Adducted vocal cords relieved by neuromuscular blocking drug: a cause of impaired mechanical ventilation when using a laryngeal mask airway: two photographically documented cases.

Two cases of vocal cord closure, which was responsible for acute intraoperative impairment of mechanical ventilation in two patients with entropy-controlled depth of anesthesia, are reported. Administration of low-dose neuromuscular blocking drug was associated with immediate vocal cord relaxation and restoration of efficient mechanical ventilation.

Hyperbaric oxygen therapy for vaso-occlusive crises in nine patients with sickle-cell disease.

INTRODUCTION: Vaso-occlusive crisis (VOC) is the most frequent complication of sickle-cell disease and is associated with significant acute bone pain. OBJECTIVE: To evaluate the feasibility and efficacy of hyperbaric oxygen therapy (HBOT) for severe VOC. METHODS: We report our retrospective experience with HBOT in VOC in nine patients and 15 HBOT sessions. RESULTS: All nine patients had received appropriate conventional treatment prior to HBOT. Pain scores using a Visual Analog Scale (0 to 10) determined whether HBOT was effective or not in improving symptoms. While no change in pain score occurred before the HBOT session, pain scores fell significantly from 3.3 prior to HBOT to 1.9 24 hours after HBOT (P = 0.002). While morphine dosage increased before HBOT (median morphine dose 23 mg per day and 35.95 mg per day respectively on Day -2 and Day -1, P = 0.04), the median morphine dose one day after HBOT (Day +1 23 mg per day) tended to be lower than Day -1 (P = 0.08), and decreased to zero 2 days after HBOT (P = 0.004). Two patients had ear pain during compression, requiring rapid interruption of the HBOT session, although neither patient had any sequelae. CONCLUSION: HBOT is feasible in sickle cell disease and appears to be effective in reducing the pain of VOC rapidly.

In flight auscultation: comparison of electronic and conventional stethoscopes.

OBJECTIVES: The ability to auscultate during air medical transport is compromised by high ambient noise levels. The aim of this study was to assess the capabilities of a traditional and an amplified stethoscope (which is expected to reduce background and ambient noise) to assess heart and breath sounds during medical transport in a Falcon 50 plane. METHODS: A prospective, double-blind, randomized study was performed. We tested 1 model of traditional stethoscope (Littman cardiology III) and 1 model of amplified stethoscope (Littman 3100). We studied heart and lung auscultation during real medical evacuations aboard Falcon 50 (medically configured). For each, the quality of auscultation was described using a numeric rating scale (ranging from 0 to 10, with 0 corresponding to "I hear nothing" and 10 corresponding to "I hear perfectly"). Comparisons were accomplished using a t test for paired values. RESULTS: A total of 32 comparative evaluations were performed. For cardiac auscultation, the value of the rating scale was 5.8 ± 1.5 and 6.4 ± 1.9, respectively, for the traditional and amplified stethoscope (P = .018). For lung sounds, quality of auscultation was estimated at 3.3 ± 2.4 for traditional stethoscope and at 3.7 ± 2.9 for amplified stethoscope (P = .15). CONCLUSIONS: Practicians in Falcon 50 are more able to hear cardiac sounds with an amplified than with a traditional stethoscope, whereas there is no significant difference concerning breath sounds auscultation.

Acute severe asthma: performance of ventilator at simulated altitude.

OBJECTIVE: Exacerbation of asthma can be seen during air transport. Severe patients, not responding to conventional therapy, require ventilator support. We evaluated the performance of two transport ventilators, built with turbine technology, the T-birdVSO2 and the LTV-1000, for use during aeromedical evacuation of acute severe asthma. We have assessed the ability of both the ventilators to deliver to an acute severe asthma model a tidal volume (Vt) set at different simulated altitudes, by changing the ambient air pressure. METHODS: The simulated cabin altitudes were 1500, 2500, and 3000 m (decompression chamber). Vt was set at 700 and 400 ml in an acute severe asthma lung model. Comparisons of the preset with the actual measured values were accomplished using a t-test. RESULTS: Comparisons between the actual delivered Vt and set Vt showed a significant difference starting at 1500 m for both the ventilators. The T-birdVSO2 showed a decrease in the volume delivered, with a negative variation of more than 10% compared with the Vt set. The LTV-1000 showed mostly an increase in the volume delivered. The delivered Vt remained within 10% of the set Vt. CONCLUSION: The accuracy of Vt delivery was superior with the LTV-1000 than with the T-birdVSO2, but the higher delivered Vt of the LTV-1000 are likely to be more harmful than lower delivered Vt of the T-birdVSO2.

Acute respiratory distress syndrome: performance of ventilator at simulated altitude.

BACKGROUND: Ventilation of Acute Respiratory Distress Syndrome (ARDS) is a challenge, and there is definitely a need for lack of variations between delivered and set tidal volume (Vt). We have assessed the ability of the ventilator T-birdVS02 and LTV-1000 to deliver to a lung model with ARDS a set Vt at different simulated altitudes. METHODS: We used a decompression chamber to mimic the hypobaric environment at a range of simulated cabin altitudes of 1,500, 2,500, and 3,000 m (4,000, 6,670, and 8,000 feet, respectively). Ventilators were tested with realistic parameters. Vt was set at 400 mL and 250 mL in an ARDS lung model. Comparisons of preset to actual measured values were accomplished using a t test for each altitude. RESULTS: The T-birdVS02 showed a decrease in the volume delivered. Comparisons of actual delivered Vt and set Vt demonstrated a significant difference starting at 1,500 m for a Vt set of 400 mL and at 2,500 m for Vt set of 250 mL. At these altitudes, the variations between Vt set and delivered were more than 10%. With decreasing barometric pressure, the LTV-1000 showed mostly an increase in volume delivered. Comparisons of actual delivered Vt and set Vt demonstrated a significant difference at 2,500 m for a Vt set of 400 mL and at 3,000 m for Vt set of 250 mL. The delivered Vt remained within 10% of the set Vt. CONCLUSION: Clinicians involved in aerial evacuations must keep in mind the performance and limitations of their ventilator system.

Cerebral monitoring of somatosensory evoked potentials during carotid surgery: a review of 100 cases.

The purpose of this study was to evaluate immediate and middle-term results of surgical carotid artery revascularization (CAR) with cerebral monitoring of intraoperative somatosensory evoked potentials (SEPs). Between 1998 and 2004, a total of 100 CARs in 86 patients were performed under general anesthesia with SEP monitoring. A shunt was inserted if SEP amplitude decreased by 50% or latency time increased by 10%. Immediate and middle-term results were analyzed retrospectively. The shunt insertion rate was 5%. Two transient ischemic attacks were observed, and one patient died postoperatively due to myocardial infarction. The cumulative stroke and death rate was 1% at 30 days. Intraoperative SEP monitoring with selective shunt placement can be used safely for carotid surgery. Randomized studies will be necessary to determine the respective indications for various cerebral monitoring techniques.