Airway injury from the presence of endotracheal tubes and the association with subglottic secretion drainage: a prospective observational study

PURPOSE

Laryngeal and tracheal injuries are known complications of endotracheal intubation. Endotracheal tubes (ETTs) with subglottic suction devices (SSDs) are commonly used in the critical care setting. There is concern that herniation of tissue into the suction port of these devices may lead to tracheal injury resulting in serious clinical consequences such as tracheal stenosis. We aimed to describe the type and location of tracheal injuries seen in intubated critically ill patients and assess injuries at the suction port as well as in-hospital complications associated with those injuries.

METHODS

We conducted a prospective observational study of 57 critically ill patients admitted to a level 3 intensive care unit who were endotracheally intubated and underwent percutaneous tracheostomy. Investigators performed bronchoscopy and photographic evaluation of the airway during the percutaneous tracheostomy procedure to evaluate tracheal and laryngeal injury.

RESULTS

Forty-one (72%) patients intubated with ETT with SSD and sixteen (28%) patients with standard ETT were included in the study. Forty-seven (83%) patients had a documented airway injury ranging from hyperemia to deep ulceration of the mucosa. A common tracheal injury was at the site of the tracheal cuff. Injury at the site of the subglottic suction device was seen in 5/41 (12%) patients. There were no in-hospital complications.

CONCLUSIONS

Airway injury was common in critically ill patients following endotracheal intubation, and tracheal injury commonly occurred at the site of the endotracheal cuff. Injury occurred at the site of the subglottic suction port in some patients although the clinical consequences of these injuries remain unclear.

Measuring physician cognitive load: validity evidence for a physiologic and a psychometric tool

In general, researchers attempt to quantify cognitive load using physiologic and psychometric measures. Although the construct measured by both of these metrics is thought to represent overall cognitive load, there is a paucity of studies that compares these techniques to one another. The authors compared data obtained from one physiologic tool (pupillometry) to one psychometric tool (Paas scale) to explore whether they actually measured the construct of cognitive load as purported. Thirty-two participants with a range of resuscitation medicine experience and expertise completed resuscitation-medicine based multiple-choice-questions as well as arithmetic questions. Cognitive load, as measured by both tools, was found to be higher for the more difficult questions as well as for questions that were answered incorrectly (p < 0.001). The group with the least medical experience had higher cognitive load than both the intermediate and experienced groups when answering domain-specific questions (p = 0.023 and p = 0.003 respectively for the physiologic tool; p = 0.006 and p < 0.001 respectively for the psychometric tool). There was a strong positive correlation (Spearman's ρ = 0.827, p < 0.001 for arithmetic questions; Spearman's ρ = 0.606, p < 0.001 for medical questions) between the two cognitive load measurement tools. These findings support the validity argument that both physiologic and psychometric metrics measure the construct of cognitive load.

rFVIIa in trauma: a review and opinion-based guidelines

Recombinant activated factor seven (rFVIIa) is a novel and emerging therapy for the acquired coagulopathy associated with massive bleeding and hemorrhagic shock. The intent of this paper is to review the mechanism of action of rFVIIa, to discuss the current state of evidence regarding the safety and efficacy of rFVIIa, and to offer guidance regarding its use in severely traumatized patients. No study has demonstrated a survival benefit in humans. rFVIIa, is safe to use in the setting of severe trauma associated with ongoing bleeding and acquired coagulopathy. Doses of 80—200 μg/kg may be used after correction of thrombocytopenia and acidosis. Hypothermia should be corrected in any traumatized patient, but should not be a barrier to its administration. Definitive evidence supporting the use of rFVIIa is lacking, but ongoing studies will delineate survival benefits, dosing regimens, and adverse events associated with its use.

Lateral canthotomy and cantholysis: a simple, vision-saving procedure

Lateral canthotomy and cantholysis is a simple procedure that can be performed by emergency physicians. It has the potential to save vision, particularly in cases of blunt ocular trauma. The case of a 37-year-old man with blunt ocular trauma, a retrobulbar hemorrhage and rapidly increasing orbital pressure requiring an urgent lateral canthotomy and cantholysis is presented. Pathophysiology, indications, contraindications, procedure and follow-up care are described.

Herpes Simplex Virus Hepatitis in an Immunocompetent Adult: A Fatal Outcome due to Liver Failure

Objective. To present a case of a healthy 41-year-old female who developed fulminant hepatic failure leading to death. The cause of hepatic failure identified on postmortem exam was herpes simplex virus hepatitis. Design. Observation of a single patient. Setting. Intensive care unit of a tertiary care university teaching hospital in Canada. Patient. 41-year-old previously healthy female presenting with a nonspecific viral illness and systemic inflammatory response syndrome. Intervention. The patient was treated with intravenous fluids and broad-spectrum antibiotics. On the second day of admission, she was found to have elevated transaminases, and, over 48 hours, she progressed to fulminant liver failure with disseminated intravascular coagulopathy, refractory lactic acidosis, and shock. She progressed to respiratory failure requiring intubation and mechanical ventilation. She was started on N-acetylcysteine, a bicarbonate infusion, hemodialysis, and multiple vasopressors and inotropes. Measurements and Main Results. Despite treatment, the patient died roughly 70 hours after her initial presentation to hospital. Her postmortem liver biopsy revealed herpes simplex virus hepatitis as her cause of death. Conclusions. Herpes simplex virus must be considered in all patients presenting with liver failure of unknown cause. If suspected, prompt treatment with acyclovir should be initiated.

Colorimetric carbon dioxide detector to determine accidental tracheal feeding tube placement

PURPOSE

To determine the accuracy of colorimetric CO2 detection compared to the reference standard two-step radiological confirmation of feeding tube position.

METHODS

A prospective study was conducted with patients presenting to a 21-bed medical-surgical intensive care unit. An adapter was developed using an endotracheal tube adapter to connect a colorimetric CO2 detector to a feeding tube in an airtight manner. In part I of the study a feeding tube connected to the colorimeter was inserted into the endotracheal tubes of ten ventilated patients to test the device's ability to detect tracheal placement. In part II patients undergoing feeding tube insertion had tube position confirmed with the colorimeter as well as the reference standard two-step x-ray.

RESULTS

In phase I the colorimeter correctly identified tracheal placement in all ten patients. In phase II 93/100 procedures ultimately were eligible; the colorimeter had a sensitivity of 0.88 (95% confidence interval: 0.65-1.00) and specificity of 0.99 (0.97-1.00). The device missed one of the eight tracheal placements. Agreement between the colorimeter and two-step x-ray interpretations was excellent (Kappa 0.86; standard error 0.10).

CONCLUSION

We describe a novel, convenient method to confirm esophageal feeding tube placement. The device is easily assembled and inexpensive, but should not be reused. Colorimetric determination of tracheal feeding tube placement with this device has excellent agreement with the reference standard two-step radiological technique.

Justification of pulse oximeter costs for paramedic prehospital providers

OBJECTIVE

To assess the potential cost savings of decreasing prehospital oxygen utilization by using pulse oximetry to identify those patients who do not require supplemental oxygen.

METHODS

A prospective, controlled trial was performed comparing rates of oxygen utilization by paramedics with and without access to pulse oximetry. Consecutive patient encounters over a ten-week period were randomized by day of presentation. Pulse oximeters were made available on alternate days. On those days, patients whose oxygen saturations were less than 95% were treated with supplemental oxygen.

RESULTS

The use of pulse oximeters incurred a saving of 0.14 "D"-size oxygen cylinders per call. For the authors' service, this translates to a potential saving of $2,324 (C)/vehicle/year.

CONCLUSION

For regions with patient demographics similar to the authors', the initial cost of providing paramedics with pulse oximeters may be offset by savings in oxygen consumption. A formula is provided to allow individual ambulance services to calculate the potential savings for their service.

Overlap and the errors of plaque counting. I. The overlap biases of observed counts and their correction

The number of plaque-forming units is underestimated if plaques overlap. A simple model was developed to account for this bias, and tested by an extensive experimental analysis. It is shown that models of this type are inadequate, but can be modified to give objective methods for setting limits to the acceptable counting range, and for correcting the overlap bias of observed counts which fall within this range.

Where overlapping of plaques is a significant source of error, these methods will improve the efficiency of plaque assays and will render the statistical analysis of counting data more reliable.

Overlap and the errors of plaque counting. II.the bias of the variance and the concealment of errors

The overlapping of plaques compresses their distributions and reduces observed variances. For a given distribution the reduction of the variance is substantially larger than that of the mean. To derive the error of a plaque assay from the assumption that the variance equals the mean may therefore lead to serious over-estimation of the precision of the assay.

Procedures for estimating the true error of plaque assays are developed, and their use is illustrated on experimental material.