The effects of the oxygen flow rate on heart rate variability in the PACU after TIVA

BACKGROUND: Oxygen increases the cardiac vagal tone, blood pressure, systemic vascular resistance and vascular tone in healthy adults.This study assessed the autonomic tone according to different oxygen flow rates via different types of masks with using the heart rate variability (HRV) in the PACU after total intravenous anesthesia (TIVA). METHODS: We prospectively studied 27 patients after TIVA in the PACU.The 5 L group received oxygen via a simple mask with an oxygen rate of 5 L/min and the 10 L group received oxygen via a mask with a reservoir bag at a rate of 10 L/min in the PACU. We evaluated the HRV at the point of stabilization before anesthesia (BL), 5 min in the PACU (PACU 5), 30 min in the PACU (PACU 30) and 60 min in the PACU (PACU 60). RESULTS: In the 5 L group, the nuHF was increased to 42.4 +/- 24.2 at 60 min in the PACU as compared with 27.1 +/- 19.1 at 5 min in the PACU.In the 5 L group, the LFHFr was decreased to 2.3 +/- 2.1 at PACU 60 as compared with 6.6 +/- 9.7 at PACU 5 and the nuLF was decreased to 56.9 +/- 23.2 at PACU 60 as compared with 72.9 +/- 19.0 at PACU 5.There were no significant changes between the two groups at PACU 5, PACU 30 and PACU 60.The oxygen saturation was increased at PACU 60 compared with PACU 5 in the two groups. CONCLUSIONS: These finding indicates that 1 h of oxygen administration with 5 L/min during emergence from anesthesia increased the relative vagal tone, and the arterial blood pressure is stable irrespective of the oxygen flow rate.

The dose-dependent effect of alfentanil on the rocuronium induced withdrawal in children

BACKGROUND: The injection of rocuronium causes pain and withdrawal responses.This study was designed to determine an optimal dose of alfentanil to prevent the withdrawal responses associated with injection of rocuronium in children. METHODS: One hundred and ten ASA physical status I and II pediatric patients were randomly allocated into four groups; Group C (control; normal saline 3 ml, n = 28), Group A5 (alfentanil 5microgram/kg, n = 28), Group A10 (alfentanil 10microgram/kg, n = 27) and Group A15 (alfentanil 15microgram/kg, n = 27). After the induction of anesthesia with 5 mg/kg of thiopental sodium, the test drug was injected over 20 seconds, respectively. After one minute, rocuronium 0.6 mg/kg was injected over 5 seconds. The patient's response after injection was graded using a four-point scale. Additionally, the mean arterial pressure and heart rate were recorded upon arrival in the operating room, as well as 1 min before and 1 min after tracheal intubation. RESULTS: The incidence of withdrawal responses was 96%, 61%, 19% and 19% in groups C, A5, A10 and A15, respectively. The incidence and severity of withdrawal responses in group A10 and A15 were lower than group C and A5. CONCLUSIONS: After thiopental injection, alfentanil 10microgram/kg prevent the withdrawal responses on injecting rocuronium in pediatric patients.

Effect of Different Doses of Rocuronium on Intubation and the Incidence of Acute Laryngeal Sequelae / 대한마취과학회지

BACKGROUND: In ambulatory surgery, which is of short duration, anesthesiologists often do not use a muscle relaxant, or any other induction technique which could facilitate muscle relaxation for endotracheal intubation.Incomplete muscle relaxation, however, results in vocal cord movement and the possibility of damage to the vocal cords and adjacent structure.The aim of this study was to evaluate the macroscopic sequelae of intubation on vocal cord and laryngeal structure and assess postoperative sore throat or hoarseness. METHODS: 100 patients with class I or II ASA physical status were enrolled in this study.It was divided into two groups, Group C (conventional intubation dose of rocuronium; 0.6 mg/kg) and group L (low intubation dose 0.45 mg/kg).Anesthesia was induced with 10microgram/kg of alfentanil and 2.0 mg/kg of propofol i.v.Intubation was performed 90 second after rocuronium injection and the intubation condition was checked.Macroscopic sequelae ofthe laryngeal structure were evaluated using a flexible fiberoptic bronchoscope. After completion of surgery, the patient was asked to report sore throat or hoarseness. RESULTS: Macroscopic sequelae, such as erythema or hemorrhage, were statistically different between the two groups.There were no cases of minimal hemorrhage of either vocal cords or of the arryepiglottic folds in group C whereas there were two cases in group L.There was no statistical difference in incidence and severityof sore throat or hoarseness between the two groups. CONCLUSIONS: Although there were more macroscopic effects in the vocal cords and aryepiglottic folds, a low intubation dose of rocuronium can be used during surgery of short duration without fear of any significant sore throat or hoarseness after surgery.