39 Reducing Errors in Cardiac Anesthesiology

T. Andrew Bowdle, MD, PHD, Mark Edwards, MBCHB, FANZCA, Karen B. Domino, MD, MPH

1. Evidence-based recommendations for reducing complications from central catheters include use of maximum sterile barriers, real-time ultrasound guidance during central catheter insertion and selective use of antibiotic-impregnated central venous catheters.

2. Most cases of cardiac tamponade caused by central venous catheters should be preventable by taking a chest x-ray following placement to confirm that the position of the tip of the catheter is outside the pericardial sac and parallel to the walls of the vena cava.

3. Evidence suggests that the most reliable method for avoiding inadvertant cannulation of an artery during central venous catheter insertion is measurement of the intravascular pressure by use of a transducer or manometry.

4. The reported risk of intraoperative awareness during cardiac surgery is around 0.4 –1%, a 10- fold increase compared with the overall level of around 0.1– 0.2%.

5. Evidence suggests that the use of processed EEG to monitor the depth of anesthesia may significantly reduce the risk of intraoperative awarness.

7. Anecdotal evidence suggests that infusion pumps with advisory systems known as “error reduction systems” can significantly reduce drug administration errors resulting from incorrect manual entry of dosing information at the point of care; these pumps utilize predefined dosing limits and warn the practitioner if the dosing parameters that are entered at the point of care will result in an inappropriate dose.

8. Anecdotal evidence suggests that bar coding of patient identifiers, drugs, and infusion pumps at the point of care may significantly reduce the rate of errors related to drug administration.

9. Evidence suggests that fatigue may contribute significantly to errors, although specific studies in cardiac anesthesiology are lacking.

10. The American Society of Anesthesiologists Closed Claims database contains 327 claims related to cardiac anesthesia, with an increased proportion of claims for brain damage, stroke, and awareness during anesthesia and decreased proportion of claims for airway injury compared with 4986 other claims for other surgical procedures under general anesthesia.

Although the safety of anesthesiology has improved over recent years, with an attributable mortality on the order of 1 in 53,500 anesthetics,* errors still occur. Like other medical practitioners, anesthesiologists are prone to human error. The complex arena of cardiac anesthesia provides an opportunity for making just about any of the errors that can possibly be made by an anesthesiologist. It is just because of the complexity and the high stakes encountered in the cardiac anesthesia environment that cardiac anesthesiologists should be most interested in methods for reducing errors. This is particularly relevant now as regulatory agencies and the public in general have become acutely aware of medical errors since the publication of the Institute of Medicine’s landmark report on the subject.¹ In response, initiatives have been developed by a wide range of organizations with the intention of reducing errors and improving safety for surgical patients. These have been aimed at the entire surgical patient population (e.g., the World Health Organization’s safe surgery saves lives checklist)^2,³ and, more specifically, at cardiac surgical patients. The Society of Cardiovascular Anesthesiologists (SCA) Foundation has undertaken an initiative called Flawless Operative Cardiovascular Unified Systems (FOCUS). They intend to take a multidisciplinary approach to identifying and mitigating hazards. One of the interventions they envision developing is peer-to-peer assessment. An overview of the project and an outline of their plan have been recently published.⁴

The purpose of this chapter is not to catalogue the errors that may be made in cardiac anesthesia, but rather to point to specific areas in which there are data in support of methods for significantly reducing errors. These specific areas are:

1. Errors involving the placement of central catheters

2. Errors in the assessment of anesthetic depth that may result in intraoperative awareness

3. Errors involving the process of administering drugs, such as giving the wrong drug (The principles also apply to errors in administering blood products.)

In each of these categories of errors, anesthesiologists will see that there are methods that should enable them to reduce error. The reader also may find previous descriptions of mechanisms of error in anesthesia useful.⁵^–⁷

Errors involving the placement of central catheters

Central catheters have long been regarded as dangerous by practitioners, manufacturers, and the U.S. Food and Drug Administration. (FDA). Complications from central catheters have been reviewed recently.⁸^–¹¹ Hall and Russell¹² have authored an editorial that provides, in three pages, a concise but complete description of safe practices for placing central catheters; if the reader has time to read only a single article on this topic, it is highly recommended. This section concentrates on errors related to the internal jugular vein (IJV) route of central catheter insertion because this is the most common insertion route used by cardiac anesthesiologists (Box 39-1).

Agency for Healthcare Research and Quality

The Agency for Healthcare Research and Quality (AHRQ) is a part of the Public Health Service of the federal Department of Health and Human Services. The mission of the AHRQ is “to support research designed to improve the quality, safety, efficiency, and effectiveness of healthcare for all Americans.” In 2001, AHRQ published a document entitled, “Making Health Care Safer: A Critical Analysis of Patient Safety Practices,” an evidence-based review of practices intended to improve patient safety.¹³ There were 11 practices that were most highly rated of 79 practices that were reviewed in detail, based on the strength of evidence supporting their widespread implementation. These included three practices related to the management of central venous catheters (CVCs):

1. Use of maximum sterile barriers while placing central intravenous catheters to prevent infections

2. Use of real-time ultrasound guidance during central catheter insertion to prevent complications

3. Use of antibiotic-impregnated CVCs to prevent catheter-related infections

These recommendations clearly have implications for the practice of cardiac anesthesiology. Before examining these recommendations in more detail, the authors will take a broader look at complications from central catheters.

Central Venous Catheter Complications and the American Society of Anesthesiologists Closed Claims Project Database

The American Society of Anesthesiologists (ASA) Closed Claims Project database is a standardized collection of case summaries of adverse anesthesia-related outcomes derived from closed liability claims collected from 35 insurance organizations. Although it is impossible to know the true incidence of the adverse events that appear in the Closed Claims Project database (there is no “denominator” for the database), this relatively large set of cases may reveal patterns of events that contribute to patient injury and subsequent legal action, which would not be possible to discern by looking at individual cases.

The authors’ review of the Closed Claims Project database confirmed the hazards previously associated with central catheters.¹⁴ Among the 6449 claims reported through December 2002, there were 110 claims for injuries related to CVCs (1.7%). Claims related to CVCs had a high severity of patient injury with an increased proportion of death (47%) compared with other claims in the database (29%; P < 0.01).

The main results of the review are shown in Table 39-1. Inspection of this table reveals that the most important injuries, both in terms of numbers and death rate, are cardiac tamponade and injuries to major arteries and veins (combining “carotid artery puncture/cannulation,” “hemothorax,” and “miscellaneous other vessel injury”), representing 16 of 110 and 39 of 110 cases, respectively, not including pulmonary artery (PA) injuries. This impression is reinforced when the injuries reported after 1990 are compared with those reported before 1990 (Figure 39-1). Since 1990, most injuries have been accounted for by vascular injuries.

TABLE 39-1 Central Catheter-Related Injuries from the American Society of Anesthesiologists Closed Claims Project Database

Type of Complication	n	Death, n (%)
Wire/catheter embolus	20	1 (5)*
Cardiac tamponade	15	12 (80)*
Carotid artery injury	14	5 (36)
Hemothorax	14	12 (92)*
Pneumothorax	12	2 (15)*
Miscellaneous vessel injury	7	2 (29)
Pulmonary artery rupture	6	6 (100)
Hydrothorax	5	2 (40)
Air embolism	4	3 (75)
Fluid extravasation in neck	4	2 (50)
Cardiac arrhythmia	1	0 (0)

* P < 0.05 compared with other complications.

Data from Domino KB, Bowdle TA, Posner KL, et al: Injuries and liability related to central vascular catheters. Anesthesiology 100:1411–1418, 2004.

Figure 39-1 Central catheter-related claims or injuries from the American Society of Anesthesiologists (ASA) Closed Claims Project database. A greater proportion of claims from 1989 to 1999 involved complications related to access (i.e., mostly vascular injuries). *P < 0.05, 1994–1999 compared with other periods.

Although a great deal of attention has been paid to PA injuries caused by pulmonary artery catheters (PACs), it is interesting that they make up only 7 of 110 central catheter-related cases in the Closed Claims Project database.¹⁴ In addition, the anecdotal literature suggests that injuries to pulmonary arteries by PACs are sporadic and probably not related to specific errors or problems with technique. Although highly lethal¹⁵ and certainly to be feared, probably the main thing the practitioner can do to reduce the liklihood of PA injury is to avoid using a PAC in the first place. The appropriate use of PACs has been highly contentious,¹⁶^–²⁹ and because the literature is not clear regarding the safety of PACs, they will not be considered further in this chapter (see Chapter 14).

Preventing Cardiac Tamponade

Cardiac tamponade from a central catheter occurs when the tip of a CVC is allowed to remain in the right atrium, or up against the wall of the vena cava at an acute angle, resulting in perforation of the atrium or cava. Perforation can occur immediately after placement or, more commonly, after hours to days. This problem has been documented by numerous case reports ³⁰^–³⁶ and accounted for 16 of 110 cases of central catheter-related claims in the ASA Closed Claims Project database; 13 of these 16 cases resulted in death.¹⁴ Perforation can occur immediately after placement, or more commonly after hours to days. Package inserts in CVC kits contain vigorous warnings against placing a CVC into the right atrium or with the CVC tip at an acute angle to the superior vena cava (SVC; Figure 39-2). Despite some controversy, most authors have concluded that the catheter tip should be outside of the pericardial sac and parallel to the walls of the vena cava.³⁷ It is a widely accepted practice to obtain a chest radiograph after CVC placement, usually in the recovery room or intensive care unit (ICU) after surgery. This allows the position of the catheter tip to be assessed and adjusted if necessary (Figures 39-3 and 39-4).^38,³⁹ The carina is a useful structure for assessing the position of the catheter tip on the chest radiograph because the vena cava is outside the pericardium at the level of the carina.^40,⁴¹ Locating the catheter tip at or above the level of the carina should ensure that the catheter tip lies outside of the pericardial sac. The carina may be a better landmark than the radiographic cardiac sillouette because several centimeters of the SVC may lie inside the pericardium but outside of the radiographic cardiac sillouette.^40,⁴¹ Kwon et al⁴² made measurements of the SVC in vivo in 61 cardiac surgery patients and found that approximately half of the length of the SVC is within the pericardium. Particular caution should be exercised when catheters are placed from the left side (left internal jugular or subclavian veins) that the catheter tip either remains within the innominate vein³⁷ or makes the turn into the SVC, ending with the tip parallel to the cava and not abutting the wall of the cava at an acute or right angle. Many catheters can be inserted to a depth sufficient to reach the right atrium (Figure 39-5), and this should be avoided by placing the CVC only to a depth of 10 to 12 cm from the right IJV approach in the typical adult. Because of anatomic variation, the placement should be confirmed by chest radiograph. Alternative approaches to verifying the position of the catheter tip include intravascular electrocardiography⁴³ and TEE.⁴⁴ An interesting editorial regarding tip location of CVCs is available.³⁷

Figure 39-2 Package insert of a central venous catheter (CVC) kit.

Figure 39-3 Routine chest radiograph taken in the recovery room showed the central venous catheter pointing toward the wall of the superior vena cava at an acute angle. Such positioning may increase the risk for perforation of the vena cava by the tip of the catheter. This catheter was repositioned as shown in Figure 39-4.

Figure 39-4 The central venous catheter shown in Figure 39-3 was repositioned so that the catheter was parallel to the walls of the superior vena cava. This position is thought to be safer than the original position shown in Figure 39-3 in which the catheter was pointed toward the wall of the vena cava at an acute angle.

Figure 39-5 A central venous catheter is shown with markings to indicate the distance to the tip of the catheter. The dark band is 10 cm from the tip of the catheter. Inserting this catheter as far as possible will result in the tip being 16 cm from the skin puncture site. If this catheter were inserted 16 cm into the right internal jugular vein from a skin puncture site low in the neck, the tip of the catheter could easily be in the right atrium. Allowing the catheter tip to reside in the right atrium may result in perforation of the atrial wall. Before obtaining a chest radiograph to confirm the location of the catheter tip, limiting the insertion to 10 to 12 cm for the right internal jugular approach in a typical adult patient will usually avoid right atrial placement.

Preventing Vascular Injury

Vascular injury related to central catheters is conveniently divided into injuries to cervical arteries and injuries to intrathoracic veins or arteries. The mechanisms of injury and the methods of prevention are different in each category.

Preventing Injuries to Arteries

The most common injury to arteries is related to puncture or cannulation of the carotid artery. Puncturing the carotid artery with a small needle, although undesirable, does not generally produce any harm. However, if the arterial puncture is not recognized and a guidewire is placed into the artery and followed with a CVC or PAC introducer sheath, there is the possibility of a major problem. Pressure waveform measurement and ultrasound are two methods commonly used to reduce the chances of injury to the carotid artery.

Pressure Waveform Measurement

In 1983, Jobes et al ⁴⁵ reported on a retrospective study of 1021 attempts at IJV access in which there were 43 arterial punctures; 5 of 43 arterial punctures were unrecognized, resulting in the placement of 8-French introducer sheaths into an artery and resulting in one fatality from hemothorax. Subsequently, these investigators performed a prospective trial of 1284 attempts at IJV access in which they measured a pressure waveform from the vessel before inserting the guidewire. Before measuring the pressure waveform, a clinical assessment was made as to whether the needle was in an artery or vein, based on the usual criteria of color and pulsatility. There were 51 arterial punctures, 10 of which were incorrectly identified as being venous based on color and pulsatility but were determined to be arterial from the pressure waveform. Thus, 10 inadvertant cannulations of the carotid artery were avoided by pressure waveform monitoring.

Ezaru et al ⁴⁶ recently published a retrospective analysis of 9348 CVC placements requiring mandatory use of manometry to verify venous access. In a single institution, over a 15-year period, there were no cases of arterial injury. During the final year of the study, 511 catheters were placed. Arterial puncture (defined as placement of an 18-gauge finder needle or catheter into an artery) occurred in 28 patients (5%). Arterial puncture was recognized from color and pulsatility in 24 cases, without manometry; but in four cases, the arterial placement was only recognized with manometry. Despite these findings, and the anecdotal experiences of many anesthesiologists who have placed catheters and sheaths into carotid arteries, many anesthesiologists continue to rely on color and pulsatility of blood in the hub of a needle to differentiate arterial from venous puncture.

The pressure waveform can be most conveniently measured using the setup shown in Figure 39-6.⁴⁷ This setup has the advantage of giving the pressure waveform without the need to disconnect the syringe and connect monitoring tubing to the needle, with the risk for dislodging the needle from the vein. An alternative method used by many anesthesiologists uses manometry. The syringe is disconnected from the needle and a length of tubing is connected, allowed to fill with blood, and then held vertically to identify the pressure from the height of the blood column. There are no data comparing these alternative methods of pressure measurement; however, the manometry technique requires an additional step to connect the manometry tubing. A novel approach to measuring a pressure waveform with a miniature, single-use in-line pressure transducer is illustrated in Figure 39-7.

Figure 39-6 This setup is used by the authors for obtaining a pressure waveform during central venous catheter (CVC) placement. The T-shaped adapter and a length of pressure tubing are added to a standard CVC kit, and the device is assembled as shown using the needle and syringe found in the kit. The pressure tubing is handed off to the assistant who connects it to a transducer and flushes the system. When blood is aspirated into the syringe indicating entry into the blood vessel, inspection of the waveform on the monitor immediately allows differentiation between artery and vein. Once the presence of a venous waveform is confirmed, the syringe or T-adapter is removed and the wire is inserted.

Figure 39-7 The Compass Vascular Access Device manufactured by Mirador Biomedical, Inc.

This single-use device measures the intravascular pressure, which is displayed digitally and also as an analog representation of the pressure waveform. A wire may be passed either through the syringe connection port after removing the syringe or through a separate valved port. The pressure may be measured continuously during the placement of the wire.

Ultrasound Guidance

The availability of relatively inexpensive, portable ultrasound equipment led to the application of two-dimensional ultrasound imaging to guide CVC placement. Ultrasound imaging allows the presence of the IJV to be confirmed, its patency can be demonstrated, and its anatomic relation to the carotid artery can be defined. Real-time use can guide needle placement into the vein and confirm the presence of a wire in the vein. Troianos et al ⁴⁸ first reported the use of ultrasound-guided central vascular access in the anesthesia literature in 1991. Their prospective, randomized study of ultrasound guidance versus the traditional landmark method found a greater overall success rate, a greater success rate on the first attempt, and reduced rate of arterial puncture with ultrasound guidance. Numerous studies of ultrasound guidance and two major meta-analyses have appeared subsequently. As noted earlier, a review commissioned by the AHRQ strongly advocated the use of ultrasound guidance.¹⁰ In the United Kingdom, the National Institute of Clinical Excellence (NICE) recommends routine use of ultrasound for central venous catheterization.*

The two major meta-analyses of ultrasound guidance concluded that ultrasound guidance was superior to landmarks for overall success rate, a greater success rate on the first attempt, and reduced complications from arterial puncture for the IJV approach.^49,⁵⁰ The advantage of ultrasound guidance for the subclavian approach was less clear.

The authors examined CVC complications from the ASA Closed Claims Project database in an attempt to determine whether the use of pressure waveform monitoring or ultrasound guidance would have prevented the complications. This is clearly inferential; nevetheless, it is interesting that nearly half (48/110) of the complications were judged to be possibly preventable by the use of either pressure waveform monitoring or ultrasound guidance, only by ultrasound guidance, only by pressure waveform monitoring, or by chest radiograph (Table 39-2).¹⁴

TABLE 39-2 Potential Effect of Ultrasound Guidance or Pressure Waveform Monitoring on Central Venous Catheter–Related Injuries from the American Society of Anesthesiologists Closed Claims Project Database

Possibly preventable by either ultrasound guidance or pressure waveform monitoring (n =19)
Carotid artery puncture/cannulation	16
Hemothorax	1
Wire/catheter embolus	1
Miscellaneous other vessel injury	1
Possible preventable by pressure waveform monitoring only (n = 6)
Miscellaneous other artery injury	5
Hemothorax	1
Possibly preventable by ultrasound guidance only (n = 9)
Hemothorax	4
Pneumothorax	4
Miscellaneous other vessel injury	1
Possibly preventable by chest radiograph (n = 14)
No chest radiograph taken (n = 7)
Carotid tamponade	2
Wire/catheter embolus	1
Pneumothorax	4
*Misread, not read, or inappropriate action taken (n = 7)*
Cardiac tamponade	4
Wire/catheter embolus	3

The cases related to central venous catheters from the ASA Closed Claims database were examined to determine whether the use of ultrasound guidance, pressure waveform monitoring, or chest radiograph (after placement) might have prevented the injuries. A total of 48 of 110 injuries were thought to be potentially preventable by these means.

Data from Domino KB, Bowdle TA, Posner KL et al: Injuries and liability related to central vascular catheters. Anesthesiology 100:1411–1418, 2004.

Wigmore et al ⁵¹ reported their experience in a single tertiary referral center in Britain after implementation of the National Institute of Clinical Excellence guideline. This is a particularly interesting study because it illustrates the effect in a single center of attempting to implement a national guideline. During the study, adoption of ultrasound guidance increased from less than 10% to more than 80%. There were 19 of 152 complications during a preguideline audit, 18 of which involved the landmark technique without ultrasound guidance. After introduction of the guideline, there were 13 of 286 complications, 10 from cases in which only the landmark technique was used (8.7%) and 3 from cases in which ultrasound guidance was used (1.7%), an absolute risk reduction of 6.9% with ultrasound. Complications consisted of arterial punctures, neck hematomas, and a pneumothorax. There was also a significant reduction in failed insertions with ultrasound guidance (7/115 for the landmark group and 1/169 for the ultrasound group; P < 0.01).

Recently, Hosokawa et al ⁵³ have demonstrated the utility of ultrasound guidance in neonates and infants less than 7.5 kg. They compared ultrasound guidance with the traditional anatomic landmark method, and later they compared ultrasound guidance for skin marking (without live ultrasound during needle puncture) with live ultrasound guidance. There was a 97% success rate for ultrasound guidance compared with a 62% success rate for the anatomic landmark method.⁵² Live ultrasound compared with ultrasound for skin marking (without live ultrasound during needle puncture) resulted in significantly faster cannulation and fewer needle passes.⁵³ Fewer than three attempts at puncture were made in 100% of patients in the live ultrasound group compared with 74% of patients in the ultrasound for skin marking group.

An important caveat for the use of ultrasound guidance is that the needle and/or wire may not always be visualized in the vein, depending on the type of ultrasound equipment used and the skill of the operator. Although it may be possible to visualize the tip of the needle with ultrasound,⁵⁴ because of the tomographic nature of an ultrasound beam, it may be difficult to distinguish the shaft of the needle from the tip. Needles with a special echogenic surface that may enhance ultrasound visualization are available (see Chapter 14).

Anecdotal experience has shown that despite the use of ultrasound guidance and the appearance that the needle is pointed toward the vein, the needle may hit the artery, particularly when the artery is posterior to the vein. A guidewire can often be visualized more reliably than a needle; however, it is preferable to correctly identify the vessel before placing the guidewire because blindly inserting a guidewire into the carotid or other major artery is undesirable. If the needle and/or wire is not definitely visualized in the vein, measurement of a pressure waveform in conjunction with ultrasound guidance is strongly recommended. In the authors’ practice, ultrasound guidance and pressure waveform monitoring are both available, and at least one technique is used routinely after vessel puncture to confirm that the vein has been entered. One important caveat is the possibility that the needle can be inadvertantly moved after confirmation of venous puncture by ultrasound or pressure waveform and subsequently enter an artery, which may result in cannulation of the artery. This can be avoided by puncturing the vessel with a small (i.e., 18-gauge) angiocatheter instead of a needle before measuring a pressure waveform because the angiocatheter once inserted is less likely to be dislodged. Alternatively, visualizing the wire in the vein with ultrasound can serve as a final check of correct venous placement.

Given the abundance of data in favor of the use of ultrasound guidance, it is reasonable to consider the use of ultrasound guidance to be the “preferred method of insertion.”⁵⁵ Interestingly, several surveys have found relatively low rates of using ultrasound guidance. A survey of pediatric anesthesiologists in the United Kingdom found that only 39% used ultrasound routinely.⁵⁶ A more recent survey of pediatric anesthesiologists in the United Kingdom found that only 26% always used ultrasound.⁵⁷ Another recent survey in the United Kingdom of senior members of the Association of Anaesthetists of Great Britain and Ireland found that only 27% used ultrasound guidance as their first choice.⁵⁸ A survey of members of the SCA found that only 15% always used ultrasound.⁵⁹ A shortage of suitable ultrasound equipment is sometimes a reason for not using ultrasound guidance. A study in the United Kingdom found that 86% of anesthetic departments had ultrasound equipment for CVC placement⁶⁰; however, Bailey et al⁵⁹ found that 33% of anesthesiologists in their survey of members of the SCA never or almost never had ultrasound equipment available.

Preventing Injuries to Intrathoracic Arteries or Veins

Pressure waveform monitoring and ultrasound guidance are valuable primarily for avoiding injury to arteries, especially to the carotid artery during attempted IJV cannulation. There is another category of vascular injury that is not addressed by pressure waveform monitoring or ultrasound guidance, which is injury to intrathoracic veins or arteries, made clear from anecdotal reports and from the ASA Closed Claims Project database, which contains 15 cases of hemothorax, 14 of which were fatal. A large puncture or tear in a large intrathoracic vein or artery can bleed profusely and may be difficult to repair surgically in time to prevent exsanguination. Although the mechanism of these injuries is not known in every case, certain mechanisms appear to be particularly likely.

Guidewires can take a circuitous route so that when devices are advanced over them, the device may trap the wire up against the wall of the vein, and if the device is stiff enough, perforation of the vein may occur (Figure 39-8).⁶¹ The inner dilators of PAC introducer sheaths are very stiff and may be particularly likely to cause this kind of perforation. The dilator is intended to create a passage through the skin and fascia but has no useful role once the device has entered the vein. Therefore, it is prudent to advance the dilator the minimum distance necessary to reach the vein and no farther. The introducer sheath may then be advanced over the dilator into the vein.

Figure 39-8 A hypothetical mechanism of perforation of a great vein inside the chest (in this case, the innominate vein-vena cava junction) by a dilator (the pulmonary artery catheter introducer sheath, normally loaded onto the dilator, is not shown for simplicity) is shown. The dilator traps the guidewire against the wall of the vein and then perforates the vein as it is advanced. Numerous anecdotal reports of injuries could be explained by this mechanism. Direct observation of the progress of the insertion of the wire and intravascular device under fluoroscopy may be useful for avoiding this potentially fatal complication. GW, guidewire; IV, innominate vein; LIJV, left internal jugular vein; LSV, left subclavian vein; RIJV, right internal jugular vein; RSV, right subclavian vein; SVC, superior vena cava.

(From Oropello JM, Leibowitz AB, Manasia A, et al: Dilator-associated complications of central vein catheter insertion: Possible mechanisms of injury and suggestions for prevention. J Cardiothorac Vasc Anesth 10:634–637, 1996.)

Kulvatunyou et al ⁶² reviewed a collection of cases of injury to the right subclavian artery during attempted right IJV cannulation. The right subclavian artery is in close proximity when the right IJV is approached low in the neck. Because of interference from the clavicle, puncture of the subclavian artery may not be seen with ultrasound but will be detected by pressure waveform monitoring. The authors have seen several instances of presumed subclavian artery puncture during attempted IJV cannulation low in the neck, in which ultrasound guidance was used, but the needle tip was not visualized in the vein and arterial puncture was detected with pressure waveform monitoring.

The left IJV approach may be particularly hazardous because the innominate (brachiocephalic) vein crosses the IJV at a right angle. A device inserted into the left IJV could perforate the innominate vein, and anecdotal reports verify that this is indeed the case. The right IJV should be preferred to the left IJV primarily for this reason. If the left IJV is used, special care should be exercised not to advance the dilator of a PAC introducer beyond the IJV. The authors prefer to use a shorter-than-normal introducer sheath in this situation (Figure 39-9). Another potential problem with the left-sided approach is injury to the thoracic duct, which terminates variably in the left IJV, the left subclavian vein, or the left innominate vein. The duct may be perforated in the process of placing a CVC, or rarely, the duct may actually be cannulated. Chylothorax and chylopericardium may result, and infusion of fluids into the thoracic duct may produce cardiac tamponade or constrictive pericarditis by retrograde flow into the pericardial lymphatics.⁶³

Figure 39-9 A “standard” pulmonary artery catheter introducer sheath (top) is compared with a shorter sheath (bottom). The authors prefer the shorter sheath for the left internal jugular vein (IJV) approach with the intention to avoid having to push the longer sheath past the right angle junction between the left IJV and the innominate (brachiocephalic) vein. Perforation of the innominate vein is a potentially fatal complication of left IJV cannulation.

The use of fluoroscopy is an important consideration in avoiding injuries to intrathoracic veins. Fluoroscopy allows visualization of the guidewire and the intravascular device as it passes over the guidewire in real time. Fluoroscopy is used routinely by interventional radiologists, cardiologists, and surgeons (the latter when placing surgically implanted central catheters). Fluoroscopy is not often used in anesthesia, emergency medicine, or critical care medicine, but perhaps it should be. In the authors’ opinion, anesthesiologists wanting to place CVCs in the safest possible manner should strongly consider the use of fluoroscopy, especially when there is difficulty passing wires or catheters into the central circulation. However, availability of fluoroscopy equipment and radiology technical support are significant obstacles to using fluoroscopy for most anesthesiologists. It should be noted that TEE is an alternative method for confirming the presence of a wire in the SVC or right atrium before inserting a catheter.

Treatment of Inadvertent Cannulation of Arteries

Although prevention of inadvertent arterial cannulation with large-bore CVCs is paramount, an approach to treating inadvertent arterial cannulation may be needed in rare circumstances. There have been no guidelines in the literature for the treatment of accidental cannulation of arteries with large-bore catheters, but two recently published case series documented better outcomes with surgical or endovascular intervention when compared with removal and compression (“pull/pressure”).^64,⁶⁵ Guilbert et al⁶⁵ published a proposed algorithm for dealing with inadvertent arterial cannulation based on cases from their institutions and review of the literature. They found that the “pull/pressure” method was associated with a large incidence of serious complications (47%), including death, whereas the surgical or endovascular approach was not (Figure 39-10). Based on this, they suggested the algorithm shown in Figure 39-11. Interestingly, a survey of vascular surgeons presented with a hypothetical case of an 8.5-French catheter in a carotid artery found that the respondents saw this complication one to five times per year, and two thirds would simply pull the catheter and apply pressure. However, when vascular surgeons were shown the data from the study by Guilbert et al⁶⁵ at a meeting, most of them changed their management to the surgical or endovascular approach as judged by pretest and post-test questions. Several of the specific findings of Guilbert et al’s⁶⁵ study are worth noting:

1. Arterial cannulation can occur despite the use of ultrasound guidance.

2. The low IJV approach can injure the subclavian or innominate veins, or even the aorta. Arterial injury below the sternoclavicular joint cannot be repaired through a cervical approach. Clinical suspicion of an intrathoracic injury should prompt imaging to locate the site of injury and plan surgical or endovascular treatment.

3. Prolonged arterial cannulation can result in thrombus formation and stroke.

4. A normal carotid duplex examination after removal of a catheter from the carotid artery does not rule out the possibility of a stroke. Because of this, postponing elective surgery has been recommended to avoid unrecognized stroke in an anesthetized patient.

5. False aneurysms or arteriovenous fistulas can occur late after the pull/pressure technique, so close follow-up is needed.

Figure 39-10 Complications from the “pull/pressure” technique of removing a large-bore cannula in an artery were significantly greater than surgical removal with direct repair of the artery or endovascular repair.

(From Guilbert M-C, Elkouri S, Bracco D et al: Arterial trauma during central venous catheter insertion: Case series, review and proposed algorithm. J Vasc Surg 48:918–985, 2008.)

Figure 39-11 A proposed algorithm for management of inadvertent cannulation of a cervical or thoracic artery with a large-bore catheter during attempted central venous catheter placement.

(From Guilbert M-C, Elkouri S, Bracco D, et al: Arterial trauma during central venous catheter insertion: Case series, review and proposed algorithm. J Vasc Surg 48:918–985, 2008.)

Preventing Infections Related to Central Catheters

Catheter-related bloodstream infections occur 0.5 to 4.8 times per 1000 catheter days, have an attributable mortality rate of 0% to 11%, cause an excess hospital stay of 9 to 12 days per episode, and are expensive for the health care system.⁶⁶^–⁶⁸ Infections from central catheters and PACs are related to the time that the catheter is in place and increase significantly after 3 days.^69,⁷⁰ Because many CVCs placed by anesthesiologists for intraoperative monitoring are removed soon after surgery, the risk for infection is reduced. Nevertheless, anesthesiologists should use the evidence-based methods for preventing CVC infections.⁷¹ Implementation of a CVC insertion “care bundle” can significantly reduce infection rates. The bundle of interventions used in Pronovost et al’s⁷² study included appropriate hand hygiene, use of chlorhexidine for skin antisepsis, use of maximal sterile barrier precautions (mask, sterile gown, sterile gloves, and large sterile drapes) during catheter insertion, avoidance of the femoral vein, if possible, and prompt removal of unnecessary catheters. There is substantial evidence that chlorhexidine is a more effective skin cleaning solution than povidone-iodine. Antibiotic ointments applied to the skin puncture site do not affect the risk for bloodstream infection and may actually increase the rate of colonization by fungi and promote antibiotic-resistant bacteria. Recent data suggest that the use of a chlorhexidine-impregnated sponge dressing at the line insertion site may reduce the rate of catheter-related infections.⁷³ The use of antimicrobial-impregnated catheters reduces the incidence of bloodstream infections related to CVCs, and their use should be considered.⁷⁴^–⁷⁶ As noted earlier, antimicrobial-impregnated catheters are recommended in the AHRQ report on evidence-based safety measures. However, these catheters are more expensive and may not be cost-effective when the catheters are going to be removed soon after surgery. For catheters that are intended to remain in place or for high-risk patients (e.g., immunosuppression), antibiotic-impregnated catheters may be worthwhile.⁷⁶

Preventing intraoperative awareness

Three large, prospective, multicenter studies of intraoperative awareness have reported similar overall rates of intraoperative awareness of around 0.1% to 0.2% (Box 39-2).⁷⁷^–⁷⁹ A recent report from China found a larger incidence rate of about 0.4% in that country.⁸⁰ An analysis of cases of awareness during anesthesia from the ASA Closed Claims Project was reported in 1999.⁸¹ Undergoing cardiac surgery increases the risk for intraoperative awareness from the overall level of around 0.1% to 0.2%^78,⁷⁹ to around 0.4% to 1%,^79,⁸²^–⁸⁶ an increased risk of up to 10-fold. Ghoneim et al⁸⁷ recently conducted a review of awareness cases in the literature and confirmed that cardiac surgery is associated with an increased risk. Intraoperative awareness may be a minor or a major complication depending on the severity of the episode of awareness and the response of the individual patient. Intraoperative awareness may result in a significant psychiatric condition such as post-traumatic stress disorder.⁸⁸