Flexible optical intubation via the Ambu Aura-i vs blind intubation via the single-use LMA Fastrach: a prospective randomized clinical trial.

STUDY OBJECTIVE: This study was designed to compare the Ambu Aura-i to the single-use LMA Fastrach regarding time to intubation, success rate, and airway morbidity in patients undergoing elective surgery requiring general anesthesia. DESIGN: Prospective, randomized controlled trial. SETTING: Academic medical center. PATIENTS: Sixty-five adult patients scheduled for elective surgery requiring general anesthesia. INTERVENTIONS: Patients were randomized into 2 groups. Group A (n=33) were intubated using Ambu Aura-i and the Ambu aScope 2, a disposable flexible intubating scope, whereas those in group B (n=33) were blindly intubated using the Intubating Laryngeal Mask Airway (ILMA). MEASUREMENTS: First-attempt intubation success rate, overall intubation success rate, time to intubation, incidence of airway morbidity. MAIN RESULTS: The data demonstrated that time for endotracheal intubation in the ILMA group was significantly shorter than in the Ambu Aura-i group (P<.05). There was no difference in the first-attempt intubation success rate (Aura-i=26/33, 78.8%; ILMA=27/33, 81.8%; P=.757) or the overall intubation success rate (Aura-i=29/33, 87.9%; ILMA=31/33, 93.9%; P=.392) between the groups. Four patients (12%) in the Ambu Aura-i group had a failed intubation; 1 was due to a failure of the aScope monitor, whereas 3 were due to inability to visualize the glottis. Two patients (7%) in the ILMA group had a failed intubation due to esophageal intubation. There was no statistically significant difference in airway morbidity between the 2 groups. CONCLUSIONS: The data suggest that intubation with the ILMA is faster but that first-attempt and overall intubation success rates were comparable in both groups. The results suggest that although the flexible intubating scope-guided Aura-i does not outperform blind intubation via the ILMA, the technique is comparable in terms of first-attempt and overall intubation success rate.

Evaluation of Waste Anesthetic Gas in the Postanesthesia Care Unit within the Patient Breathing Zone.

Potential health hazards from waste anesthetic gases (WAGs) have been a concern since the introduction of inhalational anesthetics into clinical practice. The potential to exceed recommended exposure levels (RELs) in the postanesthesia care unit (PACU) exists. The aim of this pilot study was to assess sevoflurane WAG levels while accounting for factors that affect inhalational anesthetic elimination. In this pilot study, 20 adult day surgery patients were enrolled with anesthesia maintained with sevoflurane. Following extubation, exhaled WAG from the patient breathing zone was measured 8 inches from the patient's mouth in the PACU. Maximum sevoflurane WAG levels in the patient breathing zone exceeded National Institute for Occupational Safety and Health (NIOSH) RELs for every 5-minute time interval measured during PACU Phase I. Observed WAGs in our study were explained by inhalational anesthetic pharmacokinetics. Further analysis suggests that the rate of washout of sevoflurane was dependent on the duration of anesthetic exposure. This study demonstrated that clinically relevant inhalational anesthetic concentrations result in sevoflurane WAG levels that exceed current RELs. Evaluating peak and cumulative sevoflurane WAG levels in the breathing zone of PACU Phase I and Phase II providers is warranted to quantify the extent and duration of exposure.

Perioperative assessment of platelet function by Thromboelastograph Platelet Mapping in cardiovascular patients undergoing non-cardiac surgery.

UNLABELLED: Five percent of patients on dual antiplatelet therapy after coronary artery stent implantation will need non-cardiac surgery within the first year of therapy, and many more will need surgery later on. A function assay that evaluates platelet reactivity and inhibition by drug therapy is beneficial for such patients. Platelet Mapping assay (PM) using the TEG analyzer was tested in surgical patients. After IRB approval, 60 patients on combined aspirin and clopidogrel therapy were consented and enrolled. The TEG maximal amplitude (MA) and the percentage (%) platelet inhibition were recorded and analyzed. Fifty-seven patients (mean age 65.7 ± 10.9 years) had preoperative data only. Distribution of preoperative ADP (43.6 ± 24.4%) and AA inhibition (52.8 ± 30.2%) was determined, as well as for the preoperative MA ADP (43.1 ± 15.9 mm) and MA AA (37.2 ± 19.6 mm), showing an offset of the effect of both medications starting from day 3. Patients with complete pre- and postoperative data were stratified depending on duration off antiplatelet therapy (≤3 days, 3-7 days and >7 days): n = 27, ADP % preop inhibition (43.2 ± 21.6%), ADP % postop inhibition (32.3 ± 18.3%), p = 0.048. Distribution of immediate pre- and post- ADP and AA % inhibitions, showing a possible reduction in Δ of inhibition for clopidogrel at 3 days, were also assessed. CONCLUSION: According to the findings, the TEG PM assay might be a feasible approach to objectively evaluate the effects of aspirin and clopidogrel during the perioperative period and potentially guide drug management.

Pilot study comparing total intravenous anesthesia to inhalational anesthesia in endoscopic sinus surgery: novel approach of blood flow quantification.

OBJECTIVES: We compared anesthesia with sevoflurane-remifentanil hydrochloride (SR) to total intravenous anesthesia with propofol-remifentanil hydrochloride (PR) in patients undergoing endoscopic sinus surgery for chronic rhinosinusitis in terms of sinonasal mucosal blood flow, the surgical field visualization score, and blood loss. METHODS: We performed a double-blinded prospective study at a tertiary care center in 23 adults scheduled to undergo endoscopic sinus surgery for chronic rhinosinusitis. The patients were randomized to receive SR or PR. The sinonasal mucosal blood flow was measured by optical rhinometry. The surgical field visualization score was based on the Boezaart scale. RESULTS: The groups had similar clinical characteristics. During the 60- to 90-minute and 90- to 120-minute operative time windows, the blood flow was significantly greater in the PR group than in the SR group (p = 0.04 and p = 0.03, respectively). The amounts of blood loss in the PR and SR groups were 152.9 +/- 161.3 mL and 355.9 +/- 393.4 mL, respectively (p = 0.12). The median ratios of the surgical field visualization score to the number of sinuses operated on in the PR and SR groups were 2.1 and 1.8, respectively (p = 0.52). CONCLUSIONS: The intraoperative blood flow, as determined by optical rhinometry, was significantly greater with anesthesia with PR than with anesthesia with SR, 1 hour into the procedure; however, this difference did not translate into differences in the amounts of operative blood loss or in the surgical field visualization scores.

Endotrol-tracheal tube assisted endotracheal intubation during video laryngoscopy.

Video laryngoscopes allow indirect visualization of the glottis and provide superior views of the glottis compared to direct laryngoscopes in patients with both normal and difficult airways, but it may be difficult to advance the endotracheal tube (ETT) through the vocal cords into the trachea, unless a stylet is used. We propose that the Endotrol(®) ETT may be an effective tool to facilitate video laryngoscope-assisted orotracheal intubation without the use of a stylet. After obtaining written and oral informed consent, 60-adult patients scheduled for elective surgery requiring general anesthesia with orotracheal intubation were enrolled. Patients were randomized, respectively, to 1 of 4 groups: Group A(1), (15 patients): McGrath(®) with Endotrol(®) ETT; Group A(2), (15 patients): McGrath(®) with GlideRite(®)-styletted standard ETT; Group B(1), (15 patients): GlideScope(®) with Endotrol(®) ETT; Group B(2), (15 patients): GlideScope(®) with GlideRite(®)-styletted standard ETT. Statistical analysis was performed with Stata (Stata Corp v10, College Station). Mean time to intubation was longer in the Endotrol(®) groups compared to the GlideRite(®) groups: 60.1 (31.6) vs. 44.4 (27.6) s (p < 0.05). It was subjectively more difficult to intubate using the Endotrol(®) than with a GlideRite(®)-styletted ETT (difficulty score median [range] 2 [1-5] vs. 1 [1-3], respectively). Three intubations using the Endotrol(®) were characterized as difficult, whereas there were no difficult intubations with the GlideRite(®)stylet. The Endotrol(®) ETT, as compared to a standard ETT with a non-malleable stylet, is associated with longer intubation times and a subjective increase in difficulty of use. It may, however, still be a clinically viable alternative in video laryngoscope-assisted orotracheal intubation when use of a rigid stylet is undesirable.

Preoperative use of incentive spirometry does not affect postoperative lung function in bariatric surgery.

Morbidly obese patients undergoing general anesthesia for laparoscopic bariatric surgery are considered at increased risk of a postoperative decrease in lung function. The purpose of this study was to determine whether a systematic use of incentive spirometry (IS) prior to surgery could help patients to preserve their respiratory function better in the postoperative period. Forty-one morbidly obese (body mass index [BMI] > 40 kg/m²) candidates for laparoscopic bariatric surgery were consented in the study. All patients were taught how to use an incentive spirometer but then were randomized blindly into 2 groups. The control group was instructed to use the incentive spirometer for 3 breaths, once per day. The treatment group was requested to use the incentive spirometer for 10 breaths, 5 times per day. Twenty experimental (mean BMI of 48.9 ± 5.67 kg/m²) and 21 control patients (mean BMI of 48.3 ± 6.96 kg/m²) were studied. The initial mean inspiratory capacity (IC) was 2155 ± 650.08 (SD) cc and 2171 ± 762.98 cc in the experimental and control groups, respectively. On the day of surgery, the mean IC was 2275 ± 777.56 cc versus 2254.76 ± 808.84 cc, respectively. On postoperative day 1, both groups experienced a significant drop of their IC, with volumes of 1458 ± 613.87 cc (t test P < 0.001) and 1557.89 ± 814.67 cc (t test P < 0.010), respectively. Our results suggest that preoperative use of the IS does not lead to significant improvements of inspiratory capacity and that it is a not a useful resource to prevent postoperative decrease in lung function.

Impact of ovarian hormones on the modulation of the serotonin transporter by fluvoxamine.

Most preclinical studies examining the mechanism(s) of action of antidepressants are carried out using male animals. Blockade of serotonin transporter (SERT) function by selective serotonin reuptake inhibitors (SSRIs) is the initial event that triggers a not completely understood process that results in clinical improvement in depression. To investigate whether there are differences in the ability of SSRIs to inhibit the SERT between male and female rats at different phases of the estrous cycle, clearance of locally applied serotonin (5-HT) was measured by in vivo chronoamperometry. Local application of the SSRI, fluvoxamine, directly into the CA3 area of hippocampus increased significantly 5-HT clearance time parameters in male rats and female rats in estrus or diestrus, but not in proestrus. The contribution of ovarian steroids to this result was investigated in ovariectomized (OVX) rats treated with estradiol benzoate (EB) and/or progesterone (P). In OVX-control rats, fluvoxamine increased clearance time parameters, whereas EB and/or P treatment blocked this effect, consistent with what was seen in female rats in proestrus. This effect was gender-specific, since treatment of castrated rats with EB/P had no effect on the ability of fluvoxamine to slow 5-HT clearance. The time course of hormonal effects showed that 1-60 min after local application of 17-beta-estradiol (E(2)) into the CA3 region of OVX rats, fluvoxamine had no effect on clearance time of 5-HT. E(2)-BSA mimicked E(2)'s effects at 10 min but not at 60 min. Pretreatment with estrogen receptor antagonists blocked the effects of E(2). The finding that acutely both estradiol and progesterone can inhibit the ability of an SSRI to slow the clearance of 5-HT, may have important implications for the use of SSRIs in women.

A comparison of the chronic treatment effects of venlafaxine and other antidepressants on serotonin and norepinephrine transporters.

BACKGROUND: Venlafaxine blocks both serotonin and norepinephrine transporters (SERT and NET), with higher affinity for SERT. Serotonergic effects occur with lower doses, whereas both serotonergic and noradrenergic effects occur with higher doses of venlafaxine. Chronic treatment of rats with selective serotonin reuptake inhibitors decreases SERT binding sites, whereas similar treatment with selective norepinephrine reuptake inhibitors decreases NET binding sites. We hypothesized that venlafaxine would affect monoamine transporters dose-dependently, with low doses causing selective reduction of SERT binding sites and higher doses reducing both SERT and NET binding sites. METHODS: Rats were treated for 21 days with a low (15 mg/kg/day) or high (70 mg/kg/day) dose of venlafaxine, vehicle, or other antidepressants. The SERT and NET density was determined by quantitative autoradiography. RESULTS: Neither dose of venlafaxine nor amitriptyline reduced binding to either the SERT or NET. In rats with noradrenergic terminals destroyed by 6-hydroxydopamine, venlafaxine still failed to reduce SERT binding. Also, rats treated simultaneously with sertraline plus desipramine exhibited reductions in both SERT and NET binding. CONCLUSIONS: Chronic venlafaxine treatment affected SERT and NET binding differently from paroxetine or desipramine. The inability of venlafaxine to reduce SERT or NET binding sites is not due to its dual uptake inhibiting properties.

Regulation of the norepinephrine transporter by chronic administration of antidepressants.

BACKGROUND: Downregulation of serotonin transporter was observed previously after chronic treatment with selective serotonin reuptake inhibitors (SSRIs) but not selective norepinephrine reuptake inhibitors (NRIs). This study investigated if chronic treatment of rats with selective NRIs or SSRIs also affected the norepinephrine transporter (NET). METHODS: Rats were treated for 3 to 6 weeks by osmotic minipumps with either the selective NRIs, desipramine, or the SSRI paroxetine. RESULTS: [(3)H]nisoxetine binding sites as well as [(3)H]norepinephrine uptake were decreased in hippocampus and cortex after treatment with desipramine. By contrast, paroxetine-treated rats showed no alteration in either [(3)H]nisoxetine binding or [(3)H]norepinephrine uptake. NET messenger RNA levels in the locus coeruleus were unchanged by desipramine treatment. CONCLUSIONS: These results demonstrate that the marked decrease in NET density 1) is not a consequence of a decrease in gene expression; 2) was caused only by a selective NRI; and 3) was associated with a parallel decrease in norepinephrine uptake.