Venous air embolism from central venous catheterization: a need for increased physician awareness

Sudden cardiovascular collapse during the TUL procedure: A case series

Although ureteroscopy is a minimally invasive procedure, there have been reports of some minor and major complications, from self-limited to complicated events such as ureteral avulsion, urosepsis, and even death due to cerebrovascular accidents and deep vein thrombosis. Herein, we aim to report seven patients who presented with cardiovascular collapse during ureteroscopy in a 19-year period from January 2002 to January 2021.

Precise Terminology and Specified Catheter Insertion Length in Ultrasound-Guided Infraclavicular Central Vein Catheterization

Background and Objectives: As the latest research encourages the ultrasound-guided infraclavicular central venous approach, due to the lateral puncture site displacement, in comparison to the anatomical landmark technique based on subclavian vein catheterization, the need to re-calculate the optimal catheter insertion length and possibly to rename the punctuated vessel emerges. Although naming a particular anatomical structure is a nomenclature issue, a suboptimal catheter position can be associated with multiple life-threatening complications and must be avoided. The main study objective is to determine the optimal catheter insertion length by the most proximal ultrasound-guided, in-plane infraclavicular central vein approach, to compare results with the anatomical landmark technique based on subclavian vein catheterization and to clarify the punctuated anatomical structure. Materials and Methods: 109 patients were enrolled in this study. All procedures were performed according to the same catheterization protocol. In order to determine optimal insertion length, chest X-ray scans with an existing catheter were performed. The definition of punctuated vessel was based on computer tomography and evaluated by radiologists. Independent predictors for optimal insertion length were identified, prediction equations were generated. Results: The optimal catheter insertion length is approximately 1.5 cm longer than estimated by Pere's formula and can be accurately calculated based on anthropometric data. Computed tomography revealed: five cases with subclavian vein puncture and three cases with axillary vein puncture. Conclusions: Even the most proximal ultrasound-guided infraclavicular central vein access does not guarantee subclavian vein catheterization. A more accurate term could be infraclavicular central venous access, with the implication that the entry point could be through either subclavian or axillary veins. The optimal insertion length is approximately 1.5 cm deeper than the length determined for the anatomical landmark technique based on subclavian vein catheterization.

Central venous pressure line insertion for the primary health care physician

Central venous access is an important procedure to understand and perform not only in the emergency unit but also for prolonged reliable venous access. All clinicians must be familiar and confident with this procedure. This paper will focus on applied anatomy in respect of common anatomical sites for venous access, the indications, the contraindications, the technique and complications that may arise following the procedure. This article is part of a series on vascular access. We have previously written on the intra osseous procedure and an article on umbilical vein catheterisation will follow.

A High-pressure Solution for a High-pressure Situation: Management of Cerebral Air Embolism with Hyperbaric Oxygen Therapy

Cerebral air embolism can complicate many medical procedures, including cardiac surgery, venous and arterial access, and laparoscopic surgery. It can be a devastating diagnosis and can cause a life-threatening compromise to the cardiac, respiratory, or cerebrovascular system. It is a rare complication of central venous vascular access manipulation. A cerebral air embolism can lead to acute ischemic and cerebral oedema, which mimics other stroke syndromes, but the acute treatment differs, with prompt administration of hyperbaric oxygen therapy being the mainstay of treatment. A 59-year-old male became acutely unresponsive followed by the emergence of evolving neurology with fixed gaze palsy and a dense 0/5 left-sided hemiparesis. This occurred shortly after a right internal jugular central venous catheter (CVC) was removed (against protocol) during inspiration and sitting upright. Computed tomography (CT) imaging showed air in the right internal jugular vein, as well as intraparenchymal air. Treatment with hyperbaric oxygen was instituted within six hours. There was an excellent recovery of neurologic function, with power improving to 4+/5 over the course of the following week. Clinical staff need to be aware of the policy for central line removal, as well as having a high index of suspicion for air embolism in patients with evolving neurology immediately post-line removal. Early consideration of hyperbaric oxygen can result in improved functional outcomes.

PICC insertion in the sitting position for a patient with congestive heart failure: A case report

RATIONALE

A peripherally inserted central catheter (PICC) is typically inserted with the patient in the supine position. Here, we placed a PICC in a patient in the sitting position, in order to treat congestive heart failure.

PATIENT CONCERNS

A 65-year-old man was diagnosed with end-stage lung cancer. He had experienced septic shock and was medicated with continuous infusion of noradrenaline through a peripheral vein, in order to maintain sufficient blood pressure. However, indwelling peripheral venous catheters were difficult to place and maintain.

DIAGNOSIS

The patient experienced orthopnea due to congestive heart failure and could not assume any other position.

INTERVENTIONS

An anesthesiologist performed PICC placement while the patient was in the sitting position, using ultrasound guidance.

OUTCOMES

The patient's orthopnea was slightly ameliorated, and he was able to sleep at night.

LESSONS

The technique of inserting a PICC in the sitting position is simple and feasible. This approach may be useful for patients in whom central venous access is needed, but the supine position cannot be achieved.

Massive air embolism while removing a central venous catheter

Air embolism is a rare but mostly iatrogenic complication of medical or surgical procedures and may have a serious outcome. On the removal of a central venous catheter (CVC), minor carelessness can lead to a venous air embolism sometimes accompanied by arterial embolism. We experienced the case of a 61-year-old male who suffered from a paradoxical systemic air embolism while we removed a CVC. Immediate resuscitation and venovenous extracorporeal membrane oxygenation support saved his life. Multiple end-organ damage related to the systemic air embolism was noted, including the kidney, liver, and brain. In echocardiography, multiple air bubbles and an atrial septal defect were observed. An air embolism is preventable with appropriate precautions and techniques. Therefore, it is important to identify errors and prevent occurrence.

Cortical Blindness and Altered Mental Status following Routine Hemodialysis, a Case of Iatrogenic Cerebral Air Embolism

Cerebral air embolism is a known complication from a myriad of iatrogenic causes. This case describes a 60-year-old female presenting from hemodialysis with altered mental status, bilateral homonymous hemianopia, and repetitive speech. A noncontrast head CT revealed air in the vein of Galen and the deep cerebral veins of the left thalamus and occipital sulcus, a complication from air being introduced into the patient via improper flushing of dialysis tubing. The retrograde flow of air bubbles in the upright patient during dialysis was likely responsible for the air embolus lodging in the cerebral vasculature. This patient was transferred to receive hyperbaric therapy, whereupon the patient survived with residual attention and spatial deficits.

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 related to the use of central catheters revisited: with emphasis on dialysis catheters

Venous air embolism is a dreaded condition particularly relevant to the field of nephrology. In the face of a favourable, air-to-blood pressure gradient and an abnormal communication between the atmosphere and the veins, air entrance into the circulation is common and can bring about venous air embolism. These air emboli can migrate to different areas through three major routes: pulmonary circulation, paradoxical embolism and retrograde ascension to the cerebral venous system. The frequent undesirable outcome of this disease entity, despite timely and aggressive treatment, signifies the importance of understanding the underlying pathophysiological mechanism and of the implementation of various preventive measures. The not-that-uncommon occurrence of venous air embolism, often precipitated by improper patient positioning during cervical catheter procedures, suggests that awareness of this procedure-related complication among health care workers is not universal. This review aims to update the pathophysiology of venous air embolism and to emphasize the importance of observing the necessary precautionary measures during central catheter use in hopes of eliminating this unfortunate but easily avoidable mishap in nephrology practice.

Comparison of the Trendelenburg position versus upper-limb tourniquet on internal jugular vein diameter

BACKGROUND

Central venous cannulation is a necessary invasive procedure for fluid management, haemodynamic monitoring and vasoactive drug therapy. The right internal jugular vein (RIJV) is the preferred site. Enlargement of the jugular vein area facilitates catheterization and reduces complication rates. Common methods to enlarge the RIJV cross-sectional area are the Trendelenburg position and the Valsalva maneuver.

OBJECTIVE

Compare the Trendelenburg position with upper-extremity venous return blockage using the tourniquet technique.

DESIGN

Prospective clinical study.

SETTING

University hospital.

SUBJECTS AND METHODS

Healthy adult volunteers (American Society of Anesthesiologists class I) aged 18-45 years were included in the study. The first measurement was made when the volunteers were in the supine position. The RIJV diameter and cross-sectional area were measured from the apex of the triangle formed by the clavicle and the two ends of the sternocleidomastoid muscle, which is used for the conventional approach. The second measurement was performed in a 20° Trendelenburg position. After the drainage of the veins using an Esbach bandage both arms were cuffed. The third measurement was made when tourniquets were inflated.

MAIN OUTCOME MEASURE(S)

Hemodynamic measurements and RIJV dimensions.

RESULTS

In 65 volunteers the diameter and cross-sectional area of the RIJV were significantly widened in both Trendelenburg and tourniquet measurements compared with the supine position (P < .001 for both measures). Measurements using the upper extremity tourniquet were significantly larger than Trendelenburg measurements (P=.002 and < .001 for cross-sectional area and diameter, respectively).

CONCLUSION

Channelling of the upper-extremity venous return to the jugular vein was significantly superior when compared with the Trendelenburg position and the supine position.

LIMITATIONS

No catheterization and study limited to healthy volunteers.

Point-Of-Care Ultrasound Diagnosis of Intravascular Air After Lower Extremity Intraosseous Access

BACKGROUND

Vascular air embolism is a rare but potentially deadly phenomenon. Early diagnosis allows providers to initiate measures aimed at preventing further air entry, preventing the migration of air to the lungs, and mitigating the hemodynamic effects of pulmonary air embolism.

CASE REPORT

An emergency physician used point-of-care ultrasound to identify intravascular air before embolization to the pulmonary vasculature. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Bedside ultrasound can be used as a tool for early diagnosis of intravascular air. Emergency physicians should be aware of the typical sonographic manifestations of intravascular air and the initial steps in treating vascular air embolism.

A unique case of venous air embolus with survival

Venous air embolus (VAE) occurs when gas, specifically atmospheric air, enters into the vascular system. Although rare, they can be fatal due to risk of cardiovascular collapse. In this report, we present a unique case of a 66-year-old female trauma patient with an inferior vena cava air embolism. An overview of the potential cause is presented, along with a review of the management of VAE.

Bubbles in the Heart: A Case of Venous Air Thromboembolism

Introduction

Venous air embolism (VAE) due to central venous catheter (CVC) placement is a rare but preventable complication which is potentially fatal. We describe a case highlighting unique patient characteristics which increase the risk of developing VAE.

Case description

A sixty-year-old gentleman was admitted to the hospital with dyspnea and altered mental status. His comorbidities include cancer of the neck and tongue, currently in remission, and schizophrenia. On presentation, he was found to be in acute respiratory failure, due to pneumonia, and required mechanical ventilation. Following extubation, his CVC was removed from the right internal jugular vein. While ambulating around the unit, he experienced a coughing fit and dizziness. He rapidly developed cardiopulmonary collapse requiring re-intubation and vasopressor support. Chest x-ray demonstrated a radiolucent column along the lateral aspect of the right neck. Due to concern for VAE, an echocardiogram was performed, revealing multiple air-bubbles in the right and left chambers of the heart.

Discussion

Our patient was predisposed to developing VAE due to the extensive radiation induced skin changes, from his cancer treatment, on the neck and upper thorax. This resulted in loss of underlying subcutaneous tissue and decreased skin pliability. He had a large, open puncture wound at the catheter site on his neck, probably resulting in air entry. Anxiety and agitation, due to schizophrenia, made it difficult to maintain our patient in a supine or Trendelenburg position following CVC removal. This case highlights the importance of recognizing patient factors that may increase the risk of VAE.

Intraoperative air embolism originating from a pulmonary vein

Air embolism entering the systemic arterial system originating from the pulmonary circuit itself is an extremely rare occurrence. We report the case of an 18-year-old female undergoing correction of an atrial septal defect, who had an air embolism that is believed to have originated from the right superior pulmonary vein. Although the exact mechanism of air entry remains a matter of speculation, several plausible hypotheses are proposed and discussed. Injury to a pulmonary vein may lead to air entry with migration to the left atrium and ultimately to systemic embolism.

Air embolism during insertion and replacement of tunneled dialysis catheters: a retrospective investigation of the effect of aerostatic sheaths and over-the-wire exchange

PURPOSE

To determine the impact of the introduction of aerostatic sheaths on air embolism (AE) events during tunneled dialysis catheter (TDC) insertion and to characterize such events occurring during over-the-wire exchange (OTWE).

MATERIALS AND METHODS

Between July 2001 and April 2013, 5,789 TDCs were placed, including 3,963 de novo placements, 1,811 OTWEs, and 15 tract recanalizations. There were 15 AE events reported, and the medical records of these patients were reviewed. The effect of aerostatic sheaths, introduced in July 2005, was compared with the period before their introduction; the same TDC design was used throughout.

RESULTS

Of the 15 AE events, 10 occurred during de novo placement (10 of 3,963 placement; 0.25%), 4 occurred during OTWE (4 of 1,811 placements; 0.22%), and 1 occurred during tract recanalization. With regard to aerostatic sheaths in de novo TDC placement, 4 of 1,174 (0.34%) AE events occurred before aerostatic sheath introduction, and 6 of 2,789 (0.22%) AE events occurred after aerostatic sheath introduction. These rates did not differ statistically (P = .5).

CONCLUSIONS

Use of aerostatic sheaths trended toward reducing AE events during de novo TDC placement. This trend was not statistically significant, probably owing to the rarity of AE despite the large sample size. Air embolism occurs during OTWE at a rate similar to de novo placement with aerostatic sheaths as well as during tract recanalization.

Recognising air embolism as a complication of vascular access

The insertion and maintenance of advanced vascular access devices is increasingly becoming the remit of advanced nurses. Understanding the potential for air embolism as a complication of this procedure, recognising and managing the signs and symptoms, and being able to apply preventative measures, are imperative to enhance patient safety. A range of outcomes can present from air embolism depending on the rate and volume of air entrained, from sub-clinical to death, so the application of expert knowledge and vigilance is essential to minimise risk. According the the available literature, supplemental oxygen administration appears to be the most effective treatment.

An unusual cause of ischemic stroke - Cerebral air embolism

Air embolism is a preventable, often undiagnosed but potentially treatable cause of ischemic stroke with a high morbidity and mortality. It is usually iatrogenic ocurring especially in patients in ICU setting. We describe the case and neuroimaging of a patient with ischaemic stroke due to air embolism during manipulation of central venous line. We also review the literature with respect to aetiology, incidence pathophysiology, diagnosis, and treatment options for venous and air embolism. Cerebral air embolism should be considered in patients with sudden neurological deterioration after central venous or arterial manipulations or certain neurological procedures. Prevention, as well as early diagnosis and management, may reduce morbidity and mortality.

Cerebral air embolism after central venous catheter self-extraction

Cerebral air embolism associated with central venous catheter insertion and removal is a rare but serious complication. There are many hypotheses on how air bubbles might be transported from the venous system to intracranial vessels. The literature has described how intra-cardiac defects transpulmonary passage and even retrograde flow of gas bubbles can explain this phenomenon. We present a case that illustrates the devastating effects of cerebral air embolism after a patient selfextracted his central venous catheter.

Trendelenburg position does not increase cross-sectional area of the internal jugular vein predictably

BACKGROUND

The Trendelenburg position is used to distend the central veins, improving both the success and safety of vascular cannulation. The purpose of this study was to measure the cross-sectional area (CSA) of the internal jugular vein (IJV) in three different positions using surface ultrasonography.

METHODS

Fifty-one subjects were enrolled. A Sono Site Titan 180 or M-Turbo portable ultrasound machine with a 10.5-mHz broadband linear surface probe was used. We measured the CSA of the IJV (at end-expiration at the level of the cricoid cartilage) in three positions: 15° reverse Trendelenburg, supine, and 15° Trendelenburg.

RESULTS

The mean CSA at 15° reverse Trendelenburg was 0.83 cm2 (SD, 0.86), in the supine position it was 1.25 cm2 (SD, 0.98), and at -15° Trendelenburg it was 1.47 cm2 (SD, 1.03). Moving from reverse Trendelenburg to supine, the CSA increased by 50%. In contrast, lowering the head to a Trendelenburg position increased the mean CSA by only 17%. Surprisingly, Trendelenburg positioning reduced the CSA in nine of the 51 subjects.

CONCLUSIONS

Trendelenburg positioning augments the CSA only modestly, on average, compared with the supine position, and in some patients it reduces the CSA.

TRIAL REGISTRATION

ClinicalTrials.gov; No.: NCT01099254; URL: www.clinicaltrials.gov.

Devastating cerebral air embolism after central line removal

BACKGROUND

Air embolism is a well-published complication arising from central venous catheter use. Literature and case studies provide information regarding clinical sequelae. Preventable mistakes still occur despite following what is considered appropriate protocol. This case report describes the neurological complications likely caused by a cerebral air embolism related to central venous catheter removal.

CASE

An 84-year-old man was admitted to the neuroscience critical care unit with acute stroke symptoms and seizures after removal of a central venous catheter.

CONCLUSION

There is an abundance of literature describing best practice, complications, and treatment of venous air embolism associated with central line catheter use. Utilization of central venous catheters is increasing. With increased utilization comes the responsibility to improve commonplace knowledge and ensure that practice guidelines and protocols are dependable and consistent.

Acute management of vascular air embolism

Vascular air embolism (VAE) is known since early nineteenth century. It is the entrainment of air or gas from operative field or other communications into the venous or arterial vasculature. Exact incidence of VAE is difficult to estimate. High risk surgeries for VAE are sitting position and posterior fossa neurosurgeries, cesarean section, laparoscopic, orthopedic, surgeries invasive procedures, pulmonary overpressure syndrome, and decompression syndrome. Risk factors for VAE are operative site 5 cm above the heart, creation of pressure gradient which will facilitate entry of air into the circulation, orogenital sex during pregnancy, rapid ascent in scuba (self contained underwater breathing apparatus) divers and barotrauma or chest trauma. Large bolus of air can lead to right ventricular air lock and immediate fatality. In up to 35% patient, the foramen ovale is patent which can cause paradoxical arterial air embolism. VAE affects cardiovascular, pulmonary and central nervous system. High index of clinical suspicion is must to diagnose VAE. The transesophgeal echocardiography is the most sensitive device which will detect smallest amount of air in the circulation. Treatment of VAE is to prevent further entrainment of air, reduce the volume of air entrained and haemodynamic support. Mortality of VAE ranges from 48 to 80%. VAE can be prevented significantly by proper positioning during surgery, optimal hydration, avoiding use of nitrous oxide, meticulous care during insertion, removal of central venous catheter, proper guidance, and training of scuba divers.

The impact of Trendelenburg position and positive end-expiratory pressure on the internal jugular cross-sectional area

BACKGROUND

Increasing the cross-sectional area (CSA) of the right internal jugular vein facilitates cannulation and decreases complications. Maneuvers such as the Trendelenburg tilt position and ventilation with a positive end-expiratory pressure (PEEP) may increase the CSA of the right internal jugular vein. We determined the changes in the CSA in response to different maneuvers.

METHODS

The CSA (cm(2)) of the right internal jugular vein was assessed in 50 anesthetized adult cardiothoracic surgery patients using 2-dimensional ultrasound. First, the CSA was measured in response to supine position with no PEEP (control condition, S0) and compared with 5 different randomly ordered maneuvers: (1) PEEP ventilation with 5 cm H(2)O (S5), (2) PEEP with 10 cm H(2)O (S10), (3) a 20 degrees Trendelenburg tilt position with a PEEP of 0 cm H(2)O (T0), (4) a 20 degrees Trendelenburg tilt position combined with a PEEP of 5 cm H(2)O (T5), and (5) a 20 degrees Trendelenburg tilt position combined with a PEEP of 10 cm H(2)O (T10).

RESULTS

All maneuvers increased the CSA of the right internal jugular vein with respect to the control condition S0 (all P < 0.05). S5 increased the CSA on average by 15.9%, S10 by 22.3%, T0 by 39.4%, T5 by 38.7%, and T10 by 49.7%.

CONCLUSION

In a comparison of the effectiveness of applying different PEEP levels and/or the Trendelenburg tilt position on the CSA of the right internal jugular vein, the Trendelenburg tilt position was most effective.

Long-term outcome of iatrogenic gas embolism

OBJECTIVE

To establish the incidence and long-term prognosis of iatrogenic gas embolism.

METHODS

This was a prospective inception cohort. We included all consecutive adults with proven iatrogenic gas embolism admitted to the sole referral academic hyperbaric center in Paris. Treatment was standardized as one hyperbaric session at 4 ATA for 15 min followed by two 45-min plateaus at 2.5 then 2 ATA. Inspired fraction of oxygen was set at 100% during the entire dive. Primary endpoint was 1-year mortality. All patients had evaluation by a neurologist, visual field tested by Goldman kinetic perimetry and brain MRI or CT scan at 6 months and 1 year.

RESULTS

From January 1993 to August 2004, 125 of 4,727,496 hospitalizations had proven iatrogenic gas embolism. The crude mortality was 25/119 (21%) at 1 year. Cardiac arrest at time of accident and ICU admission, and SAPS II of 33 or more were independent prognostic factors of 1-year mortality (OR = 4.39, 95% CI 1.46-12.20 and OR = 6.30, 1.71-23.21, respectively). Among ICU survivors, independent predictors of 1-year mortality were age (OR = 1.07, 1.01-1.14), Babinski sign (OR = 6.58, 1.14-38.20) and acute kidney failure (OR = 8.09, 1.28-51.21). Focal motor deficits (OR = 12.78, 3.98-41.09) and Babinski sign (OR = 6.76, 2.24-20.33) on ICU admission, and duration of mechanical ventilation of 5 days or more (OR = 15.14, 2.92-78.52) were independent predictors of long-term sequels.

CONCLUSIONS

Gas embolism complicates 2.65 per 100,000 hospitalizations, and is associated with high mortality and morbidity. Babinski sign on ICU admission is associated with poor prognosis.

Hyperbaric Oxygen Therapy in the Treatment of Post Cardiac Surgical Strokes – a Case Series and Review of the Literature

Strokes remain an uncommon but significant complication of cardiac surgery. Cerebral air embolism is the likely aetiology in the majority of cases. Hyperbaric oxygen therapy is the recognised treatment for cerebral air embolism associated with compressed air (SCUBA) diving accidents and is therefore also the standard of care for iatrogenic causes of air embolism. It follows that there is a logic in treating post-cardiac surgical stroke patients with hyperbaric oxygen.

The aim of this retrospective review was to examine the outcomes of 12 such patients treated in the Christchurch Hospital hyperbaric unit and to appraise the evidence base for the use of hyperbaric oxygen therapy in this setting.

Despite delays of up to 48 hours following surgery before the institution of hyperbaric oxygen therapy, 10 of the 12 patients made a full neurological recovery or were left with mild residual symptoms, with nine returning to their previous level of care. One patient remained hemiplegic and there was one early neurological death.

There is a paucity of prospective data in this area, but based on sound pathophysiological principles and clinical experience, we believe that patients suffering a stroke following open cardiac surgery should be considered for hyperbaric oxygen therapy.

What features of educational interventions lead to competence in aseptic insertion and maintenance of CV catheters in acute care? BEME Guide No. 15

BACKGROUND

Up to 6000 patients per year in England acquire a central venous catheter (CVC)-related bloodstream infection (Shapey et al. 2008 ). Implementation of Department of Health guidelines through educational interventions has resulted in significant and sustained reductions in CVC-related blood stream infections (Pronovost et al. 2002), and cost (Hu et al. 2004 ).

AIM

This review aimed to determine the features of structured educational interventions that impact on competence in aseptic insertion technique and maintenance of CV catheters by healthcare workers.

METHODS

We looked at changes in infection control behaviour of healthcare workers, and considered changes in service delivery and the clinical welfare of patients involved, provided they were related directly to the delivery method of the educational intervention.

RESULTS

A total of 9968 articles were reviewed, of which 47 articles met the inclusion criteria.

CONCLUSIONS

Findings suggest implications for practice: First, educational interventions appear to have the most prolonged and profound effect when used in conjunction with audit, feedback, and availability of new clinical supplies consistent with the content of the education provided. Second, educational interventions will have a greater impact if baseline compliance to best practice is low. Third, repeated sessions, fed into daily practice, using practical participation appear to have a small, additional effect on practice change when compared to education alone. Active involvement from healthcare staff, in conjunction with the provision of formal responsibilities and motivation for change, may change healthcare worker practice.

Acute management of vascular air embolism

Vascular air embolism (VAE) is known since early nineteenth century. It is the entrainment of air or gas from operative field or other communications into the venous or arterial vasculature. Exact incidence of VAE is difficult to estimate. High risk surgeries for VAE are sitting position and posterior fossa neurosurgeries, cesarean section, laparoscopic, orthopedic, surgeries invasive procedures, pulmonary overpressure syndrome, and decompression syndrome. Risk factors for VAE are operative site 5 cm above the heart, creation of pressure gradient which will facilitate entry of air into the circulation, orogenital sex during pregnancy, rapid ascent in scuba (self contained underwater breathing apparatus) divers and barotrauma or chest trauma. Large bolus of air can lead to right ventricular air lock and immediate fatality. In up to 35% patient, the foramen ovale is patent which can cause paradoxical arterial air embolism. VAE affects cardiovascular, pulmonary and central nervous system. High index of clinical suspicion is must to diagnose VAE. The transesophgeal echocardiography is the most sensitive device which will detect smallest amount of air in the circulation. Treatment of VAE is to prevent further entrainment of air, reduce the volume of air entrained and haemodynamic support. Mortality of VAE ranges from 48 to 80%. VAE can be prevented significantly by proper positioning during surgery, optimal hydration, avoiding use of nitrous oxide, meticulous care during insertion, removal of central venous catheter, proper guidance, and training of scuba divers.

Venous air embolism through central venous access

An 25-year-old man was buried by an avalanche during off-slope skiing. He was rescued by his companions and resuscitated by mouth-to-mouth ventilation. The emergency physician from a helicopter based emergency medical service placed two venous lines in both external jugular veins and secured the airway with a tracheal tube. When transferred to the emergency department an additional central venous catheter was inserted via his right femoral vein. The subsequent computed tomography scan revealed several small air bubbles adjacent to the endothelium of the brachiocephalic vein. In an experimental setting, it was shown that air could enter the circulation via a central venous catheter within a few seconds, but measured values of embolising air were smaller than the calculated values when applying the law of Hagen-Poiseuille. Nevertheless, it is important to keep the lumens of a central venous catheter filled with saline before any manipulation in order to prevent or attenuate venous air embolism.

Elective removal of cuffed central venous catheters in children

BACKGROUND

Subcutaneously tunneled, cuffed central venous catheters (CVCs) are commonly used in children undergoing cytotoxic chemotherapy or hematopoietic stem-cell transplantation. When their use is no longer indicated or precluded by mechanical or infectious complications, CVCs have to be removed. General instructions on how cuffed CVC should be removed are available in the medical texts but none is adapted for use in children.

MATERIALS AND METHODS

A literature search from the MEDLINE and EMBASE to identify articles describing the procedure of removing CVC or complications arising from the procedure was carried out.

RESULTS

Specific guidance on the removal of CVC in children was not found. Venous air embolism appeared to be the most common complication associated with catheter removal but none involved pediatric patients. On the other hand, three out of the five incidents of catheter fracture with or without embolization happened in children.

CONCLUSION

Further studies are needed to define the optimal management of CVC removal in pediatric patients. A sequence of positioning the child, use of sedation, dissecting out the cuff, pulling off the catheter, closing the exit wound, and handling of the removed catheter is suggested.

Humming Is as Effective as Valsalva’s Maneuver and Trendelenburg’s Position for Ultrasonographic Visualization of the Jugular Venous System and Common Femoral Veins

STUDY OBJECTIVE

The purpose of this study is to compare ultrasonographic visualization of the jugular and common femoral veins by using a novel technique (humming) and 2 conventional techniques (Valsalva's maneuver and Trendelenburg's position). The Valsalva's maneuver and Trendelenburg's position are common methods for producing venous distention, aiding ultrasonographically guided identification and cannulation of the jugular and common femoral veins. We hypothesize that humming is as effective as either Valsalva's maneuver or Trendelenburg's position for distention and ultrasonographic visualization of these procedurally important blood vessels. Herein, we investigate a new method of venous distension that may aid in the placement of central venous catheters by ultrasonographic guidance.

METHODS

Healthy, normal volunteers aged 28 to 67 years were enrolled. Each subject's internal jugular, external jugular, and common femoral veins were measured in cross-section by ultrasonograph during rest (baseline), humming, Valsalva's maneuver, and Trendelenburg's position. Three measurements were recorded per observation in each position. Subjects were used as their own controls, and measurements were normalized to percentage increase in diameter during each maneuver or position for later comparison.

RESULTS

The study population consisted of 7 subjects, with a mean age of 47 years. Cross-sectional area was calculated for each vessel in 3 groups: baseline/control, Valsalva, Trendelenburg, and humming. The mean percentage change (+/-SD) relative to baseline cross-sectional area of the jugular vessels for each subject were external jugular vein: humming 134%+/-25% (95% confidence interval [CI] 124.9% to 146.9%), Valsalva 136%+/-23% (95% CI 121.3% to 147.5%), Trendelenburg 137%+/-32% (95% CI 120.7% to 156.9%); internal jugular vein: humming 137%+/-27% (95% CI 119.4% to 148.2%), Valsalva 139%+/-24% (95% CI 122.4% to 148.7%), Trendelenburg 141%+/-35% (95% CI 116.5% to 156.5%); common femoral vein: humming 131%+/-15% (95% CI 120.4% to 139.1%), Valsalva 139%+/-18% (95% CI 127.9% to 150.4%), Trendelenburg 132%+/-24% (95% CI 113.3% to 142.9%).

CONCLUSION

All 3 maneuvers distended the external jugular, internal jugular, and common femoral veins compared to baseline. There was no important difference in magnitude of cross-sectional area between any of the 3 maneuvers when compared with one another. Humming shares many physiologic similarities to Valsalva's maneuver and may be more familiar and easier to perform during procedures such as ultrasonographically guided central venous catheter placement and insertion of external jugular intravenous catheters.

Central venous catheterization

OBJECTIVE

To provide current information related to central venous catheterization.

DESIGN

Review of literature relevant to central venous catheterization and its indications, insertion techniques, and prevention of complications.

RESULTS

Central venous catheterization can be lifesaving but is associated with complication rates of approximately 15%. Operator experience, familiarity with the advantages and disadvantages of the various catheterization sites, and strict attention to detail during insertion help in reducing mechanical complications associated with catheterization. Strict aseptic technique and proper catheter maintenance decrease the frequency of catheter-related infections.

CONCLUSIONS

Appropriate catheter and site selection, sufficient operator experience, careful technique, and proper catheter maintenance with removal as soon as possible are associated with optimal outcome.

[Venous gas embolism from pleurovenous fistula]

We report the case of an iatrogenic gas embolism related to a subclavian vein catheterization complicated by a preexisting partial pneumothorax. Catheterization was indicated because of a septic shock due to nosocomial pneumonia. Five days after the catheterization, the haemodynamics and gas exchanges of the patient worsened. A transthoracic echography showed gas embolism in the right heart related to a right partial pneumothorax. A leak between the pleura and the left subclavian vein was diagnosed. The insertion of a chest tube stopped the airflow, by suppressing the pneumothorax.

Patient safety in intensive care: results from the multinational Sentinel Events Evaluation (SEE) study

OBJECTIVE

To assess on a multinational level the prevalence and corresponding factors of selected unintended events that compromise patient safety (sentinel events) in intensive care units (ICUs).

DESIGN

An observational, 24-h cross-sectional study of incidents in five representative categories.

SETTING

205 ICUs worldwide

MEASUREMENTS

Events were reported by intensive care unit staff members with the use of a structured questionnaire. Both ICU- and patient-related factors were assessed.

RESULTS

In 1,913 adult patients a total of 584 events affecting 391 patients were reported. During 24 h multiple errors related to medication occurred in 136 patients; unplanned dislodgement or inappropriate disconnection of lines, catheters, and drains in 158; equipment failure in 112; loss, obstruction or leakage of artificial airway in 47; and inappropriate turn-off of alarms in 17. Per 100 patient days, 38.8 (95% confidence interval 34.7-42.9) events were observed. In a multiple logistic regression with ICU as a random component, the following were associated with elevated odds for experiencing a sentinel event: any organ failure (odds ratio 1.13, 95% confidence interval 1.00-1.28), a higher intensity in level of care (odds ratio 1.62, 95% confidence interval 1.18-2.22), and time of exposure (odds ratio 1.06, 95% confidence interval 1.04-1.08).

CONCLUSIONS

Sentinel events related to medication, indwelling lines, airway, and equipment failure in ICUs occur with considerable frequency. Although patient safety is recognised as a serious issue in many ICUs, there is an urgent need for development and implementation of strategies for prevention and early detection of errors.

Aerostasis during Central Venous Access: Updates in Protective Sheaths

PURPOSE

Air emboli (AE) complicating central venous catheter (CVC) placement are rare but potentially fatal events. Building on earlier experience, the authors conducted in vitro testing of the aerostatic properties of newly designed protective sheaths.

MATERIALS AND METHODS

The standard peel-away sheath, the previously studied sliding-valve sheath, and newer fixed-valve and double-valved sheaths were evaluated. Aerostatic stability of the sheaths was evaluated by measuring air flow into the model under standard and stressed conditions. In addition, volumes of AE created during simulated CVC insertion through the sheaths were determined.

RESULTS

Under physiologic conditions, significantly smaller volumes of AE occurred with a pinch 2 inches from the sheath hub relative to a pinch at 1 inch. Sliding-, fixed-, and double-valve sheaths yielded leak rates of 0.05 +/- 0.05 mL/sec, 0.06 +/- 0.05 mL/sec, and 0.08 +/- 0.07 mL/sec, respectively. Under stress, protective sheath leak rates increased to 1.8 +/- 0.4 mL/sec, 1.6 +/- 0.5 mL/sec, and 1.8 +/- 0.4 mL/sec, respectively. Use of a double-valved sheath demonstrated no significant difference in leak rates under standard and stressed conditions. In most cases, protective sheaths yielded significantly smaller AE than control sheaths. In comparison of protective sheaths, AE volumes during CVC insertion for sliding-, fixed-, and double-valved sheaths were 22.8 +/- 4.5 mL, 16.6 +/- 7.3 mL, and 10.8 +/- 4.5 mL, respectively. Double-valved sheaths yielded significantly smaller AE volumes than did sliding-valve sheaths (P < .01).

CONCLUSIONS

In most standard situations, AE volumes and aerostatic stability of protective sheaths tested favorably in comparison with control sheaths. When some sheaths were stressed, their aerostatic properties failed. In a comparison of the three protective sheaths in standard and stressed conditions, the double-valved sheath fared better than the sliding and fixed-valve sheaths.