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Biomedical subjects

W Butt

Publications and source records attributed to W Butt.

At least 37 records · Page 2Linked to original sources
PubMed1998

Pulse oximetry for assessment of pulsus paradoxus: a clinical study in children.

OBJECTIVE: To evaluate the relationship between intraarterial measured pulsus paradoxus (PP) and photoplethysmographic wave changes. SETTING: Tertiary pediatric intensive care unit. PATIENTS: 62 nonintubated children with or without respiratory disorders. DESIGN: Prospective, clinical study. MEASUREMENTS AND RESULTS: Simultaneous paper recordings of photoplethysmographic wave, arterial blood pressure, breathing cycle and electrocardiogram. The respiratory dependent changes of the plethysmographic respiratory wave (delta pleth, mm) were defined as the difference between the highest value of the upper peak of the wave (in expiration) and the lowest value of the upper peak (in inspiration). In each patient, ten consecutive breaths were averaged for analysis. Five recordings could not be evaluated (movement artifacts). In 57 children (median age 2.4 years, range 7 days to 17 years), the photoplethysmographic fluctuations (delta pleth, mm) correlated with PP (mm Hg). r = 0.85; 95% confidence interval (CI), 0.76 to 0.91. The sensitivity to detect a PP of > 10 mmHg with a plethysmographic fluctuation of > 8 mm was 89% (95% CI, 77 to 100%) and the specificity was 90% (95% CI, 79 to 100%). CONCLUSIONS: Pulse oximetry appears to be a rapid and easily performed, noninvasive method for the objective estimation of the degree of PP.

Adolescent↗
PubMed1997

Extracorporeal support for intractable cardiorespiratory failure due to meningococcal disease.

BACKGROUND: Meningococcal disease is still associated with considerable mortality, despite the use of early antibiotics and management in specialised intensive care units, due principally to early refractory myocardial depression and hypotension as well as severe acute respiratory distress syndrome. Extracorporeal membrane oxygenation (ECMO) is a complex technology that uses a modified "heart-lung" machine to provide temporary cardiac and respiratory support. We reviewed the UK and Australian experience of the use of ECMO in patients with refractory cardiorespiratory failure due to meningococcal disease. METHODS: The records from all 12 known patients supported with ECMO for meningococcal disease in the UK and Australia since 1989 were reviewed. FINDINGS: 12 patients (aged 4 months to 18 years, median 26 months) with meningococcal disease received ECMO over 8 years. In seven patients, ECMO was required early for cardiac support for intractable shock within 36 h of admission to intensive care. In the other five patients, ECMO was indicated for respiratory failure due to severe adult respiratory distress syndrome, which tended to occur later in the disease. The paediatric risk of mortality score ranged from 13 to 40 (median 29, median predicted risk of mortality 72%). Six of the 12 patients required cardiopulmonary resuscitation before ECMO and the other six were deteriorating despite maximal conventional therapy. Overall, eight of the 12 patients survived, with six leading functionally normal lives at a median of 1 year (range 4 months to 4 years) of follow-up. INTERPRETATION: ECMO might be considered to support patients with intractable cardiorespiratory failure due to meningococcal disease who are not responding to conventional treatment.

Adolescent↗
PubMed1997

Predictors of mortality and multiple organ failure in children with sepsis.

OBJECTIVES: To assess the markers of perfusion which best discriminate survivors from non-survivors of childhood sepsis and to compare the information derived from gastric tonometry with conventionally measured haemodynamic and laboratory parameters. DESIGN: Prospective clinical study of children with sepsis syndrome or septic shock. SETTING: Paediatric intensive care unit in a tertiary referral centre. PATIENTS: 31 children with sepsis syndrome or septic shock. INTERVENTIONS: A tonometer was passed into the stomach via the orogastric route. MEASUREMENTS AND MAIN RESULTS: The following data were recorded at admission, 12, 24 and 48 h: heart rate, mean arterial pressure, arterial pH, base deficit, arterial lactate, gastric intramucosal pH (pHi) and DCO2 (intramucosal carbon dioxide tension minus arterial partial pressure of carbon dioxide). The principal outcome measure was. The secondary outcome measure was the number of organ systems failing at 48 h after admission. There were 10 deaths and 21 survivors. No variable discriminated survival from death at presentation. Blood lactate level was the earliest discriminator of survival. Using univariate logistic regression, lactate discriminated survivors from those who died at 12 and 24 h after admission, but not at 48 h (p = 0.049, 0.044 and 0.062, respectively). The area under the receiver operating characteristic (ROC) curve for lactate was 0.81, 0.88 and 0.89 at 12, 24 and 48 h, respectively. At 12 h after admission, a blood lactate level > 3 mmol/l had a positive predictive value for death of 56% and a lactate level of 3 mmol/l or less had a positive predictive value for survival of 84%. At 24 h a lactate level > 3 mmol/l had a positive predictive value for death of 71% and a level of 3 mmol/l or less had a positive predictive value for survival of 86%. No other variable identified non-survivors from survivors at 12 h. Gastric tonometry could only be done on 19 of the 31 children, of whom 8 died and 11 survived. In these 19 children, DCO2 measured at 24 h, but not at 12 or 48 h, distinguished those who died from those who survived (p = 0.045 and p = 0.20, respectively). The area under the ROC curve for DCO2 measured at 24 h as a predictor of survival was 0.71. Neither the absolute value of pHi nor the trend of change in pHi at any time in the first 48 h identified survivors in this series. The mean arterial pressure distinguished survivors from non-survivors at 24 and 48 h (area under ROC curve = 0.80 and 0.78, respectively). The base deficit and heart rate did not identify non-survivors from survivors at any time in the first 48 h. CONCLUSIONS: Blood lactate level was the earliest predictor of outcome in children with sepsis. In this group of patients, gastric tonometry added little to the clinical information that could be derived more simply by other means.

Adolescent↗
PubMed1997

Early markers of major adverse events in children after cardiac operations.

OBJECTIVES: The purpose of this study was to determine the physiologic variables that predict major adverse events in children in the intensive care unit after cardiac operations. METHODS: A cohort observational study was conducted. At the time of admission to the intensive care unit and 4, 8, 12, and 24 hours later the following variables were recorded: mean arterial pressure, heart rate, cardiac index, oxygen delivery, mixed venous oxygen saturation, base deficit, blood lactate, gastric intramucosal pH, carbon dioxide difference (the difference between arterial carbon dioxide tension and gastric intraluminal carbon dioxide tension), and toe-core temperature gradient. Major adverse events were prospectively identified as cardiac arrest, need for emergency chest opening, development of multiple organ failure, and death. RESULTS: Ninety children were included in the study; 12 had major adverse events and there were 4 deaths. Blood lactate level, mean arterial pressure, and duration of cardiopulmonary bypass were the only significant, independent predictors of major adverse events when measured at the time of admission to the intensive care unit. The odds ratio (95% confidence intervals) for major adverse events if a lactate level was greater than 4.5 mmol/L was 5.1 (1.2 to 21.1), for admission hypotension 2.3 (0.5 to 9.8), and for a cardiopulmonary bypass time greater than 150 minutes 13.7 (3.3 to 57.2). Four hours after admission lactate and carbon dioxide difference, and 8 hours after admission lactate and base deficit, were independently significant predictors. The odds ratios for major adverse events if the blood lactate level was greater than 4 mmol/L at 4 and 8 hours were 8.3 (1.8 to 38.4) and 9.3 (1.9 to 44.3), respectively. At no time in the first 24 hours were cardiac output, oxygen delivery, mixed venous oxygen saturation, toe-core temperature gradient, or heart rate significant predictors of major adverse events. CONCLUSIONS: In the context of our current treatment strategies, the duration of cardiopulmonary bypass and blood lactate level, measured in the early postoperative period, were the best predictors of impending major adverse events.

Blood Pressure↗
PubMed1997

Extreme sodium derangement in a paediatric inpatient population.

OBJECTIVE: To determine the aetiology, symptoms and outcome of extreme sodium derangement in a paediatric inpatient population. METHODOLOGY: A retrospective study of children with extreme disturbance of their plasma sodium (> or = 165 mmol/L or < or = 115 mmol/L) admitted to a tertiary referral centre during a 72-month period. RESULTS: Twenty-seven cases of hypernatraemia and 21 of hyponatraemia were reviewed. Sodium disturbance developed after hospital admission in 27/57 cases (57%). Gastroenteritis was the most common cause of hypernatraemia (8/27; 30%), four of 27 (15%) had iatrogenic hypernatraemia. Water overload accounted for 8/21 (38%) cases of hyponatraemia. Neurologic symptoms occurred in 19/24 (79%) with hypernatraemia and in 11/19 (58%) with hyponatraemia. Ten (37%) with hypernatraemia and four (19%) with hyponatraemia died. A deterioration in functional status was seen in two patients with hypernatraemia. There was no apparent deterioration in the survivors with hyponatraemia. CONCLUSION: Extreme sodium disturbance often develops after admission to hospital and is caused by a variety of diseases and interventions. Neurologic symptoms are common and the mortality rate is high. The outcome in survivors is survivors is most likely to be dependent on the underlying disease process.

Child↗
PubMed1997

The DCO2 measured by gastric tonometry predicts survival in children receiving extracorporeal life support. Comparison with other hemodynamic and biochemical information. Royal Children's Hospital ECMO Nursing Team.

STUDY OBJECTIVE: To assess the role of gastric tonometry in monitoring children receiving extracorporeal life support (ECLS) and to determine if DCO2 or pHi in the weaning phase of ECLS predicts survival. DESIGN: A prospective study of consecutive patients treated with ECLS. SETTING: A tertiary pediatric ICU that is the ECLS referral center for Australia. PATIENTS: Twenty consecutive children receiving ECLS for cardiovascular or respiratory failure. INTERVENTIONS: All children were monitored throughout their ECLS course using a tonometer inserted into the stomach via the orogastric route. The PCO2 in the tonometer balloon was measured every 4 to 6 h and the pHi was calculated using the Henderson-Hasselbalch equation. The DCO2, which is the difference between PCO2 in tonometer saline solution and arterial blood, was calculated. We compared the ability of pHi, DCO2, heart rate, mean arterial pressure, arterial pH, base deficit, and blood lactate to predict death or survival during the weaning phase. Measurements were taken on the lowest level of support, which for veno-arterial extracorporeal membrane oxygenation and ventricular assist device was defined as the lowest ECLS pump flows, and on veno-venous extracorporeal membrane oxygenation was defined as the time of lowest ECLS gas flow. Predictive power was assessed using the receivor operating characteristic (ROC) analysis on the data collected at these times. RESULTS: In the weaning phase of ECLS, the pHi was significantly lower in children who died (pHi = 7.21; 95% confidence intervals, 7.14 to 7.28) than in those who survived (pHi = 7.38; 95% confidence intervals, 7.28 to 7.47). The DCO2 was significantly higher in children who died (23.6 mm Hg; 95% confidence intervals, 14.3 to 33.1) compared with survivors (4.7 mm Hg; 95% confidence intervals, -0.78 to 10.1). The area under the ROC curve was 0.95 for DCO2 (and 0.88 for pHi). pHi and DCO2 predicted survival better than base deficit (area under ROC curve, 0.82), blood lactate level (0.29), arterial pH (0.65), heart rate (0.62), and mean arterial pressure (0.74). CONCLUSIONS: DCO2 is a clinically meaningful measurement in children receiving ECLS. A high DCO2 was a good predictor of death in this series. Gastric tonometry may provide a useful measure of the adequacy of regional perfusion and oxygenation in this group of patients.

Acidosis↗
PubMed1996

The outcome of children admitted to intensive care with meningococcal septicaemia.

OBJECTIVE: To review our experience of children with meningococcal septicaemia, and to validate, in our group, severity scores used in different populations to predict outcome. DESIGN: Retrospective review of case notes and charts. PATIENTS: A total of 35 children were admitted to the paediatric intensive care unit (ICU) in the Royal Children's Hospital (RCH) in the 8 years between January 1985 and December 1992 with proven meningococcal septicaemia. RESULTS: Ages ranged from 4 months to 16 years, with a median age of 20 months. The median meningococcal score was 4 and the median PRISM score was 20, with scores above these being significantly associated with death (P < 0.0001). Thirty-two children (91%) received infusions of colloid for hypovolaemia and twenty-nine (83%) received one or more inotropic drugs. Twenty-one children (60%) required mechanical ventilation for a median of 16.5 h (range 7-574). Seven children (20%) underwent plasmapheresis. Six children (17%) underwent haemofiltration and two (6%), peritoneal dialysis. One patient received extracorporeal membrane oxygenation (ECMO) because of circulatory failure. Twenty-one children (60%) developed disseminated intravascular coagulation, renal failure and/or skin or limb necrosis. The overall survival was 66%, and all survivors are functionally normal. CONCLUSION: The mortality from the disease remains at 34% despite the technological advances in intensive care. The PRISM and meningococcal scores are useful in predicting outcome. Novel methods of treatment (e.g., plasmapheresis or ECMO) may be valuable.

Adolescent↗
PubMed1995

Somatosensory evoked potentials for prediction of outcome in acute severe brain injury.

The purpose of this study was to evaluate prospectively short-latency somatosensory evoked potentials (SEPs) as a predictor of outcome in acute, severe brain injury, and to compare this with the predictive power of the motor component of the Glasgow Coma Scale score and computed tomographic scan. Outcome was measured with the Glasgow Outcome Scale at a minimum of 6 months after injury. We studied 109 patients (aged 0.1 to 16.8 years) with SEPs within 4 days of the onset of coma. Four patients had absent SEPs and a favorable outcome by the Glasgow Outcome Scale (full recovery or moderate disability); two of these patients had meningitis with bilateral subdural effusions, one had a midbrain hemorrhage, and one had a decompressive craniectomy for uncontrolled intracranial hypertension. Normal SEPs had a positive predictive value for favorable outcome of 93% (95% confidence interval (CI), 77% to 99%), and absent SEPs had a positive predictive value for unfavorable outcome by the Glasgow Outcome Scale (severe disability, survival in a persistent vegetative state, or death) of 92% (95% CI, 80% to 98%). If the above identifiable clinical situations in which a physical barrier existed to impede cutaneous reception of the electrical impulse were excluded, the positive predictive value of absent SEPs for poor outcome reached 100% (95% CI, 92% to 100%). An absent motor response to painful stimulus also had 100% positive predictive value (95% CI, 84% to 100%) for unfavorable outcome; however, 23% of patients could not be evaluated because of the effects of muscle relaxants or sedatives. In patients with traumatic brain injury, results of computed tomography did not reliably predict outcome. Of the 59 patients with unfavorable outcome, 76% could be identified with SEPs compared with 36% with examination of motor function. We suggest that SEPs be performed in children with acute severe brain injury because they add an important tool to the physician's prognostic armamentarium. We conclude that in the absence of the above mentioned identifiable clinical situations, absent SEPs predict 100% unfavorable outcome, and this finding may warrant consideration of withdrawal of treatment in children with brain injuries.

Acute Disease↗
PubMed1995

Inferior vena cava pressure as an estimate of central venous pressure.

OBJECTIVE: To determine whether pressure in the inferior vena cava (IVC) is similar to central venous pressure. METHODOLOGY: Prospective measurement of both central venous pressure (CVP) and inferior vena cava pressure (IVCP) in the same child; each child had to have both catheters in situ. Two measurements of each pressure in reverse order (IVCP then CVP, and CVP then IVCP) were done and the mean of each was recorded. Comparison of the pressures was performed using the method of Bland and Altman. RESULTS: Thirty-nine children had pressures recorded. The CVP ranged from 3 to 17 mmHg. In 22 of 39 measurements IVCP was equal to CVP; in 33 of 39 measurements IVCP was different from CVP by 1 mm or less and in 37 of 39 measurements IVCP was different from CVP by 2 mm or less. The mean difference between IVCP and CVP was +0.33 mmHg, the 95% confidence interval was 2.26 to +2.93 mmHg. CONCLUSION: Measurement of IVCP is a good approximation to CVP and can be routinely used in clinical care of children who do not have raised intra-abdominal pressure.

Adolescent↗
PubMed1994

Predictors of survival for infants with congenital diaphragmatic hernia.

Over the past decade, the survival rate of infants with congenital diaphragmatic hernia (CDH) treated in the intensive care unit of the Royal Children's Hospital, Melbourne, has remained unchanged at 56% +/- 6%. Newer forms of treatment, such as extracorporeal membrane oxygenation (ECMO), high-frequency oscillation, and surfactant and nitric oxide therapy, are now available. The exact role of these therapies in the management of infants with CDH has not been determined. This study examines five clinical parameters derived from an infant's best preoperative ventilatory and blood gas data in the first 24 hours of life. One hundred twenty-five CDH infants were admitted to the intensive care unit between January 1, 1981 and December 31, 1991. Criteria for inclusion in the study were (1) CDH diagnosed within 6 hours of delivery, (2) ventilation before repair, and (3) no associated lethal congenital abnormality. Of the 90 cases studied in detail, there were 38 deaths (42% mortality rate). All five parameters were analyzed by receiver operating curve analysis to determine the optimum value of each parameter in predicting survival. An oxygenation index (MAP x FIO2/PaO2) of less than 0.08 predicted a 94% chance of survival, with a sensitivity of 96% and a specificity of 95%. Similarly, a modified ventilation index (PIP x RR x CO2/1,000) of less than 40 predicted a 91% chance of survival, with a sensitivity of 94% and a specificity of 86%. By stratifying each criterion according to outcome, three groups of infants were identified according to their response to conventional therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Hernia, Diaphragmatic↗
PubMed1994

Extracorporeal membrane oxygenation for refractory septic shock in children.

OBJECTIVE: To review demographic data and outcome of children who received extracorporeal membrane oxygenation (ECMO) for refractory septic shock. METHOD: Review of medical charts of nine children receiving ECMO for culture-proven refractory septic shock treated in a multidisciplinary pediatric intensive care unit. RESULTS: Median age was 12 years and median weight was 45 kg. Median inotrope requirements (micrograms/kg per minute) before ECMO were dopamine, 15; dobutamine, 12.5; epinephrine, 4; and norepinephrine, 3.5. Four children received two inotropes concurrently, and five received three or more. All nine patients had severe respiratory failure; eight had evidence of other organ system dysfunction, with six having five or more organ system dysfunctions. Median PRISM score was 27. Median duration of ECMO was 137 hours. Within 24 hours of starting ECMO, 7 of 9 children had all inotropes stopped. Four patients died and five survived, all of whom are leading normal lives. CONCLUSION: In this small group of children with probably fatal septic shock, ECMO was successfully supported the circulation and 5 of the 9 children survived. We suggest that septic shock should not be considered a contraindication to ECMO.

Adolescent↗
PubMed1993

Suppression of brainstem reflexes in barbiturate coma.

Brainstem reflexes were examined in 23 children treated with thiopentone infusion and correlated with serum thiopentone concentrations. The results suggest that if all brainstem reflexes are lost with a serum thiopentone concentration less than 40 mg/l, it is unlikely to be due to the thiopentone alone. Other causes including brain death need to be considered.

Adolescent↗
PubMed1992

Treatment of neonatal hyperbilirubinaemia by plasmapheresis.

A term baby developed severe hyperbilirubinaemia in association with group-B streptococcal sepsis. Haemodynamic instability deterred us from performing exchange transfusion, and so plasmapheresis was used to lower the bilirubin level. The procedure was very effective and well tolerated.

Bacteremia↗
PubMed1992

Drug errors in intensive care.

Errors in prescription, administration, delivery and interaction of drugs are likely in children in intensive care units because of the large number of often unfamiliar medications these children receive. We evaluated prospectively the frequency and consequence of drug errors in a large multidisciplinary intensive care unit. There was a mistake in drug prescription, administration, delivery or drug interaction in 2% of medication orders, with 12% of these mistakes causing actual harm to the patient. The frequency of drug errors must be appreciated and due care must be taken in checking and delivering drugs to children in an intensive care unit.

Australia↗
PubMed1992

Outcome of infants with birthweight 2000 g or less who undergo major cardiac surgery.

A retrospective study of all neonates with birthweight 2000 g or less undergoing major cardiac surgery at the Royal Children's Hospital, Melbourne over the last 5 years was performed in order to determine outcome and identify subgroups within this population that may have a poor prognosis. The mean length of stay in intensive care following surgery was 32 days, with non-survivors having a significantly longer duration of stay than survivors. Overall mortality was 43%, and for children with congenital heart disease as part of a recognizable syndrome the mortality was 100%. None of the survivors suffered incapacitating cardiac, neurological or respiratory handicap. These children in general have a poor prognosis and utilize significant resources; results of cardiac surgery in this group need to be closely followed in the future.

Cardiac Surgical Procedures↗