Tracheobronchomalacia and Excessive Dynamic Airway Collapse.

Tracheobronchomalacia (TBM) and excessive dynamic airway collapse (EDAC) are more frequently being recognized as the etiology of multiple types of respiratory complaints from chronic cough to exertional syncope to recurrent infections. Identification of these conditions requires a high suspicion, as well as a thorough history and physical examination. Dynamic computed tomography imaging and bronchoscopic evaluation are integral in achieving an accurate diagnosis. Once recognized, treatment ranges from addressing underlying contributing conditions to surgical stabilization of the airway. Referral to an institution familiar with the evaluation and treatment of TBM/EDAC is essential for the appropriate management of these conditions.

New device for nonvolitional evaluation of quadriceps force in ventilated patients.

INTRODUCTION: In mechanically ventilated patients, nonvolitional assessment of quadriceps weakness using femoral-nerve stimulation (twitch force) while the leg rests on a right-angle trapezoid or dangles from the bed edge is impractical. Accordingly, we developed a knee-support apparatus for use in ventilated patients. METHODS: Ninety subjects (12 ventilated patients, 28 ambulatory patients, and 50 healthy subjects) were enrolled. Twitches with leg-dangling, trapezoid, and knee-support setups were compared. RESULTS: Knee-support twitches were similar to trapezoid twitches but smaller than leg-dangling twitches (P < 0.0001). Inter- and intraoperator agreement was high for knee-support twitches at 1 week and 1 month. In ventilated patients, knee-support twitches were smaller than in healthy subjects and ambulatory patients (P < 0.004). DISCUSSION: The new knee-support apparatus allows accurate recording of quadriceps twitches. The ease of use in ventilated patients and excellent inter- and intraoperator agreement suggest that this technique is suitable for cross-sectional and longitudinal studies in critically ill patients. Muscle Nerve 57: 784-791, 2018.

Validity and reliability of rectus femoris ultrasound measurements: Comparison of curved-array and linear-array transducers.

Muscle-mass loss augers increased morbidity and mortality in critically ill patients. Muscle-mass loss can be assessed by wide linear-array ultrasound transducers connected to cumbersome, expensive console units. Whether cheaper, hand-carried units equipped with curved-array transducers can be used as alternatives is unknown. Accordingly, our primary aim was to investigate in 15 nondisabled subjects the validity of measurements of rectus femoris cross-sectional area by using a curved-array transducer against a linear-array transducer-the reference-standard technique. In these subjects, we also determined the reliability of measurements obtained by a novice operator versus measurements obtained by an experienced operator. Lastly, the relationship between quadriceps strength and rectus area recorded by two experienced operators with a curved-array transducer was assessed in 17 patients with chronic obstructive pulmonary disease (COPD). In nondisabled subjects, the rectus cross-sectional area measured with the curved-array transducer by the novice and experienced operators was valid (intraclass correlation coefficient [ICC]: 0.98, typical percentage error [%TE]: 3.7%) and reliable (ICC: 0.79, %TE: 9.7%). In the subjects with COPD, both reliability (ICC: 0.99) and repeatability (%TE: 7.6% and 9.8%) were high. Rectus area was related to quadriceps strength in COPD for both experienced operators (coefficient of determination: 0.67 and 0.70). In conclusion, measurements of rectus femoris cross-sectional area recorded with a curved-array transducer connected to a hand-carried unit are valid, reliable, and reproducible, leading us to contend that this technique is suitable for cross-sectional and longitudinal studies.

Life-threatening hypokalemia following rapid correction of respiratory acidosis.

A 56-year-old woman with a history of paraplegia and chronic pain due to neuromyelitis optica (Devic's syndrome) was admitted to a spinal cord injury unit for management of a sacral decubitus ulcer. During the hospitalization, she required emergency transfer to the intensive care unit (ICU) because of progressive deterioration of respiratory muscle function, severe respiratory acidosis, obtundation and hypotension. Upon transfer to the ICU, arterial blood gas revealed severe acute-on-chronic respiratory acidosis (pH 7.00, PCO2 120 mm Hg, PO2 211 mm Hg). The patient was immediately intubated and mechanically ventilated. Intravenous fluid boluses of normal saline (10.5 L in about 24 h) and vasopressors were started with rapid correction of hypotension. In addition, she was given hydrocortisone. Within 40 min of initiation of mechanical ventilation, there was improvement in acute respiratory acidosis. Sixteen hours later, however, the patient developed life-threatening hypokalemia (K(+) of 2.1 mEq/L) and hypomagnesemia (Mg of 1.4 mg/dL). Despite aggressive potassium supplementation, hypokalemia continued to worsen over the next several hours (K(+) of 1.7 mEq/L). Urine studies revealed renal potassium wasting. We reason that the recalcitrant life-threatening hypokalemia was caused by several mechanisms including total body potassium depletion (chronic respiratory acidosis), a shift of potassium from the extracellular to intracellular space (rapid correction of respiratory acidosis with mechanical ventilation), increased sodium delivery to the distal nephron (normal saline resuscitation), hyperaldosteronism (secondary to hypotension plus administration of hydrocortisone) and hypomagnesemia. We conclude that rapid correction of respiratory acidosis, especially in the setting of hypotension, can lead to life-threatening hypokalemia. Serum potassium levels must be monitored closely in these patients, as failure to do so can lead to potentially lethal consequences.

A complicated hospitalization following dilute ammonium chloride ingestion.

INTRODUCTION: Unintentional ingestions of dilute (<7.5%) cleaning solutions containing ammonium chloride typically do not cause serious harm. We present a case of an intentional ingestion of a dilute ammonium chloride solution resulting in significant morbidity. CASE REPORT: A 60-year-old woman with bipolar disorder presented one hour after an intentional ingestion of approximately 15 fluid ounces (500 mL) of an algae and odor humidifier treatment containing a total of 2.25% ethyl ammonium chloride. Initial complaints included nausea with a single episode of nonbilious, nonbloody emesis, mild shortness of breath, and chest and epigastric pain. Physical exam was remarkable for bilateral wheezing and epigastric tenderness. An emergent endoscopy demonstrated a Grade 2b caustic injury in the esophagus and a Grade 3b injury in the stomach. Due to persistent cough, copious oral secretions, and worsening hoarseness, the patient was intubated and admitted to the ICU. Her course was complicated by mild hypotension, nonanion gap metabolic acidosis, and oliguria treated successfully with intravenous (IV) fluids. She also developed bilateral pneumonias later in the hospital course. Bedside bronchoscopy showed laryngeal edema and mucosal injury to the segmental level. The patient underwent tracheostomy on hospital day 6. An upper GI swallow study revealed poor esophageal motility in the mid- to lower third of the esophagus. The patient gradually tolerated oral fluids and on hospital day 20 had her tracheostomy tube removed. The patient was subsequently transferred to the psychiatric ward on hospital day 22. CONCLUSION: Intentional ingestions of dilute ammonium chloride solutions can cause serious injury to the gastrointestinal tract and pulmonary systems, which can result in a complicated and prolonged hospitalization.

Topical pyrethrin toxicity leading to acute-onset stuttering in a toddler.

Pyrethrin compounds can cause neurotoxicity when used in an excessive dose. A case of stuttering and general clumsiness in a toddler associated with topical pyrethrin use is described.