Pierantonio Russo

Dexmedetomidine in the treatment of withdrawal syndromes in cardiothoracic surgery patients.

Dexmedetomidine (Precedex, Abbott Laboratories, Abbott Park, IL) is an• 2adrenergic agonist that possesses a high ratio of specificity for the• 2versus the• 1receptor. It is currently approved for the provision of sedation during mechanical ventilation in adults. Given previous experience with clonidine for the treatment of substance withdrawal and the preliminary anecdotal experience with dexmedetomidine, it appears that dexmedetomidine may be a useful agent for treatment of substance withdrawal in the intensive care setting. The authors present their experience with the use of dexmedetomidine to control withdrawal behavior in 3 patients following cardiothoracic surgery. Previous reports regarding the use of dexmedetomidine to treat withdrawal and its potential application in this clinical arena are reviewed.

Additional experience with dexmedetomidine in pediatric patients.

Purpose This study evaluates the efficacy of dexmedetomidine in clinical scenarios other than sedation during mechanical ventilation. Methods We conducted a retrospective chart review and presentation of case series of children in the pediatric intensive care unit and the postanesthesia care unit who received dexmedetomidine. Results Dexmedetomidine was administered by continuous infusion to three patients and as a single bolus dose (0.5 &mgr;g/kg) to two patients. In the five clinical scenarios, dexmedetomidine provided effective sedation during spontaneous ventilation in two patients, reversed the clinical signs and symptoms of withdrawal from illicit substances in one patient, and was effective in the treatment of postanesthesia emergence delirium and shivering in two additional patients. Conclusion These preliminary data suggest that dexmedetomidine may be an effective agent for sedation in spontaneously breathing patients, in the treatment of drug withdrawal, and in the treatment of two common postanesthesia problems.

Use of a ventricular assist device as a bridge to transplantation in a patient with single ventricle physiology and total cavopulmonary anastomosis

Mechanical circulatory support can be used to manage acute and chronic cardiac failure in both adult and pediatric patients. Traditionally, extracorporeal membrane oxygenation (ECMO) has been the most common form of mechanical circulatory support in children. However, more recently, in cases of pure ventricular dysfunction, ventricular assist devices (VADs) have offered specific advantages over ECMO, including better ventricular recovery, reduced anticoagulation requirements, decreased use of blood products and decreased cost. We present the use of a VAD in an adolescent with single‐ventricle physiology, who could not be weaned from cardiopulmonary bypass (CPB) after undergoing a revision of a modified Fontan operation. Gas exchange was provided by the patient’s lungs while the centrifugal VAD was used successfully to support the circulation as a bridge, first to a totally implantable pulsatile VAD and subsequently to heart transplantation.

Preliminary Experience With Nesiritide in the Pediatric Population

Nesiritide is a recombinant formulation of brain-type natriuretic factor. Preliminary experience in the adult population suggests that nesiritide may be an effective agent in the treatment of decompensated congestive heart failure. Given its physiologic effects, it may be an effective agent in the pediatric population; however, to date, there are no reports regarding its use in infants and children. The authors retrospectively review their experience with nesiritide in 5 pediatric patients. The cohort of 5 patients included a diverse population with 2 patients who were status postcardiothoracic surgery, 2 with adult respiratory distress syndrome, and 1 in the recovery phase from septic shock. Although no direct measurement of cardiac output was feasible as none of the patients had a pulmonary artery catheter, other indicators of increased cardiac output were noted. These included improved peripheral perfusion with warming of the extremities and improvement of peripheral pulses in all of the patients, increased venous saturation in 2 of the patients, and maintenance of or increased urine output despite weaning or discontinuation of diuretics. In 3 of the patients, nesiritide was started as the primary agent to provide a decrease in systemic vascular resistance and augment cardiac output, while in the other 2 patients, nesiritide was used when other vasoactive agents failed to provide the desired effect or resulted in adverse effects.

Argatroban for anticoagulation during cardiopulmonary bypass in an infant

Heparin induced thrombocytopenia (HIT) is a rare, but potentially life‐threatening complication of heparin therapy. In patients with HIT, alternative means of anticoagulation are necessary. The authors present an infant with HIT who required anticoagulation during cardiopulmonary bypass for tricuspid valve excision in the treatment of bacterial endocarditis. The direct thrombin inhibitor, argatroban, was successfully used. Previous reports regarding the use of argatroban and other nonheparin anticoagulants for anticoagulation are reviewed and suggestions regarding argatroban dosing in infants are presented.

Perioperative care of the patient with Williams syndrome

Williams syndrome, initially described by Williams, Barratt–Boyes, and Lowe in 1961, consists of characteristic dysmorphic features, congenital heart disease, and distinctive behavioral and emotional traits. In addition to acquired and congenital heart disease, manifestations in the renal, endocrine, musculoskeletal, and central nervous system may have implications during the perioperative period. Congenital and acquired heart disease can be a significant issue as sudden death, related to abnormalities of the coronary arteries, has been reported perioperatively in these patients. The authors present a 7‐month‐old infant, previously diagnosed with Williams syndrome, who required anesthetic care for repair of subaortic and supravalvular aortic stenosis. The potential perioperative implications of Williams syndrome are discussed.

Tissue Plasminogen Activator as an Adjuvant Therapy for Pleural Empyema in Pediatric Patients

The authors retrospectively review the clinical course and outcome of 6 pediatric patients, ranging in age from 2 to 13 years, who were treated with TPA for complex empyema. Efficacy was assessed by evaluating pleural fluid drainage for 6 hours prior to and subsequent to each dose of TPA, as well as by resolution of fever and length of hospital stay. The average volume drained for 6 hours before infusion of TPA was 22.5 mL ± 18.4 mL, and the average volume 6 hours after TPA therapy was 141.7 mL ± 28.3 mL, P < .0001. After initiation of TPA therapy, 5 out of 6 patients became afebrile within 48 hours. The median length of stay after initiation of TPA therapy was 6 days, with a range from 4 days to 12 days. A discussion of other current therapies for empyema, along with a comparison of these therapies to TPA regarding the costs of therapies and risk-benefit ratios, is also included.

Nesiritide during extracorporeal membrane oxygenation.

Nesiritide is a recombinant formulation of B‐type natriuretic peptide (BNP). Preliminary experience in the adult population has shown nesiritide to be an effective agent in the treatment of decompensated congestive heart failure (CHF) in adults. Given its physiological effects, it may be an effective agent in other clinical scenarios. We report the use of nesiritide in two infants during extracorporeal membrane oxygenation (ECMO). In one patient, nesiritide in doses up to 0.09 μg·kg−1·min−1 were used to control mean arterial pressure while in the other patient, doses of 0.01–0.03 μg·kg−1·min−1 were used to augment urine output. The potential applications of nesiritide and dosing regimens for this agent in the ECMO population are discussed.

Noninvasive Monitoring of Carbon Dioxide in Infants and Children With Congenital Heart Disease: End-Tidal Versus Transcutaneous Techniques

End-tidal CO 2 (ET CO 2 ) monitoring and transcutaneous (TC) CO 2 monitoring were prospectively compared in 53 patients, 1 month to 16 years of age, with congenital heart disease (CHD). There were 32 patients with cyanotic CHD and 21 with acyanotic CHD. The TC-Pa CO 2 difference was 2 ± 1 mm Hg and the ET-Pa CO 2 difference was 5 ± 3 mm Hg ( P < .0001). The TC-Pa CO 2 difference was≤2 mm Hg in 30 of 53 patients and≤5 mm Hg in 53 of 53 patients. The ETPa CO 2 difference was≤2 mm Hg in 9 of 53 patients and≤5 mm Hg in 30 of 53 patients ( P < .001). No variation in the TC-Pa CO 2 difference was noted based on the type of CHD (acyanotic vs cyanotic) or age. The ET-Pa CO 2 difference was greater in patients with cyanotic versus acyanotic CHD (7 ± 3 mm Hg vs 4 ± 2 mm Hg, P < .0001) and in patients≤1 year of age versus patients ≥1 year of age (6 ± 3 mm Hg vs 4 ± 2, P = .008). In infants and children with CHD, TC monitoring provides a more accurate estimation of Pa CO 2 than ET monitoring.

Changes in near infrared spectroscopy during deep hypothermic circulatory arrest.

Monitoring cerebral oxygenation with near infrared spectroscopy may identify periods of cerebral desaturation and thereby the patients at risk for perioperative neurocognitive issues. Data regarding the performance of near infrared spectroscopy monitoring during deep hypothermic circulatory arrest are limited. The current study presents data regarding use of a commercially available near infrared spectroscopy monitor during deep hypothermic circulatory arrest in paediatric patients undergoing surgery for congenital heart disease. The cohort included 8 patients, 2 weeks to 6 months of age, who required deep hypothermic circulatory arrest for repair of congenital heart disease. The baseline cerebral oxygenation was 63 +/- 11% and increased to 88 +/- 7% after 15 min of cooling to a nasopharyngeal temperature of 17-18 degrees C on cardiopulmonary bypass. In 5 of 8 patients, the cerebral oxygenation value had achieved its peak value (either >or=90% or no change during the last 2-3 min of cooling on cardiopulmonary bypass). In the remaining 3 patients, additional time on cardiopulmonary bypass was required to achieve a maximum cerebral oxygenation value. The duration of deep hypothermic circulatory arrest varied from 36 to 61 min (43.4 +/- 8 min). After the onset of deep hypothermic circulatory arrest, there was an incremental decrease in cerebral oxygenation to a low value of 53 +/- 11%. The greatest decrease occurred during the initial 5 min of deep hypothermic circulatory arrest (9 +/- 3%). Over the entire period of deep hypothermic circulatory arrest, there was an average decrease in the cerebral oxygenation value of 0.9% per min (range of 0.5 to 1.6% decline per minute). During cardiopulmonary bypass, cooling and deep hypothermic circulatory arrest, near infrared spectroscopy monitoring followed the clinically expected parameters. Such monitoring may be useful to identify patients who have not achieved the highest possible cerebral oxygenation value despite 15 min of cooling on cardiopulmonary bypass. Future studies are needed to define the cerebral oxygenation value at which neurological damage occurs and if interventions to correct the decreased cerebral oxygenation will improve perioperative outcomes.