Intracellular activities of chloride, potassium and sodium ions in rabbit corneal epithelium.

The mechanism of ion transport in the epithelium of rabbit cornea was studied by determining the intracellular ion activity of Cl-, Na+ and K+ under various conditions. Ionic activities were measured by means of microelectrodes containing liquid ion-exchangers selective for Cl-, Na+ or K+. The Cl- activity in basal cells of the epithelium in Na+ containing bathing solutions amounts to 28 +/- 2 mM (n = 11). This value is 1.9-times greater than expected on the basis of passive distribution across the tear side membrane. This finding suggests the existence of a Cl- accumulating process. Replacement of Na+ in the aqueous bathing solution by choline or tetraethylammonium results in a reversible decrease in Cl- activity to 22 +/- 1 mM (n = 11, P less than 0.025). The ratio of observed and predicted Cl- activity decreased significantly from 1.9 to 1.4 (P less than 0.05). The decrease in Cl- activity due to Na+ replacement was rather slow. In contrast, after readmittance of Na+ to the aqueous bathing solution, Cl- activity rose to a stable level within 30 min. These results indicate involvement of Na+ in Cl- accumulation into the basal cells of the epithelium. The K+ and Na+ activities of the basal cells of rabbit corneal epithelium in control bathing solutions were 75 +/- 4 mM (n = 13) and 24 +/- 3 mM (n = 12), respectively. The results can be summarized in the following model for Cl- transport across corneal epithelium. Cl- is accumulated in the basal cells across the aqueous side membrane, energized by a favourable Na+ gradient. Cl- will subsequently leak out across the tear side membranes. Na+ is extruded again across the aqueous side membrane of the epithelium by the (Na+ + K+)-ATPase.

Cerebral oxygenation and hemodynamics during induction of extracorporeal membrane oxygenation as investigated by near infrared spectrophotometry.

OBJECTIVE: To investigate cerebral oxygenation and hemodynamics in relation to changes in some relevant physiologic variables during induction of extracorporeal membrane oxygenation (ECMO) in newborn infants. METHODS: Twenty-four newborn infants requiring ECMO were studied from cannulation until 60 minutes after starting ECMO. Concentration changes of oxyhemoglobin (cO2Hb), deoxyhemoglobin (cHHb), total hemoglobin (ctHb), and (oxidized-reduced) cytochrome aa3 (cCyt.aa3) in cerebral tissue were measured continuously by near infrared spectrophotometry. Heart rate (HR), transcutaneous partial pressures of oxygen and carbon dioxide (tcPO2 and tcPCO2), arterial O2 saturation (saO2), and mean arterial blood pressure (MABP) were measured simultaneously. Intravascular hemoglobin concentration (cHb) was measured before and after starting ECMO. In 18 of the 24 infants, mean blood flow velocity (MBFV) and pulsatility index (PI) in the internal carotid and middle cerebral arteries were also measured before and after starting ECMO using pulsed Doppler ultrasound. RESULTS: After carotid ligation, cO2Hb decreased whereas cHHb increased. After jugular ligation, no changes in cerebral oxygenation were found. At 60 minutes after starting ECMO, the values of cO2Hb, saO2, tcPO2, and MABP were significantly higher than the precannulation values, whereas the value of cHHb was lower. There were no changes in cCyt.aa3, tcPCO2, and HR, whereas cHb decreased. The MBFV was significantly increased in the major cerebral arteries except the right middle cerebral artery, whereas PI was decreased in all measured arteries. Cerebral blood volume, calculated from changes in ctHb and cHb, was increased in 20 of 24 infants after starting ECMO. Using multivariate regression models, a positive correlation of delta ctHb (representative of changes in cerebral blood volume) with delta MABP and a negative correlation with delta tcPO2 were found. CONCLUSIONS: The alterations in cerebral oxygenation after carotid artery ligation might reflect increased O2 extraction. Despite increase of the cerebral O2 supply after starting ECMO, no changes in intracellular O2 availability were found, probably because of sufficient preservation of intracellular cerebral oxygenation in the pre-ECMO period despite prolonged hypoxemia. The increase in cerebral blood volume and cerebral MBFV may result from the following: (1) reactive hyperperfusion, (2) loss of autoregulation because of prolonged hypoxemia before ECMO and/or decreased arterial pulsatility, or (3) compensation for hemodilution related to the ECMO procedure.

Management of pediatric esophageal perforation.

Esophageal perforation is a serious complication necessitating immediate therapy. In a retrospective study we have evaluated the results in 13 children treated for esophageal perforation. Eleven of 13 perforations could be managed conservatively. In one child with extrapleural effusion, tube drainage was performed. The only death in this series occurred in a child who was brought for treatment after a 60-hour delay. Thoracotomy and multiple abscess drainage eventually proved unsuccessful. On the basis of our experience with children with esophageal perforation or with complications after esophageal atresia repair, we conclude that management of esophageal perforation in children differs substantially from therapy in adults and necessitates restrictive treatment guided by clinical symptoms.

A multistate Kalman filter for neonatal clotting time prediction and early detection of coagulation disturbances.

The multistate Kalman filter was applied to develop a heparin dose proposal system and to detect coagulation disturbances during neonatal extracorporeal membrane oxygenation (ECMO). A system containing this filter was based on the activated clotting time (ACT) values and the heparin doses administered every hour during ECMO. If the ACT value can be predicted accurately from the previous heparin dose, a heparin dose proposal can be given to achieve or maintain the required ACT level. The analysis was done on 6,356 ACT level measurements in 44 ECMO neonates. The multistate Kalman filter technique showed an unbiased prediction of ACT, with a standard deviation of 23 seconds. Two out of three cases of disseminated intravascular coagulation (DIC) were detected. ACT values were predicted sufficiently accurately by the multistate Kalman filter technique to justify a prospective study on the performance of the heparin dose proposal system and its ability to detect DIC.

Paraesophageal hernia: a major complication of Nissen's fundoplication.

Paraesophageal hernia was a major complication in a number of patients who were treated surgically for gastroesophageal reflux by fundoplication. This major complication seems to be predominant in the pediatric age group. The best surgical treatment for gastroesophageal reflux, whether a hiatus hernia is involved or not, is still uncertain. As with many other surgical problems where we must find a compromise, several surgical techniques are adopted. The choice of the surgical approach may depend upon the indications. As the indications for surgery are precise, the results must be reached with the utmost certainty, particularly hen complications already exist (esophagitis, stricture). The results of operative treatment of gastroesophageal reflux are in part, at least, influenced by the considerable tendency to spontaneous improvement, particularly in infants. In most cases, nonoperative treatment is initially undertaken if there are no prior complications. The number of children who are surgically treated depends to a great extent upon the accuracy of this conservative treatment.

Cardiac tamponade: a rare but life-threatening complication of central venous catheters in children.

The widespread use of central venous catheters in the treatment of pediatric patients has caused an increased incidence of complications. A rare, but potentially fatal complication occurs when the heart is perforated by the catheter tip causing a cardiac tamponade. This perforation of the heart generally is associated with the insertion procedure, but may also occur after some time because of displacement of the catheter tip. The authors present three cases in which the placement of a central venous catheter resulted in lethal cardiac tamponade. Proper positioning of the catheter tip in the superior vena cava and a high index of suspicion are essential in preventing this serious complication. Contrast-enhanced chest x-ray after insertion of the catheter must be performed to ascertain a correct position of the tip.

Perianal abscess and fistula-in-ano in infants.

PURPOSE: The aim of this study was to obtain insight into the short- and long-term results of treatment of perianal abscess and fistula-in-ano in infants. METHODS: This is a retrospective study of the records of patients treated over a 21-year period from January 1974 until December 1994 in a Pediatric Surgical Center. A long-term (1 to 24 year, mean 7.74 year) follow-up by questionnaire (response 81%) is also included. RESULTS: Drainage of a perianal abscess is followed in 35% of cases by a fistula. Fistulotomy or fistulectomy is followed in 13% of cases by a recurrence. There were two long-term recurrences that both healed spontaneously. The persisting scar sometimes gives problems with anal cleaning. All children aged 3 years and older were continent for feces. In two, there was soiling for some time. One had constipation and one was incontinent during the night. CONCLUSIONS: Simple drainage of a perianal abscess is followed frequently by a fistula. Fistulotomy or fistulectomy of a fistula-in-ano in infants has a reasonable chance of recurrence in the short term. Long-term recurrences are exceptional. There are no serious disabilities in the long run.

Chronic relapsing pancreatitis in childhood.

As a result of our experience and a review of the literature, early investigation by endoscopic retrograde cholangiopancreaticography (ERCP) and surgical intervention is recommended in chronic relapsing pancreatitis in childhood.

Quality of life after operatively corrected high anorectal malformation: a long-term follow-up study of patients aged 18 years and older.

Fifty-eight patients (median age, 26.0 years; range, 18.1 to 56.9 years) with an operatively corrected high anorectal malformation were evaluated by questionnaire. No patient had normal continence for feces; however, 84% had a socially acceptable defecation pattern. The quality of life (QOL) and general and mental health perception of these patients were evaluated. For social functioning and health perception, items from the medical outcome study (MOS) were used. QOL and health perception were compared with those of the general population. Most aspects of QOL (corrected for age and gender) and mental health did not differ from those of the general population. However, the patient population had lower educational and general health levels (P < .01). Twelve percent felt restricted socially by their handicap, and 24% never had a lasting relationship. Of the patients who had a lasting relationship, 43% noted that the handicap had been disturbing in the relationship. Associated anomalies had no influence on QOL and health perception. QOL, education level, and relationships were affected by fecal incontinence. It is possible that more appropriate psychosocial support, eg, addressing the implications of the handicap on everyday life, would have a positive influence.

Early closure of enterostomy after exteriorization of the small intestine for abdominal catastrophies.

Little has been written about the follow-up after temporary exteriorization of the small bowel for intraabdominal catastrophies in neonates and small infants. This report summarizes our results in 27 patients who had as a rule intestinal continuity restored electively within 4 weeks. There was a leakage rate of 10% and no mortality.

Gallbladder embedded in an accessory liver lobe in umbilical cord hernia.

Two newborns are described, both with a hernia of the umbilical cord, which contained the gallbladder embedded in an accessory lobe of the liver.

Surgical repair of an aortic coarctation in a patient after treatment with extracorporeal membrane oxygenation.

Extracorporeal membrane oxygenation (ECMO) is a life-saving treatment for neonates who have severe respiratory failure that does not respond to maximal conventional therapy. A consequence of venoarterial ECMO is the sacrifice of the right common carotid artery. Evaluation of the impact of a single carotid artery in babies treated with ECMO concerns mostly long-term neurodevelopmental outcome. The authors encountered a peculiar problem caused by a single carotid artery in a post-ECMO patient during the surgical correction of aortic coarctation with hypoplastic distal aortic arch. For patients with a confirmed cardiac malformation that necessitates future surgical repair and for whom ECMO support is required, reconstruction of the right common carotid artery should be considered. Veno-venous ECMO is an alternative solution if this approach is not contraindicated because of the patient's clinical condition. Patients with congenital diaphragmatic hernia have a higher incidence of cardiac malformations; therefore, careful cardiological attention is required. Anomalies masked by pulmonary hypertension also must be considered.

Surgical repair of congenital diaphragmatic hernia during extracorporeal membrane oxygenation: hemorrhagic complications and the effect of tranexamic acid.

Extracorporeal membrane oxygenation (ECMO) was incorporated in a strategy of delayed repair of congenital diaphragmatic hernia (CDH) and was used for preoperative stabilization in patients who were unresponsive to maximal conventional treatment. If ECMO was required for preoperative stabilization the diaphragmatic defect was repaired while the patient was on ECMO. In the early experience with this approach all patients suffered from bleeding complications. Therefore, we adopted the use of antifibrinolytic therapy with tranexamic acid (TEA) during and immediately after CDH repair on ECMO. The efficacy of TEA was studied in an unblinded study using historical controls by comparing the postoperative blood loss and the transfusion requirements of red blood cells (RBC) in patient groups treated without (n = 9) and with TEA (n = 10). Patients who received TEA had significantly less bleeding at the surgical site than patients not receiving TEA (57 v 390 mL, P = .005) and had significantly lower RBC transfusion requirements than patients not receiving TEA (1.13 v 2.95 mL/kg/h, P = .03). In the very first two patients of the TEA group we encountered fairly severe thrombotic complications. TEA may have contributed to those complications. Based on the authors' experience they conclude: (1) TEA is effective in reducing postoperative blood loss, hemorrhagic complications, and RBC transfusion requirements associated with CDH repair on ECMO. (2) TEA may be responsible for thrombotic complications. (3) The appropriate, empirically established, dosage and administration patterns of TEA for CDH repair during ECMO seem to be one bolus of 4 mg/kg TEA intravenously 30 minutes before the anticipated CDH repair and a continuous infusion of 1 mg/kg/h TEA during the 24 hours after CDH repair.

Atypical mycobacterial infection of the parotid gland.

A localized atypical mycobacterial infection of the major salivary gland is a rare disease. In this report the cases of three patients with this lesion are presented. The diagnosis was based on the clinical picture, skin testing with specific antigens, bacteriologic culture, and histopathologic findings. The patients were successfully treated by total parotidectomy with facial nerve preservation, which in our opinion is the therapy of choice in localized atypical mycobacterial infections.

Improving survival for patients with high-risk congenital diaphragmatic hernia by using extracorporeal membrane oxygenation.

The benefit of extracorporeal membrane oxygenation (ECMO) in cases of high-risk congenital diaphragmatic hernia (CDH) was studied by comparing pre-ECMO (1987-1990) and post-ECMO (1991-1994) 3-month survival statistics. Fifty-five CDH patients who presented in respiratory distress within 6 hours after birth were referred--18 in the pre-ECMO era and 37 in the ECMO era. During the entire study period (December 1987 through July 1994) the patients were treated by the same protocol of preoperative stabilization and delayed surgery; the only difference was the addition of ECMO beginning in January 1991. The patients were stratified based on the response to conventional treatment: 1, no response (irretrievable); 2, stable; 3, unstable. The 3-month survival rate for the unstable neonates (who could not be stabilized by conventional therapy) improved from 0% (0 of 9) in the pre-ECMO era to 61% (11 of 18) in the ECMO era (P = .004). This highly significant difference shows that ECMO is a very valuable addition to the management of high-risk CDH patients whose conditions remain unstable despite maximal conventional therapy.

Do we use the right entry criteria for extracorporeal membrane oxygenation in congenital diaphragmatic hernia?

In a retrospective review we analysed alveolar-arterial oxygen difference (AaDO2) as an entry criterion for extracorporeal membrane oxygenation (ECMO) in neonates with several forms of acute respiratory insufficiency. Although for meconium aspiration syndrome, respiratory distress syndrome, sepsis, and idiopathic pulmonary hypertension of the newborn we found values in accordance with the literature, patients with congenital diaphragmatic hernia (CDH) met 80% mortality criteria with significant lower AaDO2 values. Several patients died before ever reaching usual entry criteria for ECMO, because serious lung deterioration makes AaDO2 values unreliable. Awaiting classical ECMO entry criteria for patients with CDH may at least partially explain the lower survival rate for ECMO in CDH.

The midline cervical cleft.

The midline cervical cleft is a rare congenital anomaly of the ventral neck. With reference to two patients with a midline cervical cleft, we discuss the clinical picture, the embryology, and the surgical treatment.

Multidisciplinary behavioral treatment of defecation problems: a controlled study in children with anorectal malformations.

BACKGROUND/PURPOSE: The most frequent consequences of being born with an anorectal malformation (ARM) are problems with fecal continence and constipation, which can have various negative implications. In this prospective, controlled study the effect of multidisciplinary behavioral treatment dealing with these problems is evaluated. METHODS: The effect of multidisciplinary behavioral treatment was studied in 24 children (15 boys, 9 girls; mean age 5.8 years). Thirteen children were allocated to the treatment condition. The 11 children allocated to the waiting list control group also were treated after a waiting period of 6 months. Children underwent follow-up after treatment. RESULTS: Compared with a waiting list control group, the experimental treatment group scores significantly better on 2 important measures ("Templeton," "Percentage of feces in toilet"). Although young children had poorer scores than older children before treatment, no significant differences in the favorable outcome of treatment were found between both groups after treatment. No effect of type of ARM on treatment was found either. The results of multidisciplinary behavioral treatment remain stable over a mean follow-up period of 7 months. CONCLUSION: Multidisciplinary behavioral treatment is an important and valuable supplement to the standard medical treatment of children born with ARM suffering from chronic defecation problems.

Recirculation in double lumen catheter veno-venous extracorporeal membrane oxygenation measured by an ultrasound dilution technique.

Recirculation is a limiting factor for oxygen delivery in double lumen catheter veno-venous extracorporeal membrane oxygenation (DLVV-ECMO). This study compares three different methods for the determination of the recirculation fraction during double lumen catheter veno-venous ECMO at ECMO flow rates of 150, 125, 100, 75, and 50 ml/kg.min in nine lambs: (1) an ultrasound dilution method, in which the change in ultrasound velocity in blood after injection of a saline bolus as a marker is used for determination of recirculation; (2) an SvO2 method using real mixed venous blood oxygen saturation, the gold standard, for determination of recirculation fraction; and (3) the CVL method, in which oxygen saturation of a blood sample of the inferior vena cava is considered to represent mixed venous oxygen saturation. In all methods, the recirculation fraction increased with increasing ECMO flow rate. The correlation coefficient between the ultrasound dilution method and the SvO2 method was 0.68 (p < 0.01); mean difference was -2.4% (p = 0.6). Correlation coefficient between the ultrasound dilution method and the CVL method was 0.48 (p < 0.01); mean difference was -18.1% (p < 0.01). The correlation coefficient between the SvO2 method and the CVL method was 0.51 (p < 0.01); mean difference was -15.7% (p < 0.01). The ultrasound dilution method is a useful method for measurement of the recirculation fraction in DLVV-ECMO and is easier to use than the other methods.

Follow-up in neonatal extracorporeal membrane oxygenation (ECMO).

In 34 survivors of the first 43 ECMO patients from our institution before discharge to another hospital or home an EEG, BAER, Head Ultrasonography, cerebral CT scan, Dubowitz score and ophthalmological inspection were performed. At one year of age Mental Developmental Index of the Bayley scales, Motor Quotient as well as pulmonary and neurological status were assessed. In 29 patients follow-up took place in our hospital. In 17 of them (59%) all tests before discharge were normal, 2 patients (7%) showed an abnormal BAER, an additional 5 patients (17%) had abnormal EEG and 2 patients (7%) had abnormal HUS in combination with abnormal cerebral CT scan. In 19 patients (33%) the Dubowitz score was abnormal at discharge. At one year of age neurological status was normal in 25 (86%) patients, respiratory status was normal in 22 (76%) and Mental Development Index was > 80 in 23 of the patients (79%). A significant correlation between Mental Development Index and Motor Quotient was found r = 0.50, p = 0.0065. It is concluded that more than one abnormal neurophysiological test before discharge may identify patients with additional risks for adverse outcome and that the respiratory status influenced psychomotor development at one year of age.