Fu Shan Xue

Assessment of small-dose fentanyl and sufentanil blunting the cardiovascular responses to laryngoscopy and intubation in children.

Background:  The authors found no study assessing the efficacy of small‐dose narcotics on the cardiovascular response from intubation in children, so they observed the effects of fentanyl 2 μg·kg−1 and sufentanil 0.2 μg·kg−1 on the cardiovascular changes during laryngoscopy and intubation in children.

Measures to facilitate the classic laryngeal mask airway guided fiberoptic intubation in children with a difficult airway

0.2 mcgÆkgh and infusing an additional 15 ccÆkg of normal saline. At the end of surgery, hydromorphone 0.02 mgÆkg was administered and the patient was extubated in the operating room. At that time, he was awake and denied having any pain. Five minutes later, blood pressure abruptly increased to 230 ⁄ 120 mmHg, and heart rate to 84 ⁄ min. Sodium nitroprusside infusion was begun at 1 mcgÆkgÆmin and blood pressure was maintained within preoperative range. Patient-controlled analgesia was initiated using intravenous hydromorphone and the patient was transferred to ICU in a stable condition. Sodium nitroprusside was continued until the second postoperative day, when all of his oral antihypertensive medications were restarted. Patients with FD frequently experience paroxysmal dysautonomic crises characterized by severe hypertension, vomiting, rash, and sweating. These are triggered by emotional upset, pain, and other physiological factors that result in increase in levels of circulating catecholamines. In patients older than 15 years of age, supine hypertension and orthostatic hypotension are more commonly seen. One of the most important goals of our anesthetic management was to maintain hemodynamic stability and to prevent dysautonomic crises. We used dexmedetomidine as an anesthetic adjunct based on it’s alpha2-agonist effects, to inhibit central sympathetic discharge. There are reports of perioperative cardiac arrest as a result of severe hypotension in these patients. Various methods for improving cardiovascular stability have been described, including invasive monitoring and the use of vasopressors to treat the hypotension (2). In FD patients with supine hypertension, maintenance of appropriate intravascular volume through adequate volume resuscitation is the key to avoid episodes of severe hypotension. Our patient was admitted overnight to ensure proper hydration and CVP monitoring was used to guide our fluid infusions. Our patient was extubated smoothly at the end of the case. However, we were unable to prevent the abrupt onset of severe hypertension upon greater arousal. It is possible that a higher dose of dexmedetomidine may have been more effective. Axelrod et al. (3) reviewed 81 patients with FD undergoing 727 surgical procedures. They concluded that there is a frequent requirement for postoperative ventilatory support after abdominal surgery when opioids are used for postoperative pain control. Our case illustrates that with the careful titration of short-acting anesthetic agents, use of dexmedetomidine, and the modest doses of opioids, we could provide hemodynamic stability without the need for postoperative ventilatory support. Geeta Gurbuxani Saraiya Neeta Sun Lena Department of Anesthesiology Columbia University 622 West 168th street BHN 4-440 New York NY 10032 USA (email: gg2289@columbia.edu)

Oxygen flush is an effective means to eliminate obscured vision by fogging during intubation using the Airtraq® optical laryngoscope

To the Editor, The Airtraq optical laryngoscope (Airtraq) (Prodol Meditec S.A., Vizcaya, Spain) is a new disposable tracheal intubation device with an anatomically-shaped blade that contains two parallel channels, the optical channel and the guiding channel, which accommodates the endotracheal tube (ETT). The image is transmitted to a proximal viewfinder, and the distal viewing lens allows visualization of the larynx and advancement of the ETT. In addition, the Airtraq has a warming element at the blade tip. According to the manufacturer’s manual, the Airtraq light should be turned on at least 30 sec before use to allow heating of the viewing lens and to prevent fogging. Despite the Airtraq’s anti-fog mechanism, we have observed that visualization of the laryngeal inlet can be obscured by fogging on the viewing lens, especially when tracheal intubation time is prolonged in patients with difficult airways. To resolve this issue, and in view of previous experience with another optical laryngoscope (Truview laryngoscope, Truphatek International Ltd, Netanya, Israel) and the fibreoptic laryngoscopes, we tested the effectiveness of using highflow oxygen to eliminate fogging during laryngoscopy and tracheal intubation using the Airtraq. After receiving local ethics committee approval and written informed consent, we recruited 321 children (aged three months to 17 yr) and 283 adults (aged 18-75 yr) into the study. All of the patients were American Society of Anesthesiologists’ physical status I-II patients who were scheduled for elective plastic surgery in our hospital from March 2009 to June 2010. All procedures called for general anesthesia requiring tracheal intubation. Exclusion criteria included patients with a limited mouth opening that precluded insertion of the Airtraq and refusal to participate in the study. All intubations were performed by anesthesiologists who had been trained in the use of an Airtraq in a short-term airway management program and who had performed tracheal intubations using this device in more than 20 patients prior to this study. Induction and maintenance of anesthesia were not standardized but were left to the discretion of the staff anesthesiologist to use either a propofol or sevofluranebased technique with or without neuromuscular blockade. Before orotracheal intubation, an appropriately-sized ETT was loaded into the guiding channel of the Airtraq, and the ETT tip was positioned at the right side of the viewing lens. When performing nasotracheal intubation, the ETT was inserted via the pre-selected nostril until its tip passed through the posterior naris. The Airtraq was then passed into the patient’s airway over the tongue in the midline. Once the Airtraq blade tip was positioned in the vallecula with the glottis in the centre of the viewfinder, the ETT was passed by the glottis and advanced downwards into the trachea. Obscured vision during laryngoscopy and intubation was defined as fogging on the viewing lens that impeded continuous observation for airway structures and ETT advancement. Whenever this problem occurred, an assistant immediately attached the anesthesia circuit to the ETT. By intermittently pushing the oxygen flush valve of an anesthesia machine, a high oxygen flow was transported via the ETT to the distal end of the Airtraq to eliminate the fogging (Figure). The efficiency of de-fogging was assessed using a three-point scale (inefficient = no Fu Shan Xue, Jian-Hua Liu contributed equally to this work.

Facilitating tracheal intubation in pediatric patients with the Airtraq® optical laryngoscope

To the Editor, The Airtraq optical laryngoscope (Airtraq) (Prodol Meditec S.A., Vizcaya, Spain) is a relatively new disposable tracheal intubation device with an anatomically shaped blade that has two parallel channels, the optical channel and the guiding channel, which accommodates the endotracheal tube (ETT). The Airtraq incorporates a guiding channel to the right of the viewing axis to solve the challenge of passing the ETT through the glottis. However, delivering the ETT through the gap between the end of the guiding channel tube to the glottis may not be straightforward. The guiding channel tube and viewing axis are somewhat incongruent, because the direction of ETT advancement from the guiding channel is defined by the configuration of the guiding channel tube and the ETT angulation. When attempting to advance the ETT through the laryngeal aperture with the Airtraq during tracheal intubation, it has been reported that a posterior tube tip location can be problematic, especially for pediatric patients. On the basis of our cumulated experience with the Airtraq, which includes more than 500 pediatric patients to date, another possible difficulty in advancing the ETT through the glottis, especially in infants and young children with smaller airways, is a left tube tip location. This potential problem arises because the Airtraq is designed with the guiding channel at the right of the viewing axis, and a left-oriented slope at the right side of the distal opening of the guiding channel is devised to direct the tube tip into the glottis in the midline (Figure, Panel A). This design results in ETT advancement from the guiding channel towards the left. Consequently, during advancement of the ETT, the tube tip may move across the midline (Figure, Panel B) towards either the left vocal cord or the left laryngeal vestibule rather than align the ETT towards the midline of the glottis (Figure, Panel C). Whenever this problem arises, our practice has been to withdraw the ETT by approximately 0.5 cm and to exercise one of four available options: 1) slightly rotate the Airtraq in a clockwise direction; 2) advance the Airtraq downwards; 3) gently apply leftwards laryngeal pressure with external laryngeal manipulation, then re-attempt ETT advancement; and 4) in the very rare occasions the above measures fail, withdraw the ETT from the guiding channel and introduce a pediatric bougie into the visualized glottis via the guiding channel. The ETT is then railroaded along the bougie through the larynx, and the Airtraq is used to monitor the progress of the ETT advancement. Over the previous two years, we have used these maneuvers quite successfully to facilitate advancing the ETT into the glottis with the Airtraq device in pediatric patients with uncomplicated and difficult airways alike.

Facilitating endotracheal intubation using the GlideScope® video laryngoscope in children with difficult airways

into the trachea. • If the operator cannot visualize the glottis with or without the epiglottis by the viewfinder, i.e., a grade 3 or grade 4 view of the Airtraq laryngoscope, a pediatric FOB is inserted through the ETT (6). By rotation of the body of the FOB and manipulations of the tip control lever, the glottis is identified and the FOB is inserted into the trachea (Figure 1d). Then, the ETT is advanced over the FOB and inserted into the trachea. Several advantages of this combined use exist. First, the Airtraq laryngoscope can place the ETT tip in the immediate vicinity of the glottis, and the FOB may negotiate the sharp angle between the ETT tip and the glottis. Second, when the FOB operator manipulates it into position, the Airtraq laryngoscope operator may observe the location of the FOB tip by the viewfinder and give verbal feedback to the FOB operator. Third, the Airtraq laryngoscope can be used to monitor the placement of the ETT and find the cause of any resistance to advancement of the ETT over the FOB. F U S. X U E* N O N G H E† J I A N H. L I U* X U L I A O* X I U .Z . X U† Y A N M. Z H A N G* *Department of Anesthesiology Plastic Surgery Hospital Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China †Department of Anesthesiology Shou-Gang Hospital, Peking University Beijing, China (email: fruitxue@yahoo.com.cn)

Endotracheal tube obstruction by unexpected blood clot in anesthetized children: a report of three cases

McGaw, IL, USA) returned a small amount of clear-yellow secretions. ETCO2 and tidal volumes returned to normal. The patient was disconnected from the anesthesia circuit and positioned prone for the procedure. His face was placed on a foam pad (Pediatric Gentletouch 4; Orthopedic Systems, Inc., Union City, CA, USA), and the circuit was reconnected. Shortly after reconnecting the circuit, ETCO2 and tidal volumes decreased to zero, and breath sounds were absent. Positive-pressure ventilation by bag was ineffective. A kink in the tube was suspected, and the patient’s head was repositioned, with no improvement in ventilation. An 8F soft suction catheter was again inserted and upon withdrawal of the catheter, a white foreign body was noted in the endotracheal tube. The foreign body migrated distally with attempts at ventilation, and could not be withdrawn with the 8F catheter. A 10F soft suction catheter was passed, and the foreign body was retrieved. The patient’s oxygen saturation remained above 96% and his heart rate above 100 throughout this time. Tidal volumes and ETCO2 returned to normal, and the rest of the case was uneventful. The foreign body was a 12 · 4 · 5 mm piece of white foam. Upon further inspection, a small gouge in the foam face pad, near the premade passage for the endotracheal tube, was noted and was equal in shape and size to the foreign body. There are numerous case reports of foreign bodies recovered from airways and anesthesia circuits. There are fewer reports of anesthesia equipment obstructing the endotracheal tube. There may be a higher risk with smaller pediatric tubes, as demonstrated by this incident and those cited above. The step of disconnecting and reconnecting the endotracheal tube to the circuit always entails the risk of subsequent complications as the integrity of the circuit is temporarily disrupted. Visual inspection of the circuit should always be undertaken after any disconnection. However, in our situation, only the connector piece of the endotracheal tube was readily visible. The foreign body was initially thought to be a mucus plug, because our patient did have a recent URI and mild ventilatory difficulty at the beginning of the case. Fortunately, positive-pressure ventilation did not push the foam into the bronchial tree, which could have caused more serious complications and required bronchoscopy for retrieval. We are not aware of another instance of this specific complication, despite foam pads being used commonly for surgery in the prone position. Benjamin J . Walker Sally E. Rampersad Department of Anesthesiology and Pain Medicine, University of Washington School of Medicine, Seattle Children’s Hospital, Seattle, WA 98105, USA (email: benjamin.walker@seattlechildrens.org)

Airway anesthesia for awake fiberoptic intubation in management of pediatric difficult airways

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Lightwand guided nasotracheal intubation in children with difficult airways

was maintained with oxygen, air and isoflurane (1.5–2%) and intermittent positive pressure ventilation. Analgesia was supplemented with fentanyl 4 lg and morphine 0.1 mgÆkg in incremental doses. A slight head up tilt, intravenous inj.mannitol 0.25 gÆkg and inj. lasix 1 mg were used to decrease the intracranial pressure. The surgery lasted for 9 h and the patient’s temperature was maintained between 36 and 37 C with an underbody forced air warmer and IV fluid warmer. The intraoperative blood loss was approximately 800 ml, which was replaced with 600 ml of whole blood and 200 ml of fresh frozen plasma. Urine output was 10–20 mlÆkgÆh, which was replaced along with a maintenance fluid (normal saline and ringer lactate). A CVP of 8–10 mm of mercury was maintained during surgery. At the end of the craniofacial surgery, arterial blood gas, coagulation profiles, PCV and serum electrolytes were checked and found to be normal, except for a low serum potassium (2.8 meqÆl), which was treated with potassium supplementation. A subcutaneous drain connected to a small container (Romsons, Nunhai, Agra, India, Minivac Figure 1) was placed and the cranial incision was sutured. The child was re-draped and the ophthalmic surgeon proceeded with enucleation of the left eye. Initially the child was stable but the systolic blood pressure started drifting down over 20 min. Then he had a bradycardia (HR 55 per minute) which was treated with atropine. The heart rate and blood pressure went up followed by severe bradycardia and hypotension. The drapes were removed and it was found that the surgical drain receptacle was full and further drainage was not possible leading to a ‘shiny and tense distended head’ with a marked increase in intracranial pressure. Immediately the scalp sutures were reopened and the venous bleeding controlled. During this period the child lost about 300 ml of blood, which was immediately replaced with intravenous tetra starch 20 mlÆkg, (Voluven, Fresenius Kabi, Pune, India) and blood when it was obtained 30 min later. A repeat coagulation profile was deranged and more Fresh Frozen Plasma was required for correction. Because of this acute episode and the deranged parameters, it was decided not to extubate and the child was shifted to pediatric intensive care unit. Blood loss following craniofacial reconstruction is a known complication (1). In this particular case, blood loss during the surgery was replaced adequately but during the period of enucleation of the eye, blood loss in the surgical drain was not visible externally as it was covered under the surgical drapes (2). The size of the drain chamber was small (50 ml) and inadequate. Once full it could not accommodate the excess blood from the venous ooze. The tight closure of scalp and the full drainage container led the blood to collect extradurally resulting in intracranial hypertension, bradycardia and hyper tension [Cushing’s reflex (3)] followed by severe hypotension and near cardiac arrest. Rebecca Jacob Kamal Kumar Amar Nandhakumar Department of Anaesthesia, Christian Medical College, Vellore, Tamilnadu, India (email: rebeccajacob@hotmail.com)

An intraoral fixation method of endotracheal tube using the surgical suture in pediatric patients

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Endotracheal intubation with Airtraq® optical laryngoscope in the pediatric patients

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