Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

Accuracy of AF burden detection with the new Confirm Rx with Sharp-sense technology

Funding Acknowledgements

Type of funding sources: None.

Introduction

Implantable cardiac monitors (ICMs) are increasingly used to monitor atrial fibrillation (AF) burden following catheter ablation. AF burden recorded by the Confirm Rx™ ICM cannot be modified even after adjudication of false-positive (FP) episodes. We sought to investigate accuracy of the AF burden detection in a UK cohort.

Methods

This multicentre retrospective study included patients with Confirm Rx™ and at least one episode >6 minutes across 9 UK hospitals. Each episode had a corresponding 120-second EGM (electrogram) and heart rate scatterplot which was considered representative of the whole episode. One cardiologist adjudicated all EGMs as ‘True AF’ or ‘False positive’ and a random sample of 10% was reviewed to account for intra and interobserver variability. AF burden was computed as the duration of all episodes classified as AF by the Confirm-Rx divided by the total duration of follow-up. ‘True-AF’ burden was calculated by dividing the duration of episodes adjudicated as ‘True-AF’ by the total duration of follow-up. We also investigated the accuracy of AF burden according to implantation indication and episode duration.

Results

A total of 16,230 individual AF episodes were included from 232 consecutive patients. Overall, 26,137 hours of AF were recorded and a total follow-up 315 patient-years which equates to an AF burden of 0.95%. However, only 24,404.7 (93.3%) hours represented time in ‘True-AF’ and a ‘True-AF’ burden for the whole cohort of 0.89% (Table 1). Patients with a Confirm-Rx™ for palpitations and suspected AF had the lowest proportion of ‘True-AF’ burden and had a modest contribution to the overall AF burden (Figure 1). Conversely, patients with known AF had the highest proportion of ‘True-AF’ burden recorded. Most AF (84.5%) episodes lasted less than 1 hour with approximately a quarter adjudicated as false-positive detections, but their contribution towards overall AF burden was very small (Figure 2A-2B). In contrast, AF >3 hours accounted for 76.4% of time in AF and the proportion of ‘True-AF’ burden was 98.5%.

Conclusion

The accuracy of the estimated AF burden for the whole cohort was excellent (93.3%), driven by the high proportion of ‘True-AF’ burden in AF>3 hours.

Diagnostic accuracy of the Confirm-Rx atrial fibrillation detection algorithm in real-world patients

Funding Acknowledgements

Type of funding sources: None.

Introduction

Continuous rhythm monitoring with implantable cardiac monitors (ICMs) is commonly used to detect and characterise atrial fibrillation (AF) episodes. The Confirm Rx™ with SharpSense™ technology offers four new discriminators and second pass analysis aimed at enhancing detection and improving accuracy for cardiac arrhythmias. This study sought to investigate the diagnostic accuracy of the Confirm Rx™ AF detection algorithm in a UK cohort of ‘real-world’ patients.

Methods

This multicentre retrospective study included patients with Confirm Rx™ and at least one episode of AF>6 minutes from August 2018 to August 2021 across 9 UK hospitals. Each episode had a corresponding 120-second electrogram (EGM) and heart rate scatterplot. One cardiologist manually adjudicated all EGMs as ‘True-AF’ or ‘False-positive. To assess for intra and inter-observer variability, 10% of the EGMs were reviewed. Diagnostic accuracy was determined by calculating the raw and patient-averaged positive predictive value (PPV) for AF episode of different durations and implant indications.

Results

During the study 232 patients met inclusion criteria with a total of 315 patient-years of follow-up. 16,320 individual AF episodes were adjudicated; intra- and interobserver variability was excellent (Cohen’s kappa 0.85 and 0.86, respectively). The rate of ‘True-AF’ detection was 3.19 episodes per month corresponding to a raw PPV of 74.5% for the whole cohort. The highest number of episodes per months was observed in patients with a Confirm-Rx for palpitations (5.1) and suspected AF (5.8) but only approximately half of these represented ‘True-AF’ episodes (Figure 1). Patients with known AF had the lowest rate of AF episodes (1.6 episodes per month) but the highest proportion of ‘True-AF’ episodes (PPV of 95.5%). A clear trend of improving diagnostic accuracy was seen with longer AF episodes (Table1). AF>3 hours had a PPV above 94% and all episodes lasting longer than 24 hours were ‘True-AF’. For AF episode of short duration, the PPV varied with the population being monitored; however, for longer AF episodes the PPV increased significantly and irrespective of implant indication (Figure 2).

Conclusion

Overall, the Confirm Rx™ ICM diagnostic accuracy was modest for all AF episodes lasting longer than 6 minutes (74.5%) but improved considerably for longer AF episodes irrespective of implant indication.

Nisin variants from Streptococcus and Staphylococcus successfully express in NZ9800

AIMS

Increases in antimicrobial resistance have meant that the antimicrobial potential of lantibiotics is now being investigated irrespective of the nature of the producing organism. The aim of this study was to investigate whether natural nisin variants produced by non-Generally Recognized as Safe (GRAS) strains, such as nisin H, nisin J and nisin P, could be expressed in a well-characterized GRAS host.

METHODS AND RESULTS

This study involved cloning the nisin A promoter and leader sequence fused to nisin H, nisin J or nisin P structural gene sequences originally produced by Streptococcus hyointestinalis DPC 6484, Staphylococcus capitis APC 2923 and Streptococcus agalactiae DPC 7040, respectively. This resulted in their expression in Lactococcus lactis NZ9800, a genetically modified strain that does not produce nisin A.

CONCLUSIONS

Induction of the nisin controlled gene expression system demonstrates that these three nisin variants could be acted on by nisin A machinery provided by the host strain.

SIGNIFICANCE AND IMPACT OF THE STUDY

Describes the first successful heterologous production of three natural nisin variants by a GRAS strain, and demonstrates how such systems could be harnessed not only for lantibiotic production but also in the expansion of their structural diversity and development for use as future biotherapeutics.

A novel bioengineered derivative of nisin displays enhanced antimicrobial activity against clinical Streptococcus agalactiae isolates

OBJECTIVES

Streptococcus agalactiae is the leading cause of neonatal disease worldwide, and infections caused by this opportunistic pathogen are becoming increasingly more prevalent in adults. With the global incidence of antimicrobial resistance continuing to rise, there is a recognised need for new therapeutic agents. Nisin is a potent antimicrobial peptide with demonstrated broad-spectrum activity against a range of clinically significant pathogens. This study aimed to examine the efficacy of nisin against a clinical population of S. agalactiae isolates and further to investigate the bioactivity of a novel bioengineered derivative of the peptide, designated nisin PV.

METHODS

A deferred antagonism assay was used to assess the bioactivity of wild-type nisin and nisin PV against 122 S. agalactiae isolates. Minimum inhibitory concentrations (MICs) were evaluated to determine the specific activity of both peptides. The genetic basis of nisin resistance among the isolate collection was investigated by PCR detection of the nsr gene.

RESULTS

In total, 91.0% (111/122) of the collection showed some level of susceptibility to nisin, whilst 9.0% (11/122) displayed complete resistance. Interestingly, the nisin derivative exhibited enhanced antimicrobial activity for 64.8% of the isolates. The frequency of the nsr gene conferring nisin resistance was 98.4% (120/122), suggesting that resistance may be linked to levels of expression of the protein or other regulatory elements.

CONCLUSION

This study indicates that there is potential for the use of nisin and its derivatives as therapeutic agents against S. agalactiae infections.

Librating dipoles as a probe of spontaneously electrical films and as a source of THz radiation

Pulsing a spontaneously electrical solid causes the molecular dipoles to oscillate and emit THz radiation.

Assigning a structural motif using spontaneous molecular dipole orientation in thin films

Guided by the spontelectric behaviour of thin films of cis-methyl formate, infrared observations and computational investigations reveal the dimer structural motif of the crystalline solid.

Non-linear and non-local behaviour in spontaneously electrical solids

We show that solids displaying spontaneous dipole orientation possess quite general non-local and non-linear characteristics expressed through their internal electric fields.

Effects of the community-based Wellspring Cancer Exercise Program on functional and psychosocial outcomes in cancer survivors

PURPOSE

In this study, we examined the effects of a 30-week community-based exercise program on cancer-related fatigue, quality of life, and other health-related outcomes in a sample of adults with mixed cancer diagnoses.

METHODS

This prospective cohort study looked at outcomes for participants involved in the Wellspring Cancer Exercise Program in southern Ontario. The program consisted of an initial phase of two supervised sessions weekly for 10 weeks and a transition phase of one supervised session weekly for the subsequent 20 weeks. Outcomes were measured at baseline and every 10 weeks throughout the intervention, as well as at 16 weeks after program completion.

RESULTS

During a period of 13 months, 229 of the 355 cancer survivors who enrolled in the exercise program consented to participate in the study. Participants attended 71% of the supervised exercise sessions in the initial phase and 49% in the transition phase. From baseline to the end of the initial phase, significant improvements in cancer-related fatigue, 6-minute walk test, social well-being, systolic blood pressure, balance, and physical activity volume were observed. During the transition phase, health-related quality of life and emotional well-being improved significantly.

CONCLUSIONS

The Wellspring Cancer Exercise Program is associated with clinically meaningful improvements in cancer-related fatigue and functional aerobic capacity. Several other aspects of well-being in cancer survivors also improved for participants in the program. Community-based cancer exercise programs such as the Wellspring Cancer Exercise Program can improve well-being for cancer survivors and can provide an effective option that enhances sustainability and accessibility to exercise services for this population.

Effects of the community-based Wellspring Cancer Exercise Program on functional and psychosocial outcomes in cancer survivors

PURPOSE

In this study, we examined the effects of a 30-week community-based exercise program on cancer-related fatigue, quality of life, and other health-related outcomes in a sample of adults with mixed cancer diagnoses.

METHODS

This prospective cohort study looked at outcomes for participants involved in the Wellspring Cancer Exercise Program in southern Ontario. The program consisted of an initial phase of two supervised sessions weekly for 10 weeks and a transition phase of one supervised session weekly for the subsequent 20 weeks. Outcomes were measured at baseline and every 10 weeks throughout the intervention, as well as at 16 weeks after program completion.

RESULTS

During a period of 13 months, 229 of the 355 cancer survivors who enrolled in the exercise program consented to participate in the study. Participants attended 71% of the supervised exercise sessions in the initial phase and 49% in the transition phase. From baseline to the end of the initial phase, significant improvements in cancer-related fatigue, 6-minute walk test, social well-being, systolic blood pressure, balance, and physical activity volume were observed. During the transition phase, health-related quality of life and emotional well-being improved significantly.

CONCLUSIONS

The Wellspring Cancer Exercise Program is associated with clinically meaningful improvements in cancer-related fatigue and functional aerobic capacity. Several other aspects of well-being in cancer survivors also improved for participants in the program. Community-based cancer exercise programs such as the Wellspring Cancer Exercise Program can improve well-being for cancer survivors and can provide an effective option that enhances sustainability and accessibility to exercise services for this population.

Wannier-Mott Excitons in Nanoscale Molecular Ices

The absorption of light to create Wannier-Mott excitons is a fundamental feature dictating the optical and photovoltaic properties of low band gap, high permittivity semiconductors. Such excitons, with an electron-hole separation an order of magnitude greater than lattice dimensions, are largely limited to these semiconductors but here we find evidence of Wannier-Mott exciton formation in solid carbon monoxide (CO) with a band gap of >8  eV and a low electrical permittivity. This is established through the observation that a change of a few degrees K in deposition temperature can shift the electronic absorption spectra of solid CO by several hundred wave numbers, coupled with the recent discovery that deposition of CO leads to the spontaneous formation of electric fields within the film. These so-called spontelectric fields, here approaching 4×10^{7}  V m^{-1}, are strongly temperature dependent. We find that a simple electrostatic model reproduces the observed temperature dependent spectral shifts based on the Stark effect on a hole and electron residing several nm apart, identifying the presence of Wannier-Mott excitons. The spontelectric effect in CO simultaneously explains the long-standing enigma of the sensitivity of vacuum ultraviolet spectra to the deposition temperature.

Estimates of length of neonatal stay for very premature babies in the UK

OBJECTIVE

To describe simple estimates of likely duration of stay for very premature babies born in the UK and discharged home.

DESIGN

Statistical modelling of data from thirty neonatal units in a geographically defined region of the UK.

PARTICIPANTS

All babies born at 23 to 32 completed weeks of gestation in 2005, 2006 and 2007 who were discharged home with the expectation that they would survive.

MAIN OUTCOME MEASURE

Total duration of stay in the neonatal service.

RESULTS

5528 babies were initially identified. 558 (10.1%) who died or who did not follow a normal care pathway were excluded. In a further 27, data were either missing or inadequate, leaving a study population of 4702 babies. As expected, gestation and birthweight exhibited strong influence on length of stay. Of the other variables tested, initial reason for admission (need for early respiratory support) showed the most consistent association. These factors were combined to produce predictive tables. The predictive performance of the tables was found to fit the data well for various groups, with the exception of multiple births who tended to have longer stays. However, when tested against individual units, much greater variation was seen independent of unit size and case mix.

CONCLUSION

The prediction tables should permit parents to make sensible estimates about the duration of their baby's stay in the neonatal service; however, there appear to be important differences between units. The variation noted in length of stay between otherwise similar units merits further investigation.

Prioritising neonatal medicines research: UK Medicines for Children Research Network scoping survey

Background

The dosing regimen and indications for many medicines in current use in neonatology are not well defined. There is a need to prioritise research in this area, but currently there is little information about which drugs are used in UK neonatal units and the research needs in this area as perceived by UK neonatologists.

Methods

The Neonatal Clinical Studies Group (CSG) of the Medicines for Children Research Network (MCRN) undertook a 2 week prospective scoping survey study to establish which medicines are used in UK neonatal units; how many babies are receiving them; and what clinicians (and other health professionals) believe are important issues for future research.

Results

49 out of 116 units responded to at least one element of the survey (42%). 37 units reported the number of neonates who received medicines over a 2 week period. A total of 3924 medicine-patient pairs were reported with 119 different medicines. 70% of medicine-patient pairs involved medicines that were missing either a license or dose for either term or preterm neonates. 4.3% of medicine-patient pairs involved medicines that were missing both license and dose for any neonate. The most common therapeutic gap in need of additional research identified by UK neonatologists was chronic lung disease (21 responding units), followed by patent ductus arteriosus and vitamin supplements (11 responding units for both)

Conclusion

The research agenda for neonatal medicines can be informed by knowledge of current medicine use and the collective views of the neonatal community.

Rates of very preterm birth in Europe and neonatal mortality rates

OBJECTIVE

To estimate the influence of variation in the rate of very preterm delivery on the reported rate of neonatal death in 10 European regions.

DESIGN

Comparison of 10 separate geographically defined European populations, from nine European countries, over a 1-year period (7 months in one region).

PARTICIPANTS

All births that occurred between 22(+0) and 31(+6) weeks of gestation in 2003.

MAIN OUTCOME MEASURE

Neonatal death rate adjusted for rate of delivery at this gestation.

RESULTS

Rate of delivery of all births at 22(+0)-31(+6) weeks of gestation and live births only were calculated for each region. Two regions had significantly higher rates of very preterm delivery per 1000 births: Trent UK (16.8, 95% CI 15.7 to 17.9) and Northern UK (17.1, 95% CI 15.6 to 18.6); group mean 13.2 (95% CI 12.9 to 13.5). Four regions had rates significantly below the group average: Portugal North (10.7, 95% CI 9.6 to 11.8), Eastern and Central Netherlands (10.6, 95% CI 9.7 to 11.6), Eastern Denmark (11.2, 95% CI 10.1 to 12.4) and Lazio in Italy (11.0, 95% CI 10.1 to 11.9). Similar trends were seen in live birth data. Published rates of neonatal death for each region were then adjusted by applying (a) a standardised rate of very preterm delivery and (b) the existing death rate for babies born at this gestation in the individual region. This produced much greater homogeneity in terms of neonatal mortality.

CONCLUSIONS

Variation in the rate of very preterm delivery has a major influence on reported neonatal death rates.

Spontaneous dipole alignment in films of N2O

Experimental data obtained using low energy electron beams are presented which show that films of N2O, of several hundred monolayers (ML), spontaneously acquire a positive potential of as high as 5 V. Films do not possess a dipole double layer but for >40 ML display a constant electric field within the material. This new phenomenon is attributed to dipole alignment. The phenomenon also shows a strong temperature dependence. This is revealed by the differing dependence of the surface potential on the film thickness at different temperatures and by electron transmission spectra which display marked structure at 62 K which is absent at 40 K.

The INNOVO multicentre randomised controlled trial: neonatal ventilation with inhaled nitric oxide versus ventilatory support without nitric oxide for severe respiratory failure in preterm infants: follow up at 4-5 years

BACKGROUND

Trials of inhaled nitric oxide (iNO) used short term in preterm infants with severe respiratory failure have to date shown no evidence of benefit, and there have been no trials reporting follow-up to 4 years of age. The INNOVO trial recruited 108 infants (55 iNO arm and 53 controls) from 15 neonatal units. By 1 year of age 59% had died, and 84% of the survivors had signs of impairment or disability.

OBJECTIVE

This paper reports the long-term clinical effectiveness and costs of adding NO to the ventilator gases of preterm infants with severe respiratory failure.

PATIENTS AND METHODS

Children were assessed at age 4-5 years by interview, examination, cognitive and behavioural assessments. The outcome data were divided into seven domains and were described as normal, impaired or disabled (mild, moderate or severe) by the degree of functional loss.

RESULTS

38 of the 43 survivors had follow-up assessments. In the iNO group 62% (34/55) had died or were severely disabled, compared to 70% (37/53) in the no iNO group (RR 0.89, 95% CI 0.67 to 1.16). There was no evidence of difference in the levels of impairment or disability between the two groups in any of the domains studied, or of cost differences, amongst the survivors.

CONCLUSION

For this group of babies with severe respiratory failure there was no evidence of difference in the longer-term outcome between those babies allocated to iNO and those who were allocated to no iNO. The challenge is to identify those premature babies who are able to respond to NO with clinically important health improvements.

TRIAL REGISTRATION NUMBER

17821339.

Geographically based investigation of the influence of very-preterm births on routine mortality statistics from the UK and Australia

BACKGROUND

Comparisons of national perinatal and neonatal mortality often neglect the underlying causes.

OBJECTIVE

To assess effects of very-preterm births in the UK and Australia.

SETTING

Two geographically defined populations: the former Trent Health Region of the UK and New South Wales (NSW)/the Australian Capital Territory (ACT), Australia.

METHOD

All births 22(+0) to 31(+6) weeks in 2000, 2001 and 2002 were identified by established surveys of perinatal care. Rates of birth and death were compared.

RESULTS

The population of NSW/ACT was 35% higher and there were 66% more births than in Trent (273 495 vs 164 824). The proportion of liveborn infants between 22 and 31 weeks gestation was about 25% higher in Trent (NSW/ACT 2945, rate per 1000 live births 10.82 (95% CI 10.43 to 11.22); Trent 2208, rate per 1000 live births 13.47 (95% CI 12.92 to 14.05)). The proportion of these infants admitted to a neonatal unit was also higher in Trent (91.2% vs 94.4%; OR 1.63 (95% CI 1.30 to 2.05)). Unadjusted mortality in infants admitted to a neonatal unit was similar: NSW/ACT 332/2686 (12.4%); Trent 284/2085 (13.6%); unadjusted OR 1.12 (95% CI 0.94 to 1.33; p = 0.21).

CONCLUSIONS

The higher rates of very premature birth and more ready admission to neonatal intensive care for infants in the UK may help to explain why perinatal and neonatal mortality are higher there than in Australia. Efforts to understand why the rate of premature birth in the UK is so high should be a national priority.

Referral pattern of neonates with severe respiratory failure for extracorporeal membrane oxygenation

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) remains the mainstay of management in neonates with severe but potentially reversible respiratory failure. In the UK, ECMO is available only as a supraregional service at four centres.

OBJECTIVE

To explore regional variations in ECMO referrals and neonatal deaths due to severe respiratory failure in England, Wales and Northern Ireland.

METHODS

In this retrospective study, data regarding ECMO referrals due to neonatal respiratory failure from January to December 2002 were obtained from the four UK ECMO centres and then subdivided according to the Government Office Regions. Anonymised data regarding neonatal deaths was obtained from Confidential Enquiry into Maternal and Child Health. Neonatal deaths were classified into four groups (group 1: deaths potentially avoidable by ECMO; group 2: deaths where it was unclear whether ECMO would have been of benefit; group 3: neonates not eligible for ECMO; and group 4: data inadequate to classify deaths).

RESULTS

There was significant regional variation in the rates of both ECMO referral (0.10 to 0.46 per 1000 live births; (p<0.001)) and neonatal deaths (groups 1 and 2) (0.09 to 0.32 per 1000 live births; (p<0.001)). Regions with high referral rates for ECMO tended towards having higher group 1 plus group 2 neonatal death rates (correlation coefficient = 0.75).

CONCLUSION

It is possible that there are significant regional variations in the uptake of ECMO and in neonatal mortality due to severe respiratory failure. A confidential prospective study may further clarify these observations and identify the factors that might lead to these variations.

Ethnic variations in the incidence and outcome of severe retinopathy of prematurity

BACKGROUND

The aim of this study was to assess the incidence and outcome of severe retinopathy of prematurity (ROP) among different ethnic groups in a geographically defined population in the U.K. Severe ROP was defined as any stage 3 or worse disease.

METHODS

This was a retrospective study of children born over a 6-year period with a birth weight of 1250 g or less. Threshold ROP was treated with diode laser.

RESULTS

Severe disease developed in 37 out of 355 neonates (10.4%) who underwent ROP screening. The difference in the incidence of severe ROP between infants of Caucasian and South Asian ethnic origin was not statistically significant: 10.2% vs. 10.8% (odds ratio = 1.06; 95% confidence interval: 0.44 to 2.57). This conclusion held after single-variable adjustment for birth weight, gestational age, and score on the Clinical Risk Index for Babies. The incidence of threshold ROP was 3% among infants of both Caucasian and South Asian ethnic origin. There was no significant difference in terms of visual outcome between the Caucasian and South Asian infants.

INTERPRETATION

This study showed no statistical evidence for a difference in the incidence or outcome of severe ROP among infants of South Asian ethnic origin compared with those of Caucasian origin. Although the small numbers in our study mean that a clinically important difference cannot be excluded, it is very unlikely that the 5-fold higher incidence in Asian babies described in the literature is correct for the population from which our subjects were drawn.

Neonatal ventilation with inhaled nitric oxide vs. ventilatory support without inhaled nitric oxide for infants with severe respiratory failure born at or near term: the INNOVO multicentre randomised controlled trial

BACKGROUND

Evidence from European centres to support the use of nitric oxide (NO) in mature newborns with evidence of severe respiratory failure is sparse.

METHODS

Infants of >33 weeks' gestation, <28 days old, and with severe respiratory failure requiring ventilatory support were randomised to receive or not to receive inhaled NO (iNO). The study was not blinded.

RESULTS

Sixty infants were recruited (29 allocated iNO, 31 no iNO) from 15 neonatal units in the UK, Finland, Belgium and the Republic of Ireland. 15/60 recruited babies died, and 8.1% of the survivors (4/45) were classified as severely disabled at 1 year. There was no statistically significant difference between the randomised groups in terms of the primary outcome of death or severe disability by the corrected age of 1 year (relative risk = 0.96 (95% confidence interval = 0.46-2.03); p = 0.86) (Fisher's exact p = 1.00). The costs of NO were outweighed by reduced extra corporeal membrane oxygenation costs in the iNO group. The mean total hospitalisation costs were lower in the iNO group, although the mean difference (1,697 pounds) was not statistically significant (95% confidence interval = -14,472 to 11,478).

CONCLUSIONS

The results complement those of previous studies that suggest NO is cost-effective and reduces the need for extra corporeal membrane oxygenation in this group of babies. Overall survival rates compare unfavourably with results of US trials.

Rotational excitation of H2O by cold electrons

Experimental data are presented for the scattering of electrons by H2O between 17 and 250 meV impact energy. These results are used in conjunction with a generally applicable method, based on a quantum defect theory approach to electron-polar molecule collisions, to derive the first set of data for state-to-state rotationally inelastic scattering cross sections based on experimental values.

A dose response study of inhaled nitric oxide in hypoxic respiratory failure in preterm infants

BACKGROUND

Inhaled nitric oxide (iNO) is used widely in newborn infants with hypoxic respiratory failure, despite the known and theoretical toxicity of iNO, and a relative lack of information about appropriate doses.

AIM

To determine whether a dose-response relationship existed for iNO in preterm infants.

DESIGN

A four-period, four-dose, cross-over design was used with iNO given for 15 min in a randomised sequence in concentrations of 5, 10, 20 and 40 parts per million (ppm), with a minimum 5 min wash-out period. Data on ventilatory, blood gas and other physiological measurements were recorded before and at the end of each period. The relationship of clinical response with iNO dose and period was analysed using multivariate regression.

SUBJECTS

Infants with gestational age < 34 weeks and < 28 days postnatal age with hypoxic respiratory failure were recruited.

OUTCOME MEASURE

A clinically significant dose-response was defined as a rise in the post-ductal arterial oxygen tension (PaO(2)) of at least 3 kPa.

RESULTS

Thirteen infants were recruited. At trial entry, ten were < 3 days of age; 11 were being treated with high frequency oscillatory ventilation; median (inter-quartile range) gestational age 27 (25-29) weeks; birthweight 983 (765-1120) g; oxygenation index 27.1 (21.8-28.8). Six infants (46%) showed a clinically significant response. After adjusting for period and patient effect, no evidence for an overall dose effect was identified (likelihood ratio test, p=0.34).

CONCLUSION

No evidence of a dose-response relationship with iNO was found in this study of very preterm infants with respiratory failure.