Cardiac disease can be encountered during pregnancy with the frequency being 1% to 2% of all pregnant women. Because of the high foetal and relative maternal mortality during surgery, medical management is the first line of treatment. Nevertheless, when medical treatment fails, cardiac surgery becomes necessary. We present the anaesthetic management of a case of Aortic valve disease in a pregnant woman undergoing surgery

Khan, Fazal Hameed

Siddiqui, Khalid M

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eCommons@AKUDepartment of Anaesthesia Medical College, PakistanSeptember 2008Anaesthetic management of a pregnant patient foraortic valve replacementKhalid M SiddiquiAga Khan UniversityFazal H KhanAga Khan UniversityFollow this and additional works at: http://ecommons.aku.edu/pakistan_fhs_mc_anaesthPart of the Anesthesiology Commons, and the Surgery CommonsRecommended CitationSiddiqui, K., Khan, F. (2008). Anaesthetic management of a pregnant patient for aortic valve replacement. Journal of the PakistanMedical Association, 58(9), 521-2.Available at: http://ecommons.aku.edu/pakistan_fhs_mc_anaesth/34Vol. 58, No. 9, September 2008 521Case ReportAnaesthetic management of a pregnant patient for Aortic valve replacementKhalid M. Siddiqui, Fazal H. KhanDepartment of Anaesthesia, Aga Khan University Hospital, Karachi.AbstractCardiac disease can be encountered duringpregnancy with the frequency being 1% to 2% of allpregnant women. Because of the high foetal and relativematernal mortality during surgery, medical management isthe first line of treatment. Nevertheless, when medicaltreatment fails, cardiac surgery becomes necessary. Wepresent the anaesthetic management of a case of Aorticvalve disease in a pregnant woman undergoing surgery. Case ReportA 25-year-old woman gravida III para II had historyof breathlessness since 3-4years. She noticed shortness ofbreath and dyspnea on exertion at 20 weeks gestation. Shealso complained of dizziness and fainting one month back.On her antenatal checkup she was found to have a grade 3systolic murmur. Echocardiography showed calcified aorticvalve with ventricular movement, and mild symptomatichypertrophied normal sized left ventricle. She was referredto the cardiothoracic surgeon who decided for aortic valvereplacement. Grade III dyspnea was found on pre operativeevaluation. Obstetrical examination revealed positive foetalviability. Poor foetal outcome was feared due to non pulstileflow during cardio pulmonary bypass. Patient was preparedfor the surgery. Aspiration prophylaxis along withantibiotics were given prior to the procedure. During the surgery, routine monitors were applied,and a 14G cannula inserted in the right hand under localanaesthesia. Invasive arterial line using Seldinger'stechnique was also placed. Rapid sequence induction wasdone with injection fentanyl 7µg/kg body weight, thiopentalsodium 3mg/kg body weight and rocuronium 0.9mg/kgbody weight. Air way was secured by size 7.5mmendotracheal tube (ETT) which was confirmed by end tidalcarbon dioxide and chest auscultation. Swan ganz catheterfrom right internal jugular vein for haemodynamics andfluid management was placed after induction along withextra 14G cannula in right hand.Aortic valve replacement was done using cardiopulmonary bypass with non pulstile blood flow usingmembrane oxygenator and blood cardioplegia. The patientwas cooled to 30° centigrade during the procedure.Anaesthesia was maintained with propofol infusion at therate of 2mg/kg/hr. Mean arterial pressure was maintainedbetween 50-60 mmHg during cardio pulmonary bypass witha pump flow of 2.5 liters/min. After completion of surgerypatient was weaned off the cardio-pulmonary bypass.Patient remained haemodynamically stable. After surgerythe obstetrician performed the foetal examination forviability, there was obvious heart sound which wasconfirmed by cardio tocho graph (CTG). The patient wasshifted to cardiac intensive care unit. Extubation was doneon the next day of surgery. Patient was shifted to the wardand discharged, on the 5th postoperative day.At 37th week of pregnancy she was admitted againfor elective Caesarean section, under general anaesthesia. Ahealthy baby boy weighing 2.9 kg with Apgar score of 8 and9 was delivered.DiscussionThe incidence of maternal heart disease duringpregnancy has been estimated to be 1.5%1. Most of thepregnant women with heart ailments seen at referral centersare those with congenital heart disease. The next largestgroup includes women with rheumatic heart disease2. Aorticstenosis is infrequently encountered during pregnancy andis usually due to a congenitally abnormal valve. Patientswith mild aortic stenosis usually tolerate pregnancy well.Patients with moderate or severe aortic stenosis are verysensitive to preload changes and hypotension. They areunable to augment cardiac output (Co), with increase in LVsystolic and filling pressures leading to heart failure andischemia. Cardiac surgery during pregnancy has played alimited but defined role alongside the accepted medicalmanagement in the overall care of the patient. Maternalmortality associated with cardiac surgery varies from 1.5%to 4.2%, compared with the foetal mortality rate of 9.5% to33%4.There are now many reports of foetal survival toterm after corrective surgery performed in the second orthird trimesters4. The main goal in the management of thesepatients is to prevent further derangement of cardiacfunction during surgery and labour in a heart which isalready stressed by the "physiological" changes ofpregnancy. This can be accomplished by effectiveanxiolysis, analgesia and anaesthesia. Ultimately, the aim ofany anaesthetic intervention is to ensure the well being ofboth the mother and the foetus. When cardiac surgery isperformed during pregnancy, foetal mortality is 20-35%. Itis the additional cardiac burden associated with pregnancythat often causes heart disease to show itself at this time.When surgery is needed, timing is of key importance for thewelfare of the foetus. During the first trimester, any injuryto the foetus, whether due to drugs, hypoxia or changes inblood flow, has a high probability of causing congenitaldefects and spontaneous abortion. The third trimester is atime of low risk for the foetus, especially beyond 28 weeks,because if labour is precipitated by surgery, there is a goodchance that the baby will survive in a neonatal unit, and thefoetus is more resilient during cardiopulmonary bypass atthis stage. However, by the third trimester, a gravid womanrequiring surgery for a cardiac defect, will have a higher riskbecause of the extra cardiac output. In the second trimesterthe risk is similar to a non-pregnant woman, along with alower risk for premature labour5.There is always a concern on the effects ofanaesthetic agents on foetal development and teratogenicity,especially during the first trimester. It has been evidencedthat most anaesthetic agents, intravenous, inhalatory, andparalyzing agents are devoid of teratogenic effects and canbe safely employed in a pregnant patient6. Drugs that areknown to be safe, or do not cross the placenta, should beused. Vasoconstrictors are avoided due to the effect on theuterine spiral arteries. Hypocarbia as a result of mechanicalhyperventilation decreases the uterine blood flow by 25%,although the blood pressure remains unchanged duringhyperventilation. The adverse effect on uterine blood flow isattributed to a decrease in venous return and cardiacoutput7,8.The dangers of CPB include changes in coagulation,alteration in the function of cellular and protein componentsof the blood, release of vasoactive substances fromleukocytes complement activation, particulate and airembolism, non pulsatile flow, hypothermia andhypotension.7 All these factors can compromise the delicatebiological equilibrium between the foetus and the placenta.There are only few studies regarding the effects of maternalCPB on the foetus. Since the first report of the use of foetalheart recording during bypass by Koh and Co-workers9 in1975, it has been known that foetal bradycardia occursalmost invariably at the onset of maternal CPB. Whatcauses bradycardia at the beginning of the bypass isunknown, but it may be related to decreased foetaloxygenation secondary to placental hypotension or to acidbase changes. The changes in foetoplacental perfusion duringcardiopulmonary bypass are poorly understood, despite newmethods for monitoring flow in the uterine artery, ductusvenosus and foetal aorta. It is known that hypothermia cancause foetal hypoxia and that rewarming can likewise causehypoxia by inducing uterine contractions. There are only afew reports of surgery with circulatory arrest and deephypothermia, and in all of these the foetus diedpostoperatively. During cardiopulmonary bypass,haemodilution, lack of pulsatile flow, uterine arterial spasmand particulate microemboli may all alter placentalperfusion and contribute to foetal hypoxia. With pulsatileperfusion during cardiopulmonary bypass, the hazard ofvasoconstriction in placental vessels, including spiralarteries, is believed to be lessened by release of nitric oxide.Thus; in pregnancy cardiopulmonary bypass is bestconducted with mild hypothermia, pulsatile perfusion, highflow rates and minimal haemodilution.10,11ConclusionCardiac surgery during pregnancy can be performedsafely by using cardiopulmonary bypass. Maternal risks arerelated to the specific procedure performed. A high risk offoetal morbidity and mortality is associated with CPBduring pregnancy. Foetal bradycardia and increased uterinecontractions need immediate attention and management.With the optimal care provided by the modern neonatal careunits and considering caesarian section as an option, thedeleterious effects of CPB can be avoided when thegestational age is above 28 weeks.References1. Szekely P, Snaith L. Heart disease and pregnancy. Edinburgh: ChurchillLivingstone 1974. pp 137.2. Siu SC, Colman JM. Heart disease and pregnancy. Heart 2001. 85:710-15.3. Abbas AE, Lester SJ, Connolly H. Pregnancy and the cardiovascular system;Int J Cardiol 2005; 98:179-89.4. Bernal JM, Miralles PJ. Cardiac surgery with cardiopulmonary bypass duringpregnancy. Obstet Gynecol Surg 1986. 41:1-6.5. Agarwal RC, Bhattacharya PK, Bhattacharya L, Jain RK. Pregnancy andcardiopulmonary bypass.  Indian J. Anaesth; 2004. 48:259-636. Duncan PG, Pope WD, Cohen MM, Greer N. Fetal risk of anaesthesia andsurgery during pregnancy. Anesthesiology 1986; 64: 790-94.7. Hammon JW Jr, Edmunds LH Jr. Extracorporeal circulation: Organ damage.Cohon LH, Edmunds LH Jr. Editors Cardiac surgery in the adult. McGraw-Hill, New York 2003; pp 361-388.8. Levinson G, Shnider SM, DeLorimier AA, Steffenson JL. Effects of maternalhyperventilation on uterine blood flow and fetal oxygenation and acid basestatus. Anesthesiology 1974; 40: 340-47.9. Koh KS, Friesen RM, Livingstone RA, Peddle LJ. Fetal monitoringduring maternal cardiac surgery with cardiopulmonary bypass. Can MedAssoc J 1975; 112: 1102-04.10. Parry AJ, Westaby S. Cardiopulmonary bypass during pregnancy. Ann ThoracSurg 1996; 61: 1865-59. 11. Kahler R. In : Medical complications during pregnancy, in: Burrow G andFerris T, Eds. Cardiac Diseases Philadelphia Saunders, 1975; pp 105.522 J Pak Med Assoc

Anaesthetic management of a pregnant patient for aortic valve replacement

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Anaesthetic management of a pregnant patient for aortic valve replacement

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