[Serious adverse side effects after pupillary dilation in preterm infants]

The effects of mydriatic eye drops on cerebral blood flow and oxygenation in retinopathy of prematurity examinations

Mydriatic eye drops used during retinopathy examination have been associated with cardiovascular, respiratory, and gastrointestinal side effects. The aim of our study was to investigate the effects of the drops used for pupil dilatation on cerebral blood flow and cerebral oxygenation. The study included 62 infants who underwent retinopathy screening exams. Vital signs, heart rate (HR), arterial oxygen saturation (SpO2), and mean arterial pressure (MAP) were recorded. Cerebral oxygenation and middle cerebral artery blood flow velocity were evaluated using near-infrared spectroscopy (NIRS) and Doppler ultrasonography, respectively, and the cerebral metabolic rate of oxygen (CMRO2) was also calculated. The mean gestational age of the infants included was 31.29 ± 1.42 weeks, and the mean birth weight was 1620 ± 265 g. Heart rate was found to be significantly decreased after mydriatic eye drop instillation; however, there were no significant differences regarding blood pressure and oxygen saturation levels (HR: p < 0.001; MAP: p = 0.851; SpO2: p = 0.986, respectively). After instillation while cerebral regional oxygen saturation (rScO2) measurements were significantly decreased at the 60th minute (p = 0.01), no significant difference was found in Vmax and Vmean of MCA before and after mydriatic eye drop instillation (p = 0.755, p = 0.515, respectively). Regarding CMRO2 measurements, we also did not find any statistical difference (p = 0.442).    Conclusion: Our study has shown that although eye drops may affect heart rate and regional cerebral oxygen saturation, they do not alter cerebral blood flow velocities and metabolic rate of oxygen consumption. Current recommendations for mydriatic eye drop use in retinopathy exam appear to be safe. What is Known: • Mydriatic eye drop installation is recommended for pupil dilatation during ROP screening exams. • It's known that mydriatics used in ROP examination have affects on the vital signs, cerebral oxygenation and blood flow. What is New: • This is the first study evaluating the changes in cerebral oxygenation and blood flow velocity after mydriatic drop instillation using NIRS and Doppler US concomitantly. • While the eye drops may affect heart rate and regional cerebral oxygen saturation, they do not alter cerebral blood flow velocities and metabolic rate of oxygen consumption.

Acute drug reaction to phenylephrine and tropicamide collyrium in a late-preterm newborn: a case report

Background

Collyrium administration is a common procedure in the neonatal ward, both in preterm and at term babies. Various molecules are used to induce mydriasis and cycloplegia: among them, phenylephrine and tropicamide are the most popular, and their administration is generally considered safe.

Case presentation

A 35 + 2 weeks-old, 2510 g, well-appearing male newborn required an ophthalmologic evaluation after a doubtful red reflex test. A collyrium with 1% phenylephrine and 0.95% tropicamide was administered prior to the consult, one drop per eye. Two minutes after the administration, the baby developed a severe apnea that required tactile stimulation. Moreover, the area around his eyes became visibly pale. Three minutes later, the baby became severely bradycardic (59 bpm), but remained in good general condition, so that resuscitation maneuvers were not required. Bradycardia lasted for almost three hours and then gradually resolved.

Conclusions

Cardiopulmonary manifestations, such as bradycardia and even cardiopulmonary arrest, are severe complications that can happen after phenylephrine collyrium administration in preterm newborns. However, they have been described in babies below 1500 g or with concurrent respiratory manifestations. Our patient, on the other hand, was late preterm, and never required a ventilatory support prior to the collyrium administration. Practitioners who deal with premature babies, even if late preterm, must be aware of these possible complications and administer phenylephrine collyrium carefully, where cardiopulmonary resuscitation equipment and personnel are available.

Retinopathy of Prematurity Screening Examination and Changes in Vital Signs

BACKGROUND AND OBJECTIVE

Dilation and examination during retinopathy of prematurity (ROP) screening can cause systemic complications and even life-threatening adverse events (AEs). The main objective of this study is to assess the prevalence and significance of AEs and changes in vital signs during ROP screenings, and to correlate birth weight, gestational age, and length of exam as possible predictors of these changes.

PATIENTS AND METHODS

This is a prospective, observational study that includes 1,360 screening exams from 680 premature infants in two neonatal intensive care units. Systolic blood pressure, diastolic blood pressure, heart rate, respiratory rate, and oxygen saturation were monitored from the time that dilating drops were administered until 4 hours after the examination was completed. Any clinical deterioration or complication was documented.

RESULTS

Of 1,360 infant screening exams, 153 (11%) screening exams resulted in at least one change in vital sign that alerted the monitor. There was one serious AE requiring bag valve mask resuscitation 30 minutes after dilating drops were placed. Gestational age, birth weight, and length of ROP exam were not significant predictors of AEs. There were statistically significant changes when comparing pre- and post-vital signs following dilation and funduscopy exam.

CONCLUSIONS

Although ROP screening exams are essential for at-risk neonates, mydriatic drops and retinal exams can result in changes to vital signs and AEs. It is important to closely monitor neonates during these examinations. [Ophthalmic Surg Lasers Imaging Retina. 2021;52:458-463.].

Ophthalmic Insert versus Eye Drops for Mydriasis in Neonates: A Randomized Clinical Trial

BACKGROUND

Eye drop treatment routinely used to obtain mydriasis prior to fundoscopy in neonates requires repeated instillations of mydriatic agents that can lead to systemic side effects.

OBJECTIVES

The aim of this study was to compare the mydriatic efficacy and tolerance of administration of phenylephrine and tropicamide via the ophthalmic insert Mydriasert® versus standard eye drop treatment in neonates.

METHODS

In this prospective, single-blinded, noninferiority study, 80 hospitalized neonates (age < 18 months) requiring bilateral fundus examination were randomized to receive eye drops (repeated instillations of 2.5% phenylephrine and 0.5% tropicamide) or the insert. The primary outcome was mydriasis suitable for fundoscopy 75 min after mydriatic agent introduction (T75).

RESULTS

Mydriasis was successfully achieved in both eyes at T75 in 97.5% (n = 39/40) of the insert group patients versus 90% (n = 36/40) receiving eye drops (between-group difference 7.5%, demonstrating noninferiority). Mydriasis remained stable in 60.0% of patients (n = 24/40) in the insert group versus 15% (n = 6/40) in the eye drop group (p < 0.0001). The insert group required fewer nursing interventions than the eye drop group (p = 0.0001). Mean blood pressure were significantly higher in the insert versus the eye drop group (p < 0.0001 and p = 0.0003, respectively); mean heart rate was not significantly different between the groups (p = 0.37). In the insert group, 2 patients reported an adverse event (bradycardia, n = 1, and gastroesophageal reflux, n = 1; both appeared to be related to neonate pathology).

CONCLUSIONS

The degree of mydriasis achieved with Mydriasert® was noninferior to that obtained with eye drops. The insert appears to be safe to use in neonates without a history of increased vagal tone or gastrointestinal reflux.

Drug-induced mydriasis in infants born at different gestation terms

Background. At the present time, the problem of choice of eye drops to achieve adequate mydriasis with minimal side effects for retinopathy of prematurity screening remains an urgent challenge. Purpose. To estimate the clinical efficacy of combination mydriatic eye drops Fenicamide in infants born at different gestation terms. Materials and methods. Under observation, there were 75 newborns (150 eyes) and babies aged from 1 day to 3 months (average, 38.2 ± 32.2 days). Patients were distributed into 3 groups depending on gestational age: group 1 consisted of 25 full-term infants; group 2 – of 25 premature babies, and group 3 – of 25 extremely preterm infants. To achieve mydriasis, 1 drop of combination eye drops (5% phenylephrine and 0.8% tropicamide) was instilled. Dynamics of pupil diameter change in each group of patients was registered within 4 hours, and side effects were recorded within 24 hours. The quality of fundus visualization was estimated using a pediatric retinal camera RetCam 3. Results. Maximal pupil dilation (average, 6.5 ± 0.5 mm) was reached to 60 ± 14 min after instillation on average; pupil remained dilated within 1 hour, its diameter became normal in 4 hours. Mydriasis varied from 5.9 mm in extremely premature infants to 7 mm in the full-term newborns (p > 0.05), and allowed a full and high quality examination of the fundus in all patients, including the visualization of peripheral zones of the retina for retinopathy of prematurity screening. It was established that drug side effects were absent in 76% (57) of infants, they were present in 24% (18) of infants, mostly as local reaction. Conclusion. Fenicamide eye drops are an effective mydriatic medication, with a convenient instillation regimen, have minimal side effects, and can be recommended for retinopathy of prematurity screening and monitoring.

Non-invasive assessment of cerebral oxygenation: A comparison of retinal and transcranial oximetry

BACKGROUND

To investigate the correlation between cerebral (SO2-transcranial), retinal arterial (SaO2-retinal) and venous (SvO2-retinal) oxygen saturation as measured by near-infrared spectroscopy (NIRS) and retinal oximetry respectively.

METHODS

Paired retinal and cerebral oxygen saturation measurements were performed in healthy volunteers. Arterial and venous retinal oxygen saturation and diameter were measured using a non-invasive spectrophotometric retinal oximeter. Cerebral oxygen saturation was measured using near-infrared spectroscopy. Correlations between SO2-transcranial and retinal oxygen saturation and diameter measurements were assessed using Pearson correlation coefficients. Lin's concordance correlation coefficient (CCC) and Bland-Altman analysis were performed to evaluate the agreement between SO2-transcranial as measured by NIRS and as estimated using a fixed arterial:venous ratio as 0.3 x SaO2-retinal + 0.7 x SvO2-retinal. The individual relative weight of SaO2-retinal and SvO2-retinal to obtain the measured SO2-transcranial was calculated for all subjects.

RESULTS

Twenty-one healthy individuals aged 26.4 ± 2.2 years were analyzed. SO2-transcranial was positively correlated with both SaO2-retinal and SvO2-retinal (r = 0.44, p = 0.045 and r = 0.43, p = 0.049 respectively) and negatively correlated with retinal venous diameter (r = -0.51, p = 0.017). Estimated SO2-transcranial based on retinal oximetry showed a tolerance interval of (-13.70 to 14.72) and CCC of 0.46 (95% confidence interval: 0.05 to 0.73) with measured SO2-transcranial. The average relative weights of SaO2-retinal and SvO2-retinal to obtain SO2-transcranial were 0.31 ± 0.11 and 0.69 ± 0.11, respectively.

CONCLUSION

This is the first study to show the correlation between retinal and cerebral oxygen saturation, measured by NIRS and retinal oximetry. The average relative weight of arterial and venous retinal oxygen saturation to obtain the measured transcranial oxygen saturation as measured by NIRS, approximates the established arterial:venous ratio of 30:70 closely, but shows substantial inter-individual variation. These findings provide a proof of concept for the role of retinal oximetry in evaluating cerebral oxygenation.

Combination of 5% phenylephrine and 0.5% tropicamide eyedrops for pupil dilation in neonates is twice as effective as 0.5% tropicamide eyedrops alone

PURPOSE

Comparison of the efficacy of tropicamide eyedrops to the combination of 0.5% tropicamide and 5% phenylephrine eyedrops in order to achieve a proper dilation in premature infants undergoing screening for retinopathy of prematurity.

METHODS

A prospective, randomized, double-blind study was conducted to compare the efficacy of two mydriatic regimens: one regimen consisting of three drops of 0.5% tropicamide (TTT regimen), the other regimen consisting of one drop of 5% phenylephrine and two drops of 0.5% tropicamide (PTT regimen). Thirty premature infants were enrolled and received both mydriatic regimens: one regimen in each eye. Outcomes were pupil dilation evaluated by the percentage of pupil diameter over cornea diameter, the percentage of pupil surface over cornea surface and the quality of the eye fundus examination.

RESULTS

The percentage of pupil diameter over cornea diameter was 47.3% (±8.7) with the TTT regimen and 65.9% (±8.8) with the PTT regimen (p < 0.0001). The percentage of pupil surface over cornea surface was 23.1% (±8.3) with the TTT regimen and 43.8% (±7.3) with the PTT regimen (p < 0.0001). Thus, the pupil surface area was 1.9 times greater with the PTT than with the TTT regimen. Visualization of the retinal periphery was possible for 30 of 30 eyes dilated with the PTT regimen and for 16 of 30 eyes dilated with the TTT regimen (p < 0.0001).

CONCLUSION

The dilated pupil surface area for the combination of 5% phenylephrine and 0.5% tropicamide was almost twice that for 0.5% tropicamide eyedrops alone and provided significantly superior quality of the eye fundus examination.