IT is believed that complete heart block is unlikely to occur in patients without preexisting left bundle branch block. We describe the occurrence of complete heart block during attempted placement of a central venous catheter in a child with mucopolysaccharidosis (MPS) type VII (Sly syndrome) without preexisting left bundle branch block. Numerous reports of anesthesia in patients with MPS have described airway management and respiratory complications. However, cardiac problems during anesthesia in patients with MPS should be considered important because of the possibility of preexisting cardiomyopathy or coronary stenosis.
The patient was a 4-yr-old girl with MPS type VII. Patient height and weight were 92 cm and 13 kg, respectively. She was born in the 36th week of pregnancy, and her weight at delivery was 2,552 g. She underwent phototherapy and an exchange blood transfusion for icterus neonatorum and polycythemia. The patient had retarded speech and motor development, gargoyle facies, and hepatosplenomegaly. Consequently, she was diagnosed with MPS type VII. At the age of 3 yr, echocardiography was performed because of hypertension (blood pressure, 160/90 mmHg), and angiography revealed severe stenosis of the aorta from the descending to the abdominal part, which is called atypical coarctation of the aorta. After a preoperative examination, the child underwent uneventful aortic bypass grafting from the descending to the abdominal part without an intracardiac procedure on January 14, 2000. No difficulty in intubation was encountered. Postoperatively chest radiography revealed pulmonary atelectasis, and the bronchi were often occluded by viscous sputum. Therefore, mechanical ventilation was maintained, and physiatric intervention was performed for 5 days. The patient was discharged from the intensive care unit 7 days later.
On March 14, 2000, when she was 4 yr old, she was readmitted for bone marrow transplantation because of MPS and was scheduled to undergo insertion of a subcutaneously tunneled central venous catheter during general anesthesia. Her blood pressure was 138/72 mmHg, and no abnormal values were observed in routine preoperative blood tests. No abnormalities, including atelectasis, were revealed by preoperative radiography. The electrocardiogram showed left ventricular hypertrophy but did not reveal any conduction defects.
The patient was premedicated with 3 mg oral midazolam 30 min before anesthesia. Her blood pressure and heart rate were 160/76 mmHg and 140 beats/min, measured by cuff and electrocardiograph, respectively, before anesthesia induction. Anesthesia was cautiously induced with 5% sevoflurane and nitrous oxide in 50% oxygen. A peripheral intravenous catheter was placed on the dorsum of the left hand. Systolic blood pressure of approximately 160 mmHg was observed during induction of anesthesia. Anesthesia was maintained with 1% inhaled sevoflurane via face mask, with spontaneous assisted ventilation. Oxygen saturation (Spo2) and expired carbon dioxide (PETco2) were continuously measured, and there was no evidence of hypoxia or hypercapnia during the procedure. A Hickman®7-French dual lumen central venous catheter (C.R. Bard, Salt Lake City, UT) was selected because long-term catheter placement was expected in this patient. The subclavian approach was used after injection of topical lidocaine. The subclavian vein was readily accessible. Thereafter, the guide wire was smoothly inserted and advanced to the superior vena cava during fluoroscopic control. We tried but failed to insert the introducer with vessel dilator because of difficulty negotiating the infraclavicular space. After a while, blood pressure suddenly decreased to 50 mmHg, and heart rate decreased to 65 beats/min. Nitrous oxide and sevoflurane were discontinued, the fraction of inspired oxygen (Fio2) was increased to 1.0, and 0.2 mg atropine was administered intravenously. Fluoroscopy revealed that the guide wire had entered the right ventricle; thus, it was withdrawn into the superior vena cava. Despite subsequent intravenous atropine administration (total dose, 3 mg) and 4 mg ephedrine administration, the patient’s heart rate decreased to 40 beats/min, and blood pressure was not measurable. The electrocardiogram displayed complete heart block. Cardiac compression was initiated, and the trachea was intubated without difficulty. Fifty micrograms epinephrine was administered intravenously, but circulatory collapse continued. Because hypotension and bradycardia had continued for approximately 10 min, resuscitation had been continued all the while. After administration of an additional 50 μg epinephrine, the patient was successfully resuscitated. Blood pressure increased to 170/94 mmHg, and heart rate increased to 108 beats/min. Immediately after resuscitation, arterial blood gas analysis showed a pH of 7.226, an arterial carbon dioxide tension (Paco2) of 29.1 mmHg, an arterial oxygen tension (Pao2) of 463.3 mmHg, and a bicarbonate concentration of 11 mm. Sodium bicarbonate was administered for treatment of metabolic acidosis.
Attempts to insert the Hickman®catheter were aborted. A conventional central venous catheter was introduced into the right internal jugular vein without difficulty. No abnormalities, including pneumothorax and hemothorax, were evident from postoperative chest radiography. After the procedure, the patient’s trachea remained intubated, and she was subsequently transferred to the intensive care unit. She regained consciousness at the time of her arrival in the intensive care unit, and her trachea was then successfully extubated. The postoperative course was uneventful, and her consciousness level was similar to that observed preoperatively. Postoperative electrocardiography did not show any changes compared with the preoperative tracing.
Previous reports 1–3have shown that airway management during anesthesia is important in patients with MPS. However, cardiovascular complications during anesthesia in patients with MPS have been described in only a few reports. Cardiovascular complications should be considered as a potential consequence of valvular insufficiency, cardiomyopathy, and coronary stenosis. Belani et al. 4described the occurrence of cardiac arrest in two patients with Hurler syndrome. In both cases, autopsy revealed almost complete occlusion of the coronary arteries. Furthermore, Okada et al. 5reported that infiltration of the cardiac conduction system by gargoyle cells was present at the time of autopsy in patients with MPS.
Sinus bradycardia followed by complete heart block was most likely a consequence of guide wire–induced trauma of the conduction system, including the atrioventricular node, the His bundle, and the right bundle branch. Complete heart block was difficult to reverse because of possibly associated disease in the coronary arteries and the conduction system in the current patient. Eissa and Kvetan 6reported a case of complete heart block caused by direct trauma to the His bundle. Sprung et al. 7described a case of complete heart block during pulmonary artery catheterization. They suggested that the conduction system may have been compromised by ischemia caused by coronary disease. Although it is believed that the risk of complete heart block is higher in patients with left bundle branch block than in patients without this conduction disturbance, Castellanos et al. 8reported a case of left bundle branch block during right-sided heart catheterization. Therefore, complete heart block may occur in patients without preexisting left bundle branch block. In the current patient, coronary blood flow most likely decreased as a result of hypotension secondary to sinus bradycardia and then complete heart block; this may have been aggravated by coronary narrowing. Additionally, despite descending aortic bypass grafting, hypertension was still present in the patient. This may have led to altered autoregulation such that the decrease in blood pressure noted may have compounded the decrease in coronary blood flow, causing severe ischemia of the gargoyle-infiltrated conduction system. Cautious advancement of the guide wire by more vigilant fluoroscope use would have prevented this morbidity if the guide wire had been prevented from entering the right side of the heart.
In conclusion, we describe the anesthetic management in a child with MPS type VII. Previous reports have emphasized airway precautions. In this report, we alert clinicians to the likelihood of cardiac complications.