A stab in the dark?
Tension pneumothoraces (TP) are life-threatening injuries that may be treated by needle thoracocentesis (NT). The technique is not without complications, hence this research investigating the accuracy of NT placement by prehospital clinicians. This review, based in the United States, assessed the accuracy of insertion of catheters including the location of the insertion site, accuracy of landmark identification, and complication rates of NT in trauma patients. The locations of insertion were measured and documented using computerised tomography (CT) scans.
The research was a single-centre study of 84 patients that were transported to a level-2 trauma centre over 2 years, all of whom appeared to have TP. The symptoms were defined by the local medical agency and each patient had to have survived their initial emergency department assessment/treatment and made it through the CT scan alive as per the normal trauma protocol. The study protocol required that the inserted catheters remained in place and were not dislodged. Each patient's insertion location was naturally described in the CT report and noted as inside the pleural cavity versus insertion outside the pleural cavity. The study included other data points such as gender, mechanism of injury, chest tube placement and body mass index (BMI).
The results identified that there was improper placement in 73% of patients with there being higher rates of misplacement at the second intercostal space versus the forth/fifth intercostal space midaxillary line (ICS MAL). Misplacements included the catheter being inserted in organ or soft tissue. The clinicians favoured the second intercostal space (ICS) in the midclavicular line, which meant that the catheters fell short of the length needed to reach the pleural cavity in patients with a thicker chest wall.
Overall, this literature highlights the need for further training and review of locations given the high failure rate and significant consequence if performed incorrectly.
Rotate to ventilate?
Mask ventilation is an essential skill for apnoeic subjects during resuscitation; however, upper airway obstruction occurs frequently and may cause difficult, and sometimes impossible, mask ventilation. Head and body positions such as head-tilt, chin-lift, are known to influence upper airway patency. However, the effect of axial head rotation on airway patency has not been evaluated systematically.
The aim of this randomised crossover study was to establish whether head rotation improves the efficiency of mask ventilation of anaesthetised apnoeic adults.
Patients were randomised to one of two groups. In the first group (Group A), the mask ventilation was performed with a neutral head position for 1 minute (total: 10 breaths), followed by an axial head position rotated 450 to the right for 1 minute (Step 2) and, finally, the head was returned to the neutral position for another 1 minute. In the second group (Group B), all the ventilator settings were identical to those of Group A, but the sequence of head positioning was rotated, then neutral, then rotated. Head rotation was estimated with the aid of a protractor.
Data from 38 patients ranging from 18–75 years and with a BMI of between 18.5 and 35 were analysed. The main outcome measure was expiratory tidal volume, measured with a respiratory inductive plethysmograph.
Results showed that the mean expiratory tidal volume was significantly higher in the rotated head position than in the neutral position (612.6 vs 544.0 ml: difference [95% confidence interval (CI)], 68.6 [46.8 to 90.4] ml, P<0.0001). The authors concluded that head rotation of 45° in anaesthetised apnoeic adults significantly increases the efficiency of mask ventilation compared with the neutral head position. All patients experienced benefit from the rotation. However, those with airway obstruction, younger age and Mallampati classification I benefitted the most. This is perhaps worth considering when paramedics encounter airway obstruction in the field.