| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Click here to read this article as a CME activity
a Michael E. DeBakey Department of Surgery, Division of Congenital Heart Surgery, Baylor College of Medicine, Houston, Texas
b Division of Congenital Heart Surgery, Texas Children's Hospital, Houston, Texas
c Department of Anesthesiology and Critical Care Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
Accepted for publication February 4, 2008.
* Address correspondence to Dr Morales, Division of Congenital Heart Surgery, Texas Children's Hospital, 6621 Fannin St, MC-WT 19345H, Houston, TX 77030 (Email: dlmorale{at}texaschildrenshospital.org).
Presented at the Forty-third Annual Meeting of The Society of Thoracic Surgeons, San Diego, CA, Jan 29–31, 2007.
| Pediatric cardiac surgery:
The Annals of Thoracic Surgery CME Program is located online at http://cme.ctsnetjournals.org. To take the CME activity related to this article, you must have either an STS member or an individual non-member subscription to the journal.
|
 |
Abstract |
|---|
 Top Abstract IntroductionPatients and MethodsResultsCommentDiscussionReferences |
|---|
Methods: Between October 2002 and June 2006, 112 patients underwent primary Fontan procedures; 38 (34%) were EOR and 74 (66%) were non-EOR. These two cohorts were not different (p < 0.05) in age, weight, surgery time, dominant ventricular morphology, hypoplastic left heart syndrome, prior bidirectional Glenn, concomitant procedures, atrioventricular valve regurgitation, and ventricular function. Analysis of variance was used to compare mean pulmonary artery pressure, mean arterial blood pressure, and mean common atrial pressure as a function of time.
Results: During the first 12 hours postoperatively, mean pulmonary artery pressure and mean common atrial pressure were significantly lower and mean arterial blood pressure was significantly higher in the EOR group than the non-EOR group (p < 0.05). No EOR patient required reintubation. Mean durations of inotropic agents (1.1 versus 2.4 days), chest tubes (5.8 versus 7.2 days), intensive care unit stay (3 versus 4.7 days), and hospital stay (8.6 versus 11.3 days) for EOR patients were shorter than for non-EOR patients (p < 0.05). Intensive care unit and hospital costs for EOR patients were 35% and 31% lower, respectively, than for non-EOR patients (p < 0.05). Kaplan–Meier survival for EOR patients (3 years, 100%) was not different (p = 0.3) than for non-EOR patients (1 and 3 years, 96%).
Conclusions: After the Fontan procedure, selective EOR can be performed safely and improves postoperative hemodynamics, decreases hospital resource utilization, and reduces hospital recovery time.
During the past decade continued modifications in surgical techniques along with improvements in perioperative care have combined to greatly improve morbidity and mortality rates in patients after a Fontan procedure [1, 2]. One such improvement is the well-accepted strategy of timely extubation in Fontan patients to minimize the deleterious effects of positive-pressure ventilation on pulmonary blood flow and hemodynamics [3].
Successful early extubation even in young children after cardiac surgery has been described by several authors [4–6], but the definition of early extubation varies among studies. Extubation in the operating room (EOR) has been less frequently described in this literature. The use of shorter-acting anesthetic drugs, along with certain regional anesthesia techniques, has allowed cardiac anesthesiologists increased flexibility in planning anesthetic regimens that permit appropriate early extubation. Additionally, the education and commitment of the entire perioperative team regarding early extubation and postoperative airway management is a critical component in allowing safe and successful early extubation of pediatric cardiac patients.
As the strategy of timely extubation after Fontan operation was applied at Texas Children's Hospital (TCH), time to extubation became progressively shorter until there were select patients who were being extubated within 30 minutes of arriving to the cardiovascular intensive care unit (ICU). Little advantage was seen in not extubating this select group of patients in the operating room. Therefore, in October of 2002, all patients undergoing a Fontan procedure at TCH began to be evaluated as potential candidates for EOR. Herein, this study examines how EOR has affected outcomes and practice in this Fontan population.
|
Patients and Methods |
|---|
|
TopAbstractIntroductionPatients and MethodsResultsCommentDiscussionReferences |
|---|
Extubation in the Operating Room Strategy
All primary Fontan patients are considered candidates for EOR. At the time of the preanesthesia evaluation, relative contraindications such as findings on the pre-Fontan catheterization (eg, significant arteriovenous malformations, high pulmonary vascular resistance) that make the patient a marginal Fontan candidate or significant respiratory issues (eg, critical airway, cleft palate) are noted. These issues are discussed between the surgeon and anesthesiologist preoperatively, but no patient is excluded from EOR at this time. The anesthesia regimen is tailored to allow flexibility in deciding whether to extubate in the operating room based on the patient's intraoperative course. This strategy includes limiting the use of opioids and, when they are necessary, using shorter-acting opioids such as remifentanil. The anesthesiologist relies more on inhaled anesthetics such as sevoflurane than with most congenital cardiac cases. Inhaled anesthetics are more readily reversed than opiates if the patient is deemed eligible for early extubation in the operating room. For patients less than 25 kg, caudal blocks are given preoperatively as an adjunct to the postoperative pain management regimen in an attempt to limit opioid use. Typically, the caudal anesthesia consisted of a combination of a local anesthetic (1 mL/kg of 0.25% bupivacaine or 1 mL/kg of 0.2% ropivacaine up to a maximum of 20 mL), morphine (75 µg/kg of preservative free morphine), and clonidine (1 µg/kg of clonidine) if it was used.
Once stable off cardiopulmonary bypass, patients are considered for EOR if the following criteria are met: (1) an uneventful intraoperative course (ie, no hemodynamic instability); (2) no evidence of postoperative bleeding; (3) a stable electrocardiogram; (4) no concerning transesophageal echocardiographic findings; and (5) no respiratory issues that have been amplified by airway edema. Ultimately, the decision for EOR was based on the clinical judgment of the surgeon and anesthesiologist together.
Statistical Methods
Student's t test and 
2 tests were used to compare the continuous and nominal variables, respectively, in each group. These tests were adjusted for the variance in group size. Analysis of variance was used to compare mean arterial pressure, mean pulmonary artery pressure, and mean common atrial pressure between the two groups at five postoperative times during the initial 12-hour postoperative period (exiting the operating room [OR] and at 1, 2, 6, and 12 hours after the operation). Analysis of variance was used to test for any variation among the means of all observations in the group. It also considers the difference between each subject and the subject's group mean and the difference between each group and the overall mean.
Inotropic score was calculated using a scoring system described by Wernovsky and others [7] that was modified to incorporate vasopressin. Survival analysis was conducted using the Kaplan–Meier method, and log-rank tests were used to compare survival between the EOR and non-EOR groups. Total hospital costs (direct and indirect) were adjusted for inflation increases with time and were provided by the financial services department at TCH. The level for statistical significance was set at a probability value of less than 0.05. All analyses were conducted with the SAS statistical package (SAS Institute, Inc, Cary, NC).
|
Results |
|---|
|
TopAbstractIntroductionPatients and MethodsResultsCommentDiscussionReferences |
|---|
|
|
|
Anesthesia and Operative Data
Five patients (13%) in the EOR group had a history of reactive airway disease compared with 7 patients (10%) in the non-EOR group (p > 0.05). In the EOR group, there was 1 patient with a history of subglottic stenosis. In the non-EOR group, there was 1 patient with micrognathia, 1 patient with a cleft lip and palate, and 1 patient with a known difficult airway. Caudal blocks were placed in 28 patients (74%) in the EOR group compared with 11 (15%) in the non-EOR group.
The Fontan operation at TCH is performed with aortic and bicaval cannulation. Currently, total cavopulmonary connection is performed by placement of a nonfenestrated 18F to 22F Gore-Tex (W.L. Gore & Assoc, Flagstaff, AZ) extracardiac conduit without arresting the heart. If the heart is being arrested for other procedures, there is more of a tendency to create a lateral tunnel Fontan. Also, fenestrations are performed for most patients with hypoplastic left heart syndrome and those with elevated pulmonary vascular resistance. However, the use of lateral tunnels and fenestrations has significantly decreased during the study period. The EOR group had an extracardiac conduit placed (87%; 33 of 38) more often than the non-EOR group (57%; 2 of 74; p < 0.01). Twenty-nine percent (11 of 38) of the EOR group had a fenestrated Fontan whereas 64% (47 of 74) of patients in the non-EOR group had a fenestration (p < 0.01). Concomitant procedures performed included atrioventricular valve repair (EOR group, 0; non-EOR group, 7 of 74 [9%]), atrial septectomy (EOR group, 4 of 38 [11%]; non-EOR group, 10 of 74 [14%]), pulmonary artery augmentation (EOR group, 4 of 38 [11%]; non-EOR group, 15 of 74 [20%]), and placement of a permanent pacemaker (EOR group, 1 of 38 [3%]; non-EOR group, 4 of 74 [5%]). There was no significant difference (p > 0.05) between the cohorts in regard to these specific concomitant procedures. There was also no difference in the proportion of patients undergoing concomitant procedures in each group (EOR group, 7 of 38 [18%]; non-EOR group, 27 of 74 [36%]; p > 0.05).
Mean cardiopulmonary bypass time and aortic cross-clamp time were significantly longer in the non-EOR group (127.9 ± 41.7 minutes; 50.2 ± 50 minutes) than in the EOR group (102.6 ± 41.5 minutes; 14.4 ± 32 minutes; p < 0.05), and the incidence of aortic cross-clamping was significantly lower in the EOR group (24%, 9 of 38) than the non-EOR group (57%, 42 of 74; p < 0.01). Four patients (11%) in the EOR group had a mean circulatory arrest time of 10 ± 8.7 minutes. and 10 patients (14%) in the non-EOR group had a mean time of 7.9 ± 8.2 minutes; neither the incidence nor duration of circulatory arrest was significantly different between the groups (p = 0.77, p = 0.68). Mean surgical (skin-to-skin) time was also not significantly different between the EOR and non-EOR groups (EOR group, 4 hours 54 minutes ± 1 hour 8 minutes; non-EOR group, 5 hours 25 minutes ± 1 hours 23 minutes; p = 0.15). The mean time from surgical end time (dressing applied, drapes off, and patient washed) to arrival in the ICU was not different between the EOR group (16.2 ± 7.0 minutes) and the non-EOR group (17.2 ± 10.5 minutes; p > 0.05).
No patients in the EOR group required reintubation. The mean inotrope score leaving the OR was not significantly different between the two groups (EOR group, 3.6 ± 2.3; non-EOR group, 4.6 ± 3.2; p = 0.14). Average inotrope scores were significantly lower at 2 hours and 6 hours in the EOR group (3.2 ± 2.6 and 2.9 ± 2.3) compared with the non-EOR group (4.7 ± 3.3 and 5.2 ± 4.5; p < 0.05, p < 0.01, respectively). In the initial 12-hour postoperative period, mean pulmonary arterial pressure and mean common atrial pressure were significantly lower, and mean arterial pressure was significantly higher in the EOR group compared with the non-EOR group (p < 0.05; Fig 2).
|
The length of time on inotropic support was significantly shorter in the EOR group (1.1 ± 0.9 days) than in the non-EOR group (2.4 ± 5 days; p < 0.05). The most commonly used inotropic agents were milrinone (0.375 to 0.5 µg–1 · kg · min–1), epinephrine (0.03 to 0.07 µg–1 · kg · min–1), and dopamine (2.5 to 5 µg–1 · kg · min–1). The duration of chest tube drainage was also shorter for the EOR group (5.8 ± 2.5 days) than for the non-EOR group (7.2 ± 6.2 days; p = 0.05). The EOR group had significantly reduced ICU (EOR, 3 ± 2.9 days; non-EOR, 4.7 ± 6.3 days; p < 0.05) and hospital (EOR, 8.6 ± 1.8 days; non-EOR, 11.3 ± 8.8 days; p = 0.01) length of stay. Average ICU and hospital costs were significantly lower for EOR patients than for non-EOR patients (p < 0.05). In fact, ICU and hospital costs for EOR patients were 35% and 31% lower than for non-EOR patients (Fig 3).
|
|
Comment |
|---|
|
TopAbstractIntroductionPatients and MethodsResultsCommentDiscussionReferences |
|---|
The negative effects of positive-pressure ventilation on the passive pulmonary blood flow of Fontan circulations are well described [3]. Therefore, the postoperative strategy of early extubation in Fontan patients to minimize these detrimental effects is logical and well accepted [11]. As the postoperative course of Fontan patients at TCH became more predictable in regard to stable hemodynamics, minimal bleeding, and less fluid requirements, we became more aggressive about extubating Fontan patients earlier. This is seen even during the study period in which the average length of intubation postoperatively decreased 77% during the 3.5 years to an average of 3.6 hours in 2006. In 2002, a select group of Fontan patients were being extubated within 30 minutes of arriving in the ICU. The advantage of waiting to get to the ICU, transferring care to another team, and then asking that team to extubate the patient within 30 minutes of arriving was unclear. The advantage of the anesthesia team extubating the patient in the OR where they had been managing the patient for the previous few hours was clear. Therefore, in 2002, all patients undergoing Fontan procedures were considered possible EOR candidates.
The flexibility of the anesthetic strategy is a central principle in EOR because the decision on whether EOR is appropriate for a particular patient is not made until the surgeon is ready to close the sternum. At that point, a summation of the preoperative factors and the intraoperative course is considered by the anesthesiologist and surgeon to make this decision. Unless there are particularly concerning preoperative hemodynamics or airway defects, the decision of EOR is mainly driven by the course of the operation (ie, stable hemodynamics, no concerning transesophageal echocardiographic findings, stable rhythm, and no bleeding) and the patient's emergence from anesthesia. The latter is an important aspect in the immediate postoperative management of these patients as the balance between adequate analgesia and excessive sedation (ie, hypoventilation) is important. Excessive sedation and the subsequent hypercarbia and increase in pulmonary vascular resistance are not well tolerated in Fontan patients. This result would also negate the advantage of decreasing intrathoracic pressure by means of early extubation. In the postoperative period, scheduled morphine and as-needed lorazepam are the typical medications chosen for analgesia and sedation. The use of regional anesthetics is particularly helpful in managing Fontan patients because it reduces the amount of opioids required for postoperative analgesia. Regional anesthetics have also been shown to attenuate the stress response from cardiopulmonary bypass [14, 15]. As demonstrated by the variance in EOR and non-EOR group size, ultimately extubation in the operating room is a clinical decision made by each individual surgeon and anesthesiologist.
Two authors in particular (J.S.H. and L.D.), who had experience with early extubation in congenital heart surgery from prior institutions, gave the EOR program a birth from which it grew, from 6% EOR in 2003 to more than 60% of all Fontans being EOR this past year [6]. This change in approach to patient care requires not only education but also a change in the mindset of the entire perioperative team. The close attention that EOR patients require within the first 12 hours postoperatively requires an institutional commitment. The restructuring of the TCH Heart Center in the years preceding 2002 to include a dedicated cardiovascular ICU built adjacent to the congenital cardiovascular ORs also facilitated the success of EOR. This proximity allows the anesthesiologists and intensivists to easily move between the OR and ICU settings so they can jointly care for these patients. This clinical flexibility may also explain why the criticism that EOR would cause undue delay between cases and thus OR inefficiency was not realized in this series, in which the average time from surgical end time to ICU admission was not different between the EOR and non-EOR groups. As the practical advantages of EOR for Fontan patients such as earlier inotropic agent weaning, shorter ICU and hospital stays, and an overall sense of a quicker recovery became obvious, more surgeons, anesthesiologists, and intensivists began promoting EOR at TCH. Now, it has become the standard of care at our institution and has been expanded to other patient populations, in which positive-pressure ventilation negatively impacts the hemodynamic state (eg, patients status post–bidirectional Glenn).
Analysis of the current series has affirmed the belief that there are hemodynamic benefits to EOR as demonstrated by the advantageous hemodynamics of the EOR group (ie, lower mean common atrial pressure and mean pulmonary arterial pressure, higher mean arterial pressure) compared with the non-EOR cohort in the immediate postoperative period. This was also confirmed by the fact that the inotropic scores at extubation were the same between the cohorts, but steadily diverged in the postoperative period to be statistically different. Although these hemodynamic changes between the EOR and non-EOR groups are statistically significant in the initial 12 hours postoperatively, the clinical significance of a 2- to 3-mm Hg difference in the mean pulmonary arterial pressure or mean common atrial pressure at an individual time point is unclear. The current series also demonstrated that the EOR strategy was quite effective in decreasing hospital utilization. In fact, if a patient was extubated in the OR, this would decrease their total hospital cost burden by 31% (Fig 3).
Even though the EOR and non-EOR groups were similar in many of the comparisons, there were obviously differences between the groups, because a nonblinded and nonrandom decision was made by the operative team to extubate or not. However, we do believe that for a select group of Fontan patients, EOR not only improved their postoperative hemodynamics but has changed our practice by shortening the time to each postoperative step, from weaning inotropic agents, to ICU discharge, to removing chest tubes, and discharging patients home. At TCH, these changes have resulted in a safe and decreased recovery time for Fontan patients.
|
Discussion |
|---|
|
TopAbstractIntroductionPatients and MethodsResultsCommentDiscussionReferences |
|---|
DR MORALES: Yes. We've extended this management strategy to our bidirectional Glenns over the last 2 to 3 years. Unfortunately, we have not formally collected their data at this time.
DR MUHAMMAD A. MUMTAZ (Cleveland, OH): David, I enjoyed your presentation. We have embarked on the same route, and a couple of things that I'd like to run by you and see what your experience is.
One thing is that for pain control we found something that's available commercially called a Lidoderm patch, which is a 5% lidocaine patch applied on the skin. And we now apply that routinely on our patients right next to the sternotomy, and their early postoperative pain is under very reasonable control. Have you had any experience with that?
The second thing was that when we started doing this a couple of years ago, we found that the balance of narcotics was very important, and we were having some early reintubations because of elevation in CO2. And what is the PCO 2 (arterial partial pressure of carbon dioxide) that you're willing to accept in the early postoperative period?
DR MORALES: We have not used a Lidoderm patch. We have been aggressive about using caudals preoperatively as well as Toradol postoperatively. These methods have allowed us to really limit our postoperative opioid use.
In terms of what carbon dioxide level we are willing to accept, we feel it is more important to evaluate the patient and as long as they are clinically stable we are willing to accept higher carbon dioxide levels. The proximity of our ORs (operating rooms) and ICU (intensive care unit) allow the anesthesiologist to stay with the patient in the ICU for approximately 30 minutes while the fellow gets the next patient ready. We feel that this is quite helpful since they extubated the patient and have the best feel for how the patient is doing. I think that the anesthesiologist's continued involvement with the patient outside the OR has been very helpful in avoiding reintubation.
DR MUMTAZ: The reason I bring out the issue of PCO 2 is that when we were just simply keeping them on the ventilator, the early protocol was that they would be normally ventilated, meaning their PCO 2 would be normal, which is 40.
But now when we extubate them, once in a while you see an elevation of PCO 2, and the PICU (pediatric ICIU) and ourselves included raised eyes and said, okay, is this a failure or not when the PCO 2 is 55, 57. And the kid looks okay, oxygen saturation is okay. And in a couple of them early on we reintubated, and a couple of them everybody was saying let's just watch, let's just watch, and then it's okay.
So, I mean, when you early extubate, then what is the typical PCO 2 you see and where do you draw the line and say that it isn't?
DR MORALES: We typically see PCO 2s right after arriving in the ICU in the 50s. But with patience and close observation, the levels will come down as they metabolize their sedatives. Limiting the opioids during this period is key.
DR KIRK R. KANTER (Atlanta, GA): In one of your early slides, you showed that early in your experience you had few early extubations, and in the past 2 years the majority had early extubation. Can you not, therefore, attribute your favorable results to a time effect in that you are getting better at doing Fontans?
Did you compare just the last 2 or 3 years where there's more of a concerted effort, and did you find the significant improvements that you reported when you looked at all the years?
DR MORALES: We did not compare the non-EOR and EOR groups over the past 2 to 3 years.
There is a time effect as you mentioned, and as excellent results have become more predictable, we have gotten more aggressive about extubation in the OR. Even though we've matched the EOR and non-EOR groups as best we can, they are different groups. The decision of whether or not to extubate a patient in the OR is a prospective one, and the reason one patient got extubated and not another is not always identifiable. Thus no matter how well the groups are statistically matched, they are different.
Whether the groups are matched or not, the main purpose of this study is to show that EOR is safe and that it can make a difference in one's practice. A patient coming out of the OR extubated is more likely to leave the next morning from the ICU than the same patient coming out of the OR not extubated.
DR CHRISTOPHER A. CALDARONE (Toronto, Ontario, Canada): Can I ask you to clarify one small point? You had said that the time from the OR to the ICU was the same in both groups, but I think the more relevant time interval would be the time from the end of the skin incision until they actually leave the operating room. Did that time interval vary between the groups? In other words, did you have to wait around for a while to get these patients extubated?
DR MORALES: The time measured was not the transport time from OR to ICU but the time from the drapes coming off to arriving in the ICU so I think this would have captured a "waiting around time" for extubation. Our time to get out of the OR was short, because we extubated many of the patients while the drapes were being taken off. Because our anesthesia attendings will go with the patient to the ICU and observe them there for a while, they don't wait around too long in the OR after extubating the patients.
We did try to look at the skin closure time until they left the OR, but I don't think those times were accurate because they were very short, much shorter than we expected. Therefore, we analyzed the time from the end of surgery, which was when the drapes were off and the bandages on, to the patient arriving in the ICU.
DR MARSHALL L. JACOBS (Philadelphia, PA): It was a very nice presentation, and I think the most important thing you demonstrated is that this program of extubation early is safe and effective.
My question is a little bit like Dr Kanter's but not precisely the same. I imagine all the patients benefited from your consciousness of this strategy. The ones who were extubated and weren't probably had an attentive focus on expediting their passage.
What I wonder, though, is that the end points that you measured of inotrope use, inotrope duration, ICU stay, hospital stay, if you looked at another era and stratified patients not by extubation in the operating room but by your inclusion or exclusion criteria, in other words, you didn't extubate the, quote, higher-risk patients, less good ventricular function, less good pulmonary artery status, the things that you talked about in your first few slides, I wonder if your outcome measures aren't determined as much by the patient features that were selection criteria for the strategy as they were by having the tube out in one room rather than another room.
DR MORALES: We did not compare our EOR group to a historical matched control, which perhaps would have strengthened the analysis. However, again I would emphasize that trying to retrospectively case-match the EOR group to any non-EOR group is virtually impossible since the decision to extubate was not blinded and made based on clinical data as well as the OR team's sense of how the patient was doing. Regardless of the data that was matched, there had to be something that made the OR team decide to extubate someone or not. This something may not always be identifiable. Therefore, the groups are inherently not matched.
It is possible that the criteria we used to extubate these patients selected out patients who would do better. However, from a practical standpoint, I still feel that if a patient comes out of the OR extubated that they will on average move through the ICU quicker than the same patient arriving to the ICU intubated. I believe that your first point is well stated in that the take home message here is that this strategy can be done safely and effectively.
|
References |
|---|
|
TopAbstractIntroductionPatients and MethodsResultsCommentDiscussionReferences |
|---|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| ANN THORAC SURG | ASIAN CARDIOVASC THORAC ANN | EUR J CARDIOTHORAC SURG |
| J THORAC CARDIOVASC SURG | ICVTS | ALL CTSNet JOURNALS |
