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This article is intended to provide a review of the literature describing adverse occurrences affecting children in the intensive care unit. In addition, information related to the care of critically ill children is inferred from studies of adult or neonatal patients. Finally, areas in need of future investigation are suggested.

The medical management of the child with congenital cardiac disease prior to and following cardiac surgery has made a substantial contribution to the improved morbidity and mortality attributed to surgical advances. This paper provides a framework for understanding the problems that arise in the perioperative period and a systematic approach, by organ system, to monitoring and management of these problems. The discussion is intended to be of general application, focusing on initial stabilization following surgery and the cardiorespiratory, renal, metabolic, hematologic, and neurologic alterations that result from surgery with cardiopulmonary bypass. An approach for the management of the low output state is also provided. Little attempt has been made to focus on problems unique to a specific type of cardiac disease or certain operative approaches. Rather, it is the contention that an understanding of general principles and an appreciation of the common problems will provide adequate preparation for those responsible for the care of the child.

Although a considerable amount of information is available regarding the remodeling and growth of the pulmonary arterial circulation, relatively little is known regarding postnatal development of the pulmonary microcirculation. We hypothesized that the maximal velocity (Vmax) of pulmonary angiotensin-converting enzyme (ACE) activity, measured from indicator-dilution outflow curves using a synthetic substrate, 3H-labeled benzoyl-phenylalanyl-alanyl-proline (BPAP), is directly related to the capillary endothelial cell surface area in the lungs of developing lambs. Accordingly we measured apparent kinetics of pulmonary ACE activity in 22 anesthetized ventilated lambs (2-171 days old) and compared our functional assessment to simultaneous in vivo determinations of CO diffusing capacity (DLCO) and postmortem structural assessment of alveolar septal dimensions using stereology and electron microscopy. There was a progressive increase in Vmax of ACE in this age group, with little change in apparent affinity for BPAP. Similar functional manifestation of growth was noted by an age-dependent increase in DLCO. Neither Vmax nor DLCO was significantly affected by an increase in left atrial pressure to 19 Torr (via inflation of a balloon in the left atrium), suggesting little recruitment of vessels under conditions of the present protocol. A close correlation was observed when either Vmax for ACE activity or DLCO was plotted vs. capillary endothelial cell surface area. Double logarithmic transformation of capillary endothelial cell surface area, Vmax-ACE and DLCO vs. lung volume revealed power functions with slopes all greater than that predicted from isotropic growth, suggesting selective differential postnatal development of the endothelium of the alveolar septum in lambs from 2-171 days of age.

We studied the response of O2 consumption, systemic O2 transport, arterial blood lactate concentration, base deficit, and respiratory exchange ratio (CO2 production/O2 consumption) to graded alveolar hypoxia (fractional concentration of inspired oxygen 0.21, 0.16, 0.12, and 0.08) in seven intact, conscious chronically catheterized lambs at less than 1 wk after birth, at 25-40 days and at greater than 40 days. To test whether there was an age related difference in the metabolic response to a decline in O2 transport due to hypoxemia, we related the changes in blood lactate and base deficit to the systemic O2 transport and to the fractional change in O2 consumption. Systemic O2 transport and O2 consumption decreased with severe hypoxemia, while lactate concentration and respiratory exchange ratio increased in all age groups. The changes in base deficit were not significant. When the hypoxemia-induced reduction in O2 consumption was less than 15% of the baseline value (at fractional concentration of inspired oxygen 0.21) there was no elevation in lactate concentration; however, when O2 consumption was reduced by more than 15%, lactate concentration consistently increased by more than 1 mmol/liter. There were no apparent differences amongst the age groups in this response. Therefore, the newborn lamb does show metabolic consequences of a fall in O2 consumption with hypoxemia which is similar to the older sheep, however, there is a "buffer zone" in which O2 consumption may decrease before evidence of tissue hypoxia can be found. The mechanism by which O2 consumption can decrease without accumulation of lactate remains speculative.

In both new and old tendon injuries, errors and hidden dangers exist that may lead to later complications. These arise at all four phases of primary repair or secondary reconstruction, namely preoperative assessment, exposure and evaluation, repair or reconstruction, and, finally, postoperative care. Often, the resulting complications are the same following tendon suture or tendon graft, the most common being adhesion with joint contracture. The list of complications also includes rupture, bowstringing, skin necrosis, infection, recurvatum, the lumbrical plus finger, and the quadriga syndrome.

In choosing which flap to employ for a particular defect, the surgeon should think again about areas of skin availability. Where insufficient skin is present for a flap design that permits no skin graft, such as a rotation or a rhomboid flap, then a simple transposition flap with a graft on the secondary defect may serve admirably. In planning a local flap, the inexperienced surgeon should always think of an elegant escape should this plan not work--the experienced one always does. In raising the flap, the surgeon should remain aware that he is challenging its blood supply and thereby rendering it more vulnerable to injury; he should take care that he not inflict that injury during dissection. The skin hook and the knife are more precise and less damaging than the forceps and the scissors and should be used in preference. By rendering tissues tense with judicious hook traction, natural planes are revealed. By pursuing such planes much less trauma is inflicted than in creating planes where none exist. The design and execution of a local flap is an intellectual and elegant pursuit worthy of any surgeon. If the surgeon, in turn, is worthy, he or she will appreciate that fact and gain much satisfaction from the practice.

A wide variety of artifacts may be found when monitoring the ECG in a neonatal intensive care unit. Many of the artifacts resemble arrhythmias, and unless they are recognized as artifacts they may lead to serious errors of diagnosis and therapy. Many of the artifacts are caused by patient movement such as seizures, tremulousness, or hiccups. Others may be introduced by the monitor itself or be caused by electrical equipment in the vicinity. A group of ECG tracings is presented to illustrate the various artifacts encountered. Features that distinguish the artifacts from the arrhythmias they mimic are described, as are suggestions for elimination of the artifacts.

Angiotensin-converting enzyme (ACE) activity of the cerebral microcirculation of anesthetized dogs was measured from cerebral venous outflow curves after bolus injection of a synthetic ACE substrate, [3H]benzoyl-phenylalanyl-alanylproline ([3H]BPAP), into a common carotid artery. Cerebral BPAP metabolism was quantified by measuring the concentration of [3H]benzoyl-phenylalanine (the product of BPAP hydrolysis by ACE) in blood samples from the sagittal sinus after occlusion of the lateral sinuses with bone wax. Instantaneous BPAP metabolism in each sample increased as a function of time after injection, suggestive of perfusion heterogeneity, and averaged 59 +/- 4% (n = 8) over a single pass during normoxia and normocapnia. The ratio of Vmax (the maximal rate of cerebral BPAP metabolism) to Km (the concentration at Vmax/2), was calculated from instantaneous outflow curves using a model based on first-order kinetics. Increases in cerebral blood flow during either hypoxia or hypercapnia significantly reduced BPAP metabolism to 33 +/- 3 (n = 7) and 24 +/- 3% (n = 5), respectively; however, Vmax/Km of ACE activity (0.19 +/- 0.03 ml/s) was not affected by either condition. The lack of change in apparent kinetics of ACE activity (i.e., in Vmax/Km) during hypoxia or hypercapnia suggests that recruitment of cerebral capillaries was not a quantitatively significant factor in controlling BPAP metabolism with this degree of either hypoxia or hypercapnia.

Twelve second-toe transfers have been performed to substitute for thumbs congenitally deficient through constriction ring syndrome, symbrachydactyly, and true transverse arrest. The children were on average 3 years of age, and the youngest was undertaken at 10 months. Anatomic variations were the rule in the six cases of transverse absence and the three cases of symbrachydactyly, requiring nerves, tendons, and vessels in the toe be connected to whatever appropriate structure could be located. All transfers survived, and only one required exploration. Sensation appeared good in the 11 seen in later review, but interphalangeal motion was achieved in only 3. However, good use was made of the digit by all except one patient, an early patient in whom there was not an adequate skeleton on which to base the transfer. This small series suggests that in appropriate cases toe transfer can be undertaken early for congenital deficiency with little fear of encountering microsurgical problems unique to the infant.

One hundred cases of osteosynthesis done by the use of intraosseous wiring are presented. Two techniques of wiring are described, one used in transverse fractures and arthrodeses in which an additional Kirschner wire is employed, the other in which No. 0 monofilament wire can be placed perpendicular to the line of osteosynthesis. Forty-seven fractures were treated and there was union in all cases; 53 arthrodeses were performed, with failure in five, due, it is believed, to a failure to observe the essential elements of the technique, namely the need to obtain congruous bone ends and to maintain all internal fixation until there is clinical evidence of union. Overall, 83.2% of the maximum attainable total active range of motion was achieved in the 100 cases.

The biology, management, and results of primary repair and secondary reconstruction are reviewed. Repair of the tendon sheath and controlled mobilization appear to improve the results of both groups.

It has been well documented that the lungs are able to remove or metabolize several vasoactive substances passing through the pulmonary circulation. One such function, the conversion of angiotensin I to angiotensin II and hydrolysis of bradykinin to inactive peptide fragments is performed by angiotensin-converting enzyme (ACE). Although a precise role of these functions for systemic vasoregulation has not been defined, measurement of pulmonary metabolic capacity has the potential for providing substantial information about the integrity and physiology of the pulmonary microcirculation. Studies are described using 3H-benzoyl-phenylalanyl-alanyl-proline (a synthetic substrate for pulmonary ACE) in developing conscious lambs and older sheep. Outflow curves from indicator dilution measurements contain information regarding apparent kinetics of ACE activity. Using a nonlinear model for saturable pulmonary metabolic functions, the derived data demonstrate a) a marked increase in Vmax, the apparent maximal velocity of ACE, with age; and b) no significant change with age in apparent Km, the concentration at which the velocity of ACE is one-half Vmax. This approach has the potential for providing a biochemical tool for examining postnatal growth of the pulmonary microcirculation as well as functional integrity of the pulmonary endothelium during a variety of conditions.

To assess the change in venous admixture during breathing of 100 per cent oxygen (FIO2 1.0), shunt fraction (Qs/Qt) was calculated at a maintenance FIO2 (FIO2m:0.27--0.70) and at FIO2 1.0 in 40 studies of 34 patients with acute respiratory failure. At FIO2 1.0 Qs/Qt increased in 26 studies, but did not increase in 14 studies. Patients in whom Qs/Qt increased during breathing of oxygen and mild respiratory failure, as indicated by low Qs/Qt values at FI02m and a low incidence of diffuse parenchymal infiltrates on chest roentgenograms. All patients who had recently had cardiovascular surgical procedures were in this group. Respiratory failure was more severe in those in whom Qs/Qt decreased with oxygen, as indicated by high Qs/Qt values at FIO2m, evidence of diffuse pulmonary disease by roentgenography, and signs of adult respiratory distress syndrome. The authors conclude that changes in Qs/Qt in response to FIO2 1.0 in acute respiratory failure are related to the severity of respiratory insufficiency.

Evidence now exists that synovial fluid is a significant nutrient for tendon healing and that reconstruction of the sheath improves results following tendon grafts. Sheath closure is recommended after both primary repair and secondary reconstruction. Techniques have been developed to best effect this closure, either with available tissue or with sheath grafts transferred from elsewhere.

We measured cardiac output and its distribution (microspheres), blood gases and pH, heart rate, and pulmonary and aortic pressures in three groups of 1- to 3-day-old lambs. Group I consisted of six animals who had these measurements made during both control (normoxemic) and hypoxemic (PaO2 25 +/- 3 mm Hg) periods. Hypoxemia increased the pulmonary artery pressure 70% (p less than 0.01). This elevation in pulmonary arterial pressure lasted as long as the animals were hypoxemic (90 min). Hypoxemia had no effect on cardiac output, mean systemic arterial pressure, heart rate, or the rate-pressure product of the left ventricle. Blood flow to the heart increased an average of 228% (p less than 0.05); flow to the brain increased 233% (p less than 0.05); flow to the skin decreased 35% (p less than 0.05) after 60 and 90 min of hypoxemia. Blood flow to the remaining organs was uneffected by hypoxemia. Group II consisted of four animals who were given 1, 5, and 10 mg/kg/h of tolazoline (Priscoline) intravenously while normoxemic. There was no effect on the pulmonary arterial pressures or blood gases and pH. Tolazoline (5 and 10 mg/kg/h) reduced systemic arterial pressures an average of 22% (p less than 0.05). Tolazoline (1 mg/kg/h) reduced blood flow to the spleen 48% and that to the brain by 20% and increased flow to the body 32% (p less than 0.05). Five mg/kg/h of tolazoline decreased renal and brain blood flow 35 and 20%, respectively (p less than 0.05) while that to the body and liver increased 26 and 48% (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Stereologic methods were used to study lung development in sheep from 2 to 171 days of age. Most growth occurs within the first 2 months when there is a threefold increase in lung volume, but allometric relationships show that this increase does not keep pace with body weight. Alveolar and capillary surface areas increase as lung volume to a power only slightly larger than 1, suggesting a modest increase in complexity; this is confirmed by only a two- to threefold increase in total alveolar number. Allometric power functions are essentially unchanged even during the first 30 days so that throughout development, the surface for gas exchange is added at a fairly constant rate. A slight increase in septal volume during the first 30 days is probably due to relative increase in capillary luminal volume through a progressive distension of capillaries. The results suggest that the active newborn lamb requires an alveolar lung, but in the postnatal period functional needs increase only moderately. In contrast, other mammals, such as the rat, are helpless as newborns and have a primitive saccular lung that must undergo considerable morphogenesis to meet the demands of the active adult.

Defining replantation as the restoration of a completely amputated part as opposed to simply restoring circulation to an incompletely severed part, the results of replantation of 86 completely amputated parts in 71 patients performed from January, 1970, to December, 1975, were studied. Twenty-eight, or 32.5 percent, were the result of sharp severances of the part; localized crushing accounted for 56, or 65.1 percent. Two were classified as degloving injuries. Twelve amputations were transmetacarpal, six were at the metacarpophalangeal joints, 14 through the proximal phalanx, 15 at the proximal interphalangeal joint, 21 in the middle phalanx, 13 at the distal interphalangeal joint, and five through the distal phalanx. The technique consisted of bone shortening and fixation and repair of all tendons and nerves if possible. Veins are repaired first, at least two for each artery, and heparinized saline and lidocaine are used locally. Irrigation of the vessels is not done, but an intravenous bolus of 3,000 U. of heparin is given when the anastomoses are completed. Aspirin and low molecular weight dextran are given for 3 to 7 days. For the more distal replantation, heparin may be used. Antibiotics are given. In the total series of 86 completely amputated hand units, 52 were unsuccessful, primarly due to vascular thrombosis and usually on the venous side. In the year 1975 a success rate of 69.2 percent was achieved, whereas in the last 50 replantations, done between Jan. 1, 1976, and Oct. 15, 1976, the success rate was 90 percent. Results improved with more experience in the technique and with more careful selection of patients.