Resuscitation fluid use in Australian and New Zealand Intensive Care Units between 2007 and 2013

INTRODUCTION

Recent evidence indicates that the choice of intravenous fluids may affect outcomes in critically ill patients.

METHODS

We recorded the administration of resuscitation fluids in patients admitted to Australian and New Zealand adult intensive care units (ICUs) for a 24-h period at 6 time points between 2007 and 2013. Changes in patterns of fluid use over this period were determined using regression analyses.

RESULTS

Of the 2825 patients admitted to the 61 ICUs on the 6 study days, 754 (26.7%) patients received fluid resuscitation. Of those receiving fluid resuscitation, the proportion of patients receiving crystalloid significantly increased from 28.9% (41/142) in 2007 to 50.5% (48/95) in 2013 (adjusted odds ratio (OR) 2.93; 95% confidence intervals (CI) 1.35-6.33; p = 0.006); of these, the proportion of patients receiving buffered salt solutions significantly increased from 4.9% (7/142) in 2007 to 31.6% (30/95) in 2013 (OR 7.00; 95% CI 2.14-22.92; p = 0.001). The use of colloids significantly decreased from 59.9% (85/142) in 2007 to 42.1% (40/95) in 2013 (adjusted OR 0.34; 95% CI 0.16-0.74; p = 0.007) due to a significant decrease in the proportion of patients receiving gelatin; 28.9% (41/142) to 2.1% (2/95) (OR 0.10; 95% CI 0.03-0.29; p ≤ 0.001).

CONCLUSION

Fluid resuscitation practice in Australia and New Zealand adult ICUs has changed over the 6-year study period. Crystalloid use increased primarily due to an increase in the use of buffered salt solutions while overall the use of colloid has decreased.

Compliance with Processes of Care in Intensive Care Units in Australia and New Zealand – A Point Prevalence Study

There are indications that compliance with routine clinical practices in intensive care units (ICU) varies widely internationally, but it is currently unknown whether this is the case throughout Australia and New Zealand. A one-day point prevalence study measured the prevalence of routine care processes being delivered in Australian and New Zealand ICUs including the assessment and/or management of: nutrition, pain, sedation, weaning from mechanical ventilation, head of bed elevation, deep venous thrombosis prophylaxis, stress ulcer prophylaxis, blood glucose, pressure areas and bowel action. Using a sample of 50 adult ICUs, prevalence data were collected for 662 patients with a median age of 65 years and a median Acute Physiology and Chronic Health Evaluation II score of 18. Wide variations in compliance were evident in several care components including: assessment of nutritional goals (74%, interquartile range [IQR] 51 to 89%), pain score (35%, IQR 17 to 62%), sedation score (89%, IQR 50 to 100%); care of ventilated patients e.g. head of bed elevation >30 degrees (33%, IQR 7 to 62%) and setting weaning plans (50%, IQR 28 to 78%); pressure area risk assessment (78%, IQR 18 to 100%) and constipation management plan (43%, IQR 6 to 87%). Care components that were delivered more consistently included nutrition delivery (100%, IQR 100 to 100%), deep venous thrombosis (96%, IQR 89 to 100%) and stress ulcer (90%, IQR 78 to 100%) prophylaxis, and checking blood sugar levels (93%, IQR 88 to 100%). This point prevalence study demonstrated variability in the delivery of ‘routine’ cares in Australian and New Zealand ICUs. This may be driven in part by lack of consensus on what is best practice in intensive care units, prompting the need for further research in this area.

Quantitative analysis of magnetic resonance images and neurological outcome in encephalopathic neonates treated with whole-body hypothermia

OBJECTIVE

To evaluate whether quantitative measures from magnetic resonance imaging (MRI) performed in hypothermia-treated encephalopathic newborns can differentiate patients with unfavorable neurological outcome.

STUDY DESIGN

Retrospective analysis of clinical data and MRI studies was performed in 47 full-term infants treated with whole-body hypothermia for neonatal encephalopathy. Apparent diffusion coefficients (ADCs) and T1 and T2 intensity ratios were measured in the basal ganglia and thalamus on axial MRI images. Unfavorable outcome was defined as (1) death or severe neurological deficits at discharge and (2) death or cerebral palsy/severe motor deficit at follow-up through age 9 months. Differences between groups with favorable versus unfavorable neurological outcome at each time point were compared. Optimal cutoff values for significant MR variables were determined with receiver operating curve analyses. Sensitivity and specificity of these cutoff values for predicting unfavorable outcome were calculated and results were compared with qualitative MRI interpretation.

RESULT

Infants presented with a median pH of 6.86, base deficit of 20 and Apgar scores of 1, 3 and 4 at 1, 5 and 10 min, respectively. Severe encephalopathy was present in 38%. Unfavorable outcome was present in 9 patients at discharge and in 13 of 26 patients with available follow-up data through 9 months. ADC values and T1 ratios were not significantly different between groups at either time point. T2 ratios in both the basal ganglia and thalamus were significantly higher in patients with unfavorable outcome, both at discharge and in follow-up. T2 intensity ratio in the basal ganglia and thalamus remained significantly associated with death or severe neurological deficit at discharge, after controlling for covariates in logistic regression analysis. Sensitivity and specificity of T2 intensity ratio for predicting unfavorable outcome at discharge were comparable to qualitative grading of injury in the basal ganglia and thalamus by a neuroradiologist.

CONCLUSION

Increased T2 signal intensity in the basal ganglia or thalamus in patients with hypothermia-treated neonatal encephalopathy is associated with unfavorable neurological outcome at discharge and later with motor deficit/cerebral palsy. Quantitative methods to assess MRI evidence of brain injury are important for providing objective measures to predict outcome in this high-risk population.

Biologically-Inspired Patterned and Coated Adhesives for Medical Devices

The challenge of having a medical device robustly and reversibly adhere to a tissue in a minimally-invasive way during a clinical procedure is significant and has yet to be solved. Materials that could perform this adhesion would be valuable for use in a wide array of devices, including wired and wireless endoscopes for gastrointestinal interventions; cardiovascular devices such as mobile robots that transverse the heart surface or fixation devices for open heart surgery; and for adhering craniectomy devices to the skull during decompressive treatment. Fibrillar patterned adhesives inspired by the micro- and nano-scale structures on the feet of geckos have been widely studied and synthesized and have shown great potential for reversible adhesion in dry environments. Preliminary work has also been conducted to enhance the adhesion of these materials in wet conditions by coating them with polymers that include dopamine methacrylamide (DMA), a synthetic sticky polymer inspired by the material found naturally in the holdfasts of mussels. These coated materials demonstrated wet adhesion enhancement at the nano-scale, but not at the macro-scale and not when compared to unpatterned materials. In this work, we take previously-developed gecko-inspired patterned arrays of fibers with mushroom-shaped tips which have demonstrated enhanced adhesion with respect to unpatterned materials in dry conditions and coat them with these same synthetic mussel-inspired polymers to enhance adhesion in fully-submerged wet environments. DMA-containing polymers were synthesized through a multistep process and applied to an array of micro-scale polyurethane fibers by stamping. Material samples were tested in a custom-built adhesion measurement system in contact with a 6 mm glass hemisphere in both dry and wet conditions. Flat DMA-stamped samples demonstrated as much as 7 times enhancement over uncoated samples, while patterned, coated samples demonstrated as much as 23 times adhesion enhancement. The sample also maintained 65% of its adhesive ability over 100 test cycles. These materials are the first to demonstrate reversible fibrillar adhesion in wet conditions at the macro-scale with respect to both unpatterned and uncoated materials on non-flat surfaces using intermolecular forces instead of suction forces. Versatile reversible materials capable of adhering to non-flat surfaces in wet conditions should continue to be studied for their value for a wide array of medical device applications.

Prognosis of sub-types of cancer of unknown primary (CUP) compared to metastatic cancer

21010

Background: The aim is to study the clinical characteristics and outcomes of a complete cohort of presentations of Cancer of Unknown Primary (CUP) compared with patients presenting with metastatic cancer of known primary site. Methods: All persons diagnosed with cancer in New South Wales, Australia, from 1980 to 2004 were studied using a population based cancer registry. Patients classified as CUP were documented, compared to those with initial metastatic presentations of a known primary, for the same period. Results: There were 65,239 histologically or cytologically confirmed metastatic cancers presented. Of these 46,435 (77%) were metastatic with a known primary site and 13,280 (22%) were CUP. The median survival (ms) of all patients presenting with CUP was 3 months compared with 7 months for metastatic cancers of known primary site (p<0.0001). Patients with CUP with adenocarcinoma had significantly worse prognosis compared to metastatic adenocarcinoma of known primary site. However patients with squamous cell CUP had a significantly better outcome (ms 12 months) than metastatic squamous histology with a known primary site (ms 5 months, p<0.0001) with 31% of squamous cell CUP alive at 6 years. For those with CUP and adenocarcinoma the risk of dying was 80% greater compared to those with a known primary and adenocarcinoma (HR 1.8 95%CI 1.7–1.8). For those with CUP and squamous cell carcinoma the risk of dying was 50 % less (HR 0.49 95%CI 0.46–0.53). CUP with small cell, (HR 0.77 95%CI 0.71–0.85) and undifferentiated histology (HR 0.84, 95%CI 0.76–0.93) after controlling for sex and age, had a significantly better prognosis than other metastatic cancers. Germ cell CUP represented only 0.2% of all CUP presentations. Conclusions: CUP is a heterogeneous classification of cancer with a poorer prognosis overall when compared to metastatic cancer of known primary site especially if adenocarcinoma. However, squamous cell and small cell CUP had a better prognosis suggesting a need for specific and more focused treatment. Lack of trends for less CUP presentations compared to reducing metastatic cancer over this 24 year period suggests that CUP is in part a distinct clinico-pathological entity rather than a missed primary diagnosis.

No significant financial relationships to disclose.

Intravenous anesthetics

Intravenous anesthetics continue to be a mainstay in the modern anesthesiologist's armamentarium. In this review the authors will discuss new advancements in the use of propofol, as well as a greater understanding as to its mechanism of action. Further, we will discuss the use of target controlled infusion systems, touch upon the possible benefits of the ultra-short acting opioids, and consider the role of alpha-2 agonists as an adjunct to anesthetic management.

Neurodevelopmental outcome in ECMO vs near-miss ECMO patients at 5 years of age

The objective of this study was to compare the outcome of children at 5 years of age who were treated with extracorporeal membrane oxygenation (ECMO) and those who were critically ill but did not meet ECMO criteria, identified as near-miss ECMO. In one of the longest studies of its kind, we compared the neurodevelopmental outcome of 76 5-year-old ECMO-treated children with 20 5-year-old near-miss ECMO patients with similar primary diagnoses. The two groups were compared for demographic data, level of ventilatory support, and degree of hyperventilation. The comprehensive assessment protocol included an assessment of intelligence (IQ), attainment of preacademic and early academic skills, and parents' report of adaptive behavior. Both groups had similar demographic data and primary diagnosis. The near-miss ECMO patients required increased ventilatory support but not significantly more than the ECMO patients. The cognitive outcome was similar in both groups with mean estimated Full-Scale IQ in the normal range for near-miss and ECMO groups (89 and 97, respectively). Rates of severe mental handicap (FSIQ < 70) (near-miss = 11%, ECMO = 12%) and risk for school failure (near-miss = 38%, ECMO = 37%) were also similar. More parents of near-miss ECMO patients reported immature adaptive skills than did parents of ECMO patients, although the numbers were small in each group. Rates of parent-reported child behavior problems were similar in both groups. ECMO and near-miss ECMO patients have similar cognitive and adaptive outcomes at 5 years of age. A significant number in each group are at risk of school failure and should be closely followed up.

Context-sensitive half-time and anesthesia: how does theory match reality?

The pharmacokinetic model, which describes context-sensitive decrement times, has received validation through direct measurement. Further validation has come from the ability of targeted infusion schemes to obtain reliable and stable concentrations of a variety of intravenous drugs. A complete understanding of the concept will enable the appropriate selection of drugs and an appreciation of the strengths and limitations of current drug delivery systems.

Pattern of neuropsychological deficit at age five years following neonatal unilateral brain injury

The pattern of language deficit following left-hemisphere brain injury and visual/spatial deficit following right-hemisphere injury in an adult or older child is well recognized, but has been inconsistently reported following presumed neonatal brain injury. Our prospective study of 24 children at age 5 with documented neonatal unilateral brain injury lends support to the theory of hemisphere specialization at the time of birth. Twelve children who had unilateral left-hemisphere lesion were compared to 12 children with unilateral right-hemisphere lesion of similar timing and severity. Relative visual/spatial deficit following right-hemisphere lesion and receptive language deficit following left-hemisphere lesion were identified. Lateralized measures of grip strength, fine motor speed, and fine motor dexterity were not significantly different between the groups for either hand in this nonhemiparetic study sample. Only one child with a left-hemisphere lesion was left-handed, and only one child (right-lesion) had a hemiparesis.

Severity of brain injury following neonatal extracorporeal membrane oxygenation and outcome at age 5 years

Neurodevelopmental evaluation in childhood provides an opportunity to study complex neurological compensation following documented neonatal brain injury, and furnishes important clinical information which may have an impact on patient care. We studied 152 term children treated with extracorporeal membrane oxygenation (ECMO) as neonates and who received routine neonatal neuroimaging and comprehensive neurodevelopmental evaluation at age 5 years. The cohort was divided into four groups based on an independent neuroimaging score: No lesion, N=88; Mild lesion, N=38; Moderate lesion, N=12; and Severe lesion, N=14. Standardized testing at age 5 included complete neuropsychological assessment, neurological evaluation, and assessment of motor function. All testing was conducted without knowledge of the neuroimaging score. The occurrence of disability by severity of neuroimaging was: No lesion=10%; Mild=13%; Moderate=33%; Severe=57%. The relative risk within the ECMO population for disability at age 5 after moderate or severe neonatal lesion was 4.3 (CI=1.0 to 17.5) and 11.7 (CI=3.3 to 41.3), respectively. The remaining non-disabled children who had moderate to severe lesions functioned within normal limits. Severity of neonatal neuroimaging was inversely associated with IQ scores, pre-academic skills, and neuromotor function. The effect size was small but the rank order was predictable. Our data identify in 5-year-old children an impact of brain lesion severity demonstrated on routine neonatal neuroimaging. The results indicate potential compensation following moderate and severe lesions, and suggest a subtle but consistent influence of even mild neonatal brain injury.

Performance of computer-assisted continuous infusion at low concentrations of intravenous sedatives

We studied the performance of a target-controlled drug infusion device, computer-assisted continuous infusion (CACI). Forty-one volunteers received one of midazolam (n = 11), propofol (n = 10), thiopental (n = 10), or fentanyl (n = 10) in sedative concentrations. Concentrations were kept constant for 45-70 min at five sequential target concentrations in each subject. Twenty-six subjects had arterial sampling and 15 had venous sampling to determine drug concentrations. Median performance errors, median absolute performance error (MDAPE), wobble, divergence, and median absolute constancy error (MDACE), defined as error around mean actual concentration at each target, were calculated. CACI demonstrated significant performance errors, which were different among drugs. MDAPE (5%-95% confidence interval) ranged from 22.9% (12.1%-39.6%) for propofol to 82.2% (36.0%-183.0%) for midazolam. Although performance errors could be large, CACI was able to maintain a constant serum concentration over time very successfully. The MDACE ranged from 5.6% (3.9%-17.3%) for fentanyl to 11.2% (8.9%-20.4%) for propofol. Few differences occurred between arterial and venous sampling, although when they occurred, arterial samples indicated larger errors. It is concluded that CACI is very successful at maintaining constant serum concentrations of these drugs at sedative concentrations. Arterial sampling should be used when the performance characteristics of an infusion device are being tested. However, venous sampling may be adequate to determine serum concentrations when a pseudo-steady state has been achieved.

Neurobehavioral and psychosocial functioning of children with opsoclonus-myoclonus syndrome

Childhood opsoclonus-myoclonus syndrome (OMS) is a movement disorder which typically strikes children in the early preschool years, seriously affecting intellectual, social-emotional and general adaptive development. This series of 13 cases with well-documented neurological histories, aged 1.7 to 16.3 years, provides an initial systematic evaluation of these children's neuropsychological, psychosocial and adaptive status. As expected, children with OMS had significantly reduced intelligence and severe speech and motor output problems; however, most of them also demonstrated a range of preserved neurocognitive abilities and impressive goal-directedness and communicative effort. Psychosocial problems included mild behavioral impairment on the Achenbach Child Behavior Checklist, and severe adaptive limitations on the Vineland Adaptive Behavior Scales despite relatively strong social skills. Developmental factors and likelihood of subcortical localization are discussed, and practical guidelines are provided for behavioral and educational management of these children.

Neurodevelopmental status at age five years of neonates treated with extracorporeal membrane oxygenation

OBJECTIVE

To determine the neurodevelopmental status at age 5 years among children who received extracorporeal membrane oxygenation (ECMO) in the newborn period as a treatment for severe cardiorespiratory failure.

METHODS

We conducted a prospective cohort study of 103 five-year-old ECMO-treated children born between June 1984 and July 1988, and treated at our institution. Thirty-seven healthy control children were recruited locally. The assessment protocol included a complete neuropsychologic assessment, psychosocial assessment with parent questionnaires, a standard neurologic evaluation, assessment of gross motor and fine motor function, a medical history, and physical examination.

RESULTS

Major disability was present in 17 of the ECMO cohort. Eleven ECMO-treated children (11%) were mentally retarded, one of whom was profoundly impaired. Two additional children had severe learning disabilities. Cerebral palsy was diagnosed in 5 (5%) ECMO-treated children, but all cases were mild in nature and the patients were walking unaided. One child has paraplegia. The mean Full Scale, Verbal, and Performance IQs of the EMCO-treated children were within the normal range, but as a group were significantly lower than in control children (96 vs 115, p < 0.001). Children treated with ECMO had increased risk relative to the control children for academic difficulties at school age (49% VS 22%, P < 0.01) and a higher rate of behavioral problems reported by parents (42% vs 16%, p = 0.01).

CONCLUSIONS

The rate of major disability was comparable to that in other high-risk populations. The high rate of behavioral problems and increased risk of subsequent school failure among nonretarded ECMO-treated children supports the need for close follow-up of these children after hospital discharge.

Neonates treated with ECMO: predictive value of early CT and US neuroimaging findings on short-term neurodevelopmental outcome

PURPOSE

To determine if neuroimaging findings in infants who undergo extracorporeal membrane oxygenation (ECMO) are predictive of developmental outcome.

MATERIALS AND METHODS

At 1-2 years of age, 183 ECMO survivors (69 female, 114 male) underwent developmental examination. Neuroimaging studies obtained at time of ECMO were assigned a neuroimaging score. Neuroimaging findings were correlated with developmental outcome.

RESULTS

Eighty-five infants had neuroimaging abnormalities. Development was normal in 105 infants, suspect in 37, and delayed in 41. Mean neuroimaging scores were significantly worse in survivors with delayed development (P < or = .0001). The sensitivity and specificity of normal neuroimaging findings in prediction of normal outcome were 65% and 63%, respectively. Survivors with nonhemorrhagic abnormalities had a higher risk of delayed development than did those with isolated hemorrhagic abnormalities (39% vs 21%).

CONCLUSION

Although they cannot be used alone to predict outcome, early neuroimaging scores can be used to assign risk categories for developmental outcome.

Congenital diaphragmatic hernia: long-term outcome in neonates treated with extracorporeal membrane oxygenation

As more infants with congenital diaphragmatic hernia (CDH) survive with extracorporeal membrane oxygenation (ECMO), it seems prudent to detail the longterm outcome in these medically complex infants. Eighteen children with CDH-treated with postoperative ECMO were recruited for participation in this study. The mean duration of ECMO was 193 hours (range 82 to 493 hours), mean time to extubation after ECMO was 142 hours (range 34 to 312 hours), and median duration of hospitalization was 46 days (range 30 to 181 days). Of the 18 infants, 4 (22%) were discharged home requiring oxygen therapy. At follow-up the notable findings were a high incidence of gastroesophageal reflux and failure to thrive. At both 1 and 2 years of age, 50% of infants were at less than the 5th percentile for weight. At 1 and 2 years of age, 39% and 21%, respectively, were at less than the 5th percentile for weight/length ratio. A total of 16 children (89%) had clinical evidence of reflux, and 8 (44%) were discharged home on a regimen of nasogastric feedings. Reherniation occurred in 4 children (22%) and was more frequent when a patch was used. An electrocardiogram showed right ventricular hypertrophy in 6 (43%); oxygen saturation by pulse oximetry was > 95% in all children, and pulmonary artery pressure was estimated by Doppler echocardiography to be normal in 12 of 14 children examined. The neurodevelopmental outcome (Bayley Scales or Stanford-Binet scale) at 1 to 4 years of age was not dissimilar from that of other ECMO-treated children. Given the severity of illness in the neonatal period, the general health and development of children with CDH surviving after ECMO are good. Surprisingly few children have long-term respiratory complications related to pulmonary hypoplasia. Follow-up in the first few years should be aimed at aggressive nutritional intervention to prevent the growth failure that appears to be prevalent in these children.

Mortality and morbidity rates among lower birth weight infants (2000 to 2500 grams) treated with extracorporeal membrane oxygenation

To assess the validity of the currently accepted lower weight limit of 2 kg for treatment of neonates with extracorporeal membrane oxygenation (ECMO), we reviewed the outcome of lower birth weight (2.0 to 2.5 kg, n = 29) and higher birth weight (n = 235) for infants treated with venoarterial ECMO at our institution from 1984 through 1990. Newborn infants with congenital diaphragmatic hernia were not included. The mortality rate was significantly greater after venoarterial ECMO in lower than in higher birth weight infants (relative risk 3.45; confidence interval = (1.68, 5.79)). For infants with the diagnosis of respiratory distress syndrome, the mortality rate was 56% (5/9) for lower and 8% (2/25) for higher birth weight infants (p less than 0.01). The most frequent cause of death in lower birth weight infants was intracranial hemorrhage (7/10 deaths). The overall incidence of any neuroimaging abnormality was significantly greater for lower birth weight infants (p = 0.044), primarily because of the higher incidence of major intracranial hemorrhage. Finally, the risk of developmental delay (development quotient less than 70 at 1 to 2 years of age) among survivors available for follow-up was significantly higher among the lower than the higher birth weight infants. These outcome data suggest that further reduction of the current lower weight limit for ECMO should not become standard without prospective research or technologic advances.

Posterior fossa intracranial hemorrhage in infants treated with extracorporeal membrane oxygenation: sonographic findings

Posterior fossa hemorrhage was documented by autopsy in five infants who had been treated with extracorporeal membrane oxygenation over a 5-year-period. In all five cases, the diagnosis was made prospectively by cranial sonography. Sonographic findings were compared with those in a control group of 15 infants with normal posterior fossae at autopsy. The following sonographic abnormalities were exhibited in neonates with posterior fossae hemorrhage: loss of definition of the cerebellum and fourth ventricle on midline sagittal images, heterogeneous cerebellar parenchyma, focal hypoechoic lesions, ventricular dilatation, and tentorial abnormalities. Bright foci inferior to the third ventricle were seen in four neonates in the normal control group. These foci measured 5-10 mm in diameter. One cranial sonogram was falsely interpreted as showing a posterior fossa hemorrhage because of prominent echoes in the interpeduncular cistern. Infants treated with extracorporeal membrane oxygenation are at risk for developing posterior fossa hemorrhage. Awareness of sonographic signs and potential pitfalls in the interpretation of posterior fossa hemorrhage is important for early and accurate recognition of these unusual and sometimes treatable hemorrhages.

Light and the developing retina

Retinopathy of prematurity (ROP) has increased in the United States in the past decade. Its resurgence has been attributed to advances in medical care which have increased the survival of infants less than 1000 g. Retinal immaturity and exposure to supplementary oxygen are generally accepted as the principal factors associated with ROP, however precocious exposure of the immature retina to light may also contribute. The preterm infant is routinely exposed for the duration of hospital stay to bright continuous light at levels which produce retinal damage in animals. A recent study has provided evidence implicating light in ROP. Preterm infants for whom the light levels were reduced had a lower incidence of ROP, compared to a similar group of preterms exposed to standard levels of nursery light. Given the problems of a non-randomized design, the results must be considered preliminary; however the findings are substantiated by parallel results in both hospitals studied and by an effect of exposure to light within the treatment group. Speculations regarding the mechanisms of light as a contributor to ROP include: alterations of retinal metabolism, cellular damage by phototoxicity, and the generation of free radicals. Mechanisms of phototoxicity are compatible with theories of oxygen toxicity. Light may not be necessary for ROP to occur, but it may increase the risk.

CT of cerebrovascular injury after neonatal extracorporeal membrane oxygenation: implications for neurodevelopmental outcome

One hundred forty-six neonates treated with extracorporeal membrane oxygenation (ECMO) were evaluated with cranial sonography and CT at different times in the course of their disease. Cranial sonography was performed during treatment with ECMO, and CT was done 3-14 days after cessation of ECMO bypass. In 66 (45%), intracranial abnormalities were detected with either sonography or CT. Thirty neonates had hemorrhages only, 24 had nonhemorrhagic abnormalities, and 12 had combined lesions. CT provided additional information in 44 (67%) of the 66 neonates. Sonography was normal in 37 neonates, showed fewer lesions in 10 neonates, and was concordant with CT findings in 14 neonates. It cannot be established whether these lesions went undetected with sonography during ECMO, or occurred after cessation of ECMO bypass. Neurodevelopmental evaluation was performed in 71 of 90 survivors 1 year of age or older. Forty-three infants (61%) were normal; developmental delay was suspected in 12 (17%) and present in 16 (23%). The severity of intracranial abnormality as determined by a neuroimaging score correlated well with short-term developmental outcome. Mean neuroimaging scores were significantly higher, with increasing degree of neurodevelopmental delay (p less than .001 by Kruskal-Wallis rank order test). Although cranial sonography remains the primary technique for the detection of life-threatening hemorrhage during ECMO, cranial CT after ECMO is important in defining the total degree of intracranial injury present in these high-risk neonates.

Alfentanil and midazolam: new anesthetic drugs for continuous infusion and an automated method of administration

New drugs like alfentanil and midazolam have the primary advantage of metabolizing faster than existing compounds in their class. Because of shorter plasma half-lives, the drugs are well suited for continuous infusion. In our hands, CACI is a valuable clinical instrument and research tool. Although some anesthetic drugs can be given safely and effectively by bolus injection, whenever a titrated continuous infusion is appropriate (and physiologically closed-loop delivery is not possible), use of a CACI-type instrument should be the preferred method of administration. With the availability for continuous infusion of alfentanil and midazolam, with their highly desirable pharmacodynamic properties and relatively effervescent pharmacokinetics, we believe that computerized pharmacokinetic model-driven infusion devices will play a significant role in future anesthetic practice.

Morbidity for survivors of extracorporeal membrane oxygenation: neurodevelopmental outcome at 1 year of age

Extracorporeal membrane oxygenation is an important technology in the treatment of high-risk infants whose long-term outcome is being followed prospectively at our institution. The extracorporeal membrane oxygenation procedure allows temporary cardiopulmonary support for critically ill full-term neonates who are refractory to maximum ventilatory and medical management as a consequence of severe persistent pulmonary hypertension. The technique necessitates both the permanent ligation of the right common carotid artery and jugular vein and systemic heparinization. The survivors constitute a unique group of high-risk infants, from the standpoint of the hypoxic-ischemic insults preceding extracorporeal membrane oxygenation and the risks associated with the procedure. Our results indicate that most of our survivors are developing normally at 1 year. Major morbidity, in terms of either significant developmental delay (Bayley mental and motor indices less than 70) or significant neuromotor abnormality, occurred in only 10% of these infants. Poor outcome was associated with major intracranial hemorrhage and chronic lung disease. Ligation of the right carotid artery and jugular vein was not associated with a consistent lateralizing lesion. Long-term follow-up through school age is essential.

Retinopathy of prematurity: what causes it?

Retinopathy of prematurity continues to be a major cause of morbidity in surviving prematures despite attempts to regulate oxygen. Developing retinal vessels apparently can be disrupted by any of a considerable number of influences. By far the preeminent risk factor is extreme prematurity itself.

Do evoked potentials measure depth of anaesthesia?

Somatosensory evoked potentials have been suggested as a possible neurophysiological in of anaesthetic depth. In order to test the usefulness of this technique of monitoring, 8 patients were monitored during balanced anaesthesia. Following induction with a sleep dose of thiopentone, a neuromuscular blocking agent was used and the patients' lungs ventilated with N2O/O2(F1O2 = 0.3). This was supplemented with halothane or fentanyl. Somatosensory evoked potentials were recorded every 10 minutes during surgery, blood pressure and heart rate being recorded at the end of each evoked potential measurement. Induction of anaesthesia was associated with the reduction in SEP amplitude from 4.2 +/- 1.04 micro volts to 1.6 +/- 0.9 micro volts. There was an increase in latency from 19.2 +/- 1.3 msec to 20.0 +/- 1.3 msec to 20.0 +/- 1.5 msec. Recovery from anaesthesia was accompanied by an increase in SEP amplitude pre-induction values. There were no apparent correlations between the changes in evoked potential measures and changes in heart rate or blood pressure. Consistent change in somatosensory evoked potentials (prolonged latency, decreased amplitude) occurred with both narcotic and volatile anaesthetics. There was a recovery of evoked potentials at the end of anaesthesia. This is a promising technique, worthy of further evaluation.

Retinopathy of prematurity: progress report

For the time being, risk of ROP seems inexorably linked to survival of extremely low birth weight prematures, whose embryonic retinas develop in an abnormal and fluctuating environment. Incidence and severity may be reduced by stabilizing ventilation, oxygenation, and perfusion, moderating light exposure, and providing normal levels of vitamin E. Progression of stage 3 retinopathy may sometimes be arrested by cryotherapy. In the future, antioxidants or other pharmacologic agents may be developed to provide a greater margin of safety. In the meantime, the eyes of prematures must be examined and those with ROP will need specialized ophthalmologic care.

Cerebral hemodynamics in infants undergoing extracorporeal membrane oxygenation: further observations

Intracranial Doppler ultrasonographic examinations were performed on 64 infants treated with extracorporeal membrane oxygenation (ECMO). Serial studies were performed on the anterior cerebral artery in 55 infants before and during ECMO bypass, and on the middle cerebral arteries (MCAs) and internal carotid arteries (ICAs) on an additional nine infants. The onset of ECMO was associated with changes in character of pulsatile flow, direction of flow, and mean blood-flow velocity. Pulsatility decreased in all patients, and mean blood-flow velocity increased in 73% of patients (mean change from baseline, 87%). Despite retrograde flow in the right ICA in five of nine infants, antegrade flow to the right MCA was preserved in all cases. We found no correlation between alterations in mean blood-flow velocity and overall mortality, frequency of intracranial hemorrhage, and neuro-developmental outcome. These data suggest that wide variations in cerebral blood flow occur with ECMO therapy, and that these changes appear to be well tolerated.

Neurologic status in infants treated with extracorporeal membrane oxygenation: correlation of imaging findings with developmental outcome

A retrospective review was done of intracranial images obtained within the newborn period in 46 infants who had been treated with extracorporeal membrane oxygenation (ECMO). A neuroimaging score was determined on the basis of the extent and severity of findings on both ultrasound and computed tomographic scans. Presence of abnormality at neuroimaging and the neuroimaging score were correlated with the findings of neurodevelopmental evaluations (Bayley scales) performed in infants who were at a mean age of 11.8 months (range, 6-16 months). A significant inverse correlation was found between the neuroimaging score and mental and psychomotor development indexes of the Bayley scale (P less than .005). Mean neuroimaging scores in infants with normal development were significantly lower than those in infants with delayed development (P = .002). Although individual outcomes cannot be predicted with neuroimaging, the neuroimaging score can be a useful adjunct in assigning patients who survive with ECMO treatment to risk categories for developmental outcome.

Effect of bright light in the hospital nursery on the incidence of retinopathy of prematurity

The preterm infant is subjected to prolonged exposure to ambient nursery illumination at levels that have been found to produce retinal damage in animals. We prospectively investigated the effect of exposure to light in two intensive care nurseries by comparing the incidence of retinopathy of prematurity among 74 infants from the standard bright nursery environment (median light level, 60 foot-candles [ftc]) with the incidence among 154 infants of similar birth weight for whom the light levels were reduced (median, 25 ftc). There was a higher incidence of retinopathy of prematurity in the group of infants who had been exposed to the brighter nursery lights, particularly in those with birth weights below 1000 g (86 percent vs. 54 per cent, P less than 0.01 by chi-square test). We conclude that the high level of ambient illumination commonly found in the hospital nursery may be one factor contributing to retinopathy of prematurity and that safety standards with regard to current lighting practices should be reassessed.

Fetal exposure to narcotics: neonatal sleep as a measure of nervous system disturbance

Newborn infants, chronically exposed in utero to low doses of methadone with or without concomitant heroin, display more rapid eye movement sleep and less quiet sleep than control infants, while babies fetally exposed to both opiates and nonopiates have less organization of sleep states. Other perinatal factors, such as birth weight and gestational age, are related more to the amount of fetal drug exposure than to the type.

Prehepatic hyperalimentation

A technique for prehepatic infusion of parenteral nutrients is described. Portal vein hyperalimentation allows hepatic modification and control of the infused nutrients before delivery of these substances into the general circulation and theoretically should reduce the incidence of metabolic complications of hyperalimentation. The clinical experience with prehepatic infusions is reported and the metabolic investigations are described. Transumbilical catheters provided prehepatic delivery of parenteral nutrients for 1 month after esophagogastrectomy for esophageal malignancy without serious infection or portal vein thrombosis. Close surveillance of blood glucose and serum osmolarity demonstrated metabolic stability during the infusion period. Nitrogen balance studies showed better nitrogen economy than is achieved by infusion of similar solutions into the central systemic circulation. Indirect calorimetry indicated that the nitrogen used for production of energy was less than the amount supplied by prehepatic infusions. The same basic liver function abnormalities encountered with systemic infusion of hyperalimentation solutions were noted. The patients gained weight after esophagogastrectomy and did not experience the attrition from malnutrition which usually occurs in the first several months after esophageal resection.

A comparison of the bronchodilator effects of the same amounts of terbutaline aerosol given as a single or in divided doses

Inhalation of 0.5 mg of terbutaline, given as a single dose or as two immediately consecutive doses of 0.25 or four consecutive doses 0.125 mg, produced the same degree of effective bronchodilation in 12 asthmatic patients at all measured intervals from 30 seconds to four hours after administration. Each treatment regimen produced equivalent improvement in FVC, FEV1, MMEF, MVV, PEFR, V Max 50% VC and V Max 25% VC. The most sensitive indicators were MMEF and V Max 50% VC. No significant side effects were encountered with this dosage and route of administration. The clinical significance of this study is that in patients who are trained in the proper use of metered dose dispensers a single 0.5 mg inhalation may be sufficient to deliver the required dose to obtain an effective and safe therapeutic response.

Use of high dose corticosteroids in patients with inoperable brain tumours

Eleven patients with inoperable brain tumours were treated with high doses of corticosteroids (methylprednisolone 200-2000 mg/day) for up to 151 days (mean 55 days). Neurological improvement occurred in eight patients on high doses after deterioration on concentional doses (methylprednisolone 80-120 mg/day). In two patients steroids could be completely discontinued for several months. Serious adverse effects included sepsis in three patients and myopathy in tow. All three patients with sepsis also received chemotherapy. There were no deaths that could be attributed to steroids. The most likely effect of high dosage steroids is reduction of cerebral oedema. It is conceivable that in some instances high dose steroids may also result in tumour inhibition or oncolysis or both.

The bronchodilator effects of terbutaline: route of administration and patterns of response

The effectiveness and clinical indications of Terbutaline as a bronchodilator were analyzed by the subcutaneous, oral and aerosol route in 56 patients. A significant improvement in air flow rates both in major and smaller airways was achieved by all routes of administration. The inhalation route offered the fastest onset of action, maximal response and longest duration. Similar trends, but of decreased magnitude, were seen following the subcutaneous and oral routes. Overall analysis of results did not indicate a definite dose-response dependency within the aerosol and oral routes at the tested dosages, whereas the incidence of side effects was clearly dose-dependent. On this basis it is recommended that for maintenance therapy treatment should begin with oral Terbutaline 2.5 mg every 6-8 hours and this dose be adjusted according to the clinical response. For the treatment of acute bronchospasm 0.50 mg or 0.25 mg subcutaneously, or a dose as low as 0.375 mg by aerosol, would be highly effective within five minutes. A combination of oral and aerosol administration represents a highly effective synergistic combination for most clinical situations requiring maintenance therapy.

Hemodynamic changes associated with angina pectoris induced by maximal treadmill exercise: effect of sublingual isosorbide dinitrate on systolic time intervals

A technique for the study of patients with angina pectoris has been described, in which systolic time interval (STI) measurements are obtained at intervals after the onset of stress-induced angina. The technique is uniquely suited to the evaluation of anti-anginal drugs. Sublingual isosorbide dinitrate (SISD) was randomly alternated with a placebo (P) tablet in a double-blind study of 20 patients with stable angina pectoris. After SISD, compared to placebo, a highly significant shortening of Q-S2 and LVET occurred (p less than 0.001) which lasted throughout the entire 120 minute study period. The hemodynamic basis for these differences was felt to be improved myocardial contractility secondary to a reduction in systemic vascular resistance and reduced venous return induced by the SISD. A significant prolongation of PEP occurred at 60 minutes post-SISD (p less than 0.01). This was attributed to an increase in the gradient between LVEDP and aortic diastolic pressure resulting from reduced venous return after SISD. The PEP/LVET ratio was significantly increased up to 60 minutes after SISD (P less than 0.05). Heart rate was uniformly higher post-SISD, compared to post-placebo values; the differences were highly significant up to 60 minutes (P less than 0.001) and remained significant at 120 minutes (p less than 0.05). The time to angina was significantly longer (immediately post SISD, p less than 0.05; 30 min, p less than 0.001; 60 mins, p less than 0.05; 120 mins, p less than 0.05); and the work load greater, for 120 minutes following SISD: the increase in the latter was highly significant for 30 minutes after SISD (p less than 0.001) and remained significant up to 120 minutes (60 mins, p less than 0.05; 120 mins, p less than 0.05). These observations were attributed to an improvement in myocardial function due to the sublingual isosorbide dinitrate. A high degree of correlation was found to exist between heart rate and the STI. This correlation was negative for the QS2 interval (-0.996) and LVET (-0.993) and positive for PEP (+0.817) and the PEP/LVET ratio (+0.950).