Prospective validation of a new airway management algorithm and predictive features of intubation difficulty.

BACKGROUND: Some patients have features that indicate possible difficulty with direct laryngoscopy for tracheal intubation. Prediction of the likely outcome and selection of patients for an enhanced management algorithm would reduce the possible harm from failed intubation attempts. METHODS: Adult elective patients were assessed for seven features associated with difficult direct laryngoscopy, ranked in difficulty from 0 to 3. For a patient with at least one Class 3 feature, or two or more features of class 1 or higher, the enhanced management used a channelled videolaryngoscope Airtraq™ instead of a Macintosh laryngoscope. A long flexible angulated stylet and a flexible fibrescope would be used as the second and third steps. For patients with lesser difficulty scores, a Macintosh laryngoscope was used. Outcomes of enhanced management were analysed. Logistic regression and Random Forest algorithm, using the ranks of the predictive features, were used to predict difficulty during enhanced management. RESULTS: We prospectively studied 16 695 patients. We selected 1501 (9%) for enhanced management, and tracheal intubation was successful in all of them. Of these, 73% were intubated in less than 30 s, and only 4.5% required more than 4 min for intubation. Progression to the second and third steps of enhanced management was predicted by restriction of mouth opening and reduced cervical spine mobility. CONCLUSIONS: An enhanced management algorithm allowed successful tracheal intubation of all patients with anticipated difficult laryngoscopy. The need to combine the use of a stylet and a fibrescope with the Airtraq™ could be predicted with a high degree of certainty.

[THE FIRST EPIDEMIOLOGICAL DATA ABOUT THE HR-HUMAN PAPILLOMA VIRUS TYPES IN SOUTH AND NORTHERN BULGARIA].

The aim of our study were to evaluate the prevalence of HR-HPV infection in women between 15 and 55 years of age in the South and Northern Bulgaria. We have analyzed the HPV status (using DNA-sorb-AM nucleic acid extraction kit) in cervical samples collected during a 3 year period (2010-2012) from 1020 women, aged 15-55 and divided in four age groups, who attended their gynecologists for HPV-DNA cervical test. The rate of the HR-HPV infection was established to be 39.9%. HR-HPV negative were 60.1% of the evaluated subjects. The most commonly isolated genotype in all 407 (100%) infected women was HPV 16 - 190 women (46.7%), followed by HPV 56 - 78 (19.1%), HPV 31- 48 (11.8%) and HPV 33 - 45 (11.1%). To our knowledge, this is the first survey evaluating the prevalence of HR-HPV infection in the South and Northern regions of Bulgarian towns and drawing attention to the unusually high proportion of different HR-HPV.

Postoperative visual loss due to complicated mediastinal dissection and haemorrhagic shock treatment during cardiac surgery.

We report the case of a patient who underwent third time revision of double heart valve replacement. Mediastinal dissection for right atrium cannulation was complicated by laceration of the superior vena cava; this required temporary rescue clamping of the vessel. The patient suffered complete visual loss related to bilateral retrobulbar haematoma. Acute elevation of superior vena cava pressure due to vascular clamping and administration of large amounts of fluid through the central venous jugular catheter could have caused the postoperative visual loss.

Sparing the larynx during gynecological laparoscopy: a randomized trial comparing the LMA Supreme and the ETT.

BACKGROUND: We designed a prospective randomized single-blind study to compare efficiency and post-operative upper airway morbidity when the laryngeal mask airway (LMA) Supreme is used as an alternative to the endotracheal tube (ETT). METHODS: One hundred and thirty-eight elective pelvic laparoscopic ASA I-II female patients were assigned to receive either the LMA Supreme or the ETT for airway management. Balanced anesthesia and ventilation techniques were standardized to control end-tidal CO(2) and BIS value in the range 4.5-5 kPa and 40-50, respectively, and to maintain adequate hemodynamic stability. A single surgeon blinded to the airway management technique performed all surgical procedures. The ventilation efficiency of each airway was evaluated. Anesthesia- and surgery-related times were calculated and anesthesia details were recorded. Post-operative pain and pharyngolaryngeal morbidity were measured in a blind fashion using a numerical rating scale (NRS) (0-100). RESULTS: Surgery duration was similar in both groups. Airway management duration was shorter with the LMA Supreme. Post-operative pharyngolaryngeal morbidity incidence and all symptoms' intensity were significantly increased after ETT as compared with LMA Supreme anesthesia. At the end of the PACU stage, the incidence and mean NRS of post-operative hoarseness were reduced when LMA Supreme was used as an alternative to the ETT (16% vs. 47%; P<0.01 and 9 vs. 19, P<0.01, respectively). CONCLUSION: We demonstrated that choosing an LMA Supreme was an efficient pharyngolaryngeal morbidity-sparing strategy. Moreover, we showed that the LMA Supreme and the ETT were equally effective airways for a routine gynecological laparoscopy procedure.

Long term course of the H reflex after selective tibial neurotomy.

OBJECTIVES: This study was conducted to evaluate the long term clinical and electrophysiological outcome by recording the H reflex in a consecutive series of six patients treated by selective tibial neurotomy for spastic equinus foot. METHOD: The amplitudes of Hmax reflexes, Mmax responses, and Hmax:Mmax ratio were recorded in six patients with chronic lower limb spasticity, before and after surgery, at day 1 and 8 months and 24 months after selective tibial neurotomy. The passive range of movement, the stretch reflex score according to the Tardieu scale, the osteoarticular and tendon repercussions, and the quality of motor control of dorsiflexion were evaluated preoperatively and postoperatively. RESULTS: At the end of the study, all patients presented a reduction of equines. Gait and Tardieu's score of spasticity had improved in all patients. Active dorsiflexion of the ankle was unchanged in four patients, but two improved by 5 degrees to 12 degrees. In five cases, fascicular resection of the superior nerve to soleus was, alone, sufficient to reduce spastic equinus foot, without recurrence, for a mean follow up of 28 months. Two patients were reoperated on, one for remaining spasticity related to an underestimated spasticity of the gastrocnemius muscles, and the other for painful claw toes. Hmax, Mmax, and Hmax:Mmax ratios were significantly lower the day after surgery. The reduction of Hmax and Hmax/Mmax ratio remained stable over time and was still statistically significant two years after the operation. However, the value of Mmax eight months postoperatively was no longer significantly different from the preoperative value. CONCLUSION: This study shows the long term efficacy of the selective tibial neurotomy as treatment of spastic equinus foot. Neurotomy confined to fibres supplying the soleus muscle is sufficient in most cases and acts by decreasing sensory afferents without significant long term motor denervation.

Soleus neurotomy for treatment of the spastic equinus foot. Groupe d'Evaluation et de Traitement de la Spasticité et de la Dystonie.

OBJECTIVE: This prospective, nonrandomized, noncontrolled study was performed to evaluate the results of a new type of neurotomy, namely the soleus neurotomy, for treatment of the spastic equinus foot. METHODS: Between May 1996 and March 1998, 46 patients were treated for a spastic equinus foot. Clinical status, spasticity (Ashworth Scale score), and kinematic parameters of the gait were determined before and after surgery. The neurotomy was performed on the upper nerve of the soleus in all cases and was associated with other neurotomies (lower nerve of the soleus, 21 patients; gastrocnemius, 9 patients, tibialis posterior, 18 patients; flexor hallucis longus, 16 patients; and flexor digitorum longus, 17 patients). RESULTS: The mean follow-up period was 15 months (range, 8-28 mo). The equinus deformity disappeared clinically in all patients. Before the operation, all patients had an Ashworth Scale score of 2, with an inexhaustible clonus present on knee extension and persisting with knee flexion (Tardieu Scale score, 4), which was abolished in 95% of the patients after surgery. Two patients still had some clonus on knee extension; this did not interfere with their clinical improvement. Knee recurvatum disappeared in eight patients. Analysis of kinematic parameters demonstrated a statistically significant increase in joint motion of the second rocker (P = 0.0026) of the ankle during stance. The duration of the stance or swing phase, length of the walking cycle, and velocity or rate of spontaneous walking were not significantly modified. CONCLUSION: The study demonstrated that soleus neurotomy is effective for the treatment of spastic equinus foot, leading to abolition of spasticity and improvement in the range of ankle motion during the stance phase of gait.

Pharmacokinetics and pharmacodynamics of rapacuronium in patients with cirrhosis.

BACKGROUND: Delayed elimination kinetics of steroidal neuromuscular blocking agents have been observed in patients with cirrhosis. Like other steroidal muscle relaxants, rapacuronium may, in part, be eliminated by the liver. To determine the influence of liver disease on its neuromuscular blocking effect, we studied the pharmacokinetics and pharmacodynamics of rapacuronium in patients with cirrhosis. METHODS: Sixteen patients undergoing elective surgery or endoscopy with general anesthesia, eight with cirrhosis and eight with normal liver function, were studied. Anesthesia was induced with fentanyl 2 microg/kg and thiopental 5-7 mg/kg and maintained with 60% nitrous oxide and 0.6-0.8% isoflurane in oxygen and repeated doses of fentanyl 1 microg/kg. Rapacuronium 1.5 mg/kg was administered intravenously before tracheal intubation. Thumb adduction force evoked by supramaximal ulnar nerve stimulation was recorded in 16 patients. Venous blood was sampled at frequent intervals for 8 h. Rapacuronium and its breakdown product Org 9488 were measured in plasma by high-pressure liquid chromatography. Values are reported as median (range). RESULTS: The central volume of distribution was increased to 131 (104-141) ml/kg in patients with cirrhosis (P < 0.01), compared with 75 (47-146) ml/kg in controls. The total apparent volume of distribution was also increased (P < 0.05) to 331 (284-488) ml/kg in patients with cirrhosis, compared with 221 (124-285) ml/kg in controls. The elimination half-life was 88 (77-102) min in controls and 90 (76-117) min in patients with cirrhosis. Plasma clearance was increased (P < 0.05) to 6.9 (6.1-8.9) ml x min(-1) x kg(-1) in patients with cirrhosis, compared with 5.3 (4.2-8.4) ml x min(-1) x kg(-1) in controls. Rapacuronium neuromuscular blocking effect was similar between the two groups. Onset time was 65 (40-110) s in controls and of 60 (52-240) s in patients with cirrhosis. Time to return to 90% of thumb adduction force control value was of 49 (28-80) min in controls and 47 (28-71) min in patients with cirrhosis. CONCLUSION: The neuromuscular blocking effect of a single bolus dose of rapacuronium in patients with cirrhosis is not different from that of patients with normal hepatic function. No decrease in plasma clearance of rapacuronium was observed in patients with cirrhosis.

Effects of an intubating dose of succinylcholine and rocuronium on the larynx and diaphragm: an electromyographic study in humans.

BACKGROUND: Paralysis of the vocal cords is one objective of using relaxants to facilitate tracheal intubation. This study compares the neuromuscular blocking effect of succinylcholine and rocuronium on the larynx, the diaphragm, and the adductor pollicis muscle. METHODS: Electromyographic response was used to compare the neuromuscular blocking effect of succinylcholine and rocuronium on the laryngeal adductor muscles, the diaphragm, and the adductor pollicis muscle. Sixteen patients undergoing elective surgery were anesthetized with propofol and fentanyl, and their tracheas were intubated without neuromuscular blocking agents. The recurrent laryngeal and phrenic nerves were stimulated at the neck. The electromyographic response was recorded from electrodes placed on the endotracheal tube and intercostally before and after administration of 1 mg/kg succinylcholine or 0.6 mg/kg rocuronium. RESULTS: The maximum effect was greater at the adductor pollicis (100 and 99%) than at the larynx (96 and 97%) and the diaphragm (94 and 96%) after administration of succinylcholine and rocuronium, respectively (P < or = 0.05). Onset time was not different between the larynx (58+/-10 s), the diaphragm (57+/-8 s), and the adductor pollicis (54+/-13 s), after succinylcholine (all mean +/- SD). After rocuronium, onset time was 124+/-39 s at the larynx, 130+/-44 s at the diaphragm, and 115+/-21 s at the adductor pollicis. After succinylcholine administration, time to 90% recovery was 8.3+/-3.2, 7.2+/-3.5, and 9.1+/-3.0 min at the larynx, the diaphragm, and the adductor pollicis, respectively. Time to 90% recovery after rocuronium administration was 34.9+/-7.6, 30.4+/-4.2, and 49.1+/-11.4 min at the larynx, the diaphragm, and the adductor pollicis, respectively. CONCLUSION: Neuromuscular blocking effect of muscle relaxants on the larynx can be measured noninvasively by electromyography. Although the larynx appears to be resistant to muscle relaxants, we could not demonstrate that its onset time differed from that of peripheral muscles.

Comparison of the effects of mivacurium on the diaphragm and geniohyoid muscles.

Although subjects often report difficulty with swallowing shortly after receiving neuromuscular blocking agents, difficulty with swallowing during recovery from neuromuscular blocking agents appears to be infrequent. We have used electromyography to compare onset and recovery at the diaphragm and geniohyoid airway muscles after an intubating dose of mivacurium (0.2 mg kg-1) to determine if the geniohyoid muscles were particularly sensitive to neuromuscular blocking agents. Twelve adults undergoing elective surgery were anaesthetized with propofol and fentanyl and the trachea intubated without neuromuscular blocking agents. The left hypoglossal and right phrenic nerves were stimulated with percutaneous needle electrodes and the electromyogram recorded with surface electrodes. EMG responses were measured after a bolus dose of mivacurium 0.2 mg kg-1. Recordings were also made of the mechanical response of the adductor pollicis to supramaximal ulnar nerve stimulation. There was no difference in the rate of onset of block for geniohyoid muscles and the diaphragm, but recovery to 25% and 90% of the control response was shorter at the diaphragm (median 14.5 (95% confidence limits 12.9-15.3) min and 23.8 (21.7-26) min) than at the geniohyoid muscle (19.4 (15.6-20.1) min and 29.2 (26.3-31.4) min), respectively (P < 0.05). When the train-of-four ratio of the mechanical response of the thumb reached 70%, the diaphragm and geniohyoid muscles had recovered completely in all patients.

Comparison of duration of neuromuscular blocking effect of atracurium and vecuronium in young and elderly patients.

In a controlled, randomized study, we evaluated duration of neuromuscular block in 80 patients undergoing routine abdominal surgery. Forty patients were aged 18-50 yr (control group) and 40 patients were more than 65 yr (elderly group). All patients had normal plasma creatinine concentrations. After induction of anaesthesia, patients were allocated randomly to receive either atracurium 0.5 mg kg-1 or vecuronium 0.1 mg kg-1 to facilitate tracheal intubation. Monitoring of the evoked response of the adductor pollicis muscle to supramaximal single twitch ulnar nerve stimulation every 10 s was performed and measured with a strain gauge. Repeat doses of atracurium 0.1 mg kg-1 or vecuronium 0.02 mg kg-1 were administered when the adductor pollicis response recovered to 25% of the control twitch height. We found that the duration of action of the initial dose of atracurium was similar in the control and elderly groups, and it did not vary after repeated doses. However, the initial dose of vecuronium caused a significantly longer period of clinical block in the elderly group compared with the controls, and the duration of action of repeated doses was longer in the elderly group. We conclude that as there is a risk of prolonged effect of vecuronium in the elderly, monitoring of neuromuscular function is recommended in this group. Alternatively, atracurium should be preferred for prolonged surgery in elderly patients.

Comparison of the neuromuscular blocking effect of atracurium and vecuronium on the adductor pollicis and the geniohyoid muscle in humans.

BACKGROUND: Residual paralysis of suprahyoid muscles may occur when the adductor pollicis response has completely recovered after the administration of a neuromuscular blocking agent. The response of the geniohyoid muscle to intubating doses of muscle relaxants is evaluated and compared to that of adductor pollicis. METHODS: Sixteen patients undergoing elective surgery under general anesthesia were given 5-7 mg.kg-1 thiopental and 2 micrograms.kg-1 fentanyl intravenously for induction of anesthesia. Eight (half) patients then received 0.5 mg.kg-1 atracurium, and the other eight received 0.1 mg.kg-1 vecuronium. The evoked response (twitch height, TH) of the adductor pollicis was monitored by measuring the integrated electromyographic response (AP EMG) on one limb and the mechanical response, using a force transducer (AP force), on the other. The activity of geniohyoid muscle (GH EMG) was measured using submental percutaneous electrodes. The following variables were measured: maximal TH depression; onset time for neuromuscular blockade to 50%, 90%, and maximal TH depression (OT50, OT90, and OTmax); times between administration of neuromuscular blocking agent and TH recovery to 10%, 25%, 50%, 75%, and 90% of control; and time for return of train-of-four ratio to return to 0.7. RESULTS: The principal findings were (1) OTmax was significantly (P < 0.01) shorter for geniohyoid than for adductor pollicis after either atracurium or vecuronium (OTmax was 216, 256, and 175 s for AP force, AP EMG, and GH EMG, with atracurium and 181, 199, and 144 s with vecuronium, respectively), and (2) the evoked EMG of geniohyoid recovered at the same speed as the EMG of adductor pollicis after an intubating dose of atracurium or vecuronium (recovery of TH to 75% of control at 50, 48, 42 min with AP force, AP EMG, and GH EMG with atracurium and 46, 45, and 42 min with vecuronium, respectively). CONCLUSIONS: Once the adductor pollicis response has returned to normal values after a single intubating dose of atracurium or vecuronium, the risk of residual depression of the TH of the geniohyoid muscle, one of the principal muscles contributing to airway patency, appears unlikely.

[Intraoperative anaphylactic shock following the percutaneous puncture of a hepatic echinococcal cyst]. / Intraoperativen anafilaktichen shok sled perkutanna punktsiia na chernodrobna ekhinokokova kista.

This is a report on a case of severe intraoperative anaphylactic shock, developing within several hours of percutaneous puncture of a liver hydatid cyst, performed under echographic control, necessitating recovery from the shock state and discontinuation of the operative intervention. Inferences are reached regarding the most adequate treatment tactics to be adopted in handling such cases. Percutaneous puncture is discarded as a therapeutic approach because of the great risk of anaphylaxis with eventual lethal outcome, and the likelihood of severe abdominal echinococcosis development at a later period.

Pharmacokinetics and pharmacodynamics of rocuronium in patients with cirrhosis.

BACKGROUND: Rocuronium, like other steroidal nondepolarizing muscle relaxants, may in part be eliminated by the liver. To determine the influence of liver disease on its neuromuscular blocking effect, we studied the pharmacokinetics and pharmacodynamics of rocuronium in patients with cirrhosis. METHODS: Eighteen patients undergoing elective surgery, 10 with cirrhosis and 8 with normal liver function, were studied. Anesthesia was induced with intravenous thiopental 5-7 mg.kg-1 and maintained with 60% nitrous oxide in oxygen and repeated doses of fentanyl 2 micrograms.kg-1. The force of thumb adduction in response to supramaximal ulnar nerve stimulation was monitored and recorded. An intravenous bolus of rocuronium 0.6 mg.kg-1 was administered and venous blood sampled at frequent intervals for 6 h. Plasma concentrations of rocuronium was measured by high-pressure liquid chromatography. Data were fitted to both a pharmacokinetic and a pharmacodynamic model by using a two-compartment open model and an effect compartment model. Data were analyzed by least-squares regression. RESULTS: The onset of neuromuscular blockade was longer (P < 0.01) in patients with cirrhosis (158 +/- 56 s) than in normal patients (108 +/- 33 s). Recovery of the thumb twitch to 75 and 90% of its control value was 77 +/- 25 and 88 +/- 29 min in cirrhotic patients versus 57 +/- 11 and 64 +/- 13 min, respectively, in normal patients (P < 0.05). The central volume of distribution of rocuronium was 104 +/- 21 in cirrhotic patients and 78 +/- 24 ml.kg-1 in normal patients (P < 0.05). No significant difference in elimination kinetics was observed between the two groups. The elimination half-life was 87.5 +/- 17.5 min in normal patients and 96.0 +/- 36.8 min in cirrhotic patients (difference not significant). This increased onset time was linearly correlated to the increased central volume of distribution of rocuronium in cirrhosis. CONCLUSION: Rocuronium onset time is longer in cirrhotic patients than in those with normal liver function; this can be explained by an increase in the volume in which rocuronium initially distributes. Although elimination kinetics are unchanged in patients with cirrhosis, rocuronium recovery time is prolonged in cirrhotic patients.