Lung transplantation in an 18-month-old with donor specific antibodies - The use of intraoperative, targeted plasma exchange

BACKGROUND

Sensitised patients undergoing Human Leukocyte Antigen-incompatible transplantation are at increased risk of hyperacute rejection and may be predisposed to antibody-mediated rejection, chronic lung allograft dysfunction and higher mortality.

CASE

We present a case of primary lung transplantation in the setting of late identification of donor specific antibodies treated with intraoperative target plasma exchange. The patient was treated with fresh human plasma to a final volume of 1.5 times the patient's systemic circulation. From a pre-transplant mean fluorescence intensity of 5002, donor-specific antibodies were undetectable following plasma exchange on single antigen bead assay.

CONCLUSIONS

This method represents a potential desensitisation technique for use in the intraoperative period.

Oxygen delivery in pediatric cardiac surgery and its association with acute kidney injury using machine learning

OBJECTIVE

Acute kidney injury (AKI) after pediatric cardiac surgery with cardiopulmonary bypass (CPB) is a frequently reported complication. In this study we aimed to determine the oxygen delivery indexed to body surface area (Do2i) threshold associated with postoperative AKI in pediatric patients during CPB, and whether it remains clinically important in the context of other known independent risk factors.

METHODS

A single-institution, retrospective study, encompassing 396 pediatric patients, who underwent heart surgery between April 2019 and April 2021 was undertaken. Time spent below Do2i thresholds were compared to determine the critical value for all stages of AKI occurring within 48 hours of surgery. Do2i threshold was then included in a classification analysis with known risk factors including nephrotoxic drug usage, surgical complexity, intraoperative data, comorbidities and ventricular function data, and vasoactive inotrope requirement to determine Do2i predictive importance.

RESULTS

Logistic regression models showed cumulative time spent below a Do2i value of 350 mL/min/m2 was associated with AKI. Random forest models, incorporating established risk factors, showed Do2i threshold still maintained predictive importance. Patients who developed post-CPB AKI were younger, had longer CPB and ischemic times, and required higher inotrope support postsurgery.

CONCLUSIONS

The present data support previous findings that Do2i during CPB is an independent risk factor for AKI development in pediatric patients. Furthermore, the data support previous suggestions of a higher threshold value in children compared with that in adults and indicate that adjustments in Do2i management might reduce incidence of postoperative AKI in the pediatric cardiac surgery population.

A clinical and economic evaluation of Control of Hyperglycaemia in Paediatric intensive care (CHiP): a randomised controlled trial

BACKGROUND

Early research in adults admitted to intensive care suggested that tight control of blood glucose during acute illness can be associated with reductions in mortality, length of hospital stay and complications such as infection and renal failure. Prior to our study, it was unclear whether or not children could also benefit from tight control of blood glucose during critical illness.

OBJECTIVES

This study aimed to determine if controlling blood glucose using insulin in paediatric intensive care units (PICUs) reduces mortality and morbidity and is cost-effective, whether or not admission follows cardiac surgery.

DESIGN

Randomised open two-arm parallel group superiority design with central randomisation with minimisation. Analysis was on an intention-to-treat basis. Following random allocation, care givers and outcome assessors were no longer blind to allocation.

SETTING

The setting was 13 English PICUs.

PARTICIPANTS

Patients who met the following criteria were eligible for inclusion: ≥ 36 weeks corrected gestational age; ≤ 16 years; in the PICU following injury, following major surgery or with critical illness; anticipated treatment > 12 hours; arterial line; mechanical ventilation; and vasoactive drugs. Exclusion criteria were as follows: diabetes mellitus; inborn error of metabolism; treatment withdrawal considered; in the PICU > 5 consecutive days; and already in CHiP (Control of Hyperglycaemia in Paediatric intensive care).

INTERVENTION

The intervention was tight glycaemic control (TGC): insulin by intravenous infusion titrated to maintain blood glucose between 4.0 and 7.0 mmol/l.

CONVENTIONAL MANAGEMENT (CM)

This consisted of insulin by intravenous infusion only if blood glucose exceeded 12.0 mmol/l on two samples at least 30 minutes apart; insulin was stopped when blood glucose fell below 10.0 mmol/l.

MAIN OUTCOME MEASURES

The primary outcome was the number of days alive and free from mechanical ventilation within 30 days of trial entry (VFD-30). The secondary outcomes comprised clinical and economic outcomes at 30 days and 12 months and lifetime cost-effectiveness, which included costs per quality-adjusted life-year.

RESULTS

CHiP recruited from May 2008 to September 2011. In total, 19,924 children were screened and 1369 eligible patients were randomised (TGC, 694; CM, 675), 60% of whom were in the cardiac surgery stratum. The randomised groups were comparable at trial entry. More children in the TGC than in the CM arm received insulin (66% vs. 16%). The mean VFD-30 was 23 [mean difference 0.36; 95% confidence interval (CI) -0.42 to 1.14]. The effect did not differ among prespecified subgroups. Hypoglycaemia occurred significantly more often in the TGC than in the CM arm (moderate, 12.5% vs. 3.1%; severe, 7.3% vs. 1.5%). Mean 30-day costs were similar between arms, but mean 12-month costs were lower in the TGC than in CM arm (incremental costs -£3620, 95% CI -£7743 to £502). For the non-cardiac surgery stratum, mean costs were lower in the TGC than in the CM arm (incremental cost -£9865, 95% CI -£18,558 to -£1172), but, in the cardiac surgery stratum, the costs were similar between the arms (incremental cost £133, 95% CI -£3568 to £3833). Lifetime incremental net benefits were positive overall (£3346, 95% CI -£11,203 to £17,894), but close to zero for the cardiac surgery stratum (-£919, 95% CI -£16,661 to £14,823). For the non-cardiac surgery stratum, the incremental net benefits were high (£11,322, 95% CI -£15,791 to £38,615). The probability that TGC is cost-effective is relatively high for the non-cardiac surgery stratum, but, for the cardiac surgery subgroup, the probability that TGC is cost-effective is around 0.5. Sensitivity analyses showed that the results were robust to a range of alternative assumptions.

CONCLUSIONS

CHiP found no differences in the clinical or cost-effectiveness of TGC compared with CM overall, or for prespecified subgroups. A higher proportion of the TGC arm had hypoglycaemia. This study did not provide any evidence to suggest that PICUs should stop providing CM for children admitted to PICUs following cardiac surgery. For the subgroup not admitted for cardiac surgery, TGC reduced average costs at 12 months and is likely to be cost-effective. Further research is required to refine the TGC protocol to minimise the risk of hypoglycaemic episodes and assess the long-term health benefits of TGC.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN61735247.

FUNDING

This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 18, No. 26. See the NIHR Journals Library website for further project information.

Bronchomegaly as a complication of fetal endoscopic tracheal occlusion. A caution and a possible solution

Fetal medicine is developing rapidly and aims to improve the outcome for fetuses with congenital anomalies. Fetal endoscopic tracheal occlusion (FETO) has been developed for fetuses with congenital diaphragmatic hernia to counterbalance the compression of the lung by the abdominal viscera, preserving the pulmonary maturation. Because the perinatal morbidity and mortality of patients treated with FETO have decreased, new complications are emerging in the older survivors. Tracheomegaly has been reported to be a late complication of FETO, sometimes requiring tracheostomy. We report a case of bronchial dilatation after FETO and suggest an alternative surgical treatment.

Control of hyperglycaemia in paediatric intensive care (CHiP): study protocol

BACKGROUND

There is increasing evidence that tight blood glucose (BG) control improves outcomes in critically ill adults. Children show similar hyperglycaemic responses to surgery or critical illness. However it is not known whether tight control will benefit children given maturational differences and different disease spectrum.

METHODS/DESIGN

The study is an randomised open trial with two parallel groups to assess whether, for children undergoing intensive care in the UK aged <or= 16 years who are ventilated, have an arterial line in-situ and are receiving vasoactive support following injury, major surgery or in association with critical illness in whom it is anticipated such treatment will be required to continue for at least 12 hours, tight control will increase the numbers of days alive and free of mechanical ventilation at 30 days, and lead to improvement in a range of complications associated with intensive care treatment and be cost effective. Children in the tight control group will receive insulin by intravenous infusion titrated to maintain BG between 4 and 7.0 mmol/l. Children in the control group will be treated according to a standard current approach to BG management. Children will be followed up to determine vital status and healthcare resources usage between discharge and 12 months post-randomisation. Information regarding overall health status, global neurological outcome, attention and behavioural status will be sought from a subgroup with traumatic brain injury (TBI). A difference of 2 days in the number of ventilator-free days within the first 30 days post-randomisation is considered clinically important. Conservatively assuming a standard deviation of a week across both trial arms, a type I error of 1% (2-sided test), and allowing for non-compliance, a total sample size of 1000 patients would have 90% power to detect this difference. To detect effect differences between cardiac and non-cardiac patients, a target sample size of 1500 is required. An economic evaluation will assess whether the costs of achieving tight BG control are justified by subsequent reductions in hospitalisation costs.

DISCUSSION

The relevance of tight glycaemic control in this population needs to be assessed formally before being accepted into standard practice.

Cardiac output measurement in pediatric anesthesia

Maintenance of cardiovascular stability is crucial to safe anesthetic practice, but measurement of cardiac output has been technically challenging, particularly in pediatric patients. Cardiovascular monitoring has therefore generally relied upon pressure-based measurements, as opposed to flow-based measurements. The measurement of cardiac output under anesthesia and in critical care has recently become easier as a result of new techniques of measurement. This article reviews the basic concepts of and rationale for cardiac output monitoring, and then describes the techniques available for monitoring in clinical practice.

Asymmetric dimethylarginine causes hypertension and cardiac dysfunction in humans and is actively metabolized by dimethylarginine dimethylaminohydrolase

OBJECTIVE

Plasma levels of an endogenous nitric oxide (NO) synthase inhibitor, asymmetric dimethylarginine (ADMA), are elevated in chronic renal failure, hypertension, and chronic heart failure. In patients with renal failure, plasma ADMA levels are an independent correlate of left ventricular ejection fraction. However, the cardiovascular effects of a systemic increase in ADMA in humans are not known.

METHODS AND RESULTS

In a randomized, double-blind, placebo-controlled study in 12 healthy male volunteers, we compared the effects of intravenous low-dose ADMA and placebo on heart rate, blood pressure, cardiac output, and systemic vascular resistance at rest and during exercise. We also tested the hypothesis that ADMA is metabolized in humans in vivo by dimethylarginine dimethylaminohydrolase (DDAH) enzymes. Low-dose ADMA reduced heart rate by 9.2+/-1.4% from 58.9+/-2.0 bpm (P<0.001) and cardiac output by 14.8+/-1.2% from 4.4+/-0.3 L/min (P<0.001). ADMA also increased mean blood pressure by 6.0+/-1.2% from 88.6+/-3.4 mm Hg (P<0.005) and SVR by 23.7+/-2.1% from 1639.0+/-91.6 dyne. s. cm-5 (P<0.001). Handgrip exercise increased cardiac output in control subjects by 96.8+/-23.3%, but in subjects given ADMA, cardiac output increased by only 35.3+/-10.6% (P<0.05). DDAHs metabolize ADMA to citrulline and dimethylamine. Urinary dimethylamine to creatinine ratios significantly increased from 1.26+/-0.32 to 2.73+/-0.59 after ADMA injection (P<0.01). We estimate that humans generate approximately 300 micromol of ADMA per day, of which approximately 250 micromol is metabolized by DDAHs.

CONCLUSIONS

This study defines the cardiovascular effects of a systemic increase in ADMA in humans. These are similar to changes seen in diseases associated with ADMA accumulation. Finally, our data also indicate that ADMA is metabolized by DDAHs extensively in humans in vivo.

A comparison of cerebral oxygenation as measured by the NIRO 300 and the INVOS 5100 Near-Infrared Spectrophotometers

In this study cerebral oxygenation was measured using the NIRO 300 and the INVOS 5100 spectrophotometers in 10 healthy adult volunteers, exposed to varying degrees of hyperoxia and hypoxia. The results showed similar baseline values for tissue oxygenation index and regional cerebral oxygen saturation with mean (SD) values being 64.9% (5.1) and 62.3% (6.0), respectively. The overall bias was -2.1%, with the INVOS 5100 under-reading cerebral oxygenation compared to the NIRO 300, with limits of agreement of +/-14.7%. Both monitors demonstrated similar changes in response to hyperoxia and hypocapnia (coefficient of variance for FIo2 0.45 = 10.0%, FIo2 1.0 = 10.1%, hypocapnia = 14.5%). The reasons for the bias and variability may relate to differences in the methodological approaches of the two monitors. The correlation between the monitors in response to changes in cerebral oxygenation implies that they may be useful as trend monitors in clinical practice.

Pilot study of sandostatin (octreotide) therapy of refractory HIV-associated diarrhea

Seventeen AIDS patients were enrolled in a prospective open-label dose-finding study of octreotide (Sandostatin) therapy for refractory diarrhea. Five were nonevaluable due to progression of AIDS symptomatology, and one was excluded because of lack of confirmation of HIV infection. Five of 11 evaluable patients responded to therapy (45%); two each at 50 micrograms and 100 micrograms, and one at 250 micrograms thrice daily doses. A sixth patient demonstrated a moderate reduction in stool volume at 250 micrograms thrice daily, which, although deemed clinically relevant, did not meet the criteria for response. On discontinuation of therapy, diarrhea recurred in all patients within 1-12 days, and responded to reinitiation of octreotide in those five patients who resumed treatment. Only one of the three patients with concurrent cryptosporidial infection responded to treatment. The drug was well tolerated, with mild symptomatology in three patients. Long-term treatment at a stable dose was effective in three of five treated patients for periods for seven months in one (moderate responder) and one year in two. One patient required dose increases to control symptoms, but after one year of treatment developed severe nausea following injections, which required dose cessation. One patient had partial control of his diarrhea for only three months despite two dose increases. These data suggest that octreotide may be of useful therapeutic value in HIV-associated diarrhea and that further studies are indicated.

Skin window chambers, a novel method for recovering the cells involved in delayed-type hypersensitivity

A method is described for the recovery of cells involved in the delayed-type hypersensitivity (DTH) reaction in man. A small plastic chamber was placed over DTH sites from which the stratum corneum had been removed by tape stripping. The chambers were then filled with serum. Analysis of cells harvested at 24 and 48 h has shown an antigen-dependent increment in mononuclear and polymorphonuclear cells in donors with a DTH response. T cell clones were established from the recovered cells; these will provide a useful adjunct to a functional analysis of cells participating in the DTH reaction.

The walk-in anergic patient. How best to assess the risk of sepsis following elective surgery

This prospective study evaluated host resistance in a surgical population who walked into the hospital for elective surgery. Patients were stratified into Hospital Reactive (HR, n = 19) if they reacted to two or more of five recall skin test antigens and Walk-in Anergic (WA, n = 26) if they did not react to the antigens. The WA patients were slightly older (74.4 +/- 1.8 years, +/- SEM versus 66.7 +/- 2.7 p less than 0.05). Diagnosis in the HR and WA group were: tumors 13/19 versus 21/26, diverticulitis 3/19 versus 0/19, and miscellaneous 3/19 versus 5/26. Twenty-five laboratory normal controls (LN) were also studied. There were no significant differences in the following parameters between the HR and WA groups: stage of disease; hemoglobin; circulating leukocyte count; polymorphonuclear cell counts; total lymphocyte counts (both groups lower than LN, p less than 0.05), monocyte counts (both higher than LN, p less than 0.05); per cent E-rosettes and lymphocyte blastogenesis to mitogens (phytohemagglutinin, concanavalin-A) and antigens (purified protein derivative and tetanus); phagocytosis of preopsonised Staphylococcus aureus 502A, at 5, 10, and 20 minutes; alpha, beta, and gamma globulins; C3, and total hemolytic complement (CH50) levels; C-reactive protein; and ANA and DNA levels. The HR group demonstrated an increase in the rate of killing of Staphylococcus 502A at 10, 20, 40, and 80 minutes compared to the LN group but the WA group did not show this augmentation (p less than 0.001). The serum albumins were: LN = 4.46, HR = 3.98, WA = 3.43 g/dl (p less than 0.05). Degree and duration of surgery was the same in the HR and WA groups. There were no major sepsis episodes (bacteremia or proven intracavitary abscess) in the HR patients versus 25% in the WA patients (p less than 0.05). There was one death (6%, pulmonary embolus) in the HR group and 8 (40%) in the WA group (p less than 0.05). Antibiotic prophylaxis was equal but the WA patients received therapeutic antibiotics more frequently (65% versus 11% p less than 0.05). Of all the host immunocompetence tests measured in this study, the delayed type hypersensitivity skin test response and the serum albumin were variables abnormal between the survivors and those who died.