Arjang Khorasani

Dantrolene Treatment for Abrupt Intrathecal Baclofen Withdrawal

I ntrathecal administration of baclofen produces cerebrospinal fluid (CSF) concentrations 100 times greater than those occurring with oral administration and has been used for treatment of spasticity in patients with spinal cord injury who are refractory to, or cannot tolerate, oral baclofen (1,2). Since intrathecal administration of baclofen achieves high concentrations in the spinal cord with small doses, the incidence of central nervous system adverse effects such as sedation, drowsiness, vertigo, dizziness, weakness, fatigue, and confusion are significantly reduced (1). Abrupt withdrawal of oral baclofen after long-term use may produce hallucinations, confusion, manicpsychotic episodes, seizures, autonomic dysreflexia, hyperthermia, and rebound severe spasticity (3,4X Administration of oral baclofen may decrease the spasticity and the hyperthermia associated with abrupt oral baclofen withdrawal (4). We present a case of severe hyperthermia and spasticity due to abrupt withdrawal of baclofen which was unresponsive to high-dose oral baclofen, but was responsive to dantrolene.

Post-dural puncture headache.

Since August Bier reported the first case in 1898, post-dural puncture headache (PDPH) has been a problem for patients following dural puncture. Clinical and laboratory research over the last 30 years has shown that use of smaller-gauge needles, particularly of the pencil-point design, are associated with a lower risk of PDPH than traditional cutting point needle tips (Quincke-point needle). A careful history can rule out other causes of headache. A postural component of headache is the sine qua non of PDPH. In high-risk patients < 50 years, post-partum, in the event a large-gauge needle puncture is initiated, an epidural blood patch should be performed within 24–48 hours of dural puncture. The optimum volume of blood has been shown to be 12–20 mL for adult patients. Complications caused by autologous epidural blood patching (AEBP) are rare.

Canister tip orientation and residual volume have significant impact on the dose of benzocaine delivered by hurricaine® spray

Delivered quantities of 20% benzocaine spray (Hurricaine; Beutlich L.P. Pharmaceuticals, Waukegan, IL) are estimated by counting the number of sprays or the spraying time. Because Hurricaine spray supplies a continuous (albeit nonmetered) stream of benzocaine, neither method addresses delivered dose. We hypothesized that dose per time is a function of canister content and orientation. Thirty full canisters of Hurricaine were placed into three equal orientations (upright, inverted, or horizontal). Extrapolating from a full canister, four different estimates of benzocaine residual volume were determined before spraying out the contents (80%, 60%, 40%, and 20% full). Each canister was then sprayed for 10-s intervals, and the quantity delivered was calculated and compared statistically. Upright canisters 100% full emitted more benzocaine than canisters with residual volume 20% full (190 +/- 10 vs 172 +/- 10 mg/s). Inverted canisters emitted significantly less benzocaine from 100% full to residual volume 20% full (188 +/- 14 vs 70 +/- 10 mg/s). Oriented horizontally, two full canisters emitted <76 mg/s benzocaine, contrasted with the remaining eight in that group (186 +/- 20 mg/s). We conclude that the benzocaine (Hurricaine) sprayed in milligrams per second depends on canister content and orientation. When residual volumes diminish, there is a reduction in spraying volume per time. This diminution occurs progressively from larger to smaller residual volumes with canisters oriented horizontally, inverted, or upright. Arbitrary documentation of spraying time bears no relationship to dose delivered. Perhaps affixing an atomization device to a graduated syringe filled with benzocaine will help increase accuracy and precision in dosing.

Gastric tubes and airway management in patients at risk of aspiration: history, current concepts, and proposal of an algorithm.

Rapid sequence induction and intubation (RSII) and awake tracheal intubation are commonly used anesthetic techniques in patients at risk of pulmonary aspiration of gastric or esophageal contents. Some of these patients may have a gastric tube (GT) placed preoperatively. Currently, there are no guidelines regarding which patient should have a GT placed before anesthetic induction. Furthermore, clinicians are not in agreement as to whether to keep a GT in situ, or to partially or completely withdraw it before anesthetic induction. In this review we provide a historical perspective of the use of GTs during anesthetic induction in patients at risk of pulmonary aspiration. Before the introduction of cricoid pressure (CP) in 1961, various techniques were used including RSII combined with a head-up tilt. Sellick initially recommended the withdrawal of the GT before anesthetic induction. He hypothesized that a GT increases the risk of regurgitation and interferes with the compression of the upper esophagus during CP. He later modified his view and emphasized the safety of CP in the presence of a GT. Despite subsequent studies supporting the effectiveness of CP in occluding the esophagus around a GT, Sellick’s early view has been perpetuated by investigators who recommend partial or complete withdrawal of the GT. On the basis of available information, we have formulated an algorithm for airway management in patients at risk of aspiration of gastric or esophageal contents. The approach in an individual patient depends on: the procedure; type and severity of the underlying pathology; state of consciousness; likelihood of difficult airway; whether or not the GT is in place; contraindications to the use of RSII or CP. The algorithm calls for the preanesthetic use of a large-bore GT to remove undigested food particles and awake intubation in patients with achalasia, and emptying the pouch by external pressure and avoidance of a GT in patients with Zenker diverticulum. It also stipulates that in patients with gastric distension without predictable airway difficulties, a clinical and imaging assessment will determine the need for a GT and in severe cases an attempt to insert a GT should be made. In the latter cases, the success of placement will indicate whether to use RSII or awake intubation. The GT should not be withdrawn and should be connected to suction during induction. Airway management and the use of GTs in the surgical correction of certain gastrointestinal anomalies in infants and children are discussed.

Cricoid Pressure Controversies: Narrative Review

Since cricoid pressure was introduced into clinical practice, controversial issues have arisen, including necessity, effectiveness in preventing aspiration, quantifying the cricoid force, and its reliability in certain clinical entities and in the presence of gastric tubes. Cricoid pressure–associated complications have also been alleged, such as airway obstruction leading to interference with manual ventilation, laryngeal visualization, tracheal intubation, placement of supraglottic devices, and relaxation of the lower esophageal sphincter. This review synthesizes available information to identify, address, and attempt to resolve the controversies related to cricoid pressure. The effective use of cricoid pressure requires that the applied force is sufficient to occlude the esophageal entrance while avoiding airway-related complications. Most of these complications are caused by excessive or inadequate force or by misapplication of cricoid pressure. Because a simple-to-use and reliable cricoid pressure device is not commercially available, regular training of personnel, using technology-enhanced cricoid pressure simulation, is required. The current status of cricoid pressure and objectives for future cricoid pressure–related research are also discussed.

Inadvertent misconnection of the scavenger hose: A cause for increased pressure in the breathing circuit.

74:1166–70 5. Gammie JS, Zenati M, Kormos RL, Hatter BG, Wei LM, Pellegrini RV, Griffith BP, Dyke CM: Abciximab and excessive bleeding in patients undergoing emergency cardiac operations. Ann Thor Surg 1998; 65:465–9 6. Despotis GJ, Levine V, Filos KS, Joiner-Maier D, Joist, JH: Hemofiltration during cardiopulmonary bypass: the effect of anti-Xa and anti-IIa heparin activity. Anesth Analg 1997; 84:479–83

Ultrasound evaluation of cricoid pressure vs. ‘paralaryngeal pressure’

observational studies and metaanalyses. Whilst much of the initial data related to the adult sizes of the i-gel, the body of evidence for the paediatric sizes is now also significant [3–6], and in our view confirms that providing the device is used in accordance with the instructions for use [2], it performs well, has low rates of complications and may offer advantages over a number of other supraglottic airways, including lower postoperative sore throat, higher seal pressures and easier and more rapid insertion. We very closely monitor all feedback on the i-gel to ensure it continues to perform appropriately and the level and nature of complaints or problems are not in excess of the normal range and type associated with the use of other supraglottic airways currently available in the market and regarded as safe devices. This includes robust formal product complaint and post-marketing surveillance systems and procedures.

Post-dural puncture headache [Retraction]

[This retracts the article on p. 45 in vol. 5, PMID: 22287846.].

Succinylcholine Cannot Relieve an Airway Obstruction Caused by Pharyngeal and Laryngeal Edema

In their case report, Ibarra et al. (1) describe a patient with pharyngeal and laryngeal edema that they attribute to traumatic asphyxia. Although we agree that traumatic asphyxia may change the structural contour of upper airway, we disagree with the authors on three issues. First, the authors elected to induce their patient with class IV Mallampati airway using succinylcholine and thiopental when airway obstruction developed after failed attempts at direct awake laryngoscopy. Although the authors report resolution of airway obstruction and achievement of good ventilation after the administration of IV anesthesia, yet this technique is not at all the best approach for securing an obstructed airway. Succinylcholine cannot relieve an airway obstruction if, indeed, it was caused by pharyngeal and laryngeal edema. If the ventilation and visualization of the larynx were satisfactory after the induction of anesthesia, why did the tracheal intubation attempt fail and immediate cricothyroidotomy become necessary? Second, the report of arterial blood gas result is incorrect. The Henderson-Hasselbalch equation for bicarbonate buffer system may be used to exclude the possibility of an incorrect blood gas report. According to this equation, it is impossible to have a pH, of 7.24, Pace, of 24 mm Hg, and HCO,of 15.8 mEq/L. For the pH, to be 7.24, either the bicarbonate should be lower (9.93 mEq/L), the Pace, should be higher (38.16 mm Hg), or both. Third, the authors fail to explain their rationale for the transfusion of 8 U of packed red blood cells, 8 U of fresh-frozen plasma, 5 U of platelets, and 2 L of lactated Ringer’s solution. A decreasing hemoglobin level (from 10.5 to 8 g/dL) and hypotension do not constitute adequate indication for this massive transfusion of blood products.