Alfonso Altamirano

Anticipation of the difficult airway: preoperative airway assessment, an educational and quality improvement tool

BACKGROUND Assessment of the potentially difficult airway (DA) is a critical aspect of resident education. We investigated the impact of a new assessment form on airway prediction and management by anaesthesia residents. We hypothesized that residents would demonstrate improvement in evaluation of DAs over the study duration. METHODS After IRB approval, anaesthesia residents were randomized into two groups: control (existing form) and experimental (new form). Data were collected prospectively from August 2008 to May 2010 on all non-obstetric adult patients undergoing non-emergent surgery. RESULTS Eight thousand three hundred and sixty-four independent preoperative assessments were collected and 8075 were analysed. The experimental group had the higher completion rate than the control group (94.3% vs 84.3%, P=0.001). DA prediction was higher for the control group (71.2%) compared with the experimental group (69.1%; P=0.032). A significant improvement in prediction rates was found over time for the experimental group (likelihood estimate=0.00068, P=0.031). CONCLUSIONS The use of a comprehensive airway assessment did not improve resident ability to predict a DA in an academic, tertiary-based hospital, anaesthesiology residency training programme.

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.

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.

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.

Post-Operative Effects: Comparison of Total Intravenous and Inhalational Anesthesia

Background: Propofol is an intravenous anesthetic with known antiemetic properties. Less confirmed are its potential analgesic or antinociceptive postoperative effects when used as a maintenance anesthetic during surgery. We compared the postoperative effects of total intravenous anesthesia (TIVA) with propofol to those of inhalational anesthesia with sevoflurane and looked for differences in the quality of recovery of patients. Methods: We studied 23 patients scheduled to undergo endoscopic sinus surgery (ESS). Using a doubleblind experimental method, we randomly assigned patients to receive either TIVA with propofol/remifentanil (PR) or inhalational anesthesia with sevoflurane/remifentanil (SR). We measured degree of pain (per visual analog scale where 1=no pain and 10=worst pain imaginable), incidence of nausea and vomiting, and duration of recovery postoperatively. Results: Mean pain rating was 3.4±3.3 in the PR group and 5.3±2.8 in the SR group. Median pain rating was 3±3 in the PR group and 5.5±1.5 in the SR group. In the PR group, 3 out of 12 patients reported a pain score > 4; In the SR group, 6 out of 10 patients reported a pain score > 4. Only 1 incidence of nausea was reported per group. Narcotics administered were comparable between both groups. Mean recovery time was 67±30 minutes in the PR group and 69±27 minutes in the SR group. Conclusion: We found no statistically significant difference between TIVA with propofol and inhalational anesthesia with sevoflurane as they relate to postoperative pain, nausea and vomiting, narcotic administration, and recovery time.

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 patients 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.

Utilization of C-MAC videolaryngoscopy for direct and indirect assisted endotracheal intubation

Background: The experiences of seasoned practitioners with the new C-MAC indirect videolaryngoscope system have shown promising results in the management of difficult airways. However, a comparison of direct and indirect laryngoscopy utilizing the C-MAC system as its own control has not been performed in a cohort of anesthesiologists-in-training. The primary aim was to compare direct and indirect laryngoscopy in terms of intubation time with secondary outcomes including laryngoscopy time and airway view with the same size 3 blade. Methods: The study was registered with www.clinicaltrials.gov (NCT01104090). Oral and written informed consent was obtained from 50 adult patients with BMI < 40 kg/m 2 who required general anesthesia for elective surgery with tracheal tube placement. The patients were randomized to two groups, each receiving two laryngoscopies, n=25 direct-first and n=25 indirect-first. Results: All patients except for one were successfully intubated on the first attempt. The intubation time was 12.3±11.1 sec immediately following videolaryngoscopy (direct laryngoscopy first group) and 9.8±7.1 sec immediately following direct laryngoscopy (videolaryngoscopy first group), p=0.35. The first laryngoscopy time was 8.7±4.7 sec in the direct group and 13.3±10.7 sec in the indirect group, p=0.06. Twenty-percent of direct first cases compared to 0% of indirect first cases showed an improvement in airway view score by at least two classes on the second laryngoscopy, p=0.02. Backward-upward-rightward pressure was used in 36% of direct first and 12% of indirect first patients, p=0.047. Conclusions: This study corroborates previous results on the use of the C-MAC videolaryngoscopy system during endotracheal-assisted intubation. Although there was no difference in intubation time between direct laryngoscopy and videolaryngoscopy, the C-MAC system was found to improve laryngeal views and reduce the number of necessary laryngeal manipulations. A larger randomized study utilizing a similar model is necessary to definitively determine significant clinical results. Trial registration: ClinicalTrials.gov NCT01104090.

Platelet Function as Affected by Total Intravenous and Inhalational Anesthesia

Background: Few studies have attempted to demonstrate a benefit of a total intraveneous anesthesia (TIVA) as the sole technique to optimize and reduce bleeding. Also few reports have linked the use of propofol to platelet dysfunction, and while Thromboelastography (TEG ® ) has been used previously, its complement platelet mapping (PM™) has not. The aim of the study was to exclude different causes for blood loss during surgery, including drug effects on platelet function. Methods: After IRB approval, we studied 23 patients scheduled to undergo endoscopic sinus surgery. Using a double-blind experimental method, we randomly assigned patients to receive either TIVA with propofol/remifentanil (PR) or inhalational anesthesia with sevoflurane/remifentanil (SR). Results: Estimated blood loss (PR 152.9 ± 161.3 cc/SR 355.9 ± 393.4 cc) showed no significant group difference. Platelet function was within the normal range for both groups, though several preoperative TEG ® parameters were statistically different between the two groups (PR values were greater than SR values for MA Activator, ADP MA, AA MA and ADP Aggregation; SR value was greater than PR value for ADP Inhibition). Several TEG® PM™ parameters had statistically significant differences pre- and postoperatively in the SR group (Postoperative were greater for ADP MA and ADP Aggregation; Preoperative value was greater for ADP Inhibition). Individual patient abnormalities were noted. Conclusion: The results do not indicate any significant difference between propofol and sevoflurane as concerns blood loss and platelet inhibition.

Anticipation of the Difficult Airway: Preoperative Airway Assessment, an Educational and Quality Improvement Tool

Careful airway assessment before anesthesia induction and perioperative airway management are critical responsibilities of the anesthetist. However, despite improvements in patient monitoring, airway devices, clinical protocols, and training, which have reduced the risk associated with an unpredicted difficult airway (DA), these changes have not reduced the incidence of unanticipated DAs in clinical practice. This prospective, randomized, single-blind study was undertaken to investigate the impact of a new assessment form on airway prediction and management by anesthesia residents, based on the hypothesis that residents would improve in their evaluation of DAs during the study. Adult nonobstetric patients undergoing elective surgery requiring general anesthesia were enrolled in the study if their airway was not already secured. Ninety-one residents were randomized to use the new comprehensive airway assessment form along with the existing form or the existing anesthesia preoperative assessment form only. The new form required a detailed assessment of the patient’s airway history and physical examination. Difficult mask ventilation was defined as difficulty in maintaining a mask seal and obtaining satisfactory capnography (end-tidal CO2 and tidal volume). Difficult supraglottic airway was defined as either inability to physically place a supraglottic device or inadequacy of ventilation, oxygenation, or airway protection after placement that required conversion to another technique. Difficult direct laryngoscopy was defined as difficulty in visualizing any portion of the vocal cords after conventional laryngoscopy requiring more than 1 attempt. Difficult intubation was defined as proper insertion of the tracheal tube with conventional laryngoscopy requiring multiple attempts. Difficult surgical airway was considered as a difficult cricothyrotomy or tracheostomy, open or percutaneous, performed electively or emergently, to manage a DA due to bleeding, poor orientation, and difficult instrumentation. The database included 9117 postoperative encounters, but the 155 patients who received multiple anesthetics were excluded from the analysis. All statistical analyses were performed using SAS 9.2 (SAS Institute, Cary, NC). P < 0.05 indicated statistical significance. Of the 83,645 preoperative assessments, 8075 assessments were included in the final analysis, with 3332 (41%) performed by the experimental group and 4743 performed by the control

An acute neurological syndrome with cerebrovascular and parkinsonian clinical features associated with perioperative SNRI withdrawal.

To JNA Readers: This is a report of a 40-year-old male with past medical history of fibromyalgia and degenerative disk disease, who underwent C5-C6 anterior cervical discectomy and fusion and emerged from anesthesia with strokelike symptoms. Preoperatively, he had no neurological deficits and the intraoperative course was uneventful. In the postanesthesia care unit, he was noted to have aphasia, right hemiplegia, and left-biased gaze deviation. Given the symptoms, the concern was for a CVA in the left MCA distribution. He had no movements in his right extremities despite noxious stimuli, and his left hand displayed a spontaneous pill-rolling type activity. Head CT and MRI failed to reveal any abnormalities. After extensive workup with no clear diagnosis, we decided to resume his home medications, which included milnacipran (50mg) twice daily, a serotonin-norepinephrine reuptake inhibitor (SNRI) that he was taking for fibromyalgia. After 2 doses, he started moving all of his extremities to command and the pill-rolling motion of his left hand disappeared. After 2 more doses, he regained full strength in all his extremities. Our patient was taking milnacipran daily for fibromyalgia for over 1 year. He discontinued it the night before surgery; about 30 hours had elapsed from his last dose to the time he presented with stroke-like symptoms. The most intriguing symptom he had was a pill-rolling motion of the left hand. After extensive literature search, we believe it may be related to the complex interactions that milnacipran has on the nigrostriatal pathway. A brief understanding behind the pathophysiology of Parkinson Disease (PD) may shed light on how this symptom was possible (Fig. 1). Keeping the pathophysiology of PD in mind, we researched the neuroendocrine effects of treatment with milnacipran on the central dopaminergic system. Rogoz and colleagues used spiperone, a selective D2 agonist, to study the effects of milnacipran use on binding kinetics at the D2 receptor. They concluded that milnacipran, administered repeatedly, increased binding affinity of spiperone to D2 receptors within 72 hours1 and further went on the say that repeated dosing with milnacipran increased the density and affinity of D2 receptors for their selective agonists. Both PD and chronic milnacipran use ultimately lead to hypersensitivity