Liposomal Bupivacaine Infiltration After Median Sternotomy in Pediatric Cardiac Surgery

OBJECTIVE

The present study retrospectively ascertained whether liposomal bupivacaine (LB) injected subcutaneously after median sternotomy incisions in pediatric cardiac surgery patients is as efficacious as the ON-Q PainBuster pump (ON-Q) (Avonas Medical, Alpharetta, GA).

DESIGN

Retrospective cohort comparison.

SETTING

Pediatric hospital.

PARTICIPANTS

Cardiac surgery patients who were treated with LB for elective cardiac surgery.

INTERVENTIONS

Patients received 4 mg/kg of LB admixed with 0.25% bupivacaine and 0.9% normal saline. These patients were compared with an age- and procedure-matched control group of similar size treated with the ON-Q pump (continuous infusion 0.25% bupivacaine via subcutaneous catheter). Total analgesics used and route, other analgesics or sedatives, and pain scores (first 24 hours and cumulative) were tracked for 96 hours after surgery.

MEASUREMENTS AND MAIN RESULTS

A total of 222 patients were equally divided between the two groups. Overall, the median (interquartile range) age was 6.5 (3.8-12.7) years. Unadjusted analysis suggested that patients in the LB group were administered a significantly higher dose of intravenous acetaminophen (77.4 v 60.0 mg/kg; p < 0.05). Extubation in the operating room was significantly higher in the LB patients (p < 0.05). Narcotic (morphine) administration was significantly higher in the ON-Q group (100.0% v 95.5%; p < 0.05). Although the median pain score within the first 24 hours was higher in LB patients (27.0 v 17.0; p < 0.05), there was a significantly greater difference observed in the Numeric Rating Scale area under the curve for the ON-Q group.

CONCLUSIONS

LB is at least as effective as the ON-Q is for providing analgesia after median sternotomy incision in children.

Three-year experience with immediate extubation in pediatric patients after congenital cardiac surgery

Background

In pediatric cardiac anesthesiology, there is increased focus on minimizing morbidity, ensuring optimal functional status, and using health care resources sparingly. One aspect of care that has potential to affect all of the above is postoperative mechanical ventilation. Historically, postoperative ventilation was considered a must for maintaining patient stability. Ironically, it is recognized that mechanical ventilation may increase risk of adverse outcomes in the postoperative period. Hence, many institutions have advocated for immediate extubation or early extubation after many congenital heart surgeries which was first reported decades ago.

Methods

637 consecutive patient charts were reviewed for pediatric patients undergoing cardiac surgery with cardiopulmonary bypass. Patients were placed into three groups. Those that were extubated in the operating room (OR) at the conclusion of surgery (Immediate Extubation or IE), those that were extubated within six hours of admission to the ICU (Early Extubation or EE) and those that were extubated sometime after six hours (Delayed Extubation or DE). Multiple variables were then recorded to see which factors correlated with successful Immediate or Early Extubation.

Results

Overall, 338 patients (53.1%) had IE), 273 (42.8%) had DE while only 26 patients (4.1%) had EE. The median age was 1174 days for the IE patients, 39 days for the DE patients, whereas 194 days for EE patients (p < 0.001). Weight and length were also significantly different in at least one extubation group from the other two (p < 0.001). The median ICU LOS was 3 and 4 days for IE and EE patients respectively, whereas it was 9.5 days for DE patients (p < 0.001). DE group had a significant longer median anesthesia time and cardiopulmonary bypass time than the other two extubation groups (p > 63,826.88 < 0.001). Regional low flow perfusion, deep hypothermia, deep hypothermic circulatory arrest, redo sternotomy, use of other sedatives, furosemide, epinephrine, vasopressin, open chest, cardiopulmonary support, pulmonary edema, syndrome, as well as difficult intubation were significantly associated with delayed extubation (IE, EE or DE).

Conclusions

Immediate and early extubation was significantly associated with several factors, including patient age and size, duration of CPB, use of certain anesthetic drugs, and the amount of blood loss and blood replacement. IE can be successfully accomplished in a majority of pediatric patients undergoing surgery for congenital heart disease, including in a minority of infants.

Interval changes in ROTEM values during cardiopulmonary bypass in pediatric cardiac surgery patients

Introduction

Rotational thromboelastometry (ROTEM) has been shown to reduce the need for transfused blood products in adult and pediatric cardiac surgery patients. However, similar evidence in newborns, neonates, and young infants is lacking. We quantified ROTEM value changes in pediatric patients on cardiopulmonary bypass (CPB) before, during and after blood product transfusion.

Methods

Each surgery had at least four interventions: initiating CPB; platelet administration during rewarming phase; post-CPB and following protamine and human fibrinogen concentrate (HFC) administration; and further component therapy if bleeding persisted and ROTEM indicated a deficiency. ROTEM assays were performed prior to surgery commencement, on CPB prior to platelet administration and following 38 mL/kg platelets, and post-CPB after protamine and HFC administration. ROTEM assays were also performed in the post-CPB period after further blood component therapy administration.

Results

Data from 161 patients were analyzed. Regression models suggested significant changes in HEPTEM clotting time after all interventions. PLT administration during CPB improved HEPTEM α by 22.1° (p < 0.001) and FIBTEM maximum clot firmness (MCF) by 2.9 mm (p < 0.001). HFC administration after CPB termination significantly improved FIBTEM MCF by 2.6 mm (p < 0.001). HEPTEM MCF significantly increased after 3/4 interventions. HEPTEM α significantly decreased after two interventions and significantly increased after two interventions. Greatest perturbances in coagulation parameters occurred in patients ≤90 days of age.

Conclusion

CPB induced profound perturbations in ROTEM values in pediatric cardiac surgery patients. ROTEM values improved following PLT and HFC administration. This study provides important clinical insights into ROTEM changes in pediatric patients after distinct interventions.

Correlation Between ROTEM FIBTEM Maximum Clot Firmness and Fibrinogen Levels in Pediatric Cardiac Surgery Patients

This study evaluated whether rotational thromboelastometry (ROTEM; Tem International GmbH, Munich, Germany) FIBTEM maximum clot firmness (MCF) can be used to predict plasma fibrinogen level in pediatric patients undergoing cardiac surgery. Linear regression was conducted to predict plasma fibrinogen level using FIBTEM MCF (0.05 level of significance). Scatter plot with the regression line for the model fit was created. Fifty charts were retrospectively reviewed, and 87 independent measurements of FIBTEM MCF paired with plasma fibrinogen levels were identified for analysis. Linear regression analysis suggested a significant positive linear relationship (P < .0001) between plasma fibrinogen levels and MCF. Both MCF intercept and slope were significantly correlated with fibrinogen level (P < .0001). The estimated regression equation (predicted fibrinogen = 78.6 + 12.4 × MCF) indicates that a 1-mm increase in MCF raises plasma fibrinogen level by an average of 12.4 mg/dL. The statistically significant positive linear relationship observed between MCF and fibrinogen levels (P < .001) suggests that MCF can be used as a surrogate for fibrinogen level. This relationship is of clinical relevance in the calculation of patient-specific dosing of fibrinogen supplementation in this setting.

Dexmedetomidine use in patients undergoing electrophysiological study for supraventricular tachyarrhythmias

BACKGROUND

Dexmedetomidine is a selective alpha-2 adrenergic agonist with sedative, analgesic, and anxiolytic properties. Dexmedetomidine has not been approved for use in pediatrics. Dexmedetomidine has been reported to depress sinus node and atrioventricular nodal function in pediatric patients; it has been suggested that the use of dexmedetomidine may not be desirable during electrophysiological studies.

AIM

We hypothesize that the use of dexmedetomidine does not inhibit the induction of supraventricular tachyarrhythmias (SVT) during electrophysiological studies and does not inhibit the ablation of such arrhythmias.

METHODS

In this retrospective, observational cohort study, we reviewed all cases presenting to the cardiac catheterization laboratory for diagnosis or treatment of SVT since 2007. All cases were performed by the same electrophysiologist. The anesthesia was provided by one of the three cardiac anesthesiologists. One cardiac anesthesiologist did not use dexmedetomidine during electrophysiological studies. A second used dexmedetomidine, but only with an infusion. The third used dexmedetomidine with a primary bolus and an infusion. Thus, the patients were stratified into three different groups: Group 1 patients did not receive any dexmedetomidine. Group 2 patients received a dexmedetomidine infusion of 0.5-1 μg·kg^-1 ·h^-1 . Group 3 patients received a dexmedetomidine infusion of 0.5-1 μg·kg^-1 ·h^-1 and a dexmedetomidine bolus prior to the infusion of 0.5-1 μg·kg^-1 . We then compared those patients for the following variables: demographic data including age, sex, height, weight; anesthetic data such as, mask vs intravenous induction, identity of induction agent, amount of sevoflurane and propofol used; amount of dexmedetomidine used; presence of congenital heart disease and other comorbidities; the need for isoproterenol and dose, the need for adenosine and dose, and the need for any other medications to affect rhythm both before and after radiofrequency ablation; the ability to induce the arrhythmia, the type of arrhythmia, the presence of Wolff-Parkinson-White syndrome, the presence of an accessory pathway, the ablation rate, and the recurrence rate.

RESULTS

There was no difference in the anesthetic agents, except there was a lesser amount of propofol used in the dexmedetomidine groups (χ²₍₂₎ = 48.2, P < 0.001). There was no difference in the electrophysiological parameters among groups, except the Group 1 patients did require the use of isoproterenol in the preablation period less often compared to the dexmedetomidine groups (χ²₍₂₎ = 15.2, P < 0.01). However, with the greater use of isoproterenol, there was no difference in the ability to induce the arrhythmia. Moreover, the percentage of patients ablated, and the recurrence rate among groups was the same.

CONCLUSIONS

We conclude that dexmedetomidine does not interfere with the conduct of electrophysiological studies for SVT and the successful ablation of such arrhythmias. However, dexmedetomidine use did result in a greater need for isoproterenol.

Initial experience with dexmedetomidine for diagnostic and interventional cardiac catheterization in children

BACKGROUND

Children undergoing diagnostic and interventional cardiac catheterization require deep sedation or general anesthesia (GA). Dexmedetomidine, a selective alpha-2 adrenergic agonist, has sedative, analgesic and anxiolytic properties without respiratory depression. These characteristics make it potentially suitable as a sedative agent during diagnostic procedures in children. We report our experience using dexmedetomidine in 20 children aged 3 months to 10 years undergoing cardiac catheterization.

METHODS

Following a midazolam premedication, intravenous access was secured facilitated by the inhalation of sevoflurane in oxygen. A loading dose of 1 microg x kg(-1) dexmedetomidine was administered over 10 min followed by an initial infusion rate of 1 microg x kg(-1) x h(-1). Nasal cannulae were applied, allowing endtidal CO2 monitoring with the patients breathing spontaneously. Hemodynamic parameters, Bispectral Index Score (BIS) and sedation score were measured every 5 min. Patient movement or evidence of inadequate sedation were treated with propofol (1 mg x kg(-1)). The dexmedetomidine infusion rate was titrated to the level of sedation to a maximum of 2 microg x kg(-1) x h(-1) to maintain a sedation score of 4-5 and a BIS value <80.

RESULTS

Five patients (25%) had some movement on local infiltration or groin vessel access. This did not necessitate restraint or result in difficulty securing vascular access. No patients failed sedation that required the addition of another sedative agent or conversion to GA; eight patients were sedated with dexmedetomidine alone; however, 12 (60%) patients did receive a propofol bolus at some time during the procedure due to movement, increasing BIS value or in anticipation of stimulation. There were no incidences of airway obstruction or respiratory depression. In all cases the heart rate and blood pressure remained within 20% of baseline. No patient required treatment for profound bradycardia or hypotension. The average infusion rate for dexmedetomidine following the loading dose was 1.15 (+/-0.29)microg x kg(-1) x h(-1) (range 0.6-2.0 microg x kg(-1) x h(-1)).

CONCLUSIONS

This initial experience showed dexmedetomidine, with or without the addition of propofol, may be a suitable alternative for sedation in spontaneously breathing patients undergoing cardiac catheterization.

Diminished Blalock-Taussig shunt flow detected by cerebral oximetry

Near-infrared spectroscopy is a noninvasive optical technique used to monitor brain tissue oxygenation. Measurement of cerebral oxygenation is a more sensitive monitor of oxygen delivery to the brain than other available monitors. Prolonged cerebral desaturation is correlated with poor neurological outcomes. We report a case where the cerebral oximeter alerted us to diminished blood flow in a preexisting Blalock-Taussig (subclavian artery to pulmonary artery) shunt.

Perioperative effects of oral ketorolac and acetaminophen in children undergoing bilateral myringotomy

Prophylactic administration of analgesics before surgery can decrease the intraoperative anaesthetic requirement and decrease pain during the early postoperative period. In a double-blind, placebo-controlled study involving 90 healthy ASA physical status I or II children undergoing bilateral myringotomy, we compared the postoperative analgesic effects of oral acetaminophen and ketorolac, when administered 30 min before induction of anaesthesia. Patients were randomized to receive saline (0.1 ml.kg-1), acetaminophen (10 mg.kg-1) or ketorolac (1 mg.kg-1) diluted in cherry syrup to a total volume of 5 ml. Anaesthesia was induced and maintained with halothane and nitrous oxide via a face mask. Postoperative pain was assessed by a blinded observer using an objective pain scale. The three study groups were similar with respect to demographic data, duration of anaesthesia and surgery, induction behaviour, oxygen saturation, incidence of postoperative emesis and, recovery times. The ketorolac group had lower postoperative pain scores and required less frequent analgesic therapy in the early postoperative period compared with the acetaminophen and placebo groups. In contrast, there were no differences in pain scores or analgesic requirements between the acetaminophen and the placebo groups. We conclude that the preoperative administration of oral ketorolac, but not acetaminophen, provided better postoperative pain control than placebo in children undergoing bilateral myringotomy.

Anesthesia for Selective Dorsal Rhizotomy in Children

Anesthetic records for the first 71 children who underwent selective dorsal rhizotomy (SDR) at our hospital were reviewed. Anesthesia during SDR must preserve muscle contraction in response to direct electrical stimulation of the dorsal nerve rootlets. In our experience, halothane, isoflurane, and narcotics do not interfere with electrophysiologic monitoring, even though relatively large doses are required during SDR. Propofol proved to be unacceptable as an anesthetic because of severe muscle spasms during electrical stimulation of the nerve rootlets. The body temperature rises predictably during the stimulation phase of SDR and active warming measures should be avoided.

Comparison of ketorolac and morphine as adjuvants during pediatric surgery

The intraoperative use of opioid analgesics decreases the volatile anesthetic requirement and provides for pain relief in the early postoperative period. In a randomized double-blind, placebo-controlled study involving 95 ASA physical status 1 or 2 children (ages 5-15 yr) undergoing general anesthesia for elective operations, we compared postoperative analgesia following the intraoperative intravenous (iv) administration of ketorolac, a nonsteroidal antiinflammatory drug or morphine, an opioid analgesic. After induction of general anesthesia and before the start of the surgical procedure, children received equal volumes of saline, morphine (0.1 mg.kg-1, iv) or ketorolac (0.9 mg.kg-1, iv). Postoperative pain was evaluated by the child using a 10-cm linear visual analog scale (VAS) and by a blinded observer using both a VAS and an objective pain scale (OPS) in the postanesthesia care unit (PACU). There were no statistically significant differences in the VAS and OPS scores in the PACU or in the postoperative analgesic requirements in children receiving morphine or ketorolac. The placebo group had a significantly higher VAS and OPS score and required earlier and more frequent analgesic therapy in the PACU compared to the two analgesic groups. Patients receiving ketorolac had less postoperative emesis than those receiving morphine. We conclude that ketorolac (0.9 mg.kg-1) is an effective alternative to morphine (0.1 mg.kg-1) as an iv adjuvant during general anesthesia, and in the dose used in this study, is associated with less postoperative nausea and vomiting in children.

Effect of intraoperative analgesic therapy on end-expired concentrations of halothane associated with spontaneous eye opening in children

We studied 94 healthy ASA physical status I or II children to determine the end-expired concentration of halothane associated with eye opening on emergence from anesthesia, and to determine if parenteral opioid therapy or regional analgesia significantly altered this concentration. In our study, anesthesia was maintained with halothane in an air-oxygen mixture. After the surgical procedure was completed, the inspired concentration of halothane was adjusted to zero and the end-expired concentrations were permitted to decrease spontaneously. The end-expired concentration at which the child spontaneously opened his or her eyes was recorded. There were no statistically significant differences in the values of the end-expired halothane concentration at eye opening between patients in the control group, who did not receive any supplementation of halothane anesthesia, and patients in the groups that received either morphine supplementation or regional analgesia. These data suggest that analgesia and hypnosis (or loss of consciousness) occur by different mechanisms during halothane anesthesia in children.