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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Early Reversal of Pediatric-Neonatal Septic Shock by Community Physicians Is Associated With Improved Outcome.

Han YY, Carcillo JA, Dragotta MA, et al.

Pediatrics 2003;112 793-799. [abstract]

Reviewed by Nesreen Faquih MD, Texas Children's Hospital, Houston TX (currently: King Hussein Cancer Center, Amman, Jordan)

Review posted February 2, 2004

I. What is being studied?

Study objective:

To determine whether early septic shock reversal and use of resuscitation practice consistent with the new ACCM-PALS guidelines by community physicians is associated with improved outcome.

Study design

A retrospective cohort study where the transport data for Children's Hospital of Pittsburgh (CHP) was reviewed for 9 years from January 1993 to Dec 31, 2001 for patients with sepsis.

Patients included:

From 6196 transports, 186 were children with sepsis, of whom 91 met the criteria of septic shock. The criteria for inclusion included the following:

1. Patients were transported to CHP by CHP pediatric critical care transport team
2. Patients met the clinical criteria for septic shock which was defined by suspected infection as manifested by hyperthermia or hypothermia and signs of decreased perfusion, including decreased mental status, prolonged capillary refill time, diminished peripheral pulses, or mottled extremities. The presence of hypotension and use of inotropic/vasopressor infusions to maintain normotension were considered as confirmatory signs for decreased perfusion.

Patients excluded:

Premature infants < 36 weeks corrected gestational age.

Outcomes assessed:

1. Shock reversal defined by normal systolic blood pressure and capillary refill
2. Resuscitation practice concurrence with ACCM-PALS guideline
3. Hospital mortality

II. Are the results of the study valid?

1. Are the outcome measures accurate and comprehensive?

The authors did a retrospective review of CHP transports team interfacility transport database and identified infants and children with sepsis through a query of the data base. Then records were retrieved to determine patients that met the criteria for septic shock. The authors divided the patients into survivors and non-survivors and looked into reversal of shock using "rather objective" clinical criteria including normalization of systolic blood pressure and capillary refill. Low blood pressure was not considered a necessary criterion for the definition of shock but was rather a confirmatory sign, though normalization of the systolic blood pressure was required for the definition of shock reversal. More accurate measures of reversal shock have been used similar to the study conducted in adults by Emaneul Rivers et al (1), where very specific criteria were used to identify reversal of shock as CVP, urinary output/kg/hour, MAP, and central venous pressure saturations.

The authors did explain how the data was collected from the database and on the time points at which clinical assessments were extracted from transport records, but how complete and accurate the data is not clear, considering that it's a retrospective data collection from transport records.

2. Were the comparison groups similar with respect to important determinants of outcome, other than the one of interest, and were residual differences adjusted for in the analysis?

When was the service provided?

The service was provided to infants and children in the time frame from Jan 1993 to Dec 2001. It was assumed that patients presented to the community hospital at the time of onset of their symptoms, but it's not certain when each child became ill and how long the child had been in shock before being brought to medical attention. In addition to that it's not certain when in relation to patients' presentation the request for interfacility transport by the community hospital physician was made.

Where was the service provided?

The service was provided at community hospitals. The characteristics of these hospitals were not mentioned. The only known information was that there was a request for transport to a tertiary hospital leading to the conclusion that maybe only severe cases were selected from each hospital and the less severe cases were not transferred, thus the sample of patients was not truly representative of septic shock. There is also a significant degree of variability among local hospitals and varied pediatric experience.

Who provided the service?

The service was provided by community physicians and the critical care transport team of CHP. It was not clear from the study whether the community hospital physicians had the same specialty, same level of experience or not and whether resuscitation was more successful with experienced physicians.

Follow up resuscitation was performed by the transport team. Physician accompaniment on the transport was similar with both survivors and non survivors (86% in survivor group versus 88% in the non-survivor group).

2. Determining whether differences in prognosis, rather than differences in the intervention, explain differences in outcomes

Did the investigators measure all known important prognostic factors?

Yes. The investigators looked into the characteristics of patients who presented with septic shock, and there were no differences in both the survivor versus the non survivor group including age, sex, the presence of a comorbid condition, culture sensitive sepsis, the presence of a physician on the transport, time to transport team arrival at the community hospital, and total transport time. The only difference was in the PRISM score to which outcomes were adjusted to by a multiple logistic regression analysis. All prognostic factors as the reversal of shock, resuscitation consistent with ACCM-PALS guidelines, the duration of shock per 1-hour increments and delay in resuscitation consistent with ACCM-PALS per 1 hour increments were measured and adjusted to the PRISM score.

Were measures of patients' prognostic factors reproducible and accurate?

Data was collected by medical record abstraction. There was no mention in the study of attempts to confirm accuracy or reliability of the data.

Did the investigators show the extent to which patients differed on these factors?

The demographics of the patients did not differ that much, the major difference was in the PRISM score which the prognostic factors were adjusted to.

Did the researchers use some form of multivariate analysis to adjust for all the important prognostic factors?

Yes. A multiple logistic regression analysis adjusted to PRISM score showed that when shock was reversed there was a > 9-fold increased odds of survival. Also when community hospital physicians implemented therapies consistent with ACCM-PALS guidelines there was a > 6-fold increased odds for survival. With each hour of persistence of shock there was > 2-fold increased odds of mortality, and each hour delay in institution of resuscitation consistent with ACCM-PALS guidelines was associated with a 50% increased odds of mortality.

III. What are the results?

1. What are the recommendations?

When resuscitation by community physicians was performed consistent with the ACCM-PALS guidelines survival rate was 92% versus 62% rate among patients who did not receive resuscitation consistent with the guidelines. Thus there was > 6 fold increased odds of survival adjusted for PRISM score (95% confidence interval 1.26-36.8). Community physicians implemented therapies consistent with the guidelines in only 30% of the patients. Appropriate fluid therapy was only administered in 45%; patients with resistant shock received appropriate fluid therapy in only 4%.

Shock reversal was associated with more than 9 fold increased odds of survival with 95% confidence interval of 1.07-83.89. Each hour of persistent shock that passed was associated with a mortality odds ratio of 2.29, (95% confidence intervals 1.19-4.44), and a delay of resuscitation consistent with ACCM-PALS Guidelines was associated with a mortality odds ratio of 1.53, (95% confidence intervals 1.08-2.16). The confidence intervals suggest that the delay in resuscitation and the persistence of shock were strongly suggestive of poor outcome, similar to previous studies that showed that rapid and aggressive fluid resuscitation in the first hour of presentation was associated with improved outcome (2). The wide confidence interval for the increased odds of survival with shock reversal is likely due to the small sample size. The narrow confidence intervals for the decreased odds for survival with the delay in resuscitation and persistence of shock assure the reader that mortality is increased between 1.1 times, to as high as 4.4 times, the mortality rate for those without these variables.

Hydrocortisone was given to 13% of patients, and trended toward successful shock reversal among these patients (50% with hydrocortisone versus 23% without hydrocortisone, p = 0.074). Characteristics of the patients receiving hydrocortisone were not mentioned.

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

1. How will the recommendations help you?

Early reversal of shock and resuscitation consistent with ACCM-PALS recommendations was found to be associated with improved outcome. Taking into consideration the wideness of confidence intervals for both improved odds for survival with reversal of shock and adhering with the ACCM-PALS guidelines, it's still a noteworthy study.

In accordance with the study, I would stress to community physicians that aggressive and immediate resuscitation of infants and children with septic shock is the physicians' first priority rather than delaying resuscitation while awaiting transfer to a pediatric referral center, and further stress the importance of appropriate fluid resuscitation, and the use of inotropes when adequate fluid resuscitation has occurred.

Educational programs and future revision of ACCM-PALS guidelines as well as the PALS curriculum will need to address technical problems such as management of pediatric airway and obtaining CVL access that might be potential barriers in implementing the guidelines in the community hospital setting.

References

1. Rivers E, Nguyen B, Havstad S, Ressler J, Muzzin A, Knoblich B, Peterson E, Tomlanovich M: Early goal directed therapy in the treatment of severe sepsis and septic shock. N Engl J Med.2001;345:1368-1377. [abstract] See the PedsCCM EBJC Review, by S Thammasitboon, M Mcpherson
2. Carcillo J, Davis AL, Zaritsky A. Role of early fluid resuscitation in pediatric septic shock. JAMA. 1991;266:1242-1245. [abstract]

 

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