Pupillary abnormalities in non-selected critically ill patients: an observational study

Isolated reversible mydriasis was associated with the use of nebulized ipratropium bromide: a case series using quantitative pupilometer in Korea

BACKGROUND

Abnormal pupillary reactivity is a neurological emergency requiring prompt evaluation to identify its underlying causes. Although isolated unilateral mydriasis without accompanying neurological abnormalities is rare, it has occasionally been associated with nebulizer use. We aimed to quantitatively assess pupillary changes using a pupillometer in cases of isolated mydriasis, which has not been described in previous studies.

METHODS

We retrospectively analyzed patients who developed unilateral mydriasis after using an ipratropium bromide nebulizer using a prospectively collected database in the intensive care unit (ICU) between April 2019 and August 2020. An automated pupillometer (NPi-100 or NPi-200) was used for quantitative pupillary assessment. The Neurological Pupil index (NPi) value at the time of unilateral mydriasis was assessed, and the latency before and after the application of the ipratropium bromide nebulizer was measured.

RESULTS

Five patients with isolated mydriasis were identified (mean age, 68 years; male, 60.0%), none of whom had neurological abnormalities other than pupillary light reflex abnormalities. A quantitative pupillometer examination revealed that the affected pupil was larger (5.67 mm vs. 3.20 mm) and had lower NPi values (0.60 vs. 3.40) than the unaffected side. These abnormalities resolved spontaneously without treatment (pupil size, 3.40 mm; NPi, 3.90). The affected pupil had a prolonged latency of 0.38 seconds (vs. 0.28 seconds), which improved to 0.30 seconds with the resolution of the anisocoria.

CONCLUSIONS

In the ICU setting, it is important to keep in mind the ipratropium bromide nebulizer as the benign cause of unilateral mydriasis. Further, an automated pupilometer may be a useful tool for evaluating unilateral mydriasis.

Prognostic role of automatic pupillometry in sepsis: a retrospective study

BACKGROUND

Sepsis-associated brain dysfunction is a frequent disorder in septic patients and has a multifactorial pathophysiology. Cholinergic pathways and brainstem dysfunction may result in pupillary alterations. The aim of this study was to evaluate whether early assessment of the Neurological Pupil Index (NPiTM) derived from an automated pupillometry could predict mortality in critically ill septic patients.

METHODS

Retrospective cohort study of adult critically ill septic patients admitted to the intensive care unit of an University Hospital; patients with acute or known brain damage were excluded. The severity of the patients was assessed by the daily Sequential Organ Failure Assessment score and the SOFAmax (i.e. highest SOFA score during the first 5 days) was computed. The worst NPi (i.e. lowest value from one eye) was collected daily and then computed over the first 5 days of assessment. Mortality was assessed at hospital discharge.

RESULTS

A total of 75 patients were included over the study period (median age 67 [53-75] years and median SOFA score at admission 10 [8-12]); 64 (85%) presented septic shock; 48 (64%) died at hospital discharge. The worst NPi during the first 5 days of sepsis was significantly lower in non-survivors compared to survivors (4.4 [3.6-4.6] vs. 4.5 [4.2-4.7]; p=0.042). The worst NPi was also significantly lower in high severity group (i.e. SOFAmax≥12) when compared to others (4.4 [3.2- 4.5] vs 4.5 [4.0-4.7] p=0.01). However, in the multivariate analyses, the NPi value was not independently associated with in-hospital mortality or high SOFAmax.

CONCLUSIONS

In this study, no independent prognostic role of NPi was observed in septic patients. Further larger prospective studies are needed to better evaluate the role of automated pupillometry in this setting.

Quantitative assessments of pupillary light reflexes in hospital-onset unresponsiveness

BACKGROUND

Patients who develop hospital-onset unresponsiveness should be promptly managed in order to avoid clinical deterioration. Pupillary examination through pupillary light reflex is the gold standard method in the initial evaluation of unresponsive patients. However, the current method of shining light and subjective description often shows poor reliability. The objective of this study is to explore whether a quantitative measurement of pupillary light reflexes is useful in detecting brain herniation syndrome and predicting neurological outcomes in patients who developed hospital-onset unresponsiveness after admission for non-neurological reasons.

METHODS

This was a registry-based observational study on patients who activated the neurological rapid response team at Asan Medical Center (Seoul, Korea). Hospital-onset unresponsiveness was defined as a newly developed unresponsive state as assessed by the ACDU (Alert, Confused, Drowsy, and Unresponsive) scale during the hospital stay. Demographics, comorbidities, pupillometry parameters including Neurological Pupil index, brain herniation syndrome, in-hospital mortality, and modified Rankin Scale at 3-months were analyzed.

RESULTS

In 214 consecutive patients with hospital-onset unresponsiveness, 37 (17%) had brain herniation syndrome. The optimal cut-off value of Neurological Pupil index for detecting brain herniation syndrome was < 1.6 (specificity, 91% [95% confidence interval (CI) = 86-95]; sensitivity, 49% [95% CI = 32-66]). The in-hospital mortality rate was 28% (59/214); the Neurological Pupil index was negatively associated with in-hospital mortality after adjustments for the presence of brain herniation syndrome (adjusted odds ratio = 0.77, 95% CI = 0.62-0.96). Poor neurological outcomes (modified Rankin Scale ≥4) at 3 months was observed in 76% (152/201) of the patients; the Neurological Pupil index was negatively associated with poor neurological outcomes after adjustments for clinical variables (adjusted odds ratio = 0.67, 95% CI = 0.49-0.90).

CONCLUSIONS

Quantitative measurements of pupillary light reflexes may be useful for early detection of potentially life-threatening neurological conditions in patients with hospital-onset unresponsiveness.

Prognostic value of automated pupillometry: an unselected cohort from a cardiac intensive care unit

Background:

Patients admitted to a cardiac intensive care unit are often unconscious with uncertain prognosis. Automated infrared pupillometry for neurological assessment in the intensive care unit may provide early prognostic information. This study aimed to determine the prognostic value of automated pupillometry in different subgroups of patients in a cardiac intensive care unit with 30-day mortality as the primary endpoint and neurological outcome as the secondary endpoint.

Methods:

A total of 221 comatose patients were divided into three groups: out-of-hospital cardiac arrest, in-hospital cardiac arrest and others (i.e. patients with cardiac diagnoses other than cardiac arrest). Automated pupillometry was serially performed until discharge or death and pupil measurements were analysed using the neurological pupil index algorithm. We applied receiver operating characteristic curves in univariable and multivariable logistic regression models and a calculated Youden index identified neurological pupil index cut-off values at different specificities.

Results:

In out-of-hospital cardiac arrest patients higher neurological pupil index values were independently associated with lower 30-day mortality. The univariable model for 30-day mortality had an area under the curve of 0.87 and the multivariable model achieved an area under the curve of 0.94. The Youden index identified a neurological pupil index cut-off in out-of-hospital cardiac arrest patients of 2.40 for a specificity of 100%. For patients with in-hospital cardiac arrest and other cardiac diagnoses, we found no association between neurological pupil index values and 30-day mortality, and the univariable models showed poor predictive values.

Conclusion:

Automated infrared pupillometry has promising predictive value after out-of-hospital cardiac arrest, but poor predictive value in patients with in-hospital cardiac arrest or cardiac diagnoses unrelated to cardiac arrest. Our data suggest a possible neurological pupil index cut-off of 2.40 for poor outcome in out-of-hospital cardiac arrest patients.

Feasibility study of a smartphone pupillometer and evaluation of its accuracy

Measurement of pupillary characteristics, such as pupillary unrest in ambient light, and reflex dilation have been shown to be useful in a variety of clinical situations. Dedicated pupillometers typically capture images in the near-infrared to allow imaging in both light and darkness. However, because a subset of pupillary measurements can be acquired with levels of visible light suitable for conventional cameras, it is theoretically possible to capture data using general purpose cameras and computing devices such as those found on smartphones. Here we describe the development of a smartphone-based pupillometer and compare its performance with a commercial pupillometer. Smartphone pupillometry software was developed and then compared with a commercial pupillometer by performing simultaneous scans in both eyes, using the smartphone pupillometer and a commercial pupillometer. The raw scans were compared, as well as a selected pupillary index: pupillary unrest in ambient light. In 77% of the scans the software was able to successfully identify the pupil and iris. The raw data as well as calculated values of pupillary unrest in ambient light were in clinically acceptable levels of agreement; Bland-Altman analysis of raw pupil measurements yielded a 95% confidence interval of 0.26 mm. In certain situations a smartphone pupillometer may be an appropriate alternative to a commercial pupillometer.

Static and dynamic pupil characteristics in pseudoexfoliation syndrome and glaucoma

BACKGROUND

To compare the static and dynamic pupillometry measurements in patients with pseudoexfoliation syndrome (PES), patients with pseudoexfoliation glaucoma (PEG) and age-matched healthy subjects using an automatic quantitative pupillometry system.

METHODS

This prospective, cross-sectional study consisted of 40 patients with PES, 30 patients with PEG and 43 control subjects. Static pupillometry measurements including scotopic pupil diameter, mesopic pupil diameter, low photopic pupil diameter, and high photopic pupil diameter were undertaken. Subsequently, dynamic pupillometry measurements including resting diameter, amplitude of pupil contraction, latency of pupil contraction, duration of pupil contraction, velocity of pupil contraction, latency of pupil dilation, duration of pupil dilation, and velocity of pupil dilation were undertaken. These measurements were compared between the groups.

RESULTS

The scotopic, mesopic, and low photopic pupil diameter values were statistically significantly lower in patients with PES and PEG compared with controls (p < 0.001). However, these parameters were similar between the patients with PES and PEG (p > 0.05). The mean values of high photopic pupil diameter were similar within all groups (p = 0.54). The amplitude of pupil contraction values of the patients with PEG was statistically significantly lower than the patients with PES and the controls (p < 0.05). Patients with PES also had significantly lower amplitude of pupil contraction values compared with controls (p < 0.001). Additionally, the velocity of pupil contraction values was statistically significantly higher in control subjects when compared to the patients with PES and PEG (p < 0.05).

CONCLUSION

This study demonstrated that accumulation of pseudoexfoliative material can cause alterations in static and dynamic pupillary characteristics and the progression from PES to PEG may be associated with reduced amplitude of pupil contraction values.

Interrater reliability in pupillary assessment among intensive care nurses

BACKGROUND

Pupillary abnormalities are a common and reliable finding of brain herniation, ischaemia, and acute brain injury in critically ill patients. Reliable pupil assessment is a vital evaluation in diagnostic and therapeutic procedures for neurocritical patients.

AIM

To evaluate inter-rater reliability of pupillary assessment among intensive care.

METHODS

In this prospective, blind observational study, intensive care nurses and two researchers evaluated the pupil size, reactivity and symmetry of 200 patients with neurosurgery or neurological diseases. A total of 200 pupillary measurement sets were completed independently and blindly.

RESULTS

Three observers -two researchers and the nurse- found fair-to-good and excellent agreements in initial pupil size evaluations of right and left pupils, respectively (ICC = 0.70, 95%; ICC = 0.75, 95%). In patients with pupil size ≥4 mm, the observers found fair-to-good agreements in both right and left pupil initial size measurements (ICC = 0.52; ICC = 0.65). Agreement in pupil symmetry was moderated (K = 0.58), and reactivity was near perfect (K = 0.89) between the three observers.

CONCLUSION

Although the two researchers found near perfect agreement in pupil size, symmetry and reactivity assessment, two researchers and the nurse found moderate agreement in pupil symmetry and fair-to-good agreement in pre- and post-light stimulation pupil size.

Evaluation of static and dynamic pupil characteristics in hyperopic anisometropic amblyopia

PURPOSE

The aim of this study is to perform a comparison of static and dynamic pupillometry measurements in patients with hyperopic anisometropic amblyopia and age-matched controls.

METHODS

This prospective cross-sectional study consisted of 38 patients with hyperopic anisometropic amblyopia and 80 control subjects. A quantitative pupillometry system was used to evaluate the pupil characteristics of higher hyperopic eyes (Group 1), the fellow eyes (Group 2), and healthy eyes (Group 3). Static pupillometry measurements were taken including scotopic pupil diameter, mesopic pupil diameter, low-photopic pupil diameter, and high-photopic pupil diameter. Subsequently, dynamic pupillometry measurements were taken including resting diameter, amplitude of pupil contraction, latency of pupil contraction, duration of pupil contraction, velocity of pupil contraction, latency of pupil dilation, duration of pupil dilation, and velocity of pupil dilation.

RESULTS

Groups 1 and 2 had statistically significantly lower scotopic and high-photopic pupil diameter values compared with Group 3 (p < 0.05). The amplitude of pupil contraction values were also statistically significantly lower in Groups 1 and 2 compared with Group 3 (p = 0.001 and p = 0.003). However, there were no significant differences between the study and the control eyes with respect to mesopic and high-photopic pupil diameter, resting diameter, latency of pupil contraction, duration of pupil contraction, velocity of pupil contraction, latency of pupil dilation, duration of pupil dilation, and velocity of pupil dilation values (p > 0.05, for all).

CONCLUSION

Static and dynamic pupil characteristics of higher hyperopic eyes and their fellow eyes are similar. This may support that amblyopia is not a monocular disorder, but can affect both eyes.

Pharmacologic anisocoria due to nebulized ipratropium bromide: A diagnostic challenge

Anisocoria may be physiological or seen in fatal conditions, such as intracranial hemorrhage. Newly developing anisocoria may cause confusion and diagnostic difficulty in the emergency department (ED). A 35-year-old female was admitted to the ED with an asthma attack and dyspnea. On examination, the patient was observed to have bilateral rhonchi and was treated with nebulized albuterol (salbutamol) and ipratropium bromide. After the treatment, the dyspnea improved, and mydriasis developed in the left eye (left pupil diameter 9 mm, right 4 mm). An examination revealed that the left pupil was dilated and unreactive to light, but there was no neurological finding. Afterwards, the patient reported that, during the treatment, some aerosol had leaked from the left side of the mask and may have come into contact with her left eye. Given this information, a pilocarpine test was performed, and the patient was diagnosed with pharmacologic anisocoria. The pupil returned to normal within 24 h. Ipratropium bromide is a drug frequently used in patients presenting to the ED with dyspnea. During treatment, nebulized ipratropium may leak from the edge of the facial mask into the ipsilateral eye and may cause mydriasis. A pilocarpine test can be used to differentiate pharmacological anisocoria from other causes, such as third nerve palsy and Adie's pupil. Through the awareness of emergency physicians and the use of the pilocarpine test, a diagnosis can be made without engaging in time-consuming and costly analyses. In addition, this complication can be prevented using masks that better fit the face, as well as protective goggles or eye patches, during treatment.