To the Editor

In a Letter to the Editor appearing in the Fall 1990 APSF Newsletter (1), Drs. Kataria and Nicodemus offer readers a response algorithm for dealing with the emergency of difficulty in ventilating a patient via endotracheal tube (EM following apparent intubation of the trachea. They are to be commended for their effort to formulate a simple, systematic approach to a potential catastrophe. However, conspicuously (and inexplicably) absent from their protocol is a branch point which stresses the urgent need to ensure adequate oxygenation and ventilation of the patient by some means other than the recently placed ETT.

The main branch of the algorithm begins with the determination that the difficulty in ventilating via the M is due to a problem on the patient side of the breathing system, and proceeds through a series of steps which include reauscultatation, repeat laryngoscopy, passage of a suction catheter via ETT, and even chest x-ray and fiberoptic bronchoscopy to confirm proper placement of the ETT in the trachea. If followed to its conclusion in the setting of difficulty or inability to ventilate via ETT, such a protocol would virtually guarantee significant hypoxemia in an anesthetized, apneic patient, even if preoxygenation had been employed.

As competent and caring practitioners, most anesthesiologists and anesthetists might react to this criticism by exclaiming “Well, of course, we wouldn’t take this sequence literally; we would ensure that the patient is oxygenated!” as, I am sure, would the authors of the protocol. The very nature of our training and clinical thinking rests on the foundation of providing for adequate oxygen delivery to the vital organs of any patient under our care. However, performing this vital task in the circumstance whereby an ETT is malfunctioning necessarily requires removal of the ETT and resumption of controlled ventilation via facemask, assuming the latter had preceded laryngoscopy and had not been diffucult. This, of course, violates the prescribed sequence of steps in the algorithm, thus negating its utility and validity.

A clinical response algorithm has been defined as “a logical sequence of [steps] to be [followed] in response to a specific condition [as a] guide… in performing maneuvers of maximal diagnostic merit in the least amount of time” (2) Such stereotyped responses to clinical problems have occasionally been criticized because of their apparent promotion of an unthinking “cookbook” approach to problem-solving. (3, 4)

Although, by definition, an algorithm indeed precludes a knowledgeable interpretation of data and reliance on considered judgement, it is intended to service as a surrogate for the latter. As such, it is valid only in a clinical circumstance exhibiting such a degree of emergency that, with time at a premium and stress at a peak, judgment might reasonably be expected to be clouded and responses should occur by rote. A valid algorithm must therefore dearly prescribe the proper application of fundamental principles without containing any unspecified presuppositions. If it does not, then it is, at best, redundant and, at worst, dangerous.

The protocol suggested by Drs. Kataria and Nicademus for dealing with unanticipated difficulty in ventilating a patient following endotracheal intubation, an emergency which they themselves describe as one which “can lead to patient mortality or morbidity if not handled in a timely and intelligent manner [emphasis mine],” (1) falls short by omitting an early step for otherwise ensuring adequacy of oxygenation and ventilation. Assuming the patient had not been difficult to ventilate by mask prior laryngoscopy, such a step would likely be to remove the ETT and resume ventilation with 100% oxygen via facemask. In the much less likely but far more dangerous situation in which neither ventilation by M nor mask is possible, detailed response guidelines have been offered elsewhere. (5)

Robert E Atkins, M.D.

Abington (PA) Memorial Hospital; Assistant Professor of Anesthesia

Temple University School of Medicine

References

1. Kataria B, Nicodemus R. Protocol suggested for ventilation problem following intubation (letter). APSF Newsletter 1990; Vol. 5, No. 3, p. 30.
2. Raphael DT, Weller RS, Doran DJ. A response algorithm for the low-pressure alarm condition. Anesth Analg 1988; 67:876-83.
3. Standards and guidelines for cardiopulmonary resuscitation (CPR) and emergency cardiac care (ECC). JAMA 1986; 255:2905-2932.
4. Narins RG, Cohn JJ. Bicarbonate therapy for organic acidosis: the case for its continued us (editorial). Ann Int Med 1987; 106: 615-8.
5. Benumof JL, Scheller, MS. The importance of transtracheal jet ventilation in the management of the difficult airway. Anesthesiology 1989; 71:769-78.