Mydriatic effect of anticholinergic drugs used during reversal of nondepolarizing muscle relaxants

The effect of atropine used in dobutamine stress echocardiography on pupil diameter

BACKGROUND

The use of atropine during dobutamine stress echocardiography (DSE) is contraindicated in persons with narrow angle glaucoma though there is limited evidence that low doses of intravenous atropine do not cause pupillary dilation.

OBJECTIVE

The aim of this study is to investigate whether atropine when administered in persons without glaucoma during dobutamine stress echocardiography causes pupillary dilation.

METHODS AND RESULTS

Out of 144 patients without a history of glaucoma referred for DSE for clinical indications, 105 patients received intravenous atropine doses ranging from 0.1 mg to 1.25 mg (most patients received 0.25-0.75 mg). Pupil diameter of both eyes was measured under the same light conditions before and after the DSE using a CP-30 Optical Digital PD Ruler. For the total of 210 examined eyes pupil diameter remained unaltered after each DSE test (3.65 ± 0.799 mm before vs 3.63 ± 0.766 mm after, p = .737). Similarly, pupil diameter remained unchanged when left and right eyes were assessed separately (right eye: 3.770 ± 0.812 before vs 3.752 ± 0.745 mm after, p = .821 and left eye: 3.521 ± 0.770 before vs 3.499 ± 0.770 mm after, p = .806). Diameter of right and left pupil were also unaltered after grouping patients by sex and iris pigmentation. Age, weight, atropine dose and propranolol dose were not correlated with changes in pupil diameter.

CONCLUSION

Intravenous atropine in usual doses administered in DSE does not cause mydriasis in adults without glaucoma. Future studies need to confirm our findings and expand the investigation regarding safety of atropine use during DSE in patients with narrow angle glaucoma.

Pupillometry in perioperative medicine: a narrative review

PURPOSE

Pupillometry is a technique for objective quantification of nociception that takes into account the central processing of noxious stimuli and its sympathetic response. This narrative review provides an overview of the physiology of the pupil, the principles of pupillometry, and its potential application in the perioperative environment, especially in nociception monitoring and quantifying responses to opioids.

SOURCE

Relevant articles, including reports of original investigation, review articles, and meta-analyses were identified from searches of PubMed and Google Scholar databases. Articles that described pupillary physiology and pupillometry, along with original research reports of the application of pupillometry in perioperative and critical care environment were used to synthesize a narrative review.

PRINCIPAL FINDINGS

Pupillometry is emerging as an objective measure of nociception, especially in patients under general anesthesia, children, non-verbal patients, and critically ill patients who cannot effectively communicate ongoing pain. Portable automated pupillometers have made accurate quantification of pupillary reflexes, including light reflex and dilatation reflex, possible. This technique has been successfully studied in the perioperative setting for a number of applications, including quantification of nociception, response to analgesia, and assessing efficacy of regional blocks. Pupillary oscillations have shown promise in assessing central opioid effects. Pupillometers can also accurately quantify light reflexes during the neurologic evaluation of critically ill patients.

CONCLUSIONS

Pupillometry is an easy to use non-invasive bedside technique to quantify nociception and monitor opioid effects. It has the potential to personalize pain management in perioperative and intensive care unit environments. Additional studies are needed to further understand the utility of pupillometry in this context.

Glycopyrrolate induced bilateral angle closure glaucoma after cervical spine surgery

To report a case of bilateral acute angle closure glaucoma (AACG) that occurred after cervical spine surgery with the use of glycopyrolate. A 59-year-old male who presented with severe bilateral bifrontal headache and eye pain that started 12 h postextubation from a cervical spine surgery. Neostigmine 0.05 mg/kg (4.5 mg) and glycopyrrolate 0.01 mg/kg (0.9 mg) were used as muscle relaxant reversals at the end of the surgery. Ophthalmic examination revealed he had bilateral AACG with plateau iris syndrome that was treated medically along with laser iridotomies. Thorough examination of anterior chamber should be performed preoperatively on all patients undergoing surgeries in the prone position and receiving mydriatic agents under general anesthesia.

Pharmacological and environmental factors in primary angle-closure glaucoma

INTRODUCTION OR BACKGROUND

A large number of drug classes have now been reported to provoke angle closure in high-risk individuals. The mechanism of action can be generalized into three main categories: sympathomimetic, parasympatholytic and idiosyndratic reactions.

SOURCES OF DATA

This review of the ophthalmic literature provides a clinical summary of primary angle-closure glaucoma (PACG) and its management.

AREAS OF AGREEMENT

External stimuli (pharmacological and environmental) may induce acute, and more often, asymptomatic angle closure, which carries a significant risk of glaucoma.

GROWING POINTS

Whenever in doubt, patients at risk of PACG who are starting on drug therapy known to provoke angle closure or aggravate the condition should be referred for detailed gonioscopic examination of the anterior chamber by an ophthalmologist. AREAS FOR DEVELOPING RESEARCH: The use of new imaging methods such as anterior segment optical coherence tomography to assess the presence or risk of angle closure is gaining popularity, and may offer a more rapid method of identifying people who are at risk of sight loss from angle-closure glaucoma precipitated by non-ophthalmological medication.

Bilateral angle closure glaucoma following general anesthesia

Although unilateral angle closure glaucoma is quite common, simultaneous bilateral acute angle closure is very rare and is usually induced by an external cause. General anesthesia is a triggering factor for acute angle closure glaucoma. We report two cases of simultaneous bilateral angle closure glaucoma following non-ocular surgery under general anesthesia. One patient had cholecystectomy, the other craniotomy for tumor resection. In the postoperative period following general anesthesia, any patient at risk for angle closure glaucoma should be followed closely; patients with periorbital pain and visual symptoms should be examined for angle closure glaucoma attack in both eyes.

Angle closure glaucoma complicating systemic atropine use in the cardiac catheterization laboratory

Atropine may precipitate angle closure glaucoma in those predisposed to the disorder. Previously reported cases demonstrate the frequent misdiagnosis of acute glaucoma as conjunctivitis. Resultant delays in treatment can lead to vision loss. The present case describes a 66-yr-old man who developed acute angle closure glaucoma after receiving atropine during a coronary angioplasty produce. Clinicians who utilize atropine should be aware of the possibility of precipitating angle closure glaucoma and the predisposing factors, signs, and symptoms to facilitate prompt diagnosis and treatment of this disorder.

Parenteral anticholinergics in dogs with normal and elevated intraocular pressure

Dogs given parenteral anticholinergic drugs have been thought to be at risk for development or exacerbation of elevated intraocular pressure (IOP). In a randomized, blinded, placebo-controlled study, we evaluated the effect of intramuscular glycopyrrolate (0.01 mg/kg) on pupil diameter and IOP in unanesthetized normal dogs. Treatment with glycopyrrolate did not change pupil diameter or IOP from baseline, nor were there differences between glycopyrrolate and saline-treated (control) dogs. In addition, the authors retrospectively reviewed the medical records of 2,828 dogs undergoing general anesthesia between April 1987 and September 1990 to determine if there was an association between parenteral anticholinergic medication and postanesthetic elevation in IOP. The authors also determined the frequency of bradycardia requiring anticholinergic therapy during anesthesia in dogs with glaucoma. Of the 2,828 cases reviewed, the records of 46 dogs coded for glaucoma were examined in detail. The 46 dogs underwent 62 episodes of anesthesia, with 23 episodes including exposure to an anticholinergic drug. An increase in IOP from preanesthetic to postanesthetic measurement occurred in three dogs. One of these dogs received anticholinergic medication for bradycardia during anesthesia. The postanesthetic elevation in IOP in this dog was probably not drug related. Preanesthetic anticholinergic administration did not affect the incidence of anticholinergic administration for bradycardia during the anesthetic episode. Anticholinergic therapy during anesthesia was more frequent when the preanesthetic medication included an opiate drug. These studies do not indicate an association between parenteral anticholinergic administration and elevations in IOP.