Sonoclot® predicts operation time and blood loss after cardiopulmonary bypass in children.

Background: As the circulating blood volume is relatively small in pediatric patients, blood components are quickly lost when bleeding, which make it more difficult to stop the bleeding. Particularly in pediatric cardiac surgery, loss of clotting factors associated with cardiopulmonary bypass (CPB) would likely to be prominent. As a result, bleeding is further promoted and the operation time is extended. In order to search for the relation between clotting factors and the amount of bleeding, we used a viscoelastic point of care test. Objectives: We used Sonoclot® as viscoelastic point of care test to evaluate coagulation function before CPB and before weaning from CPB in pediatric cardiac surgery. Design: Retrospective. Setting: Single-institutional. Participants: We included 55 pediatric patients (median age 13 months [IQR 5-32]) who underwent cardiac surgery under CPB from December 2015 to November 2016. Interventions: None. Measurements and main results: Sonoclot® analysis was performed after induction of anesthesia (pre-data, or baseline data) and before any heparinized saline was given, and right after modified ultrafiltration after weaning from CPB (post-data). Post-data was compared with post-CPB operation time and post-CPB blood loss by multiple regression analysis. Furthermore, effects of fresh frozen plasma (FFP) added on CPB on coagulation function and post-platelet function (describe as PFSC) was assessed. Activated coagulation time (describe as ACTSC) and clot rate (describe as CRSC) showed no significant change between baseline data and post-data. Post-PFSC was worsened by prolonged CPB time (p < 0.05) and correlated to bleeding amount and operation time after CPB (p < 0.05). Total amount of platelet concentrate (PC) transfused was higher in patients with smaller PFSC (p < 0.05). Total amount of FFP and PC transfused correlated with bleeding amount and operation time after CPB (p < 0.05). In the subgroup analysis, PFSC declined in the FFP-included group, whereas there was no significant difference in coagulation function. Addition of FFP to CPB did not significantly affect CR, whereas PFSC deteriorated as CPB time was prolonged (CPB time = 1/(0.0021∗PFSC + 0.0055)). Conclusion: Sonoclot® is useful to evaluate coagulation function in pediatric patients who undergo CPB. Preventive administration of FFP or PC in CPB circuit could reduce bleeding after CPB.

Influence of Respiratory Gas Density on Tidal Volume during Mechanical Ventilation: A Laboratory Investigation and Observational Study in Children.

Fluid mechanics show that high-density gases need more energy while flowing through a tube. Thus, high-density anesthetic gases consume more energy to flow and less energy for lung inflation during general anesthesia. However, its impact has not been studied. Therefore, this study aimed to investigate the effects of high-density anesthetic gases on tidal volume in laboratory and clinical settings. In the laboratory study, a test lung was ventilated at the same pressure-controlled ventilation with 22 different gas compositions (density range, 1.22-2.27 kg/m3) using an anesthesia machine. A pneumotachometer was used to record the tidal volume of the test lung and the respiratory gas composition; it showed that the tidal volume of the test lung decreased as the respiratory gas density increased. In the clinical study, the change in tidal volume per body weight, accompanied by gas composition change (2% sevoflurane in oxygen and with 0-30-60% of N2O), was recorded in 30 pediatric patients. The median tidal volume per body weight decreased by 10% when the respiratory gas density increased from 1.41 kg/m3 to 1.70 kg/m3, indicating a significant between-group difference (P < 0.0001). In both settings, an increase in respiratory gas density decreased the tidal volume during pressure-controlled ventilation, which could be explained by the fluid dynamics theory. This study clarified the detailed mechanism of high-density anesthetic gas reduced the tidal volume during mechanical ventilation and revealed that this phenomenon occurs during pediatric anesthesia, which facilitates further understanding of the mechanics of ventilation during anesthesia practice and respiratory physiology.

Superiority of OxyMaskTM with less carbon dioxide rebreathing in children.

Despite the growing importance of oxygen-delivery devices worldwide, there are only a few reports of physiological data on various oxygen masks in children. The possibility of carbon dioxide (CO2) rebreathing has been a prevalent concern with the use of oxygen-delivery devices. OxyMask KidTM (Southmedic Inc. Canada; hereafter OxyMask) is expected to reduce CO2 rebreathing even at low oxygen flow rates because of its structural features. Biological data using OxyMask in children have not been well investigated. Measured respiratory parameters of OxyMask with those of a simple oxygen mask in healthy children were compared. Ten subjects were enrolled, with a median age of 5.4 years. All subjects used both OxyMask and a simple oxygen mask. The fraction of inspiratory oxygen (FIO2), partial pressure of inspiratory CO2 (PICO2), and partial pressure of end-tidal CO2 were measured using a sidestream gas-sampling monitor in all subjects. The oxygen flow rate was set at 1, 3, 5, and 10 L/min. FIO2 levels were higher with OxyMask than those with the simple oxygen mask at 3 L/min of oxygen. PICO2 levels were significantly lower with OxyMask than those with the simple oxygen mask (1.5 mmHg vs. 3.7 mmHg at 1 L/min, P = 0.005; 1.0 mmHg vs. 2.7 mmHg at 3 L/min, P = 0.005, respectively), whereas PICO2 levels were higher at low oxygen flow rates with both masks.Conclusion: Our results showed that higher FIO2 and less CO2 rebreathing were achieved with OxyMask than those with a simple oxygen mask at low flow rates of oxygen in healthy children. What is Known: • OxyMask is expected to reduce carbon dioxide rebreathing even at low oxygen flow rates because of its structural features. • Efficacy has been demonstrated in experimental models and adult data, but clinical data on the use of the OxyMask in children are limited. What is New: • Higher fraction of inspiratory oxygen and lesser carbon dioxide rebreathing were achieved with OxyMask than with a simple oxygen mask at low flow rates of oxygen in healthy children.

Successful management of an infant with hypertensive heart failure associated with Wilms' tumor: a case report.

BACKGROUND: Wilms' tumor with hyperreninemia may result in critical cardiovascular decompensation. We report a case of severe hypertensive heart failure followed by tumor resection in a 3-month-old infant with Wilms' tumor. CASE PRESENTATION: A 3-month-old girl was admitted to the intensive care unit for Wilms' tumor with hypertension and hypoxia. Her systolic blood pressure was 110 mmHg, and her SpO2 was 92%. She presented with severe hypertensive heart failure and received mechanical ventilation and antihypertensive therapy for hypertension and heart failure. An alpha 2-adrenergic receptor agonist was used for sedation as part of her antihypertensive therapy. On hospital day 16, nephrectomy with tumor resection was performed under general anesthesia. Her systolic blood pressure did not vary more than 20 mmHg during surgery due to appropriate preoperative management. Hemodynamic collapse did not occur. CONCLUSIONS: The highlight of this case report is the successful management of an infant with Wilms' tumor, particularly with respect to preoperative hemodynamic control and sedation.

[Case of drug-induced angioedema (DIAE) on induction of anesthesia with difficult ventilation due to oropharyngeal edema].

A 69-year-old man with a past history of hypertension on angiotensin II receptor blocker (ARB) for three months presented for radical prostatectomy. Immediately after induction of anesthesia with fentanyl and propofol, mask ventilation became difficult, although no significant hemodynamic changes occurred. Fiberoptic examination revealed severe oropharyngeal edema, but, the trachea was successfully intubated. Afterward, the operation proceeded without complications. He stayed in the ICU for 4 days until the trachea was extubated successfully. He was diagnosed with DIAE because of his history of dyspnea with exclusion of other possible pathophysiological conditions.

[Anesthetic management for a case of an isolated congenital unilateral absence of the right pulmonary artery].

Isolated unilateral absence of the right pulmonary artery without any intracardiac anomaly (APA) is a rare congenital cardiovascular disorder. We report a case of a 47-day-old female infant with right APA who underwent pulmonary angiogram under general anesthesia. Induction and maintenance of anesthesia consisted of total intravenous anesthesia with propofol, remifentanil and vecuronium. Hemodynamic status and oxygenation were stable throughout the examination. Mean pulmonary artery pressure was 22 mmHg. During bronchofiberscopic examination through an endotracheal tube, SpO2 rapidly decreased from 98% to 50% in 10 s despite sufficient preoxygenation with 100% oxygen. Our case suggests that a care must be taken for desaturation during procedures without ventilation in PAP patients.

[Effect of dexmedetomidine on hemodynamics in pediatric patients following cardiac surgery].

BACKGROUND: Dexmedetomidine (DEX), a highly selective alpha2-adrenergic receptor agonist, has sedative and analgesic properties with minimal respiratory depression. We retrospectively evaluated the hemodynamic effects of dexmedetomidine in pediatric patients following cardiac surgery. METHODS: The subjects were twenty children aged 4 months to 15 years who had undergone cardiac surgery. After hemodynamics were stabilized in ICU, DEX was infused at a rate of 0.3-0.5 microg x kg(-1) min(-1), following initial loading (0.5 microg x kg(-1) over 10 min). Heart rate and blood pressure were analyzed just before starting infusion, following 1, 3, 6 hours during infusion, and at the end of the infusion. RESULTS: There was no change in blood pressure during measurement. HR was slightly decreased during DEX infusion but not significantly. After discontinuation of DEX, HR was significantly increased from 109 +/- 17 to 124 +/- 19 beats x min(-1) (mean +/- SD) (P < 0.05). Two patients were excluded from the study, because clinically significant bradycardia developed during DEX infusion. CONCLUSIONS: DEX had little effect on blood pressure in patients after cardiac surgery. DEX, however, had a tendency to decrease HR. Therefore, it shoud be used with caution in patients with low heart rate.

[Sevoflurane anesthesia for pancreatectomy in an infant with nesidioblastosis].

We report a case of nesidioblastosis, which is characterized by hyperinsulinism due to a diffuse increase in the number of beta-cells in the pancreas and, consequently, severe hypoglycemia. The patient was a 79-day-old boy. He had been suffering from severe hypoglycemia despite aggressive treatment, including glucose loading and administration of glucocorticoid and diazoxide. Pancreatectomy was performed. Anesthesia was induced by thiamilal 25 mg and vecronium and was maintained by 1 to 2% sevoflurane in 65% nitrous oxide and fentanyl 5 micrograms. No hemodynamic instability was observed during anesthesia. Blood glucose level was maintained around 200 mg.dl-1 without any hyperglycemic event by continuous infusion of 20% glucose at the rate of 14.5 mg.kg-1.min-1, which was calculated from the daily glucose demand to prevent hypoglycemia preoperatively.

[Differential lung ventilation by use of a combination of a laryngeal mask airway and an endotracheal tube in a pediatric patient with atelectasis of the right lung].

A 5-month-old boy was diagnosed as having complete atelectasis of the right lung due to RS virus infection at the age of 1 month. Conventional respiratory physical therapy, inhalation therapy and mechanical ventilation through an endotracheal tube failed to re-expand the right lung, while the left lung gradually became overinflated. We therefore tried differential lung ventilation by using a combination of a laryngeal mask airway and an extra long endotracheal tube (ID, 3.5 mm; length, 280 mm; Portex Pediatric Tracheal Tube, Extra length; SIMS Portex Co., Ltd. UK). Following induction of anesthesia, a laryngeal mask airway #2 was inserted. Then, an extra long endotracheal tube was inserted through the laryngeal mask airway and was guided to the right main bronchus with the aid of a fiberscope. The right lung was selectively lavaged and inflated with high pressure while ventilation was maintained through the laryngeal mask airway. The SpO2 value was maintained at more than 95% throughout the procedure despite some leakage from the ventilation system. The case demonstrates that differential lung ventilation by use of a combination of a laryngeal mask airway and extra long endotracheal tube is useful for the treatment of a pediatric patient with severe atelectasis.

[Obstetrical anesthesia for parturient patients with HELLP syndrome].

In the period from April 1995 to March 2000, 11 parturient patients were diagnosed as having HELLP syndrome and underwent Caesarian section at our institution. All of the patients also had eclampsia or preeclampsia. Six of the operations were performed under general anesthesia and 5 were performed under regional anesthesia (one epidural and 4 spinal blocks). Subarachnoid anesthesia was well tolerated and clinically serious decreases in blood pressure with onset of block were not common. In the cases in which general anesthesia was used, control of blood pressure was difficult and the Apgar scores of the babies were low. No major complications occurred during the postoperative periods. Anesthetic management of a parturient patient with HELLP syndrome is modeled on the underlying preeclamptic condition. Determination of the appropriate anesthetic should be based on the patient's condition, condition of the fetus, and the urgency of the situation.

Epidural anesthesia affects pulse oximeter readings and response time.

We investigated the effects of epidural anesthesia on pulse oximeter readings (Spo2) and response time because this type of anesthesia causes significant changes in microcirculation at measurement sites. Twenty patients were divided into lumbar epidural (L-EPI;n=10) and the cervical epidural (C-EPI;n=10) groups. Spo2 and skin blood flow (SBF) were measured at the finger and toe simultaneously by pulse oximeter and laser Doppler flowmeter, respectively. Data were collected before and after epidural anesthesia for 1 min and the response time was calculated by the difference between the finger and toe using the breath-holding method. Epidural anesthesia increased SBF in the blocked area and decreased it in the nonblocked area in both groups (P<0.01, respectively). In the L-EPI group, Spo2 was increased at the finger (P<0.05) and decreased at the toe (P<0.05). In the C-EPI group, Spo2 at both the finger and toe was decreased by the anesthesia. ΔSpo2 (Spo2 at the finger minus Spo2 at the toe) was increased in the L-EPI group (P<0.05) and decreased in the C-EPI group (P<0.01). The difference in the response time became larger in the C-EPI group and smaller or opposite in the L-EPI group after anesthesia. The difference in response time and SBF were significantly correlated (r=0.71;P<0.05). These results indicated that epidural anesthesia lowerd Spo2 and shortened the response time through vasodilation in the blocked area and caused the opposite reactions in the nonblocked area through compensatory vasoconstriction.