Mineto Kamata

Perioperative care of infants with pyloric stenosis

Pyloric stenosis (PS) is one of the most common surgical conditions affecting neonates and young infants. The definitive treatment for PS is surgical pyloromyotomy, either open or laparoscopic. However, surgical intervention should never be considered urgent or emergent. More importantly, emergent medical intervention may be required to correct intravascular volume depletion and electrolyte disturbances. Given advancements in surgical and perioperative care, morbidity and mortality from PS should be limited. However, either may occur related to poor preoperative resuscitation, anesthetic management difficulties, or postoperative complications. The following manuscript reviews the current evidence‐based medicine regarding the perioperative care of infants with PS with focus on the preoperative assessment and correction of metabolic abnormalities, intraoperative care including airway management (particularly debate related to rapid sequence intubation), maintenance anesthetic techniques, and techniques for postoperative pain management. Additionally, reports of applications of regional anesthesia for either postoperative pain control or as an alternative to general anesthesia are discussed. Management recommendations are provided whenever possible.

Remifentanil: applications in neonates

Remifentanil is a synthetic opioid derivative that was introduced into clinical practice in the United States in 1996. The unique modification of its chemical structure to include a methyl-ester ring allows its hydrolysis by non-specific plasma and tissue esterases. This molecular configuration results in its rapid metabolism thereby providing a rapid onset, easy titration by continuous infusion, and a short context-sensitive half-life with rapid elimination. These principles are stable and consistent across all age groups regardless of the infusion characteristics. Owing to these pharmacokinetic characteristics, it is an effective agent in the neonatal population allowing the provision of intense analgesia and anesthesia with a rapid recovery profile in various clinical scenarios. Here, we review the pharmacokinetics of remifentanil in neonates, discuss its clinical applications including intraoperative administration for anesthetic care, unique applications for procedural sedation including endotracheal intubation, and its potential use for sedation in the Intensive Care Unit setting during mechanical ventilation.

Residual volume in the cuff of the endotracheal tube when the pilot balloon is torn off instead of deflated using a syringe

BACKGROUND In recent years, there has been a shift in airway management with the use of cuffed endotracheal tubes (ETT) in pediatric patients. While the use of a syringe to deflate the cuff is generally recommended, anecdotal observations suggest that some healthcare practitioners tear off the pilot balloon from ETT to deflate the cuff. This study was conducted to estimate the residual volume in the cuff when the pilot balloon is torn off for deflation. METHOD The in vitro study was conducted in three phases. In phases 1 and 2, various sized cuffed ETTs (3.0, 4.0, and 5.0 mm) were inflated to achieve an intracuff pressure of 20-30 cmH2O in open atmosphere (phase 1) or inside a tube to simulate external pressure from the tracheal wall (phase 2). The pilot balloons were ripped off and the residual volume in the cuff was measured. The process was repeated using 10 ETTs of each of the 3 sizes. In phase 3, the same process was repeated using ten, size 7.0 cuffed ETTs inflated in an intubating mannequin. RESULTS In phase 1, the percentage of the remaining residual volume was 60.7, 72.8, and 69.5% in 3.0, 4.0, and 5.0 mm ETTs respectively. Although the percentage of residual volume in phases 2 and 3 was less than phase 1, the residual volume in phases 2 and 3 still averaged approximately 60-70% of the volume required for cuff inflation. In one case, the pilot balloon tube was completely occluded and the residual volume in the cuff could not be expelled even with external pressure. CONCLUSION Since significant percentage of the volume remained in the cuff after tearing off the pilot balloon tube with one being completely occluded, we would not recommend this method for cuff deflation.

Perioperative care in an adolescent patient with heparin-induced thrombocytopenia for placement of a cardiac assist device and heart transplantation: case report and literature review

Heparin-induced thrombocytopenia (HIT) can cause life-threatening complications following the administration of heparin. Discontinuation of all sources of heparin exposure and the use of alternative agents for anticoagulation are necessary when HIT is suspected or diagnosed. We present the successful use of bivalirudin anticoagulation in an adolescent patient during cardiopulmonary bypass who underwent both placement of a left ventricular assist device and subsequent heart transplantation within a 36-hour period. The pathophysiology and diagnosis of HIT are reviewed, previous reports of the use of direct thrombin inhibitors for cardiac surgery are presented, and potential dosing regimens for bivalirudin are discussed.

An In Vitro Assessment of the Efficacy of Various IV Cannulas for the Rapid IV Fluid Administration

Objectives: The current study prospectively evaluates the administration of fluid through commonly used vascular cannulas of various length and diameter. Design: Observational, in vitro experiment. Setting: Not applicable. Subjects: No human subjects. Interventions: None. Measurements and Main Results: Fluid (500 mL) was administered via gravity flow and with pressure assistance (pressure bag set at 300 mm Hg) through various vascular cannulas including peripheral IV catheters (22 gauge, 1 inch; 20 gauge, 1.16 and 1.88 inch; and 18 gauge, 1.16 and 1.88 inch), 3-Fr central line lumens (lengths 50, 80, and 120 mm), and a 4-Fr, 10 cm Micropuncture catheter (Cook Medical, Bloomington, IN). During gravity flow, drain time decreased by approximately 50% when moving from a 22 to 20 to 18 gauge cannula and increased by approximately 20% as the catheter length increased from 50 to 80 to 120 cm. Flow rates were highest with the Micropuncture catheter, which achieved a drain time of 2.7 minutes for the 500 mL bag when infused with pressure assistance. Conclusions: In general, the delivery of crystalloid solutions through commonly used vascular cannulas was fastest with larger diameter and shorter length cannulas. Pressure-assisted flow was able to partially compensate for the increased resistance with smaller and longer catheters. The unique design of the tip of the Micropuncture catheter compensated for the increased length and allowed for rapid fluid delivery. This design may compensate for the increased length when longer catheters are needed for ultrasound-guided placement.

General anesthesia with a native airway for patients with mucopolysaccharidosis type III

Mucopolysaccharidosis type III is a progressive disease with worsening airway, pulmonary, and cardiac involvement that may complicate anesthetic care.

The Effect of Transesophageal Echocardiography Probe Placement on Intracuff Pressure of an Endotracheal Tube in Infants and Children

OBJECTIVES To evaluate the effects of transesophageal echocardiography (TEE) probe insertion on the endotracheal cuff pressure (CP). DESIGN Prospective observational study. SETTING Single standing, not-for-profit pediatric hospital. PARTICIPANTS A total of 80 pediatric patients (aged 6 days to 18.4 years) who underwent cardiac surgery and intraoperative TEE. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS Following anesthesia induction and endotracheal intubation, the CP was recorded at 4 points: before the insertion of the TEE (P1), at TEE insertion (P2), during TEE examination (P3), and after the probe was advanced into the stomach (P4). Twenty patients were enrolled in each of the following age groups:<1 year of age; 1-4 years of age; 5-8 years of age; and 9-18 years of age. CP was compared between pairs of time points using paired t-tests, and differences in CP over time were compared among age groups using repeated-measures analysis of variance. CP at P1, P2, P3, and P4 was 18.7±11.6, 26.7±14.4, 22.3±12.4, and 20.6±12.6 cmH2O, respectively. Although CP significantly increased from P1 to P2 (p<0.001), there was no significant difference between P1 and P4 (95% CI; -0.3 to 4.1; p = 0.083). There was no significant difference in CP change based on the age of the patient. CONCLUSION Following a transient increase in CP with TEE probe insertion, the CP returned to baseline after the tip of the TEE probe was advanced into the stomach. There was no variation among age groups in the magnitude of the CP change during the study.

A Retrospective Analysis of the Influence of Ventricular Morphology on the Perioperative Outcomes After Fontan Surgery

OBJECTIVES The objectives of this study were to evaluate the effect of ventricular morphology on perioperative outcomes during Fontan surgery. DESIGN Retrospective cohort study. SETTING Single standing, not-for-profit pediatric hospital. PARTICIPANTS A total of 72 patients who underwent Fontan surgery using cardiopulmonary bypass without aortic cross-clamp between January 1, 2009 and December 31, 2014. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS The patients were divided into 3 categories depending on their single-ventricle lesions: (1) LV group (n = 20): left dominant and hypoplastic right ventricle; (2) RV group (n = 37): right dominant and hypoplastic left ventricle; and (3) BV group (n = 15): biventricular or indeterminate dominance. Perioperative major adverse events were collected based on the Society of Thoracic Surgeons database. The need for perioperative allogeneic blood transfusions also was determined. The mean age was 3.3±1.7 years and the mean weight was 13.6±4.0 kg. All patients had extracardiac lateral tunnel or conduit Fontan procedures. Sixty-nine of the patients (96%) underwent tracheal extubation in the operating room. Anesthesia, surgery, and CPB times were 326±68, 239±73, and 70±41 minutes, respectively. Eleven patients (15%) required allogeneic blood products intraoperatively, while 30 patients (42%) required allogeneic blood products during the perioperative period. Length of cardiac intensive care unit stay and hospital stay (median [IQR]) were 1 [1,2] and 12 [9,18] days, respectively. There was no mortality and no significant differences between groups in major postoperative complications, anesthetic or surgical variables. CONCLUSIONS No difference in the immediate perioperative outcomes was noted based on ventricular morphology.