Jeff E. Mandel

A Randomized, Controlled, Double-Blind Trial of Patient-Controlled Sedation with Propofol/Remifentanil Versus Midazolam/Fentanyl for Colonoscopy

BACKGROUND:Patient-controlled sedation (PCS) with propofol has been advocated as a method for dealing with the narrow therapeutic window for moderate sedation, but previous studies have methodologic limitations. We hypothesized that, by using remifentanil in conjunction with propofol and using PCS in both arms of the study, we could demonstrate marked improvements in facility use compared with fentanyl plus midazolam. METHODS:Fifty patients undergoing elective colonoscopy were randomized (with concealed allocation) to midazolam/fentanyl (group MF) or propofol/remifentanil (group PR) administered via PCS. Time intervals for sedation and recovery, perceptions by patient, nurse, and gastroenterologist, and need for anesthesiologist intervention were assessed. RESULTS:Group PR patients were sedated and recovered significantly more rapidly than did group MF (P < 0.0001). In the group PR, recovery room time was actually shorter than procedure room time. Patient, nurse, and gastroenterologist perceptions were equivalent between the groups. Two patients in group PR required anesthesiologist intervention for arterial desaturation exceeding the primary safety end point. CONCLUSIONS:PCS with propofol/remifentanil yields superior facility throughput compared with midazolam/fentanyl when used in an appropriate care setting.

Efforts to enhance catheter stability improve atrial fibrillation ablation outcome

BACKGROUND Contemporary techniques to enhance anatomical detail and catheter contact during atrial fibrillation (AF) ablation include (1) the integration of preacquired tomographic reconstructions with electroanatomical mapping (3-dimensional image integration [I-EAM]), (2) the use of steerable introducers (SIs), and (3) high-frequency jet ventilation (HFJV). OBJECTIVE To prove that using these stabilizing techniques during AF ablation improves 1-year procedural outcome. METHODS We studied 300 patients undergoing AF ablation at our institution. Patients were divided into 3 equal treatment groups (100 patients each) on the basis of the tools utilized: (1) group 1: AF ablation performed without I-EAM, SI, or HFJV; (2) group 2: AF ablation performed using I-EAM and SI, but without HFJV; and (3) group 3: AF ablation performed with I-EAM, SI, and HFJV. The primary outcome was freedom from AF 1 year after a single ablation procedure. The burden of both acute and chronic pulmonary vein reconnection was also assessed. RESULTS Patients from groups 2 and 3 had significantly more nonparoxysmal AF (17% vs 30% vs 39%; P = .002), larger left atria (4.2 ± 0.8 cm vs 4.4 ± 0.7 cm vs 4.5 ± 0.8 cm; P<.001), and higher body mass index (BMI; 28.5 ± 5.8 kg/m² vs 29.1 ± 4.8 kg/m² vs 31.2 ± 5.4 kg/m²; P<.001). Despite these differences, with adoption of I-EAM, SI, and HFJV we noted a significant improvement in 1-year freedom from AF (52% vs 66% vs 74%; P = .006) as well as fewer acute (1.1 ± 1.2 vs 0.9 ± 1.1 vs 0.6 ± 0.9; P = .03) and chronic (3.5 ± 0.9 vs 3.2 ± 0.9 vs 2.4 ± 1.0; P = .02) pulmonary vein reconnections. CONCLUSIONS The incorporation of contemporary tools to enhance anatomical detail and ablation catheter stability significantly improved 1-year freedom from AF after ablation.

Quantitative airway analysis during drug-induced sleep endoscopy for evaluation of sleep apnea†‡

To quantitatively measure changes in airway caliber at multiple anatomical levels during drug‐induced sleep endoscopy (DISE) for evaluation of sleep apnea. We hypothesize that patients undergoing DISE will show: 1) collapse at multiple upper airway regions (retropalatal, retroglossal, and retroepiglottic), with greater collapse in the retropalatal region; and 2) greater anterior‐posterior dimensional narrowing than the lateral.

Anesthetic Management of Patients Undergoing Pulmonary Vein Isolation for Treatment of Atrial Fibrillation Using High-Frequency Jet Ventilation

OBJECTIVES The aim of this study was to describe anesthetic management and perioperative complications in patients undergoing pulmonary vein isolation for the treatment of atrial fibrillation under general anesthesia using high-frequency jet ventilation. The authors also identified variables associated with longer ablation times in this patient cohort. DESIGN A retrospective observational study. SETTING The electrophysiology laboratory in a major university hospital. PARTICIPANTS One hundred eighty-eight consecutive patients undergoing pulmonary vein isolation under general anesthesia with high-frequency jet ventilation. INTERVENTIONS High-frequency jet ventilation was used as the primary mode of ventilation under general anesthesia. MEASUREMENTS AND MAIN RESULTS High-frequency jet ventilation was performed successfully throughout the ablation procedure in 175 cases of the study cohort. The remaining 13 patients had to be converted to conventional positive-pressure ventilation because of high PaCO(2) or low PaO(2) on arterial blood gas measurements. Variables associated with a shorter ablation time included a higher ejection fraction (p = 0.04) and case volume performed by each electrophysiologist in the study group (p = 0.001). CONCLUSIONS High-frequency jet ventilation is generally a safe technique that can be used in catheter ablation treatment under general anesthesia.

A prospective, randomized, comparative trial evaluating respiratory depression during patient-controlled versus anesthesiologist-administered propofol-remifentanil sedation for elective colonoscopy

BACKGROUND Patient-controlled sedation (PCS) with propofol-remifentanil (PR) is associated with rapid sedation and recovery, but it is associated with a greater requirement for airway rescue than PCS with midazolam-fentanyl. OBJECTIVE To demonstrate that respiratory depression associated with PR is more frequent during anesthesiologist-administered sedation (AAS) than during PCS. DESIGN Prospective, randomized, open-label study. SETTING Academic medical center. PATIENTS Fifty patients undergoing elective colonoscopy. INTERVENTION PCS or AAS using PR. All patients breathed 100% oxygen via an anesthesia mask with continuous spirometry and bispectral index (BIS). MAIN OUTCOME MEASUREMENTS Respiratory rate and BIS. RESULTS Colonoscopy was completed in all patients. No patient under PCS required airway rescue. Five patients under AAS required bag-mask ventilation to resolve Sao(2) (arterial oxygen saturation) less than 90% lasting longer than 30 seconds. The median BIS for the AAS group was 71.7 (range 61.06-82.34) and 88.1 (range 83.15-93.05) for the PCS group. Median respiratory rates were 5.97 (range 1.21-10.73) breaths per minute for AAS and 13.19 (range 9.54-16.84) for PCS. Respiratory rates less than 2 breaths per minute composed 28% of the procedure time for AAS, but only 5% for PCS. Patients under PCS had lower median predicted effect site concentrations for PR, but were able to achieve brief peak levels exceeding those with AAS. These differences were significant (P < .001). LIMITATIONS Potential for bias with AAS. CONCLUSIONS Patients undergoing colonoscopy with PR are significantly more likely to require intervention for hypoventilation compared with PCS. ( CLINICAL TRIAL REGISTRATION NUMBER NCT00868920.).

Recent advances in patient-controlled sedation.

Purpose of review Advances in minimally invasive procedures have resulted in an increased demand for procedural sedation. Patient-controlled sedation (PCS) has been in clinical use for almost 20 years, but has not been reviewed in over 10 years. Recent findings Advances in microprocessor technology, increased demand for procedural sedation in a cost-conscious environment, and the availability of readily titratable pharmacologic agents together stimulated the development of alternative sedation practices. Continued research into the neurobiology of pain perception and the placebo effect has also played a role. PCS and patient-maintained sedation, primarily with propofol, have emerged as intriguing clinical alternatives to traditional sedation based in part on extensions of traditional PCA models. Summary PCS has been applied to a wide variety of procedures, but systems that can be applied ‘off-the-shelf’ are not easy to tune. New approaches to PCS may address these limitations. Better understanding of the psychology of sedation may lead to better patient acceptance of PCS.

Remifentanil–Midazolam Sedation Provides Hemodynamic Stability and Comfort During Epicardial Ablation of Ventricular Tachycardia

Remifentanil for Epicardial VT Ablation. Epicardial ablation of ventricular tachycardia (VT) presents multiple challenges for anesthetic management. General anesthesia lowers blood pressure, may interfere with arrhythmia mapping, and use of muscle relaxants precludes identification of the phrenic nerve. We describe a case in which remifentanil with minimal doses of midazolam was employed in a series of epicardial VT ablations and noninvasive programmed stimulations (NIPS), including 5 external cardioversions and discuss the advantages of this approach. (J Cardiovasc Electrophysiol, Vol. 22, pp. 464‐466)

Laryngeal mask airways in ear, nose, and throat procedures.

The use of laryngeal mask airway (LMA) and its variants in ear, nose, and throat procedures have been extensively described in case reports, retrospective reviews, and randomized clinical trials. The LMA has developed a considerable following because of its lack of tracheal stimulation, which can be a considerable advantage in ear, nose, and throat (ENT) procedures. The incidence of coughing on emergence has been shown to be lower with the LMA than with the endotracheal tube (ETT). Although other approaches to smooth emergence have been described, few would argue that it is as easy to achieve a smooth emergence with an ETT as with an LMA. Although patients certainly exist for whom the LMA is contraindicated, many will experience better results with the LMA because of the features delineated in this article.

Anesthetic Considerations for Transoral Robotic Surgery

During the past decade, robotic surgery has been progressively incorporated into the mainstream of cardio-thoracic and abdominopelvic surgery. With the recent US Food and Drug Administration approval of transoral robotic surgery (TORS) for the treatment of all benign tumors and select malignant tumors of the head and neck, robotic surgery has established its place in otolaryngologic surgery. Given the multispecialty applications and widespread use of robotic surgery, there exists a need for anesthesiologists to familiarize themselves with robotic surgery. This article focuses on TORS and the goal of which is to provide the anesthesiologist with a foundation for caring for the TORS patient in the perioperative period.

Safety and efficacy of drug-induced sleep endoscopy using a probability ramp propofol infusion system in patients with severe obstructive sleep apnea.

BACKGROUND:Drug-induced sleep endoscopy (DISE) uses sedative-hypnotics to induce moderate obstruction in sleep apnea patients, thereby facilitating anatomic assessment of obstructive physiology. Implementation of DISE with propofol requires a dosing strategy that reliably and efficiently produces obstruction while minimizing oxygen desaturation. METHODS:The surgeon in a prospective study of transoral robotic resection of the tongue base enrolled 97 patients with obstructive sleep apnea confirmed by polysomnography who failed continuous positive airway pressure. All patients were screened by DISE. Propofol dose was determined using custom software written in MATLAB, which has been previously described. Studies were performed in an operating room with standard monitors and resuscitation equipment. No topical anesthesia was used, and no IV drugs other than propofol were used. All patients received 2 L/min supplemental oxygen via a nasal cannula placed in the mouth. After initiation of propofol sedation, a pediatric bronchoscope was positioned via the naris to observe the velopharynx. The sedation sequence was continued until the clinical end point of obstruction onset was noted. Observation of the pharynx was performed for a sufficient period to obtain images of the anatomic site(s) of obstruction. The infusion was then terminated. Statistical analysis was performed with MATLAB (MathWorks, version 2012b). Comparison of saturation nadirs between DISE and subject sleep studies was performed with both the paired and unpaired Student t test. RESULTS:The subject population was characterized by a median body mass index of 32.1 (interquartile range [IQR] 6.8) kg/m2 and apnea-hypopnea index of 48 (IQR 32). All patients demonstrated obstruction within the design variables. Obstruction was observed after 236 (±57.9) seconds at an estimated effect-site concentration of 4.2 ± 1.3 mcg/mL. The median saturation nadir during DISE was significantly higher (91.4% (IQR 5.1)) than that during standard sleep studies (81.0% [IQR 11.2], P < 0.0001). Ninety-five percent confidence intervals for correlations between DISE saturation nadir and body mass index, age, apnea-hypopnea index, or administered propofol dose included zero in all cases. CONCLUSIONS:A propofol infusion strategy that requires limited experience with propofol dose selection and only 1 pump dosing change reliably produced airway obstruction in patients with severe sleep apnea. Clinical obstruction was achieved faster than target-controlled infusion-based systems for similar procedures reported in the literature. The observed degree of oxygen desaturation in the model system was within a clinically acceptable range.