Warning criteria for MEP monitoring during carotid endarterectomy: a retrospective study of 571 patients.

Monitoring of transcranial electrical motor evoked potentials (tcMEP) during carotid endarterectomy (CEA) has been shown to effectively detect intraoperative cerebral ischemia. The unique purpose of this study was to evaluate changes of MEP amplitude (AMP), area under the curve (AUC) and signal morphology (MOR) as additional MEP warning criteria for clamping-associated ischemia during CEA. Therefore, the primary outcome was the number of MEP alerts (AMP, AUC and MOR) in the patients without postoperative motor deficit (false positives). We retrospectively reviewed data from 571 patients who received CEA under general anesthesia. Monitoring of somatosensory evoked potentials (SSEP) and tcMEP was performed in all cases (all-or-none MEP warning criteria). The percentages of false positives (primary parameter) of AMP, AUC and MOR were evaluated according to the postoperative motor outcome. In the cohort of 562 patients, we found significant SSEP/MEP changes in 56 patients (9.96%). In 44 cases (7.83%) a shunt was inserted. Nine patients (1.57%) were excluded due to MEP recording failure. False positives were registered for AMP, AUC and MOR changes in 121 (24.01%), 148 (29.36%) and 165 (32.74%) patients, respectively. In combination of AMP/AUC and AMP/AUC/MOR false positives were found in 9.52% and 9.33% of the patients. This study is the first to evaluate the correctness of the MEP warning criteria AMP, AUC and MOR with regard to false positive monitoring results in the context of CEA. All additional MEP warning criteria investigated produced an unacceptably high number of false positives and therefore may not be useful in carotid surgery for adequate detection of clamping-associated ischemia.

A 'metabolic bundle' including Oxandrolone in optimising the metabolic status of severely burn injured patients: a retrospective analysis of the first 50 patients.

Objective: Severe burn injuries are associated with a rapid escalating hypermetabolic state and catabolism of muscle mass. To ameliorate this process a standardized approach using pharmacological and non-pharmacological interventions was implemented within a single burns center. Whilst individual components of this standardized package are well documented in the literature, their collective or bundled effect has not as yet been assessed. The aim of this study was to evaluate the efficacy of this standardized bundle of metabolic modulators and assess the safety of including the anabolic steroid oxandrolone within it. Methods: This retrospective observational study constituted all patients in whom the metabolic bundle including oxandrolone therapy was applied. The other elements of the metabolic bundle consisted of early surgical burn excision within seven days to completion, early active mobilization, increased ambient room temperature, expediated carbohydrate and protein rich enteral feeding with glutamine and trace element supplements (such as copper and zinc). Finally, administration of propranolol as a non-selective beta-blocker. Data collection was through review of the patient data management system focusing on the outcome criteria and hepatic blood values. Results: The study looked at fifty consecutive patients meeting the inclusion criteria. Median patient age and burned total body surface area (TBSA) were 62 years [51.75; 73] and 33.75% [24.75; 51] respectively with an abbreviated burn severity index (ABSI) of 10 [9; 10.25]. Definitive surgical burn wound excision was completed in 44 patients [88%] within 7 days. 39 patients (78%) received propranolol over a therapeutic period of 29 days [19; 44]. Glutamine was supplemented in 45 patients (90%), while zinc and copper were applied to 42 (84%) and 31 (62%) respectively. Significant low zinc values were noted at therapeutic onset (6.5 mmol/l [4.7; 7.9]) requiring sustained substitution over 37.5 days [22; 46.75]). In respect of the inclusion criteria, all patients received oxandrolone at 20 mg/day [20; 20]. This was commenced on day 6.5 [4; 14] post burn injury and continued over 26 days [19; 31]. Despite a transitory elevation of hepatic enzyme values (ALT, GGT), these were only clinically relevant (>10 µmol/l*S) in 2.4% and 4.6% of all measurements respectively. None were sufficiently of concern to merit cessation of treatment. Conclusion: The application of a standardised bundle of metabolic treatment options of severe burns injured patients is reliable, repeatable and safe. Potential concerns of oxandrolone treatment regarding hepatic compromise remain unfounded.

Reducing the Indication for Ventilatory Support in the Severely Burned Patient: Results of a New Protocol Approach at a Regional Burn Center.

Initial management of the severely injured routinely includes sedation and mechanical ventilatory support. However, nonjudiciously applied mechanical ventilatory support can itself lead to poorer patient outcomes. In an attempt to reduce this iatrogenic risk, a standardized, in-house, five-point protocol providing clinical guidance on the use and duration of ventilation was introduced and analyzed, and the impact on patient outcomes was assessed. In 2007, a protocol for early spontaneous breathing was introduced and established in clinical practice. This protocol included: 1) early extubation (≤6 hours after admission) in the absence of absolute ventilatory indication; 2) avoidance of "routine intubation" in spontaneously breathing patients; 3) early postoperative extubation, including patients requiring multiple surgical interventions; 4) intensive chest and respiratory physiotherapy with routine application of expectorants; and 5) early active mobilization. A retrospective clinical study compared patients (group A) over a 2-year period admitted under the new protocol with a historical patient group (group B). Patients in group A (n = 38) had fewer ventilator days over the time-course of treatment (3 [1; 5.8] vs 18.5 days [0.5; 20.5]; P = .0001) with a lower rate of tracheostomies (15.8 vs 54%; P = .0003). Patients on ventilation at admission in group A had shorter ventilation periods after admission (4.75 [4; 22.25] vs 378 hours [8.5; 681.5]; P = .0003), and 66.7% of these patients were extubated within 6 hours of admission (vs 9.1% in group B). No patients fulfilling the inclusion criteria required re- or emergency intubation. In the first 5 days of treatment, significantly lower Sequential Organ Failure Assessment scores were recorded in group A. There was also a trend for lower mortality rates (0 [0%] vs 6 [14%]), sepsis rates (24 [63.2%] vs 37 [88.1%]), and cumulative fluid balance on days 3 and 7 in group A. In contrast, group A demonstrated an elevated rate of pneumonia (15 [39.5%] vs 8 [19%]). These trends, however, lacked statistical significance. Our five-point protocol was safe and easily translated into clinical practice. In the authors experience, this protocol significantly reduced the ventilatory period in severely injured. Furthermore, this study suggests that many injured may be over-treated with routine ventilation, which carries accompanying risks.

Comparison of Enk Fibreoptic Atomizer with translaryngeal injection for topical anaesthesia for awake fibreoptic intubation in patients at risk of secondary cervical injury: A randomised controlled trial.

BACKGROUND: Two methods of topical anaesthesia for awake fibreoptic intubation (FOI) in patients at risk of secondary cervical injury were compared: the translaryngeal injection (TLI) technique and the Enk Fibreoptic Atomizer. OBJECTIVE: The objective of this study was to determine which system of topical anaesthesia provides the fastest and most comfortable awake FOI, using the oral approach. DESIGN: A randomised controlled study. SETTING: A single centre trial between 2009 and 2011. PATIENTS: One hundred and twenty patients (63 women, 57 men) who underwent neurosurgery of the spine at Klinikum St. Georg Leipzig were randomly allocated into two groups (group TLI, 61 patients; group ENK-ATOMIZER, 59 patients). Inclusion criteria were an American Society of Anesthesiology (ASA) physical status of 1 to 3, age 18 to 80 years, and those who met any one of three indications for FOI - cervical instability, predicted difficult airway, a BMI greater than 40 kg m(-2), and who gave written informed consent.Exclusion criteria were emergency awake FOI, mental disability/delirium, polytrauma and contraindication to TLI. INTERVENTIONS: Two anaesthesiologists experienced in both techniques performed all anaesthesia procedures within the study. MAIN OUTCOME MEASURES: The primary outcome was the timing sequence of awake FOI. The incidence of coughing/gagging, ease of tracheal tube placement, mucosal bleeding, cardiopulmonary stability and postoperative outcomes were also investigated. RESULTS: Awake FOI was significantly faster using the TLI technique (mean, 191 s; range, 123 to 447 s; SD, 83.5) than the Enk Fibreoptic Atomizer [mean, 430 s; range, 275 to 773 s; SD, 124.9; (P = 0.0001)]. Patients in group TLI exhibited significantly less gagging (P = 0.047) but more mucosal bleeding (P <  .001). CONCLUSION: Awake FOI using the TLI technique was faster and provided better topical anaesthesia with less gagging during endoscopic intubation. However, the TLI technique was also more invasive. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT00948350.

Intraoperative multimodal evoked potential monitoring during carotid endarterectomy: a retrospective study of 264 patients.

BACKGROUND: Methods for detecting intraoperative cerebral ischemia arising from internal carotid artery (ICA) cross-clamping during carotid endarterectomy (CEA) should be sensitive, specific, and rapid to prevent intraoperative stroke. We had 3 objectives pertaining to this: (1) investigation of the rates of success of multimodal evoked potential (mEP) monitoring using a combination of median nerve (m) somatosensory (SS) EPs, tibial nerve SSEPs (tSSEPs), and transcranial electrical stimulated motor EPs (tcMEPs); (2) evaluation of the rates of false-negative mEP results; and (3) analysis of the relationship between different time periods associated with ICA cross-clamping and the postoperative outcome of motor function in patients with significant changes in mEP monitoring. METHODS: Two hundred sixty-four patients undergoing CEA using general anesthesia with monitoring of bilateral mSSEPs, tSSEPs, and tcMEPs were retrospectively reviewed between 2009 and 2012. The rates of successful assessment of mEPs were investigated, and the rate of false-negative mEP results was analyzed. Different time periods (T1--time of clamping, T2--clamping to significant mEP changes, T3--significant mEP change to intervention, and T4--intervention to recovery of EP) were tested using Welch t test for significant association with postoperative motor deficit. RESULTS: (1) Multimodal EP monitoring was achieved in 241 patients (91.3%, point estimate [PE] 0.91, confidence interval [CI] 0.87 to 0.94), whereas none of the modalities were recordable in one case (PE 0.0038, CI 0.0002 to 0.019). Additionally, tSSEP was not recordable in 21 patients (PE 0.08, CI 0.05 to 0.12), and we found one case of isolated failure of tcMEP recording (PE 0.0038, CI 0.0002 to 0.019). (2) False-negative mEP results were found in 1 patient (0.4%; PE 0.0038, CI 0.0002 to 0.019). Significant mEP changes occurred in 32 patients (12.1%), and thus, arterioarterial shunt was performed in 17 (6.4%) patients. Eleven patients (4.2%) showed transient and 1 showed permanent postoperative motor deficit. (3) There was no significant difference regarding any of the time periods associated with ICA cross-clamping and postoperative alteration of motor function (T1: P = 0.19, CI -30.1 to 6.8 minutes; T2: P = 0.38, CI -23 to 9.5 minutes; T3: P = 0.25, -9.7 to 2.8 minutes; T4: P = 0.42, CI to -15.5 to 7.0 minutes). CONCLUSIONS: Multimodal EP monitoring is applicable during CEA. The 0.4% false-negative rate suggests an advantage of mEP monitoring when compared with isolated mSSEP monitoring. Our data suggest that periods of time during cross-clamping were not significantly associated with postoperative motor deficit. However, the small number of patients limits the conclusiveness of these findings. mEP monitoring could not prevent a postoperative motor deficit in all patients, but our results suggest that it is a useful adjunct to mSSEP monitoring.

Comparison of Aintree and Fastrach techniques for low-skill fibreoptic intubation in patients at risk of secondary cervical injury: a randomised controlled trial.

BACKGROUND: We compared two methods of asleep fibreoptic intubation in patients at risk of secondary cervical injury: the Aintree Intubation Catheter via a classic laryngeal mask airway (cLMA) versus the Fastrach technique via the intubating laryngeal mask airway (iLMA). OBJECTIVE: To test which system has the highest rate of successful intubations in the clinical setting. DESIGN: A randomised controlled study. SETTING: Single-centre, between 2007 and 2010. PATIENTS: We randomly allocated 80 patients (30 women and 50 men) who underwent elective neurosurgery of the cervical spine to either group, placed in a neutral position and wearing a soft cervical collar. Entry criteria were ASA status 1 to 3, age 18 to 80 years and written informed consent. Exclusion criteria were patients with cervical instability, known or predicted difficult airway, BMI greater than 40  kg  m⁻² and symptomatic gastro-oesophageal reflux. INTERVENTIONS: Two anaesthetists who were experienced in both techniques performed all anaesthesia procedures within the study. There was a maximum of three attempts for performing each technique. MAIN OUTCOME MEASURES: The primary outcome was the rate of successful fibreoptic intubation in a neutral position. We also investigated the timing sequence for both techniques, the Brimacombe and Berry Bronchoscopy Score, and differences in technical aspects. RESULTS: All 40 patients in the Aintree group but only 31 patients in the Fastrach group were intubated successfully. Thus, fibreoptic intubation failed significantly less using the Aintree technique (P = 0.002). For secondary outcomes, the cLMA was faster (260 versus 289  s, P = 0.039) and easier (P = 0.036) to insert than the iLMA. The fibreoptic view of the glottis according to the Brimacombe and Berry Bronchoscopy Score was better (P = 0.016) and the tracheal tube was easier to insert (P = 0.010) in the Aintree group. CONCLUSION: Fibreoptic intubation using the Aintree system was more successful than the Fastrach technique in our population of patients in a neutral position wearing a soft cervical collar. The differences in the time to successful intubation between the two groups are unlikely to be clinically relevant.