Perioperative Visual Loss in Cardiac Surgery

[Perioperative visual loss : Rare, unknown, relevant?]

Perioperative visual loss (POVL) is a rare but severe complication following non-ophthalmological surgery under general anesthesia. A POVL can be caused by lesions in any part of the optical system. The predominant causes include corneal injuries and particularly ischemic damage. The symptoms of POVL substantially vary ranging from reduced vision to complete blindness. The risks involve factors related to the surgery as well as patient-specific factors. In general, the prognosis in cases of mechanical damage is better than for ischemic lesions. The treatment measures depend on the underlying pathomechanism and due to the limited evidence only a few treatment options are available. Therefore, preventive measures and meticulous documentation play a crucial role.

Incidence and Risk Factors for Postoperative Visual Loss after Cardiac Surgical Procedures: A Systematic Review

ABSTRACT

Postoperative visual loss (POVL) is an infrequent yet consequential complication that can follow cardiac surgical interventions. This systematic review aims to provide a comprehensive analysis of the incidence of POVL after cardiac surgery and to delineate the associated risk factors. A comprehensive search was conducted in major medical databases for relevant studies published up to September 2022. Eligible studies reporting on the incidence of POVL and identifying risk factors in patients undergoing cardiac surgery were included. Data extraction was performed independently by two reviewers. The pooled incidence rates and the identified risk factors were synthesized qualitatively. POVL after cardiac surgery has an overall incidence of 0.015%, that is, 15 cases per 100,000 cardiac surgical procedures. Risk factors for POVL include patient characteristics (advanced age, diabetes, hypertension, and preexisting ocular conditions), procedural factors (prolonged surgery duration, cardiopulmonary bypass time, and aortic cross-clamping), anesthetic considerations (hypotension, blood pressure fluctuations, and specific techniques), and postoperative complications (stroke, hypotension, and systemic hypoperfusion). Ischemic optic neuropathy (ION) is an uncommon complication, associated with factors like prolonged cardiopulmonary bypass, low hematocrit levels, excessive body weight gain, specific medications, hypothermia, anemia, raised intraocular pressure, and micro-embolization. Diabetic patients with severe postoperative anemia are at increased risk for anterior ischemic optic neuropathy (AION). Posterior ischemic optic neuropathy (PION) can occur with factors like hypertension, postoperative edema, prolonged mechanical ventilation, micro-embolization, inflammation, hemodilution, and hypothermia.While the overall incidence of POVL postcardiac surgery remains modest, its potential impact is substantial, necessitating meticulous consideration of modifiable risk factors. Notably, prolonged surgical duration, intraoperative hypotension, anemia, and reduced hematocrit levels remain salient contributors. Vigilance is indispensable to promptly detect this infrequent yet visually debilitating phenomenon in the context of postcardiac surgical care.

Perioperative Blindness in Spine Surgery: A Scoping Literature Review

Perioperative vision loss (POVL) is a devastating surgical complication that impacts both the recovery from surgery and quality of life, most commonly occurring after spine surgery. With rates of spine surgery dramatically increasing, the prevalence of POVL will increase proportionately. This scoping review aims to aggregate the literature pertinent to POVL in spine surgery and consolidate recommendations and preventative measures to reduce the risk of POVL. There are several causes of POVL, and the main contribution following spine surgery is ischemic optic neuropathy (ION). Vision loss often manifests immediately following surgery and is irreversible and severe. Diffusion weighted imaging has recently surfaced as a diagnostic tool to identify ION. There are no effective treatments; therefore, risk stratification for counseling and prevention are vital. Patients undergoing prone surgery of long duration and/or with significant expected blood loss are at greatest risk. Future research is necessary to develop effective treatments.

Decoding the Neurological Sequelae of General Anesthesia: A Review

General anesthesia is an integral part of modern surgical practice, but it is associated with a number of complications, including neurological ones. This article provides a thorough analysis of these complications, taking into account the most common ones like drug complications, through delirium, postoperative cognitive impairment (POCD), to the rarest ones like perioperative stroke (POS), spinal cord ischemia (SCI), and postoperative visual loss (POVL). Its main goal is to familiarize healthcare professionals, especially those involved in anesthesiology, with the intricacies of neurological complications. Given their specificity and frequency of occurrence, it is well known that the diagnosis and management of these complications can sometimes cause problems for physicians without advanced neurological knowledge. Also, in addition to complex diagnostics, the pathomechanism of non-pharmacological complications is often not fully understood due to their multifactoriality and sometimes paucity of research. For this reason, an increasing amount of work is being done in the medical community to better understand this group of conditions, enabling faster diagnosis and more effective treatment, as well as perioperative prevention. This paper aims to increase awareness and vigilance among physicians across the spectrum of surgical patient care, from premedication to postoperative follow-up. Drawing on the authors' experience and the extensive medical literature, this paper includes 39 selected articles from 1994 to 2023, seeking the latest insights in the constantly evolving field of neurology and anesthesiology. This article aims to review the neurological complications of general anesthesia.

Risk Factors for Stroke Development After Thoracic Aortic Surgery

OBJECTIVES

Stroke after thoracic aortic surgery is a complication that is associated with poor outcomes. The aim is to characterize the intraoperative risk factors for stroke development.

DESIGN

A retrospective analysis.

SETTING

Tertiary, high-volume cardiac surgery center.

PARTICIPANTS

Patients who had surgical repair of thoracic aortic diseases from January 1, 2017, through December 31, 2021.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A total of 704 patients were included, of whom 533 had ascending aortic aneurysms, and 171 had type A aortic dissection. The incidence of postoperative stroke was 4.5% (95% CI 2.9%-6.6%) for ascending aortic aneurysms compared with 12.3% (95% CI 7.8%-18.16%) in type-A aortic dissections. Patients who developed postoperative strokes had significantly lower intraoperative hemoglobin median (7.5 gm/dL [IQR 6.8-8.6] v 8.55 gm/dL [IQR 7.3-10.0]; p < 0.001). The median cardiopulmonary bypass time was 185 minutes (IQR 136-328) in the stroke group versus 156 minutes (IQR 113-206) in the nonstroke group (p = 0.014). Circulatory arrest was used in 57.8% versus 38.5% of the nonstroke patients (p = 0.017). The initial temperature after leaving the operating room was lower, with a median of 35.0°C (IQR 34-35.92) in the stroke group versus 35.5°C (IQR 35-36) in the nonstroke cohort (p = 0.021).

CONCLUSIONS

This single-center study highlighted the potential importance of intra-operative factors in preventing stroke. Lower hemoglobin, longer duration of cardiopulmonary bypass, deep hypothermic circulatory arrest, and postoperative hypothermia are potential risk factors for postoperative stroke. Further studies are needed to prevent this significant complication in patients with thoracic aortic diseases.

Impact of coronary artery bypass grafting surgery on the chorioretinal biomicroscopic characteristics

BACKGROUND

Most patients with cardiovascular disorders suffer from coronary artery diseases, which can be treated successfully using coronary artery bypass grafting (CABG). One of the unpleasant events following CABG is postoperative vision loss (POVL). Vulnerability of retinal vessels to hemodynamic changes, an expectable event following CABG, may contribute to the development of POVL, which might be associated with the changes in the choroidal and retinal structures.

AIM

To investigate postoperative changes in chorioretinal and peripapillary nerve fiber layer (NFL) thickness, and progression of diabetic and hypertensive retinopathy after CABG.

METHODS

In this prospective, cross-sectional study, 49 eyes in 25 candidates for CABG underwent both ophthalmic and cardiovascular examinations within 6 mo prior to and 9 mo after surgery.

RESULTS

Among the study participants, 56% were male with a mean age of 62.84 years ± 10.49 years (range 33-80 years). Diabetes mellitus was observed in eight participants (32%). None of the patients suffered from postoperative anterior or posterior ischemic optic neuropathy, central retinal artery occlusion, and cortical blindness. The mean value of the preoperative best corrected visual acuity was 0.11 ± 0.10 logMAR (range, 0-0.4), which worsened to 0.15 ± 0.08 logMAR (range, 0-0.4) after CABG (P = 0.031). No significant difference was observed between the pre- and postsurgical choroidal (P = 0.853) and macular (P = 0.507) thickness, NFL thickness in the subfoveal (P > 0.999) and peripapillary areas (P = 0.659), as well as the severity of diabetic and hypertensive retinopathy.

CONCLUSION

CABG may reduce visual acuity without affecting ocular structures. Postoperative vision reduction might be attributable to molecular or cellular variations, changes in visual pathway function, or central nervous system.

The effect of off-pump coronary bypass graft surgery on subfoveal choroidal thickness, ganglion cell complex, and retinal nerve fiber layer thickness

Background

Cardiac surgery has been associated with adverse ocular events. Off-pump coronary artery bypass graft surgery evades the systemic inflammatory response seen in extracorporeal circulation and is superior to on-pump surgery with regard to end-organ dysfunction and neurological outcomes.

Objectives

To determine the effects of off-pump (without extracorporeal circulation) coronary artery bypass graft surgery on choroidal thickness, ganglion cell complex, and the retinal nerve fiber layer.

Design

Prospective, longitudinal study.

Methods

Patients who underwent off-pump surgery were examined preoperatively and postoperatively at 1 week and 6 weeks after surgery. Choroidal thickness, ganglion cell complex, and the retinal nerve fiber layer measurements were recorded, and the effects of off-pump coronary artery bypass on these parameters were assessed.

Results

A total of 44 eyes of 44 patients were included in the study. There was a statistically significant increase in subfoveal choroidal thickness from 252.84 ± 56.24 µm preoperatively to 273.82 ± 39.76 µm at 1 week and 301.97 ± 44.83 µm at 6 weeks after off-pump coronary artery bypass graft surgery (p = 0.044; p ⩽ 0.001). Ganglion cell complex and retinal nerve fiber measurements showed no significant difference compared to preoperative values.

Conclusion

Off-pump coronary artery bypass graft surgery showed no negative effects on ganglion cell complex and retinal nerve fiber measurements. A significant increase in subfoveal choroidal thickness was seen after off-pump surgery, which might be advantageous in patients who are at high risk or have preexisting ocular diseases that are affected by the choroid.

Perioperative Care of the Patient with Eye Pathologies Undergoing Nonocular Surgery

The authors reviewed perioperative ocular complications and implications of ocular diseases during nonocular surgeries. Exposure keratopathy, the most common perioperative eye injury, is preventable. Ischemic optic neuropathy, the leading cause of perioperative blindness, has well-defined risk factors. The incidence of ischemic optic neuropathy after spine fusion, but not cardiac surgery, has been decreasing. Central retinal artery occlusion during spine fusion surgery can be prevented by protecting eyes from compression. Perioperative acute angle closure glaucoma is a vision-threatening emergency that can be successfully treated by rapid reduction of elevated intraocular pressure. Differential diagnoses of visual dysfunction in the perioperative period and treatments are detailed. Although glaucoma is increasingly prevalent and often questions arise concerning perioperative anesthetic management, evidence-based recommendations to guide safe anesthesia care in patients with glaucoma are currently lacking. Patients with low vision present challenges to the anesthesia provider that are becoming more common as the population ages.

Factors Affecting Optic Nerve Damage in Le Fort III Osteotomy: A Retrospective Study

The causes of visual impairment following Le Fort osteotomy for syndromic craniosynostosis have not been completely elucidated. The authors investigated the potential causes and means of prevention of optic nerve damage, with particular emphasis on intraoperative blood transfusion volume and operating time. This retrospective study evaluated patients who underwent Le Fort III osteotomy for syndromic craniosynostosis between 2000 and 2020. Data on pupillary reflex, pupil size, operating time, blood transfusion, age at time of surgery, sex, and syndrome type were obtained from medical records. Univariate analysis and multivariate analysis with the level of statistical significance set at P<0.05. For the 86 patients included, the mean values of operating time, amount of blood transfusion based on body weight, amount of blood transfusion per body weight per hour, and age were 6.0 hours (range: 3.5-12.3 h), 30.5 mL/kg (range: 0-322 mL/kg), 5.14 mL/kg/h (range: 0-35.7 mL/kg/h), and 10.0 years (range: 4-38 y), respectively. Crouzon, Apert, and Pfeiffer syndromes were observed in 49, 29, and 8 patients, respectively. Abnormal pupillary findings were observed in 27 patients of whom 25 showed no abnormalities in subsequent visual function and 2 developed blindness. Abnormal pupillary findings correlated with the amount of blood transfused per body weight (P=0.0082) and amount of blood transfused per body weight per hour (P=0.0052). As demonstrated in this study, increased intraoperative bleeding and amount of blood transfused were associated with optic nerve damage, particularly during acute bleeding. Prompt inspection of the pupils following surgery is therefore warranted.

Neurologic complications of heart surgery

Cardiac surgeries are commonly associated with neurologic complications. The type and complexity of the surgery, as well as patients' comorbidities, determine the risk for these complications. Awareness and swift recognition of these complications may have significant implications on management and prognosis. Recent trials resulted in an expansion of the time window to treat patients with acute ischemic stroke with intravenous thrombolysis and/or mechanical thrombectomy using advanced neuroimaging for screening. The expanded time window increases the reperfusion treatment options for patients that suffer a periprocedural ischemic stroke. Moreover, there is now limited data available to help guide management of intracerebral hemorrhage in patients undergoing treatment with anticoagulation for highly thrombogenic conditions, such as left ventricular assist devices and mechanical valves. In addition to cerebrovascular complications patients undergoing heart surgery are at increased risk for seizures, contrast toxicity, cognitive changes, psychological complications, and peripheral nerve injuries. We review the neurological complications associated with the most common cardiac surgeries and discuss clinical presentation, diagnosis and management strategies.

Ocular Complications in the Prone Position in the Critical Care Setting: The COVID-19 Pandemic

PURPOSE

Ocular complications are common in the critical care setting but are frequently missed due to the focus on life-saving organ support. The SARS-CoV-2 (COVID-19) pandemic has led to a surge in critical care capacity and prone positioning practices which may increase the risk of ocular complications. This article aims to review all ocular complications associated with prone positioning, with a focus on challenges posed by COVID-19.

MATERIALS AND METHODS

A literature review using keywords of "intensive care", "critical care", "eye care", "ocular disorders", "ophthalmic complications," "coronavirus", "COVID-19," "prone" and "proning" was performed using the electronic databases of PUBMED, EMBASE and CINAHL.

RESULTS

The effects of prone positioning on improving respiratory outcomes in critically unwell patients are well established; however, there is a lack of literature regarding the effects of prone positioning on ocular complications in the critical care setting. Sight-threatening ophthalmic disorders potentiated by proning include ocular surface disease, acute angle closure, ischemic optic neuropathy, orbital compartment syndrome and vascular occlusions.

CONCLUSIONS

COVID-19 patients may be more susceptible to ocular complications with increased proning practices and increasing demand on critical care staff. This review outlines these ocular complications with a focus on preventative and treatment measures to avoid devastating visual outcomes for the patient.

Incidence of Ischemic Optic Neuropathy After Cardiopulmonary Bypass: 20-Year Experience

OBJECTIVE

This study evaluated the incidence and risk factors for ischemic optic neuropathy (ION) as a complication of cardiac surgery requiring cardiopulmonary bypass (CPB).

DESIGN

Retrospective chart review of prospectively collected data at a tertiary care center.

SETTING

Single tertiary academic referral center.

PARTICIPANTS

This study comprised 44,568 cardiac surgery patients who underwent CPB between January 1, 1995, and January 5, 2017, using the Society of Thoracic Surgeons database and cross-matching it with International Classification of Diseases codes for visual changes.

INTERVENTIONS

None; this was a retrospective chart review.

MEASUREMENTS AND MAIN RESULTS

Six patients initially were identified as experiencing visual changes. Only 1 patient from 44,568 cardiac surgeries with CPB between January 1, 1995, and January 5, 2017, experienced ION, for an incidence 0.22 per 10,000. Because only 1 patient experienced ION, the authors were unable to determine risk factors for this complication; however, the nadir perioperative hemoglobin in the affected patient was 7.3 g/dL (postoperative).

CONCLUSION

The incidence of ION decreased from 6 per 10,000 in the authors' previous study from 1976-1994 to 0.22 per 10,000 in the present study. Because of the low incidence of this dreaded complication, the authors were not able to identify risk factors for ION. Practice improvements (eg, transition to membrane oxygenators, blood transfusion guidelines, less- invasive surgical options for high-risk patients) during the time between the authors' studies likely affected the incidence reduction.

INFLUENCE OF THE ACUTE INFLAMMATION AND ENDOTHELIAL DYSFUNCTION ON THE RETINAL VEIN OCCLUSION FORMATION AFTER CARDIO-SURGICAL INTERFERENCES WITH THE USE OF CARDIOPULMONARY BYPASS

Acute inflammation and endothelial dysfunction (EDF) are typical pathological processes, which determine the development of retinal vein occlusion (RVO) during cardio-surgery with the use of cardiopulmonary bypass (CB), but the connection of seromarkers according to the terms of occlusion appearance remains undefined. The aim – to determine the influence of the acute inflammation and EDF for RVO formation after cardio-surgical interferences with the use of CB according to the terms of occlusion appearance. Material and methods. There were selected for the research the data of 137 eyes (126 patients, the main group) with RVO after the surgery with CB. The comparison group contains the data about examination of 86 eyes (43 patients), who had not any occlusion during all term of examination. The control group consisted of 10 eyes (5 patients) without occlusion, which were examined before surgery. An ophthalmologist 2, 7, 30, 60, 90 and 180 days after cardio-surgical interference, examined patients. The content of IL-6, IL-8 and VE-cadherin in blood serum was determined by immunoenzyme technique (Bender Medsystems, Austria). Statistical data processing was performed with the use of Statistica 10 program (StatSoft, Inc., USA), regression analysis – with the use of the program package GLZ. Results. The conduction of cardio-surgeries with the use of CB caused an increase of the interleukins content in the early period (IL-6 on the 2nd and 7th days, and IL-8 up to 30 days), while the content of VE-cadherin (VE-C) was slightly increased during almost all period of monitoring. With the availability of RVO, the content of IL-6 during all terms of occlusion appearance was significantly higher, the content of IL-6 was up to 30 days, and the content of VE-C in a greater degree was after the 7th day. The regression analysis showed that after 1-2 days RVO appearance was directly related with the content of IL-6 and IL-8 in the blood, on the 3rd and 7th days – only with the content of IL-8, on the 8th and 30th days – with the content of all markers, and then with the content of IL-6 and VE-C. The accuracy of the prediction of the presence or absence of RVO at the appropriate period according to the calculated regression model is at least 78 % (p <0.001), what proves the influence of markers on the development of RVO. Conclusions. The undertaken study shows the meaning of the acute inflammation and EDF by appearance of RVO with the use of CB, what justifies the application of the preventive measures - at the early stages the restriction of activity of the inflammatory process, at the later stages – prevention of EDF development.