Daniel Lutman

Hyperventilation in severe diabetic ketoacidosis

Objective: To explore whether the carbon dioxide-bicarbonate (Pco2-HCO3) buffering system in blood and cerebrospinal fluid (CSF) in diabetic ketoacidosis should influence the approach to ventilation in patients at risk of cerebral edema. Data Source: Medline search, manual search of references in articles found in Medline search, and use of historical literature from 1933 to 1967. Design: A clinical vignette is used—a child with severe diabetic ketoacidosis who presented with profound hypocapnia and then deteriorated—as a basis for discussion of integrative metabolic and vascular physiology. Study Selection: Studies included reports in diabetic ketoacidosis where arterial and CSF acid-base data have been presented. Studies where simultaneous acid-base, ventilation, respiratory quotient, and cerebral blood flow data are available. Data Extraction and Synthesis: We revisit a hypothesis and, by reassessing data, put forward an argument based on the significance of low [HCO3]CSF and rising Paco2; hyperventilation in diabetic ketoacidosis and the limit in biology of survival; repair of severe diabetic ketoacidosis and Paco2; and mechanical ventilation. Conclusion: The review highlights a potential problem with mechanical ventilation in severe diabetic ketoacidosis and suggests that the Pco2-HCO3 hypothesis is consistent with data on cerebral edema in diabetic ketoacidosis. It also indicates that the recommendation to avoid induced hyperventilation early in the course of intensive care may be counter to the logic of adaptive physiology.

Timing of Death In Children Referred For Intensive Care With Severe Sepsis: Implications For Interventional Studies

Objective: Early deaths in pediatric sepsis may limit the impact of therapies that can only be provided on PICUs. By introducing selection and survivorship biases, these very early deaths may also undermine the results of trials that employ standard consent procedures. We hypothesized that: 1) the majority of deaths in children with severe sepsis occur very early, within 24 hours of referral to PICU; and 2) a significant proportion of deaths occur before PICU admission. Design, Setting, and Patients: We studied consecutive referrals of newborns through to 16 years of age, between 2005 and 2011 to the Children’s Acute Transport Service, the North Thames regional pediatric intensive care transport service, with a working diagnosis of “sepsis,” “severe sepsis,” “meningococcal sepsis,” or “septic shock.” Interventions: The primary outcome measure was the proportion of deaths within 24 hours of referral. Survival distributions of previously healthy children were compared with those with significant comorbidities. Measurements and Main Results: Thirteen thousand four hundred and nine referrals were made to Children’s Acute Transport Service, of whom 703 (5%) met inclusion criteria. Data on survival to 1 year were available in 627 of 703 patients (89%). One hundred thirty children (130/627; 21%; 95% CI, 18–24%) died in the first year. A higher proportion of children with comorbidity cases (46/85, 54%, 44–64) died compared with previously healthy cases (84/542; 16%; 13–19; p < 0.0005, Fisher exact test). Seventy-one deaths occurred within 24 hours of PICU referral (71/130, 55%, 46–63). The timing of death differed with comorbidity. Similar proportions of children survived to 24 hours (previously healthy children 90% vs children with comorbidity 83%, p = 0.06). However, deaths after 24 hours were infrequent among previously healthy cases (28/84 deaths, 33%, 24–44%) compared with children with comorbidity cases (31/46 deaths, 66%, 53–79%) (p < 0.001, Fisher exact test). Conclusions: This majority of deaths among children referred for pediatric intensive care with for severe sepsis occur within 24 hours. This has important implications for future clinical trials and quality improvement initiatives aimed at improving sepsis outcomes.

Stabilisation of critically ill children at the district general hospital prior to intensive care retrieval: a snapshot of current practice

Objective To describe current practice during stabilisation of children presenting with critical illness to the district general hospital (DGH), preceding retrieval to intensive care. Design Observational study using prospectively collected transport data. Setting A centralised intensive care retrieval service in England and referring DGHs. Patients Emergency transports to intensive care during 2-month epochs from 4 consecutive years (2005–2008). Interventions None. Main outcome measures Proportion of key airway, breathing, and circulatory and neurological stabilisation procedures, such as endotracheal intubation, mechanical ventilation, vascular access, and initiation of inotropic agents, performed by referring hospital staff prior to the arrival of the retrieval team. Results 706 emergency retrievals were examined over a 4-year period. The median age of transported children was 10 months (IQR, 18 days to 43 months). DGH staff performed the majority of endotracheal intubations (93.7%, CI 91.3% to 95.5%), initiated mechanical ventilation in 76.9% of cases (CI 73.0% to 80.4%), inserted central venous catheters frequently (67.4%, CI 61.7% to 72.6%), and initiated inotropic agents in 43.7% (CI 36.6% to 51.1%). The retrieval team was more likely to perform interventions such as reintubation for air leak, repositioning of misplaced tracheal tubes, and administration of osmotic agents for raised intracranial pressure. The performance of one or more interventions by the retrieval team was associated with severity of illness, rather than patient age, diagnostic group, or team response time (OR 3.62, 95% CI 1.47 to 8.92). Conclusions DGH staff appropriately performs the majority of initial stabilisation procedures in critically ill children prior to retrieval. This practice has not changed significantly for the past 4 years, attesting to the crucial role played by district hospital staff in a centralised model of paediatric intensive care.

Inhaled nitric oxide in neonatal and paediatric transport.

Since the first reports of the use of inhaled nitric oxide in the early 1990s its applications have been refined to a number of specific conditions. Pre-term and term neonates benefit significantly in the improvement of oxygenation in conditions such as hypoxic respiratory failure and persistent pulmonary hypertension of the neonate and the reduction in referral rates to extra corporeal membrane oxygenation. Many neonatal units still do not have the ability to administer inhaled nitric oxide though an increasing number of neonatal units have acquired the capability to deliver inhaled nitric oxide in recent years with commercially available delivering devices. In either case if the neonate needs transfer for further management or extra corporeal membrane oxygenation the journey can be improved if inhaled nitric oxide is introduced during transport or could deteriorate if inhaled nitric oxide was discontinued during transport. Delivery of inhaled nitric oxide during transport can be technically challenging and the consequences of increased or interrupted delivery can be dangerous. The different modes of transport either by road or air can influence the method of delivery. We describe our method of delivering inhaled nitric oxide during the retrievals we undertake and how this changes depending upon the type of journey performed. We also suggest guidelines for its use during transport and outline the precautions we take to ensure safety of patient and carers during transport.

Shock Index Values and Trends in Pediatric Sepsis: Predictors or Therapeutic Targets? A Retrospective Observational Study.

Background: Shock index (SI) (heart rate [HR]/systolic blood pressure [SBP]) has been used to predict outcome in both adult and pediatric sepsis within the intensive care unit (ICU). We aimed to evaluate the utility of SI before pediatric ICU (PICU) admission. Patients and Methods: We conducted a retrospective observational study of children referred to a pediatric intensive care transport service (PICTS) between 2005 and 2011. The predictive value of SI, HR, and blood pressure at three prespecified time points (at referral to PICTS, at PICTS arrival at the referring hospital, and at PICU admission) and changes in SI between the time points were evaluated. Death within the first 48 h of ICU admission (early death) was the primary outcome variable. Results: Over the 7-year period, 633 children with sepsis were referred to the PICTS. Thirty-nine children died before transport to a PICU, whereas 474 were transported alive. Adjusting for age, time points, and time duration in a multilevel regression analysis, SI was significantly higher in those who died early. There was a significant improvement in SI with the transport team in survivors but not in nonsurvivors. However, the predictive value of a change in SI for mortality was no better than either a change in HR or blood pressure. Conclusions: The absolute or change in SI does not predict early death any more than HR and SBP individually in children with sepsis.

Effect of patient- and team-related factors on stabilization time during pediatric intensive care transport

Objectives: To examine the effects of patient- and transport-related factors on the time spent at the referring hospital by an intensive care retrieval team to stabilize critically ill children and to study the relationship between stabilization time and patient outcome. Design: Analysis of prospectively collected data during pediatric intensive care transport. Setting: A dedicated regional pediatric intensive care retrieval service performing interhospital transports in England. Patients: Critically ill children transported to intensive care units over a 2-yr period between April 1, 2006 and March 31, 2008. Interventions: None. Measurements and Main Results: Factors related to the patient (age group, diagnostic category, and severity of illness) and transport (time of referral, team response time, and number of major and minor interventions performed) were analyzed for their effect on stabilization time in univariate and multivariate analyses. The relationship between stabilization time and patient outcome in the first 24 hrs post intensive care unit admission was also studied. Patient acuity was high in the transported population (84% invasively ventilated; 28% on vasoactive agents). Predicted mortality risk (Pediatric Index of Mortality 2 score), diagnostic category, team response time, and number of major interventions performed had an independent effect on stabilization time, whereas the length of stabilization itself did not influence early mortality on the intensive care unit. Each minor intervention prolonged the stabilization time by an average of 10 mins. Conclusions: Stabilization time during intensive care transport is influenced by a number of patient- and transport-related factors, and cannot be used in isolation as an indicator of team efficiency. Time spent undertaking intensive care interventions early in the course of patient illness at the referring hospital does not worsen patient outcome, suggesting that the “scoop and run” model can be safely abandoned in interhospital transport.

Emergency management of children with acute severe asthma requiring transfer to intensive care

Purpose Children presenting to emergency departments (ED) with acute severe asthma unresponsive to initial medical therapy may require endotracheal intubation and mechanical ventilation. There is little data on complications during the acute management of children with life-threatening asthma, particularly at hospitals where specialist paediatric staff are lacking. It was hypothesised that a better understanding of complications, particularly associated with intubation and mechanical ventilation, would improve acute management in ED, aid quality improvement initiatives at district general hospitals (DGH) and form the basis for educational interventions from regional paediatric critical care units. Methods A retrospective case note review was performed for all children referred to a regional intensive care retrieval service with status asthmaticus over a 2-year period. Initial treatment, patient-related factors, indication for endotracheal intubation and the type and occurrence of adverse events during acute management at the DGH were studied. Bivariate and multivariate analyses were undertaken to identify factors associated with the occurrence of complications. Results 51 (85%) of the 60 children transferred to a paediatric intensive care unit for acute severe asthma required intubation. 36 (70.5%) experienced one or more complications during intubation and in the early phase of mechanical ventilation. The most common complications were hypotension (requiring fluid resuscitation and/or inotropic support) and severe bronchospasm with acute hypercarbia. The indication for intubation significantly affected the chances of a complication occurring during stabilisation. Conclusions There is considerable morbidity in asthmatic children who are referred to paediatric intensive care. The majority of complications may be anticipated and prevented resulting in improved management at DGH.

Stabilisation and Transport of the Critically Ill Child

Since the Department of Health Report ‘Paediatric Intensive Care: A framework for the future’ in 1997, paediatric intensive care services have been centralised and 24-hour retrieval services developed. However, all hospitals admitting critically ill children must be able to resuscitate and stabilise prior to retrieval, and occasionally undertake the ‘time-critical’ transfers themselves. This article reviews the clinical and organisational skills involved in the retrieval process, and also suggests ways in which knowledge and skills can be maintained.

Real-life use of vasopressors and inotropes in cardiogenic shock-observation is necessarily 'theory-laden'

We commend the attempt of Tarvasmaki et al. [1] to identify the mortality risk associated with individual vaso-active agents used in cardiogenic shock. However, despite their rigorous statistical analysis, we recommend caution in interpreting these results. Propensity score matching accounts for prior bias in the choice of vaso-active agents, but this choice of agent is often deeply engrained in individual clinician dogma which even propensity score matching may not uncover.

P07 Paediatric Diabetic Ketoacidosis Management Prior to Referral to a Paediatric Intensive Care Retrieval Service

Background Diabetic ketoacidosis (DKA) is the leading cause of morbidity and mortality in children with type 1 diabetes mellitus. Mortality is predominantly related to the occurrence of cerebral oedema. Management guidelines aim to minimise the risk by producing slow correction of the metabolic abnormalities. We audited the initial management of children in DKA at referring hospitals prior to referral to a paediatric intensive care retrieval service for advice and/or retrieval. Methods Data was retrospectively collected on all children in DKA referred to a regional paediatric intensive care retrieval service between 1.4.09 and 31.3.12. Management at referring hospitals was compared to UK guidelines (BSPED 2009). Results There were 121 episodes of DKA in 115 patients (median age 12.5 (0.7–16.4) years, 45% male). In 72 (60%) cases, DKA was the initial presentation of diabetes. Mean(SD) initial pH was 6.97 (0.11). In 29 (24%) cases, osmotherapy was given because of concerns about cerebral oedema. 34 (28%) cases were retrieved to a paediatric intensive care unit. 115 (95%) cases received fluid boluses as initial resuscitation (mean 22ml/kg). 17 (14%) received more than the recommended maximum of 30ml/kg (40ml/kg n = 11, 50ml/kg n = 4, 60ml/kg n = 2). Median estimated degree of dehydration was 8% (0–10%). 25 (21%) cases were estimated to be 10% dehydrated (recommended maximum 8%). Deficit was corrected over 48 hours in all cases. Fluid calculations were correct in 39/63 (62%) cases. The commonest reasons for error were failure to subtract initial fluid boluses and inaccurate maintenance calculation. Potassium replacement was given in 76% cases. Bicarbonate (not recommended) was given in 4 (3.3%) cases. 4 patients received an initial insulin bolus (not recommended). The insulin infusion rate was <0.05 units/kg/h in 2 cases, 0.05 units/kg/h in 30 cases and 0.1units/kg/h (recommended) in 80 (66%) cases. Insulin had not yet been commenced in the remaining 9 cases. Conclusion Despite the existence of clear guidelines, a significant proportion of children with severe DKA received excessive fluid resuscitation, inappropriately/inaccurately calculated ongoing fluid replacement and lower-than-recommended insulin infusion rates. These findings highlight areas that need ongoing education to improve patient care.