A Minimal Opioid Postoperative Management Protocol in Congenital Cardiac Surgery: Safe and Effective

There is evidence that reducing opioid exposure in children undergoing cardiac surgery may enhance postoperative recovery. We aimed to describe a minimal opioid postoperative management protocol in children undergoing cardiac surgery and our early outcomes with this strategy. We reviewed the medical records of children (6 months-18 years) who underwent elective cardiac surgery through a median sternotomy with cardiopulmonary bypass at our institution between 2016 and 2018. All patients were managed postoperatively using a standardized protocol. 101 children (median age 5 years) were included and 85% were extubated in the operating room. Although most patients (96%) received opioids postoperatively, opioid requirements decreased steadily over time, with 88%, 58%, and 18% of children receiving opioids on postoperative day 1, 2, and 3, respectively; 41% received no opioids after postoperative day 1. The median cumulative opioid exposure was 0.25 morphine milligram equivalents per kg (interquartile range, 0.10-0.75). Greater than mild pain was rare (<10%) at each time point. The rates of operative mortality and major complication were 0% and 3%, respectively. The median postoperative length of stay was 3 days, and 13% required readmission within 30 days. Age, cardiopulmonary bypass time, and number of benzodiazepine doses were independently associated with cumulative opioid exposure. Any complication, chest tube time, and higher STAT Category were independently associated with prolonged postoperative length of stay. A minimal opioid postoperative management protocol can be safe and effective in children undergoing cardiac surgery. Future prospective studies are needed to determine optimal practice and patient selection.

Ultrasound diaphragmatic manual and semi-automated motion measurements: Application in simulated and in vivo data of critically ill subjects

BACKGROUND AND OBJECTIVE

Ultrasound diaphragmatic muscle motion characteristics may provide useful information about normal or abnormal diaphragmatic function and indicate diaphragmatic weakness, or paralysis. In the present work we propose and evaluate an integrated semi-automated analysis system for the quantitative analysis of ultrasonic motion from ultrasound diaphragmatic videos.

METHODS

The proposed system was evaluated in simulated videos and in 13 patients, four of whom patients were mechanically ventilated. The major steps of the methodology were as follows: video normalization, despeckle filtering, generation of an M-Mode image, snakes segmentation, and motion measurements.

RESULTS

The following manual (-/) vs semi-automated (/-), (median±IQR) measurements, which are routinely carried out by the experts, for assessing the severity of the disease, were computed. For the simulated videos the diaphragmatic excursion was 1.80±0.00 cm / 1.76±0.03 cm. For all the real ultrasound videos investigated in this study the following measurements were computed: (i) diaphragmatic excursion: 0.84±0.15 cm / 0.83±0.14 cm, (ii) inspiration time (T_insp): 0.71±0.18 sec / 0.70±0.15 sec, (iii) total breathing time for one cycle (T_tot): 1.71±0.37 sec / 1.67±0.37 sec, (iv) diaphragmatic curve slope: 1.29±0.36 cm/sec / 1.27±0.36 cm/sec, and (v) relaxation rate (RR): 0.82±0.17 cm/sec / 0.82±0.18 cm/sec.

CONCLUSIONS

Manual and semi-automated measurements were very close with non-statistical significant differences and strong correlations between them. It is anticipated that the proposed system might be useful in the clinical practice in the assessment and follow up of patients with diaphragmatic weakness or paralysis and aid in the separation of normal and abnormal diaphragmatic motion. Further validation and additional experimentation in a larger sample of videos and different patient groups is required.

Validation of a national algorithm for diabetes screening

Background

The continuing upward trend in diabetes diagnosis across the world has led governments to adopt new treatment programs. According to the International Federation for Diabetes (2017) Europe and in its Member States spent from 10% to 20% of healthcare costs, for diabetes. The purpose of this study is to assess the feasibility of an algorithm to identify both the regulatory needs of diabetic individuals and to screen for undiagnosed individuals in the community.

Methods

The population sample consisted of 2100 people. The survey was conducted in two phases over the period 2017-2018. In the first phase we identified the 188 already diagnosed people with diabetes who were asked to answer a questionnaire comparing their current standard of care to NICE indicators. In the second phase, the remaining 1912 non-diabetic patients were asked to answer the Findrisk questionnaire. Those who were classified as high risk and very high risk were selected and referred to a clinical laboratory where they were subjected to a glucose curve to detect any diagnosis.

Results

The diabetes prevalence at the onset of the study was 9% (188/2100 people). Fifty-two new incidents were diagnosed. Thirty-six new cases were diagnosed by randomized glucose values after triple check and symptomatic diabetes symptoms consistent with the World Health Organization’s recommendations on diabetes diagnosis. Sixteen new cases were diagnosed via OGTT. The prevalence of diabetes at the end of the survey reached 11.4% (240/2,100 people)..

Conclusions

It has been found that one person in every forty in the general population suffers from diabetes without been yet diagnosed. Deviations from international diabetes standards have been observed. A new diabetes strategy should be implemented in the future, allowing the catholic implementation of the Findrisk Diabetes Prevention tool every ten years.

Key messages

Despite existing guidelines and recommendations, very few diabetic patients fulfill NICE follow up criteria. FINDRISK and OGTT can be used as part of a cost-effective national diabetes screening algorithm.

Measurement of ultrasonic diaphragmatic motion

The motion characteristics of the diaphragmatic muscle may provide useful information about normal and abnormal diaphragmatic function and indicate diaphragmatic weakness. The objective of this paper was to introduce a simple system for the quantitative analysis of ultrasonic diaphragmatic motion. The measurements routinely carried out by the experts were computed and these include: (i) excursion, (ii) inspiration time (Tinsp) and (iii) cycle duration (Ttot). The system was evaluated on four simulated videos and one real video. Manual and automated measurements were very close. Further work in a larger number of videos is needed for validating the proposed method.

A phase II/III, multicenter, safety, efficacy, and pharmacokinetic study of dexmedetomidine in preterm and term neonates

OBJECTIVE

To investigate the safety, efficacy, and pharmacokinetic profile of dexmedetomidine in preterm and full-term neonates ≥ 28 to ≤ 44 weeks gestational age.

STUDY DESIGN

Forty-two intubated, mechanically ventilated patients (n = 42) were grouped by gestational age into group I (n = 18), ≥ 28 to <36 weeks, and group II (n = 24), ≥ 36 to ≤ 44 weeks. Within each age group, there were 3 escalating dose levels, including a loading dose (LD, μg/kg) followed by a maintenance dose (MD, μg · kg(-1) · h(-1)) for 6-24 hours: level 1, 0.05 LD/MD; level 2, 0.1 LD/MD; and level 3, 0.2 LD/MD. The primary endpoint was the number of patients requiring sedation as determined by the Neonatal Pain, Agitation, Sedation Scale.

RESULTS

During dexmedetomidine infusion, 5% of Neonatal Pain, Agitation, Sedation Scale scores were >3, indicating agitation/pain, with 4 patients (10%) requiring more sedation and 17 (40%) requiring more analgesia. Though there was significant variability in pharmacokinetic variables, group I appeared to have lower weight-adjusted plasma clearance (0.3 vs 0.9 L · h(-1) · kg(-1)) and increased elimination half-life (7.6 vs 3.2 hours) compared with group II. Fifty-six adverse events (AEs) were reported in 26 patients (62%); only 3 AEs (5%) were related to dexmedetomidine. There were no serious AEs and no AEs or hemodynamic changes requiring dexmedetomidine discontinuation.

CONCLUSION

Dexmedetomidine is effective for sedating preterm and full-term neonates and is well-tolerated without significant AEs. Preterm neonates had decreased plasma clearance and longer elimination half-life.

Total cavopulmonary connection in patients with apicocaval juxtaposition: optimal conduit route using preoperative angiogram and flow simulation

OBJECTIVES

Single ventricle with apicocaval juxtaposition (ACJ) is a rare, complex anomaly, in which the optimal position of the conduit for completion of total cavopulmonary connection (TCPC) is still controversial. The purpose of this study was to identify a preoperative method for optimal conduit position using the IVC anatomy and computational fluid dynamics (CFD).

METHODS

Twenty-four patients with ACJ (5.3 ± 5.7 years) who underwent TCPC were enrolled. A conduit was placed ipsilateral to the cardiac apex in each of 11 patients, of which 9 were intra-atrial and 2 extracardiac (group A) and, in a further 13 patients, extracardiac on the contralateral side (group B). As control, 10 patients with tricuspid atresia were also enrolled (group C). The location of the IVC in relation to the spine was evaluated from the frontal view of preoperative angiogram, using the following index: IVC-index = IVC width overlapping the vertebra/width of the vertebra × 100%. Energy loss was calculated by CFD simulation.

RESULTS

IVC-index of group B was larger than groups A and C (45 ± 26 vs. 20 ± 21 and 28 ± 19%, P = 0.03). Postoperative catheterizations showed that, due to its curvature, conduit length in group B was significantly longer than the others (65 ± 12 vs. 36 ± 14 and 44 ± 10 mm, P < 0.001), although there was no statistical difference in central venous pressure or cardiac output. CFD studies revealed less energy loss in group A conduits compared with group B (1.6 ± 0.3 vs. 3.6 ± 0.6 mW, P = 0.05), although this did not appear to be clinically significant. Moreover, CFD simulation showed significant energy loss within the Fontan circulation when the conduit was either compressed or kinked: 4.9 and 18.2 mW respectively.

CONCLUSIONS

In patients with ACJ, placement of a straighter and shorter conduit on the ventricular apical side provides better laminar blood flow with less energy loss. However, conduit compression and kinking are far more detrimental to the Fontan circulation. A preoperative IVC-index is pivotal for avoiding these factors and deciding the optimal conduit route.

Neurodevelopmental Outcomes after Pediatric Cardiac ECMO Support

PURPOSE

To characterize the neurodevelopmental outcomes and identify factors associated with poor outcomes in pediatric patients undergoing cardiac extracorporeal membrane oxygenation (ECMO).

METHODS

Five year retrospective review, including demographics, cardiac lesion, and surgical complexity, reason for ECMO, ECMO complications, and neurodevelopmental status at discharge and latest follow-up. Neurodevelopmental status was determined through the Pediatric Overall Performance Category and Pediatric Cerebral Performance Category Scales.

RESULTS

Overall ECMO survival was 73% at hospital discharge and 66% a t the latest follow-up. Most patients underwent cardiopulmonary resuscitation (CPR) (43%), and the majority (53%) had a significant disease complexity (Aristotle = 4). Complications occurred in 42% of the ECMO runs, of which 12% were intracranial injuries. At hospital discharge, 75% of patients had normal to mild disability, improving to 81% at 2 years follow-up. At hospital discharge, moderate to severe disability was associated with CPR, plasma exchange or intracranial insults. After discharge, 23% showed improvement in neurologic status and 4% showed deterioration. Cerebral infarction was the only parameter associated with deterioration at the later follow-up stage.

CONCLUSION

Extracorporeal membrane oxygenation was successfully used in children with cardiac disease with 73 and 66% short and long-term survival respectively. Majority of the survivors had normal to mild neurodevelopmental disability and a significant portion showed neurologic improvement by the latest follow-up. Nevertheless, despite the grossly favorable outcomes standardized comprehensive neuropsychological testing is of paramount importance in all these patients.

Short- and intermediate-term survival after extracorporeal membrane oxygenation in children with cardiac disease

OBJECTIVES

In children with cardiac disease, common indications for extracorporeal membrane oxygenation (ECMO) include refractory cardiopulmonary resuscitation (E-CPR), failure to separate from cardiopulmonary bypass (OR-ECMO), and low cardiac output syndrome (LCOS-ECMO). Despite established acceptance, ECMO outcomes are suboptimal with a survival between 38% and 55%. We evaluated factors associated with significantly increased survival in cardiac patients requiring ECMO.

METHODS

We conducted a retrospective investigation of consecutive patients undergoing ECMO between 2006 and 2010. Demographic, pre-ECMO, ECMO, and post-ECMO parameters were analyzed. Neurologic outcomes were assessed with the pediatric overall performance category scale at the latest follow-up.

RESULTS

There were 3524 admissions, 95 (3%) of which necessitated ECMO; 40 (42%) E-CPR, 31 (33%) OR-ECMO, and 24 (25%) LCOS-ECMO. The overall hospital survival was 73%. The within-groups hospital survival was 75% in E-CPR, 77% OR-ECMO and 62% LCOS-ECMO. In the multivariable logistic regression analysis, chromosomal anomalies (odds ratio [OR], 8; 95% confidence interval [CI], 2-35), single ventricle (OR ,6; 95% CI, 3-33), multiple ECMO runs (OR, 15; 95% CI, 4-42), higher 24-hour ECMO flows (OR, 8; 95% CI, 4-22), decreased lung compliance (OR, 5; 95% CI, 2-16), and need for plasma exchange (OR, 5; 95% CI, 3-18) were all significant factors associated with mortality. From the univariate analysis, a common parameter associated with mortality within all groups was intracranial hemorrhage. At 1.9 years (0.9, 2.9) of follow-up, 66% were still alive, and 89% of survivors had normal function or only mild neurodevelopmental disability.

CONCLUSIONS

ECMO was successfully used in children with cardiac disease with 73% and 66% short- and intermediate-term survival, respectively. The majority of the survivors had normal function or only a minimal neurodevelopmental deficit.

Dexmedetomidine: therapeutic use for the termination of reentrant supraventricular tachycardia

OBJECTIVES

The current drug of choice for reentrant supraventricular tachycardia (SVT) is adenosine followed by verapamil or diltiazem. Although limitations and significant adverse events have been encountered over the years, an alternative effective and safe agent has not been available. Dexmedetomidine has recently been shown to have potential antiarrhythmic effects, and here we describe our experience in the acute termination of reentrant SVT.

DESIGN

Retrospective case series.

SETTING

Quaternary University Children's Hospital, Cardiac Intensive Care Unit.

PATIENTS

Patients who received dexmedetomidine for SVT in the past 5 years.

INTERVENTIONS

None.

OUTCOME MEASURES

SVT episodes terminated with dexmedetomidine were compared with episodes terminated with adenosine.

RESULTS

Fifteen patients, median age of 10 days (6-16), were given 27 doses of dexmedetomidine, mean dose 0.7 ± 0.3 mcg/kg, for a total of 27 episodes of SVT. Successful termination occurred in 26 episodes (96%) at a median time of 30 seconds (20-35). Duration of sinus pause was 0.6 ± 0.2 seconds, there was one episode of hypotension and no bradycardia and sedation lasted for 34 ± 8 minutes. Five patients received 27 doses of adenosine, with an overall successful cardioversion in 17 patients (63%) (P= .0017). Transient bradycardia and hypotension was seen in three patients (11%), agitation in 16 patients (59%), and broncospasm in one patient. Median sinus pause was 2.5 seconds (2-9) (P < .001).

CONCLUSIONS

Dexmedetomidine appears to have novel antiarrhythmic properties for the acute termination of reentrant SVT. Although adenosine is very effective, dexmedetomidine may prove to possess a more favorable therapeutic profile with increased effectiveness and fewer side effects.

Critical congenital heart disease--utility of routine screening for chromosomal and other extracardiac malformations

Objective.  Infants with critical congenital heart disease (CHD) can have genetic and other extracardiac malformations, which add to the short- and long-term risk of morbidity and perhaps mortality. We sought to examine our center's practice of screening for extracardiac anomalies and to determine the yield of these tests among specific cardiac diagnostic categories. Design.  Retrospective review of infants admitted to the cardiac intensive care unit with a new diagnosis of CHD. Subjects were categorized into six groups: septal defects (SD), conotruncal defects (CTD), single-ventricle physiology (SV), left-sided obstructive lesions (LSO), right-sided obstructive lesions (RSO), and "other" (anomalous pulmonary venous return, Ebstein's anomaly). Screening modalities included genetic testing (karyotype and fluorescent in situ hybridization for 22q11.2 deletion), renal ultrasound (RUS), and head ultrasound (HUS). Results.  One hundred forty-one patients were identified. The incidence of cardiac anomalies was: CTD (36%), SD (18%), SV (18%), LSO (14%), RSO (3%), and "other" (8%). Overall 14% had an abnormal karyotype, 5% had a deletion for 22q11.2, 28% had an abnormal RUS and 22% had abnormal HUS. Patients in SD and SV had the highest incidence of abnormal karyotype (36% and 17%); 22q11.2 deletion was present only in CTD and LSO groups (9% and 7%, respectively); abnormal RUS and HUS were seen relatively uniformly in all categories. Premature infants had significantly higher incidence of renal 43% vs. 24%, and intracranial abnormalities 46% vs. 16%. Conclusion.  Infants with critical CHD and particularly premature infants have high incidence of genetic and other extracardiac anomalies. Universal screening for these abnormalities with ultrasonographic and genetic testing maybe warranted because early detection could impact short and long-term outcomes.

Perioperative use of dexmedetomidine is associated with decreased incidence of ventricular and supraventricular tachyarrhythmias after congenital cardiac operations

BACKGROUND

Postoperative tachyarrhythmias remain a common complication after congenital cardiac operations. Dexmedetomidine (DEX), an α-2 adrenoreceptor agonist, can have a therapeutic role in supraventricular tachyarrhythmias for cardioversion to sinus rhythm or heart rate control. Whether routine perioperative use of DEX decreases the incidence of supraventricular and ventricular tachyarrhythmias was studied.

METHODS

In this prospective cohort study, 32 pediatric patients undergoing cardiothoracic operations received DEX and were compared with 20 control patients who did not receive DEX.

RESULTS

Dexmedetomidine was started after anesthesia induction and continued intraoperatively and postoperatively for 38±4 hours (mean dose, 0.76±0.04 μg/kg/h). Ten control patients and 2 DEX patients sustained 16 episodes of tachyarrhythmias (p=0.001), including a 25% vs 0% (p=0.01) incidence of ventricular tachycardia and 25% vs 6% (p=0.05) of supraventricular arrhythmias in the control and DEX group, respectively. Transient complete heart block occurred in 2 control patients and in 1 DEX patient. Control patients had a higher heart rate (141±5 vs 127±3 beats/min, p=0.03), more sinus tachycardia episodes (40% vs 6%; p=0.008), required more antihypertensive drugs with nitroprusside (20±7 vs 4±1 μg/kg; p=0.004) and nicardipine (13±5 vs 2±1 μg/kg; p=0.02), and required more fentanyl (39±8 vs 19±3 μg/kg; p=0.005).

CONCLUSIONS

Perioperative use of dexmedetomidine is associated with a significantly decreased incidence of ventricular and supraventricular tachyarrhythmias, without significant adverse effects.

Kounis syndrome or allergic coronary vasospasm in a two-year-old

Kounis syndrome is coronary vasospasm because of mast cell degranulation in the context of an allergic reaction. The syndrome has known associations with several drugs used during anesthesia, including rocuronium and isoflurane. In this case report, we discuss a 2-year-old patient who developed signs and symptoms of an acute coronary syndrome soon after anesthesia for atrial septal defect repair. A diagnostic angiography after the episode revealed diffusely small coronary arteries. Subsequent angiography after clinical improvement showed essentially normal coronary anatomy. We report the clinical course of this patient and postulate that Kounis syndrome was the explanation for his transient coronary vasospasm. To date, this is the youngest known patient with reported Kounis syndrome.

Acute hemodynamic changes after rapid intravenous bolus dosing of dexmedetomidine in pediatric heart transplant patients undergoing routine cardiac catheterization

BACKGROUND

Dexmedetomidine is a highly selective α(2)-adrenoceptor agonist with sedative, anxiolytic, and analgesic properties that has minimal effects on respiratory drive. Its sedative and hypotensive effects are mediated via central α(2A) and imidazoline type 1 receptors while activation of peripheral α(2B)-adrenoceptors result in an increase in arterial blood pressure and systemic vascular resistance. In this randomized, prospective, clinical study, we attempted to quantify the short-term hemodynamic effects resulting from a rapid i.v. bolus administration of dexmedetomidine in pediatric cardiac transplant patients.

METHODS

Twelve patients, aged 10 years or younger, weighing ≤40 kg, presenting for routine surveillance of right and left heart cardiac catheterization after cardiac transplantation were enrolled. After an inhaled or i.v. induction, the tracheas were intubated and anesthesia was maintained with 1 minimum alveolar concentration of isoflurane in room air, fentanyl (1 μg/kg), and rocuronium (1 mg/kg). At the completion of the planned cardiac catheterization, 100% oxygen was administered. After recording a set of baseline values that included heart rate (HR), systolic blood pressure, diastolic blood pressure, central venous pressure, systolic pulmonary artery pressure, diastolic pulmonary artery pressure, pulmonary artery wedge pressure, and thermodilution-based cardiac output, a rapid i.v. dexmedetomidine bolus of either 0.25 or 0.5 μg/kg was administered over 5 seconds. The hemodynamic measurements were repeated at 1 minute and 5 minutes.

RESULTS

There were 6 patients in each group. Investigation suggested that systolic blood pressure, diastolic blood pressure, systolic pulmonary artery pressure, diastolic pulmonary artery pressure, pulmonary artery wedge pressure, and systemic vascular resistance all increased at 1 minute after rapid i.v. bolus for both doses and decreased significantly to near baseline for both doses by 5 minutes. The transient increase in pressures was more pronounced in the systemic system than in the pulmonary system. In the systemic system, there was a larger percent increase in the diastolic pressures than the systolic pressures. Cardiac output, central venous pressure, and pulmonary vascular resistance did not change significantly. HR decreased at 1 minute for both doses and was, within the 0.5 μg/kg group, the only hemodynamic variable still changed from baseline at the 5-minute time point.

CONCLUSION

Rapid i.v. bolus administration of dexmedetomidine in this small sample of children having undergone heart transplants was clinically well tolerated, although it resulted in a transient but significant increase in systemic and pulmonary pressure and a decrease in HR. In the systemic system, there is a larger percent increase in the diastolic pressures than the systolic pressures and, furthermore, these transient increases in pressures were more pronounced in the systemic system than in the pulmonary system.

Dexmedetomidine: sedation, analgesia and beyond

BACKGROUND

Dexmedetomidine is an alpha-2 adrenoreceptor agonist with sedative, analgesic and anxiolytic properties. Since its release in the US market in late 1999, it has gained remarkable attention in the adult, pediatric and geriatric populations, predominantly because of its minimal respiratory depression. However, beyond its well-known properties, dexmedetomidine has recently been investigated for its potential in many other clinical scenarios, including neuroprotection, cardioprotection and renoprotection, with promising results.

OBJECTIVE

This review provides an outline of the current use of dexmedetomidine in adult and pediatric populations in several clinical settings, including operating room, intensive care unit, postsurgical patients and patients who need sedation and/or analgesia for invasive and noninvasive procedures. Our objectives were to examine the most up-to-date clinical evidence, describe the magnitude of effects, and shed some light on potential future applications.

METHODS

Published, peer-reviewed studies, including preclinical data, were included in this review article.

RESULTS/CONCLUSIONS

Dexmedetomidine is a novel agent with a wide safety margin and excellent sedative and moderate analgesic properties. Though its broadest use is currently in surgical and nonsurgical intensive care unit patients, dexmedetomidine appears to have promising future applications in the areas of neuroprotection, cardioprotection and renoprotection.

Use of dexmedetomidine in children after cardiac and thoracic surgery

OBJECTIVE

In this report, we describe our experience with the use of dexmedetomidine in spontaneously breathing as well as in mechanically ventilated patients, after congenital cardiac and thoracic surgery.

DESIGN

Retrospective case series.

SETTING

University hospital, pediatric cardiac intensive care unit.

PATIENTS

Thirty-three spontaneously breathing and five mechanically ventilated patients who received dexmedetomidine after cardiothoracic surgery.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Thirty-eight patients, age 8 +/- 1.1 yrs old and weight 29 +/- 3.8 kg, were included. Seven patients (18%) were <1 yr old. Dexmedetomidine was used as a primary sedative and analgesic agent, and when its effect was considered inadequate, despite incremental infusion doses, a rescue agent was administered. The initial dexmedetomidine infusion dose was 0.32 +/- 0.15 microg/kg/hr followed by an average infusion of 0.3 +/- 0.05 microg/kg/hr (range 0.1-0.75 microg/kg/hr). There was a trend toward higher dexmedetomidine infusion requirement in patients <1 yr old compared with older children, 0.4 +/- 0.13 vs. 0.29 +/- 0.17 microg/kg/hr (p = .06). Desired sedation and analgesia were achieved during 93% and 83% of the dexmedetomidine infusion, respectively. According to the intensive care unit sedation scale (score 0-3) and two pain scales (Numeric Visual Analog Scale and Face, Legs, Activity, Cry, and Consolability, score 0-10), the mean sedation score was 1.3 +/- 0.6 (mild sedation) and the mean pain score was 1.5 +/- 0.9 (mild pain). The most frequently rescue drugs administered were fentanyl, morphine, and midazolam. Overall, 49 rescue doses of sedatives/analgesics were given. Patients <1 yr old required more rescue boluses than older children, 22 boluses (3.19 +/- 0.8) vs. 27 boluses (0.8 +/- 0.2, p = .003). Throughout the dexmedetomidine infusion there was no significant change in the systolic and diastolic blood pressure trend. Six patients (15%) had documented hypotension. In three, hypotension resolved with decreasing the dexmedetomidine infusion dose whereas in the other three, hypotension resolved after discontinuing the infusion. Although there was a trend toward lower heart rates, this was not clinically significant. One patient had an episode of considerable bradycardia without hypotension, which resolved shortly after discontinuing the dexmedetomidine infusion. No significant changes in the arterial blood gases or respiratory rates were observed. There was no mortality, and the total intensive care unit length of stay was 19 +/- 2 hrs.

CONCLUSIONS

Our data suggest that dexmedetomidine is a well-tolerated and effective agent for both spontaneously breathing and mechanically ventilated patients following congenital cardiac and thoracic surgery.

Use of dexmedetomidine in a pediatric heart transplant patient

Dexmedetomidine is a new sedative and analgesic agent that has a unique property of lack of respiratory depression. We describe a pediatric case in which the use of dexmedetomidine enabled us to successfully extubate a 12-year-old heart transplant patient with acute pneumonia after several failed attempts with the use of more conventional sedation.

Giant aneurysm of the atrial septum associated with premature closure of foramen ovale

Premature closure or restriction of foramen ovale (PCFO) is a rare congenital anomaly that can lead to a wide spectrum of cardiac malformations. This spectrum of secondary malformations appears to depend on the gestational timing of closure of the foramen ovale and to the degree of restriction. Earlier in the gestation, closure of the foramen has been associated with severe hypoplasia of the left ventricle whereas later closure has been associated with right heart failure and rarely with the formation of an aneurysm of the atrial septum. We describe the case of a 1 day old infant in whom PCFO resulted in severe right heart failure in addition to the formation of a giant atrial septal aneurysm.

Is the National Health Service at the edge of chaos?

We used chaos and complexity theory to analyse waiting-list data (1998-2001) pertaining to over 20 000 National Health Service (NHS) patients from general surgical, orthopaedic and neurosurgical units across England. Plots of frequency versus quarter-to-quarter change in waiting times revealed a power relation which seems independent of surgical specialty and hospital location. One interpretation of these findings is that, for the period in question, the NHS was a system at the edge of chaos. This hypothesis might explain why waiting times have resisted attempts at shortening.