Jejunal feeding in the absence of reflux increases nasogastric output in critically ill trauma patients

Nasojejunal feeding of trauma patients is becoming a common practice. Aspiration rate comparisons between jejunal versus gastric-fed patients have been shown to be equal. We performed a retrospective evaluation of gastric output in 51 trauma patients who tolerated initiation and advancement of nasojejunal feedings. Gastric output was measured in the absence of reflux of feeds. Gastric output was compared over a 24-hour interval before initiation of feeds and after advancement to nutritionally complete levels. The increase in gastric output was found to be significant [301.9 +/- 19.8 mL/day before feeds, 587.8 +/- 47.1 mL/day (P = 0.01) after advancement of feeds]. The overall documented pulmonary aspiration rate in these patients was 5.9 per cent. Because of this significant increase in gastric output, nasogastric residual check should be performed routinely in patients receiving nasojejunal feeding.     

Endocrine disorders in critically ill children

Endocrine disorders in critically ill infants and children can be the manifestation of an existing but previously unrecognized condition, or hormonal derangements precipitated by deleterious effects on endocrine function of a critical illness or its prescribed therapy. To achieve successful resolution of these crises, a general understanding of various endocrine dysfunctions, clinical symptomatology, diagnosis, and medical and nursing management is essential.     

Acquired carnitine abnormalities in critically ill children

In order to characterize the role of carnitine during metabolic stress, we prospectively determined carnitine profiles in plasma and urine on admission, days 2, 5, 10 and 15, among 28 critically ill children free of any known conditions associated with secondary carnitine deficiency. More than 25% of plasma and 50% of urinary carnitine measurements were abnormal; 96% (27/28) of patients displayed on at least one occasion an abnormal [< -2 SD or > +2 SD] carnitine value in plasma. Three children had extremely low [< 10 micromol/l] free carnitine (FC) levels in plasma. Plasma esterified and FC levels on admission were not related to the risk of mortality [PRISM score], to muscle lysis [CK values], and to the caloric intake. Levels of FC and esterified carnitine in plasma were unrelated to those measured in urine. Conclusion: Abnormal plasma and urine carnitine measurements are frequently found in critically ill children; the biological significance of these perturbations remains unclear. Caution must be exercised before concluding that an abnormal carnitine value is indicative of an underlying hereditary metabolic disorder in this population.     

Ionized magnesium concentrations in critically ill children

OBJECTIVE: To test the hypothesis that many critically ill children exhibit ionized hypomagnesemia despite having normal total magnesium (TMg) concentrations. DESIGN: A prospective, observational study with convenience sampling. SETTING: Pediatric and cardiovascular intensive care units of a large children's hospital. PATIENTS: Patients aged 1 day to 21 yrs admitted from January 1 to October 31, 1996. Patients with chronic renal failure or weight <3 kg were excluded. A group of healthy children involved in a school-based nutritional assessment study were also studied. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Sixty-seven patients (5.4+/-5.7 [SD] yrs) and 24 healthy children (10.84+/-0.93 yrs, p< .001) were studied. Plasma was assayed for ionized magnesium (IMg) using a blood analyzer. Forty (59%)/67 critically ill subjects had IMg concentrations <0.40 mmol/L, the lowest published normal value and the lowest value observed in our group of healthy children. Of these, 24 (60%)/40 had normal TMg concentrations. IMg was significantly (p=.00) lower in critically ill subjects than in the group of healthy children (0.37+/-0.10 mmol/L vs. 0.46+/-0.03 mmol/L). IMg did not correlate strongly with ionized calcium (r2=0.49), albumin (r2=0.09), or pH (r2=0.18). CONCLUSION: Many critically ill children exhibit ionized hypomagnesemia with normal TMg concentrations. These children would not be recognized as magnesium-deficient based on routine TMg testing. Critically ill children exhibited significantly lower concentrations of IMg than a group of healthy children.     

Femoral vascular catheterization in critically ill infants and children

The success rate and complications from femoral arterial and venous catheterization in infants and children in a university affiliate pediatric intensive care unit were determined prospectively over a 2-year period. We also performed a meta-analysis from published literature to determine the combined estimates of noninfectious and infectious complications (with 95% confidence limits) using the inverse variance-weighted method. Success rates were 94.5% and 94.4% for femoral arterial (n=110) and venous (n=89) catheterizations, respectively, and were related to operator expertise, age, and hemodynamic status. Median age was 2.4 years and 1.1 year for arterial and venous catheterizations, respectively. Immediate complications were hematoma (10.9% arterial, 16.8% venous) and minor bleeding (13.6% arterial, 13.5% venous). Decreased pulses occurred with 7.7% of arterial catheterizations, and lower limb swelling occurred in 9.5% of venous catheterizations. Vascular complications occurred only in infants and resolved within 7-14 days. Catheter-related infections occurred in 1.9% of arterial and 3.6% of venous catheterizations. The mean duration of catheterization was 5.3 days and 6.3 days with femoral arterial and venous catheterizations, respectively. Meta-analysis of published studies shows that the estimates for noninfectious complications were 5.0%, 10.1%, 1.1%, and 1.8% for femoral arterial, femoral venous, axillary arterial, and nonfemoral venous catheters, respectively. The estimates for catheter-related infection were 2.5%, 3.7%, and 3.0% for femoral arterial, femoral venous, and nonfemoral venous catheters, respectively. The meta-analytic estimates for complication rates from published literature are not significantly different from the rates observed in our study. Femoral arterial and venous catheterization in infants and children are safe with an expected high success rate and acceptably low complication rates.     

Anthropometric nutritional assessment of critically ill hospitalized children

In a prospective study, the nutritional status was evaluated in 46 consecutive admissions to a Pediatric Intensive Care Unit, using anthropometric parameters. About 65% of the patients presented malnutrition on admission, with predominance of the chronic form. The mortality rate was greater in the malnourished (20 versus 12.5%) and chronic malnutrition was associated with a higher incidence of infection (42%). There was a fall in channel of percentile for weight-for-height in 36% of the patients evaluated at the final follow up. These results suggest that a significant number of patients are at nutritional risk at the time of hospital admission, and there is an association between nutritional status and hospital course. The anthropometric nutritional evaluation is a simple an reproducible method, and a valuable parameter for an objective nutritional assessment of the critically ill child. Therefore, it should be performed on admission and follow up of hospitalized children.     

Multiplane transesophageal echocardiographic doppler imaging accurately determines cardiac output measurements in critically ill patients

OBJECTIVES: To compare cardiac output and stroke volume measured by multiplane transesophageal Doppler echocardiography with that measured by the thermodilution technique. DESIGN: Prospective direct comparison of paired measurements by both techniques in each patient. SETTING: Cardiac surgery and myocardial infarction intensive care units. PATIENTS: Twenty-nine patients, mean age (+/- SD) 67 +/- 8 years. Nineteen had undergone open heart surgery and 10 had suffered acute myocardial infarction. METHODS: Cardiac output and stroke volume were measured simultaneously by the thermodilution technique and multiplane transesophageal Doppler echocardiography via the transgastric view (119 +/- 8 degrees) with the sample volume positioned at the level of the left ventricular outflow tract. RESULTS: Stroke volume and cardiac output measurements were obtained in 29 of 33 patients (88%). Mean values were 50 +/- 13 mL and 4.8 +/- 1.3 L/min by Doppler and 51 +/- 14 mL and 4.9 +/- 1.4 L/min by thermodilution (r = 0.90, r = 0.91, p < 0.001). The mean differences in values obtained with the two techniques were 1 +/- 6 mL (2 +/- 12%) and 0.1 +/- 0.7 L/min (2 +/- 12%). CONCLUSIONS: Multiplane transesophageal echocardiography enhances the ability to estimate accurately cardiac output and stroke volume by providing new access to left ventricular outflow tract in critically ill patients.     

Low-dose theophylline modulates T-lymphocyte activation in allergen-challenged asthmatics

Theophylline has been shown by several investigators to attenuate the late asthmatic response (LAR) to inhaled allergen, suggesting that it has anti-inflammatory or immunomodulatory properties. We have, therefore, undertaken a double-blind, placebo-controlled study to examine the effects of low-dose theophylline on bronchoalveolar lavage (BAL) and blood T-lymphocyte profile and activation in asthmatics following antigen challenge and the development of a LAR. Peripheral blood and BAL samples were obtained from 17 subjects with mild atopic asthma before and after 6 weeks of treatment with either oral theophylline or placebo. The mean serum theophylline concentration achieved was 6.6 micrograms.mL-1, which is below the currently accepted therapeutic range. Following theophylline therapy, there was a significant decrease in the number of BAL lymphocytes compared to placebo. On flow cytometric analysis of BAL cells, a significant loss of CD3+ T-lymphocytes, comprising both CD4+ and CD8+ subsets, was demonstrated. Moreover, there was a decrease in the number of BAL CD4+ T-cells expressing the activation marker very late activation antigen-1 (VLA-1), and an apparent reduction in human leucocyte antigen-DR (HLA-DR). Correspondingly, this was accompanied in the blood by an elevation in the proportion of activated CD4+ T-lymphocytes, in particular those expressing HLA-DR. These findings provide further evidence that theophylline has an anti-inflammatory action in asthma.     

Usefulness of gastric intramucosal pH for monitoring hemodynamic complications in critically ill children

OBJECTIVE: To assess the efficacy of gastric intramucosal pH for the evaluation of tissue perfusion and prediction of hemodynamic complications in critically ill children. DESIGN: Open prospective study without controls. SETTING: Pediatric intensive care unit (ICU) of a tertiary care university pediatric hospital. PATIENTS: Thirty critically ill children (16 boys and 14 girls), age range: 3 months-12 years. MEASUREMENTS AND RESULTS: A tonometry catheter was placed in the stomach of all patients on admission to the pediatric ICU. Simultaneous tonometry and arterial gas measurements were made on admittance and every 6-12 h throughout the study; a total of 202 measurements were made. The catheter was removed after extubation and/or when the patient was hemodynamically stable. Intramucosal pH was calculated using the Henderson-Hasselbalch equation based on the pCO2 of the tonometer and arterial bicarbonate. Intramucosal pH values between 7.30 and 7.45 were considered to be normal. The patient's condition was analyzed using the Pediatric Risk Mortality Score (PRISM). The relations between intramucosal pH and the presence of major hemodynamic complications (cardiopulmonary arrest, shock), minor hemodynamic complications (hypotension, hypovolemia or arrhythmia), death, PRISM score and the duration of the stay in the pediatric ICU were analyzed. Intramucosal pH on admission was 7.48 +/- 0.15 on average (range 7.04-7.68). Five patients (16%) had an intramucosal pH lower than 7.30 on admission; these patients did not have a higher incidence of hemodynamic complications. The 16 patients (53%) who had an intramucosal pH of less than 7.30 at some time during the course of their disease had more hemodynamic complications than the patients who did not have pH lower than 7.30 (p < 0.0001). Every case of cardiopulmonary arrest and shock was related to intramucosal pH of less than 7.30. Patients with major complications (cardiopulmonary arrest and shock) had lower intramucosal pHs than those with minor hemodynamic complications (p = 0.03); similarly, they had low intramucosal pH readings more often than those with minor complications (p = 0.0032). Intramucosal pH values less than 7.30 had a sensitivity of 90% and a specificity of 98% as a predictor of hemodynamic complications. There was no relation between intramucosal pH lower than 7.30 and either PRISM or the duration of the stay in the pediatric ICU. Patients with intramucosal pH less than 7.20 had a higher PRISM than the patients who did not have pH lower than 7.20 (p < 0.05). A patient who died during the study due to cardiopulmonary arrest had prior intramucosal pH measurements of 7.23 and 7.10, and three patients died of late complications after the end of the study. Hemodynamic complications were not detected with arterial pH. Gap pH (arterial pH-intramucosal pH) and standard pH measurements yielded the same results as gastric intramucosal pH. CONCLUSION: Intramucosal pH could provide a useful early indication of hemodynamic complications in critically ill children.     

The care of critically ill children in adult ICUs: the way forward

It is unlikely that in the short or medium term the PIC service can be restructured to such an extent that no children would need to be admitted to an adult ICU. Until this is the case the contribution of adult ICUs to the provision of PIC should be acknowledged and formally recognised as part of the service. Furthermore, there should be active support for these units from major/regional centres. There are clearly only a few adult ICUs which admit significant numbers of children. However, a more detailed analysis of adult ICUs is required to identify units which have available the full range of facilities, support services and appropriate staff to care for critically ill children. It is likely that only a few adult ICUs could meet the recommendations above, and it is in these units where efforts need to be concentrated. It is imperative that any nationally agreed standards or guidelines for PIC must apply equally to both adult ICU and paediatric ICU.     

Reversing oliguria in critically ill patients

Oliguria is a common occurrence in the ICU setting. In patients with preserved renal function, fluid challenges or low doses of diuretics are generally successful. In patients with oliguric renal failure, it is still essential to ensure adequate intravascular fluid volume, especially in critically ill patients. Loop diuretics remain the mainstay of treatment. When diuretic resistance is encountered, physicians should consider further optimization of hemodynamics, alternative loop diuretics, and combined drug therapy. In some cases, continuous renal replacement therapy can be very effective. Yet, while these interventions can help reduce the morbidity of severe volume overload, they have not been shown to improve mortality rates.     

Evaluation of a continuous cardiac output and mixed venous oxygen saturation catheter in critically ill surgical patients

OBJECTIVE: To evaluate the agreement of continuous cardiac output and mixed venous oxygen saturation measurements, obtained with a modified pulmonary artery catheter, with those values obtained by standard intermittent bolus thermodilution and cooximetry. DESIGN: Prospective, clinical investigation. SETTING: A surgical intensive care unit in a tertiary referral center. PATIENTS: Twenty-one adult critically ill surgical patients, requiring pulmonary artery catheter monitoring. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: A modified pulmonary artery catheter capable of continuous monitoring of cardiac output and mixed venous oxygen saturation was used with either an 8.5-Fr or a 9-Fr introducer. At random intervals, the continuous cardiac output measurement was compared with the cardiac output obtained using standard intermittent bolus thermodilution. The system was calibrated every 24 hrs for mixed venous oxygen saturation monitoring. Each saturation obtained by the laboratory cooximeter was compared with that value recorded using the catheter. Data points for 202 pairs of cardiac output (21 patients, 31 catheters) and 65 pairs of mixed venous oxygen saturation (20 patients, 28 catheters) were obtained. The bias and precision of the cardiac output data were 0.49 and 1.01 L/min, respectively. The agreement between the continuous and bolus values decreased as the cardiac output increased. Heart rate did not affect the agreement between the continuous and bolus techniques. The bias and precision of the mixed venous oxygen saturation data were -0.57% and 3.76%, respectively. The hematocrit did not affect the bias or precision of the venous saturation data over the hematocrit range observed (23.2% to 44.6%). Fewer catheter malfunctions were observed when the catheter was used with a 9-Fr introducer than with an 8.5-Fr introducer. CONCLUSIONS: The test catheter adequately measures continuous cardiac output and mixed venous oxygen saturation in the clinical setting. Because intermittent bolus thermodilution is not a true "gold standard" for cardiac output determination, new techniques compared with bolus thermodilution may fail to achieve accuracy expectations. A 9-Fr introducer is recommended, as fiberoptic damage may have occurred when the 8.5-Fr introducer was used.     

Noninvasive assessment of cardiac output in critically ill patients by analysis of the finger blood pressure waveform

OBJECTIVE: To assess whether the measurement of cardiac output by computer-assisted analysis of the finger blood pressure waveform can substitute for the thermodilution method in critically ill patients. DESIGN: Prospective data collection. SETTING: Emergency department in a 2000-bed inner city hospital PATIENTS: Forty-six critically ill patients requiring invasive monitoring for clinical management were prospectively studied. INTERVENTIONS: Under local anesthesia a 7-Fr pulmonary artery catheter was inserted via the central subclavian or jugular vein. Cardiac output was determined by the use of a cardiac output computer and injections of 10 mL ice-cold glucose 5%. Noninvasive cardiac output was calculated from the finger blood pressure waveform by the use of the test software program. MEASUREMENTS AND MAIN RESULTS: Three hundred twenty-three pairs of invasive and noninvasive hemodynamic measurements were collected in intervals of 30 mins from 46 patients (mean age 61.9 +/- 12.4 yrs; 35 male, 11 female). The average cardiac index during the study period was 2.83 L/min/m2 (range 0.97 to 5.56). The overall discrepancy between both measurements was 0.14 L/min/m2 (95% confidence interval: 0.10-.018, p < .001). Seventy-five (23.2%) measurements had an absolute discrepancy > +/- 0.50 L/min/m2. Noninvasive and invasive comparisons of mean differential cardiac output were out of phase for 9.7% of all readings. CONCLUSION: Computer-assisted analysis of finger blood pressure waveform to assess cardiac output is not a substitute for the thermodilution method due to a high percentage (23.2%) of inaccurate readings; however, it may be a useful tool for the detection of relative hemodynamic trends in critically ill patients.