Time course of trough serum gentamicin concentrations in preterm and term neonates.

Trough serum concentrations (Cmin) of gentamicin were followed during up to 96h of treatment in 44 neonates (17 preterm and 27 term), treated with intramuscular gentamicin 2.5 +/- 0.3 mg/kg (mean +/- SD) twice daily, a dosage that was not changed during the follow-up period. Relationships with patients' gestational age, postnatal age, postconceptional age and bodyweight were analysed to identify circumstances in which gentamicin should be monitored. Gentamicin Cmin values after 24h correlated better with neonate's postconceptional age (r = -0.42) or gestational age (r = -0.37) than with postnatal age or bodyweight. Correlations with postconceptional age and gestational age improved after 96h (r = -0.71 and r = -0.67, respectively). From 24 to 96h Cmin increased from 1.5 to 2 mg/L (p < 0.001) in the preterm neonates and from 1.5 to 2.5 mg/L (p < 0.01) in those preterm neonates < or = 32 weeks of gestational age, while differences between neonates < or = 3 days and > 3 days of postnatal age were nonsignificant. The Cmin at 24h was potentially toxic (> 2 mg/L) in 9% of the neonates (12% of preterm and 7% of term neonates). At 96h, the percentage of neonates with toxic Cmin values increased to 25% (65% of all preterm neonates and 100% of preterm neonates < or = 32 weeks of gestational age), whereas in term neonates it decreased to 0%. In conclusion, in preterm neonates < or = 32 weeks of gestational age a dosage of 2.5 mg/kg every 24h should be used, and gentamicin concentrations should be monitored. However, in term neonates > 7 days of postnatal age a dosage of 3.5 mg/kg twice daily should be recommended.

Anatomically corrected malposition (surgical repair).

Anatomically corrected malposition is a rare anomaly usually associated with other complex malformations. However, less complicated cases do occur and we report one such case treated surgically with success. Our experience underlines the importance of careful digital examination of the right ventricle from the atrium to determine the position of the septum, as the position of the left anterior descending coronary artery can be misleading.

[The use of cryopreserved homografts in reconstructing the right ventricular outflow tract in congenital cardiopathies]. / La utilización de homoinjertos crioconservados en la reconstrucción del tracto de salida del ventrículo derecho en cardiopatías congénitas.

In recent years the use of cryopreserved allograft valves has become very popular. Homograft valves have been used for aortic valve replacement and for reconstruction of the outflow tract of the right ventricle for more than 30 years with very good results. Recently the method of cryopreservation has made possible the creation of valve banks. The use of this cryopreserved valves has obtained very good short and medium term results. We present our experience with the use of cryopreserved allograft valves in the reconstruction of the right ventricular outflow tract in the treatment of complex cardiac malformations. We have operated 15 children. Six were diagnosed of different types of transpositions of the great arteries with ventricular septal defect and pulmonary atresia or stenosis. There were 2 deaths not related to the use of the allograft valves. Nine other patients were diagnosed of different types of complex cardiac malformations. One patient with a univentricular heart and pulmonary stenosis and a neonate presenting with a truncus arteriosus communis died after the operation; again the deaths were not related to the use of the homograft conduits. Our technique of cryopreservation consists in the procurement of aortic and pulmonary valves from multiorgan donor patients. The valves are sterilized in antibiotics for 48 hours. Then the process of freezing is began with a period of progressive cooling down to -40 degrees C and second phase of storage in liquid nitrogen to a temperature of -178 degrees C. The short and medium term results are very satisfactory. We have not seen late important complications.

[Anomalous origin of the right pulmonary artery from the ascending aorta. Its surgical correction in early infancy]. / Origen anómalo de la arteria pulmonar derecha de la aorta ascendente. Corrección quirúrgica en la primera infancia.

Anomalous origin of the right pulmonary artery from the ascending aorta is a rare congenital malformation associated with a high mortality during the first year of life. Up to 1990, 75 cases have been reported in the literature. We are reporting 2 cases diagnosed and operated before 3 months of age. Repair was facilitated by the use of deep hypothermic circulatory arrest. The duration of follow up is 5 and 6 years, respectively. Pre and postoperative cardiac catheterization pressure data and angiograms are shown. We review the literature, presenting the physiopathological, embryological and surgical features of this rare congenital anomaly.

[The anatomical correction of transposition of the great arteries in the neonatal period]. / Corrección anatómica de la transposición de grandes arterias en período neonatal.

INTRODUCTION AND OBJECTIVES: Anatomic correction of transposition of the great arteries in simple and complex form is theoretically the only procedure which offers the possibility of real cure to the problem. We report there our operative results and mid-term follow-up with this approach. METHODS: From June 1989 to February 1994, anatomical surgical correction was performed in 41 patients in the neonatal period, 31 with simple TGA and 9 patients with transposition associated with ventricular septal defect. We report our preoperative management, anatomic findings and surgical technique. RESULTS: Our initial experience with the arterial repair was associated with a high operative mortality. The actuarial survival rate was 74% at 56 months. Hospital mortality of the last 31 patients was 12.9%. Intermediate-term follow-up was 18 months. No late deaths. One patient underwent reoperation for supravalvular pulmonary stenosis. All survivors are in functional class I. The only significant risk factor of in-hospital mortality was the time of surgery (learning curve). CONCLUSION: The initial experience with arterial repair is associated with a difficult learning curve. Primary repair must be performed during the newborn period in simple and complex transpositions. Mid-term results are very encouraging. Longer follow-up is necessary to secure this technique and to render obsolete all other types of repair.

[Palliative arterial switch]. / Switch arterial paliativo.

We report the first case published in Spain of a palliative anatomic correction associated with aortic arch repair in a neonate with (S,D,L)-transposition of the great arteries, multiple ventricular septal defects, and severe hypoplasia of the right ventricle with subaortic obstruction and hypoplasic aortic arch with coarctation. A one stage palliative surgery on cardiopulmonary bypass was performed with reconstruction of the aortic arch and an arterial switch procedure which obtained a satisfactory result. The principle of this operation is to switch the subaortic obstruction into a subpulmonary obstruction and reconstruct a large natural aortic root from the principal ventricle. The right ventricle-pulmonary artery continuity may promote growth of the right ventricle with the possibility of a future biventricular repair. We conclude that this operation, when used by surgical teams experienced with arterial switch surgery, is the best treatment for the complex newborn group with single ventricles or severe ventricular disbalance, ventriculoarterial discordance and stablished subaortic stenosis.

[Risk factors in the Glenn bidirectional shunt as an intermediate procedure before Fontan correction]. / Factores de riesgo en el shunt de Glenn bidireccional como proceder intermedio antes de la corrección de Fontan.

OBJECTIVE: The bidirectional Glenn shunt is the most common palliation before the Fontan repair, especially in high-risk patients. We studied the influence of certain risk factors in bidirectional Glenn results, with and without an additional source of pulmonary blood flow. METHODS: Between 1993 and 1998 twenty patients (6-53 months of age) underwent a bidirectional Glenn shunt as the intermediate repair for the Fontan procedure. Diagnoses were: 7 cases of double inlet single ventricle, 4 of tricuspid atresia, 3 of unbalanced AV septal defect, 4 of mitral atresia, 1 hypoplastic left heart syndrome and 1 TGA with hypoplasia of the right ventricle. 17 patients had undergone previous operations. Mean preoperative arterial oxygen saturation was 78.5%. In 6 patients an auxiliary source of pulmonary blood flow was added. RESULTS: Hospital mortality was 15%. In 4 patients the bidirectional Glenn failed. By univariate analysis low weight, preoperative functional status and high pulmonary pressure were factors associated with early death. In bidirectional Glenn failure only the duration of ventilatory support was significant. By multivariate analysis, preoperative functional status and pulmonary pressure were significant. Mean postoperative arterial oxygen saturation at a mean follow-up of 10 months was 84%. CONCLUSIONS: Bidirectional Glenn shunt is an effective and low-risk palliation for patients with univentricular hearts. Only low weight and high pulmonary pressure were significant in hospital mortality, and we advise the association of an additional source of pulmonary blood flow in these patients at the start. Early extubation provides correct performance of the shunt.

[Results of three different stapedectomy techniques: a comparative study]. / Estudio comparativo de los resultados de tres tipos diferentes de estapedectomía.

We perform a comparative study on the results obtained through three stapedectomy techniques. The hearing gain was evaluated in 107 ears with total footplate removal, Shea prosthesis and connective tissue graft, in 81 ears with particular footplate removal, the same prosthesis, and no tissue graft, and in 66 ears with stapedectomy. The differences between the three groups in the air-bone gap closure or postoperative complications were not statistically significant. We conclude that results depend more on the surgeon than on the technique.

[Program of hearing loss early detection in newborn infants in Cantabria. Results of the first year of activities]. / Programa de detección precoz de la hipoacusia en neonatos en Cantabria. Resultados del primer año de funcionamiento.

AIMS: To report the findings in the first year of follow-up of the Cantabrian Program to screen newborn babies for congenital permanent hearing loss. METHODS: The study population consisted of infants born during a year period in Cantabria (Spain). Universal hearing screening by transient evoked otoacoustic emissions (TEOAE) in 2 stage protocol was performed. Infants with failure scores in these 2 stages and those with risk factors for hearing loss were referred for diagnostic evaluation with auditory brainstem response. Hearing aids were recommended for those infants who had bilateral hearing loss and referrals to infant speech and language rehabilitation. RESULTS: Out of the 4117 eligible babies, 3987 were studied. One hundred and ten (2.6) had risk factors for hearing loss, 3.5% were referred for audiological assessment and 1.2/1000 were diagnosed as having a permanent hearing loss. The false-positive rate was 0.72% after the two-stage screening procedure was performed. Positive predictive value for permanent hearing loss was 10%. CONCLUSIONS: During the first year working with the Cantabrian Screening Program for congenital permanent hearing loss in newborn babies, the most part of the proposed aims have been achieved.