Right ventricular ejection fraction measurement in moderate acute respiratory failure (ARF). Effects of PEEP

Eight patients mechanically ventilated for acute respiratory failure were submitted to increasing levels of PEEP, from 0 to 15 cm H₂O. Right ventricular ejection fraction (RVEF) and end-diastolic volume index (RVEDVI) were measured using the fast response thermistor Swan-Ganz catheter. PEEP induced a linear decrease of cardiac index, while the pulmonary artery pressure increased. In three patients (group A) with a RVEDVI larger than 120 ml at ZEEP, RVEF decreased and RVEDVI increased with PEEP. In the other five patients (RVEDVI>120 ml, group B), RVEF was unchanged and RVEDVI decreased at PEEP 15 cm H₂O. This study suggest that RV changes induced by PEEP are probably a function of the initial RVEF and RVEDVI.     

Hemodynamic effects of levobupivacaine after pediatric caudal anesthesia evaluated by transesophageal doppler

Background: The aim of this study is to determine if there are significant differences in hemodynamic effects between combined general‐regional anesthesia using levobupivacaine 0.25% 2 ml·kg^?1 via the caudal route in comparison with balanced general anesthesia using continuous infusion of remifentanil in young children undergoing genitourinary surgery. Patients and methods: 62 ASA I‐II pediatric patients (12 female, 50 male) aged 6 months to 7 years undergoing genitourinary surgery were included in the study. Patients were randomly allocated into one of two groups of 31 patients each. Group Caud received caudal blockade with levobupivacaine 0.25% 2 mg·kg^?1 in combined general‐regional anesthesia and Group Gen received balanced general anesthesia with remifentanil. The noninvasive hemodynamic parameters were measured in each group 5 min after induction of general anesthesia or caudal block (Tcaud), after further 5 min coincident with skin incision (Tsi), 10 min after skin incision (T10i), at the end of surgical procedure (Tend). The time between Tcaud and Tsi was 10 min and the measurements during the interval time T10i‐Tend were performed every 15 min according to the duration of surgical procedures. Results: There was a decrease in all measured hemodynamic parameters at skin incision. The decreases occurred in both groups with those in the caudal group occurring at skin incision and those in the balanced anesthesia group occurring at 10 min after skin incision. These variations showed no significant differences for any of the stated outcomes; neither between the groups at each time point nor in the caudal in comparison with baseline measurements. Conclusions: Using transesophageal Doppler no differences in hemodynamic parameters could be detected between balanced general anesthesia with either caudal levobupivacaine or remifentanil infusion. Both techniques showed good hemodynamic stability with only minor changes from baseline over time which are unlikely to be of clinical significance except possibly in patients with preexisting cardiovascular compromise. Other studies with noninvasive monitoring in a larger population are required to better understand the consequences of caudal blockade on CO and on regional blood flow in infants.     

Effect of Propofol, Sevoflurane and Desflurane on systemic redox balance

We studied the effects of Propofol, Desflurane, and Sevoflurane on the systemic redox balance in patients undergoing laparohysterectomy. We measured blood concentration of glutathione (GSH), plasma antioxidant capacity (Trolox Equivalent Antioxidant Capacity-TEAC), and lipid peroxidation products (malondialdehyde (aMDA) and 4-hydroxynonenal (aHNE) protein adducts). Sixty patients were randomly placed into three groups of twenty people each. In Group P anesthesia was induced with Propofol 2 mg/kg and maintained with 12-10-8 mg/kg/min; in Groups S and D anesthesia was induced with 3 mg/kg Sodium Thiopental and maintained with 2 percent Sevoflurane and 6 percent Desflurane, respectively. Blood samples were collected prior to induction (T0 bas), 60min and 24h postoperatively (T1 60 and T2 24 h). In Group P, GSH increased on T1 60 and returned to baseline on T24h, while TEAC remained unmodified; in Groups S, GSH and TEAC decreased on T1 60 in Group D, on T1 60 there was a slight decrease of GSH and TEAC. The levels of aMDA slightly decreased throughout the study periods in Group P, increased in Group D, and remained stable in Group S. Propofol showed antioxidant properties, while Sevoflurane and Desflurane seemed to shift the redox balance towards oxidation, yet without inducing overt oxidative damage.