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Case History
A 17 year old Indian Woman, weighing 45 kg., with chronic rheumatic heart disease and sickle cell anaemia, was scheduled for mitral valve replacement. She gave history of progressive exertional dyspnoea, grade II and repeated chest infections over the last 3 years. She gave history of jaundice 2 years ago. However, there was no history of anaesthesia, surgery or blood transfusion in the past. She was pale with a pulse rate of 96 beats per minute and blood pressure of 108/80 mm Hg. Heart sounds were found to be of varying intensity. There was a pan systolic murmur in the mitral area. Chest X-ray showed cardiomegaly and features of severe pulmonary artery hypertension. The ECG showed a heart rate of 100 beats per minute with normal sinus rhythm. P Mitrale was present. ST segment depression and T wave inversion were seen in leads V2 to V6. 2 D Echo confirmed the presence of severe Mitral Stenosis, Mitral Regurgitation with severe Pumonary Artery Hypertension. Mitral valve was thickened with an area of 0.8cm2. There was severe Tricuspid Regurgitation. The Pulmonary Artery Pressures was estimated at 70 mm Hg. Routine blood and urine tests showed anisocytosis, poikilocytosis and polychromasia. Sickling tests for E and L were positive. Her preoperative haemoglobin was 10.3 gm%. S. Biochemistry including coagulation profile was normal.
The patient received tablet diazepam 10 mg per oral 2 hours before surgery. She was well sedated with I V 100 µg Fenatnyl and 1.5 mg Midazolam. Left radial artery and right internal jugular vein cannulation were established under local anaesthesia. Lead II and Lead V of ECG were being continuously monitored. Care was taken to maintain body temperature with both-a warming blanket and a convective warmer to prevent sickling. Antibiotic prophylaxis was given with Inj. Cefatoxime 1 gm I V. SpO2 was being continuously monitored to prevent hypoxia. After preoxygenation for 3 minutes, anaesthesia was induced with I V doses of 100 µg Fenatnyl, 8 mg Vecuronium bromide and 200 mg of Thiopentone Sodium. The trachea was intubated with a 7 no. cuffed portex endotracheal tube. Anaesthesia was maintained with increments of Vecuronium, Fentanyl and Isoflurane in 50% oxygen: nitrous oxide mixture. ETCO2 monitoring was done to achieve normocapnia. Hb, PCV, ABG and S. Electrolytes were tested half hourly to detect any early deviation from normal.1 The mitral valve was replaced using St. Jude’s mechanical prosthesis. The pump flow rate was 2.4 L /Min, Mean arterial pressure was 50 mm Hg, and rectal temperature was never allowed to drop below 35ºC. The haematocrit on bypass was over 25% without priming with blood. Topical hypothermia was also avoided and warm crystalline cardioplegia was used. The total duration of bypass was short at 40 minutes.
There was no macroscopic or microscopic evidence of haemolysis, haematuria or other clinical evidence of sickling. The patient was extubated on table. Hypoxia, hypercarbia, dehydration, hypothermia and acidosis were avoided in the perioperative period. She was ambulated the next day and physiotherapy was given to prevent postoperative chest infections.
Discussion
Sickle cell anaemia is an uncommon haematologic disorder found in the west central Africa, North east corner of Saudi Arabia and East Central India. Presence of HbSS or SC is associated with sickling crisis leading to increased morbidity and mortality. Probable complications associated with sickling are acute chest syndrome, pain episodes, hyper haemolytic crisis, alloimmunisation with delayed transfusion reactions, etc. The complication rates can be higher in patients who need to undergo open heart surgery, wherin haemolysis may result from mechanical trauma, contact with artificial surfaces, increased red cell fragility, hypothermia, acid base disturbances, etc. To minimize sickling during cardio pulmonary bypass, exchange trasnsfusions4 are frequently recommended preoperatively for patients with homozygous sickle cell disease to reduce circulating concentrations of HbS to less than 30%. Perioperative management to avoid sickling5 includes highflow normothermic bypass, avoidance of acidosis, hypoxia, hypercarbia, hypothermia and dehydration. The total cross-clamp2 as well as bypass time should be as short as possible. The patient should be extubated and ambulated early to avoid infections.3
In conclusion, patients with sickle cell anaemia can undergo standard bypass technique if proper precautions are taken.
Referances
1. Marchant WA, Wright S, Porter JB. CABG in a patient with Hb SC disease. Anaesthesia 2001; 56 (7) : 667-9.
2. Merchant WA, Wright S. Aortic Cross-clamping in Sickle cell disease. Anaesthesia 2000; 55 (10) : 1034.
3. Djaiani GN, Cheng DC, Carroll JA, Yudin M, Karski JM. Fast-track cardiac anaesthesia in patients with sickle cell abnormalities. Anesth Analg 2000; 90 (2) : 503.
4. Madan AK, Hartz RS, Major C, McKee P, Flint L. MVR in Sickle cell disease using intraoperative exchange transfusion. J Cardiac Surg 1998; 13 (1) : 48-50.
5. Frimpong-Boateng K, Amoah AG, Barwasser HM, Kallen C. CPB in SCA without exchange transfusion. Eur J Cardiothoracic Surg 1998; 14 (5) : 527-9. |
