Lynda J. Means

Dilutional And Modified Ultrafiltration Reduces Pulmonary Hypertension After Operations For Congenital Heart Disease: A Prospective Randomized Study

OBJECTIVE A prospective randomized study was performed to test whether removal of endothelin-1, by ultrafiltration techniques, will reduce pulmonary hypertension after operations for congenital heart disease. METHODS Twenty-four patients with pulmonary hypertension (systolic pulmonary/systemic arterial pressure ratio > 60%) undergoing cardiac operations were randomized into a control group (n = 12) having conventional ultrafiltration and an experimental group (n = 12) undergoing dilutional ultrafiltration during and modified ultrafiltration after cardiopulmonary bypass. Plasma endothelin-1, nitric oxide metabolites, and cyclic guanosine monophosphate were assayed before bypass, 10 minutes into bypass, after bypass, and 0, 3, 6, and 12 hours after the operation in both groups, as well as in the ultrafiltrates and after modified ultrafiltration in the experimental group. Both groups received alpha-blockers (chlorpromazine and/or prazosin) postoperatively using the same guidelines. RESULTS The ultrafiltrates contained significant amounts of endothelin-1 (1.81 +/- 0.86 pg/ml, dilutional, and 6.44 +/- 1.82 pg/ml, modified ultrafiltrate). Endothelin-1 and the pulmonary/systemic pressure ratio were significantly lower in experimental compared with control patients. Nitric oxide metabolites and cyclic guanosine monophosphate increased similarly in both groups for 12 hours after the operation (p = not significant). Three of 12 control patients (25%) but no experimental patients had pulmonary hypertensive crises (p = 0.07). The experimental patients required significantly less ventilatory support (67 +/- 47 hours vs 178 +/- 139 hours for control patients, p = 0.048). CONCLUSIONS Dilutional and modified ultrafiltration reduce endothelin-1 and the pulmonary/systemic pressure ratio postoperatively and may become an important adjunct for preventing pulmonary hypertension after operations for congenital heart disease in high-risk patients.

Cardiac transplantation in infants and children

Cardiac transplantation has become a more frequently used therapeutic modality for select cardiac pathology in infants and children. Since June 1986, 30 pediatric patients (19 male and 11 female) ranging in age from 4 days to 15 years (11 < or = 1 month old) have undergone orthotopic cardiac transplantation at our institution. Indications included idiopathic cardiomyopathy (n = 8), hypoplastic left heart syndrome (n = 13), and other forms of complex congenital heart disease (n = 9). There have been four operative and three late deaths only in the groups with hypoplastic left heart syndrome and other forms of complex congenital heart disease. Cumulative survival is 77% after a mean follow-up of 30 months (range, 6 to 77 months). Three operative deaths were attributable to pulmonary hypertension, and the other was due to pulmonary hemorrhage. Two late deaths were secondary to allograft rejection, and the third was due to infection. There has been uniform survival in the group with idiopathic cardiomyopathy, and intermediate-term survival rates are 78% and 62% in the groups with complex congenital heart diseases and hypoplastic left heart syndrome, respectively (p = 0.15). Although longer-term results are necessary, orthotopic cardiac transplantation appears to be an acceptable mode of therapy for endstage heart disease in the pediatric age group and technically can be performed despite complex malformations of the great arteries or atria.

Iodine toxicity: An unusual cause of cardiovascular collapse during anesthesia in an infant with Hirschsprung's disease

This report describes a case of acute life-threatening iodine toxicity in an infant with Hirschsprungs disease caused by rectal irrigation with povidone-iodine. A hypothesis regarding absorption and recommendations for povidone-iodine usage for bowel preparation are presented.

Latex anaphylaxis: Report of occurrence in two pediatric surgical patients and review of the literature

This report describes two cases of intraoperative anaphylaxis in children sensitized to latex. Both children were undergoing nonurological procedures and, despite numerous previous operations, neither had a history of unusual reaction or anaphylaxis during surgery. The problem of latex allergy is discussed with review of the current literature and suggestions for management.

Pulmonary capillary recruitment in neonatal lambs

ABSTRACT: In species having lungs large enough to develop hydrostatic perfusion zones, increased pulmonary arterial pressure causes blood flow to be redistributed from the lower to the upper lung. The blood flow increase in the upper lung recruits capillaries and increases gas exchange surface area. There is disagreement, however, about whether such capillary recruitment occurs in young animals with small lungs. To investigate this issue, we used in vivo microscopy to directly study capillary perfusion in individual alveolar walls in the upper lungs of neonatal lambs and in older lambs with larger lungs. Pulmonary arterial pressure was elevated by airway hypoxia. In neonatal lambs (<10 d old; n = 7), hypoxia increased pulmonary arterial pressure by 55% but did not cause capillary recruitment. In older lambs (20–61 d old; n = 6), hypoxia increased pulmonary arterial pressure by 40% and caused a 46% increase in recruited capillaries. These results support the hypothesis that capillary recruitment does not occur in newborn lambs when pulmonary arterial pressure increases and implies that there is limited gas exchange reserve. In older lambs, however, gas exchange reserve develops through recruitable capillaries as the lungs mature.

Sublingual emphysema complicating dental anesthesia

The introduction of gas into soft tissues during dental procedures has been recognized since 1900 (1). Cases of subcutaneous facial emphysema characterized by rapidly progressing unilateral facial swelling have been reported. To our knowledge localized sublingual emphysema without facial involvement after a dental procedure has not been reported. We present two cases of sublingual emphysema, and discuss the etiology and potential hazards of this syndrome.