|Year : 2008 | Volume
| Issue : 6 | Page : 853
Cardiac Catheterization in Thoraco-Omphalocardiopagus Twins: A Case Report
Minati Choudhury1, Usha Kiran2
1 Associate Professor, Department of Cardiac Anaesthesia, Cardiothoracic Sciences centre, All India Institute of Medical Sciences, New Delhi-110029, India
2 Professor & HOD, Department of Cardiac Anaesthesia, Cardiothoracic Sciences centre, All India Institute of Medical Sciences, New Delhi-110029, India
|Date of Acceptance||28-Oct-2008|
|Date of Web Publication||19-Mar-2010|
Department of Cardiac Anaesthesia, Cardiothoracic Sciences centre, All India Institute of Medical Sciences, New Delhi-110029
Source of Support: None, Conflict of Interest: None
The incidence of conjoined twin is rare and anaesthesia for procedures on conjoined twins is a demanding, exacting and meticulous exercise, whether prior to or during separation.
literature on the anaesthetic management of these cases is sparse. The following case report details the expert and vigilant anaesthetic management leading to successful diagnostic cardiac catheterization. The report emphasizes the importance of synchronous ventilation, teamwork and communication required in cases such as this. This case report also details the difficulties encountered and how to overcome them during the prolonged procedure.
Keywords: Conjoined twins, Cardiac catheterization
|How to cite this article:|
Choudhury M, Kiran U. Cardiac Catheterization in Thoraco-Omphalocardiopagus Twins: A Case Report. Indian J Anaesth 2008;52:853
| Introduction|| |
The earliest known record of conjoined twins is about the Biddendon girls born in 1100 AD in Kent.  Since then there is increasing number of attempts to surgically separate them. But till today in most of the cases their separation is not feasible. However they continue to fascinate the medical personnel and general public. Recent advances regarding the diagnosis and anaesthetic management of these cases has been introduced in the 1980s. They often have complex cardiovascular anomalies for which a thorough preoperative cardiac evaluation is a must, before taking the decision regarding their separation. , Different anaesthetic techniques have been described by various authors for the management of these cases during their surgical separation. ,, But to our knowledge there is no report regarding the anaesthetic management of these cases during a diagnostic cardiac catheterization procedure which is also not a less challenging one. We describe our experience concerning the management of thoraco-omphalocardiopagus twins during the periods of prolonged cardiac catheterization.
| Case report|| |
A pair of male conjoined twins, twin-1 and twinII was delivered by emergency caesarean section delivery at 39 weeks of gestation. Clinically they were diagnosed as thoraco-omphalocardiopagus [Figure 1] .
The combined weight was 4300 grams (both the twins appeared to have equal weight). The APGAR score of twin-I was 3, 8 and that of twin-II was 6, 8 at 1 and 5 minutes respectively. They were nursed in an incubator and in the meanwhile, investigated and prepared for surgical separation. Haematological and biochemical tests were found to be within normal limits [Table 1] and approximately equal in both the twins. Both of them had oxygen saturations of 65-75% on a 4 L.min -1 of flow by oxygen.
Ultrasound abdomen suggested a possible fusion of livers, billiary tract and gut. Due to technical difficulties for stabilizing the echocardiographic transducer, a proper imaging plane could not be obtained. However; the transthoracic echocardiography revealed the presence of two separate double chambered atrium, three ventricles and a close connection between the twins heart. Twin-1 was intubated at the 16 th hours of his birth due to the development of acute respiratory insufficiency and gradually weaned off from ventilatory support within 24 hour period of intubation. Diagnostic cardiac catheterization was planned after their initial stabilization. Both the twins were found to be conscious, active and had spontaneous respiration at the time they were shifted from the paediatric nursery to the cardiac catheterization laboratory. On arrival in the cardiac catheterization laboratory they were found to be tachypnoeic. Vital signs were as follows: Twin-1 had an arterial blood pressure of 69/41 mmHg, a heart rate of 140 beats/minute, a respiratory rate of 60-70 breaths / minute, an oxygen saturation of 65% and was afebrile. Twin-II had an arterial blood pressure of 55/30 mmHg, a heart rate of 156 beats/minute, a respiratory rate of 70-80 breaths/minute, an oxygen saturation of 70% and was also afebrile.
Continuous monitoring of oxygen saturation (SpO 2 ), blood pressure, electrocardiogram (ECG) was started in both of them. Two sets of ECG electrodes were applied, at the back of each twin. ECG revealed the presence of two 'P' waves overlapping with each other but a single QRS complex. Twin-1 had already a patent intravenous line to which maintenance fluid chamber was connected. Another 22 gauge intravenous catheter was inserted on twin-II's right hand. Both the twins were allowed to breathe spontaneously with O2: air at the ratio of 50:50 from the system. After preoxygenation for five minute 8 mg of ketamine and 0.6 mg of vecuronium bromide was administered to twin-II. Both of them were found to be paralyzed at the same time. Mask ventilation was started immediately for both of them and intubation was done subsequently followed by artificial ventilation. The twins' position (facing each other, attached chest to chest;[Figure 1] made direct laryngoscopy extremely akward. As the heads were turned to give more room for direct laryngoscopy, there was possible distortion of the laryngeal anatomy. Twin-I was intubated in single attempt with a 3mm size uncuffed portex endotracheal tube whereas we could able to secure twin-II 's'trachea in the fourth attempt. During the process Twin-II developed one bout of laryngospasm which was resolved with mask ventilation and deepening of anaesthesia. Limited space in the cardiac catheterization laboratory forced us to ventilate both the babies from the gas source coming from a single anaesthesia machine. We attached one 'Y' connection at the gas source from the machine end to which two non-rebreathing Jackson-ree's modification of Ayres 'T' piece system were attached [Figure 2]. Both the twins were ventilated manually by one anaesthesiologist.The fresh gas flow was 10 liters/minute. Single dose of morphine hydrochloride (1 mg) was used as the sole analgesic. Anaesthesia was maintained with incremental doses of midazolam and vecuronium bromide. Oxygen: air was administered at the ratio of 40:60. The heart rate, blood pressure and oxygen saturation of both the babies were found to be equal at all the time and maintained near the base line value through out the procedure. The arterial blood gas (ABG) values of both of them were exactly the same at different time intervals and revealed no abnormalities [Table 2]. Cardiac catheterization demonstrated the presence of separate two chambered atrium for both the twins, four ventricles having interconnection between them through septal defects. In addition to these twin-1 had total anomalous pulmonary venous connection and coarctation of aorta. A patent ductus arteriosus and pulmonary stenosis were found in twin-II. Fluid replacement was done according to the blood pressure and central venous pressure monitoring.
Inspite of administration of all the drugs and fluid through twin-II's intravenous line, we did not find any circulatory and ABG disparity at any point of time among the twins. The total duration of the procedure was three hours. At the end, they were found to be conscious, started spontaneous breathing though their effort was not adequate. They were shifted to the cardiac intensive care unit (ICU) and put on SIMV mode and gradually weaned off within 5 hours period. On reaching the ICU the ABG was repeated and no deviation from the base line value was found.
| Discussion|| |
Conjoined twins are said to be the result of an incomplete division of embryo between the thirteenth and fifteenth day of fertilization.  Thoracopagus twins having cardiovascular anomalies account for 75% of the general cases.  A list of authors described the best possible anaesthetic management of these cases during their surgical separation. However, there are no guidelines for the management of these cases during a prolonged cardiac catheterization; which is an important diagnostic mode. This procedure itself is not free of any risk. Major complications included death, myocardial infarction and cerebrovascular complication followed by cardiac perforation, arrhythmia, local vascular problem, vasovagal reaction and allergy due to contrast media. All of these complications are more pronounced in infants, complex cardiac defects, valvular heart disease and left ventricular dysfunction.  Again each case of conjoined twins have its unique differences, hence their clinical behavior during the anaesthetic management may vary from case to case. Sedation without the induction of general anaesthesia has been successfully performed in children for diagnostic cardiac catheterization studies.  However general anaesthesia is often required in high risk patients.  Accordingly, we chose to provide general anaesthesia to those babies with their airway secured with endotracheal tubes.
Administration of anaesthetic agents to one twin led to sedation and paralysis of the other twin which we never expected and not described before. Due to the presence of vigilant team we could able to overcome this problem. Though before the procedure both the twins were haemodynamically stable and oxygenating satisfactorily, still we were in doubt regarding their behavior with anaesthesia induction. Finally, we were unsure how the twins would respond to positive pressure ventilation changes and did not know whether ventilation synchrony was warranted. Review of earlier research revealed that anaesthesia for cardiac catheterization procedure should provide rapid induction and emergence along with a reliable sedation state.  Both intravenous and inhaled anaesthetic agent along with a short acting muscle relaxant may fulfill these requirements.  In addition to the demands of cardiac catheterization laboratory environment, we needed to consider the complex cardiac physiology of the twins.
While studying the effect of different anaesthetic agents in children having complex cardiac anatomy, Rivenes et al found that sevoflurane and isoflurane maintain cardiac output, but both the agents decreased cardiac contractility.  Williams et al stated that in presence of pulmonary hypertension continuous infusion of ketamine anaesthesia for diagnostic cardiac catheterization did not increase the pulmonary vascular resistance in children with severe pulmonary hypertension.  Propofol- ketamine combination has been reported to be a reasonably good combination in catheterization suite in spontaneously breathing children.  However it has been reported to cause a decrease in heart rate.  Opioids, as a result of their haemodynamic stability have been the mainstay of paediatric cardiac anaesthesia for the last few decades. 
Except the general problems faced by a paediatric cardiac anaesthesiologist the major concern in these twins with a shared heart is a complete blood exchange every minute. Due to this reason drugs administered to one infant may have unpredictable effect on other. ,, We agree with the previous authors but differ from them in one aspect that in spite of administration of all the drugs to one of them throughout the period, we did not find any effect due to drug overdose. Their clinical behavior remained the same during the whole course.
Because both the twins required high respiratory rates, it was necessary to hand ventilate both the twins throughout the procedure. Another reason to prefer manual ventilation over mechanical ventilation was for a better appreciation of subtle changes in lung compliance and airway resistance. The ventilation was managed by single anaesthesiologist to maintain synchrony, believing that this would decrease the likelihood of untoward shunting. The major problems which we faced in the cardiac catheterization laboratory were overcrowding, cardiovascular monitoring, difficulty in maintenance of airway and vascular cannulation due to the relative position of the twins. To conserve space, we used only one anaesthesia machine and single anaesthesia team (two anaesthesiologists).
In summary, the basic principles of optimal anaesthetic management during cardiac catheterization of thoraco-omphalocardiopagus twins (eg. airway, preservation of body temperature, cardiovascular stability) are the same as their management during the surgical separation. Above all to these, addition and titration of drug doses, choice of anaesthetic agents, ventilation pattern too carries a major role for the accurate diagnosis and interpretation of the catheterization data.
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[Figure 1], [Figure 2]
[Table 1], [Table 2]