Emergency Surgical Airways Following Activation of a Difficult Airway Management Team in Hospitalized Critically Ill Patients: A Case Series.

INTRODUCTION: An emergency surgical airway (ESA) is widely recommended for securing the airway in critically ill patients who cannot be intubated or ventilated. Little is known of the frequency, clinical circumstances, management methods, and outcomes of hospitalized critically ill patients in whom ESA is performed outside the emergency department or operating room environments. METHODS: We retrospectively reviewed all adult patients undergoing ESA in our intensive care units (ICUs) and other hospital units from 2008 to 2012 following activation of our difficult airway management team (DAMT). RESULTS: Of 207 DAMT activations for native airway events, 22 (10.6%) events culminated in an ESA, with 59% of these events occurring in ICUs with the remainder outside the ICU in the context of rapid response team activations. Of patients undergoing ESA, 77% were male, 63% were obese, and 41% had a history of a difficult airway (DA). Failed planned or unplanned extubations preceded 61% of all ESA events in the ICUs, while bleeding from the upper or lower respiratory tract led to ESA in 44% of events occurring outside the ICU. Emergency surgical airway was the primary method of airway control in 3 (14%) patients, with the remainder of ESAs performed following failed attempts to intubate. Complications occurred in 68% of all ESAs and included bleeding (50%), multiple cannulation attempts (36%), and cardiopulmonary arrest (27%). Overall hospital mortality for patients undergoing ESA was 59%, with 38% of deaths occurring at the time of the airway event. CONCLUSION: An ESA is required in approximately 10% of DA events in critically ill patients and is associated with high morbidity and mortality. Efforts directed at early identification of patients with a difficult or challenging airway combined with a multidisciplinary team approach to management may reduce the overall frequency of ESA and associated complications.

Optimizing Anesthesia-Related Waste Disposal in the Operating Room: A Brief Report.

Misappropriation of noncontaminated waste into regulated medical waste (RMW) containers is a source of added expense to health care facilities. The operating room is a significant contributor to RMW waste production. This study sought to determine whether disposing of anesthesia-related waste in standard waste receptacles before patient entry into the operating room would produce a reduction in RMW. A median of 0.35 kg of waste was collected from 51 cases sampled, with a potential annual reduction of 13,800 kg of RMW to the host institution, and a cost savings of $2200.

Simulation in the operating room.

Simulation has become a significant training tool in the operating room (OR). It can be used in both simple task training and complex scenarios. The challenge for simulation in the OR is how to translate that which is learned, and perceived to beneficial, into behavioral change and improved patient outcomes. Simulation in the developing world is progressing, but is still hampered by a shortage of material, personnel funding.

Using arterial spin labeling perfusion MRI to explore how midazolam produces anterograde amnesia.

While our previous work suggests that the midazolam-induced memory impairment results from the inhibition of new association formation, little is known about the neural correlates underlying these effects beyond the effects of GABA agonists on the brain. We used arterial spin-labeling perfusion MRI to measure cerebral blood flow changes associated with the effects of midazolam on ability to learn arbitrary word-pairs. Using a double-blind, within-subject cross-over design, subjects studied word-pairs for a later cued-recall test while they were scanned. Lists of different word-pairs were studied both before and after an injection of either saline or midazolam. As expected, recall was severely impaired under midazolam. The contrast of MRI signal before and after midazolam administration revealed a decrease in CBF in the left dorsolateral prefrontal cortex (DLPFC), left cingulate gyrus and left posterior cingulate gyrus/precuneus. These effects were observed even after controlling for any effect of injection. A strong correlation between the midazolam-induced changes in neural activity and memory performance was found in the left DLPFC. These findings provide converging evidence that this region plays a critical role in the formation of new associations and that low functioning of this region is associated with anterograde amnesia.

Retrograde facilitation under midazolam: the role of general and specific interference.

In a double-blind, placebo-controlled experiment that used midazolam, a benzodiazepine that creates temporary amnesia, we compared acquisition and retention of paired associates of different types. Some word pairs were studied before the injection of saline or midazolam, and two lists of word pairs were studied after the injection. Critical comparisons involved retention of pairs that were practiced on all three lists, pairs studied on only one list, and pairs that involved recombining cue and response terms from one list to the next, as a function of drug condition. Previous research with benzodiazepines had found retrograde facilitation for material acquired prior to injection, compared with the control condition. One explanation for this facilitation is that the anterograde amnesia produced by the benzodiazepine frees up the hippocampus to better consolidate previously learned material (Wixted, 2004, 2005). We accounted for a rich data set using a simple computational model that incorporated interference effects (cue overload) at retrieval for both general (experimental context) interference and specific (stimulus term) interference without the need to postulate a role for consolidation. The computational model as an Excel spreadsheet may be downloaded from www.psychonomic.org/archive.

Assessing risk factors for postoperative nausea and vomiting: a retrospective study in patients undergoing retromastoid craniectomy with microvascular decompression of cranial nerves.

We have observed that patients, after retromastoid craniectomy (RMC) with microvascular decompression (MVD) of cranial nerves, frequently experienced postoperative nausea and vomiting (PONV). The authors conducted this study to track the incidence of PONV and to identify potential factors for PONV after RMC with MVD. Medical records from 185 adults, who underwent elective RMC with MVD, were identified and reviewed from January 2000 to December 2004. Extracted data included patient, anesthesia, and surgery related variables that were considered to have a possible effect on the patients experiencing PONV after RMC with MVD. Despite the use of intraoperative prophylactic ondansetron in 99% of patients, the overall incidence of PONV (nausea or emesis or both) was 60% during the first 24 hours postoperatively. It was higher for the patients after RMC with MVD of cranial nerve V [69%, 82/119, P=0.005, odds ratio (OR)=2.8]. Regression modeling demonstrated that female sex (OR=3.0, P=0.005) and use of desflurane (OR=2.8, P=0.003) were significant independent predictors of PONV. Prophylactic transdermal scopolamine patch administered preoperatively was associated with less PONV (OR=0.3, P=0.001). We concluded that PONV occurs frequently in adults recovering from RMC with MVD. The results of this study suggest that it may be necessary to administer a combination of antiemetics to decrease the incidence of PONV after RMC.

The incidence and outcome of perioperative pulmonary aspiration in a university hospital: a 4-year retrospective analysis.

We evaluated the current incidence and outcome of perioperative pulmonary aspiration (PPA) in the nonobstetric adult population at a tertiary university medical center. A 4-yr retrospective analysis (January 2001-December 2004) was conducted using both quality improvement data and the hospital-wide medical archive recording system. PPA was defined as either detection of nonrespiratory secretions from the tracheobronchial tree or development of new pulmonary symptoms and/or new abnormalities in chest radiographs within 24 hr postoperatively. Of 99,441 anesthetics, 14 cases had confirmed PPA. Seven of them (50%) occurred in connection with gastroesophageal procedures. All patients had one or more predisposing risk factors for PPA. PPA occurred under general anesthesia in 10 patients and under monitored anesthesia care in 4 patients. In general anesthesia cases, the aspiration was recognized immediately after induction in 5 patients and occurred during changing of the endotracheal tubes in 5. The PPA was detected during the surgical procedures in all the monitored anesthesia care cases. Six patients with confirmed PPA developed pulmonary complications, of which, one died. Ten of 14 (70%) cases of PPA were the result of improper anesthesia technique. The current incidence of PPA is 1 of 7103, with morbidity 1 of 16,573 and mortality 1 of 99,441.

Midazolam does not inhibit association formation, just its storage and strengthening.

RATIONALE: Although there have been many studies examining the effects of benzodiazepines on memory performance, their effects on working memory are equivocal and little is known about whether they affect the efficacy of practice of already learned material. OBJECTIVES: The objectives in two experiments were to examine (a) whether midazolam impairs performance on a working memory task designed to minimize mnemonic strategies such as rehearsal or chunking of information to be recalled and (b) the effect of midazolam on repeated practice of paired associates that were learned before drug administration. MATERIALS AND METHODS: Both experiments involved subcutaneous administration of 0.03 mg of saline or midazolam per kilogram of bodyweight in within-subject, placebo-controlled designs, involving 23 subjects in (a) and 31 in (b). RESULTS: The drug had no effect on the ability to recall the digits in serial order even though the encoding task prevented the digits from being rehearsed or maintained in an articulatory buffer. Paired associates that were learned before the injection showed a benefit of subsequent practice under saline but not under midazolam. CONCLUSIONS: The results suggest that (a) midazolam does not affect the formation of new associations in short-term memory provided that the presentation rate is not too fast to form these associations when sedated, despite the evidence that the drug blocks long-term memory (LTM) retention of associations; and (b) the potential for over-learning with practice of learned associations in LTM is adversely affected by midazolam such that repeated exposures do not strengthen new learning.

Drug-induced amnesia hurts recognition, but only for memories that can be unitized.

Midazolam is a drug that creates temporary anterograde amnesia. In a within-subjects, double-blind experiment, participants studied a list of stimuli after receiving an injection of midazolam in one session and after receiving saline in another session. The lists consisted of three types of stimuli: words, photographs, and abstract pictures. Recognition memory was tested at the end of each session. Memory was reliably poorer in the midazolam condition than the saline condition, but this amnesic effect was significantly smaller for pictorial stimuli than for words and almost nonexistent for abstract pictures. We argue that the less familiar the stimulus, the less likely it is to be associated with an experimental context. These data bolster our claim that unitization increases the chances of episodic binding and that drug-induced amnesia prevents episodic binding regardless of unitization.

The anesthetic management of a patient with Cohen syndrome.

Cohen syndrome is a rare genetic disorder caused by autosomal recessive inheritance and is characterized by the following features: mental retardation, infantile hypotonia, micrognathia, narrow and high-arched palate, microcephaly, prominent upper central incisors, poor dentition, short stature, and truncal obesity. Some patients have strabismus, myopia, optic atrophy, and total blindness. A small number of cases present with heart defects or mitral valve prolapse. Only approximately 100 cases have been reported in the world literature. The administration of general anesthesia in patients with Cohen syndrome can be a challenge because most of these patients are mentally retarded and uncooperative and have facial malformations that may make intubation difficult. We present our experience with the anesthetic management of a patient with Cohen syndrome.

Pituitary apoplexy presenting as unilateral third cranial nerve palsy after coronary artery bypass surgery.

UNLABELLED: The new onset of pituitary apoplexy is a rare perioperative complication of coronary artery bypass surgery. A variety of clinical presentations of pituitary apoplexy have been reported including absence of clinical symptoms or headache, sudden deterioration of mental status, visual changes, Addisonian crisis, and ophthalmoplegia, including third cranial nerve palsy and/or ptosis. Early diagnosis and treatment usually results in excellent outcome. We report a case of pituitary apoplexy that presented with only a unilateral dilated pupil, ptosis, and vision change within 3 h after coronary artery bypass surgery. The patient recovered fully after early pituitary tumor resection and hormonal therapy. IMPLICATIONS: Unilateral pupil dilation is a rare perioperative complication after coronary artery bypass surgery. We report a case of pituitary apoplexy that presented clinically as unilateral dilated pupil, ptosis, and visual loss shortly after coronary artery bypass surgery.

Mice with glycine receptor subunit mutations are both sensitive and resistant to volatile anesthetics.

UNLABELLED: We used two mouse lines with glycine receptor mutations to determine whether glycine receptors might play an important role in anesthetic responses in vivo. Spastic (spA) mutants were slightly more sensitive (P = 0.02) to enflurane in the loss-of-righting reflex assay (50% effective concentration [EC(50)] = 1.17 +/- 0.06 atm for controls versus 0.97 +/- 0.06 atm for spA) but were also substantially more resistant (P = 0.01) to enflurane in the tail clamp assay (EC(50) = 1.96 +/- 0.10 atm for controls versus 2.58 +/- 0.25 atm for spA). spA mice were also more sensitive to halothane (P < 0.001) in the loss-of-righting reflex assay (EC(50) = 0.81 +/- 0.03 atm for controls versus 0.57 +/- 0.04 atm for spA), but the responses of mutant and control mice to tail clamp in the presence of halothane were similar. Spasmodic control and mutant mice did not differ in their responses to the two drugs. Sleep time was substantially longer in both mutant mouse lines after injection of three hypnotics (midazolam, pentobarbital, and ethanol). Our results suggest a complex involvement of glycinergic pathways in mediating anesthetic responses. Greater sensitivity to the hypnotic effect of enflurane, halothane, midazolam, pentobarbital, and ethanol in mutant mice with diminished glycinergic capacity suggests that glycinergic activity is inversely related to hypnosis, whereas resistance to enflurane in the tail clamp assay suggests that glycinergic activity potentiates the minimum alveolar anesthetic concentration response. Halothane seems to share some, but not all, of enflurane's mechanisms, indicating that not all volatile anesthetics modulate glycinergic pathways equally. IMPLICATIONS: We tested two mouse lines with glycine receptor mutations to determine whether glycine receptors might play an important role in anesthetic responses in vivo. Both sensitivity and resistance to common anesthetics were observed in mutant mice, depending on the behavioral end-point evaluated.