Simulation-based Assessment to Reliably Identify Key Resident Performance Attributes.

BACKGROUND: Obtaining reliable and valid information on resident performance is critical to patient safety and training program improvement. The goals were to characterize important anesthesia resident performance gaps that are not typically evaluated, and to further validate scores from a multiscenario simulation-based assessment. METHODS: Seven high-fidelity scenarios reflecting core anesthesiology skills were administered to 51 first-year residents (CA-1s) and 16 third-year residents (CA-3s) from three residency programs. Twenty trained attending anesthesiologists rated resident performances using a seven-point behaviorally anchored rating scale for five domains: (1) formulate a clear plan, (2) modify the plan under changing conditions, (3) communicate effectively, (4) identify performance improvement opportunities, and (5) recognize limits. A second rater assessed 10% of encounters. Scores and variances for each domain, each scenario, and the total were compared. Low domain ratings (1, 2) were examined in detail. RESULTS: Interrater agreement was 0.76; reliability of the seven-scenario assessment was r = 0.70. CA-3s had a significantly higher average total score (4.9 ± 1.1 vs. 4.6 ± 1.1, P = 0.01, effect size = 0.33). CA-3s significantly outscored CA-1s for five of seven scenarios and domains 1, 2, and 3. CA-1s had a significantly higher proportion of worrisome ratings than CA-3s (chi-square = 24.1, P < 0.01, effect size = 1.50). Ninety-eight percent of residents rated the simulations more educational than an average day in the operating room. CONCLUSIONS: Sensitivity of the assessment to CA-1 versus CA-3 performance differences for most scenarios and domains supports validity. No differences, by experience level, were detected for two domains associated with reflective practice. Smaller score variances for CA-3s likely reflect a training effect; however, worrisome performance scores for both CA-1s and CA-3s suggest room for improvement.

Validation of Respiratory Inductance Plethysmography for Measuring Tidal Volume in Swine.

Measuring tidal volume (VT) in nonintubated swine or swine with leaking breathing circuits is challenging. The aim of this study was to validate respiratory inductance plethysmography (RIP) for measuring VT in swine that are comparable in size to adult humans. To determine calibration curves, VT and RIP readings were obtained from anesthetized swine (n = 8; weight, 46-50 kg) during positive-pressure (mechanical) ventilation and spontaneous breathing. For positive-pressure ventilation, 6 pigs were mechanically ventilated by using the pressure-control mode. The 2 pigs in the spontaneously breathing cohort each received a single intravenous bolus dose of propofol to abolish spontaneous breathing; VT was measured during gradual return of their respiratory drive. A flow-volume sensor was placed between the proximal end of the endotracheal tube and breathing circuit for the recording of inspiratory and expiratory VT. RIP readings were recorded by using 2 bands, which simultaneously measured ribcage and abdominal excursions. The data revealed that VT was linearly correlated with the movements of both ribcage and abdomen as measured by using plethysmography over a large range of tidal volume (44 to 1065 mL). In addition, the intercept of the linear equation was small or even negative during spontaneous breathing but increased significantly (maximum, 145 mL, 59.2 ± 35.1 mL) during positive pressure ventilation. Our results indicate that VT in swine can be calculated by using a simple univariate linear regression equation with RIP readings obtained during either mechanical ventilation or spontaneous breathing.

Continuous positive airway pressure and ventilation are more effective with a nasal mask than a full face mask in unconscious subjects: a randomized controlled trial.

INTRODUCTION: Upper airway obstruction (UAO) is a major problem in unconscious subjects, making full face mask ventilation difficult. The mechanism of UAO in unconscious subjects shares many similarities with that of obstructive sleep apnea (OSA), especially the hypotonic upper airway seen during rapid eye movement sleep. Continuous positive airway pressure (CPAP) via nasal mask is more effective at maintaining airway patency than a full face mask in patients with OSA. We hypothesized that CPAP via nasal mask and ventilation (nCPAP) would be more effective than full face mask CPAP and ventilation (FmCPAP) for unconscious subjects, and we tested our hypothesis during induction of general anesthesia for elective surgery. METHODS: In total, 73 adult subjects requiring general anesthesia were randomly assigned to one of four groups: nCPAP P0, nCPAP P5, FmCPAP P0, and FmCPAP P5, where P0 and P5 represent positive end-expiratory pressure (PEEP) 0 and 5 cm H2O applied prior to induction. After apnea, ventilation was initiated with pressure control ventilation at a peak inspiratory pressure over PEEP (PIP/PEEP) of 20/0, then 20/5, and finally 20/10 cm H2O, each applied for 1 min. At each pressure setting, expired tidal volume (Vte) was calculated by using a plethysmograph device. RESULTS: The rate of effective tidal volume (Vte > estimated anatomical dead space) was higher (87.9% vs. 21.9%; P<0.01) and the median Vte was larger (6.9 vs. 0 mL/kg; P<0.01) with nCPAP than with FmCPAP. Application of CPAP prior to induction of general anesthesia did not affect Vte in either approach (nCPAP pre- vs. post-; 7.9 vs. 5.8 mL/kg, P = 0.07) (FmCPAP pre- vs. post-; 0 vs. 0 mL/kg, P = 0.11). CONCLUSIONS: nCPAP produced more effective tidal volume than FmCPAP in unconscious subjects. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01524614.

Effectiveness of breathing through nasal and oral routes in unconscious apneic adult human subjects: a prospective randomized crossover trial.

BACKGROUND: The authors hypothesized that mouth ventilation by a resuscitator via the nasal route ensures a more patent airway and more effective ventilation than does ventilation via the oral route and therefore would be the optimal manner to ventilate adult patients in emergencies, such as during cardiopulmonary resuscitation. They tested the hypothesis by comparing the effectiveness of mouth-to-nose breathing (MNB) and mouth-to-mouth breathing (MMB) in anesthetized, apneic, adult subjects without muscle paralysis. METHODS: Twenty subjects under general anesthesia randomly received MMB and MNB with their heads placed first in a neutral position and then an extended position. A single operator performed MNB and MMB at the target breathing rate of 10 breaths/min, inspiratory:expiratory ratio 1:2 and peak inspiratory airway pressure 24 cm H2O. A plethysmograph was used to measure the amplitude change during MMB and MNB. The inspiratory and expiratory tidal volumes during MMB and MNB were calculated retrospectively using the calibration curve. RESULTS: All data are presented as medians (interquartile ranges). The rates of effective ventilation (expired volume > estimated anatomic dead space) during MNB and MMB were 91.1% (42.4-100%) and 43.1% (42.5-100%) (P < 0.001), and expired tidal volume with MMB 130.5 ml (44.0-372.8 ml) was significantly lower than with MNB 324.5 ml (140.8-509.0 ml), regardless of the head position (P < 0.001). CONCLUSIONS: Direct mouth ventilation delivered exclusively via the nose is significantly more effective than that delivered via the mouth in anesthetized, apneic adult subjects without muscle paralysis. Additional studies are needed to establish whether using this breathing technique during emergency situations will improve patient outcomes.

Effect of effort pain after upper abdominal surgery on two independent measures of respiratory function.

STUDY OBJECTIVE: To determine how effort pain interacts with changing pulmonary function after upper abdominal incisions. DESIGN: Prospective, case-controlled study. SETTING: Academic teaching hospital. PATIENTS: 34 ASA physical status I, II, and III patients recovering from elective, major incisional, upper abdominal surgery. MEASUREMENTS: Manometry (maximal inspiratory and expiratory pressure) and spirometry (forced vital capacity, forced expiratory volume during the first second, peak expiratory flow) for three postoperative days. Pain scores (Visual Analog Pain Scale; VAS) at rest and after the manometric or spirometric efforts. MAIN RESULTS: Effort pain during either manometry or spirometry was greater than pain at rest on the first postoperative day. Maximal respiratory pressure concomitantly recovered with pain during daily efforts (slopes: -0.429 and -0.278% max/mm VAS; P < 0.05). Spirometric measurements showed minimal improvement. CONCLUSION: The direct relationship between resolution of pain with effort and direct measures of respiratory muscle effort using manometry, but not those obtained less directly by spirometry, suggests that assessing interactions between pain and effort requires a direct, quantifiable measure of effort.

Nasal ventilation is more effective than combined oral-nasal ventilation during induction of general anesthesia in adult subjects.

BACKGROUND: The authors hypothesized that nasal mask ventilation may be more effective than combined oral-nasal mask ventilation during induction of general anesthesia. They tested this hypothesis by comparing the volume of carbon dioxide removed per breath with nasal versus combined oral-nasal mask ventilation in nonparalyzed, apneic, adult subjects during induction of general anesthesia. METHODS: Fifteen adult subjects receiving general anesthesia were ventilated first with a combined oral-nasal mask and then with only a nasal mask. The patient's head was maintained in a neutral position, without head extension or lower jaw thrust. Respiratory parameters were recorded simultaneously from both the nasal and oral masks regardless of ventilation approach. RESULTS: The volume of carbon dioxide removed per breath during nasal mask ventilation (median, 5.0 ml; interquartile range, 3.4-8.8 ml) was significantly larger than that during combined oral-nasal mask ventilation (median, 0.0 ml; interquartile range, 0.0-0.4 ml; P = 0.001); even the peak inspiratory airway pressure during nasal ventilation (16.7 +/- 2.7 cm H2O) was lower than that during combined oral-nasal ventilation (24.5 +/- 4.7 cm H2O; P = 0.002). The expiratory tidal volume during nasal ventilation (259.8 +/- 134.2 ml) was also larger than that during combined oral-nasal ventilation (98.9 +/- 103.4 ml; P = 0.003). CONCLUSIONS: Nasal mask ventilation was more effective than combined oral-nasal mask ventilation in apneic, nonparalyzed, adult subjects during induction of general anesthesia. The authors suggest that nasal mask ventilation, rather than full facemask ventilation, be considered during induction of anesthesia.

Pneumothorax during argon beam-enhanced coagulation in laparoscopy.

Argon beam coagulation is an effective modality to control rapid diffuse hemorrhage. We present a case of pneumothorax from argon beam coagulation used during laparoscopic surgery. We discuss potential cardiopulmonary consequences of this relatively new application of argon beam technology.