Critical issues in a parturient with pre-existing neurological deficits with severe anaemia: A clinical challenge to anaesthesiologist and intensivist!

Sir,

The ignorance towards general well being of an individual and his/her nutritional aspects, poverty and a low level of literacy, probably contribute to a higher prevalence of nutritional disorders such as anaemia, upto an incidence of 65-70%, in Indian population.[12] The pathological features of anaemia gets further potentiated during pregnancy, and when these patients come for emergency surgeries, the attending anaesthesiologist has to face great difficulties and challenges in managing such cases smoothly. We report a 24 year old third gravida female at 36 weeks of gestation, from low socio economic strata presenting with leaking per vaginum, and difficulty in breathing with an uneventful present obstetric history. She had suffered from paralytic poliomyelitis in childhood with residual paralysis in bilateral lower limbs, with no history of breathing difficulties or recurrent respiratory tract infections.

A quick but thorough pre-anaesthetic evaluation showed signs of congestive cardiac failure due to severe anaemia, and decision for immediate caesarean section was taken, and general anaesthesia was planned. A rapid sequence induction with constant cricoid pressure was carried out with intravenous thiopentone sodium 5 mg/kg and neuromuscular blockade was achieved with succinylcholine 2 mg/kg. This was followed by tracheal intubation. Anaesthesia was maintained with nitrous oxide in oxygen in a ratio of 50:50, and titrated concentrations of isoflurane and vecuronium used for neuromuscular blockade. A live healthy male baby was delivered, and twenty international units of oxytocin were given as slow intravenous infusion.

At the end of surgery, residual neuromuscular blockade was reversed; however, the patient had a delayed awakening with shallow respiratory efforts and desaturation upto 70% inspite of administration of 100% oxygen. Exacerbation of underlying cardiac failure was suspected, and subsequently she was shifted to intensive care unit for further management. She was mechanically ventilated with high inspired oxygen concentration. A central venous access was secured and her initial central venous pressure was measured to be 18 mmHg which was significantly higher than the normal range of 8-12 mmHg. After evaluating her clinically and through electrocardiographic and echocardiographic findings (dilated cardiomyopathy with left ventricular ejection fraction of 30.8% but no regional wall motion abnormalities), injection Frusemide 20mg IV three times daily and Injection Digoxin 0.25 mg single daily dose was advised. She remained hemodynamically stable; however, had repeated episodes of congestive cardiac failure, hence, her mechanical ventilation was continued. Her arterial blood gas analysis showed hypoxia with chest radiograph showing increased cardiac silhouette with evidence of basal congestion. Electrocardiography (ECG) revealed ischemic changes in lateral leads with raised creatine phosphokinase myocardial band (CPK-MB) enzyme titres, which normalised within next 24 hours. Thus, diagnosis of acute myocardial infarction was assumed less likely. Her clinical condition improved over the next 3 days and she was extubated on 5th postoperative day, and was advised treatment with diuretics and angiotensin converting enzyme inhibitors till further follow up.

Our patient had clinically overt severe anaemia according to the World Health Organization classification of anaemia in pregnancy(1989).[3] The physiological anaemia of pregnancy makes pregnant woman more susceptible to contract pathological anaemia.[4] The anaemia further increases load on heart to maintain tissue oxygenation with subsequent increased chances of acute cardiac failure, if cardiac output increases beyond 10 l/minute.[5] Anaesthetic implications in this case were avoidance of factors that interfere with oxygen delivery to tissues, to increase oxygen consumption and optimisation of partial pressure of oxygen in the arterial blood.[5] This patient also had post polio residual paralysis; however, did not fulfil all the criteria's for diagnosis of ‘Post Polio Syndrome’[67] i.e., syndrome of acute exacerbation of motor paralysis in a patient with past history of poliomyelitis. The main anaesthetic concerns in these patients involve positioning issues due to contractures and spinal deformities, increased sensitivity to the sedative effects of opioids, postoperative respiratory complications due to decreased functional residual capacity, increased chances of regurgitation and a possible aspiration and increased sensitivity to non-depolarising muscle relaxants. The other significant aspect includes the hesitancy to use regional anaesthesia because of pre-existing neuromuscular deficits and medico-legal issues in post polio patients.[8] There is no literary evidence of any adverse events associated with regional anaesthesia in these patients; however, there have been concerns that minimum toxic intrathecal concentration of local anaesthetics may be lower in these patients as compared to normal population.[9] The general anaesthetic technique used in these patients should involve use of titrating doses of all anaesthetic drugs to their desired effects.[10] Postoperatively, these patients require vigilant monitoring in lieu of increased sensitivity to opioids and possibility of respiratory failure. There has been controversy regarding the use of succinylcholine in patients with neuromuscular diseases for the danger of precipitating hyperkalemia; however, there is no specific data on its use in this subset of population.[10]

Another important finding in this patient was dilated cardiomyopathy, which could have been caused by pregnancy itself, an entity known as Peripartum Cardiomyopathy, as was evidenced by the repeated cardiac failure in the postoperative period. Association of acute polio virus infection with myocarditis subsequently causing dilated cardiomyopathy has been documented in literature; however, its association with increased incidence of peripartum cardiomyopathy is unknown.[1112] In conclusion, our patient posed three important anaesthetic challenges i.e. severe anaemia, post polio residual paralysis and dilated cardiomyopathy, so a general anaesthetic technique was chosen keeping in consideration the various implications.