Opioids for newborn infants receiving mechanical ventilation

Fentanyl dosage for preterm infants suggested by a pharmacokinetic, -dynamic, and -genetic model

BACKGROUND

Fentanyl is commonly administered for procedural pain management in preterm infants, but target concentrations have not yet been defined.

METHODS

To investigate pharmacokinetics (PK), -dynamics (PD), and -genetics (PG), 25 infants (gestational age 23.3-34.1 weeks) received a fentanyl dose before a skin-breaking procedure (0.5 µg/kg) or tracheal intubation (2 µg/kg). Four pain scales were used as a PD endpoint to evaluate efficacy. The impact of polymorphism in genes encoding enzymes (UGT2B7, CYP3A7, CYP3A4, COMT, CYP2D6, KCNJ6), transporters (SLC22A1, ABCC1, ABCC3) and receptor (OPRM1) on PK parameters was explored.

RESULTS

A two-compartment PK model adequately described the fentanyl concentration. The effects of weight and maturity on the clearance were included as covariates in the model. One genetic variant encoding the ABCC1 transporter (rs111517339 T/TA) and two encoding the ABCC3 transporter (rs11079921 T/C and rs8077268 C/T) had a significant effect on fentanyl elimination that explained 15% of the interindividual variability on the clearance. A proportional odds PK/PD model was used to describe the concentration-effect relationship of fentanyl using the Échelle de douleur et d'inconfort du nouveau-né (EDIN) pain score.

CONCLUSION

The simulations suggest that an intravenous dose of 2 µg/kg would be appropriate in preterm infants for a clearly painful procedure, such as an intubation.

IMPACT

Design of personalized analgesia with fentanyl for newborn infants should consider maturation and genetic variants of opioid transporters affecting drug elimination. The results indicate that an intravenous dose of 2 μg/kg fentanyl would be suitable before a clearly painful procedure in preterm infants. Genetic variants encoding ABCC1 and ABCC3 transporters increase the clearance of fentanyl, which is a novel finding.

The relationship between neonatal stress in preterm infants and developmental outcomes at the corrected age of 24-30 months

Aim

The aim of research was to study the relationship between the stress experienced by preterm infants in the neonatal intensive care unit (NICU) and developmental status in the follow up, and to establish factors, associated with their neurodevelopment.

Methods

The first stage of research involved measuring stress markers (cortisol, melatonin) in infants (n = 56) during their NICU stay; the second phase assessed the developmental status at the corrected age of 24-30 months.

Results

The total ASQ-3 score, communication, problem solving, and personal-social skills scores at the corrected age of 24-30 months were positively correlated with melatonin level determined in the neonatal period (r = 0.31, p = 0.026; r = 0.36, p = 0.009; r = 0.30, p = 0.033, and r = 0.32; p = 0.022 respectively). In the same time, ASQ-3 communication and personal-social scores were negatively correlated with cortisol level (r = -0.31, p = 0.043; r = -0.35, p = 0.022). The ROC-curve analysis revealed that a decrease of melatonin below 3.44 ng/mL and 3.71 ng/mL during the neonatal period could predict communication and problem-solving delay, respectively. An increase in cortisol above 0.64 mcg/dl is predictive in personal-social delay. Negative correlation was identified between the NICU and total hospital stay duration and ASQ-3 communication scores in the follow-up (r = -0.27; p = 0.049 and r = -0.41; p = 0.002, respectively). The duration of mechanical ventilation was negatively correlated with gross motor scores (r = -0.46; p = 0.043). Apgar score was positively correlated with ASQ-3 communication (r = 0.29; p = 0.032) and personal-social scores (r = 0.28; p = 0.034); maternal age-with ASQ-3 total (r = 0.29; p = 0.034), communication (r = 0.37; p = 0.006), and personal-social scores (r = 0.29; p = 0.041). Positive correlations were observed between gestational age and communication scores (r = 0.28; p = 0.033). Infants who suffered neonatal sepsis had significantly often delay of communication (p = 0.014) and gross motor skills (p = 0.016). Children who required mechanical ventilation were more likely to have communication delay (p = 0.034).

Conclusion

Developmental outcomes in preterm infants at the corrected age of 24-30 months were associated with neonatal stress. Correlations between the communication, problem-solving and personal-social development in the follow up and cortisol and melatonin levels determined in the neonatal period supported this evidence. Factors as low gestational age, duration of hospital and NICU stay, mechanical ventilation, and sepsis were associated with more frequent delays in communication, gross motor and problems-solving skills.

Global cross-sectional survey on neonatal pharmacologic sedation and analgesia practices and pain assessment tools: impact of the sociodemographic index (SDI)

BACKGROUND

There is variability in the use of sedatives and analgesics in neonatal intensive care units (NICUs). We aimed to investigate the use of analgesics and sedatives and the management of neonatal pain and distress.

METHODS

This was a global, prospective, cross-sectional study. A survey was distributed May-November 2022. The primary outcome of this research was to compare results between countries depending on their socio-sanitary level using the sociodemographic index (SDI). We organized results based on geographical location.

RESULTS

The survey collected 1304 responses, but we analyzed 924 responses after database cleaning. Responses from 98 different countries were analyzed. More than 60% of NICUs reported having an analgosedation guideline, and one-third of respondents used neonatal pain scales in more than 80% of neonates. We found differences in the management of sedation and analgesia between NICUs on different continents, but especially between countries with different SDIs. Countries with a higher SDI had greater availability of and adherence to analgosedation guidelines, as well as higher rates of analgosedation for painful or distressing procedures. Countries with different SDIs reported differences in analgosedation for neonatal intubation, invasive ventilation, and therapeutic hypothermia, among others.

CONCLUSIONS

Socio-economic status of countries impacts on neonatal analgosedation management.

IMPACT

There is significant variability in the pain management practices in neonates. There is a lack of knowledge related to how neonatal pain management practices differ between regions. Sociodemographic index is a key factor associated with differences in neonatal pain management practices across global regions.

Association between opioid use during mechanical ventilation in preterm infants and evidence of brain injury: a propensity score-matched cohort study

Background

Preterm infants often require mechanical ventilation (MV), which can be a painful experience. Opioids (such as morphine) are used to provide analgesia, despite conflicting evidence about their impact on the developing brain. We aimed to quantify the use of opioids during MV in infants born at <32 weeks' gestational age and to investigate the association between opioid use and evidence of brain injury.

Methods

In this retrospective propensity score-matched cohort study, we used routinely recorded data from the National Neonatal Research Database to study infants born at 22-31 weeks gestational age who were admitted to neonatal units in England and Wales (between Jan 1, 2012, and Dec 31, 2020) and who were mechanically ventilated on one or more days during their hospital stay. We used propensity score matching to identify pairs of infants (one who received opioids during MV and one who did not) with similar demographic and clinical characteristics. The pre-specified primary outcome was preterm brain injury assessed in all infants who received MV for more than two days and had evidence of preterm brain injury at or before discharge from neonatal care. Adjusted analyses accounted for differences in infants' characteristics, including illness severity and painful/surgical conditions.

Findings

Of 67,206 infants included, 45,193 (67%) were mechanically ventilated for one or more days and 26,201 (58% of 45,193) received an opioid whilst ventilated. Opioids were given for a median of 67% of ventilated days (IQR 43-92%) and the median exposure was 4 days (2-11). The percentage of mechanically ventilated infants who received opioids while ventilated increased from 52% in 2012 to 60% in 2020 (morphine, 51%-56%; fentanyl, 6%-18%). In the propensity score-matched cohort of 3608 pairs who were ventilated for >2 consecutive days, the odds of any preterm brain injury (adjusted odds ratio 1.22, 95% CI 1.10-1.35) were higher in those who received opioids compared with those who did not (received opioids, 990/3608 (27.4%) vs. did not receive opioids, 855/3608 (23.7%). The adjusted odds of these adverse outcomes increased with increasing number of days of opioid exposure.

Interpretation

Use of opioids during mechanical ventilation of preterm infants increased during the study period (2012-2020). Although causation cannot be determined, among those ventilated for >2 consecutive days, these data suggest that opioid use is associated with an increased risk of preterm brain injury and the risk increases with longer durations of exposure.

Funding

University of Nottingham Impact Fund.

Pharmacological pain and sedation interventions for the prevention of intraventricular hemorrhage in preterm infants on assisted ventilation - an overview of systematic reviews

BACKGROUND

Germinal matrix hemorrhage and intraventricular hemorrhage (GMH-IVH) may contribute to neonatal morbidity and mortality and result in long-term neurodevelopmental sequelae. Appropriate pain and sedation management in ventilated preterm infants may decrease the risk of GMH-IVH; however, it might be associated with harms.

OBJECTIVES

To summarize the evidence from systematic reviews regarding the effects and safety of pharmacological interventions related to pain and sedation management in order to prevent GMH-IVH in ventilated preterm infants.

METHODS

We searched the Cochrane Library August 2022 for reviews on pharmacological interventions for pain and sedation management to prevent GMH-IVH in ventilated preterm infants (< 37 weeks' gestation). We included Cochrane Reviews assessing the following interventions administered within the first week of life: benzodiazepines, paracetamol, opioids, ibuprofen, anesthetics, barbiturates, and antiadrenergics. Primary outcomes were any GMH-IVH (aGMH-IVH), severe IVH (sIVH), all-cause neonatal death (ACND), and major neurodevelopmental disability (MND). We assessed the methodological quality of included reviews using the AMSTAR-2 tool. We used GRADE to assess the certainty of evidence.

MAIN RESULTS

We included seven Cochrane Reviews and one Cochrane Review protocol. The reviews on clonidine and paracetamol did not include randomized controlled trials (RCTs) matching our inclusion criteria. We included 40 RCTs (3791 infants) from reviews on paracetamol for patent ductus arteriosus (3), midazolam (3), phenobarbital (9), opioids (20), and ibuprofen (5). The quality of the included reviews was high. The certainty of the evidence was moderate to very low, because of serious imprecision and study limitations. Germinal matrix hemorrhage-intraventricular hemorrhage (any grade) Compared to placebo or no intervention, the evidence is very uncertain about the effects of paracetamol on aGMH-IVH (risk ratio (RR) 0.89, 95% confidence interval (CI) 0.38 to 2.07; 2 RCTs, 82 infants; very low-certainty evidence); midazolam may result in little to no difference in the incidence of aGMH-IVH (RR 1.68, 95% CI 0.87 to 3.24; 3 RCTs, 122 infants; low-certainty evidence); the evidence is very uncertain about the effect of phenobarbital on aGMH-IVH (RR 0.99, 95% CI 0.83 to 1.19; 9 RCTs, 732 infants; very low-certainty evidence); opioids may result in little to no difference in aGMH-IVH (RR 0.85, 95% CI 0.65 to 1.12; 7 RCTs, 469 infants; low-certainty evidence); ibuprofen likely results in little to no difference in aGMH-IVH (RR 0.99, 95% CI 0.81 to 1.21; 4 RCTs, 759 infants; moderate-certainty evidence). Compared to ibuprofen, the evidence is very uncertain about the effects of paracetamol on aGMH-IVH (RR 1.17, 95% CI 0.31 to 4.34; 1 RCT, 30 infants; very low-certainty evidence). Compared to midazolam, morphine may result in a reduction in aGMH-IVH (RR 0.28, 95% CI 0.09 to 0.87; 1 RCT, 46 infants; low-certainty evidence). Compared to diamorphine, the evidence is very uncertain about the effect of morphine on aGMH-IVH (RR 0.65, 95% CI 0.40 to 1.07; 1 RCT, 88 infants; very low-certainty evidence). Severe intraventricular hemorrhage (grade 3 to 4) Compared to placebo or no intervention, the evidence is very uncertain about the effect of paracetamol on sIVH (RR 1.80, 95% CI 0.43 to 7.49; 2 RCTs, 82 infants; very low-certainty evidence) and of phenobarbital (grade 3 to 4) (RR 0.91, 95% CI 0.66 to 1.25; 9 RCTs, 732 infants; very low-certainty evidence); opioids may result in little to no difference in sIVH (grade 3 to 4) (RR 0.98, 95% CI 0.71 to 1.34; 6 RCTs, 1299 infants; low-certainty evidence); ibuprofen may result in little to no difference in sIVH (grade 3 to 4) (RR 0.82, 95% CI 0.54 to 1.26; 4 RCTs, 747 infants; low-certainty evidence). No studies on midazolam reported this outcome. Compared to ibuprofen, the evidence is very uncertain about the effects of paracetamol on sIVH (RR 2.65, 95% CI 0.12 to 60.21; 1 RCT, 30 infants; very low-certainty evidence). Compared to midazolam, the evidence is very uncertain about the effect of morphine on sIVH (grade 3 to 4) (RR 0.08, 95% CI 0.00 to 1.43; 1 RCT, 46 infants; very low-certainty evidence). Compared to fentanyl, the evidence is very uncertain about the effect of morphine on sIVH (grade 3 to 4) (RR 0.59, 95% CI 0.18 to 1.95; 1 RCT, 163 infants; very low-certainty evidence). All-cause neonatal death Compared to placebo or no intervention, the evidence is very uncertain about the effect of phenobarbital on ACND (RR 0.94, 95% CI 0.51 to 1.72; 3 RCTs, 203 infants; very low-certainty evidence); opioids likely result in little to no difference in ACND (RR 1.12, 95% CI 0.80 to 1.55; 5 RCTs, 1189 infants; moderate-certainty evidence); the evidence is very uncertain about the effect of ibuprofen on ACND (RR 1.00, 95% CI 0.38 to 2.64; 2 RCTs, 112 infants; very low-certainty evidence). Compared to midazolam, the evidence is very uncertain about the effect of morphine on ACND (RR 0.31, 95% CI 0.01 to 7.16; 1 RCT, 46 infants; very low-certainty evidence). Compared to diamorphine, the evidence is very uncertain about the effect of morphine on ACND (RR 1.17, 95% CI 0.43 to 3.19; 1 RCT, 88 infants; very low-certainty evidence). Major neurodevelopmental disability Compared to placebo, the evidence is very uncertain about the effect of opioids on MND at 18 to 24 months (RR 2.00, 95% CI 0.39 to 10.29; 1 RCT, 78 infants; very low-certainty evidence) and at five to six years (RR 1.6, 95% CI 0.56 to 4.56; 1 RCT, 95 infants; very low-certainty evidence). No studies on other drugs reported this outcome.

AUTHORS' CONCLUSIONS

None of the reported studies had an impact on aGMH-IVH, sIVH, ACND, or MND. The certainty of the evidence ranged from moderate to very low. Large RCTs of rigorous methodology are needed to achieve an optimal information size to assess the effects of pharmacological interventions for pain and sedation management for the prevention of GMH-IVH and mortality in preterm infants. Studies might compare interventions against either placebo or other drugs. Reporting of the outcome data should include the assessment of GMH-IVH and long-term neurodevelopment.

Opioids for procedural pain in neonates

BACKGROUND

Neonates might be exposed to numerous painful procedures due to diagnostic reasons, therapeutic interventions, or surgical procedures. Options for pain management include opioids, non-pharmacological interventions, and other drugs. Morphine, fentanyl, and remifentanil are the opioids most often used in neonates. However, negative impact of opioids on the structure and function of the developing brain has been reported.

OBJECTIVES

To evaluate the benefits and harms of opioids in term or preterm neonates exposed to procedural pain, compared to placebo or no drug, non-pharmacological intervention, other analgesics or sedatives, other opioids, or the same opioid administered by a different route.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search date was December 2021.

SELECTION CRITERIA

We included randomized controlled trials conducted in preterm and term infants of a postmenstrual age (PMA) up to 46 weeks and 0 days exposed to procedural pain where opioids were compared to 1) placebo or no drug; 2) non-pharmacological intervention; 3) other analgesics or sedatives; 4) other opioids; or 5) the same opioid administered by a different route.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were pain assessed with validated methods and any harms. We used a fixed-effect model with risk ratio (RR) for dichotomous data and mean difference (MD) for continuous data, and their confidence intervals (CI). We used GRADE to assess the certainty of the evidence for each outcome.

MAIN RESULTS

We included 13 independent studies (enrolling 823 newborn infants): seven studies compared opioids to no treatment or placebo (the main comparison in this review), two studies to oral sweet solution or non-pharmacological intervention, and five studies (of which two were part of the same study) to other analgesics and sedatives. All studies were performed in a hospital setting. Opioids compared to placebo or no drug Compared to placebo, opioids probably reduce pain score assessed with the Premature Infant Pain Profile (PIPP)/PIPP-Revised (PIPP-R) scale during the procedure (MD -2.58, 95% CI -3.12 to -2.03; 199 participants, 3 studies; moderate-certainty evidence); may reduce Neonatal Infant Pain Scale (NIPS) during the procedure (MD -1.97, 95% CI -2.46 to -1.48; 102 participants, 2 studies; low-certainty evidence); and may result in little to no difference in pain score assessed with the Douleur Aiguë du Nouveau-né (DAN) scale one to two hours after the procedure (MD -0.20, 95% CI -2.21 to 1.81; 42 participants, 1 study; low-certainty evidence). The evidence is very uncertain about the effect of opioids on pain score assessed with the PIPP/PIPP-R scale up to 30 minutes after the procedure (MD 0.14, 95% CI -0.17 to 0.45; 123 participants, 2 studies; very low-certainty evidence) or one to two hours after the procedure (MD -0.83, 95% CI -2.42 to 0.75; 54 participants, 2 studies; very low-certainty evidence). The evidence is very uncertain about the effect of opioids on episodes of bradycardia (RR 3.19, 95% CI 0.14 to 72.69; 172 participants, 3 studies; very low-certainty evidence). Opioids may result in an increase in episodes of apnea compared to placebo (RR 3.15, 95% CI 1.08 to 9.16; 199 participants, 3 studies; low-certainty evidence): with one study reporting a concerning increase in severe apnea (RR 7.44, 95% CI 0.42 to 132.95; 31 participants, 1 study; very low-certainty). The evidence is very uncertain about the effect of opioids on episodes of hypotension (RR not estimable, risk difference 0.00, 95% CI -0.06 to 0.06; 88 participants, 2 studies; very low-certainty evidence). No studies reported parent satisfaction with care provided in the neonatal intensive care unit (NICU). Opioids compared to non-pharmacological intervention The evidence is very uncertain about the effect of opioids on pain score assessed with the Crying Requires oxygen Increased vital signs Expression Sleep (CRIES) scale during the procedure when compared to facilitated tucking (MD -4.62, 95% CI -6.38 to -2.86; 100 participants, 1 study; very low-certainty evidence) or sensorial stimulation (MD 0.32, 95% CI -1.13 to 1.77; 100 participants, 1 study; very low-certainty evidence). The other main outcomes were not reported. Opioids compared to other analgesics or sedatives The evidence is very uncertain about the effect of opioids on pain score assessed with the PIPP/PIPP-R during the procedure (MD -0.29, 95% CI -1.58 to 1.01; 124 participants, 2 studies; very low-certainty evidence); up to 30 minutes after the procedure (MD -1.10, 95% CI -2.82 to 0.62; 12 participants, 1 study; very low-certainty evidence); and one to two hours after the procedure (MD -0.17, 95% CI -2.22 to 1.88; 12 participants, 1 study; very low-certainty evidence). No studies reported any harms. The evidence is very uncertain about the effect of opioids on episodes of apnea during (RR 3.27, 95% CI 0.85 to 12.58; 124 participants, 2 studies; very low-certainty evidence) and after the procedure (RR 2.71, 95% CI 0.11 to 64.96; 124 participants, 2 studies; very low-certainty evidence) and on hypotension (RR 1.34, 95% CI 0.32 to 5.59; 204 participants, 3 studies; very low-certainty evidence). The other main outcomes were not reported. We identified no studies comparing different opioids (e.g. morphine versus fentanyl) or different routes for administration of the same opioid (e.g. morphine enterally versus morphine intravenously).

AUTHORS' CONCLUSIONS

Compared to placebo, opioids probably reduce pain score assessed with PIPP/PIPP-R scale during the procedure; may reduce NIPS during the procedure; and may result in little to no difference in DAN one to two hours after the procedure. The evidence is very uncertain about the effect of opioids on pain assessed with other pain scores or at different time points. The evidence is very uncertain about the effect of opioids on episodes of bradycardia, hypotension or severe apnea. Opioids may result in an increase in episodes of apnea. No studies reported parent satisfaction with care provided in the NICU. The evidence is very uncertain about the effect of opioids on any outcome when compared to non-pharmacological interventions or to other analgesics. We identified no studies comparing opioids to other opioids or comparing different routes of administration of the same opioid.

Systemic opioid regimens for postoperative pain in neonates

BACKGROUND

Postoperative pain clinical management in neonates has always been a challenging medical issue. Worldwide, several systemic opioid regimens are available for pediatricians, neonatologists, and general practitioners to control pain in neonates undergoing surgical procedures. However, the most effective and safe regimen is still unknown in the current body of literature.

OBJECTIVES

To determine the effects of different regimens of systemic opioid analgesics in neonates submitted to surgery on all-cause mortality, pain, and significant neurodevelopmental disability. Potentially assessed regimens might include: different doses of the same opioid, different routes of administration of the same opioid, continuous infusion versus bolus administration, or 'as needed' administration versus 'as scheduled' administration.

SEARCH METHODS

Searches were conducted in June 2022 using the following databases: Cochrane Central Register of Controlled Trials [CENTRAL], PubMed, and CINAHL. Trial registration records were identified via CENTRAL and an independent search of the ISRCTN registry.

SELECTION CRITERIA

We included randomized controlled trials (RCTs), quasi-randomized, cluster-randomized, and cross-over controlled trials evaluating systemic opioid regimens' effects on postoperative pain in neonates (pre-term or full-term). We considered suitable for inclusion: I) studies evaluating different doses of the same opioid; 2) studies evaluating different routes of administration of the same opioid; 3) studies evaluating the effectiveness of continuous infusion versus bolus infusion; and 4) studies establishing an assessment of an 'as needed' administration versus 'as scheduled' administration.

DATA COLLECTION AND ANALYSIS

According to Cochrane methods, two investigators independently screened retrieved records, extracted data, and appraised the risk of bias. We stratified meta-analysis by the type of intervention: studies evaluating the use of opioids for postoperative pain in neonates through continuous infusion versus bolus infusion and studies assessing the 'as needed' administration versus 'as scheduled' administration. We used the fixed-effect model with risk ratio (RR) for dichotomous data and mean difference (MD), standardized mean difference (SMD), median, and interquartile range (IQR) for continuous data. Finally, we used the GRADEpro approach for primary outcomes to evaluate the quality of the evidence across included studies.

MAIN RESULTS

In this review, we included seven randomized controlled clinical trials (504 infants) from 1996 to 2020. We identified no studies comparing different doses of the same opioid, or different routes. The administration of continuous opioid infusion versus bolus administration of opioids was evaluated in six studies, while one study compared 'as needed' versus 'as scheduled' administration of morphine given by parents or nurses. Overall, the effectiveness of continuous infusion of opioids over bolus infusion as measured by the visual analog scale (MD 0.00, 95% confidence interval (CI) -0.23 to 0.23; 133 participants, 2 studies; I² = 0); or using the COMFORT scale (MD -0.07, 95% CI -0.89 to 0.75; 133 participants, 2 studies; I² = 0), remains unclear due to study designs' limitations, such as the unclear risk of attrition, reporting bias, and imprecision among reported results (very low certainty of the evidence).  None of the included studies reported data on other clinically important outcomes such as all-cause mortality rate during hospitalization, major neurodevelopmental disability, the incidence of severe retinopathy of prematurity or intraventricular hemorrhage, and cognitive- and educational-related outcomes.  AUTHORS' CONCLUSIONS: Limited evidence is available on continuous infusion compared to intermittent boluses of systemic opioids. We are uncertain whether continuous opioid infusion reduces pain compared with intermittent opioid boluses; none of the studies reported the other primary outcomes of this review, i.e. all-cause mortality during initial hospitalization, significant neurodevelopmental disability, or cognitive and educational outcomes among children older than five years old. Only one small study reported on morphine infusion with parent- or nurse-controlled analgesia.

Opioids for procedural pain in neonates

BACKGROUND

Neonates might be exposed to numerous painful procedures due to diagnostic reasons, therapeutic interventions, or surgical procedures. Options for pain management include opioids, non-pharmacological interventions, and other drugs. Morphine, fentanyl, and remifentanil are the opioids most often used in neonates. However, negative impact of opioids on the structure and function of the developing brain has been reported.

OBJECTIVES

To evaluate the benefits and harms of opioids in term or preterm neonates exposed to procedural pain, compared to placebo or no drug, non-pharmacological intervention, other analgesics or sedatives, other opioids, or the same opioid administered by a different route.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search date was December 2021.

SELECTION CRITERIA

We included randomized controlled trials conducted in preterm and term infants of a postmenstrual age (PMA) up to 46 weeks and 0 days exposed to procedural pain where opioids were compared to 1) placebo or no drug; 2) non-pharmacological intervention; 3) other analgesics or sedatives; 4) other opioids; or 5) the same opioid administered by a different route.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were pain assessed with validated methods and any harms. We used a fixed-effect model with risk ratio (RR) for dichotomous data and mean difference (MD) for continuous data, and their confidence intervals (CI). We used GRADE to assess the certainty of the evidence for each outcome.

MAIN RESULTS

We included 13 independent studies (enrolling 823 newborn infants): seven studies compared opioids to no treatment or placebo (the main comparison in this review), two studies to oral sweet solution or non-pharmacological intervention, and five studies (of which two were part of the same study) to other analgesics and sedatives. All studies were performed in a hospital setting. Opioids compared to placebo or no drug Compared to placebo, opioids probably reduce pain score assessed with the Premature Infant Pain Profile (PIPP)/PIPP-Revised (PIPP-R) scale during the procedure (MD -2.58, 95% CI -3.12 to -2.03; 199 participants, 3 studies; moderate-certainty evidence); may reduce Neonatal Infant Pain Scale (NIPS) during the procedure (MD -1.97, 95% CI -2.46 to -1.48; 102 participants, 2 studies; low-certainty evidence); and may result in little to no difference in pain score assessed with the Douleur Aiguë du Nouveau-né (DAN) scale one to two hours after the procedure (MD -0.20, 95% CI -2.21 to 1.81; 42 participants, 1 study; low-certainty evidence). The evidence is very uncertain about the effect of opioids on pain score assessed with the PIPP/PIPP-R scale up to 30 minutes after the procedure (MD 0.14, 95% CI -0.17 to 0.45; 123 participants, 2 studies; very low-certainty evidence) or one to two hours after the procedure (MD -0.83, 95% CI -2.42 to 0.75; 54 participants, 2 studies; very low-certainty evidence). No studies reported any harms. The evidence is very uncertain about the effect of opioids on episodes of bradycardia (RR 3.19, 95% CI 0.14 to 72.69; 172 participants, 3 studies; very low-certainty evidence). Opioids may result in an increase in episodes of apnea compared to placebo (RR 3.15, 95% CI 1.08 to 9.16; 199 participants, 3 studies; low-certainty evidence). The evidence is very uncertain about the effect of opioids on episodes of hypotension (RR not estimable, risk difference 0.00, 95% CI -0.06 to 0.06; 88 participants, 2 studies; very low-certainty evidence). No studies reported parent satisfaction with care provided in the neonatal intensive care unit (NICU). Opioids compared to non-pharmacological intervention The evidence is very uncertain about the effect of opioids on pain score assessed with the Crying Requires oxygen Increased vital signs Expression Sleep (CRIES) scale during the procedure when compared to facilitated tucking (MD -4.62, 95% CI -6.38 to -2.86; 100 participants, 1 study; very low-certainty evidence) or sensorial stimulation (MD 0.32, 95% CI -1.13 to 1.77; 100 participants, 1 study; very low-certainty evidence). The other main outcomes were not reported. Opioids compared to other analgesics or sedatives The evidence is very uncertain about the effect of opioids on pain score assessed with the PIPP/PIPP-R during the procedure (MD -0.29, 95% CI -1.58 to 1.01; 124 participants, 2 studies; very low-certainty evidence); up to 30 minutes after the procedure (MD -1.10, 95% CI -2.82 to 0.62; 12 participants, 1 study; very low-certainty evidence); and one to two hours after the procedure (MD -0.17, 95% CI -2.22 to 1.88; 12 participants, 1 study; very low-certainty evidence). No studies reported any harms. The evidence is very uncertain about the effect of opioids on episodes of apnea during (RR 3.27, 95% CI 0.85 to 12.58; 124 participants, 2 studies; very low-certainty evidence) and after the procedure (RR 2.71, 95% CI 0.11 to 64.96; 124 participants, 2 studies; very low-certainty evidence) and on hypotension (RR 1.34, 95% CI 0.32 to 5.59; 204 participants, 3 studies; very low-certainty evidence). The other main outcomes were not reported. We identified no studies comparing different opioids (e.g. morphine versus fentanyl) or different routes for administration of the same opioid (e.g. morphine enterally versus morphine intravenously).

AUTHORS' CONCLUSIONS

Compared to placebo, opioids probably reduce pain score assessed with PIPP/PIPP-R scale during the procedure; may reduce NIPS during the procedure; and may result in little to no difference in DAN one to two hours after the procedure. The evidence is very uncertain about the effect of opioids on pain assessed with other pain scores or at different time points. No studies reported if any harms occurred. The evidence is very uncertain about the effect of opioids on episodes of bradycardia or hypotension. Opioids may result in an increase in episodes of apnea. No studies reported parent satisfaction with care provided in the NICU. The evidence is very uncertain about the effect of opioids on any outcome when compared to non-pharmacological interventions or to other analgesics. We identified no studies comparing opioids to other opioids or comparing different routes of administration of the same opioid.

Systemic opioids versus other analgesics and sedatives for postoperative pain in neonates

BACKGROUND

Neonates may undergo surgery because of malformations such as diaphragmatic hernia, gastroschisis, congenital heart disease, and hypertrophic pyloric stenosis, or complications of prematurity, such as necrotizing enterocolitis, spontaneous intestinal perforation, and retinopathy of prematurity that require surgical treatment. Options for treatment of postoperative pain include opioids, non-pharmacological interventions, and other drugs. Morphine, fentanyl, and remifentanil are the opioids most often used in neonates. However, negative impact of opioids on the structure and function of the developing brain has been reported. The assessment of the effects of opioids is of utmost importance, especially for neonates in substantial pain during the postoperative period.

OBJECTIVES

To evaluate the benefits and harms of systemic opioid analgesics in neonates who underwent surgery on all-cause mortality, pain, and significant neurodevelopmental disability compared to no intervention, placebo, non-pharmacological interventions, different types of opioids, or other drugs.

SEARCH METHODS

We searched Cochrane CENTRAL, MEDLINE via PubMed and CINAHL in May 2021. We searched the WHO ICTRP, clinicaltrials.gov, and ICTRP trial registries. We searched conference proceedings, and the reference lists of retrieved articles for RCTs and quasi-RCTs.  SELECTION CRITERIA: We included randomized controlled trials (RCTs) conducted in preterm and term infants of a postmenstrual age up to 46 weeks and 0 days with postoperative pain where systemic opioids were compared to 1) placebo or no intervention; 2) non-pharmacological interventions; 3) different types of opioids; or 4) other drugs.  DATA COLLECTION AND ANALYSIS: We used standard Cochrane methods. Our primary outcomes were pain assessed with validated methods, all-cause mortality during initial hospitalization, major neurodevelopmental disability, and cognitive and educational outcomes in children more than five years old. We used the fixed-effect model with risk ratio (RR) and risk difference (RD) for dichotomous data and mean difference (MD) for continuous data. We used GRADE to assess the certainty of evidence for each outcome.

MAIN RESULTS

We included four RCTs enrolling 331 infants in four countries across different continents. Most studies considered patients undergoing large or medium surgical procedures (including major thoracic or abdominal surgery), who potentially required pain control through opioid administration after surgery. The randomized trials did not consider patients undergoing minor surgery (including inguinal hernia repair) and those individuals exposed to opioids before the beginning of the trial. Two RCTs compared opioids with placebo; one fentanyl with tramadol; and one morphine with paracetamol. No meta-analyses could be performed because the included RCTs reported no more than three outcomes within the prespecified comparisons. Certainty of the evidence was very low for all outcomes due to imprecision of the estimates (downgrade by two levels) and study limitations (downgrade by one level).  Comparison 1: opioids versus no treatment or placebo Two trials were included in this comparison, comparing either tramadol or tapentadol with placebo. No data were reported on the following critical outcomes: pain; major neurodevelopmental disability; or cognitive and educational outcomes in children more than five years old. The evidence is very uncertain about the effect of tramadol compared with placebo on all-cause mortality during initial hospitalization (RR 0.32, 95% Confidence Interval (CI) 0.01 to 7.70; RD -0.03, 95% CI -0.10 to 0.05, 71 participants, 1 study; I² = not applicable). No data were reported on: retinopathy of prematurity; or intraventricular hemorrhage.  Comparison 2: opioids versus non-pharmacological interventions No trials were included in this comparison. Comparison 3: head-to-head comparisons of different opioids One trial comparing fentanyl with tramadol was included in this comparison. No data were reported on the following critical outcomes: pain; major neurodevelopmental disability; or cognitive and educational outcomes in children more than five years old. The evidence is very uncertain about the effect of fentanyl compared with tramadol on all-cause mortality during initial hospitalization (RR 0.99, 95% CI 0.59 to 1.64; RD 0.00, 95% CI -0.13 to 0.13, 171 participants, 1 study; I² = not applicable). No data were reported on: retinopathy of prematurity; or intraventricular hemorrhage.  Comparison 4: opioids versus other analgesics and sedatives One trial comparing morphine with paracetamol was included in this comparison. The evidence is very uncertain about the effect of morphine compared with paracetamol on COMFORT pain scores (MD 0.10, 95% CI -0.85 to 1.05; 71 participants, 1 study; I² = not applicable).  No data were reported on the other critical outcomes, i.e. major neurodevelopmental disability; cognitive and educational outcomes in children more than five years old, all-cause mortality during initial hospitalization; retinopathy of prematurity; or intraventricular hemorrhage.

AUTHORS' CONCLUSIONS

Limited evidence is available on opioid administration for postoperative pain in newborn infants compared to either placebo, other opioids, or paracetamol. We are uncertain whether tramadol reduces mortality compared to placebo; none of the studies reported pain scores, major neurodevelopmental disability, cognitive and educational outcomes in children older than five years old, retinopathy of prematurity, or intraventricular hemorrhage. We are uncertain whether fentanyl reduces mortality compared to tramadol; none of the studies reported pain scores, major neurodevelopmental disability, cognitive and educational outcomes in children older than five years old, retinopathy of prematurity, or intraventricular hemorrhage. We are uncertain whether morphine reduces pain compared to paracetamol; none of the studies reported major neurodevelopmental disability, cognitive and educational outcomes in children more than five years old, all-cause mortality during initial hospitalization, retinopathy of prematurity, or intraventricular hemorrhage. We identified no studies comparing opioids versus non-pharmacological interventions.

Early-life exposure to analgesia and 18-month neurodevelopmental outcomes in very preterm infants

BACKGROUND

We assessed variability of analgesic use across three tertiary neonatal intensive care units (NICUs) accounting for early-life pain, quantified as number of invasive procedures. We also determined whether analgesia exposure modifies associations between early-life pain and neurodevelopment.

METHODS

Multicenter prospective study of 276 very preterm infants (born <24-32 weeks' gestational age [GA]). Detailed data of number of invasive procedures and duration of analgesia exposure were collected in initial weeks after birth. Eighteen-month neurodevelopmental assessments were completed in 215 children with Bayley Scales for Infant Development-Third edition.

RESULTS

Multivariable linear regressions revealed significant differences in morphine use across sites, for a given exposure to early-life pain (interaction p < 0.001). Associations between early-life pain and motor scores differed by duration of morphine exposure (interaction p = 0.01); greater early-life pain was associated with poorer motor scores in infants with no or long (>7 days) exposure, but not short exposure (≤7 days).

CONCLUSIONS

Striking cross-site differences in morphine exposure in very preterm infants are observed even when accounting for early-life pain. Negative associations between greater early-life pain and adverse motor outcomes were attenuated in infants with short morphine exposure. These findings emphasize the need for further studies of optimal analgesic approaches in preterm infants.

IMPACT

In very preterm neonates, both early-life exposure to pain and analgesia are associated with adverse neurodevelopment and altered brain maturation, with no clear guidelines for neonatal pain management in this population. We found significant cross-site variability in morphine use across three tertiary neonatal intensive care units in Canada. Morphine use modified associations between early-life pain and motor outcomes. In infants with no or long durations of morphine exposure, greater early-life pain was associated with lower motor scores, this relationship was attenuated in those with short morphine exposure. Further trials of optimal treatment approaches with morphine in preterm infants are warranted.

[Evidence-based guideline for neonatal pain management in China (2023)]

Pain disrupts neonatal vital signs and internal environment homeostasis and affects the recovery process, and recurrent pain stimulation is one of the important risk factors for neurodevelopmental disorders and some chronic diseases. In order to standardize pain management practice in neonatal wards in China and effectively prevent and reduce the adverse effects of pain on the physical and mental development of neonates, National Clinical Research Center for Child Health and Diseases (Children's Hospital of Chongqing Medical University) convened a multidisciplinary panel to formulate the evidence-based guideline for neonatal pain management in China (2023 edition) following the principles and methods for the guideline development issued by the World Health Organization. Based on the best evidence and expert consensus, this guideline gives 26 recommendations for nine clinical issues, i.e., the classification and definition of neonatal pain, common sources of pain, pain assessment principles, pain assessment methods, analgesic principle, non-pharmaceutical analgesic methods, pharmaceutical analgesic methods, parental participation in pain management, and recording methods for pain management, so as to provide medical staff with guidance and a decision-making basis for neonatal pain assessment and analgesia management.

European Consensus Guidelines on the Management of Respiratory Distress Syndrome: 2022 Update

Respiratory distress syndrome (RDS) care pathways evolve slowly as new evidence emerges. We report the sixth version of "European Guidelines for the Management of RDS" by a panel of experienced European neonatologists and an expert perinatal obstetrician based on available literature up to end of 2022. Optimising outcome for babies with RDS includes prediction of risk of preterm delivery, appropriate maternal transfer to a perinatal centre, and appropriate and timely use of antenatal steroids. Evidence-based lung-protective management includes initiation of non-invasive respiratory support from birth, judicious use of oxygen, early surfactant administration, caffeine therapy, and avoidance of intubation and mechanical ventilation where possible. Methods of ongoing non-invasive respiratory support have been further refined and may help reduce chronic lung disease. As technology for delivering mechanical ventilation improves, the risk of causing lung injury should decrease, although minimising time spent on mechanical ventilation by targeted use of postnatal corticosteroids remains essential. The general care of infants with RDS is also reviewed, including emphasis on appropriate cardiovascular support and judicious use of antibiotics as being important determinants of best outcome. We would like to dedicate this guideline to the memory of Professor Henry Halliday who died on November 12, 2022.These updated guidelines contain evidence from recent Cochrane reviews and medical literature since 2019. Strength of evidence supporting recommendations has been evaluated using the GRADE system. There are changes to some of the previous recommendations as well as some changes to the strength of evidence supporting recommendations that have not changed. This guideline has been endorsed by the European Society for Paediatric Research (ESPR) and the Union of European Neonatal and Perinatal Societies (UENPS).

Systemic opioid regimens for postoperative pain in neonates

BACKGROUND

Postoperative pain clinical management in neonates has always been a challenging medical issue. Worldwide, several systemic opioid regimens are available for pediatricians, neonatologists, and general practitioners to control pain in neonates undergoing surgical procedures. However, the most effective and safe regimen is still unknown in the current body of literature.

OBJECTIVES

To determine the effects of different regimens of systemic opioid analgesics in neonates submitted to surgery on all-cause mortality, pain, and significant neurodevelopmental disability. Potentially assessed regimens might include: different doses of the same opioid, different routes of administration of the same opioid, continuous infusion versus bolus administration, or 'as needed' administration versus 'as scheduled' administration.

SEARCH METHODS

Searches were conducted in June 2022 using the following databases: Cochrane Central Register of Controlled Trials [CENTRAL], PubMed, and CINAHL. Trial registration records were identified via CENTRAL and an independent search of the ISRCTN registry.

SELECTION CRITERIA

We included randomized controlled trials (RCTs), quasi-randomized, cluster-randomized, and cross-over controlled trials evaluating systemic opioid regimens' effects on postoperative pain in neonates (pre-term or full-term). We considered suitable for inclusion: I) studies evaluating different doses of the same opioid; 2) studies evaluating different routes of administration of the same opioid; 3) studies evaluating the effectiveness of continuous infusion versus bolus infusion; and 4) studies establishing an assessment of an 'as needed' administration versus 'as scheduled' administration.

DATA COLLECTION AND ANALYSIS

According to Cochrane methods, two investigators independently screened retrieved records, extracted data, and appraised the risk of bias. We stratified meta-analysis by the type of intervention: studies evaluating the use of opioids for postoperative pain in neonates through continuous infusion versus bolus infusion and studies assessing the 'as needed' administration versus 'as scheduled' administration. We used the fixed-effect model with risk ratio (RR) for dichotomous data and mean difference (MD), standardized mean difference (SMD), median, and interquartile range (IQR) for continuous data. Finally, we used the GRADEpro approach for primary outcomes to evaluate the quality of the evidence across included studies.

MAIN RESULTS

In this review, we included seven randomized controlled clinical trials (504 infants) from 1996 to 2020. We identified no studies comparing different doses of the same opioid, or different routes. The administration of continuous opioid infusion versus bolus administration of opioids was evaluated in six studies, while one study compared 'as needed' versus 'as scheduled' administration of morphine given by parents or nurses. Overall, the effectiveness of continuous infusion of opioids over bolus infusion as measured by the visual analog scale (MD 0.00, 95% confidence interval (CI) -0.23 to 0.23; 133 participants, 2 studies; I² = 0); or using the COMFORT scale (MD -0.07, 95% CI -0.89 to 0.75; 133 participants, 2 studies; I² = 0), remains unclear due to study designs' limitations, such as the unclear risk of attrition, reporting bias, and imprecision among reported results (very low certainty of the evidence).  None of the included studies reported data on other clinically important outcomes such as all-cause mortality rate during hospitalization, major neurodevelopmental disability, the incidence of severe retinopathy of prematurity or intraventricular hemorrhage, and cognitive- and educational-related outcomes.  AUTHORS' CONCLUSIONS: Limited evidence is available on continuous infusion compared to intermittent boluses of systemic opioids. We are uncertain whether continuous opioid infusion reduces pain compared with intermittent opioid boluses; none of the studies reported the other primary outcomes of this review, i.e. all-cause mortality during initial hospitalization, significant neurodevelopmental disability, or cognitive and educational outcomes among children older than five years old. Only one small study reported on morphine infusion with parent- or nurse-controlled analgesia.

Effectiveness of Non-Pharmacological Methods, Such as Breastfeeding, to Mitigate Pain in NICU Infants

Neonates do experience pain and its management is necessary in order to prevent long-term, as well as, short-term effects. The most common source of pain in the neonatal intensive care unit (NICU) is caused by medically invasive procedures. NICU patients have to endure trauma, medical adhesive related skin injuries, heel lance, venipuncture and intramuscular injection as well as nasogastric catheterization besides surgery. A cornerstone in pain assessment is the use of scales such as COMFORT, PIPP-R, NIPS and N-PASS. This narrative review provides an up to date account of neonate pain management used in NICUs worldwide focusing on non-pharmacological methods. Non-steroidal anti-inflammatory drugs have well established adverse side effects and opioids are addictive thus pharmacological methods should be avoided if possible at least for mild pain management. Non-pharmacological interventions, particularly breastfeeding and non-nutritive sucking as primary strategies for pain management in neonates are useful strategies to consider. The best non-pharmacological methods are breastfeeding followed by non-nutritive sucking coupled with sucrose sucking. Regrettably most parents used only physical methods and should be trained and involved for best results. Further research in NICU is essential as the developmental knowledge changes and neonate physiology is further uncovered together with its connection to pain.

Frequencies, Modalities, Doses and Duration of Computerized Prescriptions for Sedative, Analgesic, Anesthetic and Paralytic Drugs in Neonates Requiring Intensive Care: A Prospective Pharmacoepidemiologic Cohort Study in 30 French NICUs From 2014 to 2020

Objectives: No consensus exists about the doses of analgesics, sedatives, anesthetics, and paralytics used in critically ill neonates. Large-scale, detailed pharmacoepidemiologic studies of prescription practices are a prerequisite to future research. This study aimed to describe the detailed prescriptions of these drug classes in neonates hospitalized in neonatal intensive care units (NICU) from computerized prescription records and to compare prescriptions by gestational age. Materials and Methods: We included all neonates requiring intensive care in 30 French level III units from 2014 through 2020 with a computerized prescription for an analgesic, sedative, anesthetic, or paralytic agent. We described frequencies of prescription, methods of administration, concomitant drug prescriptions, and dosing regimen, and compared them across gestational ages. Results: Among 65,555 neonates, 29,340 (44.8%) were prescribed at least one analgesic (acetaminophen in 37.2% and opioids in 17.8%), sedative (9.8%), anesthetic (8.5%), and/or paralytic agent (1%). Among preterm infants born before 28 weeks, 3,771/4,283 (88.0%) were prescribed at least one of these agents: 69.7% opioids, 41.2% sedatives, 32.5% anesthetics, and 5.8% paralytics. The most frequently prescribed agents were sufentanil (in 10.3% of neonates) and morphine (in 8.0% of neonates) for opioids, midazolam (9.3%) for sedatives, ketamine (5.7%) and propofol (3.3%) for anesthetics. In most neonates, opioids and sedatives were prescribed as continuous infusion, whereas anesthetics were prescribed as single doses. Opioids, sedatives and paralytics were mostly prescribed in association with another agent. Doses varied significantly by gestational age but within a limited range. Gestational age was inversely related to the frequency, cumulative dose and duration of prescriptions. For example, morphine prescriptions showed median (IQR) cumulative doses of 2601 (848-6750) vs. 934 (434-2679) µg/kg and median (IQR) durations of 7 (3-15) vs. 3 (2-5) days in infants born <28 vs. ≥ 37 weeks of gestation, respectively (p-value<0.001). Conclusion: The prescriptions of analgesic, sedative, anesthetic, or paralytic agent were frequent and often combined in the NICU. Lower gestational age was associated with higher frequencies, longer durations and higher cumulative doses of these prescriptions. Dose-finding studies to determine individualized dosing regimens and studies on long-term neurodevelopmental outcome according to received cumulative doses are required.

Usefulness of two types of pain monitors in newborns treated in NICU, in the opinion of experts: Results of the survey

Pain experienced in the neonatal period has been shown to have serious short- and long-term consequences. It is also known that painkillers have side effects and should not be abused. The basis of proper pain management is assessment of pain, which in newborns is very difficult due to the lack of verbal communication. In these patients, behavioural scales are used to assess pain, but they have numerous shortcomings. For this reason, many newborns treated in the ICU are at risk of pain, so instrumental methods of detecting and assessing the severity of pain are being sought. During three months, seven Polish NICUs conducted research with the use of NIPE and SCA monitors. After this time, the heads of these departments filled in questionnaires regarding their individual opinions on the usefulness of these devices. All respondents found pain monitors useful in the NICU. The NIPE monitor was rated slightly higher, as its usefulness in assessing the effectiveness of analgosedation and in the management of patients in the postoperative period was better rated. The high acceptance of both devices by legal guardians of newborns is noteworthy. It should be stated that in newborns, any way to improve pain monitoring is valuable. In the opinion of Polish experts, pain monitors are useful in NICU. The NIPE monitor was assessed a little higher and was considered useful in the assessment of analgosedation and in postoperative treatment. Pain monitors can provide valuable support for pain assessment in newborns treated in the NICU.

Systemic opioid regimens for postoperative pain in neonates

This is a protocol for a Cochrane Review (intervention). The objectives are as follows:

To determine the effects of different regimens of systemic opioid analgesics in neonates (term or preterm) undergoing surgery, on mortality, pain and major neurodevelopmental disability. These different regimens may include: different doses of the same opioid; different routes of administration of the same opioid; continuous infusion versus bolus administration; or 'as needed' administration versus 'as scheduled' administration.

Opioids for neonates receiving mechanical ventilation

BACKGROUND

Mechanical ventilation is a potentially painful and discomforting intervention widely used in neonatal intensive care units. Newborn babies (neonates) demonstrate increased sensitivity to pain, which may affect clinical and neurodevelopmental outcomes. The use of drugs that reduce pain might be important in improving survival and neurodevelopmental outcomes.

OBJECTIVES

To determine the effect of opioid analgesics (pain-killing drugs derived from opium e.g. morphine), compared to placebo, no drug, or other non-opioid analgesics or sedatives, on pain, duration of mechanical ventilation, mortality, growth and neurodevelopmental outcomes in newborn infants on mechanical ventilation.

SEARCH STRATEGY

Electronic searches included: the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 2, 2007); MEDLINE (1966 to June 2007); EMBASE (1974 to June 2007); and CINAHL (1982 to 2007). Previous reviews and lists of relevant articles were cross-referenced.

SELECTION CRITERIA

Randomised controlled trials or quasi-randomised controlled trials comparing opioids to a control, or to other analgesics or sedatives in newborn infants on mechanical ventilation.

DATA COLLECTION AND ANALYSIS

Data were extracted independently by two review authors. Categorical outcomes were analysed using relative risk and risk difference; and continuous outcomes with weighted mean difference or standardised mean difference. A fixed effect model was used for meta-analysis except where heterogeneity existed, in which case a random effects model was used.

MAIN RESULTS

Thirteen studies on 1505 infants were included. Infants given opioids showed reduced premature infant pain profile (PIPP) scores compared to the control group (weighted mean difference -1.71; 95% confidence interval -3.18 to -0.24). Differences in execution and reporting of trials mean that this meta-analysis should be interpreted with caution. Heterogeneity was significantly high in all analyses of pain, even when lower quality studies were excluded and analysis limited to very preterm newborns. Meta-analyses of mortality, duration of mechanical ventilation, and long and short-term neurodevelopmental outcomes showed no statistically significant differences. Very preterm infants given morphine took significantly longer to reach full enteral feeding than those in control groups (weighted mean difference 2.10 days; 95% confidence interval 0.35 to 3.85). One study compared morphine with a sedative: the treatments showed similar pain scores, but morphine had fewer adverse effects.

AUTHORS' CONCLUSIONS

There is insufficient evidence to recommend routine use of opioids in mechanically ventilated newborns. Opioids should be used selectively, when indicated by clinical judgment and evaluation of pain indicators. If sedation is required, morphine is safer than midazolam. Further research is needed.