Impact of direct laryngoscopy vs. videolaryngoscopy on signal quality of recurrent laryngeal nerve monitoring in thyroid surgery: a randomised parallel group trial.

In thyroid surgery, intra-operative neuromonitoring signals of the recurrent laryngeal nerve can be detected by surface electrodes on a tracheal tube positioned at the vocal fold level. The incidence of difficult tracheal intubation in patients undergoing thyroidectomy for nodular goitre ranges from 5.3% to 20.5%. The aim of this study was to compare videolaryngoscopy with conventional direct laryngoscopy as methods for proper placement of the surface electrode to prevent insufficient intra-operative nerve signal quality. In this prospective randomised trial, adult patients requiring tracheal intubation during thyroid surgery were randomly allocated to two groups of C-MAC® (Macintosh style blade) videolaryngoscope or direct laryngoscopy using the Macintosh laryngoscope. Primary outcome was the incidence of insufficient signal electromyogram amplitude level (< 500 µV) after successful tracheal intubation. A total of 260 (130 per group) participants were analysed. An insufficient signal was more frequent with direct laryngoscopy (35/130, 27%), compared with C-MAC (12/130, 9%, p < 0.001). First-pass tracheal intubation success rate was lower with direct laryngoscopy (86/130 (66%)) compared with the C-MAC (125/130 (96%)) (p < 0.0001). Cormack and Lehane grade ≥ 3 was observed more frequently with direct laryngoscopy (16/130 (12%)), compared with the C-MAC (0/130, (0%)) (p < 0.0001). The results suggest that videolaryngoscopy has an impact on the quality of the initial intra-operative neuromonitoring signal in patients undergoing thyroid surgery, and this technique can provide optimised surface electrode positioning.

Recurrent laryngeal nerve monitoring during totally robot-assisted Ivor Lewis esophagectomy.

PURPOSE: The robot-assisted approach for Ivor Lewis esophagectomy offers an enlarged, three-dimensional overview of the intraoperative situs. The vagal nerve (VN) can easily be detected, preserved, and intentionally resected below the separation point of the recurrent laryngeal nerve (RLN). However, postoperative vocal cord paresis can result from vagal or RLN injury during radical lymph node dissection, presenting a challenge to the operating surgeon. METHODS: From May to August 2019, 10 cases of robot-assisted minimally invasive esophagectomy (RAMIE) with extended 2-field lymphadenectomy, performed at the University Medical Center Mainz, were included in a prospective cohort study. Bilateral intermittent intraoperative nerve monitoring (IONM) of the RLN and VN was performed, including pre- and postoperative laryngoscopy assessment. RESULTS: Reliable mean signals of the right VN (2.57 mV/4.50 ms) and the RLN (left 1.24 mV/3.71 ms, right 0.85 mV/3.56 ms) were obtained. IONM facilitated the identification of the exact height of separation of the right RLN from the VN. There were no cases of permanent postoperative vocal paresis. Median lymph node count from the paratracheal stations was 5 lymph nodes. CONCLUSION: IONM was feasible during RAMIE. The intraoperative identification of the RLN location contributed to the accuracy of lymph node dissection of the paratracheal lymph node stations. RLN damage and subsequent postoperative vocal cord paresis can potentially be prevented by IONM.

Assessment of haemoglobin measurement by several methods - blood gas analyser, capillary and venous HemoCue® , non-invasive spectrophotometry and laboratory assay - in term and preterm infants.

A laboratory haematology analyser is the gold standard for measuring haemoglobin concentration but has disadvantages, especially in neonates. This study compared alternative blood-sparing and non-invasive methods of haemoglobin concentration measurement with the gold standard. Haemoglobin concentrations were measured using a laboratory haematology analyser (reference method), blood gas analyser, HemoCue® using venous and capillary blood samples and a newly developed non-invasive sensor for neonates < 3 kg. A total of 63 measurements were performed. Body weight (2190 (1820-2520 [967-4450]) g) and haemoglobin concentration (12.3 (10.6-15.2 [8.2-20.5]) g.dl-1 ) varied widely. Bias/limits of agreement between the alternative methods and reference method were -0.1/-1.2 to 1.0 g.dl-1 (blood gas analyser), -0.4/-1.8 to 1.1 g.dl-1 (HemoCue, venous blood), 0.7/-1.9 to 3.2 g.dl-1 (HemoCue, capillary blood) and -1.2/-4.3 to 2 g.dl-1 (non-invasive haemoglobin measurement). Perfusion index, body weight and fetal haemoglobin concentration did not affect the accuracy of the alternative measurement methods, and these were successfully applied in term and preterm infants. However, the accuracies of non-invasive haemoglobin measurement and HemoCue of capillary blood especially lacked sufficient agreement with that of the reference method to recommend these methods for clinical decision making.

[Autonomic dysfunction and cardiac arrhythmia in patients with obstructive and central sleep apnea]. / Autonome Dysregulation und kardiale Arrhythmien bei Patienten mit obstruktiver und zentraler Schlafapnoe.

Obstructive sleep apnea and central sleep apnea with Cheyne-Stokes respiration are associated with an increased risk of cardiac arrhythmia. Apnea- associated arrhythmia may contribute to sudden cardiac death and premature mortality in those patients. Both forms of sleep apnea excert strong modulatory effects on the autonomic system with a special autonomic profile. Profound vagal activity is leading to bradyarrhythmias, and sypathico-excitation to tachyarrhythmias. Atrial fibrillation and ventricular arrhythmias in obstructive and central sleep apnea patients are mainly found in combination with cardiovascular comorbidity (coronary heart disease, hypertensive heart disease, chronic heart failure). Bradyarrhythmias in OSA are induced by a cardioinhibitory vagal reflex due to obstructed airway. CPAP-therapy has been demonstrated to reduce arrhythmias.

A comparison of desflurane versus propofol: the effects on early postoperative lung function in overweight patients.

BACKGROUND: In this study, we evaluated the influence of propofol versus desflurane anesthesia in overweight patients on postoperative lung function and pulse oximetry values. METHODS: We prospectively studied 134 patients with body mass indices of 25 to 35 kg/m(2) undergoing minor peripheral surgery lasting 40 to 120 minutes. Patients were randomly assigned to receive propofol (total IV anesthesia) or desflurane anesthesia via a tracheal tube targeting bispectral index values of 40 to 60. Premedication, adjuvant drug usage, and ventilation were standardized. We measured oxyhemoglobin saturation and lung function preoperatively (baseline), and at 10 minutes, 0.5 hour, 2 hours, and 24 hours after tracheal extubation. All values were measured with the patient supine, in a 30° head-up position. Changes from preoperative baseline values were first analyzed for the impact of body mass index and type of anesthesia using univariate methods, followed by linear regression and multivariate analysis of variance. RESULTS: Within the first 2 hours after surgery, the propofol group displayed lower oxyhemoglobin saturation (at 2 hours, mean ± SD, 93.8% ± 2.0% vs 94.6% ± 2.1%; P < 0.007) and lung function (forced vital capacity, forced expiratory volume exhaled in 1 second [FEV(1)], peak expiratory flow, midexpiratory flow [MEF], forced inspiratory vital capacity, and peak inspiratory flow; between 11% and 20% larger reduction from baseline in the propofol group, all P < 0.001) compared with the desflurane group. Even 24 hours after surgery, FEV(1), peak expiratory flow, MEF, forced inspiratory vital capacity, and peak inspiratory flow were reduced more in the propofol group (all P < 0.01). At 2 hours after extubation, increasing obesity was associated with decreasing FEV(1) and MEF in patients anesthetized with propofol but not desflurane (P < 0.01). CONCLUSION: We conclude that, for superficial surgical procedures of up to 120 minutes, maintenance of anesthesia with propofol impairs early postoperative lung function and pulse oximetry values more than with desflurane. Furthermore, increasing obesity decreases pulmonary function at 2 hours after propofol anesthesia but not after desflurane anesthesia.

[Daytime sleepiness in patients with Obstructive Sleep Apnoea (OSA) - pathogenetic factors]. / Tagesschläfrigkeit bei obstruktiver Schlafapnoe (OSA) - pathogenetische Faktoren.

Excessive daytime sleepiness (EDS) is one of the most frequent symptoms in patients with obstructive sleep apnoea (OSA). EDS can lead to substantial impairments in quality of life and is a major cause of fatal accidents. However, not all patients with OSA develop EDS. The aim of this paper is to review the current literature to identify factors having an impact on sleepiness in patients with OSA. Interestingly, a substantial heterogeneity of the results was found. Summarising these results, causes of EDS in patients with OSA are multifactorial. Severity of obesity and breathing disorders (apnoea/hypopnoea index) seem to be the most important predictors. Continuous positive airway pressure therapy significantly reduces sleepiness in patients with OSA.

[Sleep-disordered breathing in long-term opioid therapy]. / Schlafbezogene Atmungsstörungen bei Opioid-Langzeittherapie.

Chronic opioid use has been known to cause disturbed sleep as well as excessive daytime sleepiness. During induction and maintenance of opioid use there is a reduction of REM- and slow wave sleep. Central sleep apnea (CSA) has been reported in about 30 % of patients with chronic opioid use. Ataxic breathing and CSA are more prominent in NREM- than REM-sleep. CSA does not seem the sole cause of excessive daytime sleepiness in these patients. Further studies are necessary regarding the effects and consequences of chronic opioid use during sleep.

[Risk of interrupting nocturnal nasal continuous positive airway pressure (nCPAP) in patients with obstructive sleep apnea]. / Perioperative Unterbrechung der nächtlichen Uberdruckbeatmung gefährdet Schlafapnoe-Patienten.

Patients with obstructive sleep apnea are at risk of respiratory and cardiovascular complications (e.g. hypoxia, hypertensive crisis, cardiac ischemia and arrhythmias) as a result of airway callapse during the perioperative period. Therefore it is essential that the nasal continuous airway pressure (nCPAP-therapy) be maintained during that time. Such patients and the medical staff should be aware of this problem.

[Long-term opioid therapy and respiratory insufficiency during sleep]. / Chronische Morphintherapie und respiratorische Insuffizienz im Schlaf.

An increasing proportion of the patients with chronic pain are being treated with opioids on a long-term basis. There are indications that the causes of hypersomnia in patients under chronic opioid therapy are primarily related to breathing disorders during sleep. Hence, we compared the polysomnographies of three hypersomnic patients receiving long-term opioid therapy before and during nocturnal non-invasive ventilatory therapy. Significant findings were a central breathing pattern accompanied by reduced deep and REM sleep. On applying non-invasive ventilatory therapy, there was a significant improvement of respiratory status with an increase of deep sleep as well as a moderate decrease in hypersomnia. In patients under chronic opioid therapy with hypersomnia, the presence of central breathing disorders should be considered.

Effect of intra-operative pressure support vs pressure controlled ventilation on oxygenation and lung function in moderately obese adults.

Obesity impairs peri-operative lung function. To evaluate the impact of pressure support ventilation vs pressure controlled ventilation in moderately obese adults upon early postoperative lung function, we randomly assigned 68 moderately obese patients (body mass index 25-35 kg x m(-2)) undergoing minor surgery to receive intra-operative ventilation either with pressure support or pressure controlled ventilation. We performed intra-operative blood gas analysis and measured pulse oximetry saturation, spirometry values at pre-operative assessment (baseline) and at 10 min, 30 min, 2 h and 24 h after extubation. The intra-operative oxygenation index (arterial partial pressure of oxygen/fraction of inspired oxygen) in the pressure support ventilation group was significantly improved over time (p < 0.0001). Postoperatively, the pressure support ventilation group also had better lung function and oxygenation values than did the pressure controlled ventilation group (p < 0.005). We conclude that pressure support ventilation better maintains lung function than pressure controlled ventilation in moderately overweight patients scheduled for minor surgery.

[Perioperative management of patients suffering from sleep-related breathing disorders]. / Perioperatives Management bei Patienten mit schlafbezogenen Atmungsstörungen.

Sleep-related breathing disorders have been associated with increased perioperative morbidity and mortality. The respective patients are at risk during two independent periods. Besides an early period, characterised by the influence of anaesthetics, patients are at risk also during a late period, which is characterised by nocturnal desaturation and disturbances of the cardiovascular system, caused by interference with the sleep architecture, especially of the REM sleep. To assure a safe perioperative management, a close monitoring (O2 saturation and pCO2) and the option for non-invasive ventilation have to be guaranteed.

[Wheezing during normal breathing as a sign of bronchial obstruction]. / Giemen bei Ruheatmung als Zeichen bronchialer Obstruktion.

Wheezing is a clinical feature in patients with chronic obstructive airway diseases. Long-term monitoring of wheezing could provide a new dimension of diagnostic information as compared to lung function if wheezing really does represent airway obstruction. Patients with wheezing who were part of our Marburg Respiratory Sound Database (MARS) were studied. 20 patients with asthma and 17 patients with chronic obstructive pulmonary disease (COPD) were analysed with respect to pathological changes of lung function parameters. The patients were matched with persons without wheezing in regard to age, diagnosis and sex. Additionally, 58 healthy persons with normal lung function tests were analysed for the occurrence of spontaneous wheezing during normal breathing. In patients with wheezing, at least one parameter of lung function was pathological. For asthmatic patients significant differences for MEF (50) (p = 0.011), R (tot) (p = 0.002) and Tiffeneau (p = 0.001) were found. In patients with COPD significant differences for FEV (1) (p = 0.002) and MEF (50) (p = 0.030) were found. In none of the healthy persons with normal lung function did we find wheezing. Wheezing as a clinical sign of bronchial obstruction is useable for long-term monitoring. The method provides additional information that can help to monitor nocturnal asthma.

[Obscure coughing and the feeling of suffocation during sleep. Long-term nocturnal acoustic recording]. / Unklarer Husten und Erstickungsgefühl im Schlaf. Nächtliche akustische Langzeitregistrierung.

A 58-year old male presented with a 6-week history of increasing nocturnal cough, dyspnea and awakening. Physical examination, chest auscultation and lung function in the daytime did not show any pathological findings. Only nocturnal long-term recording of respiratory sounds was helpful: In- and expiratory wheezing, as the acoustic manifestation of airway obstruction, was found throughout the night. As the cause for nocturnal cough and distinct airway obstruction, a pansinusitis with postnasal drip syndrome was diagnosed.