Anterior ischaemic optic neuropathy after coronary artery bypass graft: the role of anaemia in diabetics.

PURPOSE: To ascertain factors associated with anterior ischaemic optic neuropathy (AION) following coronary artery bypass graft (CABG) in a Lebanese population. METHODS: A retrospective chart review of consecutive CABG performed over a 5-year period (1995-1999) in one medical centre. A comparison of clinical characteristics was carried out between AION cases and subjects free from AION. The variables analysed included history of diabetes as well as preoperative, intraoperative, or postoperative values of haematocrit, blood sugar, oxygen saturation, and arterial blood pressure. RESULTS: A total of 1,594 persons were included. Three subjects experienced acute visual loss from AION following CABG, all had diabetes mellitus, and two suffered from severe postoperative anaemia. Among diabetics (n=484), the risk of AION was significantly higher in subjects with postoperative haematocrit falling below 22 (28.6%) than the rest (0.21%) (P=0.001). Blood transfusion was given in two subjects with prompt visual recovery. CONCLUSIONS: Severe anaemia in patients undergoing CABG appears to be a risk factor for AION, especially in diabetics, and needs prompt correction to prevent or reverse the ischaemic ocular events.

Ocular pathology in congenital heart disease.

PURPOSE: To describe the ocular findings in subjects with congenital heart disease (CHD). METHODS: In a prospective study, the same observer examined 240 consecutive patients with CHD admitted to the medical centre. Two independent geneticists performed identification of syndromes. RESULTS: The commonest anatomic cardiac anomalies were ventricular or atrial septal defects (62), tetralogy of Fallot (39), pulmonary stenosis (25), and transposition of the great arteries (24). The heart lesions were divided physiologically into volume overload (90), cyanotic (87), and obstructive (63). In all, 105 syndromic subjects included the velocardiofacial syndrome (18), Down's syndrome (17), CHARGE association (6), DiGeorge syndrome (5), Williams syndrome (3), Edwards syndrome (3), Noonan syndrome (3), VACTERL association (2), and Patau syndrome (trisomy 13) (2). The paediatric team recognized 51 patients as syndromic. Two independent geneticists recognized additional 54 patients as syndromic. Positive eye findings were present in 55% (132) and included retinal vascular tortuosity (46), optic disc hypoplasia (30), trichomegaly (15), congenital ptosis (12), strabismus (11), retinal haemorrhages (8), prominent eyes (7), and congenital cataract (6). There was a strong correlation between the retinal vascular tortuosity and both a low haematocrit (P=0.000) and a low arterial oxygen saturation (P=0.002). CONCLUSIONS: Patients with CHD are at a high risk for ocular pathology and need screening for various ocular abnormalities.

An unusual case of hyperkalaemia-induced cardiac arrest in a paediatric patient during transfusion of a 'fresh' 6-day-old blood unit.

A well-recognized complication of the transfusion of red blood cells (RBCs) is hyperkalaemia. This occurs in paediatric or adult patients receiving massive transfusion and can lead to cardiac arrest. Hyperkalaemia may follow the transfusion of 'stored' RBCs and/or haemolysed units, and depends on the quantity and rate of transfusion. We report on an unusual case of hyperkalaemia-induced cardiac arrest during transfusion of a 'fresh' blood unit. A 62-day-old baby girl was scheduled for a construction of a Blalock-Taussig shunt, after the completion of anastomosis, and upon release of vascular control, there was bleeding at the anastomotic site that was controlled with a suture placement. To compensate for the blood loss, a stat order was given for a push of 120 mL of RBCs over 10 min through the inferior vena cava central line. The blood unit was 6 days old and had been gamma-irradiated 48 h earlier. Shortly after the transfusion, the patient's electrocardiogram showed changes typical of hyperkalaemia; she then went into cardiac asystole. The blood unit potassium concentration was 55.3 mmol L-1, which flushed the atrioventricular node during transfusion. This is the first report of a high potassium level found in a 'fresh', less than 7 days old, nonhaemolysed RBC blood unit. The high concentration of potassium in this unit seems to be due to accelerated alterations of the RBC sodium/potassium adenosine triphosphatase pump (Na+/K+ pump), resulting in the release of intracellular potassium. This early and severe alteration of the pump and the unusually high potassium level may be due to as yet unexplained causes, warranting awareness, future investigation and routine saline washing of 'fresh' RBCs for paediatric patients who are candidates for central line transfusion.

Dynamic thoracoplasty for asphyxiating thoracic dystrophy.

The life-saving procedures to expand the chests of infants born with Jeune asphyxiating thoracic dystrophy provide a static solution incapable of responding to the growth demands of thriving patients. We describe an instrument that provided a dynamic solution for an infant, where an initial methyl methacrylate midsternotomy spacer placed at 4 months of age was followed at 11 months with recurrence of his difficulties. At 8 months after the second operation the patient was stable and thriving with no recurrence of symptoms. The instrument modifications, limitations, and possible complications are described.

Traumatic pseudoaneurysm of the left sinus of Valsalva: a case report.

Deceleration injuries of the aorta result in tears that often lead to exsanguinating hemorrhage. The site is most often at the aortic isthmus, with injuries of the aortic root being rare. A minority of patients survive long enough to reach the hospital where prompt diagnosis and treatment are essential for survival. We hereby report on a patient who had a pseudoaneurysm of the left sinus of Valsalva 13 years after a deceleration accident, presumably caused by a contained rupture of the aortic root. Transesophageal echocardiography was of great value in studying the features of the pseudoaneurysm and its relation to the left main coronary artery and left upper pulmonary vein.

Perioperative spinal canal narrowing in patients with Down's syndrome.

Two patients with Down's syndrome undergoing intracardiac operations had segmental and generalized myoclonic movements postoperatively and eventual brain death. Electroencephalography in 1 patient showed no seizure despite the presence of the myoclonic movements. Computed tomographic scan showed possible cerebellar hemorrhage. Ultrasound showed cerebral edema when the pupils became fixed and dilated. Because known postoperative neurologic complications could not fully explain the clinical course, and the myoclonic movements suggested spinal origin, we considered the possibility of atlantoaxial instability causing spinal cord damage related to perioperative head and neck positioning. Postmortem study on the second patient revealed 50% reduction of the spinal canal with hyperextension and 90-degree external rotation of the head and neck. In contrast, similar maneuvers in 3 infants without Down's syndrome resulted in only mild spinal canal narrowing. Although the myoclonic movements could be explained by spinal cord compression at the atlantoaxial level, the explanation for the eventual brain death is unclear. However, kinking of the vertebral arteries related to the positioning could have caused cerebellar ischemia, hemorrhage, and increased intracranial pressure. We believe that attention to the problem might bring further answers in the future.