Electrical stimulation of the whole hypoglossal nerve in patients with obstructive sleep apnea.

PURPOSE: Electrical stimulation of the whole hypoglossal nerve (HGp-ES) has been demonstrated to enlarge the pharynx and improve pharyngeal stability and patency to airflow in all animals studied, but not in humans. The present study was undertaken to better understand the effect of HGp-ES on the human pharynx. METHODS: Eight patients with obstructive sleep apnea who had implanted stimulators with electrodes positioned proximally on the main truck of the hypoglossus were studied under propofol sedation. Pharyngoscopy and air flow measurements at multiple levels of continuous positive airway pressure (CPAP) were performed before and during Hgp-ES. RESULTS: HGp-ES that activates both tongue protrusors and retractors narrowed the pharyngeal lumen at the site of collapse (velopharynx in all subjects) from 1.38 ± 0.79 to 0.75 ± 0.44 cm2, p < 0.05 (measured at mid-range of CPAP levels) and lowered airflow (from 8.88 ± 2.08 to 6.69 ± 3.51 l/min, p < 0.05). Changes in critical pressure (Pcrit) and velopharyngeal compliance were not significant, but oropharyngeal compliance decreased (from 0.43 ± 0.18 to 0.32 ± 0.13 cm2/cmH2O, p < 0.05). No correlation was found between the pattern of change in luminal shape (determined as the ratio of a-p vs. lateral diameter when lowering CPAP) or changes in cross-sectional area and airflow during Hgp-ES. CONCLUSIONS: Our findings indicate that human retractors dominate when stimulated together with the protrusors during HGp-ES. While co-activation of retractors may be beneficial, it should be limited. We speculate that exercises that augment protrusor force may improve the response to hypoglossal stimulation. The exclusion of patients with concentric pharyngeal obstruction should be re-evaluated.

Guías y algoritmos para el manejo de la vía aérea difícil / Guidelines and algorithms for managing the difficult airway

La vía aérea difícil constituye un continuo desafío para el anestesiólogo y su tratamiento es una de las tareas de mayor exigencia al representar un riesgo vital. Las guías y algoritmos juegan un papel clave en la preservación de la seguridad del paciente al recomendar planes y estrategias específicos para abordar la vía aérea difícil prevista o inesperada. Sin embargo, no existen actualmente algoritmos «de referencia», ni estándares universalmente aceptados. El objetivo de este artículo es presentar una síntesis de las recomendaciones de las principales guías y algoritmos de la vía aérea difícil (AU)

The difficult airway constitutes a continuous challenge for anesthesiologists. Guidelines and algorithms are key to preserving patient safety, by recommending specific plans and strategies that address predicted or unexpected difficult airway. However, there are currently no "gold standard" algorithms or universally accepted standards. The aim of this article is to present a synthesis of the recommendations of the main guidelines and difficult airway algorithms (AU)

Guidelines and algorithms for managing the difficult airway. / Guías y algoritmos para el manejo de la vía aérea difícil.

The difficult airway constitutes a continuous challenge for anesthesiologists. Guidelines and algorithms are key to preserving patient safety, by recommending specific plans and strategies that address predicted or unexpected difficult airway. However, there are currently no "gold standard" algorithms or universally accepted standards. The aim of this article is to present a synthesis of the recommendations of the main guidelines and difficult airway algorithms.

Does adding intravenous fentanyl to caudal block in children enhance the efficacy of multimodal analgesia as reflected in the plasma level of catecholamines?

BACKGROUND AND OBJECTIVE: Several studies showed that single analgesic modality management can attenuate perioperative stress, but little is known about the effect of multimodal analgesia on catecholamine responses to surgical trauma in children. METHODS: Fifty children (American Society of Anesthesiologists Grade I or II) were randomly allocated to one of two groups: one received general anaesthesia and a caudal block (control group), and one group was given general anaesthesia, caudal block and intravenous (i.v.) fentanyl 2 microg kg(-1) (fentanyl group). Plasma epinephrine and norepinephrine concentrations were measured three times during the perioperative period: at induction time (T(0)), at the end of surgery (T(1)) and when the children were fully awake in the postanaesthesia care unit (T(2)). RESULTS: There was a significant reduction in the catecholamine levels in the two groups when (T(1)) and (T(2)) were compared with T(0). When plasma epinephrine levels (at T(0), T(1) and T(2)) between the two groups were compared, a statistically significant reduction at T(2) was obtained in the fentanyl group, when compared with the control group. However, plasma norepinephrine levels showed no statistically significant difference between the two groups (at T(0), T(1) and T(2)). CONCLUSION: These findings suggest that the multimodal analgesic approach of adding i.v. low-dose fentanyl to a caudal block may decrease the plasma epinephrine release in children undergoing inguinal herniotomy.

Changes in creatine phosphokinase (CK) concentrations after minor and major surgeries in children.

BACKGROUND: During surgery, damage occurs to muscles in the area of the operation. The few studies that have examined creatine phosphokinase (CK) values after surgery have been in adults. The only study in children was after cardiac surgery. Understanding the normal enzyme pattern of change may help to differentiate malignant hyperthermia, anaesthesia-induced rhabdomyolysis and elevated CK values resulting from inherited muscle disease in cases in which these are suspected. The aim of this study was to delineate the normal rise of CK after minor and major surgery in children. METHODS: A total of 71 patients aged 1 month-17 yr were studied. From the cohort of 71 patients, 46 underwent elective surgery (14 major, 32 minor) and in 25 the surgery was designated as an emergency surgery (21 major, 4 minor). The anaesthesia protocol was similar for both groups with halothane induction and isoflurane maintenance. Owing to its possible effect on CK, succinylcholine was avoided during the study. RESULTS: The mean values of CK concentration before and after surgery were 63.1 iu litre(-1) and 151.5 iu litre(-1), respectively. The median CK elevation (range) for the major and minor surgery groups was 43 iu litre(-1) (4-647) and 10 iu litre(-1) (-28 to 122), respectively (P<0.0001). CONCLUSIONS: CK concentrations in the major surgery group were significantly higher than the minor surgery group. This profile can contribute to the evaluation of patients who present with the possibility of malignant hyperthermia, anaesthesia-induced rhabdomyolysis and underlying muscle disease. Any rise of CK concentration above what is expected should prompt further investigation.

Acupuncture versus ondansetron in the prevention of postoperative vomiting. A study of children undergoing dental surgery.

This study compares the anti-emetic effect of acupuncture with that of ondansetron and a placebo. Ninety children undergoing dental treatment under general anaesthesia were randomly allocated to one of the three equal groups, to receive acupuncture needle insertion, intravenous ondansetron 0.15 mg x kg(-1) or a placebo. Parental satisfaction scores and the incidence of emetic episodes were recorded. A significant difference was found in the number of patients who vomited and the total number of the emetic episodes when comparing the two treatment groups with the placebo group (p < 0.0001). A significant difference was also found between the treatment groups and the placebo group with respect to parental satisfaction score (p < 0.03). We conclude that traditional Chinese acupuncture is a valid non-pharmacological alternative anti-emetic treatment that can be recommended as a prophylactic technique in children undergoing dental surgery under general anaesthesia.

The influence of preemptive spinal anesthesia on postoperative pain.

STUDY OBJECTIVE: To examine the influence of spinal anesthesia on postoperative pain and postoperative opioid requirements. DESIGN: Prospective randomized study. SETTING: Bnai-Zion Medical Center, Haifa, Israel-a government hospital. MEASUREMENTS AND MAIN RESULTS: 30 ASA physical status I and II unpremedicated women undergoing elective total abdominal hysterectomy were randomly allocated into two groups of 15 patients each using a sealed envelope technique. Patients in Group 1 were given a subarachnoid injection of 12 mg hyperbaric bupivacaine and after 10 minutes general anesthesia was induced. Patients in Group 2 received only general anesthesia. Anesthesia was induced with midazolam and maintained with oxygen, N2O, isoflurane, and pancuronium. No opioids were given intraoperatively. Postoperatively patient-controlled analgesia (PCA) with morphine was initiated in both groups (1 mg x mL(-1), bolus dose 1 mg, lockout interval 10 minutes, and background infusion 1 mg x mL(-1)) at patient first request for analgesic. Pain was assessed over 24 hours by cumulative morphine dose and visual analog score (VAS). Postoperative PCA morphine consumption at 2, 6, and 24 hours following patient first request for analgesic for Groups 1 and 2 were: 3.1 +/- 1 mg versus 7.2 +/- 3 mg (p = 0.04), 13.4 +/- 2 mg versus 17.2 +/- 4 mg (p = 0.03) and 35.9 +/- 8 mg versus 47.7 +/- 8 mg in Group 2 (p = 0.04). VAS scores at 4, 6, 12, and 24 hours postoperatively were not significantly different between the two groups. CONCLUSIONS: Preoperative neural blockade may reduce postoperative analgesic requirements.

Pneumomediastinum due to Venturi jet ventilation used during microlaryngeal surgery in a previously neck-irradiated patient.

Serious complications secondary to Venturi jet ventilation used during microlaryngoscopy are rare, but when they occur, they may pose a life-threatening emergency. We report the case of a 45-year-old woman, previously treated with 70 Gy of irradiation for a T1 laryngeal carcinoma, who developed pneumomediastinum and subcutaneous emphysema after the use of Venturi jet ventilation. Keeping in mind the histologic changes to the irradiated structures, we suggest more caution when using Venturi jet ventilation in patients who have recently undergone neck irradiation therapy.

Does the addition of fentanyl to bupivacaine in caudal epidural block have an effect on the plasma level of catecholamines in children?

We evaluated the effect of adding fentanyl to bupivacaine, compared with bupivacaine alone, on the stress response. The effect was evaluated by determining blood levels of epinephrine (E) and norepinephrine (NE) in pediatric patients receiving caudal epidural blocks. Sixty children, 1-8 yr of age, scheduled for elective herniorrhaphy, were randomly allocated to two groups of 30 patients each. Group A received inhaled anesthesia and caudal epidural block with bupivacaine 0.25% alone, 1.0 mL/kg. Group B received identical anesthesia; however, fentanyl 1 microg/kg was added to the bupivacaine in the caudal block. Blood samples for E and NE plasma levels were drawn at induction time (H(0)), at the end of surgery (H(1)), and in the postanesthesia care unit (H(2)). In both groups, there was a significant decrease in the E and NE plasma levels, when comparing H(1) and H(2) with H(0) within the same group (P < 0.001). There were no significant differences in the E and NE plasma levels between the two groups at H(0), H(1), and H(2) (P = 0.5, P = 0.12, P = 0.5, respectively). Pain scores (modified Children's Hospital of Eastern Ontario Pain Score) were also similar in both groups (P = 0. 19). This study suggests that adding fentanyl 1 microg/kg to bupivacaine in the caudal epidural block in children does not influence plasma levels of E and NE, nor does it improve the analgesic intensity of the caudal block.

Using rate-based events to improve clinical practice.

This article describes the implementation and utilization of a continuous quality improvement (CQI) program in the identification, analysis, and correction of a rate-based event in anesthesia, in this case, intraoperative hypertension. A CQI program was implemented based on voluntary, handwritten, anonymous reports of intraoperative and postanesthesia care unit events. This CQI program detected a high incidence of intraoperative hypertension, indicated major causal factors, suggested a set of corrective measures, and allowed for measurement of their efficacy.

Effect of caudal block on the plasma adrenaline and noradrenaline concentrations in paediatric patients undergoing ilioinguinal herniorrhaphy.

This study compared the effect of two anaesthetic techniques on the catecholamine levels in children undergoing ilioinguinal herniorrhaphy. Forty male paediatric patients ASA class I were allocated randomly to one of two groups: the control group (n = 20) received general anaesthesia including intravenous fentanyl; and the caudal group (n = 20) received caudal anaesthesia with bupivacaine 0.25% 1 mL kg-1 combined with general anaesthesia but without opioids. Plasma adrenaline and noradrenaline concentrations were measured at induction, at the end of surgery and in the post-anaesthesia care unit (PACU). In the caudal group, there were significant decreases in the adrenaline and noradrenaline concentrations at the end of surgery and in the PACU compared with baseline concentrations. In the control group, there was a significant increase in PACU concentrations of adrenaline and noradrenaline compared with baseline concentrations. These findings suggest that the addition of a caudal block to general anaesthesia in children undergoing ilioinguinal herniorrhaphy decreases significantly the neurohormonal responses to surgery.

Fiberoptic-guided airway exchange of the esophageal-tracheal Combitube in spontaneously breathing versus mechanically ventilated patients.

UNLABELLED: The aim of this study was to compare fiberoptic-guided airway exchange of the esophageal-tracheal Combitube (ETC, Kendall-Sheridan Catheter Corp., Argyle, NY) with an endotracheal tube in spontaneously breathing versus mechanically ventilated patients. Forty patients with Mallampati score III and IV scheduled for elective surgery were randomly allocated into two groups (n = 20 each): nonparalyzed, spontaneously breathing or paralyzed, mechanically ventilated patients. After anesthetic induction and insertion of the ETC, a fiberoptic bronchoscope threaded into an armored endotracheal tube was passed transnasally into the larynx. Endotracheal intubation was successful in 18 spontaneously breathing patients and in 15 patients during controlled ventilation. Successful airway exchange was completed in significantly less time (P < 0.05) in spontaneously breathing patients (9+/-3 min; mean +/- SD) than in mechanically ventilated patients (13+/-4 min). Both methods allowed for continuous airway control and maintenance of ventilation and oxygenation. The described method is a means of replacing the ETC with an endotracheal tube without interruption of airway control or ventilation. Replacing the ETC with an endotracheal tube using this method is more readily accomplished during spontaneous ventilation than during controlled ventilation. IMPLICATIONS: We describe the replacement of the Combitube by an endotracheal tube by the aid of fiberoptic bronchoscopy and without interruption of airway control or ventilation. The performance of this technique was facilitated by spontaneous ventilation compared with mechanical ventilation.

Replacing the combitube by an endotracheal tube using a fibre-optic bronchoscope during spontaneous ventilation.

We present a case of microlaryngoscopy in a patient with an unexpectedly difficult airway. The airway was managed by using an oesophageal-tracheal Combitube (Kendall-Sheridan, Argyle, NY) (ETC) and a fibre-optic bronchoscope (Pentax-Japan-5 mm).

Postoperative outcome in high-risk infants undergoing herniorrhaphy: comparison between spinal and general anaesthesia.

The incidence of inguinal hernia is higher in premature infants, particularly in low birth weight neonates. This latter group may also incur increased postoperative respiratory complications and inpatient admissions. The purpose of this study was to compare the effects of general and spinal anaesthesia on postoperative respiratory morbidity and on the length of hospital stay in high-risk infants undergoing inguinal herniorrhaphy. Forty patients, all high-risk infants who underwent unilateral or bilateral herniorrhaphies, were randomly assigned to receive general anaesthesia (n = 20) or spinal anaesthesia (n = 20). There was a significant difference in respiratory morbidity between the two groups, as well as a significant difference in the inpatient hospital stay. The present study suggests that spinal anaesthesia can be used safely for high-risk infants, preterm or formerly preterm, undergoing inguinal hernia repair.

Failure to control the airway in a patient with Hunter's syndrome.

Hunter's syndrome is due to recessively inherited mucopolysaccharide storage diseases. The anaesthetic complications in this syndrome are related to the organs involved in the disease, but pertain especially to upper airway obstruction problems. We report a patient with Hunter's syndrome who, while under general anaesthesia for a simple procedure (the introduction of bilateral grommets), suffered a fatal outcome.