Presumed air by vitrectomy embolisation (PAVE) a potentially fatal syndrome

Perfluorocarbon liquid as a short-term tamponade for managing severe open globe injuries

PURPOSE

To explore the use of perfluorocarbon liquids (PFCLs) as a short-term tamponade in a staged vitrectomy approach for managing severe open globe injuries (OGIs).

METHODS

This retrospective, interventional case series included patients undergoing 23-gauge pars plana vitrectomy with PFCL tamponade for 7-14 days (mean 11.2 ± 3.36 days), followed by secondary vitrectomy and silicone oil exchange. Key outcome measures included retinal and choroidal reattachment rates, best-corrected visual acuity (BCVA), intraocular pressure (IOP), and postoperative complications. Statistical analyses were performed using McNemar's test and Student's t-test.

RESULTS

Five eyes from five patients (mean age 55.6 ± 10.12 years; male to female ratio 4:1) were included, with a mean follow-up of 8.4 ± 4.9 months. All patients sustained zone II and III globe ruptures secondary to blunt trauma, with baseline visual acuity ranging from light perception (LP) to no light perception (NLP). Intraoperative findings included total hyphema, funnel retinal detachment, traumatic choroidal rupture (TCR), suprachoroidal hemorrhage (SCH) and extensive intraocular hemorrhage (EIH). Following PFCL removal, SCH exhibited full or partial resolution, and the posterior retina remained attached in all cases. All eyes were salvaged, and visual acuity improved to hand motion (HM) on postoperative day 1, maintaining stability throughout follow-up (P = 0.03682). No significant IOP changes were observed postoperatively (preoperative: 9.66 ± 2.38 mmHg; postoperative: 9.48 ± 3.31 mmHg, P = 0.9063). Retinal and choroidal attachment were maintained during follow-up, with no cases of phthisis bulbi, endophthalmitis, recurrent hyphema, or ocular hypertension. One patient developed corneal degeneration three months postoperatively.

CONCLUSIONS

Short-term PFCL tamponade in a staged vitrectomy may facilitates retinal and choroidal stabilization while minimizing complications, offering a viable alternative for managing severe OGIs.

Life-threatening complications in ophthalmic surgery: a systematic review

Ophthalmic surgical procedures are widely acknowledged for their safety and efficacy. Undoubtedly, advances in ophthalmic surgery, along with the improvement of anaesthetic techniques, have contributed to the reduction in the occurrence of these events. However, although uncommon, systemic severe and life-threatening adverse events can still occur and it is imperative for an ophthalmologic surgeon to have a comprehensive understanding of them to act in terms of proactive prevention, prompt recognition, and optimal treatment, thus maximizing patients' outcomes. Among life-threatening complication following ophthalmic surgery, cardiovascular events represent the most common ones, including a range of different clinical entities: the oculocardiac reflex, potentially leading to haemodynamic instability and asystole; iatrogenic vascular air embolism, in form of venous air embolism or "pefluorocarbon syndrome", which can lead to obstruction of the pulmonary circulation, respiratory distress and cardiovascular collapse; postoperative venous thromboembolism, in the context of which the management of perioperative antiplatelet and anticoagulant therapy has a crucial role. Furthermore, among infectious complications, that are more commonly limited to the ocular tissues, necrotizing fasciitis represents a potentially lethal infection. This review aims to provide an up-to-date, evidence-based overview of potential life-threatening complications associated with ophthalmic surgery, exploring pathogenesis, risk factors, signs, symptoms, and, briefly, management strategies.

Local Resection in Choroidal Melanoma: A Review

Surgical resection is widely used to treat small tumours located in the iris and the ciliary body, due to the accessibility of these sites. By contrast, surgical removal of choroidal tumours is substantially more challenging, which is why this procedure is performed only at specialised centres. In the present article, we review the literature on surgical resection of choroidal tumours, which can be performed as endoresection (ab interno) or transscleral resection (ab externo). An important aim of this review is to describe and compare the two approaches in terms of visual outcomes, survival rates, and complications. Both approaches are indicated for the removal of large tumours (thickness > 8 mm) with small base diameters. Surgical resection of the tumour allows clinicians to obtain valuable histopathologic and cytogenetic data from the specimen and eliminates the risks associated with radiotherapy. However, both of these surgical approaches are technically challenging procedures involving the risk of severe early and late postoperative complications.

Main Principles of Vitrectomy Using Intraocular Tamponades - A Basic Course in Surgery

This article is intended to clearly present the basic principles for the use of intraocular tamponades in vitreous/retinal surgery in the event of retinal detachment and other pathologies using additional video footage. It examines the various gases, silicone oils and perfluorocarbon liquids with their indications, administration and in particular intraoperative handling including pitfalls and complications. Characteristic animations show the principles of use in surgery in a comprehensible way. The two lead authors dedicate this article to their teacher Prof. Dr. V.-P. Gabel, who in the early 1990s successfully established the first vitrectomy courses for ophthalmologists at Regensburg University Eye Clinic each year. Many colleagues who still work in retinal surgery today first started learning about this segment on these courses. The other coauthors participated under his supervision in annual vitrectomy wet labs run by the German Academy of Ophthalmology.

Fatal systemic (paradoxical) air embolism diagnosed by postmortem funduscopy

Air embolism is often unrecognized and underreported. Published case reports or case series describe only rare fundal examinations of retinal air emboli (RAE)-a distinctive sign of systemic air embolism. We report an infant, found unresponsive at home, who died in the emergency department after unsuccessful resuscitative efforts. Before the autopsy, diagnostic RAE were recognized and imaged during postmortem funduscopy. Postmortem radiography and an autopsy confirmed systemic (paradoxical) air embolism due to inflicted abdominal and thoracic blunt force injuries. While a few descriptions and illustrations of RAE occur in case reports, we found no published photographic images of RAE in infants, children, or adults. This case report describes and photographically documents classic RAE associated with fatal systemic (paradoxical) air embolism. Complementing postmortem radiography and judicious autopsy techniques, the detection of RAE can aid pathologists in diagnosing systemic air embolism.

Cardiorespiratory Events Associated With Ophthalmic Surgery: A Single-Center, Retrospective Records Review of 130 775 Patients, 1999–2015

Purpose:

The most recent study of ophthalmic surgery morbidity and mortality was published in 1995, with a patient study population from 1977 to 1988. The present study reports surgical outcomes from a single-center, retrospective analysis of patient records from 1999 to 2015.

Methods:

Three International Classification of Diseases–9-CM codes for cardiorespiratory events were searched in the discharge diagnoses in an eye hospital over a 16-year period. The overall mortality and preoperative risk factors were analyzed, including the type of anesthetic, type of surgery, medical comorbidities, and bradycardia preceding the cardiac events.

Results:

Between February 1, 1999 and October 1, 2015, a total of 130 775 patients presented for ophthalmic surgery. Fifty-nine patients (0.45 per 1000) experienced a cardiorespiratory event. Of the 59 patients, 14 patients had a cardiorespiratory arrest, 9 of whom died during the perioperative period. Of the remaining 45 patients, 29 had significant adverse events needing some form of advanced monitoring, evaluation, and/or intervention. There was a significantly greater prevalence of diabetes among patients who had a cardiorespiratory event ( P < .001).

Conclusions:

The major risk factor associated with ophthalmic surgery morbidity and mortality was diabetes with its associated complications of autonomic neuropathy, nephropathy, and retinopathy. Of the 9 patients who died, 8 were diabetic with proliferative diabetic retinopathy and renal insufficiency/failure. The ninth mortality was secondary to a venous air embolism during ocular air infusion. The adage that “the eye is the window to our overall health” seems to be correct.

Ocular Venous Air Embolism (OVAE): A Review

Purpose:

The purpose of this article is to review and analyze reported cases of ocular venous air embolism (OVAE) to develop a reliable clinical definition of OVAE and effective prevention strategies.

Methods:

We reviewed all reports of suspected air embolism during vitrectomy published in PubMed since the introduction of pars plana vitrectomy, and 5 cases found elsewhere and separately reported concurrent with this review.

Results:

OVAE is a precipitous drop in end-tidal CO2, a choroidal detachment, or a choroidal wound, followed by signs of impending or actual cardiovascular collapse, during vitrectomy air infusion. In each case meeting the above clinical definition, entrained air was found whenever it was sought (8/8, 100%), either by antemortem imaging or postmortem forensic investigations. Most OVAE cases were fatal (9/13, 69%), with 8 of 9 deaths (89%) occurring the day of surgery.

Conclusions:

OVEA is a rare but usually fatal complication of air infusion into the eye during vitrectomy. Although received with skepticism when first reported (2005), OVAE may be the most lethal type of surgical air embolization because of its high entrainment pressure and proximity to the heart. Because the effective response time to avoid a fatal OVAE outcome can be less than 1 minute, use of preventive measures is critical—most notably a “time out” before air infusion to confirm infusion cannula positioning, and immediate cessation of air infusion if choroidal detachment is detected.

Ocular Venous Air Embolism: A Report of 5 Cases

Purpose:

The purpose of this case series is to report 5 new cases of ocular venous air embolism (OVAE). We define OVAE as a precipitous drop in end-tidal carbon dioxide, a choroidal detachment, or a choroidal wound, followed by signs of impending or actual cardiovascular collapse, during vitrectomy air infusion.

Methods:

A case report series was retrospectively reviewed.

Results:

Four of the 5 OVAE cases (80%) were fatal, occurring in conjunction with repair of rhegmatogenous retinal detachment (2 cases); a large surgical wound of the choroid (1 case); and vitrectomy repair of an injured eye (1 case). One patient survived OVAE during choroidal melanoma endoresection after prompt discontinuance of air infusion by anesthesia personnel previously alerted to the OVAE risk.

Conclusions:

OVAE is a rare but usually fatal complication of air infusion into the eye during vitrectomy. Because the effective response time to avoid a fatal OVAE outcome can be less than 1 minute, use of preventive measures is critical.

Vascular air embolism: A silent hazard to patient safety

PURPOSE

To narratively review published information on prevention, detection, pathophysiology, and appropriate treatment of vascular air embolism (VAE).

MATERIALS AND METHODS

MEDLINE, SCOPUS, Cochrane Central Register and Google Scholar databases were searched for data published through October 2016. The Manufacturer and User Facility Device Experience (MAUDE) database was queried for "air embolism" reports (years 2011-2016).

RESULTS

VAE may be introduced through disruption in the integrity of the venous circulation that occurs during insertion, maintenance, or removal of intravenous or central venous catheters. VAE impacts pulmonary circulation, respiratory and cardiac function, systemic inflammation and coagulation, often with serious or fatal consequences. When VAE enters arterial circulation, air emboli affect cerebral blood flow and the central nervous system. New medical devices remove air from intravenous infusions. Early recognition and treatment reduce the clinical sequelae of VAE. An organized team approach to treatment including clinical simulation can facilitate preparedness for VAE. The MAUDE database included 416 injuries and 95 fatalities from VAE. Data from the American Society of Anesthesiologists Closed Claims Project showed 100% of claims for VAE resulted in a median payment of $325,000.

CONCLUSIONS

VAE is an important and underappreciated complication of surgery, anesthesia and medical procedures.

Venous Air Embolism During Pars Plana Vitrectomy: A Case Report and Review of the Literature

Purpose:

Presumed venous air embolism (PVAE) is a rare and potentially fatal complication of pars plana vitrectomy that is poorly described and understood but requires improved awareness among ophthalmologists and vitreoretinal surgeons.

Methods:

A case report is presented along with a systematic review of published reports of PVAE during ocular surgery.

Results:

An otherwise healthy adult male undergoing retinal detachment repair under local anesthesia with monitored anesthesia care died from a PVAE. Literature search yielded 2 experimental models, 6 individual case reports, and several editorials. Review of existing reports reveals that PVAE can affect patients of any age or gender with no medical predilection and occurs in cases of trauma, endoresection, or retinal detachment repair. It is typically associated with a drop in end-tidal carbon dioxide during fluid–air exchange and can present similar to a hemorrhagic choroidal detachment. Analysis suggests that venous air embolism can be prevented by ensuring full engagement of the infusion cannula into the vitreous cavity prior to fluid–air exchange.

Conclusion:

Presumed venous air embolism is a potentially fatal complication of ocular surgery and in some cases may be recognized by ophthalmologists as a choroidal detachment during fluid–air exchange in pars plana vitrectomy. It is imperative to immediately stop the air infusion line if venous air embolism is suspected.

In Vivo Porcine Model of Venous Air Embolism During Pars Plana Vitrectomy

PURPOSE

Venous air embolism (VAE) during pars plana vitrectomy (PPV) can occur owing to improper positioning of the infusion cannula in the suprachoroidal space and may lead to sudden compromise of cardiac circulation and death. This was an in vivo demonstration of fatal VAE during PPV to show that air can travel from the suprachoroidal space into the central circulation.

DESIGN

Experimental in vivo surgical study on porcine eyes.

METHODS

Experimental PPV under general anesthesia was performed on porcine eyes (Yorkshire species) at a University Surgical Training & Education Center. Infusion cannulas were placed into the suprachoroidal space and fluid-air exchange (FAE) was started with sequential increases in infusion air pressure. Vital signs of porcine animals were continuously monitored and recorded in real time during the PPV, including end-tidal carbon dioxide (ETCO₂), oxygen saturation (SaO₂), intra-arterial blood pressure, electrocardiography (EKG), and transesophageal echocardiography (TEE).

RESULTS

Intracardiac air was detected on TEE less than 30 seconds after increasing air infusion pressure to 60 mm Hg. ETCO₂ declined precipitously, followed by hypotension and EKG changes. Oxygen desaturation was a late phenomenon. The animal died within 7 minutes of VAE. During autopsy, the heart was open under water and air escaped from the right ventricle.

CONCLUSION

This in vivo porcine model confirms that during the FAE in PPV, pressurized air from an infusion cannula malpositioned in the suprachoroidal space can transit through the eye to the central circulation, resulting in fatal VAE.

Tamponade in the surgical management of retinal detachment

Despite treatment advances, rhegmatogenous retinal detachment (RD) can have poor visual outcomes even with prompt and appropriate therapy. Pars plana vitrectomy is a leading management modality for the treatment of RD. This procedure is generally accompanied by the use of internal tamponade. Various gases and silicone oils may yield beneficial outcomes. Heavy silicone oils have been approved in some European nations but are not available in the USA. Different tamponade agents have unique benefits and risks, and choice of the agent should be individualized according to the characteristics of the patient and RD, as well as perioperative and postoperative factors.

Ophthalmic regional blocks: management, challenges, and solutions

In the past decade ophthalmic anesthesia has witnessed a major transformation. The sun has set on the landscape of ophthalmic procedures performed under general anesthesia at in-hospital settings. In its place a new dawn has ushered in the panorama of eye surgeries conducted under regional and topical anesthesia at specialty eye care centers. The impact of the burgeoning geriatric population is that an increasing number of elderly patients will present for eye surgery. In order to accommodate increased patient volumes and simultaneously satisfy administrative initiatives directed at economic frugality, administrators will seek assistance from anesthesia providers in adopting measures that enhance operating room efficiency. The performance of eye blocks in a holding suite meets many of these objectives. Unfortunately, most practicing anesthesiologists resist performing ophthalmic regional blocks because they lack formal training. In future, anesthesiologists will need to block eyes and manage common medical conditions because economic pressures will eliminate routine preoperative testing. This review addresses a variety of topical issues in ophthalmic anesthesia with special emphasis on cannula and needle-based blocks and the new-generation antithrombotic agents. In a constantly evolving arena, the sub-Tenon's block has gained popularity while the deep angulated intraconal (retrobulbar) block has been largely superseded by the shallower extraconal (peribulbar) approach. Improvements in surgical technique have also impacted anesthetic practice. For example, phacoemulsification techniques facilitate the conduct of cataract surgery under topical anesthesia, and suture-free vitrectomy ports may cause venous air embolism during air/fluid exchange. Hyaluronidase is a useful adjuvant because it promotes local anesthetic diffusion and hastens block onset time but it is allergenic. Ultrasound-guided eye blocks afford real-time visualization of needle position and local anesthetic spread. An advantage of sonic guidance is that it may eliminate the hazard of globe perforation by identifying abnormal anatomy, such as staphyloma.

Percutaneous cardiopulmonary support to treat suspected venous air embolism with cardiac arrest during open eye surgery: a case report

We report a case of possible venous air embolism (VAE) during trans pars plana vitrectomy with air-fluid exchange of the vitreous cavity. Shortly after initiation of air-fluid exchange, decreases in end-tidal CO2, oxygen saturation, and blood pressure were observed. The patient rapidly progressed to cardiac arrest unresponsive to cardiopulmonary resuscitation, and recovered after the application of percutaneous cardiopulmonary support. Prompt termination of air infusion is needed when VAE is suspected during air-fluid exchange, and extracorporeal life support should be considered in fatal cases. Although the incidence is rare the possibility of VAE during ophthalmic surgery clearly exists, and therefore awareness and vigilant monitoring seem critical.