Jasmin Retzlaff

A formula for predicting aphakic refraction from axial length and keratometry measurements was derived from 120 cases, using linear regression analysis, as follows: Psp = 80.4 - 1.65L -0.7K, where P indicates aphakic spectacle power in diopters; L, axial length in millimeters; and K, result of keratometry in diopters. The prediction accuracy of this simple formula was compared with that of a complex theoretic formula based on geometric optics in 205 additional cases. The prediction accuracy of the theoretic and linear regression-derived formulas was virtually identical despite their differences in complexity and derivation. The differences and similarities between theoretic-derived and regression-derived aphakic and pseudophakic prediction formulas are discussed.

There are many good methods of removing lens cortex during extracapsular cataract extraction in use today. Features of some of these are presented. Flow volume of irrigation solution and depth of the anterior chamber are discussed, and it is recommended that adequate flow volume be used to maintain a comfortably deep anterior chamber during irrigation and aspiration.

BACKGROUND AND AIMS: Effective intraprocedural anticoagulation is essential during catheter ablation of atrial fibrillation (AF) and left atrial tachycardia (AT) procedures. This study evaluated a novel, standardized, nurse-led heparin protocol regarding anticoagulation performance and safety. METHODS: Consecutive patients undergoing AF or AT ablation between May 2022 and 2023 were treated using a standardized heparinization protocol managed by electrophysiology nursing staff (study group) and compared with consecutive patients undergoing ablation between May 2021 and April 2022, in whom heparin was administered at the operator's discretion (control group). Patients in the study cohort received an initial dose of 5000 IU heparin after venous access and a supplemental bolus (1000 IU/10 kg above 50 kg bodyweight) after transseptal puncture. ACT was then assessed every 20 min using a point-of-care coagulation device in both groups. Repeat heparin administration was autonomously performed by nurses in the study group following a standardized protocol. The primary endpoint was the proportion of patients in whom at least one intraprocedural ACT measurement exceeded 300 s at any time during the procedure. RESULTS: Each group included 655 patients with comparable baseline characteristics. The study group more frequently achieved the therapeutic target (ACT > 300 s, 84.6% vs. 59.7%, p < 0.0001), reached therapeutic ACT faster, and showed fewer exclusively subtherapeutic ACT values. Excessive anticoagulation was less common (ACT > 400 s: 2.0% in the study group vs. 5.0% in the control group, p = 0.0027). Complication rates were low and similar in both groups. CONCLUSIONS: A standardized, nurse-led heparinization protocol improved the speed, consistency, and precision of intraprocedural anticoagulation during left atrial ablation without increasing procedural complications.

Abstract Background Current guidelines recommend intraprocedural administration of unfractionated heparin targeting an activated clotting time (ACT) &amp;gt;300 s for left atrial ablation procedures. Aims To evaluate a novel standardized heparinization protocol in a prospective patient cohort undergoing left atrial ablation procedures in terms of effectivity of intraprocedural anticoagulation and patient safety. Methods Consecutive patients undergoing left atrial ablation for AF or left atrial tachycardia (LAT) between 05/2022 and 05/2023 were prospectively enrolled. A novel standardized heparinization protocol was implemented in the study group. Patients who underwent AF or LAT ablation between 05/2021 and 04/2022 without the use of a standardized heparin protocol served as a control group. Patients in both groups received initially 5000 I.U. of heparin after groin puncture. After transseptal puncture, patients in the study group received for each ten kilograms above a bodyweight of 50 kilograms further 1000 I.U. of heparin. ACT measurements were then conducted every 20 minutes. In cases of ACT values &amp;lt;300s further heparin was administered following the standardized protocol based on body weight and ACT in the study group autonomously by nurses. Patients in the control group received further heparin based on operator’s discretion. The primary endpoint was defined as at least one documented ACT &amp;gt;300s. Results A total of 655 patients (218 females, 33.2%) with a mean age of 65.2±11.0 years and a mean BMI of 28.7±5.5 kg/m2 were included into the study group. Median CHA2DS2-VASC score was 2 {1;3} and median HAS-BLED score 1 {1;2}. The control group consisted of 655 patients and there were no statistically significant differences with regards to baseline characteristics among patient cohorts (table 1). Radiofrequency-based PVI or left atrial ablation was performed in 313 (52.7%) patients, cryoballoon PVI in 154 (25.9%) patients and pulsed field ablation in 128 (21.5%) patients. Detailed procedural data is shown in table 2 for both groups. The primary endpoint occurred significantly more often in the study group (554 patients (84.6%) vs. 391 patients (59.6, p&amp;lt;0.0001). Periprocedural complications occurred in 12 patients of the study group (1.8%): 3 AV fistulas (0.5%), 3 pseudoaneurysms (0.5%), three pericardial tamponades (0.5%) and 3 periprocedural transitoric ischemic attack or strokes (0.5%). Notably, the three patients who experienced TIA/stroke had an effective ACT&amp;gt;300s at the end of the procedure. Complication rates in the control group were similar with no significantly difference in occurrence of transitoric ischemic attacks or strokes. Conclusions Implementing a heparinization protocol led to a significantly higher rate of patients reaching at least one intraprocedural ACT &amp;gt;300s during left atrial ablation procedures. Furthermore, a protocol that nurses can follow independently may simplify intraprocedural ACT management for the operator.