The tracheal accordion and the position of the endotracheal tube.

The purpose of this review is to, first, determine the static factors that affect the length of the human trachea across different populations and, second, to investigate whether or not there are dynamic factors that cause the length of the human trachea to vary within the same individual. We also investigated whether these changes in tracheal length within the same individual are significant enough to increase the risk of endobronchial intubation or accidental extubation. A PubMed/MEDLINE and a Web of Science database English-language literature search was conducted in May 2016 with relevant keywords and MeSH terms when available. We found that gender, extremes of age, patient height, postsurgical changes and co-existing disease are static patient factors that affect the length of the human trachea. Dynamic clinical changes that occur under anaesthesia, including Trendelenburg position, head and neck flexion and extension, paralysis of the diaphragm and pneumoperitoneum, cause the trachea to act as an accordion, decreasing and increasing its length. The length of the human trachea in both awake and anaesthetised and paralysed patients is a critical consideration in preventing both endobronchial intubation and tracheal extubation. It is clear from the literature that tracheal length varies widely across populations and, additionally, with the dynamic clinical changes that occur under anaesthesia, the trachea acts as an accordion decreasing and increasing its length within the same individual. Knowledge of the magnitude of the change in tracheal dimensions in response to these factors is an important clinical consideration.

Management of adult acute epiglottitis by tracheal intubation.

We present a case of adult acute epiglottitis that was successfully managed by endotracheal intubation without the need for subsequent tracheostomy.

The esophageal obturator airway: a clinical comparison to ventilation with a mask and oropharyngeal airway.

We compared controlled ventilation with the esophageal obturator airway to ventilation with a conventional rubber mask and oropharyngeal airway in ten anesthetized patients. Measurements of exhaled tidal volume, mask-to-face fit (leakage of mask), supraglottic obstruction, and the operator's effort were all inferior using the esophageal obturator airway. No consistent peak airway pressure could be obtained with the esophageal obturator airway. Placement of the device was difficult in three of ten patients, and two of ten had inadvertent tracheal intubations. Edentulous patients were difficult to impossible to ventilate using the esophageal obturator airway.

Mechanisms of hypoxemia and hypercapnia in the perioperative period.

There are numerous mechanisms of hypoxemia and hypercapnia during the perioperative period. Mechanisms of hypoxemia include oxygen delivery problems, decreased FAC-CC relationship, hypoventilation, decreased cardiac output, increased oxygen consumption, decreased hypoxic pulmonary vasoconstriction, and increased nonalveolar right-to-left shunting. Mechanisms of hypocapnia include increased carbon dioxide production, increased alveolar dead space, and increased external dead spaces. Pulmonary diseases often involve multiple mechanisms to produce hypoxemia and hypercapnia.

Paraplegia following intracord injection during attempted epidural anesthesia under general anesthesia.

BACKGROUND AND OBJECTIVES: A case of permanent paraplegia is reported following attempted epidural anesthesia for a total knee replacement in a 62-year-old woman with a history of lumbar laminectomy for a prolapsed intervertebral disc. METHODS: Epidural puncture was attempted during general anesthesia and neuromuscular block. RESULTS: After four unsuccessful attempts, an epidural catheter was inserted above the upper end of the laminectomy scar. Several episodes of arterial hypotension occurred intraoperative and postoperative. Operative blood loss was minimal, and no bone glue was used. The patient awoke paraparetic with a sensory level of anesthesia to T5 bilaterally. MRI revealed an air bubble in the cord at T10 and a region of increased T2-weighted signal in the anterior aspect of the spinal cord between T4 and T5, consistent with infarction. CONCLUSION: Standards of management are discussed in relation to this case.

Anesthetic management of a parturient with congenital cavernous transformation of the portal vein and chronic thrombocytopenia.

Cavernous transformation of the portal vein is a rare disorder resulting from extrahepatic portal vein thrombosis and development of collateral venous circulation. We report a case of a pregnant patient with congenital cavernous transformation of the portal vein associated with persistent consumptive coagulopathy and chronic thrombocytopenia. Single dose spinal anesthesia was safely conducted for an uneventful cesarean delivery.

Cesarean section and Ehlers-Danlos syndrome: choice of anesthesia.

Ehlers-Danlos syndrome is a rare genetically transmitted connective tissue disorder, non-specific to pregnancy. Because of multi-organ involvement and varied presentations of this disease, no uniform anesthetic recommendations can be made. We report a case of a parturient with Ehlers-Danlos syndrome who presented in active labor with spontaneous rupture of membranes and footling breech presentation. She received single dose spinal anesthesia for an uneventful emergency cesarean section.

Cesarean section in a parturient with HIV and recent cocaine and alcohol intake: anesthetic implications.

We present a case of a human immunodeficiency virus (HIV) positive, poly-substance abusing parturient who presented for an emergency cesarean section following recent cocaine and alcohol intake. Spinal anesthesia was selected for the abdominal delivery. 4 min after delivery of the fetus, the patient developed hypotension, intermittent runs of ventricular tachycardia, premature ventricular complexes and ST-segment elevation. Induction of general anesthesia, endotracheal intubation, intravenous lidocaine and phenylephrine were required to restore stability. At the end of surgery the patient was stable and was extubated. The ST-segment elevation returned to normal 45 min postoperatively. Her postoperative course was uneventful.

Obstructive sleep apnea in the adult obese patient: implications for airway management.

Obstructive sleep apnea in the adult obese patient may be due, in part, to an increased amount of pharyngeal tissue. Therefore, there is an increased risk of intubation and extubation difficulties and pain management can be expected to be complicated by opioid/sedative-induced pharyngeal collapse.

Quantitative improvement in laryngoscopic view by optimal external laryngeal manipulation.

STUDY OBJECTIVE: To determine the improvement in laryngoscopic view obtained using both the Macintosh and Miller blades by applying optimal external laryngeal manipulation (OELM). DESIGN: Prospective, with each patient serving as his or her own control. SETTING: Inpatient operating rooms of a University Medical Center. PATIENTS: 181 informed and consenting adult nonpregnant patients requiring general anesthesia and tracheal intubation. The only exclusion criteria was the need to apply cricoid pressure to prevent aspiration of gastric contents. INTERVENTIONS: Anesthetized, paralyzed patients underwent laryngoscopy without external laryngeal manipulation and the laryngoscopic view was graded ("A") according to visualized structures [1.0-1.9 = all (1.0) or part of the vocal cords (90% = 1.1 and 10% = 1.9); 2 = just the arytenoids; 3 = just the epiglottis; 4 = just the soft palate]. The larynx was then quickly manipulated by the thumb and index and middle fingers of the laryngoscopist's right hand in both cephalad and posterior directions over the hyoid, thyroid, and cricoid cartilages until it was determined which vector and spot produced the optimal laryngoscopic view ("B"). MEASUREMENTS AND MAIN RESULTS: It was found that in every patient with a "A" greater than 1.0, OELM improved the view; i.e., "B" decreased relative to "A." For both the Macintosh blade patients and Miller blade patients with an "A" equal to 2, "B" decreased by one whole laryngoscopic grade in all patients. For both the Macintosh and Miller blade patients with an "A" equal to 3, "B" decreased by at least one whole laryngoscopic grade in all patients and by two laryngoscopic grades in most patients. No patient had an "A" equal to 4. The distribution of optimal-external-laryngeal-manipulation (OELM) spots for all patients was 1%, 40%, 48%, and 11% for the hyoid, high thyroid, low thyroid, and cricoid cartilages, respectively, and the distribution was not significantly different for either the Macintosh and Miller blade groups or for the "A" and "B" subgroups (i.e., "A" < 1.9, = 2 or = 3). CONCLUSIONS: We conclude that OELM can improve the laryngoscopic view by at least one whole grade, that the best way to determine OELM for an individual patient is on an empirical basis by manipulation of the larynx with the laryngoscopist's right hand, and that OELM should be an instinctive and reflex response to any "A" of 2, 3, or 4.

It is not necessary to remove a jet stylet to determine tracheal tube location.

A jet stylet is a small internal diameter (ID), semirigid hollow catheter that is inserted into an in situ tracheal tube prior to extubation of a patient who may be difficult to reintubate. After the tracheal tube is withdrawn over the jet stylet, the hollow catheter can be used for jet ventilation or as an intratracheal stylet for reintubation with a new tracheal tube. It was previously thought that after the new tracheal tube was inserted over the jet stylet, the stylet would have to be removed to allow connection of the new tube to the breathing circuit and confirmation of intratracheal placement of the tube. We describe a method for preserving the intratracheal location of the jet stylet while confirming intratracheal placement of the new tracheal tube.

The preoperative evaluation form: assessment of quality from one hundred thirty-eight institutions and recommendations for a high-quality form.

STUDY OBJECTIVE: To develop a rating system to evaluate the preoperative evaluation form in three categories: informational content, ease of use, and ease of reading; to analyze forms contributed by the Association of Anesthesia Clinical Directors; to offer an example of a more optimal form; and interest practitioners in evaluating the quality of their evaluation forms. SETTING: University medical center. DESIGN/MEASUREMENTS: The informational content of the forms was graded by a rating system developed to give a score based on the importance of the data to anesthesia management and legal documentation. Based on the amount of informational content, the forms were grouped into categories ranging from severely deficient to excellent. The ease of use and ease of reading were determined by specific criteria. MAIN RESULTS: 138 forms were analyzed. The mean +/- SD information score was 265 +/- 41, with a range of 140 to 333 (maximum score possible = 363). Fifteen percent of the forms were considered severely deficient to substandard whereas 52% were deemed very good to excellent. A large proportion of forms omitted at least one essential information item. Twelve percent and 6% were labeled poor with regard to ease of use and ease of reading, respectively. Academic centers performed significantly better in the content and ease of use of their forms compared to those from private centers. CONCLUSIONS: A good preoperative evaluation form is an important tool in the anesthetic management of a patient and plays a significant role in the medical legal arena. We found that a surprisingly high percentage of forms are missing important information. A form that contains all of the information and also meets our ease of use and reading standards was developed and offered as an example.

Management of the difficult airway.

Respiratory catastrophes are the most common cause of anaesthesia-related brain deaths and death. If an airway is recognised to be difficult, endotracheal tube (ETT) intubation should be performed awake. Awake intubation demands proper preparation of the patient. When the patient is properly prepared any one of a number of ETT intubation techniques can be successful. Once in a great while a surgical airway may be the best first choice. If the patient refuses to be intubated awake, or a difficult airway is not recognised, and anaesthesia is induced, then the airway will ordinarily be first controlled by mask ventilation prior to conventional laryngoscopy. If conventional laryngoscopy should fail, a call for help should be initiated and the airway should be controlled by mask ventilation. If ETT intubation by conventional laryngoscopy is still unsuccessful after a few attempts (perhaps using a different blade or head position) and special alternative techniques fail, the patient should either be awakened, the case done by mask, or a semi-elective surgical airway cricothyroidotomy performed. If at any point mask ventilation becomes impossible and the patient still cannot be intubated, then transtracheal jet ventilation (TTJV) through a percutaneous IV catheter should be instituted. Once life-sustaining gas exchange is again effected by TTJV, then the patient should either be awakened, a semi-elective tracheostomy or cricothyroidotomy performed or the patient intubated with a special ETT intubation technique. An intubated patient with a known difficult airway should be extubated over a jet stylet.

Amphetamine abuse in pregnancy: anesthetic implications.

The prevalence of recreational substance abuse amongst young adults (including women in child-bearing age) has markedly increased over the past two decades and it remains one of the major problems facing our society today--worldwide. Amphetamine is one of the most common substances abused in pregnancy and one of the most potent sympathomimetic amines with respect to stimulatory effects on the central nervous system. The following case report illustrates the problems that may arise during anesthesia in the parturient with recent amphetamine intake.

Once a post-dural puncture headache patient always post-dural puncture headache patient?

It is well known that symptoms of post-dural puncture headache (PDPH) are more likely if there has been a preceding PDPH. We herein present a patient who developed a PDPH following each of two dural punctures separated by 9 years.

AANA Journal Course: update for nurse anesthetists--anesthesia for thoracic surgery: lung separation.

The lungs can be separated by use of either a double-lumen tube (DLT) or a bronchial blocker (BB). Correct positioning of DLTs and BBs is often the most important determinant as to whether thoracic surgery cases (in particular one-lung ventilation cases) and differential lung ventilation in the intensive care unit proceed smoothly. If the method of lung separation is correct, the operative nondependent lung will collapse completely and easily, the surgeon will be able to work efficiently without damaging the operative lung, and the nonoperative lung will be unobstructed and easy to ventilate. For both DLTs and BBs, the key to precise positioning is to visualize, with a fiberoptic bronchoscope, through the tracheal lumen, the occluding endobronchial cuff/balloon just below the tracheal carina.

Interpretation of capnography.

The anesthetist will get the most information out of a capnograph if it is examined systematically. First, the anesthetist must determine whether exhaled CO2 (i.e., a waveform) is present. The differential diagnosis of absent CO2 includes esophageal intubation, accidental tracheal extubation, disconnection of the breathing circuit, complete obstruction of the endotracheal tube or conducting system (kink, inspissated blood or secretions, extremely severe bronchospasm) or of the breathing circuit, apnea, and cardiac arrest. Second, the shape of the waveform must be analyzed systematically by looking at, and in sequence, phase I (inspiratory baseline, which should be zero); phase II (expiratory upstroke, which should be nearly perpendicular to the inspiratory baseline); phase III (expiratory or alveolar plateau, which should be a straight, nearly horizontal, line); and phase IV (inspiratory downstroke, which should be nearly perpendicular to the inspiratory baseline). This discussion will follow this systematic approach but will emphasize diagnosis that can be obtained from the phase III alveolar plateau.

Percutaneous transtracheal jet ventilation: an important airway adjunct.

Situations wherein patients cannot be ventilated or intubated rarely occur. When they do, however, death is imminent unless rapid and accurate actions are taken to restore adequate gas exchange. Under these circumstances, percutaneous transtracheal high-pressure jet ventilation (TTJV) through an intravenous catheter is life saving. The authors report two recent cases where TTJV was employed to regain control over obstructed upper airways. Discussion of the cases and the therapeutic modality follows. The summary includes a call for the immediate availability of TTJV at all anesthetizing locations.