Final answer:
The esophageal intubation is no longer recommended for securing the airway, while external laryngeal manipulation is still acceptable to visualize the larynx during proper endotracheal intubation.
Step-by-step explanation:
The maneuver that is no longer recommended for intubation is the intubation of the esophagus. While external laryngeal manipulation can be employed to improve visualization during intubation, inserting an endotracheal tube into the esophagus—an erroneous practice formerly known as esophageal intubation—is now considered an incorrect technique. Esophageal intubation was used historically when other methods of securing the airway failed, but it's no longer recommended due to the high risk of complications like inadequate ventilation and subsequent hypoxia.
Intubation is a medical procedure wherein a tube is inserted into the trachea through the mouth or nose to maintain an open airway, administer drugs, or provide mechanical ventilation. The Heimlich maneuver, mentioned in the reference information, is a separate emergency procedure used to dislodge objects from the respiratory tract to prevent choking and asphyxiation.