Abstract

We describe the successful anesthetic management of cesarean section in a patient with Eisenmenger’s syndrome secondary to an atrial septal defect. Although concep-tion  is  discouraged  in  women  with  Eisenmenger’s  syndrome,  in  inevitable  circum-stances, careful and meticulous planning of anesthesia can help the parturient survive the  ordeal  of  a  cesarean  section.  The  cardiac  output  must  be  maintained  and  sys-temic vascular resistance must not be allowed to fall. This should ensure that there is minimal change in the right to left shunt. In our patient, the scenario of Eisenmenger’s syndrome was complicated by biventricular hypertrophy. We achieved the goals in our patient by using general anesthesia with the Proseal® laryngeal mask airway, a com-bination of ketamine and propofol, and epidural analgesia.

Keywords

analgesia, epidural; anesthesia; Eisenmenger complex; laryngeal masks, Proseal®;

1. Introduction

Eisenmenger’s syndrome was originally described in 1897 and the definition was revised by Wood in 1958.¹ It includes pulmonary artery hypertension, reversed or bidirectional shunt associated with an atrial sep-tal defect (ASD), ventricular septal defect and pat-ent ductus arteriosus.²⁻⁴ Death can occur at any time during pregnancy as well in the puerperium.⁵ Here, we  describe  the  anesthetic  management  of  a  preg-nant  woman  at  term  with  Eisenmenger’s  syndrome  secondary to ASD for lower segment cesarean section (LSCS).

2. Case Report

A  24-year-old,  47-kg  pregnant  woman  (gravida  2,  para 1) was admitted to our hospital at 35 weeks of gestation with the major complaint of breathless-ness. On examination, the patient was found to be cyanotic with clubbed fingers and raised jugular ve-nous pressure. Her respiratory rate was 18 breaths/min, blood  pressure  (BP)  was  140/85  mmHg  and  pulse  rate  was  75  beats/min.  On  auscultation,  a  loud S₂ and grade-III/IV systolic murmur was heard over the precordium with right ventricular lift, but the lungs were clear.
Two years previously, during her first pregnancy, ostium secundum type of ASD with severe pulmo-nary hypertension was diagnosed. The patient was advised to have regular follow-ups with the cardi-ologist, but her visits were irregular.

With regard for her health, the patient had ear-lier been advised to undergo medical termination of the second pregnancy by her physicians. Misoprostol was administered orally but the termination was not successful, following which dilatation and curettage was attempted but the procedure was abandoned because   of   the   presence   of   cervical   stenosis.   Therefore,  the  pregnancy  continued.  The  patient  had dyspnea of New York Heart Association (NYHA) grade  1  in  the  first  trimester,  but  it  increased  to  NYHA-III in the third trimester. Two days after ad-mission, she developed premature labor pains and in view of a previous LSCS and cervical stenosis, an LSCS  was  thus  planned.  All  risks  were  explained  and written informed consent was gained.

Preoperative  investigations  including  a  hemo-gram and biochemical tests revealed no abnormal-ities.  Electrocardiography  (ECG)  showed  normal  sinus  rhythm.  Chest  X-ray  revealed  cardiomegaly.  Echocardiography  revealed  biventricular  enlarge-ment,  a  3.2-cm  ostium  secundum  type  ASD  with  right to left shunt, a dilated pulmonary artery with severe  pulmonary  hypertension  (70  mmHg),  mod-erate tricuspid regurgitation and right ventricular systolic   pressure   of   135   mmHg   with   ejection   fraction    of    55%.    Preoperative    atmospheric    arterial  blood  gas  analysis  revealed  pH  7.381,  PCO₂  27.2  mmHg,  PO₂  45.5  mmHg,  base  excess  6.6 mmol/L,  HCO₃ 15.7 mmol/L and SaO₂ 79.4%.

Preoperatively, prophylaxis for infective endocar-ditis and aspiration were administered. The patient was  conveyed  to  the  operating  room  in  a  30º  head-up tilt left lateral position with oxygen sup-plementation by facemask. Standard monitoring in-cluding  pulse  oximetry  (SpO₂),  noninvasive  BP  monitoring, ECG, and capnography were established. An  epidural  catheter  was  inserted  in  the  left  lat-eral  position  via  the  L_3,4  interspace.  Under  ultra-sonographic guidance and local anesthesia the right internal jugular vein was cannulated with a triple lumen central venous catheter and the central ve-nous pressure (CVP) then measured 12 mmHg. A 20G radial artery cannula and two 16G venous cannulas were inserted and secured.

Anesthesia  was  induced  with  ketamine  50  mg,  propofol 70 mg and fentanyl 50 μg, and neuromus-cular  blockade  was  achieved  with  vecuronium  5 mg. Ventilation was assisted and anesthesia was maintained  with  isoflurane  (1%)  in  oxygen  (100%)  conveyed by a size 3 Proseal® laryngeal mask air-way  (PLMA).  Anesthesia  was  maintained  with  iso-flurane (1−1.5%) in O₂ and air (80:20 mixture), and vecuronium.  A  2-kg  baby  was  delivered  with  an  Apgar score of 9 at 1 minute and 10 at 5 minutes. Uterine massage and a slow oxytocin infusion were started.

After the delivery, fentanyl (50 μg) was injected, and  3  mg  morphine  diluted  in  8  mL  of  0.1%  bupi-vacaine was administered epidurally. As the patient remained  hemodynamically  stable  throughout  sur-gery,  neuromuscular  block  was  reversed  with  ne-ostigmine (2.25 mg) and glycopyrrolate (0.4 mg) and the trachea was extubated. The patient was sent to the  intensive  care  unit  (ICU)  with  oxygen  (10  L/min)  supplementation  by  facemask.  For  mainte-nance  of  fluid,  intravenous  crystalloids  were  given  at  2  mL/kg/hr.  Her  vital  signs  were  acceptably  maintained with  heart  rate  78−84 beats/min,  BP 140−150/80−90 mmHg, CVP 10−12 mmHg, and SpO2 90−95%.  Analgesia  was  provided  by  epidural  ad-ministration of morphine 3 mg diluted in 8 mL of 0.1% of bupivacaine every 12 hours. For thromboproph-ylaxis,  low  molecular  weight  heparin  20  mg  was  given subcutaneously at 12-hour intervals.

After an uneventful 2-day stay in the ICU, she was transferred to the high dependency unit. Epidural and central venous catheters were removed on the 5th postoperative day. The patient was returned to the ward on the 6^th postoperative day where oxygen supplementation (5−6 L/min) was continued. She was weaned from oxygen gradually in the next 2 weeks and discharged home on postoperative day 21.

3. Discussion

We report the successful anesthetic management of a  pregnant  woman  with  Eisenmenger’s  syndrome,  who  underwent  cesarean  section  under  general  anesthesia  with  isoflurane  conveyed  by  PLMA,  in  conjunction with epidural analgesia.

The primary anesthetic goal in such a patient is to minimize  pulmonary  vascular  resistance  (PVR)  sec-ondary  to  hypercarbia,  hypoxia,  acidosis,  stress,  pain and to avoid any hemodynamic changes that might  increase  the  right  to  left  shunt,  thereby  increasing the severity of hypoxemia.⁵

Most patients with this syndrome survive until the second or third decade of life.² Pregnancy should be avoided,^2,4,5 or medical termination is preferred for  women  who  become  symptomatic  in  early  pregnancy.^2,5  The  maternal  mortality  rate  associ-ated  with  cesarean  section  in  the  presence  of  Eisenmenger’s  syndrome  is  30−50%.⁵⁻⁷  Heart  fail-ure,  thromboembolism,  and  bleeding  at  delivery  have been considered as portents of an unfavora-ble prognosis.^1,2 Sudden death is probably the re-sult  of  an  abrupt  rise  in  PVR  or  fall  in  systemic  vascular resistance (SVR).^2,6

The thromboembolic phenomenon results from a  hypercoagulable  state.²  In  the  intrapartum  and  early  postpartum  period,  widespread  fibrin  and  platelet thrombi occlude the already narrowed pul-monary  arteries  resulting  in  an  increased  right  to  left  shunt.² This  has  been  attributed  to  reduced  levels of antithrombin III, protein C and protein S, as  well  as  to  increased  levels  of  fibrinogen,  pro-thrombin, factor VII, VIII, X, antithrombin II and III.⁸ Heparin is the anticoagulant of choice.^2,3,6 Cyanosis is  another  factor  carrying  a  thromboembolic  risk  because  of  polycythemia  and  increases  the  risk  of  fetal loss  (if  oxygen  saturation  is  ≤  85%)  or  intra-uterine  growth  restriction.  Worsening  of  maternal  hypoxemia  is  explained  by  the  decrease  in  SVR,  pronounced  pulmonary  arterial  hypertension  and  consequent  increase  in  right  to  left  flow  through  intercavitary communication.²

We  planned  a  cesarean  section  for  delivery  to  avoid  rigorous  hemodynamic  changes  during  labor  and to spare the fetus the risk of hypoxemia second-ary  to  maternal  physical  exertion  (bearing  down  efforts during normal delivery) and hypoxia.

A sympathetic response to laryngoscopy and intu-bation is undesirable in these patients as it increases PVR thus worsening the right to left shunt and hence we preferred placement of PLMA over conventional endotracheal  intubation.  Epidural  anesthesia  can  produce  patchy  or  incomplete  sensory  block  ne-cessitating general anesthesia as reinforcement.⁵

In our patient, we planned anesthetic induction with propofol  mixed  with  ketamine  (ketofol),  as  propofol reduces both PVR and SVR, and the reduc-tion in SVR is sometimes so abrupt and severe that it may worsen the right to left shunt, while ketamine may increase SVR more than PVR and thus reduce the right to left shunt. Ketamine was not used as a sole induction agent as it causes tachycardia, an in-crease  in  myocardial  oxygen  consumption  and  de-crease  in  diastolic  filling  causing  low  coronary  perfusion  and  decreased  cardiac  output.  Also,  it  hampers uteroplacental blood flow. Thus, we admin-istered  ketofol  to  counteract  propofol-induced  side  effects  such  as  bradycardia  and  hypotension  and, in addition, the analgesic effect of ketamine reduces the opioid requirement.

We used isoflurane in place of sevoflurane be-cause of its less marked myocardial depressive and vasodilatory  effects.⁹  Isoflurane  causes  less  de-pression  of  the  baroreceptor  reflex  as  compared  with  other  inhalational  agents  such  as  halothane  and  enflurane.¹⁰  At  high  concentration,  sevoflu-rane  decreases  coronary  flow  as  it  induces  hypo-tension without coronary vasodilation. Sevoflurane induces more pronounced tachycardia than isoflu-rane at low concentrations which would have been undesirable in this case.¹¹

We used CVP and not pulmonary artery pressure as  the  reference  parameter  in  our  patient  as  she  had right ventricular failure (right ventricular pres-sure 133  mmHg)  because  of  severe  pulmonary  hy-pertension  (70  mmHg).  The  right  ventricle  was  continuously working against high PVR thus increas-ing the risk of failure. The left ventricle was work-ing against a normal SVR and so was not at risk of failure. In such a patient, a right to left shunt may increase when CVP is less than 8 mmHg, which may be further exaggerated by pain. Thus, by providing optimal  preload  (CVP  8−12  mmHg)  and  adequate  analgesia,  we  were  able  to  minimize  the  magni-tude of the right to left shunt.

In  a  patient  with  pulmonary  hypertension  and  an ASD, the change from breathing air to breathing 100%  oxygen  is  nearly  always  associated  with  an  increase in the flow of blood through the pulmonary circuit  and  decrease  of  pressure  in  the  pulmonary  artery.²  As  our  patient  was  in  right  heart  failure  and  had  tricuspid  regurgitation,  we  kept  her  in  the  left  lateral  position  with  30º  head-up  tilt  to keep the right heart pressure lower by decreas-ing  the  preload,  and  to  maintain  uteroplacental  circulation.

The  PLMA  was  inserted  in  the  semirecumbent  left lateral position. This avoided a sudden rise of pressure  in  the  failing  right  ventricle  from  an  in-creased preload, which would occur when the pa-tient was positioned supinely or head down.

Epidural analgesia was chosen for perioperative pain⁶  as  it  reduces  PVR  and  SVR  by  sympathetic  block and reduces catecholamine levels, thus caus-ing  less  tachycardia,  less  myocardial  oxygen  con-sumption, and reduction of the right to left shunt.¹² It  also  induces  vasodilatation  to  accommodate  autotransfusion.

Aside  from  oxygen  administration  (as  in  our  case),  patients  may  be  treated  with  various  spe-cific medications to reduce PVR and improve oxy-genation.¹³ With long-term oxygen administration, the  use  of  specific  medications  in  patient  manage-ment is generally palliative. Sildenafil and L-arginine are  effective  in  decreasing  PVR.  L-arginine  is  con-verted into nitric oxide in the body which decreases PVR. Prostacyclin and its analogs such as epoproste-nol  have  also  been  used.  Bosentan,  an  endothelin  receptor antagonist, has been used and it decreases PVR  by  25%.¹⁴  Phenylephrine,  norepinephrine  and  metaraminol have been recommended to prevent a decrease  in  SVR  during  anesthesia,¹⁵  but  they  also  increase  PVR  and  hence  they  were  not  used  in  our  patient.  Prophylactic  use  of  vasopressors  has  not  been recommended because of associated side ef-fects on these patients with an already compromised cardiovascular  system  and  an  unpredictable  and  probably  increased  response  to  potent  vasoactive rugs. However, their immediate availability must be ensured in the perioperative period.¹⁶

We  chose  not  to  give  oxytocin  in  the  form  of  a  bolus  injection  because  it  causes  direct  va-sodilatation and reduces SVR with a compensatory increase in heart rate and right to left shunt, and so uterine massage followed by slow oxytocin infu-sion  was  likely  to  be  effective  and  safer  in  this  case.⁵

In conclusion, although pregnancy should be dis-couraged  in  women  with  Eisenmenger’s  syndrome,  careful  and  meticulous  perioperative  planning  is  essential for a successful outcome. The cardiac out-put  must  be  maintained  and  SVR  must  not  be  al-lowed  to  fall.  This  should  ensure  that  there  is  minimal change in the magnitude of the right to left shunt. In our patient, the scenario of Eisenmenger’s syndrome was complicated by biventricular hyper-trophy.  We  achieved  the  goals  in  our  patient  by  application  of  inhalation  general  anesthesia  con-veyed by PLMA in addition to intravenous anesthe-sia  (combination  of  propofol  and  ketamine)  and  epidural analgesia.