Effect of hypercapnia on pleth variability index during stable propofol: Remifentanil anesthesia

The pleth variability index [PVI], which is calculated from respiratory variations in the perfusion index [PI], has been shown to predict fluid responsiveness in mechanically ventilated patients; however, vasomotor tone changes induced by hypercapnia can affect PI and hence may slim down the accuracy of PVI. This study was designed to find out the impact of mild hypercapnia on PVI. A total of 30 patients were randomized after induction of general anesthesia with target controlled infusion propofol and remifentanil to either hypercapnia, [etCO[2] =45 mmHg], [group 1, 15 patients] or normocapnia [etCO[2] =35 mmHg] [group 2, 15 patients]. After a stabilization period of 10 min, patients were crossed over to the other intentional level of etCO[2]. Heart rate [HR], mean arterial pressure [MAP], PI, PVI were collected at the end of each stabilization period. Patient characteristics and baseline values of HR, MAP, PI and PVI were comparable between the groups. Carryover effect was statistically excluded. Hypercapnia significantly increased PI and decreased PVI with significant negative correlation. Hypercapnia retracts back PVI values compared with normocapnia. Precise judgment of fluid responsiveness as indicated by PVI necessitates its comparison against similar etCO[2] levels

Equal ratio ventilation [1:1] improves arterial oxygenation during laparoscopic bariatric surgery: a crossover study

Hypoxaemia and high peak airway pressure [Ppeak] are common anesthetic problems during laparoscopic bariatric surgery. Several publications have reported the successful improvement in arterial oxygenation using positive end expiratory pressure and alveolar recruitment maneuver, however, high peak airway pressure during laparoscopic bariatric surgery may limit the use of both techniques. This study was designed to determine whether equal I:E [inspiratory-to-expiratory] ratio ventilation [1:1] improves arterial oxygenation with parallel decrease in the Ppeak values. Thirty patients with a body mass index >/= 40 kg/m[2] scheduled for laparoscopic bariatric surgery were randomized, after creation of pneumoperitoneum, to receive I:E ratio either 1:1 [group 1, 15 patients] or 1:2 [group 2, 15 patients]. After a stabilization period of 30 min, patients were crossed over to the other studied I:E ratio. Ppeak, mean airway pressure [Pmean], dynamic compliance [Cdyn], arterial blood gases and hemodynamic data were collected at the end of each stabilization period. Ventilation with I: E ratio of 1:1 significantly increased partial pressure of O[2] in the arterial blood [PaO[2]], Pmean and Cdyn with concomitant significant decrease in Ppeak compared to ventilation with I: E ratio of 1:2. There were no statistical differences between the two groups regarding the mean arterial pressure, heart rate, respiratory rate, end tidal CO[2] or partial pressure of CO[2] in the arterial blood. Equal ratio ventilation [1:1] is an effective technique in increase PaO[2] during laparoscopic bariatric surgery. It increases Pmean and Cdyn while decreasing Ppeak without adverse respiratory or hemodynamic effects

Epidural analgesia during labor vs no analgesia: a comparative study

Epidural analgesia is claimed to result in prolonged labor. Previous studies have assessed epidural analgesia vs systemic opioids rather than to parturients receiving no analgesia. This study aimed to evaluate the effect of epidural analgesia on labor duration compared with parturients devoid of analgesia. One hundred sixty nulliparous women in spontaneous labor at full term with a singleton vertex presentation were assigned to the study. Parturients who request epidural analgesia were allocated in the epidural group, whereas those not enthusiastic to labor analgesia were allocated in the control group. Epidural analgesia was provided with 20 mL bolus 0.5% epidural lidocaine plus fentanyl and maintained at 10 mL for 1 h. Duration of the first and second stages of labor, number of parturients receiving oxytocin, maximal oxytocin dose required for each parturient, numbers of instrumental vaginal, vacuum-assisted, and cesarean deliveries and neonatal Apgar score were recorded. There was no statistical difference in the duration of the active-first and the second stages of labor, instrumental delivery, vacuum-assisted or cesarean delivery rates, the number of newborns with 1-min and 5-min Apgar scores less than 7 between both groups and number of parturients receiving oxytocin, however, the maximal oxytocin dose was significantly higher in the epidural group. Epidural analgesia by lidocaine [0.5%] and fentanyl does not prolong labor compared with parturients without analgesia; however, significant oxytocin augmentation is required during the epidural analgesia to keep up the aforementioned average labor duration