Criteria abstracted from The Users' Guide to Medical Literature, from the Health Information Research Unit and Clinical Epidemiology and Biostatistics, McMaster University

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Article Reviewed:

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Effect of Out-of-Hospital Pediatric Endotracheal Intubation on Survival and Neurological Outcome: A Controlled Clinical Trial

Gausche M, Lewis RJ, Stratton SJ, et al.

JAMA 2000;283:783-790. [abstract] [full-text for a limited time]

Reviewed by Jennifer Gregory, MD and Ken Tegtmeyer, MD, University of Minnesota

Review posted September 10, 2000

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I. What is being studied?:

The study objective:

To compare survival and neurologic outcomes of pediatric patients treated in the pre-hospital setting with bag-valve-mask (BVM) ventilation to patients treated with BVM followed by endotracheal intubation (ETI)

The study design:

A quasirandomized controlled clinical trial which took place between 1994-1997. It was an extensive undertaking which involved training almost 2600 licensed paramedics at 56 paramedic provider agencies.

The patients included:

The study involved 830 patients under the age of twelve estimated to weigh less than 40 kilograms who required airway management by emergency medical services.

The patients excluded:

All patients over the age of 13 or greater than 40 kilograms as well as patients not requiring airway management were excluded.

Operator inclusion/exclusion:

Since this study is dependent on the performance of the paramedics. It is important to note that all of the eligible paramedics in the area under study were included in the trial. One must then assume that the occasion of a critical illness enrolling a patient into the study is random to allow reasonable distribution amongst the group of paramedics.

The interventions compared:

BVM with or without ETI (410 patients in the BVM group and 420 patients in the BVM with ETI group)

The outcomes evaluated:

Two major outcomes were evaluated:

1. survival to hospital discharge
2. neurologic outcome - based on a modified version of the Pediatric Cerebral Performance Category Scale (1).

II. Are the results of the study valid?

Primary questions:

1. Was the assignment of patients to treatments randomized?

No. The assignment was based on calendar days. On odd days paramedics were assigned to resuscitate patients with BVM, even days to BVM followed by ETI.

2. Were all patients who entered the trial properly accounted for and attributed at its conclusion?

Was followup complete?

Almost. Ten patients were excluded from extensive analysis because of incomplete records. These patients were evenly distributed between the groups (6 for BVM, 4 for ETI).

Were patients analyzed in the groups to which they were randomized?

Yes. Patients were analyzed in an intent to treat fashion, regardless of the actual therapy they received. Secondary analysis was performed afterwards based on treatment received.

Secondary questions:

3. Were patients, health workers, and study personnel "blind" to treatment?

No, as this was not feasible.

4. Were the groups similar at the start of the trial?

Yes. The only statistically significant difference was in the number of patients with a Final Diagnosis of SIDS being higher in the ETI group.

5. Aside from the experimental intervention, were the groups treated equally?

As far as we can tell, yes. All paramedics went through extensive training prior to involvement in the study. Aside from airway management which varied based on protocol, the patients were treated within standard resuscitation guidelines. It is not clear how evenly distributed the paramedics were amongst the two groups. Since varying skill levels amongst the paramedics could influence the outcomes, this could be important. There is no comment on the number of patients enrolled per paramedic group. Given the large number of paramedics, compared to the number of patients one might be able to assume that the paramedics were evenly distributed.

III. What were the results?

1. How large was the treatment effect?

In analyzing the data of 820 patients treated with BVM or BVM with ETI, the authors found no significant difference in survival or neurologic outcome between the two groups.

	BVM	ETI	Odds Ratio, 95% CI
Survival	123/404 (30%)	110/416 (26%)	0.82, 0.61-1.11
‘Good’ Neurological Outcome	92/404 (23%)	85/416 (20%)	0.87, 0.62-1.22

Good Neurological Outcome was defined as normal, mild deficit or no change from baseline.

2. How precise was the estimate of the treatment effect?

The relative risk suggest that for survival the range was from at 39% decreased risk of dying with BVM ventilation to an 11% increased risk of dying with BVM. For good neurological outcome the range was similar with a range from a 38% decreased risk of bad neurological outcome from BVM to a 22% increased risk of bad neurological outcome from BVM. Within subgroups there were several that for the CI did not cross one. Each of these (Child Maltreatment and Respiratory arrest for survival, and Foreign Body Aspiration for neurological outcome) showed improved outcome with BVM ventilation.

	ETI	BVM	OR, 95%CI
Child Maltreatment (survival)	3/22 (5%)	10/24 (24%)	0.07, 0.01-0.58
Respiratory Arrest (survival)	33/54 (61%)	46/54 (85%)	0.27, 0.11-0.69
Foreign Body Aspiration (good neurological outcome)	3/13 (23%)	9/13 (69%)	0.13, 0.02-0.76

IV. Will the results help me in caring for my patients?

1. Can the results be applied to my patient care?

Indirectly. While intensivists are trained in airway management, we often work with people who are at varying skill levels. This article would suggest that good bag-valve-mask ventilation by less skilled professionals until a higher level of skill is available is not detrimental to the patient.

2. Were all clinically important outcomes considered?

Yes.

3. Are the likely treatment benefits worth the potential harms and costs?

Clearly the amount of training, both from a time and money standpoint were dramatic in this study. This study would suggest that ignoring endotracheal tube instruction, and focusing on good Bag-Valve-Mask Ventilatory techniques is more important, more cost effective, and more beneficial for the patients.

Discussion

There are many elements to this study that make it intriguing, both from the concept of applying it to more general use, and trying to replicate it. There are issues with transport time, that can't be generalized from this study. What about patients who have long transport times? Some rural areas may have 45 minutes to an hour or even longer before the patient reaches someone skilled in pediatric airway. Can these patients be effectively maintained with BVM until then, or is this a group that would benefit from earlier ETI?

Another consideration is experience. It has already been demonstrated that people need retraining or ongoing experience to maintain skills (4). In this study involving over 3000 paramedics and students over a nearly 3 year period, there were only 830 pediatric patients who qualified for advanced airway management. This means that, at best, only 27% of the paramedics even participated in the study, suggesting that a paramedic might need to intubate a child once every 12 years or so. Since the success rate for intubation in this study was 57%, one wonders if enough was, or even can be done, to train people well enough for pediatric intubation. The other limitation this brings to light is the potential that variances in skill level among the paramedics can affect outcome. Since the results of the intervention depend on the ability of the operator, a better study would have had randomization for each paramedic, so that outcomes for the individual paramedics could be compared, thus using the paramedic as the unit of analysis (7).

References

1. Fiser DH. Assessing the outcome of Pediatric intensive care. J Pediatrics. 1992; 121:68-74. [abstract]
2. Losek JD, Szewczuga D, Glaeser PW. Improved prehospital pediatric ALS care after an EMT-paramedic clinical training course. Am J Emerg Med. 1994;12(4):429-32. [abstract]
3. Aijian P, Tsai A, Knopp R, Kallsen GW. Endotracheal intubation of pediatric patients by paramedics. Ann Emerg Med. 1989;18(12):1376. [abstract]
4. Henderson DP, Gausche M, Goodrich PD, Michael WB, Lewis JL. Education of paramedics in pediatric airway management: effects of different retraining methods on self-efficacy and skill retention. Acad Emerg Med. 1993;22:393-403. [no abstract available]
5. Stratton SJ, Kane G, Gunter CS. Prospective study of manikin-only versus manikin and human subject endotracheal intubation training of paramedics. Ann Emerg Med.1991;20:1314-1318. [abstract}
6. Glaeser P. Out-of hospital intubation of children (editorial). JAMA 2000;283: 797. [full-text for a limited time]
7. Divine GW; Brown JT; Frazier LMJ. Gen Intern Med 1992;7(6):623-9. [abstract]

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