Shekhar T. Venkataraman

Unexpected Increased Mortality After Implementation of a Commercially Sold Computerized Physician Order Entry System

Objective. In response to the landmark 1999 report by the Institute of Medicine and safety initiatives promoted by the Leapfrog Group, our institution implemented a commercially sold computerized physician order entry (CPOE) system in an effort to reduce medical errors and mortality. We sought to test the hypothesis that CPOE implementation results in reduced mortality among children who are transported for specialized care. Methods. Demographic, clinical, and mortality data were collected of all children who were admitted via interfacility transport to our regional, academic, tertiary-care level children’s hospital during an 18-month period. A commercially sold CPOE program that operated within the framework of a general, medical-surgical clinical application platform was rapidly implemented hospital-wide over 6 days during this period. Retrospective analyses of pre-CPOE and post-CPOE implementation time periods (13 months before and 5 months after CPOE implementation) were subsequently performed. Results. Among 1942 children who were referred and admitted for specialized care during the study period, 75 died, accounting for an overall mortality rate of 3.86%. Univariate analysis revealed that mortality rate significantly increased from 2.80% (39 of 1394) before CPOE implementation to 6.57% (36 of 548) after CPOE implementation. Multivariate analysis revealed that CPOE remained independently associated with increased odds of mortality (odds ratio: 3.28; 95% confidence interval: 1.94–5.55) after adjustment for other mortality covariables. Conclusions. We have observed an unexpected increase in mortality coincident with CPOE implementation. Although CPOE technology holds great promise as a tool to reduce human error during health care delivery, our unanticipated finding suggests that when implementing CPOE systems, institutions should continue to evaluate mortality effects, in addition to medication error rates, for children who are dependent on time-sensitive therapies.

Predictors of extubation success and failure in mechanically ventilated infants and children.

OBJECTIVE To predict extubation success and failure in mechanically ventilated infants and children using bedside measures of respiratory function. DESIGN Prospective collection of data. SETTING A university-affiliated childrens hospital with a 51-bed critical care unit. PATIENTS All infants and children who were mechanically ventilated for at least 24 hrs, except neonates < or = 37 wks gestation and patients with neuromuscular disease. INTERVENTIONS Bedside measurements of cardiorespiratory function were obtained immediately before extubation. MEASUREMENTS AND MAIN RESULTS Extubation failure was defined as reintubation within 48 hrs of extubation in the absence of upper airway obstruction. Failure rates were calculated for different ranges (selected a priori) of preextubation measures of breathing effort, ventilatory support, respiratory mechanics, central inspiratory drive, and integrated indices useful in adults. Effort of spontaneous breathing was assessed by the respiratory rate standardized to age, the presence of retractions and paradoxical breathing, inspiratory pressure, maximal negative inspiratory pressure (maximal negative inspiratory pressure), inspiratory pressure/maximal negative inspiratory pressure ratio, and tidal volume indexed to body weight of a spontaneous breath. Ventilatory support was measured by the fraction of inspired oxygen (F10(2)), mean airway pressure, oxygenation index, and the fraction of total minute ventilation provided by the ventilator. Respiratory mechanics were assessed by determination of peak ventilatory inspiratory pressure and dynamic compliance. Central inspiratory drive was assessed by mean inspiratory flow. Frequency to tidal volume ratio and the compliance, rate, oxygenation, and pressure indexed to body weight, the integrated indices useful in predicting extubation failure in adults, were also calculated. Thirty-four of the 208 patients who were studied were reintubated for an overall failure rate of 16.3% (95% confidence interval 11.3% to 21.4%). The reasons for reintubation were poor effort (n = 8), excessive effort (n = 14), altered mental status or absent airway reflexes (n = 2), cardiovascular instability (n = 3), inadequate oxygenation (n = 3), respiratory acidosis (n = 3), and undocumented (n = 1). Extubation failure increased significantly with decreasing tidal volume indexed to body weight of a spontaneous breath, increasing F10(2), increasing mean airway pressure, increasing oxygenation index, increasing fraction of total minute ventilation provided by the ventilator, increasing peak ventilatory inspiratory pressure, or decreasing mean inspiratory flow (p < .05). Dynamic compliance showed a trend of increasing failure rate with decreasing dynamic compliance but did not reach statistical significance (p = .116). Respiratory rate standardized to age, inspiratory pressure, maximal negative inspiratory pressure, inspiratory pressure/maximal negative inspiratory pressure ratio, frequency to tidal volume ratio, and compliance, rate, oxygenation, and pressure did not show any trend in failure rate with increasing or decreasing values. Threshold values that defined a low risk (< or = 10%) and a high risk (> or = 25%) of extubation failure could be determined for tidal volume indexed to body weight of a spontaneous breath, F10(2), mean airway pressure, oxygenation index, fraction of total minute ventilation provided by the ventilator, peak ventilatory inspiratory pressure, dynamic compliance, and mean inspiratory flow. Neither a low nor a high risk of failure could be defined for frequency to tidal volume ratio or the compliance, rate, oxygenation, and pressure (CROP) index. CONCLUSIONS Bedside measurements of respiratory function can predict extubation success and failure in infants and children. Both a low risk and a high risk of failure can be determined using these measures. Integrated indices useful in adults do not reliably predict extubation success or failure in

Energy expenditure in critically ill children

Objectives: To measure energy expenditure in critically ill children and compare it with the energy expenditure predicted by recommended formulas, and relate the measured energy expenditure to nutritional and clinical indices. Design: A prospective, clinical study. Setting: Tertiary care pediatric intensive care unit in a university childrens hospital. Patients: A total of 37 patients with critical illness who were mechanically ventilated for ≥24 hrs were studied. Interventions: None. Measurements and Main Results: Chronic protein‐energy malnutrition (CPEM) and acute protein‐energy malnutrition were defined by the Waterlows stages and fat and protein stores were classified as defined by Frisancho, Ryan, and Martinez. Severity of illness was assessed by the Pediatric Risk of Mortality Score, the Therapeutic Intervention Scoring System, and indices of organ failure. Oxygen consumption, carbon dioxide production, and the respiratory quotient were measured by indirect calorimetry, and energy expenditure (MEE) was calculated using the modified Weir formula. Resting energy expenditure (PBMR), predicted energy expenditure, and caloric intake were calculated using recommended formulas. A total of 77 measurements were made in 37 children. MEE was significantly lower than PBMR as estimated by all equations except the Talbot equations. MEE was significantly lower than predicted energy expenditure and the recommended daily allowances. On the first day, the MEE/PBMR ratio was <0.9 in 56.8%, 0.9‐1.1 in 21.6%, and >1.1 in 21.6% of patients. MEE did not differ significantly among disease groups or between medical and surgical patients. There was no difference in MEE with or without neuromuscular blockade. MEE was lower in the presence of multiple organ system failure (MOSF) (1019 + 166 kcal/m2 without MOSF vs. 862 + 241 with MOSF; p = .025). A total of 21% had CPEM and 8.1% had acute protein‐energy malnutrition. Multivariate stepwise regression analysis showed that the protein intake, midarm muscle area, midarm fat area, the use of vasoactive agents, and sedation correlated with MEE (p < .05). With CPEM, MEE was correlated to the severity of illness (p < .05). Patients at risk for protein stores depletion (midarm muscle areas 1 and 2) had a higher incidence of MOSF compared with nutritionally normal children (p < .05), whereas patients with fat stores depletion (midarm fat area 2) had a higher probability of death (50% vs. 6%, respectively). Conclusions: Recommended daily allowances and energy expenditure predicted by using a stress‐related correction to the resting energy expenditure grossly overestimate MEE. MEE is close to PBMR and in many patients, it is lower than PBMR. MEE that is lower than PBMR is associated with a higher morbidity. Nutritional repletion should thus be based on MEE to avoid the problems of over‐ or underfeeding.

Weaning and extubation readiness in pediatric patients.

Objective: A systematic review of weaning and extubation for pediatric patients on mechanical ventilation. Data Selection: Pediatric and adult literature, English language. Study Selection: Invited review. Data Sources: Literature review using National Library of Medicine PubMed from January 1972 until April 2008, earlier cross-referenced article citations, the Cochrane Database of Systematic Reviews, and the Internet. Conclusions: Despite the importance of minimizing time on mechanical ventilation, only limited guidance on weaning and extubation is available from the pediatric literature. A significant proportion of patients being evaluated for weaning are actually ready for extubation, suggesting that weaning is often not considered early enough in the course of ventilation. Indications for extubation are even less clear, although a trial of spontaneous breathing would seem a prerequisite. Several indices have been developed in an attempt to predict weaning and extubation success but the available literature would suggest they offer no improvement over clinical judgment. Extubation failure rates range from 2% to 20% and bear little relationship to the duration of mechanical ventilation. Upper airway obstruction is the single most common cause of extubation failure. A reliable method of assessing readiness for weaning and predicting extubation success is not evident from the pediatric literature.

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% con fidence 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 catheteriza tions. 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 dura tion 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 compli cations 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 cathe terization in infants and children are safe with an expected high success rate and acceptably low complication rates.

Intrahospital transport of critically ill pediatric patients

OBJECTIVES To determine the frequency of adverse events during intrahospital transport; to determine the requirement of therapeutic interventions during transport; to test the hypothesis that adverse events that occur during intrahospital transport are due to the transport process itself; and to determine the factors that predict the occurrence of adverse events and the requirement of major therapeutic interventions during transport. DESIGN A two-phase study in which data were prospectively collected. In phase I, we examined the occurrence rate of adverse events, the requirement for therapeutic interventions, and the factors that predicted adverse events and the requirement of therapeutic interventions. In phase II, we tested the hypothesis that adverse events during transport were due to the transport process itself. SETTING A 250-bed university childrens hospital with a 50-bed intensive care unit (ICU). PATIENTS Phase I of the study consisted of one hundred and eighty intrahospital transports in 139 patients. These transports included patients who were transferred: a) to the ICU from the operating room, emergency department, or the general ward; b) from the ICU to the operating room; and c) from the ICU for diagnostic or therapeutic procedures. Phase II of the study consisted of 89 transports in 85 patients. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS Vital signs and oxygen saturation were measured before and during transport. In phase I, there were no adverse events in 23.9% of transports. There was a significant change in at least one physiologic variable in 71.7% of transports, and at least one equipment-related mishap in 10% of transports. At least one major intervention was performed in 13.9% of transports in response to physiologic deterioration or an equipment-related mishap. There were no arrests or deaths during transport. The requirement for a major procedure was 34.4% in mechanically ventilated patients vs. 9.5% in nonventilated patients. Logistic regression analysis showed that both pretransport Therapeutic Intervention Scoring System and the duration of transport were significantly associated with the requirement of a major intervention and physiologic deterioration, while only the duration of transport was associated with an equipment-related event. The age of the patient and the number of escorts accompanying the transport did not affect the frequency of adverse events. Before transport in phase II study patients, no patient became hypothermic, the changes in physiologic variables were always < 20%, and there was no change > or = 5% in oxygen saturation. Hypothermia occurred in 11.2% of transports. A > or = 20% change in heart rate (15.7%), blood pressure (21.3%), and respiratory rate (23.6%) was seen only during transport. A > 5% change in oxygen saturation (5.6%) was seen only during transport. CONCLUSIONS Serious physiologic deterioration occurs during intrahospital transport of critically ill children. Severity of illness and the duration of transport are associated with the occurrence of adverse events during transport. The team composition and equipment required on transport must be commensurate with the pretransport severity of illness and the anticipated duration of transport.

Validation of predictors of extubation success and failure in mechanically ventilated infants and children

ObjectiveTo validate predictors of extubation success and failure in mechanically ventilated infants and children by using bedside measures of respiratory function. DesignProspective, descriptive study. SettingA university-affiliated children’s hospital with a 51-bed critical care area. PatientsAll infants and children who were mechanically ventilated for ≥24 hrs except neonates ≤37 wks gestation and patients with neuromuscular disease. InterventionsNone. Measurements and MethodsExtubation failure was defined as reintubation within 48 hrs of extubation in the absence of upper airway obstruction. Failure rates were calculated for different ranges (selected a priori) of preextubation measures of breathing effort, ventilator support, respiratory mechanics, central inspiratory drive, and integrated indices useful in adults. Effort of spontaneous breathing was assessed by the respiratory rate standardized to age, the presence of retractions and paradoxic breathing, inspiratory pressure, maximal negative inspiratory pressure, ratio of inspiratory pressure to maximal negative inspiratory pressure, and tidal volume indexed to body weight of a spontaneous breath. Ventilator support was measured by Fio2, mean airway pressure, oxygenation index, and the fraction of total minute ventilation provided by the ventilator. Respiratory mechanics was assessed by peak ventilatory inspiratory pressure and dynamic compliance. Central inspiratory drive was assessed by mean inspiratory flow. Frequency to tidal volume ratio and the CROP (compliance, rate, oxygenation, and pressure) indexed to body weight, the integrated indices useful in predicting extubation failure in adults, were also calculated. A regression test for a linear trend in proportions was performed with preselected ranges and the corresponding failure rates. The failure rates from this study (validation group) were compared to those published previously (prediction group) by the chi-square test for proportions. The distribution of categorical variables between groups was analyzed by using the chi-square test or the Fisher’s exact test, and p < .05 was considered significant. Main ResultsThe study involved 312 patients. There were no differences in any of the clinical characteristics between the prediction and validation groups. The reasons for reintubation were similar in both groups. Preextubation data were also similar between the two groups. There were no differences between the prediction and the validation groups in failure rates with different ranges. There were no differences in the failure rates for any of the cutoff values for peak ventilatory inspiratory pressure, mean airway pressure, Fio2, oxygenation index, dynamic compliance, tidal volume indexed to body weight of a spontaneous breath, fraction of total minute ventilation provided by the ventilator, and mean inspiratory flow. ConclusionsBedside measures of respiratory function can predict extubation success and failure in infants and children. Both a low risk and a high risk of failure can be determined by using these measures. Integrated indices useful in adults do not reliably predict extubation success or failure in infants and children. Our study validates our previously published study.

Helium/oxygen-driven albuterol nebulization in the treatment of children with moderate to severe asthma exacerbations: a randomized, controlled trial.

Background. Helium and oxygen mixtures (heliox) increase both pulmonary aerosol delivery and gas delivery relative to oxygen. We aimed to compare the effectiveness of a 70%:30% helium/oxygen (heliox)–driven continuous aerosol delivery versus 100% oxygen-driven delivery in the treatment of asthmatic children with moderate to severe exacerbations. Methods. We enrolled 30 children aged 2 to 18 years who presented to an urban, pediatric emergency department (ED) with moderate to severe asthma as defined by a pulmonary index (PI) score of ≥8. PI scores can range from 0 to 15. In this randomized, controlled, single-blind trial conducted in a convenience sample of children, all patients in the trial received an initial nebulized albuterol (5 mg) treatment driven by 100% oxygen and a dose of oral prednisone or prednisolone. Subsequently, patients were randomly assigned to receive continuously nebulized albuterol (15 mg/hour) delivered by either heliox or oxygen using a nonrebreathing face mask. The primary outcome measure was degree of improvement as assessed in blinded video-recorded PI scores over 240 minutes (at 30-minute intervals for the first 3 hours) or until ED discharge (if <240 minutes). Results. The mean change in PI score from baseline to 240 minutes or ED discharge was 6.67 for the heliox group compared with 3.33 for the oxygen group. Eleven (73%) patients in the heliox group were discharged from the hospital in <12 hours compared with 5 (33%) patients in the conventional group. Conclusion. Continuously nebulized albuterol delivered by heliox was associated with a greater degree of clinical improvement compared with that delivered by oxygen among children with moderate to severe asthma exacerbations.

Percutaneous infraclavicular subclavian vein catheterization in critically ill infants and children

The safety and risks of percutaneous infraclavicular subclavian vein catheterization, when performed by nonsurgical staff, were studied prospectively in 100 consecutive patients. The overall success rate was 92% (with one attempt, 45%; with two attempts, 85%). The procedure was performed under emergency conditions in 35% of the patients, with a success rate of 88.6%. The success rate was significantly lower in younger patients. Hemodynamic status, respiratory status, and level of expertise of the individual performing catheterization did not affect success rate. Most of the failures (six of eight) were related to presumed thrombosis from prior cannulation of the superior vena cava. Mean duration of catheterization was 7.5 +/- 5.8 days (+/- SD). Minor complications (n = 24) included hematomas, minor bleeding from subclavian artery puncture, and transient premature ventricular ectopic beats. Major complications (n = 6) were pneumothoraces (n = 4) and catheter-related infection (n = 2). The number of attempts made to catheterize the vessel and the level of expertise of the operator had the greatest effect on complication rates. No mortality was associated with this procedure. We have found percutaneous infraclavicular subclavian vein catheterization to be a rapid alternative to surgical cutdown for venous access during cardiopulmonary resuscitation. Pediatric residents can be trained, under direct supervision, to perform this procedure with a high success rate and a low complication rate.

The use of drugs in emergency airway management in pediatric trauma

Most patients who require emergency airway control receive drugs to induce rapidly sufficient anesthesia for direct laryngoscopy and endotracheal intubation, but there are no protocols that outline the use of specific drugs in general use. Drugs should safely and rapidly produce (1) unconsciousness; (2) paralysis; and (3) blunt intracranial pressure (ICP) responses to airway procedures. Consequences to be considered include increased ICP, hemorrhagic shock, and a full stomach. To refine the use of drugs used for airway procedures in pediatric trauma patients, the authors reviewed all cases of emergency endotracheal intubation over a recent 12-month period (1) to see whether medications used met the goals of producing unconsciousness and paralysis and blunting ICP responses were met safely; and (2) to identify potential drug-related complications. From July 1, 1990, to June 30, 1991, 60 of 791 children (7.6%) required endotracheal intubation at the scene of injury, at the referring hospital, or in our emergency department (15; 25%). Ten patients died (16.7%). Three fourths were younger than 9 years of age. All except one suffered blunt injuries. Nearly all (95%) suffered head injuries, isolated in 39 of 57 (68.4%) and combined with injuries in other regions in 18 (31.6%). Fifteen patients were in apnea (25%); seven were both apneic and pulseless. Three fourths (45 of 60) had diminished levels of consciousness; one fourth (15 of 60) were awake. Immediate endotracheal intubation proceeded appropriately without drugs in all seven patients in cardiopulmonary arrest. Only eight of the remaining 53 patients (15.1%) received an optimal medication regimen. Many patients with head injury were inadequately protected against increases in ICP. Thiopental, an effective anesthetic agent that effectively lowers intracranial pressure, was not used in 25 of 35 stable patients with isolated head injury (71.4%). Intravenous lidocaine was not used in 38 of 50 head-injured patients in whom it would have been an appropriate adjunct to control increases in ICP (76%). Eight patients received paralyzing agents alone, without sedatives or narcotics. Medications were thought inadequate to relieve the pain and discomfort of laryngoscopy and endotracheal intubation in 32 of the 53 patients who should have received them (60.4%). No paralyzing agents were used in 36 of the 53 instances where it would have been appropriate (67.9%). In two of 11 instances (18.3%) where succinylcholine was administered, no prior nondepolarizing agent was used. Complications of a full stomach at the time of emergency endotracheal intubation became evident in 10 patients (16.7%) who vomited during procedures to control the airway. Two patients (3.3%) aspirated.(ABSTRACT TRUNCATED AT 400 WORDS)