ISSN NUMBER: 1938-7172
Issue 7.3 VOLUME 7 | NUMBER 3

Editor:
Michael A. Fiedler, PhD, CRNA

Contributing Editors:
Penelope S Benedik, PhD, CRNA, RRT
Mary A Golinski, PhD, CRNA
Gerard Hogan Jr., DNSc, CRNA
Alfred E Lupien, PhD, CRNA, FAAN
Lisa Osborne, PhD, CRNA
Dennis Spence, PhD, CRNA
Cassy Taylor, DNP, DMP, CRNA
Steven R Wooden, DNP, CRNA

Assistant Editor
Jessica Floyd, BS

A Publication of Lifelong Learning, LLC © Copyright 2013

New health information becomes available constantly. While we strive to provide accurate information, factual and typographical errors may occur. The authors, editors, publisher, and Lifelong Learning, LLC is/are not responsible for any errors or omissions in the information presented. We endeavor to provide accurate information helpful in your clinical practice. Remember, though, that there is a lot of information out there and we are only presenting some of it here. Also, the comments of contributors represent their personal views, colored by their knowledge, understanding, experience, and judgment which may differ from yours. Their comments are written without knowing details of the clinical situation in which you may apply the information. In the end, your clinical decisions should be based upon your best judgment for each specific patient situation. We do not accept responsibility for clinical decisions or outcomes.

Table of Contents


Airway
The supine-to-prone position change induces modification of endotracheal tube cuff pressure accompanied
 by tube displacement

J Clin Anesth 2013;25:2831

Minonishi T, Kinoshita H, Hirayama M, Kawahito S, Azma T, Hatakeyama N


Abstract

Purpose The purpose of this study was to define endotracheal tube (ETT) movement and changes in ETT cuff pressure associated with a position change from supine to prone.

 

Background Repositioning the head and neck after endotracheal intubation can produce significant movement of the ETT tip within the trachea. Flexion and extension of the neck advance and withdraw the ETT within the trachea. The effects of neck rotation (e.g. chin moved right to left) are less well understood. How the ETT may move following neck flexion or extension combined with rotation, such as occurs during a change in position from supine to prone, is unknown. ETT cuff pressure may also change as the position of the cuff changes in the trachea. Increases or decreases in cuff pressure are associated with anesthetic problems such as pressure necrosis of the trachea, leaks during positive pressure ventilation, and pulmonary aspiration.

 

Methodology This prospective, observational study included 132 ASA physical status I - III patients undergoing lumbar spine surgery. Patients with limited neck movement were excluded. Following induction of general anesthesia, ETTs were inserted to a depth of 21 cm in women and 23 cm in men (measured to upper incisors) and secured in the center of the mouth. The ETT cuff was inflated until no leak occurred during 25 cm H2O airway pressure, never more than 30 cm H2O. The distance from the ETT tip to the carina was measured with a fiberoptic bronchoscope after intubation and again after each patient was positioned prone with the head turned to the right.

 

Result ETT movement in the trachea was measurable in 92% of patients after changing from the supine to prone position. In 48% of these patients, the ETT tip moved more than 1 cm. Most often, the ETT withdrew when patients were turned prone. The average ETT movement was 1.25 cm ± 1.1 cm. Changes in ETT cuff pressure were measurable in 86% of patients. Most often, cuff pressure decreased after moving to the prone position. The average cuff pressure decreased by 5 cm H2O ±27 cm H2O. 

 

Conclusion In 92% of patients a change in position from supine to prone was associated with ETT movement within the trachea. The ETT cuff usually moved towards the cords. A change in cuff pressure, usually a decrease in cuff pressure, occurred almost as often.

 

Comment

This study reinforces the adage, “whenever the position of the head and neck changes assume the position of the ETT has changed.” I’ve always taught my students to recheck breath sounds and ETT positioning after turning a patient prone, but I’ll confess I hadn’t thought of checking cuff pressure as well. The fact that cuff pressure was often lower after turning prone is an interesting finding. While average changes in cuff pressure after turning prone were relatively small (5 cm H2O), the variability in the change in cuff pressure (± 27 cm H2O) means many patients will have ETT cuffs that are grossly over or underinflated after turning prone. Cuff pressures should be rechecked as well.

 

An experienced anesthesia provider is likely to place the tip of the ETT midway down the trachea. The adult trachea is about 11 cm long. In an adult, a 1 cm to 2 cm movement of the ETT after turning prone is unlikely to result in extubation or endobronchial intubation when the ETT was optimally placed. But we can increase the margin of safety for our patients by rechecking ETT position every time after we turn out patients prone. Not every ETT is optimally placed, not every patient has an average length trachea, and sometimes the ETT moves more than the book says it does  …  and we all know, there are some patients who haven’t read the book.

Michael A. Fiedler, PhD, CRNA


© Copyright 2013 Anesthesia Abstracts · Volume 7 Number 3, March 30, 2013




Equipment & Technology
An ipsilateral comparison of acceleromyography and electromyography during recovery from nondepolarizing neuromuscular block under general anesthesia in humans

Anesth Analg 2013;117:373-379

Liang SS, Stewart PA, Phillips S


Abstract

Purpose The purpose of this study was to evaluate the accuracy and precision of Train-of-4 (TOF) ratio measurements with an acceleromyograph (AMG) at the adductor pollicis.

 

Background Residual neuromuscular block is present in 40% of PACU patients who have received nondepolarizing neuromuscular block during anesthesia. Residual block increases the risk of respiratory complications and prolonged PACU stays. Clinical signs of residual paralysis may not reliably identify patients with significant degrees of residual block. Some have recommended quantitative neuromuscular block monitoring to verify a Train-of-4 (TOF) ratio greater than 0.9 before extubation.

 

There are three types of quantitative blockade monitors: mechanomyographs (MMG), eletromyographs (EMG), and acceleromyographs (AMG). MMGs measure mechanical movement in response to a TOF and represent the gold standard in monitoring neuromuscular block but are impractical for routine clinical use. EMGs measure the electrical activity in muscles stimulated by a TOF and AMGs measure the force produced by a muscle stimulated by a TOF. Both EMGs and AMGs are clinically feasible for routine monitoring, though a bit more work than a peripheral nerve stimulator. Studies of residual block using an AMG have shown a reduction in residual block with routine AMG use, but 5% of patients still had residual block.

 

Methodology This prospective, observational study included adult patients expected to receive nondepolarizing neuromuscular block during surgery. Patients with neuromuscular disease were excluded. EMG neuromuscular monitoring has been documented as accurate. AMG results were compared with EMG results to determine the accuracy and precision of EMG monitoring. Both AMG and EMG neuromuscular monitoring were measured in the same hand to avoid differences in monitoring conditions between arms. Supramaximal TOF stimulation was delivered every 20 seconds (2 Hz, 200 µsec pulse width). Arms were covered with a force-air warming blanket and hand temperature was monitored.

 

Result A total of 259 pairs of AMG and EMG data were compared from 26 patients. There were over three times as many female participants as male participants. Average body mass index was 26 kg/m2. Rocuronium was used in 19 patients and vecuronium in 7 patients. The acceleromyograph (AMG) was significantly less precise* than the eletromyograph (EMG). The AMG was least precise when the TOF ratio was between 0.4 and 0.79. The AMG was also less accurate* than the EMG. The AMG consistently overestimated the TOF ratio. The TOF ratio displayed by the AMG was consistently higher (indicating greater recovery of neuromuscular block) than the EMG. The overall bias was 0.176 higher on the AMG, but the AMG was up to 0.223 higher at times (out of a maximum possible value of 1.0). This means that overall, when the real TOF ratio was only 0.75 the AMG would report about 0.93, making it appear that someone with significant residual neuromuscular block remaining was almost fully recovered. 

 

Conclusion Acceleromyography is less accurate and less precise than is EMG. When using an acceleromyograph (AMG) to monitor residual neuromuscular block, at least 0.15 should be subtracted from the displayed value to estimate the actual TOF ratio value. When the AMG shows a TOF ratio of > 0.9 the patient may still have significant residual neuromuscular block.

 

Comment

The availability of quantitative neuromuscular blockade monitors has renewed the discussion of residual neuromuscular block … which is a good thing. Acceleromyography is relatively new (in terms of clinically useful devices). It monitors neuromuscular function by detecting the force produced by a muscle during contraction. Some are now calling for acceleromyographs to be used to monitor every patient who has received nondepolarizing neuromuscular blockers. I see two problems with this recommendation. First, as this study points out, acceleromyographs may not be all that accurate. If they consistently tell us patients are less paralyzed than they really are, they could do more harm than good. Second, each study I’ve read so has failed to compare these new quantitative monitors against the best practices currently known to us to insure patients are recovered from neuromuscular block. Are there really that many clinicians who simply reverse patients at the end of the case without checking their recovery from paralysis? Are there that many clinicians who try to visually compare the height of the first and fourth twitches in a Train-of-4? (Oh, I hope not.) I’m certainly in favor of (accurate) quantitative monitors of neuromuscular block. But it seems to me the first steps include minimizing the use of nondepolarizers except for intubation; monitoring TOF during the case so we don’t give more nondepolarizer than needed; and verifying recovery of normal neuromuscular function before extubation with a sustained 5 second head lift, 5 second 100 Hz tetanus, and all other clinical observations we can make. Even using all best practices, residual block may be present in more patients than we might expect. Assessing PACU patients periodically with reliable quantitative blockade monitors to determine the incidence and severity of residual block is an important first step in developing a plan to insure that none of our patients are at risk for the complications associated with residual paralysis.

Michael A. Fiedler, PhD, CRNA


*Notes

Accuracy = closeness to the real, true, actual value.

Precision = reproducibility of the result, that is, little change in the measured value when a thing is measured multiple times.


© Copyright 2013 Anesthesia Abstracts · Volume 7 Number 3, March 30, 2013




General
Balanced crystalloid compared with balanced colloid solution using a goal-directed haemodynamic algorithm

Br J Anaesth 2013;110:231-240

Feldhesier A, Pavlova V, Bonomo T, Jones A, Fotopoulou C, et al


Abstract

Purpose The purpose of this study was to compare perioperative hemodynamics and renal function following goal directed administration of crystalloid versus colloid IV fluids during surgery for primary ovarian cancer.

 

Background Numerous clinical trials have demonstrated that hemodynamic management during surgery has a large impact on outcomes of care. Much work has been done with restrictive fluid protocols and avoiding positive fluid balances. Goal directed fluid management used during high acuity abdominal and/or general surgery is gaining wide acceptance. However, the evidence supporting perioperative fluid restrictions is not conclusive. Neither is there agreement upon which type of solution to use. Furthermore, there is some information that balanced starch colloid solutions may precipitate renal damage in certain clinical scenarios. Typically, goal directed fluid therapy is aimed at:

  1. fluid administration to optimize stroke volume
  2. avoiding low cardiac output states during fluid optimization
  3. optimizing perfusion pressure with vasopressors and inotropes

 

Methodology This pilot study was carried out as a randomized, double blinded, parallel- group trial. Adult females scheduled for laparotomy for cytoreductive surgery due to primary ovarian cancer were included in the study. Women were stratified by whether or not they had ascites preoperatively. Patients were randomly assigned to crystalloid or colloid IV fluids according to a specified hemodynamic algorithm. Arterial and central venous catheters were placed in all subjects as well as an esophageal Doppler. These monitors provided the information needed to follow the fluid administration algorithm. Study fluids were started intraoperatively following the induction of anesthesia. Either crystalloid or colloid IV fluid was administered according to the study protocol and based upon current hemodynamics. All patients received an initial intravenous bolus of 200 mL of fluid. Next, stroke volume was measured. Based upon the stroke volume one of the following actions was taken:

  • stroke volume increased < 10%, fluid administration stopped
  • stroke volume increased >10%, another 200 mL bolus of the same fluid was administered. This process was repeated until there was no further increase in stroke volume >10%
  • stroke volume decreased > 10%, another 200 mL bolus of study fluid was administered

 

If critical instability or hemorrhage occurred, the bolus fluid volume was doubled to 400 mL. If a total of 50 mL/kg of the study fluid was reached, the algorithm allowed for transfusion of FFP. If stroke volume could not be raised by the study fluid or MAP decreased below 70 mm Hg either norepinephriner or an inotrope was administered. The algorithm was followed until the end of surgery. Measurements were performed before and after each administration of study fluid, after every change of MAP or HR, or at least every 15 minutes.

The primary study endpoint was the amount of study fluid used.

Secondary study endpoints were:

  1. dose and duration of use of vasopressors or inotropes
  2. length of ICU stay
  3. length of hospital stay
  4. postoperative organ dysfunction
  5. other complications
  6. perioperative urine output
  7. renal plasma markers creatinine and neutrophil gelatinase-associated lipocalin

 

Results Demographic data were similar between the two groups. Statistical significance was achieved for the following (p < 0.05):

Primary study endpoint:

  • The volume of crystalloid administered was greater than the total volume of colloid administered

 

Secondary endpoints:

  • Higher percentage of patients in crystalloid group reached maximum allowed volume
  • Higher percentage of patients in crystalloid group required FFP
  • Higher stroke volume in colloid group
  • Colloid provided greater cardiac output and lower systemic vascular resistance

Statistical significance was not obtained in any of the other outcome variables measured comparing crystalloid use and colloid use.

 

Conclusion In this pilot study, the balanced Hespan (colloid) group required less total fluid during surgery for ovarian cancer compared to crystalloid. Additionally, colloid was associated with better hemodynamic stability, a higher stroke volume and cardiac index, and lower systemic vascular resistance. Hespan provided an overall beneficial intravascular effect and was associated with less requirement for plasma compared to crystalloid. Perioperative renal function was the same between groups.

 

Comment

Fluid management, specifically during complex surgical cases, should be based on the best available evidence suggesting favorable outcomes and not simply because it is considered “routine clinical care.” Assertions and opinions should not overpower evidence based decision making as these can precipitate acute morbidity and even mortality. In the past, comparatively few clinical trials pertaining to intraoperative fluid management existed. The good news is many new trials are emerging like this one, adding to the body of evidence upon which we can base our care. Historically, established guidelines and formulas existed regarding how much volume to give BUT these guidelines were NOT based on solid evidence. We all know the equations that tell us how many mL/kg of IV fluid to give and how to replace NPO deficits. But we now know much more about what happens physiologically to the body during surgical procedures. Consider the following: surgery induces antidiuresis. Oliguria is mediated by vasopressin, catecholamines, and activation of the renin angiotensin aldosterone axis. Retention of water and sodium occurs and there is a decreased ability to concentrate the urine. Cell membrane permeability is altered and global inflammatory processes can cause end organ dysfunction. For complex surgeries, evidence supports an individualized approach to fluid therapy often involving cardiovascular monitoring (e.g. stroke volume variation). This study provides us with additional evidence supporting goal directed approaches using current modalities and individualization of care.

Mary A Golinski, PhD, CRNA


Hespan used:  HES, 130/0.4, 6%


© Copyright 2013 Anesthesia Abstracts · Volume 7 Number 3, March 30, 2013





Postoperative residual neuromuscular blockade is associated with impaired clinical recovery

Anesth Analg 2013;117:133-141

Murphy GS, Szokol JW, Avram MJ, Greenberg SB, Shear T, Vender JS, Gray J, Landry E


Abstract

Purpose The purpose of this study was to define the incidence and severity of skeletal muscle weakness in patients with residual neuromuscular block. A secondary aim was to identify the most common signs and symptoms associated with residual block. Residual block was defined as a Train-of-4 (TOF) ratio less than 0.9 measured by acceleromyography.

 

Background Residual neuromuscular block is common early in the postoperative period. About 40% of patients who have received intermediate-acting nondepolarizing neuromuscular blockers during general anesthesia arrive in the PACU with a Train-of-4 (TOF) ratio less than 0.9. A TOF ratio < 0.9 is associated with complications ranging from patient discomfort to severe injury; especially those involving respiration and the airway. A TOF ratio < 0.9 has been associated with:

  1. feeling “weak”
  2. double vision
  3. difficulty speaking
  4. prolongation of PACU stay
  5. hypoxia

The PACU Aldrete score, commonly used to determine readiness for discharge, does not address residual neuromuscular blockade or skeletal muscle weakness directly.

 

Awake volunteers reported subjective “fatigue” during a mivacurium infusion when the TOF ratio decreased to between 0.85 and 0.9. Residual neuromuscular block is not the only potential cause of skeletal muscle weakness during the early postoperative period. It may also be the result of potent inhalation agents, hypothermia, electrolyte abnormalities, and other less common causes. It is likely to be multifactorial.

 

Methodology This was a planned secondary analysis of data from a previous study of residual neuromuscular block. It included ASA I and II patients who underwent elective surgery expected to last at least 60 minutes. Patients were randomly assigned to an acceleromyography group or a control group using a traditional peripheral nerve stimulator for monitoring. The general anesthetic was standardized for both groups; propofol, sevoflurane, and fentanyl in prescribed dose ranges. Rocuronium 0.6 mg/kg to 0.8 mg/kg was used for intubation followed by 5 mg to 10 mg doses during the case to maintain a TOF of 2 to 3 twitches. Neuromuscular block was antagonized with 0.05 mg/kg neostigmine at the end of the case in both groups.

 

A TOF-Watch SX was used to monitor neuromuscular block in all patients of both groups. In the acceleromyography group the quantitative TOF ratio value was visible at all times during the case. In the acceleromyography group the TOF ratio could be used to decide how much additional rocuronium to administer during the final 45 to 60 minutes of the case. In the control group, the quantitative TOF ratio display was covered and not visible to the anesthetist. In the control group, the TOF-Watch SX was used only to generate a Train-of-4 and the twitches assessed qualitative for fade in twitch height.

 

In both groups, a 5 second head lift or hand grip, ability to follow commands, and regular spontaneous ventilation were required before extubation. In the acceleromyography group, a quantitative TOF ratio of >0.8 was also required. In the control group, the TOF ratio was visually estimated by observing hand twitches.

 

Upon arrival in the PACU, a quantitative TOF ratio was measured with the TOF-Watch SX on all patients in both groups (TOF-Watch SX had not been calibrated beforehand). Objective “signs” and patient reported “symptoms” of skeletal muscle weakness were assessed upon PACU arrival and at 20 min., 40 min., and 60 min. while in the PACU. The PACU Aldrete score was assessed every 10 minutes. Staff and data collectors were blinded to the patient’s group assignment.

 

Result Data from 149 patients were analyzed. Of these patients, 49 had TOF ratios less than 0.9 (TOF < 0.9 group) and 101 had TOF ratios greater than or equal to 0.9 (TOF > 0.9 group) on PACU arrival. Demographics between these groups were similar except that hypertension was present almost twice as often in the TOF < 0.9 group. Specifically, there was no difference in core body temperature between groups at the end of the case. The average total dose of rocuronium given during the case did not differ between groups, but 25% of patients with a TOF < 0.9 at PACU arrival had received rocuronium during the last 45 minutes of the case while only 7% of patients with a TOF > 0.9 had received rocuronium during the last 45 minutes.

 

Patients with a TOF < 0.9 at PACU arrival also had fewer twitches in the Train-of-4 when neostigmine was administered (3 twitches) compared to TOF > 0.9 patients (4 twitches)(P<0.0001). In the TOF < 0.9 group, the median TOF ratio was 0.75 but TOF ratio values were as low as 0.33, indicating significant paralysis in some patients. On PACU arrival most patients had subjective symptoms of skeletal muscle weakness no matter which group they were in. Objective signs of skeletal muscle weakness were present at PACU arrival in 43% of TOF < 0.9 patients but only 6% of TOF > 0.9 patients (P < 0.0001). The incidence of objective signs of weakness decreased the longer patients were in the PACU. No objective signs of weakness were observed in the TOF > 0.9 group at 20 min., 40 min., or 60 min. after PACU admission. The most common objective signs of weakness on PACU arrival were:

  1. inability to hold eyes open for 5 seconds - 89% TOF < 0.9 vs. 36% TOF > 0.9
  2. inability to sustain 5 second head lift - 74% TOF < 0.9 vs. 15% TOF > 0.9
  3. inability to cough - 50% TOF < 0.9 vs. 12% TOF > 0.9
  4. inability to swallow - 37% TOF < 0.9 vs. 7% TOF > 0.9
  5. inability to sustain 5 second hand grip - 33% TOF < 0.9 vs. 6% TOF > 0.9

There was no difference in the time until PACU discharge between the TOF < 0.9 and TOF > 0.9 groups.

 

Conclusion PACU patients with a TOF ratio < 0.9 had a higher incidence and severity of residual skeletal muscle weakness after intermediate-acting nondepolarizing muscle relaxation.

 

Comment

Acceleromyography is the monitoring of neuromuscular function with a device that detects the force produced by a muscle during contraction. The availability of clinically feasible acceleromyography with devices such as the TOF-Watch SX has stimulated renewed interest in residual neuromuscular block. While fairly expensive, acceleromyographs can be much more accurate than other methods of monitoring neuromuscular blockade. Some would suggest that we should monitor neuromuscular block in every patient with these devices. I’m not convinced of that yet. What is pretty certain is that more patients than we realize show up in the PACU with more residual paralysis than we think they do and this residual paralysis is associated with patient morbidity. Fortunately, a number of recent studies have examined the incidence and effects of residual neuromuscular block. Unfortunately, each one that I’ve read so far, including this one, is a mix of good research and bad. Here is what I think we can learn from the good in this study.

 

Monitoring of neuromuscular block was probably not as rigorous in the control group (using a peripheral nerve stimulator) as we’d like. For example, all patients were ostensibly checked for a 5 second sustained head lift before extubation and transport to the PACU. Yet, on arrival in the PACU, 33% of patients couldn’t sustain a head lift … so they weren’t really ready for extubation. The study rightly points out that patients who were monitored with acceleromyography arrived with fewer objective signs of residual neuromuscular block and that these signs went away more quickly than patients monitored with the traditional peripheral nerve stimulator. But the acceleromyography patients also had a visual estimation of their Train-of-4 ratio (which simply doesn’t work), were more likely to have received rocuronium during the last hour of the case, and had fewer twitches in the Train-of-4 when neostigmine was given. In all patients the dose of neostigmine (0.05 mg/kg) was not maximized (0.07 mg/kg) which may have contributed to residual block.

 

Every anesthesia group should get some of these new acceleromyographs and find out how common residual neuromuscular block is in their patients. Then steps should be taken to eliminate residual block and the complications that go with it. Production pressure motivates us to emerge patients as quickly as possible and get them to the PACU. But we may need to renew our conservatism when deciding when to pull the tube. In all patients, limiting the dose of nondepolarizer administered in the last hour of the case, maximizing the number of twitches before we give neostigmine, always using a test of neuromuscular recovery (e.g. 5 second sustained tetanus or head lift), and administering a maximum dose of neostigmine (0.07 mg/kg up to 5 mg) will reduce the incidence and severity of residual neuromuscular block. We may not need a better tool to monitor neuromuscular block as much as we need to better use our current tools and techniques.

Michael A. Fiedler, PhD, CRNA


© Copyright 2013 Anesthesia Abstracts · Volume 7 Number 3, March 30, 2013





Simulation-based trial of surgical-crisis checklists

N Engl J Med 2013;368:246-53

Arriaga AF, Bader AM, Wong J, Lipsitz SR, Berry WR, Ziewacz JE, Hepner DL, Boorman DJ, Pozner CN, Smink DS, Gawande AA


Abstract

Purpose The purpose of this study was to determine if the use of crisis surgical checklists would improve adherence with life-saving processes during simulated emergencies.

 

Background Operating room crises, such as massive hemorrhage and cardiac arrest, are highly stressful, high-risk events that require rapid action by the surgical team. Estimates suggest that for every 10,000 surgical cases performed at least 145 such events occur annually. Failure to effectively manage crises and communicate on actions needed during surgical emergencies may contribute to morbidity and mortality. Checklists have been used successfully to aid performance during rare and unpredictable events in the aviation and nuclear power industry for years. In medicine, the World Health Organization Surgical Checklist has been found to reduce morbidity and mortality. Unfortunately, crisis-related checklists have been largely untested in a systematic fashion among staff providers in a simulated environment. The investigators in this study hypothesized that the use of checklists during a series of simulated crises would significantly improve team adherence to life-saving procedures of care.

 

Methodology This was a randomized controlled trial involving 17 mock surgical teams from community and academic medical centers in the Boston area. Surgical teams consisted of an attending physician anesthesiologists, anesthesia and surgical residents, CRNAs, operating room nurses, surgical technicians, and a mock surgeon. Each team was exposed to a series of simulated intraoperative crises such as air embolism, anaphylaxis, asystolic cardiac arrest, hemorrhage followed by ventricular fibrillation, malignant hyperthermia, unexplained hypotension, hypoxemia followed by unstable bradycardia, and unstable tachycardia. Each team was randomly assigned to manage half the scenarios with checklists and the other half without checklists. Statistical analyses were appropriate. A P < 0.05 was significant.

 

Result There were 67 participants divided into 17 operating-room teams who completed 106 simulated surgical crisis scenarios (Operating Room nurse = 30%, Anesthesiologists = 25%, Anesthesia Resident = 15%, Surgical technologist = 13%, CRNA = 10%, Surgical Resident = 3%, Attending surgeon = 3%). Checklist use during a simulated crisis resulted in an almost 4-fold reduction in the failure to adhere to critical procedural steps in operating-room crisis management (6% failure rate vs. 23%, P < 0.001; Figure 1). During ACLS scenarios, participants who used a checklists missed 7% of steps vs. 17% missed steps without a checklists (P = 0.005). If the ACLS scenario was preceded by a hemodynamically unstable condition, 9% of steps were missed when a checklist was used compared to 27% missed steps without a checklist (P < 0.001). During malignant hyperthermia; anaphylaxis; hemorrhage; and air embolism scenarios, use of a checklist resulted in 3% missed steps compared to 24% missed steps without a checklist (P = 0.002).

 

 

Figure 1. Checklist Use and Missed Critical Steps

Figure 1

 

Conclusion In a simulated environment, the use of surgical crisis checklists improved the management of operating room crises. Results suggest the use of these checklists may help improve outcomes during a crisis.

 

Comment

This was another study published by Dr. Gawande and colleagues that demonstrated that the use of simple checklists can improve adherence to critical steps (author of The Checklist Manifesto: How to Get Things Right). In previous research studies his group demonstrated that the found that use of the World Health Organization 19-item surgical checklist was associated with over a one-third reduction in complications in patients undergoing urgent, non-cardiac surgery, in diverse hospitals around the world (see Anesthesia Abstracts September, 2010).1 I think the results of this current study add to the body of knowledge demonstrating checklists can improve adherence to critical steps.

 

So how can you apply these results? First, I think the checklists developed in this study should be used during team training in a high fidelity simulator. Dr Gawande’s group recommends developing a multidisciplinary implementation team to adapt the checklists at your institution (http://www.projectcheck.org/crisis.html). They recommend placing the checklists in an easy to find, readily accessible location, such as on the side of the anesthesia machine, cart, or near the OR nurse. Institutions should train surgical teams on the purpose of the checklists so they become comfortable with using them. This is especially important because in an emergency it is sometimes easy to forget to “grab the checklist” if you are not used to doing this. When using the checklist during an emergency, Dr Gawande’s group recommends the person reading the checklist should be someone that is not involved in direct patient care. Finally, it is extremely important to create an implementation plan to diffuse this innovation. (I recommend reading up on Diffusion of Innovation Theory). Leaders and educators in simulation should consider integrating crisis resource management training with checklist training. Readers are referred to the Project Check website (http://www.projectcheck.org/crisis.html).

Dennis Spence, PhD, CRNA


1. Weiser TG, Haynes AB, Dziekan G, Berry WR, Lipsitz SR, Gawande AA. Effect of a 19-item surgical safety checklist during urgent operations in a global patient population. Ann Surg 2010;215:976-980.


The views expressed in this article are those of the author and do not reflect official policy or position of the Department of the Navy, the Department of Defense, the Uniformed Services University of the Health Sciences, or the United States Government.


© Copyright 2013 Anesthesia Abstracts · Volume 7 Number 3, March 30, 2013




Regional Anesthesia
Perioperative comparative effectiveness of anesthetic technique in orthopedic patients

Anesthesiology 2013;118:1046-58

Memtsoudis SG, Xuming S, Ya-Lin C, Stundner O, Liu SS, Banerjee S, Mazumdar M, Sharrock MB


Abstract

Purpose The purpose of this study was to determine if neuraxial anesthesia improved perioperative outcomes after major joint arthroplasty.

 

Background Neuraxial anesthesia has been postulated to improve perioperative outcomes after total knee and hip arthroplasty. Some studies have found neuraxial anesthesia was associated with decreased thromboembolic events, reduced intraoperative blood loss, and reduced operating room times. These studies were conducted at single institutions with relatively small sample sizes. This study sought to use a large national sample to examine if neuraxial anesthesia for total knee and hip arthroplasty was associated with improved perioperative outcomes and decreased resource utilization.

 

Methodology This was a retrospective examination of data collected between 2006 and 2010 from the Premier Perspective, Inc. (Charlotte, NC) administrative database. This database includes information on discharges from approximately 4,000 hospitals in the United States. Using ICD-9 Clinical Modification procedure codes, data were collected on patients who underwent primary total knee and total hip arthroplasty. Patients were classified into one of three groups: (1) general anesthesia, (2) general anesthesia plus neuraxial anesthesia, and (3) neuraxial anesthesia only. Investigators examined demographic and complication variables and used multivariate regression analysis to determine if the use of neuraxial anesthesia alone or in combination with general anesthesia improved outcomes. A P < 0.05 was considered significant.

Result A total of 382,236 patient records were examined. Of these, 75% (292,804) were performed under general anesthesia, 14% (49,396) under combined neuraxial plus general anesthesia, and 11% (40,036) under neuraxial anesthesia alone. Anesthetic techniques for total knee arthroplasty were distributed as follows:

  • 76% were performed under general anesthesia
  • 13% under combined neuraxial plus general anesthesia
  • 11% under neuraxial anesthesia

Anesthetic techniques for total hip arthroplasty were distributed as follows:

  • 79% were performed under general anesthesia
  • 12% under combined neuraxial plus general anesthesia
  • 9% under neuraxial anesthesia

The average age of all patients was approximately 67 years, with a majority of patients being female. Differences in demographic data were not clinically significant. Patients in the neuraxial group were slightly older than those in the neuraxial plus general anesthesia and general anesthesia group.

Overall complication rates were generally lower in groups that included neuraxial anesthesia compared to general anesthesia alone (Table 1). The most common complication was the need for blood transfusion. Transfusion rates were significantly higher in the general anesthesia group (P <0.05). Non-myocardial infarction cardiac complications (i.e, arrhythmias) were the next most frequent complication, with rates ranging from 6% to 7% (P = NS). Infections and acute renal failure rates were significantly higher in the general anesthesia and neuraxial plus general anesthesia groups when compared to neuraxial anesthesia alone (P <0.0001). After total knee arthroplasty, patients undergoing general anesthesia had significantly higher pulmonary embolism rates (P = 0.003). The 30-day mortality rates in both groups were significantly higher after general anesthesia (0.18%) compared to neuraxial plus general (0.1%) and neuraxial anesthesia (0.1%) (P <0.05). The incidence of prolonged length of stay was lower after neuraxial (29%) and neuraxial plus general anesthesia (28%) compared to the general anesthesia group (35%, P < 0.001). The incidence of increased cost was significantly higher in the general anesthesia group (23%) compared to the neuraxial plus general (18%) and neuraxial anesthesia groups (21%, P < 0.001).

 

 

Table 1: Comparison of Complications

 

Total Knee

N = 257,243

Total Hip

N = 124,993

Complication

N

N/G

G

P value

N

N/G

G

P value 

Blood transfusion

13.1%

15.2%

16.3%

<0.0001

20.3%

16.4%

23.1%

<0.0001

Cardiac (non-MI)

6.2%

6.6%

6.2%

NS

6.1%

6.6%

6.8%

NS

All infections

2.9%

3.7%

4%

<0.0001

3.6%

4.4%

5.4%

<0.0001

Acute renal failure

1.1%

1.4%

1.6%

<0.0001

1.1%

1.5%

2.1%

<0.0001

Note: N = neuraxial, N/G = neuraxial plus general, G = general anesthesia. PE = pulmonary embolism. CVA = cerebrovascular accident. Pulmonary = pulmonary compromise.

 

After controlling for covariates, general anesthesia was associated with higher odds of resource utilization and systemic complications compared with neuraxial or neuraxial plus general anesthesia after both total knee and hip arthroplasty (Table 2 & 3). For example, when compared to neuraxial anesthesia alone, patients who underwent general anesthesia were 1.8 times more likely to experience pulmonary compromise after total knee arthroplasty (P <0.0001). After total hip arthroplasty they were 3.34 times more likely to experience pulmonary compromise (P <0.0001). After total hip arthroplasty the odds of a cerebrovascular event were 3.15 times more likely after general anesthesia as compared to neuraxial anesthesia (P <0.0001).

 

 

Table 2. Complications after Total Knee Arthroplasty

Total Knee Arthroplasty  N = 257,243

Complication

General vs. Neuraxial

Adjusted Odds ratio

P value

Blood transfusion

1.23

<0.0001

Cardiac (non-MI)

1.09

0.009

All infections

1.38

<0.0001

Acute renal failure

1.44

<0.0001

Pulmonary embolism

1.24

NS

Pulmonary

1.83

<0.0001

Pneumonia

1.38

<0.0001

Acute MI

1.10

NS

Mechanical vent.

1.72

<0.0001

CVA

1.58

NS

30-day mortality

1.83

0.02

Note: Pulmonary = pulmonary compromise. MI = myocardial infarction. CVA = cerebrovascular event. Vent = ventilation. Covariates controlled for included age, gender, race, admission type, hospital size, payor type, hospital location, teaching status, surgical pathology, and comorbidity burden.

 

Table 3. Complications after Total Hip Arthroplasty

Total Hip Arthoplasty  N = 124,993

Complication

General vs. Neuraxial

Adjusted Odds ratio

P value

Blood transfusion

1.14

<0.0001

Cardiac (non-MI)

1.13

0.02

All infections

1.45

<0.0001

Acute renal failure

1.7

<0.0001

Pulmonary embolism

1.26

NS

Pulmonary

3.34

<0.0001

Pneumonia

1.27

0.008

Acute MI

1.10

NS

Mechanical vent.

1.57

0.008

CVA

3.15

<0.0001

30-day mortality

1.28

NS

Note: Pulmonary = pulmonary compromise. MI = myocardial infarction. CVA = cerebrovascular event. Vent = ventilation. Covariates controlled for included age, gender, race, admission type, hospital size, payor type, hospital location, teaching status, surgical pathology, and comorbidity burden.

    

Conclusion Analysis of a large national sample of joint arthroplasty procedures demonstrated that neuraxial anesthesia is superior to general anesthesia in reducing resource utilization and perioperative complications. Many outcomes were also improved after neuraxial plus general anesthesia compared to general anesthesia alone.

 

Comment

Many perioperative complications occur at such low rates that large sample sizes are needed to see differences. Furthermore, randomized controlled trials often have such tight inclusion/exclusion criteria and controls that can make their generalizability difficult. Perioperative comparative effectiveness research attempts to address these concerns by using large databases to compare outcomes in a representative population of patients. This study is one of the largest studies ever-published comparing outcomes after major joint arthroplasty surgery. I believe the results support what many anesthesia providers believe; that neuraxial anesthesia use in this population is associated with not only improved analgesia, but decreased perioperative complications and resource utilization.

 

It was interesting that even in the neuraxial plus general anesthesia group outcomes were still better than general anesthesia alone. The exact reason for this is unknown. Could it be related to a reduced stress response and pain or some other factors? Could it to due to decreased embolic phenomenon, which has been reported after neuraxial anesthesia? What about the effect of continuous peripheral nerve block catheters on outcomes? This study does not allow us to answer these questions.

 

I think there are some important other findings from this study that warrant discussion. Patients undergoing joint arthroplasty are at high risk for nonmyocardial infarction cardiac complications (i.e., arrhythmias). In this study the incidence of these complications after total knee and hip arthroplasty was >6%. This is an important finding I think anesthesia providers should be aware may occur. Additionally, infection rates were approximately 3%-6%, with higher rates associated with general anesthesia either alone or in combination with neuraxial anesthesia. Anesthesia providers should ensure they are giving perioperative antibiotics in a timely fashion prior to skin incision and ensure they are mindful of aseptic technique and other methods to reduce infections.

 

So how can anesthesia providers apply these results to practice? Well, I think there is a clear benefit to using neuraxial anesthesia for major joint surgery. I think anesthesia providers should use these techniques whenever possible, with the caveat they be aware of guidelines for the use of neuraxial anesthesia in patients who may receive anticoagulants or the newer antiplatelet medications. This requires close communication with the surgical team and nursing staff to make sure we are all on the same page.

Dennis Spence, PhD, CRNA


The views expressed in this article are those of the author and do not reflect official policy or position of the Department of the Navy, the Department of Defense, the Uniformed Services University of the Health Sciences, or the United States Government.


© Copyright 2013 Anesthesia Abstracts · Volume 7 Number 3, March 30, 2013