Thomas Mencke

Laryngeal Morbidity and Quality of Tracheal Intubation: A Randomized Controlled Trial

Background Vocal cord sequelae and postoperative hoarseness during general anesthesia are a significant source of morbidity for patients and a source of liability for anesthesiologists. Several risk factors leading to laryngeal injury have been identified in the past. However, whether the quality of tracheal intubation affects their incidence or severity is still unclear. Methods Eighty patients were randomized in two groups (n = 40 for each) to receive a propofol–fentanyl induction regimen with or without atracurium. Intubation conditions were evaluated with the Copenhagen Score; postoperative hoarseness was assessed at 24, 48, and 72 h by a standardized interview; and vocal cords were examined by stroboscopy before and 24 and 72 h after surgery. If postoperative hoarseness or vocal cord sequelae persisted, follow-up examination was performed until complete restitution. Results Without atracurium, postoperative hoarseness occurred more often (16 vs. 6 patients;P = 0.02). The number of days with postoperative hoarseness was higher when atracurium was omitted (25 vs. 6 patients;P < 0.001). Similar findings were observed for vocal cord sequelae (incidence of vocal cord sequelae: 15 vs. 3 patients, respectively, P = 0.002; days with vocal cord sequelae: 50 vs. 5 patients, respectively, P < 0.001). Excellent intubating conditions were less frequently associated with postoperative hoarseness compared to good or poor conditions (11, 29, and 57% of patients, respectively; excellent vs. poor:P = 0.008). Similar findings were observed for vocal cord sequelae (11, 22, and 50% of patients, respectively; excellent vs. poor:P = 0.02). Conclusions The quality of tracheal intubation contributes to laryngeal morbidity, and excellent conditions are less frequently associated with postoperative hoarseness and vocal cord sequelae. Adding atracurium to a propofol–fentanyl induction regimen significantly improved the quality of tracheal intubation and decreased postoperative hoarseness and vocal cord sequelae.

Airway injuries after one-lung ventilation: A comparison between double-lumen tube and endobronchial blocker : A randomized, prospective, controlled trial

Background:Vocal cord injuries, postoperative hoarseness, and sore throat are common complications after general anesthesia. One-lung ventilation can be achieved via two techniques: double-lumen endotracheal tube or endobronchial blocker such as the Arndt blocker. The current study was designed to assess the impact of these techniques for one-lung ventilation on the incidence and severity of postoperative hoarseness, vocal cord lesions, and sore throat. Methods:In this prospective trial, 60 patients were randomly assigned to two groups. One-lung ventilation was achieved with either an endobronchial blocker (blocker group) or a double-lumen-tube (double-lumen group). Postoperative hoarseness and sore throat were assessed at 24, 48, and 72 h after surgery. Bronchial injuries and vocal cord lesions were examined by bronchoscopy immediately after surgery. Results:In 56 included patients, postoperative hoarseness occurred significantly more frequently in the double-lumen group compared with the blocker group: 44% versus 17%, respectively (P = 0.046). Similar findings were observed for vocal cord lesions: 44% versus 17%, respectively (P = 0.046). The incidence of bronchial injuries was comparable between groups (P = 0.540). Cumulative number of days with hoarseness and sore throat were significantly increased in the double-lumen group compared with the blocker group (P < 0.01). No major complications such as bronchial ruptures were observed. Conclusions:Clinicians should be aware of an increased incidence of minor airway injuries that may impair patient satisfaction when using a double-lumen tube instead of an endobronchial blocker for one-lung ventilation.

Does the timing of tracheal intubation based on neuromuscular monitoring decrease laryngeal injury? A randomized, prospective, controlled trial

Vocal cord injuries (VCI) and postoperative hoarseness (PH) are common complications after general anesthesia. Poor muscle relaxation at the moment of tracheal intubation may result in VCI. There is a large interindividual variation in neuromuscular depression after administration of neuromuscular blocking drugs. Therefore, the optimal individual timing of tracheal intubation based on neuromuscular monitoring (monitoring) may decrease VCI. In this prospective trial, 60 patients were randomized into 2 groups: Monitoring group: tracheal intubation at maximum block based on monitoring after atracurium 0.5 mg/kg and 2-min group: tracheal intubation 2 min after injection of atracurium 0.5 mg/kg. Intubating conditions were evaluated with the Copenhagen score. VCI were examined by stroboscopy before and 24 and 72 h after surgery. PH was assessed at 24, 48, and 72 h after surgery by a standardized interview. Excellent intubating conditions were significantly increased in the monitoring group compared with the 2-min group: 8 versus 2 patients, respectively (P = 0.036). The incidence of PH between the study groups was comparable: 7 (monitoring) versus 8 patients (2-min) (P = 0.860). Similar findings were observed for VCI: 9 versus 5 patients; respectively (P = 0.268); type of VCI: thickening of the vocal cords: 8 (monitoring) versus 5 (2-min) patients (P = 0.423), hematomas: 2 patients in each group (not significant). The present study demonstrated that neuromuscular monitoring improved endotracheal intubating conditions. However, tracheal intubation at maximum intensity of neuromuscular block was not associated with a decrease in vocal cord injuries.

Laryngeal Complications After Thyroidectomy: Is It Always the Surgeon?

HYPOTHESIS Laryngeal dysfunction after thyroidectomy is a common complication. However, few data are available to differentiate whether these complications result from injury to the recurrent nerve or to the vocal folds from intubation. SETTING University medical center. PATIENTS Seven hundred sixty-one patients who underwent surgery to the thyroid gland from 1990 to 2002. Of these patients, 8.4% underwent a revision thyroidectomy. INTERVENTION Preoperative and postoperative laryngostroboscopic examination. MAIN OUTCOME MEASURE Laryngostroboscopic evaluation of laryngeal complications. RESULTS The overall rate of laryngeal complications was 42.0% (320 patients). Complications from an injury to the vocal folds occurred in 31.3% of patients. Weakness or paresis of the recurrent nerve was initially present in 6.6% and was related to the nerves at risk. This rate was higher in revision thyroidectomies than in primary surgical interventions (6.2% vs 11.6%; P = .04). The rate of laryngeal injuries was higher in patients older than 65 years (39.8% vs 30.8%; P = .03). CONCLUSIONS These data suggest that laryngeal complications after thyroidectomies are primarily caused by injury to the vocal folds from intubation and to a lesser extent by injury to the laryngeal nerve. We recommend documentation of informed consent, especially for patients who use their voice professionally, such as singers, actors, or teachers.

The influence of residual neuromuscular block on the incidence of critical respiratory events. A randomised, prospective, placebo-controlled trial.

Context Residual paralysis is associated with post-operative pulmonary complications, including critical respiratory events. Objective We determined the incidence of critical respiratory events, such as hypoxaemia, in patients with minimal residual neuromuscular blockade and compared these data with those from patients with full recovery of blockade. Design Randomised, prospective, placebo-controlled trial. Setting Single centre; Rostock, Germany, from January 2007 to February 2008. Patients One hundred and thirty-two adult patients, aged 18–80 years, with the American Society of Anesthesiology I–III physical status, undergoing orthopaedic surgery under general anaesthesia, including rocuronium to produce neuromuscular blockade; 114 patients were randomised to one of two groups: neostigmine group (neostigmine 20 &mgr;g kg−1) or placebo group (saline). Interventions In the patients in the neostigmine group, the tracheal tube was removed at a train-of-four (TOF) ratio of 1.0; in the patients in the placebo group, the trachea was extubated at a TOF ratio less than 1.0, but without fade in TOF and double-burst stimulation (DBS). Neuromuscular monitoring was assessed simultaneously with qualitative TOF/DBS monitoring, and with quantitative calibrated acceleromyography. Critical respiratory events, such as hypoxaemia, were assessed in the post-anaesthesia care unit. Main outcome measures Forty-five patients (39.5%) became hypoxaemic (SaO2 < 93%); there was a significant difference between the groups (29 patients in the placebo group versus 16 in the neostigmine group; P = 0.021). Results In the neostigmine group, all patients were extubated at a TOF ratio of 1.0. In the placebo group, the median TOF ratio was 0.7 (range: 0.46–0.9; P < 0.001). The median time for spontaneous recovery in the placebo group was 16 min (range 3–49 min). Neostigmine 20 &mgr;g kg−1 was effective in antagonising rocuronium-induced blockade without fade in TOF and DBS. Conclusion In this randomised, prospective, placebo-controlled trial, minimal residual block was associated with hypoxaemia in the post-anaesthesia care unit. Neostigmine 20 &mgr;g kg−1 was effective in antagonising rocuronium-induced (minimal) blockade.

Rocuronium is not associated with more vocal cord injuries than succinylcholine after rapid-sequence induction: a randomized, prospective, controlled trial.

Postoperative hoarseness (PH), sore throat (ST), and vocal cord injuries (VCI) are common complications after general anesthesia. Excellent endotracheal intubating conditions are associated with less laryngeal morbidity than good or poor intubating conditions. Thus, we tested the hypothesis that a rapid-sequence induction (RSI) with succinylcholine would lead to less PH and VCI than with rocuronium. In this prospective trial, 160 patients were randomized in 2 groups to receive thiopental 5.0 mg/kg, fentanyl 3.0 &mgr;g/kg, succinylcholine 1.0 mg/kg, or rocuronium 0.6 mg/kg during RSI. PH and ST were assessed at 24, 48, and 72 h after surgery, VCI were examined by stroboscopy in those patients who had PH >3 days. Excellent and clinically acceptable intubating conditions were significantly increased in the succinylcholine group compared with the rocuronium group: 57% versus 21% and 89% versus 59%, respectively (P < 0.001). The incidence and severity of PH, and VCI between the succinylcholine and the rocuronium groups did not differ significantly: PH: 50% versus 51% (P = 0.99) and VCI: 3% versus 1% (P = 0.98), respectively. Similar findings were found for ST, 39% versus 28% (P = 0.22), and postoperative myalgia, 39% versus 29% (P = 0.25), respectively. Intubating conditions were significantly better in the succinylcholine group compared with the rocuronium group. The incidence and severity of ST and myalgia were not increased in the patients receiving succinylcholine. However, the rate of PH and VCI was similar to the rocuronium group.

Therapeutic Effect of Intrathecal Morphine After Posterior Lumbar Interbody Fusion Surgery: A Prospective, Double-blind, Randomized Study

Study Design. Prospective, double-blind, randomized, placebo-controlled study. Objective. To assess the efficacy and safety of 0.4 mg intrathecal morphine for postoperative pain control after posterior lumbar interbody fusion (PLIF) surgery. Summary of Background Data. Multiple studies have established the technique of intrathecal morphine analgesia in a wide variety of clinical settings. Several trials were conducted in patients undergoing spine surgery, generally supporting the efficacy for this type of surgery. Many exhibit methodologic problems with dosing regimes or study design. Methods. After the institutional review board-approval and written informed consent, 52 patients scheduled for PLIF-surgery were enrolled, of whom 46 could be analyzed. Patients were randomized to receive 0.4 mg morphine (M-group) or normal saline (P-group) intrathecally under direct vision before the end of surgery. Additionally, all patients received a piritramide patient-controlled-analgesia for individual pain control. Measures included visual analog scale-scores and blood-gas analysis over 20 hours after surgery. Morphine associated side effects and complications were recorded. Results. Visual analog scale-scores at rest and when the patients bent their legs were comparable between groups throughout the observation period, only being significantly lower in the M-group at rest 4 and 8 hours after surgery. Cumulative piritramide patient-controlled-analgesia requirements were significantly lower in the M-group throughout the observed 20 hours after surgery. Patients of the M-group were experiencing mild respiratory depression 4 hours after surgery not demanding any intervention, though. With respect to other morphine associated side effects or complications, there was no difference between the study groups. Conclusion. We demonstrated the efficacy of 0.4 mg intrathecal morphine after PLIF-surgery as indicated by a significantly lower cumulative piritramide requirement without any serious increase of opioid associated side effects. Therefore, morphine in a dose of 0.4 mg administered intrathecally seems to be a viable alternative therapeutic option to provide postoperative analgesia with PLIF-surgery.

Effect of a 0.5% Dilution of Propofol on Pain on Injection during Induction of Anesthesia in Children

Background:Pain on injection of propofol in children has been reported to be as high as 30–80%. The reason for the pain is assumed to be the aqueous phase of the propofol emulsion. Therefore, for the first time, this study tested the hypothesis that dilution of propofol to a 0.5% emulsion might reduce the incidence of pain during propofol injection. Methods:The study design was prospective, monocenter, double-blind, and randomized. Sixty-four children aged 2–6 yr were scheduled to receive 0.5% or 1.0% propofol in a medium-chain-triglyceride/long-chain-triglyceride emulsion. Incidence and intensity of pain were assessed by spontaneous expressions of pain and withdrawal of the arm. In a subgroup of 21 children, serum triglyceride levels were measured before and 3 and 20 min after induction. Adverse events were recorded. Results:Amounts of propofol required until loss of eyelash reflex were 4.40 ± 1.01 mg/kg for 0.5% propofol and 4.31 ± 0.86 mg/kg for 1.0% propofol. Percentages of children who showed at least one pain reaction were 23.3% in the 0.5% propofol group and 70.0% in the 1.0% propofol group (P < 0.001). Serum triglycerides were higher in the 0.5% propofol group 3 and 20 min after injection (251.7 vs. 148.8 mg/dl; P = 0.001 and 135.5 vs. 75.5 mg/dl; P = 0.03). Adverse events or complications did not occur. Conclusions:Dilution of propofol to a 0.5% medium-chain-triglyceride/long-chain-triglyceride emulsion reduced pain effectively during injection in children aged 2–6 yr. Cumulative doses until 4–5 mg/kg propofol led to moderate increases of triglyceride levels and did not result in significant adverse events.

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.

Einfluss des Geschlechts auf den Verlauf der neuromuskulären Blockade nach Rocuronium

ZusammenfassungFragestellung. Die pharmakodynamische Wirkung zahlreicher Anästhetika und Adjuvanzien wird auch durch das Geschlecht der Patienten beeinflusst. Ziel der vorliegenden Studie war es zu untersuchen ob es zwischen männlichen und weiblichen Patienten Unterschiede im Verlauf der neuromuskulären Blockade von 0,45 mg/kg Rocuronium (1,5 × ED95) gibt. Methodik. Mittels Elektromyographie wurde an jeweils 20 weiblichen (Gruppe A) und 20 männlichen Patienten (Gruppe B) der zeitliche Verlauf der neuromuskulären Blockade und die maximale Muskelblockade nach 0,45 mg/kg Rocuronium untersucht. Ergebnisse. Die Patientinnen waren 38 (±8) Jahre, die Patienten 37 (±10) Jahre alt (n.s.). In Gruppe A betrug der body mass index (BMI) 24,2 (±2,9)kg/m2, in Gruppe B 25,2 (1,7) kg/m2; n.s. Die männlichen Patienten waren signifikant schwerer und größer als die weiblichen Patienten: 77,5 (±5,5) kg vs. 65,7 (±9,3) kg; p<0,01 und 178 (±6,8) cm vs. 164 (±6,7) cm; p<0,01. Verglichen mit den männlichen Patienten war die Anschlagzeit von Rocuronium bei den weiblichen Patienten im Mittel 43 s kürzer (211 (±56) s vs. 168 (±65) s, p<0,05). Das Ausmaß der maximalen Blockade nach 0,45 mg/kg Rocuronium betrug in Gruppe A 94 (±3)% (Spannbreite: 89%–100%); in Gruppe B hingegen war die maximale neuromuskuläre Blockade signifikant geringer ausgeprägt: 89 (±6)% (Spannbreite 74%–97%); (p<0,01). Die Wirkdauer war bei Frauen signifikant länger als bei Männer (23 (±5) min vs. 17 (±5) min, p<0,05); der Erholungsindex war hingegen in beiden Gruppen vergleichbar: 9 (±4) min vs. 9 (±3) min (n.s.); Tabelle 2. Schlussfolgerung. In der vorliegenden Untersuchung kam es nach 0,45 mg/kg Rocuronium bei Frauen zu einer deutlich ausgeprägteren neuromuskulären Blockade als bei Männern. Dies zeigte sich sowohl in einer größeren maximalen Muskelblockade als auch in einer kürzeren Anschlagzeit und einer längeren Wirkdauer.AbstractBackground. We studied 40 patients (20 female and 20 male) undergoing elective surgery under general anaesthesia to evaluate the effect of gender on the pharmacodynamics of rocuronium. Methods. Using electromyography (EMG) we determined the maximal neuromuscular block and time course of action of 0.45 mg/kg rocuronium (1.5×ED95). Results. Age and body mass index were comparable between females and males (38 (±8) vs. 37 (±10) years and 24.2 (±2.9) vs. 25.2 (±1.7) kg/m2. However, significant differences in weight and height were found between females and males (65.7±9.3 kg vs. 77.5±5.5 kg; p<0.01 and 178±6.8 cm vs. 164±6.7 cm; p<0,01). Onset time was shorter in females (168±65 s vs. 211±56 s; p<0.05). Maximal neuromuscular blockade after 0.45 mg/kg rocuronium was 94 (±3) % in females and 89 (±6) % in males; p<0.01. Clinical duration was increased in females (23±5 min vs. 17±5 min; p<0.05), while the recovery index was comparable between both groups (9±4 min in females and 9±3 min in males; n.s.). Conclusion. Compared to men neuromuscular blockade after 0.45 mg/kg rocuronium was more pronounced in women. The onset time was shortened and the clinical duration increased in female patients.