducing the heart rate. His blood pressure was 190/120 mm Hg. ECG monitoring revealed sinus tachycardia. Preservative free Lignocaine 80 mg IV was administered, the action of which lasted only 10 minutes. The heart rate which came down to 110, soon went up to 140/min.
Assuming this was due to the surgical stimulus, a decision was made to commence general anaesthesia as autonomic dysreflexia was suspected. GA was started with Propofol 150 mg, Morphine 4 mg IV, the patient was intubated with Vecuronium 6 mg, and maintained with Oxygen/Nitrous Oxide and 1% Isoflurane. The heart rate stabilized at 100/min. BP maintained around 130/90 mm Hg. The surgery was completed and the recovery was uneventful.
Postoperative blood pressure was 130/80 and the heart rate continued to be at 100/minute. There was no significant blood loss and 1 litre of Normal Saline was administered intraoperatively. The patient did not complain of pain even in the post-operative period. He did not require any other anti-hypertensives.
Autonomic dysreflexia is a potentially dangerous clinical syndrome that develops in individuals with a neurologic level of spinal cord injury at or above the sixth thoracic vertebral level (T6). It causes an imbalanced reflex sympathetic discharge, leading to potentially life-threatening hypertension. The most common origins are bladder and bowel. It can also be any noxious sensory input.
This strong sensory input travels up the spinal cord and evokes a massive reflex sympathetic surge from the thoracolumbar sympathetic nerves, causing widespread vasoconstriction, most significantly in the sub diaphragmatic (or splanchnic) vasculature. Thus, peripheral arterial hypertension occurs. The brain detects this hypertensive crisis through intact baroreceptors in the neck. The brain attempts to halt the progression of this hypertensive crisis. It cuts down the sympathetic surge by sending descending inhibitory impulses but these impulses are unable to travel to most sympathetic outflow levels because of the spinal cord injury at T6 or above.
Inhibitory impulses are blocked in the injured spinal cord. It also attempts to bring down peripheral blood pressure by slowing the heart rate through an intact vagus (parasympathetic) nerve; however, this compensatory bradycardia is inadequate and hypertension continues. In our patient, we observed the expected hypertensive response to the noxious stimulus (surgical incision). But there was no reflex bradycardia.
This may be due to inadequate vagal compensation with superadded anxiety of the patient.
Assessment of patients with spinal injury must be thorough to avoid catastrophes. The assessment should include level of injury, whether complete or incomplete, sensory level at surgical site, and time since injury â€“ in spinal shock or reflex phase.
No two human beings are alike (even twins) Response to an injury/insult or treatment varies among individuals. This is very relevant to anaesthesia.
A 35-year-old woman with history of cough, difficulty in breathing which exacerbated on lying down and turning to one side, and occasional haemoptysis, presented to interventional pulmonology. Investigations with CT showed large single pedunculated mass occupying 70% of tracheal lumen. Flexible bronchoscopy confirmed the diagnosis. She was booked for rigid bronchoscopy, biopsy and debulking of tumour to allow for better respiratory functioning.
The anaesthetic concerns during this procedure included:
The plan of care was to start with total intravenous anaesthesia (TIVA), induce the patient and maintain spontaneous respiration, introduce rigid bronchoscopy and get it beyond lesion and then paralyse and ventilate through the side port of the rigid bronchoscope.
With patient in semi-reclined position (comfortable for spontaneous respiration), she was preoxygenated with 100% oxygen and IV line was secured. Nebulised bronchodilator was given following a dose of IV Glycopyrrolate and IV Midazolam 1mg.
Emergency drugs and airway equipment were kept ready. Sedation using IV Propofol and IV Dexmedetomidine were commenced based on the patient's weight. As the patient was deeply anaesthetized and spontaneously breathing, glottis was sprayed with 10% Lignocaine, and then rigid bronchoscope introduced by the pulmonologists. Bolus of IV Fentanyl 50 mcg was given at this point to attenuate intubation response. Respiratory circuit was connected to side port of rigid bronchoscope.
It was not possible to ventilate through this port initially. Pulmonologist visualized the tumour, a pedunculated mass hanging into tracheal lumen, and then slowly navigated the scope through narrow lumen. He successfully passed the scope into bronchus, and then ventilation was feasible. Obtaining an end tidal capnography trace was impossible due to the leak in the system, however clinical assessment of bilateral chest movement and auscultation were used to assess ventilation.
Oxygen saturations were maintained around 95% on 100% oxygen and the patient remained hemodynamically stable. TIVA was used to maintain anaesthesia. Atracurium was given once airway was secured with rigid bronchoscopy and clear lumen of carina visualised. Single dose of IV Dexamethasone 8 mg was given. Lesion was vascular and bleeding commenced as the pulmonologist started manipulating it.
Cryo-ablation and Argon Plasma Coagulation helped debulk the tumour and improve tracheal lumen size, at the same time ensuring haemostasis. During all this time, 100% oxygen was administered intermittently, and saturations were maintained around 92-94%,while constantly communicating with the surgeon, and watching the procedure and intense monitoring of the patient.
At the end of the procedure, rigid bronchoscope was taken out after haemostasis and the patient's airway was maintained with facemask. Laryngeal mask airway or an endotracheal tube may also be used during this interim period while waiting for the patient to start breathing and maintain own airway. Nebulised bronchodilator may be administered if needed. In this case, the patient recovered from the relaxant effect promptly and once regular breathing pattern was ensured and patient was awake and responsive, she was shifted to recovery and then to the ward where her vitals were monitored on a regular basis.
Anticipation of problems and adequate planning with effective execution and communication is the key to successful management of airway challenges, and all supporting staff must be familiar with the procedure. This basic rule cannot be emphasized more.
Ventilation in a patient for rigid bronchoscopy can be highly challenging. Usually these patients have poor respiratory reserve. Various methods like apnoeic ventilation, spontaneous assisted ventilation, controlled ventilation, high frequency jet ventilation are employed to ensure oxygenation and ventilation.
Extubation is as important as intubation, and one must ensure complete reversal of any neuromuscular agent used. Short acting sedation agents and narcotics must be wisely used. High risk consent form must be obtained with all risks including death on table explained to the patients and relatives beforehand, as there are high chances of having loss of airway, due to tumour block or bleed, and tracheostomy may not be of use if tumour was completely obstructing the airway.
The following serious complications can happen and they must be prevented by the involved clinicians and they must be adequately trained to deal with them if they do occur.
One should be ready for cardiopulmonary bypass if a need were to arise.
If you fail never give up. Because FAIL means First Attempt In Learning.
- Abdul Kalam