Case report:
A one -year- old, 5.5 Kg,with a BSA of 0.33 m2,male child presented withhurried breathing since birth, and recurrentupper respiratorytract infection and easy fatiguability with decreased activity since three months of age.There was no history of cyanotic spells. On auscultation, a pansystolic murmur was present at the left fourth intercostal space. Chest X- ray showed pulmonary artery enlargement, cardiomegaly and increased pulmonary vascularity. Echocardiography revealed a large doubly committed VSD of 8.8 mm with moderate PAH,dilated RA,RV, and pulmonary artery(2.6 cm), and normal biventricular functions with LVEF of 60%, and TAPSE of 21mm.He was puton oraldigitalis, enalapril, sildenafil and furosemide,and after obtaining informed consent from the parents, he was taken up forVSD patchclosure under cardiopulmonary bypass (CPB).He was premedicated with oral midazolam(3mg) two hours before surgery. In OR, standard ASAmonitoring was started. His baseline heart rate was 140 bpm and arterial saturation was 99%. General anaesthesia was induced with fentanyl (50mc), thiopentone sodium (5mg), midazolam( 0.5mg), and vecuronium bromide(1mg) was used to facilitate the endotracheal intubation with 4.5 mm cuff tube.After inductionofanaesthesia, 20GLeadercath was inserted in the left femoral artery for continuous BP monitoring and intermittent ABG analysis. A 4.5 Fr triple lumen catheter was inserted via right internal jugular vein for CVP monitoring and administration of anaesthetic drugs and inodilators.His baseline BP and CVP were 85/ 50mmHgand 6 mmHgrespectively, and ABG revealed a pH 7.40, PO2-176 mmHg,PCO2 -35mmhg, Hb-11gm%, HCO3- 25mmol/l, SaO2- 99.8%. Anaesthesia was maintained with intermittent fentanyl, midazolam, vecuronium bromide, and sevoflurane(1-2%) and oxygen in air with fraction of inspired oxygen (FiO2) of 0.5–1.Anticoagulation with heparin(300U/kg)was used to achieve an ACT of >480 Sec. Aortic cannulation was done using 12 Fr straight Styletted cannula (Medtronic), Venous drainage was done using single stage 14 Fr angled DLP cannula for SVC and 16 Fr angled DLP cannula for IVC. VSD was closed with Gore- Texpatch under standard moderate hypothermic CPB, and potassium enriched (Den-Lido)cardiopegic myocardial protection.Weaning from CPB was easy with the use of infusion of milrinone (0.5mc/kg/min), dobutamine(5 mc/kg/min) and NTG (1mc/kg/min). On direct needle insertion, PA pressures were 22/7(10) mmHg,at cardioplegia line was 70/ 40 mmHgand atside port of the aortic cannula were 35/18mmHg, as compared to femoral artery pressure of 30/17 mmHg. However, on visual assessment, the LV contractility deteriorated and progressed to distension and cardiac arrest andnecessitatedtoreinstitute CPB. Patient had similar repeated three episodes of cardiac arrest on each successful weaning from CPB, and LV contractility and hemodynamicscould not be maintained even with the use of very high doses of inotropes.But we noted an unusual BP difference at proximal to aortic cannulationmeasured by direct needle insertion (90/ 40 mmHg)and femoral artery(30/17mmHg). Therefore, it was decided to insert the TEE probe to rule out coarctation of aorta and other cardiac anomalies, and to assess the VSD patch closure and hemodynamics.TEE confirmedadequate VSD closure, and absence of Coartation of aorta and any other cardiac anomalies, andgood LV contractilitywhile patient was on CPB support.Therefore, one more attempt for weaning off CPB was made under the TEE guidance.However, still there was a big difference between FA pressure and aortic pressure proximal to cannulation. Once again, the LVgot distendedand became almost akinetic. Consequently,the patientalso developed severe mitral regurgitation with 2-3 MR jets and hemodynamic deterioration. [Fig.1, Video 1]Finally in a desperate scenario, it was decided to remove the aortic cannula even in severehemodynamic instability (BP 31/17 mmHg), realizing that the aortic cannula might be the culpritfor thedeterioration of the LV function by obstructing the aortic blood flow.Following aortic decannulation, the LV contractility and hemodynamicsimproved gradually and maintainedevenwith minimum infusion of dobutamine, milrinone. [Fig. 2, Video.2] [Fig.3, video. 3a, 3b]Utmost important to mention here that the similar sudden fall in blood pressure was also noted following aortic cannulation, however, that was managed as usual byvolume administration through aortic cannula andpromptlyinstitution of CPB.Heparin was neutralized with protamine(1:1.3 ratio). Total CPBtimes were188min, 15min,22min, 40 min, and ischemia time was 140 min. Chest was closed after achieving proper haemostasis.His Blood pressureand CVP before shifting to ICU were 90/45 mmHg and 7 mmHgrespectively, and ABG showed a Ph-7.47, HB- 8.8 gm%, PCO2- 27, PaO2-244 mmHg, and SaO2- 99%.Tracheal extubation was done on 2nd postoperative dayandinodilatorstapered slowly. Post -extubation, child was fully alert without any neurocognitive dysfunctions. Rest of the course was uneventful, and patient was discharged on 10th postoperative day.