The Changes in Lung Mechanics before and after the Nuss Operation in Pectus Excavatum Patients / 대한마취과학회지

BACKGROUND: Nuss et al introduced a less invasive method for inserting a stainless steel bar through the small incision on the lateral chest wall into the pectus excavatum. This study was undertaken to assess the effect of the Nuss operation on lung mechanics, CT-Index and hemodynamics. METHODS: Twenty patients (age 4 to 17 years) with severe pectus excavatum underwent the Nuss operation. CT-Index (the internal transverse distance of the thorax/the vertebral-sternal distance at greatest depression) was evaluated before operation. Lung mechanics (dynamic compliance [Cdyn], static compliance [Cstat] and airway resistance [Raw]), hemodynamic changes (heart rate [HR], systolic blood pressure [SBP], and diastolic blood pressure [DBP]), and gas exchange (arterial oxygen tension [PaO2], arterial carbon dioxide tension [PaCO2], pulse oximeter saturation [SPO2] and end-tidal carbon dioxide tension[PETCO2]) were measured before and after the operation. RESULTS: Cdyn and Cstat decreased significantly (P < 0.05), but Raw did not change. PaCO2 and PETCO2 decreased significantly (P < 0.05), and SBP and DBP increased significantly (P < 0.05) postoperatively. CONCLUSIONS: It is concluded that decreased compliance after the Nuss operation may result from reduced thoracic elastance, not to a change of lung parenchyma.

Changes of Vital Signs, Expired Volume and Maximal Pressure by Mode of Ventilation during a Nuss Operation in Patients with Pectus Excavatum / 대한마취과학회지

BACKGROUND: This study was undertaken in order to investigate any cardiopulmonary changes caused by the surgical procedure during a Nuss operation in patients with pectus excavatum. METHODS: Thirty patients undergoing the Nuss operation were divided into two groups. The patients were randomly assigned to either Group-V (n = 15) which volume controlled ventilation was applied, or to Group-P (n = 15) where pressure controlled ventilation was applied. Mechanical ventilation provided a tidal volume to be set at approximately 10 ml/kg and a frequency set to keep ETCO2 in range, between 32 mmHg and 38 mmHg. During the surgical procedure, we recorded expired volume (VE) and inspired maximal pressure (Pmax) changes according to the ventilator mode, and then also recorded changes in vital signs. RESULTS: Heart rate and blood pressure had no significant changes in either groups. In Group-V, during rotation of the metal bar, there was a significant decrease in expired volume (P< 0.001), changes of inspired maximal pressure gradually increased with the operation (P< 0.001). In Group-P, rotation of the metal bar caused a significant decrease in expired volume (P< 0.001). CONCLUSIONS: During the Nuss operation, there should be careful observation of changes in the vital signs, expired volume and maximal pressure during insertion and rotation of the metal bar.

Comparison of Arterial and End-Tidal CO2 Tension by Position and Time Changes during Hip Replacement Arthroplasty in Elderly Patients / 대한마취과학회지

BACKGROUND: Hip replacement arthroplasty (HRA) is highly traumatic and performed in a lateral position for several hours and dead-space ventilation may increase. So, the difference between arterial and end-tidal PCO2 was investigated depending on the changes in the patient's posture during HRA in elderly patients. METHODS: Forty-three patients scheduled for a HRA were divided into two groups; Adult Group (n = 21, A-Group) and Elderly Group (n = 22, E-Group). Mean arterial pressure (MAP), heart rate (HR), PaO2, PaCO2, and end-tidal carbon dioxide tension (P(ET)CO2) were simultaneously measured at 10 min after anesthesia in a supine position (S[10]), at 30 min intervals from 30 min (L[30]) to 180 min (L[180]) in a lateral position and at 10 min in a supine position after the end of surgery (ES[10]) in both groups. The PaCO2-P(ET)CO2 gradient (P[a-ET]CO2) and dead space ventilation (Vd/ Vt) were calculated. RESULTS: At S(10), P(a-ET)CO2 in the A- and E-Groups was 7.0 +/- 5.0 and 7.2 +/- 3.3 mmHg respectively. From L(30) to ES(10), the P(a-ET)CO2 and the ratio of Vd/Vt in both groups increased significantly and progressively (P < 0.05 vs the control value) and the slope in the E-Group rose two times as compared to that in the A-Group. The correlation coefficient between P(a)CO2 and P(ET)CO2 was very significant from S(10) to L(90) and ES(10) in the A-Group, and from S(10) to L (60) in the E-Group (P < 0.01). CONCLUSIONS: For maintaining adequate ventilation of the elderly patient during HRA, PaCO2 should be measured intermittently along with the position changes after anesthesia in addition to the constant monitoring of PETCO2.

Right Ventricular Outflow Tract Reconstruction with Bovine Jugular Venous Valved Conduit / 대한흉부외과학회지

Homograft has been the conduit of choice in various types of congenital malformations which require right ventricular outflow tract reconstruction. However it has been proven to be less than ideal in young age group because of early failure of the conduite due to valve dysfunction and calcification. Furthermore limitation of availability of homograft particularly small sized conduits for neonates and infants is the most serious problem. A 19 month old female patient with pulmonary atresia and ventricular septal defect was operated on with a bovine jugular venous valved conduit as an alternative to the homograft for her right ventricular outflow tract reconstruction. Postoperative hemodynamic performance of the conduit was excellent without pressure gradient or valve regurgitation. With this early result bovine jugular venous valved conduit seems to be another excellent conduit because of good hemodynamics and size availability but long term follow up is necessary.

Effects of Etomidate, Propofol and Thiopental Sodium on Intraocular Pressure during the Induction of Anesthesia / 대한마취과학회지

BACKGROUND: During ophthalmologic surgery, a variety of anesthetic induction techniques are used in an attempt to prevent the rise of intraocular pressure (IOP). This study compared the effects of etomidate, a new intravenous anesthetic agent, on the changes in IOP with those of thiopental sodium and propofol. METHODS: Forty-five patients were randomly allocated and divided into three groups to be injected intravenously with etomidate 0.2-0.3 mg/kg (E-group, n = 15), propofol 2-3 mg/kg (P-group, n = 15) or thiopental sodium 4-5 mg/kg (T-group, n = 15). Systolic arterial pressure (SAP), heart rate (HR) and intraocular pressure (IOP) were measured at 1, 2 and 3 minutes after the administration of the induction agents. During the induction of anesthesia, the incidence of IV injection pain, myoclonus, hiccup and a decrease in SAP of more than 30% were investigated. RESULTS: At 1, 2 and 3 min following the induction of anesthesia, the SAP in the P-Group decreased significantly more than that in the other two groups (P < 0.05). After the induction, heart rate in the T-Group increased significantly more than that in the other two groups (P < 0.05). The three intravenous agents induced a significant decrease in IOP after an injection (P < 0.05). Comparing the three groups, the IOP in the E- and P-Group decreased significantly more than that in the T-Group (P < 0.05). CONCLUSIONS: Etomidate may be used as a choice of intravenous induction agent to reduce intraocular pressure in ophthalmologic operations especially in an emergency situation, geriatric and hypovolemic patients.

Influence of Decamethonium on the Neuromuscular Blocking Action of d-Tubocurarine in the Rat Phrenic Nerve Hemidiaphragm Preparation / 대한마취과학회지

BACKGROUND: To elucidate the mechanism of interaction between depolarizing and nondepolarizing muscle relaxants, train-of-four (TOF) fade during onset of neuromuscular blockade of d-tubocurarine (dTC) with or without decamethonium (C10) was evaluated in a rat phrenic nerve hemidiaphragm preparation. METHODS: Phrenic nerve hemidiaphragm preparations from 250~300 g Sprague Dawley rats (n=20) were suspended in a Krebs solution bubbled with 5% CO2 in O2 at 32oC. Phrenic nerves were stimulated with supramaximal stimuli of 0.2 ms duration at 0.15 Hz single twitch and 2 Hz TOF by a Grass S88 stimulator and the contractions of the hemidiaphragm were detected by a Grass FT03 force transducer then recorded. Estimation of ED50 for the dose response data were performed by a linear regression. The statistical significance of the results was determined by Wilcoxon Rank Sum test. p<0.05 was considered significant. RESULTS: Mean ED50 values of dTC and C10 calculated from the dose response relations were 7.76 microgram/ml and 0.65 microgram/ml respectively. Compared to adminstration of 2xED50 of dTC alone, TOF ratios at 75% and 50% of twitch height were markedly decreased by combination of ED50 of C10 and ED50 of dTC with statistic significance (67 +/- 1.9% vs. 46 +/- 3.1% and 36 +/- 2.5% vs. 7 +/- 2.5%). Conclusion: If fade in response to TOF stimulation represents a prejunctional effect, the results from this study suggests that the presynaptic action of C10 has some role in the mechanism of the interaction between dTC and C10 in the rat.