[New aspects of rapid sequence induction including treatment of pulmonary aspiration]. / Neue Aspekte der "rapid sequence induction" einschließlich Behandlung der pulmonalen Aspiration.

Pulmonary aspiration of solid components leads to displacement of the tracheobronchial tree, the aspiration of acidic gastric juices to chemical pneumonitis (Mendelson's syndrome) and the aspiration of oropharyngeal secretions or gastrointestinal pathogens to aspiration pneumonia. Principally, pulmonary aspiration can occur at any stage of anesthesia. In the clinical routine the aim must therefore be to identify those patients who have an increased risk of aspiration. When this is successful, measures can be taken to reduce the risk; these can be regional anaesthesia or the performance of general anaesthesia as rapid sequence induction (RSI). If severe pulmonary aspiration occurs despite all preventive measures, mostly during induction of anaesthesia, extensive experience and rapid action are necessary. This can only be achieved if the induction to RSI is performed by three persons with supervision of the trainee anaesthetist by a consultant anaesthetist.

[Influence of rocuronium dose on the effectiveness of mask ventilation : A prospective, randomized clinical trial]. / Der Einfluss der Rocuroniumdosis auf die Effektivität der Maskenbeatmung : Eine prospektive, randomisierte, klinische Studie.

BACKGROUND: Mask ventilation could improve after administration of muscle relaxants if there is a functional obstruction of the airway, such as laryngospasm, vocal cord closure or opioid-induced muscle rigidity. On the other hand, muscle relaxants could worsen mask ventilation because they induce upper airway collapse; however, clinical studies showed that rocuronium (Roc) improved mask ventilation or it remained unchanged. In most cases Roc 0.06 mg/kgBW was used. OBJECTIVE: The optimal dose of Roc has not been studied; therefore, we studied the quality of mask ventilation with three different doses of Roc (0.3, 0.6 and 0.9 mg/kgBW) and compared them with a control group receiving saline. MATERIAL AND METHODS: In this prospective clinical trial 200 patients were randomized into 4 groups: NaCl (saline), Roc03 (Roc 0.3 mg/kgBW), Roc06 (Roc 0.6 mg/kgBW) and Roc09 (Roc 0.9 mg/kgBW). Mask ventilation was performed to reach a tidal volume (TV) of >5.0 ml/kgBW; maximum ventilation peak pressure (ppeak) was limited to 25 mbar. If this TV was not reached, mask ventilation was improved by better mask position, head position or/and usage of a Guedel tube (oropharyngeal airway). During mask ventilation ppeak and TV were recorded and the quality of mask ventilation was assessed with the Han and Warters scores. The quality of mask ventilation between the four groups was compared for all patients and a subgroup analysis was performed for patients of the study groups, who had to be ventilated with a Guedel tube and for obese patients (body mass index ≥26 kg/m2). A sample size calculation revealed that at least 38 patients were necessary for each group to detect a statistically significant difference between groups; it was assumed that Roc improved the efficacy of mask ventilation by 20% compared to saline (α = 0.05, 1-ß = 0.8). RESULTS: The administration of Roc significantly improved the TV/ppeak ratio compared to saline (p = 0.04); however, this effect was irrespective of the dose. In patients who were ventilated with the Guedel tube the TV/ppeak ratio increased after Roc03 (p ≤ 0.01) and after Roc06 (p < 0.02) compared to the saline group. In obese patients who were ventilated with the Guedel tube the TV/ppeak ratio increased after Roc03 (p ≤ 0.01), after Roc06 (p = 0.03) and after Roc09 (p = 0.02) compared to the saline group. There were no significant differences between the Roc groups; however, the effect was more pronounced in the Roc03 patients compared to the other Roc groups. The Han and Warters scores were not significantly different between the Roc groups and the saline group. CONCLUSION: The efficacy of mask ventilation was equal or improved after administration of Roc but did not become worse. Patients who were ventilated with a Guedel tube had higher TV/ppeak ratios after Roc03 and Roc06 compared to saline. Higher dosages (>Roc06), however, had no advantages concerning quality of mask ventilation. In obese patients who had to be ventilated with a Guedel tube, Roc also improved the efficacy of mask ventilation. We conclude that administration of Roc is effective in improving mask ventilation and this effect was seen after 30-60 s even after Roc03.

[Certain and controversial components of "rapid sequence induction"]. / Sichere und kontroverse Komponenten der "rapid sequence induction".

Rapid sequence induction (RSI) is a specific technique for anesthesia induction, which is performed in patients with an increased risk for pulmonary aspiration (e.g. intestinal obstruction, severe injuries and cesarean section). The incidence of acute respiratory distress syndrome (ARDS) is very low but 10-30% of anesthesia-related deaths are caused by the consequences of ARDS. The classical RSI with its main components (i.e. head-up position, avoidance of positive pressure ventilation and administration of succinylcholine) was published nearly 50 years ago and has remained almost unchanged. The modified RSI consists of mask ventilation before endotracheal intubation is performed or the use of non-depolarizing muscle relaxants. Succinylcholine 1.0 mg/kg or rocuronium 1.0-1.2 mg/kg should be administered to achieve excellent intubation conditions. The use of cricoid pressure was a cornerstone of RSI after its introduction in 1961; however, after controversial discussions in recent years, cricoid pressure has lost its importance. Before surgery gastric emptying with a nasogastric tube is mandatory in patients with ileus and passage or defecation disorders.

[Neuromuscular monitoring]. / Neuromuskuläres Monitoring.

The effect of muscle relaxants varies among people and the extent, the duration and recovery from the neuromuscular block varies. Clinical tests cannot determine the effect of muscle relaxants which is only possible with neuromuscular monitoring. The relaxometry procedure measures the muscular response to electrical stimulation of the corresponding motor nerve and the adductor pollicis muscle is mostly used; however, this muscle is not representative for other muscle groups, such as the muscles of the larynx and diaphragm. The muscles of the larynx and diaphragm are more resistant against nondepolarizing muscle relaxants than the adductor pollicis muscle. The train of four (TOF) is used at the beginning of surgery for monitoring of the optimal time for tracheal intubation; moreover, the TOF is used during surgery for monitoring of the muscle blockade and at the end of surgery for monitoring recovery. Monitoring of deep muscular blockades, however, is only possible with the posttetanic count (PTC) when there are no TOF counts. The PTC allows repetition and higher doses of muscle relaxants during abdominal surgery; therefore, conditions for surgery are optimal and cumulation of muscle relaxants is avoided.

[Laryngeal alterations following endotracheal intubation and use of larynx masks]. / Laryngeale Veränderungen nach endotrachealer Intubation und Anwendung der Larynxmaske.

After endotracheal intubation patients most frequently report pharyngolaryngeal complaints. Subsequent impairment of vocal performance might lead to general impairment of communication and job-related performance. Most prevalently, swollen mucosa, hematomas, granuloma and edema in the larynx can be observed after intubation. Limitations of respiratory vocal fold mobility appear less frequently. Knowledge of the pathophysiological aspects and causative factors associated with laryngopharyngeal morbidity are essential cornerstones of quality assurance in perioperative respiratory tract management. This review describes the effects of endotracheal intubation and application of larynx masks in relation to laryngeal morbidity.

Attenuation of a rocuronium-induced neuromuscular block in patients receiving prednisolone.

BACKGROUND: This study tested the influence of continuous medication (more than 4 weeks) with prednisolone on a rocuronium-induced neuromuscular block. METHODS: The time course of a rocuronium-induced neuromuscular blockade (0.3 mg/kg) was investigated in 40 patients with chronic inflammatory bowel disease undergoing elective abdominal surgery. The primary end point was the time from the start of injection of rocuronium until recovery of the TOF ratio to 0.9. Twenty patients received continuous medication with prednisolone (group A), and 20 were without glucocorticoid medication (group B). Additionally, another 20 patients without inflammatory bowel disease and without glucocorticoid medication served as control (group C). RESULTS: The onset time was prolonged in group A [253 (51.2) s] compared with group B [187 (61.3) s]. Twitch height at the onset of the block was higher in group A [16.5 (0-61)%] than that in group B [5.0 (0-33)%]. The duration to 25% twitch height was shorter in group A [12.6 (0-20.7) min] compared with group B [16.7 (0-25.3) min] and group C [16.9 (0-29.3) min]. The recovery to a train-of-four ratio of 0.9 was reduced in group A [25.7 (23-34.3) min] compared with group B [34.7 (32.7-44.2) min] and group C [36.5 (31.7-42.3) min]. CONCLUSIONS: Prednisolone treatment in patients with inflammatory bowel disease is associated with a delayed onset and a shorter duration of action of rocuronium. The presence of an inflammatory bowel disease did not influence the neuromuscular block.

Are women more sensitive to a pre-curarization dose of rocuronium than men?

BACKGROUND: There is increasing evidence that there are gender-related differences in the pharmacodynamics of neuromuscular blocking drugs. However, it is not known whether gender influences the pharmacodynamics of a pre-curarizing dose. METHODS: In the first part, we measured the neuromuscular blockade after administration of rocuronium 0.03 mg/kg (10% of ED(95)) after induction of anaesthesia in 20 patients (10 female and 10 male patients) by electromyography. In the second part, 40 female and 40 male patients were observed for signs and symptoms of muscle weakness 2.5 min after injection of rocuronium 0.03 mg/kg before loss of consciousness. Succinylcholine-associated post-operative myalgia (POM) was also assessed. RESULTS: Median twitch heights were comparable between the two groups: 95.5 (range: 85-97; female) vs. 96.0 (range: 85-99; male), (NS). Train-of-four ratios were 97.5 (range: 64-100; female) vs. 99.0 (range: 52-100; male) (NS). Signs and symptoms of muscle weakness were observed in 64 (80%) patients, but there were no gender-related differences. The incidence and severity of POM did not differ significantly between the study groups. CONCLUSIONS: Pre-curarization with rocuronium 0.03 mg/kg affected men and women equally. Nor was the incidence and the severity of muscle weakness affected by gender.

Influence of a continuous prednisolone medication on the time course of neuromuscular block of atracurium in patients with chronic inflammatory bowel disease.

BACKGROUND: Corticosteroids interact with neuromuscular blocking agents. However, experimental data are contradictory: enhancement and attenuation of the neuromuscular block has been observed. This study tested the influence of long-term medication with prednisolone on atracurium-induced neuromuscular block. METHODS: Sixty patients with chronic inflammatory bowel disease undergoing elective abdominal surgery were investigated. Thirty patients received a long-term medication with prednisolone (Group A) and 30 were without corticoid medication (Group B). Additionally, another 30 patients without inflammatory bowel disease and without corticoid medication served as control (Group C). The following parameters of an atracurium-induced neuromuscular block (0.25 mg kg(-1)) were measured: onset time, maximum block, recovery to 25% first twitch height, recovery index (time from 25% until 75% recovery of first twitch), duration to recovery to a train-of-four (TOF) rate of 0.7 and 0.9. RESULTS: The groups did not differ with regard to onset time, maximum block, and recovery index. The duration to 25% twitch height was significantly lower in Group A [18.1 (0-30.7) min] compared with Group B [23.5 (0-36.7) min; P<0.05]. Duration to a TOF rate of 0.7 and 0.9, respectively, were significantly reduced in Group A [36.1 (7.9) and 40.9 (9.0 min)] compared with Group B [47.9 (7.6) and 53.4 (9.2) min; P<0.001]. CONCLUSIONS: Long-term medication with prednisolone resulted in a shorter duration of an atracurium-induced neuromuscular block in patients with Crohn's disease or ulcerative colitis. The presence of the inflammatory bowel disease did not influence the time course of the neuromuscular block.

[Intra-articular bupivacaine following hip joint arthroscopy. Effect on postoperative pain]. / Intraartikuläre Bupivacaingabe bei Hüftgelenkarthroskopie. Effekt auf postoperative Schmerzen.

The effect of intra-articular bupivacaine on postoperative pain following arthroscopy has been intensively studied for the knee joint but no data are currently available for the hip joint. The aim of the present prospective, randomized and double-blind study was to evaluate a possible effect of intra-articular bupivacaine on postoperative pain intensity following hip arthroscopy. A total of 26 patients were included: 13 received 20 ml of 0.25% bupivacaine through the trocar at the end of surgery and 13 patients received 20 ml of 0.9% NaCl as placebo. Postoperative pain intensity was assessed using a visual analogue scale (VAS) at 0.5 h, 4 h, 8 h, 12 h, 16 h and 20 h, at rest and during movement of the joint and on the basis of additional piritramide requirements. Furthermore, a mean VAS was calculated as the arithmetic mean of all VAS scores assessed over the whole study period. In the bupivacaine group, a significantly lower mean VAS was recorded at rest (17.5 vs 27.5, p=0.05) and during movement of the hip joint (23 vs. 46, p=0.001). The additional piritramide consumption tended to be higher in the placebo group. In conclusion, intra-articular bupivacaine following arthroscopic hip surgery reduces pain in the postoperative period mainly during movement and thus may possibly allow earlier mobilization.

Effect of propofol on seizure-like phenomena and electroencephalographic activity in children with epilepsy vs children with learning difficulties.

There is an ongoing debate as to whether propofol exhibits pro- or anticonvulsant effects, and whether it should be used in patients with epilepsy. We prospectively assessed the occurrence of seizure-like phenomena and the effects of intravenous propofol on the electroencephalogram (EEG) in 25 children with epilepsy (mean (SD) age: 101 (49) months) and 25 children with learning difficulties (mean (SD) age: 52 (40) months) undergoing elective sedation for MRI studies of the brain. No child demonstrated seizure-like phenomena of epileptic origin during and after propofol sedation. Immediately after stopping propofol, characteristic EEG changes in the epilepsy group consisted of increased beta wave activity (23/25 children), and suppression of pre-existing theta rhythms (11/16 children). In addition, 16 of 18 children with epilepsy and documented EEG seizure activity demonstrated suppression of spike-wave patterns after propofol sedation. In all 25 children with learning difficulties an increase in beta wave activity was seen. Suppression of theta rhythms occurred in 11 of 12 children at the end of the MRI study. In no child of either group was a primary occurrence or an increase in spike-wave patterns seen following propofol administration. The occurrence of beta wave activity (children with learning difficulties and epilepsy group) and suppression of spike-wave patterns (epilepsy group) were transient, and disappeared after 4 h. This study demonstrates characteristic, time-dependent EEG patterns induced by propofol in children with epilepsy and learning difficulties. Our data support the concept of propofol being a sedative-hypnotic agent with anticonvulsant properties as shown by depression of spike-wave patterns in children with epilepsy and by the absence of seizure-like phenomena of epileptic origin.

Does preoperatively administered parecoxib prevent succinylcholine-associated myalgia? A randomized, placebo-controlled trial.

BACKGROUND AND OBJECTIVE: Data from several studies implicate that pre-treatment with non-selective cyclooxygenase inhibitors such as aspirin or diclofenac may decrease the incidence of postoperative succinycholine-related myalgia. We tested the influence of a preoperatively administered selective cyclooxygenase 2 inhibitor, parecoxib, on postoperative myalgia. METHODS: After Ethics Committee approval, 68 patients were randomized into two groups (n = 34 each). Group 1 received parecoxib 40 mg intravenously 3 min before induction of anaesthesia, and Group 2 received saline (in a double-blinded manner). Incidence and severity of myalgia was evaluated systematically with a standardized questionnaire 24, 48 and 72 h after anaesthesia. We also the assessed the number of patients who felt limited in their activity due to myalgia. RESULTS: Seven patients in the parecoxib-treated group complained of myalgia compared with 11 in the control group (not significant). No significant difference in the severity of myalgia or in the limitation of patients activity was found between the groups. CONCLUSION: Intravenous parecoxib 40 mg, when administered before induction of anaesthesia, did not reduce incidence and severity of postoperative myalgia and did not improve activity in those who suffered from myalgia.

[Influence of gender on the intubation conditions with rocuronium]. / Einfluss des Geschlechts auf die Intubationsbedingungen nach Rocuronium.

PURPOSE: There is increasing evidence for gender differences in the pharmacokinetics and pharmacodynamics of anaesthetic drugs and neuromuscular blocking agents, e.g. rocuronium (Roc). Females require 30% less Roc than males to achieve the same degree of neuromuscular block and onset times are shorter. However, whether this leads to an improvement of the intubation conditions in females is unclear. METHODS: After approval of the ethics committee 60 female and 60 male patients were each randomised into 2 groups to receive 0.6 mg/kg body weight Roc or 1.0 mg/kg succinylcholine (Sux; control group). Induction: thiopentone (5 mg/kg), fentanyl (3 microg/kg) then Roc (Roc groups) or Sux (Sux groups) and tracheal intubation after 60 s. Time to intubation, glottic exposure and intubating conditions were assessed. RESULTS: Men were significantly larger and heavier (p<0.001) than women, but the body mass index was comparable (ns). Number of attempts, time to intubation, and Cormack grades were comparable (ns). However, the rate of clinically acceptable intubation conditions was significantly higher in the female compared to the male Roc group: 80% vs 47%, p<0.05. The incidence of clinically acceptable intubation conditions in the female Roc and Sux groups were similar (80%). CONCLUSION: The intubation conditions after Roc were significantly better in women than in men. The differences were Roc-related and did not occur in the control groups.

Women report more pain on injection of a precurarization dose of rocuronium: a randomized, prospective, placebo-controlled trial.

BACKGROUND: The purpose of this study was to investigate whether gender influences the perception of pain on injection of rocuronium. METHODS: In this prospective, placebo-controlled trial 120 patients were randomized into four groups to receive rocuronium 0.03 mg kg(-1) (40 female and 40 male patients) or saline (20 female and 20 male patients). The incidence and severity of the injection pain after administration of the study drug was compared between female and male patients using a numerical rating scale (0-10). Signs of local irritation, i.e. erythema and thrombophlebitis, were assessed up to 48 h after surgery. RESULTS: In 26 (32.5%) of the 80 patients receiving rocuronium, pain on injection was observed. This occurred significantly more frequently in the female compared with male patients: 18 (45%) vs. eight (20%), respectively (P = 0.032). The severity was more pronounced in the women than in the men (P = 0.020). The incidence of the rocuronium-associated pain was significantly increased compared with the Saline groups (P < 0.001). After surgery no patient complained of any residual pain and no local signs were observed in any patient during the study period. CONCLUSIONS: Women experienced more pain on injection of rocuronium than men, moreover this is an additional evidence for gender-related differences in pain perception. When rocuronium is used as a precurarization agent, an analgesic pretreatment (e.g. opioids) should be considered, especially for female patients.

[Precurarization of succinylcholine with cisatracurium: the influence of the precurarization interval]. / Präkurarisierung von Succinylcholin mit Cisatracurium Der Einfluss des Präkurarisierungsintervalls.

PURPOSE: To determine the influence of two different pretreatment intervals, i.e. 3 and 6 min, on the efficacy of 0.01 mg/kg cisatracurium in preventing succinylcholine-induced fasciculations and myalgia. METHODS: A total of 60 adult patients were randomized and received either 0.01 mg/kg cisatracurium (0.2*ED(95)) i.v. (Cis 3 group: pretreatment interval 3 min, Cis 6 group: pretreatment interval 6 min) or normal saline i.v. (placebo group) prior to injection of succinylcholine. The incidence and severity of fasciculations and myalgia and side-effects of precurarization were assessed. RESULTS: The incidence of muscle fasciculations was only reduced in the Cis 6 group (45%) compared with the Placebo group (85%), p<0.05. Cisatracurium was associated with a higher incidence of paralytic symptoms in both pretreatment groups (Cis 3: 75%, Cis 6: 80%) compared with the Placebo group (30%), p<0.05. CONCLUSION: Cisatracurium is only effective in preventing succinylcholine-induced fasciculations when a longer pretreatment interval, i.e. 6 min instead of 3 min, is chosen. Precurarization led to signs of paralysis in both pretreatment groups in the majority (75-80%) of patients without reducing the incidence or severity of postoperative myalgia.

[Neuromuscular blockade with cisatracurium in infants andchildren. Its course under sevoflurane anesthesia]. / Neuromuskuläre Blockade mit Cisatracurium bei Säulingen und Kindern. Verlauf unter Sevoflurananästhesie.

OBJECTIVE: To compare the onset, duration and maximum effect of 0.1 mg/kg cisatracurium during balanced anesthesia with sevoflurane and remifentanil between infants and children. METHODS: We measured the time course of the neuromuscular blockade in 15 infants and 15 children by electromyography. Anesthesia was induced with propofol/remifentanil and maintained with sevoflurane (constant 2% endtidal) and remifentanil according to the patients individual requirements. After injection of 0.1 mg/kg cisatracurium we measured the following parameters: onset time: time between the beginning of injection of cisatracurium and maximum T1 depression, clinical duration: time between injection of the drug and recovery of T1 to 25%, recovery index: time between recovery of T1 from 25% to 75%. TOFR 0.9: time between injection of cisatracurium and recovery of the train-of-four ratio to 90%. In addition, we determined the maximum neuromuscular blockade Tmax after 0.1 mg/kg cistracurium. RESULTS: Both groups differed significantly with regard to onset time and clinical duration. In the infants, the onset time was shorter (74 s vs. 198 s) and the clinical duration longer (55 min vs. 41 min) compared to the older children. The TOFR 0.9 was 73 min (range 56-86 min) in the group of the infants and 59 min (range 43-72 min) in the group of the older children (p < 0.001). Tmax was 100% (range 97-100%) in the infants and 98% (range 92-100%) in the children (p < 0.01). However, the recovery index was comparable in both groups (21 vs. 16 min). CONCLUSIONS: Infants are substantially more sensitive to cisatracurium than children, which can be demonstrated in a significantly shorter onset time, a prolonged clinical duration and a delayed neuromuscular recovery. As there exist large interindividual differences, we recommend the use of neuromuscular monitoring in the routine practice of pediatric anesthesia.