Comparison of the airtraq laryngoscope to the direct laryngoscopy in the pediatric airway.

Direct laryngoscopy (DL) is the most commonly used technique for tracheal intubation, but there is ongoing interest in new devices that have high success rates and are easily learned. The pediatric Airtraq (AT) is a recently developed intubation device that allows visualization of the glottis and intubation of the trachea without alignment of the oral, pharyngeal and tracheal axes. We studied the efficacy of the AT compared to the DL for laryngoscopy of young children with normal airway anatomy. In this prospective study, 49 children (5 yr and younger) scheduled for elective surgery under general anesthesia were randomized into two groups: intubation using direct laryngoscopy (DL group) and laryngoscopy using the Airtraq (AT group). Time to best view, time to intubate, first attempt success rate (FASR), and percentage of glottic opening seen (percentage of glottis opening score) were recorded. Data are presented as median and interquartile range. Time to best view was five (4, 7) sec in DL and five (4, 7.5) sec in AT. Time to intubate was 18 (14.7, 21) sec in DL and 22.5 (19.5, 25.5) sec in AT (P = 0.002). FASR was 100% in the DL and 83% in the AT. The percentage of glottis opening score was 80% (range 60-100%) in the DL and 100% (range 100-100%) in the AT (P < 0.001). In young children with normal airway anatomy, the AT provides a better view of the glottis than the standard laryngoscope, but it takes longer to intubate the trachea and the FASR is lower.

Laerdal infant resuscitators are unreliable as free-flow oxygen delivery devices.

Laerdal Infant Resuscitators (Laerdal Medical Co., NY) are commonly used as free-flow oxygen delivery devices during neonatal resuscitation in situations where oxygen but not mechanical ventilation is desired. This study evaluates the performance of these resuscitators as free-flow oxygen devices. Efficiency was measured by comparing oxygen flow entering the resuscitator to oxygen flow delivered by the resuscitator. Clinical impact was assessed by measuring simulated patient fiO2. Three randomly selected resuscitator bags were tested for oxygen delivery efficiency by comparing oxygen inflow to outflow over an inflow range of 1 to 15 liters per minute (lpm). Measured outflow was 18-24% of inflow, demonstrating that as much as 82% of the oxygen flow escapes via the safety air inlet, safety blow-off valves, and other leaks. With the patient valve assembly removed, efficiency improved to 53-59%. Simulated fiO2 ranged from 0.23 to 0.68 at 5 lpm oxygen flow. We conclude that use of the Laerdal Infant Resuscitator for the delivery of free-flow oxygen, even with the valve assembly removed, generates highly variable patient fiO2. The use of self-inflating bags for delivery of oxygen without manual ventilation should be reconsidered.

Ruptured spleen in children--15-year evolution in therapeutic concepts.

This is a 15-year retrospective study of 64 pediatric surgical patients with traumatic rupture of the spleen from 1976 to 1990. The overall mortality was 14% (9/64). All non-survivors had severe multiple traumata and no fatalities were attributable to splenic injury. During the first 5 years of the study, the traditional surgical approach of immediate laparotomy and splenectomy was employed. During the next 5 years we practised laparotomy with subtotal splenectomy and repair. During the final 5 years conservative management with clinical and ultrasonographic monitoring became predominant (1 splenectomy, 4 repair, 23 conservative treatments). Among the 55 survivors, 11 had splenectomy, 14 had splenic repairs and 30 were treated non-operatively. All survivors had excellent outcomes and there was only one complication: a local abscess following splenic repair. Based on a very strict protocol in conservative management, the total amount of transfused blood could be reduced remarkably during the last period. Splenectomized patients received pneumococcal vaccine and prophylactic antibiotic coverage was prescribed for febrile episodes. None of the splenectomized patients experienced septic episodes or increased rates of infection. Based on our experience, ultrasonographically monitored conservative management is the treatment of choice in most patients with splenic injury in childhood.

Hemodynamic effects of peritoneal dialysis in three children following open heart surgery.

We studied the hemodynamic responses of peritoneal dialysis (PD) in three children following open heart surgery. Hemodynamic measurements were made prior to a dialysis run, following the instillation of dialysis solution (20 ml/kg), and immediately prior to and 5 min after drainage of the peritoneal cavity. The same protocol was repeated 48 h later. There was a significant increase in right atrial pressure (RAP) and mean pulmonary artery pressure upon instillation of the dialysate into the peritoneal cavity (p less than 0.01). However, cardiac index, mean arterial blood pressure (MAP), systemic (SVRI) and pulmonary vascular resistances (PVRI), left atrial pressure (LAP), and oxygen saturation did not change significantly. There were no significant differences between responses in the initial study and that performed 48 h later. PD is associated with modest right-sided hemodynamic changes which, in this small group of patients, did not compromise patient care.

Hemodynamic responses to PaCO2 in children after open heart surgery.

We studied the hemodynamic effects of acute alterations in PaCO2 in ten ventilator-dependent children after open heart surgery. Despite end-tidal CO2 monitoring, five children inadvertently developed PaCO2 greater than 50 torr during the study. Increasing and decreasing PaCO2 in these children resulted in significant parallel changes in cardiac index (CI), oxygen delivery, physiologic shunt, mean pulmonary pressure, and right ventricular stroke work index, and inverse changes in systemic vascular resistance index (p less than .01). No significant hemodynamic changes were observed with alterations in PaCO2 in children whose PaCO2 remained less than 50 torr. These findings are partly related to significantly larger reductions in PaCO2 which occurred in the hypercarbic children compared to the others (25 vs. 12 torr; p less than .001). Heart rate, mean arterial BP, and venous filling pressures did not change significantly in either group. We conclude that mean alterations in PaCO2 less than or equal to 12 torr (range 28 to 50) have no significant effect on CI in children after open heart surgery. However, moderate hypercarbia and its correction to a mean PaCO2 of 30 torr are associated with significant effects on central hemodynamics. Moreover, no significant changes in the commonly monitored physiologic variables were observed despite large variations in PaCO2.

Relationship between core/peripheral temperature gradient and central hemodynamics in children after open heart surgery.

Anterior thigh, pretibial and midfoot surface temperatures (MFT) were measured by an infrared thermometer in 17 children after open heart surgery. Core temperature was measured by pulmonary artery thermistor and cardiac index (CI) by thermodilution. No significant relationship existed between the previous hour's urinary output (ml/m2.h) and either systemic vascular resistance index (SVRI) and CI. MFT was inversely related to SVRI (r = -5.3; p less than .0001) but not to CI. The core/peripheral temperature gradient correlated directly with SVRI (r = .38, p less than .01) and inversely with CI (r = -.28, p less than .05). There was no improvement in any of the correlation coefficients when hemodynamic variables were tested against temperature gradients from core to thigh and thigh to foot. Although these relationships are statistically significant, we conclude that they are not strong enough to be of value in predicting central hemodynamic status in children after heart surgery.

[Clinical aspects and problems of pigeon breast and funnel chest]. / Klinik und Problematik der Kiel- und Trichterbrust.

Chest wall protrusion and depression deformities, also known as funnel chest and pigeon chest, are nosologically a uniform entity. Our own histopathological studies revealed secondary changes, found likewise in arthroses, scolioses, aseptic osteonecroses and inflammatory processes, as well as changes found in so-called primary collagenous diseases of unknown aetiology. Investigation of the collagen metabolism did not disclose differences from the normal II-type collagen either qualitatively or quantitatively. The aetiology of funnel chest and pigeon chest can be defined as follows: A hereditary disturbance of metabolism results in weakening of the wall of the parasternal cartilage, effecting a deformation secondary to mechanical strain by respiration and growth. Psychocosmetic reasons are recognised as indication for operation. In our opinion, the optimal age for operation is the second to the sixth year of life. During 20 years, 765 patients were operated on at our hospital without lethality. Postoperative complications were pneumothorax (4%), pneumonia (2%), after bleeding (2%) and disturbed wound healing (7%). Late results 5 years following surgery were excellent in 57%, good in 27%, satisfactory in 10% and unsatisfactory in 6% of the cases, thus adding up to 84% good results.

Innovative palliative surgical procedure for hypoplastic left-heart syndrome.

A novel surgical procedure was performed on a 2-day-old infant with hypoplastic left-heart syndrome. It consisted of partitioning the pulmonary trunk thereby creating two channels, one leading to the pulmonary arterial system and the other to the aorta, and atrial septectomy to relieve left atrial pressure and facilitate mixing of blood. The technique avoids the use of conduits.

Ventilation during laryngoscopy in chronic obstructive lung disease.

Many patients requiring direct examination of the upper airway and gastrointestinal tract under general anesthesia have chronic obstructive lung disease, yet virtually no work has been done to assess the adequacy of their ventilation during laryngoscopy and in the early postoperative period. This study demonstrates that, using the Carden tube, their blood gases are well maintained even when areas outside the endolarynx, such as the upper esophagus, are examined. The Carden tube is shown to be easy to insert and remove as well as permitting a superior view of the larynx. Also, this study pinpoints the period of maximum danger of respiratory failure as occurring postoperatively in the recovery room. This should be independent of the method of ventilation employed at surgery and indicates the need for cocainization of the vocal cords before extubation, as well as careful, early postoperative monitoring. The problems of ventilation during direct examination of the upper airway and gastrointestinal tract are discussed and alternative methods evaluated.

Mechanical ventilation during laryngeal surgery: an evaluation of the Carden tube.

The effectiveness and safety of the Carden tube-oxygen injector system for ventilation was studied in 18 high-risk patients with obstructive airways disease during microlaryngeal surgery. Blood gas studies during operation demonstrated a mean Pao2 of 65.6 kPa (493 torr) and a mean PaCO2 of 4.5 kPa (34 torr) during mechanical ventilation. No serious complications were noted during operation. Fifty per cent of the patients had postoperative hypercapnia and in two the trachea was re-intubated. Airway maintenance and ventilation are discussed in detail and it is concluded that the Carden tube-oxygen injector system is a safe and convenient method for ventilating the lungs of patients with pulmonary disease who require microlaryngeal surgery.

Relationships between nucleoside triphosphate pyrophosphohydrolase activity and inosine triphosphate accumulation in human erythrocytes.

The relationship between nucleoside triphosphate pyrophosphohydrolast (NTPH) (EC 3.6.1.19) activity in erythrocyte lysates and accumulation of radioactive inosine triphosphate (ITP) in human erythrocytes incubated in vitro with [14C]hypoxanthine, was studied in 93 humans. When ITP accumulation, expressed as percentage of total radioactive nucleotides, was plotted against NTPH specific activity, an inverse relationship was found to exist. A continous spectrum of NTPH specific activities and ITP accumulation values exists in the human population and the relationship between these two parameters follows the relationship of substrate concentration to enzyme activity predicted by Michaelis-Menten enzyme kinetics. One interpretation of these data is that the ITP concentration in human red blood cells is controlled by the degradation of ITP to IMP and pyrophosphate catalyzed by NTPH.