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Biomedical subjects

R W Arnold

Publications and source records attributed to R W Arnold.

At least 19 recordsLinked to original sources
PubMed2001

Vision loss associated with a stiff neck complicating strabismus surgery.

An exotropic 60 year old suffered a scleral-choroidal penetration and vitreous hemorrhage during and after strabismus surgery on a highly myopic eye when her anesthetic airway management was complicated by her previously asymptomatic and unrecognized rigid cervical spine which placed both the surgeon and the anesthetist in disadvantaged positions both physically and medically. Restoration of vision and binocularity ultimately required vitrectomy and intraocular lens implantation.

Blindness↗
PubMed1999

Hypobaric ocular trauma from a Popper.

We have observed 3 cases of ocular trauma in children that were caused by an atypical, hypobaric mechanism induced by a toy called a Popper. When we initially notified the United States Consumer Product Safety Commission in 1990, Poppers disappeared from store shelves. We are concerned that this potentially harmful toy is making a comeback in 1998 (Smilemakers Inc, Spartanburg, SC; June-July 1998 catalog, p. 57). In 1990, packaged poppers cautioned against applying to face or skin; we are not sure that such warnings accompany current Poppers.

Barotrauma↗
PubMed1999

Iris color alone does not predict susceptibility to the oculocardiac reflex in strabismus surgery.

PURPOSE: To test prior published observations that patients with brown irides were more susceptible to the oculocardiac reflex. SUBJECTS AND METHODS: 466 adults and children underwent surgery on an extraocular muscle under general anesthesia without anticholinergic blockade. The first rectus muscle isolated was given a predetermined specific force pull during electrocardiograph monitoring. Iris color was retrieved from the deliberate clinical charting. RESULTS: The occurrence of the oculocardiac reflex did not correlate with age, but did profoundly for the inferior rectus and least for the lateral rectus. Iris color did not influence the incidence of occurrence of moderate or severe oculocardiac reflex. CONCLUSION: The prediction of oculocardiac reflex propensity remains elusive.

Adolescent↗
PubMed1994

Lack of global vagal propensity in patients with oculocardiac reflex.

BACKGROUND: Profound bradycardia during ophthalmic surgery is a rare but potentially serious event. Little is known about the predictability of the oculocardiac reflex. METHODS: Four vagotonic maneuvers were performed on six patients who had profound oculocardiac reflex (3- to 10-second asystole) during eye surgery, the results of which were compared with 30 previously studied control subjects. Electrocardiographs were monitored during the following vagotonic maneuvers: diving response (apneic facial immersion), Valsalva maneuver, ocular compression, and carotid sinus massage. RESULTS: The degree of heart rate slowing as a result of diving response, Valsalva maneuver, and, notably, ocular compression did not differ when these patients were compared with the 30 previously studied control subjects. Carotid sinus massage produced significantly (P = 0.01) more bradycardia in the six patients (mean +/- standard deviation, -24% +/- 6%) than in the 30 control subjects (-12% +/- 7%). The heart rate response to pressure on the eyes did not correlate with prior intraoperative oculocardiac reflex. CONCLUSION: The discrepancy in heart rate sensitivity between surgical extraocular muscle tension and ocular compression may be due to different sensory receptors and brain stem processing for the trigeminally mediated oculocardiac reflex. Carotid sinus massage may help predict low heart rates during eye surgery.

Adult↗
PubMed1993

The effect of wrist rest, caffeine, and oral timolol on the hand steadiness of ophthalmologists.

Because hand steadiness is an important aspect of microsurgical technique, hand movement, amplified by a hand-held laser pointer, was measured in 14 ophthalmology trainees on four separate mornings when each had ingested (1) 200mg of caffeine, (2) 12.5mg of timolol (2.5mL of timolol 0.5% ophthalmic solution), (3) a combination of caffeine and the beta-adrenergic blocker, or (4) a placebo. Caffeine increased the resting pulse and hand movement. Although the beta-adrenergic blocker and the combination of caffeine and this drug decreased the resting heart rate from that of placebo, they did not significantly change hand steadiness. However, compared with caffeine alone, the beta-adrenergic blocker-caffeine combination significantly decreased hand movement and the pulse. Resting the wrist significantly steadied hand movements. Hand movement was not correlated with the level of ophthalmology training, the trainee's weight, or their daily caffeine consumption.

Administration, Oral↗
PubMed1991

Sensitivity to vasovagal maneuvers in normal children and adults.

In 15 male and 15 female healthy subjects who were 10 to 48 years of age, we studied alterations in heart rate and finger blood flow in response to the cold pressor test and four strong vasovagal maneuvers: diving response (apneic facial exposure to an ice water bag), Valsalva maneuver (forced expiration against a column of mercury to 40 to 50 mm Hg), unilateral carotid sinus massage, and oculocardiac reflex (inflation of a Honan balloon against one eye). Peripheral vasoconstriction as a consequence of the diving response paralleled the vasoconstriction from the cold pressor test, but it preceded the bradycardia that resulted from the diving response maneuver. In contrast, the rate of finger blood flow was high during the bradycardia that followed stage 4 of the Valsalva maneuver. Changes in heart rate correlated with age for the diving response, the Valsalva maneuver, and the oculocardiac reflex. Changes in heart rate and finger blood flow were not dependent on sex. The change in heart rate noted with the diving response was significantly correlated with that noted with the Valsalva maneuver and the oculocardiac reflex. Changes in finger blood flow did not correlate with changes in heart rate for any maneuver. This study provides a response profile of relative sensitivities to strong vasovagal maneuvers in normal children and adults.

Adolescent↗
PubMed1987

Clinical experience and plasma laudanosine concentrations during the infusion of atracurium in the intensive therapy unit.

Twenty patients in the intensive care unit received an infusion of atracurium to permit mechanical ventilation. The duration of infusion ranged from 38 to 219 h and the average rate of infusion during the study was 0.76 mg kg-1 h-1. In 14 patients an increase in atracurium requirement occurred within the first 72 h of the infusion. Recovery from neuromuscular blockade after a prolonged infusion was sufficiently rapid to avoid pharmacologically induced reversal. In six patients maximum plasma concentrations of laudanosine were 1.9-5 micrograms ml-1, and there was no evidence of cerebral excitation.

Adolescent↗
PubMed1987

Experience with I-131-metaiodobenzylguanidine (MIBG): a retrospective study.

We report a retrospective study of two years experience with I-131-metaiodobenzylguanidine (MIBG). I-131 MIBG was prepared locally and was found to have decreased background activity as compared with other available commercial preparations from Great Britain and the United States. Fifty-nine patients were studied with a total of 65 scans. The study included 11 members of a family with multiple endocrine adenomatosis (MEA) type II syndrome. Of 16 patients found to have abnormal scans, 12 had disease confirmed surgically. These cases consisted of nine pheochromocytomas, one paraganglioma, one neurilemmoma, and one neuroblastoma. MIBG scans for pheochromocytoma detection had an accuracy of 94.5%, a sensitivity of 100%, and a specificity of 93.5% in this study of patients with a high prior probability of the disease.

3-Iodobenzylguanidine↗