Excessive predicted mortality in acute hypoxemic respiratory failure?
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Adolescent↗
Biomedical subjects
I A Murdoch
Publications and source records attributed to I A Murdoch.
Use of transesophageal Doppler ultrasonography in ventilated pediatric patients: derivation of cardiac output.
OBJECTIVE: To ascertain if cardiac output (CO) could be derived from blood flow velocity measured in the descending aorta of ventilated children by transesophageal Doppler ultrasonography (TED) without the need for direct aortic cross sectional area measurement, and to evaluate the ability of TED to follow changes in CO when compared with femoral artery thermodilution. DESIGN: Prospective, comparison study. SETTING: A 16-bed pediatric intensive care unit of a university hospital. PATIENTS: A total of 100 ventilated infants and children aged 4 days to 18 yrs (median age, 27 months). Diagnoses included postcardiac surgery (n = 58), sepsis/multiple organ failure (n = 32), respiratory disease (n = 5), and other (n = 5). A total of 55 patients were receiving inotropes or vasodilators. INTERVENTIONS: When patients were hemodynamically stable, a TED probe was placed into the distal esophagus to obtain optimal signal, and minute distance (MD) was recorded. Five consecutive MD measurements were made concurrently with five femoral artery thermodilution measurements, and the concurrent measurements were averaged. CO was then manipulated by fluid administration or inotrope adjustment, and the readings were repeated. MEASUREMENTS AND MAIN RESULTS: Femoral artery thermodilution CO ranged from 0.32 to 9.19 L/min, (median, 2.46 L/min), and encompassed a wide range of high and low flow states. Theoretical consideration revealed the optimal TED estimate for CO to be (MD x patient height2 x 10(-7)). Linear regression analysis yielded a power function model such that: estimated CO = 1.158 x (MD x height2 x 10(-7))(0.785), r2 = 0.879, standard error of the estimate = 0.266. Inclusion of a correction factor for potential changes in aortic cross-sectional area with hypo- and hypertension did not appreciably improve the predictive value of the model. MD was able to follow percentage changes in CO, giving a mean bias of 0.87% (95% confidence interval -0.85% to 2.59%), and limits of agreement of +/- 16.82%. The median coefficient of variation for MD was 3.3%. CONCLUSIONS: TED provides a clinically accurate estimate of CO across the entire pediatric age range and is able to follow changes in CO.
Adolescent↗
Procalcitonin and cytokine levels: relationship to organ failure and mortality in pediatric septic shock.
BACKGROUND: Procalcitonin (PCT), a marker of bacterial sepsis, may also act as a mediator of the inflammatory response to infection, and thus influence outcome. OBJECTIVE: To investigate the relationship between PCT, interleukin (IL)-10, tumor necrosis factor (TNF), organ failure, and mortality in pediatric septic shock. DESIGN: Prospective observational study. SETTING: A 16-bed pediatric intensive care unit of a university hospital. PATIENTS: A total of 75 children with septic shock having a median age of 43.1 months (range, 0.1-192 months). Children who had received antibiotics for >24 hrs were excluded. A total of 37 patients (49%) had meningococcal disease, and 72 patients (96%) required mechanical ventilation. INTERVENTIONS: The pediatric risk of mortality (PRISM) score, multiple organ system failure (MOSF) score, duration of ventilation, length of ICU stay, and outcome were recorded. PCT, IL-10, and TNF were measured at admission to the intensive care unit. Sequential PCT levels were available at 0 hrs and 24 hrs in 39 patients (52%). RESULTS: Observed mortality was 21/75 (28%). Data are median (range). The admission PCT (p = .0002) and TNF levels (p = .0001) were higher in children with higher MOSF scores. In survivors and nonsurvivors, the admission PCT was 82 ng/mL vs. 273 ng/mL (p = .03), IL-10 was 62 pg/mL vs. 534 pg/mL (p = .03), and TNF was 76 pg/mL vs. 480 pg/mL (p = .001), respectively. Area under the mortality receiver operating characteristic curve was 0.73 for PCT, 0.67 for IL-10, and 0.76 for TNF, compared with 0.83 for the PRISM score. Of 39 children, 16 (41%) with sequential PCT measurements showed no fall in PCT after 24 hrs treatment. These children had higher admission levels of IL-10 (p = .03), and TNF (p = .03) compared with children who demonstrated a subsequent fall in PCT. Although the former did not have a higher median PRISM (p = .28) or MOSF score (p = .19), observed mortality was 44% (7 of 16) compared with 9% (2 of 23) (p = .02). CONCLUSION: The admission PCT, like TNF and IL-10, is related to the severity of organ failure and mortality in children with septic shock. A fall in PCT after 24 hrs of treatment may have favorable prognostic significance.
Adolescent↗
Chasing the base deficit: hyperchloraemic acidosis following 0.9% saline fluid resuscitation.
Base deficit is a parameter often used to guide further treatment in acidotic children and is taken as a measure of how "sick" they are. Five children with septic shock are presented who had persisting base deficit after large volume resuscitation with 0.9% saline. Stewart's strong ion theory of acid-base balance is able to quantify the causes of metabolic acidosis and is used to show that our patients had a hyperchloraemic metabolic acidosis. We show how the chloride content of the saline loads given to our patients caused this hyperchloraemia. It is concluded that 0.9% saline and other chloride rich fluids may not be ideal resuscitation fluids; if used, clinicians must be aware of their potential to cause a persistent base deficit.
Acidosis↗
Exogenous surfactant supplementation in infants with respiratory syncytial virus bronchiolitis.
Infants with respiratory syncytial virus (RSV) bronchiolitis are deficient in surfactant, both in quantity and ability to reduce surface tension. New evidence suggests surfactant has a role in maintaining the patency of conducting airways, which has implications for RSV bronchiolitis. A randomized, controlled pilot study was undertaken to assess the effects of exogenous surfactant supplementation to RSV-positive infants on pulmonary mechanics, indices of gas exchange, and the phospholipid composition of bronchoalveolar lavage fluid (BALF). Nineteen ventilated infants (median corrected age 4 wk) received either two doses of surfactant (Survanta, 100 mg/kg) within 24 and 48 h of mechanical ventilation (n = 9), or air placebo (n = 10). Static lung compliance and resistance of infants in the placebo but not in the surfactant-treated group became progressively worse over the first 30 h following enrollment. Although no significant acute changes in gas exchange parameters were seen following surfactant, infants in the surfactant group showed a more rapid improvement in oxygenation and ventilation indices over the first 60 h of ventilation. Surfactant status was assessed from the concentration ratio in BALF of the disaturated phospholipid species dipalmitoylphosphatidylcholine to that of the monounsaturated species palmitoyloleoylphosphatidylcholine. This ratio correlated with both lung compliance (positively) and resistance (negatively), and over time increased in the treated group and declined in placebo infants. The data from this pilot study suggest that functional surfactant has a role in maintaining small airway patency as well as lung compliance in infants infected with RSV and an outcome study is now warranted.
Bronchiolitis, Viral↗
Use of permissive hypercapnia in the ventilation of infants with respiratory syncytial virus infection.
UNLABELLED: We wished to retrospectively evaluate the effects of permissive hypercapnia (PHY) on barotrauma, mortality and length of stay when applied to ventilated infants with respiratory syncytial virus (RSV) bronchiolitis. Nineteen control infants with RSV induced respiratory failure were treated with conventional ventilation (April 1991-January 1994), after which time PHY was adopted as unit policy. A further 28 infants were then treated with PHY (January 1994 April 1996). Demographic and physiological data were collected from admission, and outcome variables including length of stay, barotrauma and mortality were recorded. The PHY group showed a significantly higher mean pCO2 (7.6 vs 5.2 kPa), a lower mean pH (7.34 vs 7.40), and a reduction in maximal peak inspiratory pressures (25 vs 30 cmH2O). Mortality, barotrauma, use of neuromuscular blockade and nosocomial infection did not differ between groups. There was a trend towards increased length of ventilation in the PHY group (median 7 vs 5 days). CONCLUSION: Based on this retrospective data we can show no benefit for the use of permissive hypercapnia as a ventilatory strategy in this patient group. A prospective randomised controlled trial is warranted to accurately assess the outcome variables and cost implications of this strategy.
Barotrauma↗
Guillain-Barré syndrome: delayed diagnosis following anaesthesia.
Guillain-Barré syndrome following anaesthesia or surgery is rare. Diagnosis is often delayed, which may lead to an increase in morbidity. There is now good evidence that early diagnosis and treatment reduces this morbidity. The two cases highlight the difficulties with diagnosis in the perioperative period and further discuss the aetiology, diagnostic features and complications of childhood Guillain-Barré syndrome.
Anesthesia, General↗
Pediatric gastric tonometry: lessons from the adult experience.
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Adult↗
Adrenal insufficiency in septic shock.
BACKGROUND: Functional adrenal insufficiency has been documented in critically ill adults. OBJECTIVE: To document the incidence of adrenal insufficiency in children with septic shock, and to evaluate its effect on catecholamine requirements, duration of intensive care, and mortality. SETTING: Sixteen-bed paediatric intensive care unit in a university hospital. METHODS: Thirty three children with septic shock were enrolled. Adrenal function was assessed by the maximum cortisol response after synthetic adrenocorticotropin stimulation (short Synacthen test). Insufficiency was defined as a post-Synacthen cortisol increment < 200 nmol/l. RESULTS: Overall mortality was 33%. The incidence of adrenal insufficiency was 52% and children with adrenal insufficiency were significantly older and tended to have higher paediatric risk of mortality scores. They also required higher dose vasopressors for haemodynamic stability. In the survivor group, those with adrenal insufficiency needed a longer period of inotropic support than those with normal function (median, 3 v 2 days), but there was no significant difference in duration of ventilation (median, 4 days for each group) or length of stay (median, 5 v 4 days). Mortality was not significantly greater in children with adrenal insufficiency than in those with adequate adrenal function (6 of 17 v 5 of 16, respectively). CONCLUSION: Adrenal insufficiency is common in children with septic shock. It is associated with an increased vasopressor requirement and duration of shock.
Adolescent↗
Capillary refill and core-peripheral temperature gap as indicators of haemodynamic status in paediatric intensive care patients.
OBJECTIVES: Capillary refill time is an important diagnostic adjunct in the acute resuscitation phase of the shocked child. This study assesses its relation to commonly measured haemodynamic parameters in the postresuscitation phase when the child has reached the intensive care unit, and compares this with core-peripheral temperature gap. METHODS: Ninety standardised measurements of capillary refill time were made on 55 patients, who were divided into postcardiac surgery (n = 27), and general (n = 28), most of whom had septic shock (n = 24). A normal capillary refill time was defined as < or = 2 seconds. Measured haemodynamic variables included: cardiac index, central venous pressure, systemic vascular resistance index, stroke volume index (SVI), and blood lactate. Seventy measurements were made on patients while being treated with inotropes or vasodilators. RESULTS: Capillary refill time and temperature gap both correlated poorly with all haemodynamic variables among post-cardiac surgery children. For general patients, capillary refill time was related to SVI and lactate; temperature gap correlated poorly with all variables. General patients with a prolonged capillary refill time had a lower median SVI (28 v 38 ml/m2) but not a higher lactate (1.7 v 1.1 mmol/l). A capillary refill time of > or = 6 seconds had the best predictive value for a reduced SVI. CONCLUSION: Among ventilated, general intensive care patients, capillary refill time is related weakly to blood lactate and SVI. A normal value for capillary refill time of < or = 2 seconds has little predictive value and might be too conservative for this population; septic shock.
Body Temperature Regulation↗
Diagnostic markers of infection: comparison of procalcitonin with C reactive protein and leucocyte count.
BACKGROUND: Procalcitonin has been advocated as a marker of bacterial infection. OBJECTIVE: To evaluate diagnostic markers of infection in critically ill children, comparing procalcitonin with C reactive protein and leucocyte count in a paediatric intensive care unit (PICU). METHODS: Procalcitonin, C reactive protein, and leucocyte count were measured in 175 children, median age 16 months, on admission to the PICU. Patients were classified as: non-infected controls (43); viral infection (14); localised bacterial infection without shock (25); bacterial meningitis/encephalitis (10); or septic shock (77). Six children with "presumed septic shock" (without sufficient evidence of infection) were analysed separately. Optimum sensitivity, specificity, predictive values, and area under the receiver operating characteristic (ROC) curve were evaluated. RESULTS: Admission procalcitonin was significantly higher in children with septic shock (median 94.6; range 3.3-759.8 ng/ml), compared with localised bacterial infection (2.9; 0-24.3 ng/ml), viral infection (0.8; 0-4.4 ng/ml), and non-infected controls (0; 0-4.9 ng/ml). Children with bacterial meningitis had a median procalcitonin of 25.5 (7.2-118.4 ng/ml). Area under the ROC curve was 0.96 for procalcitonin, 0.83 for C reactive protein, and 0.51 for leucocyte count. Cut off concentrations for optimum prediction of septic shock were: procalcitonin > 20 ng/ml and C reactive protein > 50 mg/litre. A procalcitonin concentration > 2 ng/ml identified all patients with bacterial meningitis or septic shock. CONCLUSION: In critically ill children the admission procalcitonin concentration is a better diagnostic marker of infection than C reactive protein or leucocyte count. A procalcitonin concentration of 2 ng/ml might be useful in differentiating severe bacterial disease in infants and children.
Adolescent↗
Dilemmas exist in withdrawing ventilation from dying children.
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Child↗
Radiological case of the month. Sagittal sinus thrombosis in hypernatremic dehydration.
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Dehydration↗
The outcome of patients with upper airway obstruction transported to a regional paediatric intensive care unit.
UNLABELLED: The diagnoses, transfer, management and outcome of patients with upper airway obstruction (UAO) admitted from district general hospitals (DGH) to a regional paediatric intensive care unit were retrospectively reviewed over a 3.5-year period. Sixty-seven patient episodes were analysed. Fifty-two cases (78%) underwent tracheal intubation prior to transport with a low morbidity for both procedures. The most common diagnosis was viral croup (n = 34, 51%) with a median duration of intubation of 5 days, with subglottic stenosis being the next most common category (n = 10, 15%), median duration of intubation 7 days. Inhaled budesonide was used prior to intubation in 12 (35%) of those with croup, and inhaled bronchodilators in 28%, possibly reflecting diagnostic uncertainty. Patients with croup treated with budesonide were significantly less likely to require intubation (P = 0.04). The re-intubation rate for patients with viral croup was uncomfortably high at 16% (4/25) despite the routine use of prednisolone throughout the intubation period. Successful extubation of patients with viral croup could not be predicted by age (P = 0.31), length of intubation (P = 0.94), endotracheal tube size, (P = 0.60) abnormalities on the chest X-ray (P = 1.0), or presence of secondary bacterial infection (P = 0.23). CONCLUSION: Although viral croup remains the most common diagnostic category presenting at the DGH level with severe UAO, a wide range of other diagnoses is seen. Despite clear evidence of benefit, steroid administration to children presenting at the DGH with viral croup has not become routine practice. Once intubated, no reliable predictors of successful extubation were found amongst this patient group.
Airway Obstruction↗
Compartment syndrome and Varicella.
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Chickenpox↗
Early detection of necrotizing enterocolitis by gastrointestinal tonometry.
The diagnosis of necrotizing enterocolitis (NEC) in neonates has traditionally depended on a combination of clinical signs, biochemical parameters and radiological changes. The measurement of intramucosal pH by gastrointestinal tonometry provides a simple means of long-term monitoring which may detect the development of NEC before conventional techniques. We present our experience of tonometry in two 'at risk' term neonates with Hypoplastic Left Heart Syndrome.
Enterocolitis, Pseudomembranous↗
Gastric tonometry in septic shock.
OBJECTIVES: To investigate the prognostic value of intramucosal pH (pHi) and the relation among pHi, arterial pH, base excess, and lactate in children with septic shock. DESIGN: Children admitted to the paediatric intensive care unit with a diagnosis of septic shock were prospectively enrolled. A gastrointestinal tonometer (Tonometrics Division, Instrumentarium Corporation, Helsinki, Finland) was placed into the stomach and intramucosal pH, arterial pH, base deficit, and lactate were measured on admission and six hours later. Sequential data were analysed on 24 patients (17 survivors, seven non-survivors), median age 46 months (range: 2.8-168 months). RESULTS: Median pHi on admission was 7.39 (interquartile range 7.36-7.51) in survivors compared with 7.2 (interquartile range 7.18-7.35) in non-survivors (p = 0.01). There was no significant difference in arterial pH, base excess, or lactate among survivors and non-survivors. Admission pHi < 7.32 predicted mortality with sensitivity (57%), specificity (94%), and positive predictive value (80%). Patients with admission pHi < 7.32 who failed to improve > or = 7.32 within six hours (n = 3) had 100% mortality. CONCLUSION: In children with septic shock the admission pHi is significantly lower in non-survivors. pHi is a better prognostic indicator of mortality than either standard acid-base values or lactate. pHi < 7.32 that does not improve within six hours is associated with a poor prognosis.
Adolescent↗