The effect of intermittent versus continuous bladder catheterization on labor duration and postpartum urinary retention and infection: a randomized trial.

STUDY OBJECTIVE: To assess the effect of intermittent versus continuous bladder catheterization on labor duration and local anesthetic consumption. DESIGN: Randomized, controlled, prospective, single-blind trial. SETTING: University-affiliated hospital. PATIENTS: 209 ASA physical status I and II, primiparous parturients who received patient-controlled epidural analgesia for labor. INTERVENTIONS: Patients were randomly allocated to either the intermittent bladder catheterization group (Group IC; n = 109) or the continuous catheterization group (Group CC; n = 100). MEASUREMENTS: Duration of the second stage of labor, dose of local anesthetics given, and primary outcomes were compared by group using the t-test for independent samples. Main secondary outcomes were postpartum urinary retention and rate of postpartum urinary tract infection (UTI; asymptomatic bacteruria). MAIN RESULTS: Duration of the second stage of labor was longer in Group CC than Group IC: 105 +/- 72 vs. 75 +/- 52 min (P = 0.002). This finding was associated with increased local anesthetic dose requirement in Group CC during both stages of labor (73 +/- 25 mL vs. 63 +/- 26 mL; P = 0.005). The rate of UTI was similar (30%) in both study groups. CONCLUSION: Intermittent bladder catheterization was associated with shorter second-stage labor and less local anesthetic, but the same frequency of postpartum urinary retention and UTI was seen with both catheterization groups.

Gastroesophageal regurgitation during anesthesia and controlled ventilation with six airway devices.

STUDY OBJECTIVE: To investigate the frequency of gastroesophageal regurgitation and respiratory mechanics during positive pressure ventilation using 5 supraglottic devices or an endotracheal tube (ETT). DESIGN: Prospective, randomized study. SETTING: Operating rooms in a university-affiliated hospital. PATIENTS: 180 ASA physical status I and II patients, aged 18 to 65 years old, who underwent elective orthopedic, minor vascular, peripheral plastic, or urologic surgery during general anesthesia. INTERVENTIONS: Patients were randomly allocated to one of 6 airway device groups (n = 30 each): (1) Cobra Perilaryngeal Airway; (2) Laryngeal Mask Airway (LMA) Classic; (3) LMA Fastrach; (4) LMA ProSeal; (5) laryngeal tube; and (6) ETT (SIMS Portex, Ltd, Hythe, Kent, UK). After insertion of the designated device, the lungs of each nonparalyzed patient were mechanically ventilated. MEASUREMENTS: Hypopharyngeal pH, peak inspiratory pressures, sealing pressures, and lung compliance were measured. Hypopharyngeal pH lower than 4 was considered a regurgitation event. MAIN RESULTS: Regurgitation (episodes of pH <4) occurred in between one and 5 patients of each study group, with no statistical difference. Sealing pressures were similar among all the airway device groups. CONCLUSIONS: The frequency of gastroesophageal regurgitation in anesthetized, unparalyzed, mechanically ventilated patients was similar in patients whose lungs were ventilated with either the Cobra Perilaryngeal Airway, LMA Classic, Fastrach, ProSeal, laryngeal tube, or ETT.

Predistention of the epidural space before catheter insertion reduces the incidence of intravascular epidural catheter insertion.

BACKGROUND: Accidental cannulation of an epidural vein is a common complication associated with epidural anesthesia or analgesia. On the basis of a pilot study and previous reports, we tested the hypothesis that predistention of the epidural space with saline before epidural catheterization would ease catheter insertion and decrease the incidence of this complication. METHODS: Two-hundred-three laboring women were randomly assigned to receive an epidural with loss of resistance technique with 2 mL (nondistention) or 5 mL saline (distention). In the distention group, the syringe plunger was held closed before epidural catheter insertion. Then in both groups, a test dose of 3 mL of 1.5% lidocaine was injected through the epidural catheter. RESULTS: There were fewer accidental intravascular catheter placements (2% vs 16%, P = 0.0001) in the distention group, and 91% of patients in this group did not have any unblocked segments versus 67% in the nondistension group (P = 0.0001). The difference in onset time of analgesia was small (5.0 +/- 2 min vs 6 +/- 3 min, P = 0.0001) and not clinically important. The quality of analgesia (visual analog scores and ropivacaine consumption) was similar between groups. CONCLUSIONS: Distention of the epidural space with 5 mL saline before epidural catheter insertion decreased the incidence of accidental venous cannulation and the number of unblocked segments.

Proper insertion depth of endotracheal tubes in adults by topographic landmarks measurements.

STUDY OBJECTIVE: To evaluate a new method of endotracheal tube (ETT) positioning relative to carina, based on external topographic landmarks. DESIGN: Prospective, randomized, crossover study. SETTING: Operating room, university hospital. PATIENTS: 200 American Society of Anesthesiologists (ASA) physical status I-II patients (100 women and 100 men) scheduled for elective surgery with general anesthesia. INTERVENTIONS: ETT insertion depth was topographically determined by adding the distance measured (in cm) from the right mouth corner to right mandibular angle to the distance measured from the right mandibular angle to a point situated on the center of a line running transversally through the middle of the sternal manubrium. This method was compared to the 21/23 cm insertion depth method. MEASUREMENTS: ETT position was assessed fiberoptically. The main end point was considered the percentage of ETT tips situated more than 25% higher or lower than a predetermined "best" tip position (4 cm above the carina). MAIN RESULTS: There were 58.5% ETT tips positioned too closely (<3 cm above the carina) to the carina with the control method and 24% with the study method (P=0.0001). No ETT tip was too high (>5 cm above the carina). The tip-carina distance was shorter in women (2.7+/-2.5 vs 3.6+/-2.2 cm in men P=0.0001) and in those aged more than 65 years (2.8+/-2.4 vs 3.4+/-2.4 cm with age less than 65 years; P=0.012) only with the 21/23 cm method. CONCLUSIONS: With our new ETT positioning method, there were fewer ETTs positioned outside the desired range of distance to carina. Our method may be especially valuable in women and in patients older than 65 years.

Use of the Rapiscope vs chest auscultation for detection of accidental bronchial intubation in non-obese patients undergoing laparoscopic cholecystectomy.

STUDY OBJECTIVE: Main stem bronchial intubation is not always detected by routine means and may occur more frequently during laparoscopic procedures. Tracheal tube positional changes in non-obese patients undergoing laparoscopic cholecystectomy were detected by either the Rapiscope (Cook Critical Care, Bloomington, Ind) or chest auscultation. DESIGN: Prospective, double-blind, crossover study. SETTING: University hospital. PATIENTS: Forty non-obese patients (BMI <28 kg.m(-2)), aged 18 to 80 years, American Society of Anesthesiologists risk class I-III, who underwent elective laparoscopic cholecystectomy were enrolled in this double-blind, prospective study. INTERVENTIONS: After endotracheal intubation by one anesthesiologist, two other anesthesiologists assessed the tracheal tube's positioning by either the Rapiscope or chest auscultation; the results of one anesthesiologist's measurement were concealed from the other. MEASUREMENTS: Assessments of the endotracheal tube tip's position were performed after intubation, head-down, and head-up positioning, after maximal abdominal insufflation and before extubation. At the same time points, Sp(O2), ET(CO2), and peak inspiratory pressures were also recorded. MAIN RESULTS: Postintubation Rapiscope assessment revealed normal tracheal positioning of the tube's tip in all patients. Changes in tube's position were subsequently detected by the Rapiscope in 16 patients. In 8 cases, the tip moved endobronchially. Half of the endobronchial intubations occurred after maximal abdominal insufflation and the other half after changing the table position from neutral to 30 degrees head-down. Chest auscultation detected bronchial intubation in two cases only (P = .01). There were 4 additional events of downward movements and 4 events of cephalad migration of the tube's tip identified by the Rapiscope only. ET(CO2), Sp(O2), and peak inspiratory pressures did not change in patients who did experience bronchial intubation. CONCLUSION: The Rapiscope detected significantly more events of endobronchial intubation as compared with chest auscultation; it could be considered useful during procedures where tracheal tube movements are potential.

Milrinone and nitric oxide: combined effect on pulmonary artery pressures after cardiopulmonary bypass in children.

OBJECTIVE: To investigate the effect of milrinone combined with nitric oxide (NO) on the pulmonary artery pressures (PAP) after cardiopulmonary bypass (CPB), for repair of congenital heart defects (CHD) in children. DESIGN: Prospective, randomized, double-blind study. SETTING: University affiliated community hospital. PARTICIPANTS: Ninety children with pulmonary hypertension and repair of CHD. INTERVENTIONS: After weaning from CPB, patients (30 in each group) received 3 drug regimens: group 1, nitric oxide (NO); group 2, a continuous infusion of milrinone; and group 3, a combination of the 2. Drugs were started after CPB and given for 20 minutes. MEASUREMENTS AND MAIN RESULTS: Pulmonary and systemic pressures, PaCO(2), SaO(2), and pH values were recorded before bypass, after weaning from CPB, 10 and 20 minutes after starting each regimen, and 10 minutes after the cessation of treatment. Mean systemic blood pressure was lower (p < 0.05) in the combined treatment group after discontinuation of the drugs. Although mean PAP values were lower in the combined group (p < 0.05), no difference was recorded with regard to pH, PaCO(2), and PaO(2). The ratio between pre- and post-treatment mean PAP was highest in group 3(1.26 +/- 0.5) and lowest in group 2 (0.99 +/- 0.3, p < 0.001). The mean PAP recorded after discontinuation of the drug was lower than the baseline value in groups 1 and 3 (p < 0.05). CONCLUSIONS: The combination of milrinone and NO produced a more pronounced decrease in PAP than milrinone alone.

Difficult laryngoscopy: incidence and predictors in patients undergoing coronary artery bypass surgery versus general surgery patients.

OBJECTIVE: Cardiac surgery patients might have a higher incidence of difficult laryngoscopy than the general population because of older age, dental problems, and obesity. The authors estimated the incidence and predictors of difficult laryngoscopy in coronary artery bypass surgery patients. DESIGN: Prospective, controlled study. SETTING: University setting. PARTICIPANTS: Patients undergoing coronary artery bypass or general surgery. INTERVENTIONS: Two hundred consecutive patients undergoing coronary artery bypass graft and 444 general surgery patients, all aged >40 years, were compared for the incidence and predictors of difficult laryngoscopy, defined as a grade III or IV view. MEASUREMENTS AND MAIN RESULTS: Predictors of difficult laryngoscopy were considered mouth opening <4 cm, limited cervical mobility, thyromental distance <6 cm, protruding or partially missing upper teeth, and Mallampati classes 3 and 4. More cases of difficult laryngoscopy were recorded in cardiac patients (10% v 5.2%, p <0.023). The cardiac patients were older, mostly men, and belonged to ASA III-IV risk classes. Mallampati classes 3 and 4 were more frequent in the control group. With univariate analysis, difficult laryngoscopy correlated with 7 variables: older age, ASA-IV risk class, protruding or partially missing upper teeth, limited mouth opening, limited neck movement, thyromental distance <6 cm, and diabetes mellitus. Multivariate analysis adjusted for propensity score identified older age (odds ratio = 1.05/yr, 95% confidence interval = 1.005-1.09, p < 0.03) and limited neck movement (odds ratio = 9.5, 95% confidence interval = 2.2-41, p < 0.003), but not cardiac surgery per se, as independent predictors of difficult laryngoscopy. CONCLUSIONS: Difficult laryngoscopy was more frequent in cardiac surgery patients (10% v 5.2%). Older age and limited neck movement, but not cardiac surgery per se, were independent predictors of difficult laryngoscopy.

The effect of high-frequency ventilation of the lungs on postbypass oxygenation: A comparison with other ventilation methods applied during cardiopulmonary bypass.

OBJECTIVE: To compare the effect of high-frequency ventilation versus other ventilation methods applied during cardiopulmonary bypass on postbypass oxygenation. DESIGN: Prospective, randomized study. SETTING: University hospital. PARTICIPANTS: Seventy-five patients undergoing coronary artery bypass graft surgery. INTERVENTIONS: Patients were allocated to 5 equal groups of different ventilation methods during bypass. Groups 1 and 2 received high-frequency, low-volume ventilation with 100% and 21% oxygen, respectively. Groups 3 and 4 received 5 cm H(2)O of continuous positive airway pressure (CPAP) with either 100% or 21% oxygen. Patients from group 5 were disconnected from the ventilator during the bypass period. MEASUREMENTS AND MAIN RESULTS: Spirometry data, blood gas analysis, oxygen saturation as measured by pulse oximetry, and end-tidal carbon dioxide were recorded 5 minutes before chest opening, 5 minutes before bypass, 5 minutes after bypass, 5 minutes after chest closure and 6, 12, 18, and 24 hours after surgery. There were no differences in compliance and mean airway pressures. Alveolar-to-arterial oxygen gradients increased, and PaO(2) decreased significantly (p < 0.05) in all groups 5 minutes after bypass and this trend continued in the postoperative period. Patients from group 3 had higher PaO(2) and lower alveolar-to-arterial oxygen gradients, 5 minutes after weaning from bypass (p < 0.05). Extubation times were similar in all groups. CONCLUSIONS: The alveolar-arterial oxygen gradient was lower, and the PaO(2) was higher 5 minutes after bypass in patients receiving CPAP (100% O(2)) as compared with those ventilated with high-frequency ventilation.

Removal of deadspace volume from arterial catheter: How muchis enough?

OBJECTIVE: To evaluate the amount of volume needed to be removed from arterial catheter systems to compensate for "deadspace" and to allow an accurate measurement of pH and hemoglobin (Hb). DESIGN: Twenty patients undergoing heart surgery were evaluated in a steady state after the induction of anesthesia before surgery. Six blood samples were removed from the arterial catheter, the total volume of which was 1.5 mL at 30-sec intervals and measured for pH and Hb. The first sample was then taken after removing 1.5 mL from the tubing. In subsequent samples, the volume removed before sampling increased by 0.5-mL intervals. All other samples were compared with sample number 6, in which 4 mL of volume were removed before measurements. RESULTS: The first three samples with volumes of 1.5, 2.0, and 2.5 mL before measurement were inaccurate compared with sample number 6 (p <.000), giving artificially low values for both pH and Hb. There was no significant difference between the values measured in sample numbers 4, 5, and 6 (3.0, 3.5, and 4.0 mL, respectively). CONCLUSION: The amount of volume needed to be removed before measurement from an arterial catheter system, the volume of which is 1.5 mL, is 3 mL to achieve accurate measurements of pH and Hb. Removal of less volume results in an artificially low measurement.