The results of our survey suggest that Canadian ICU physicians commonly use crystalloid fluids such as normal saline and ringers lactate, and the colloidal fluid pentastarch for early septic shock resuscitation; use of albumin is reportedly much less frequent. Blood pressure and urine output were cited as the two most common volume resuscitation end-points. Among different specialties, physicians also appear to have divergent fluid resuscitation preferences; indeed, anesthesiologists and surgeons reported greater use of Ringers lactate than did internists. Compared with internists, anesthesiologists also more frequently reported using a low hemoglobin transfusion trigger of 80 g/l or less.
Interestingly, only 10% of Canadian ICU physicians stated that they would use continuous measurements of ScvO2
even if this monitoring parameter was available for early septic shock. However, 53% said that they would use intropic agents, and all physicians stated they would transfuse patients in response to a low ScvO2
. These responses suggest that although physicians may infrequently use continuous monitoring of ScvO2
, they may use it intermittently or in some patients to help guide therapy. We conclude that the protocol presented by Rivers and coworkers [6
] for early septic shock resuscitation has been variably adopted by Canadian ICU physicians, perhaps for several reasons.
Although it was a well conducted landmark trial in goal-directed resuscitation, supported by the Surviving Sepsis Campaign Guidelines for management of severe sepsis and septic shock [10
], it was a single-center study and has not yet been replicated. Although some centers have evaluated and adopted this early goal-directed resuscitation protocol as part of their clinical practice [11
], many questions remain. The benefit seen in the early goal-directed group may have been due to expedient resuscitation rather than continuous monitoring of ScvO2
]. Indeed, one explanation for the negative results of the goal-directed resuscitation trial conducted by Gattinoni and coworkers [18
], which incorporated ScvO2
as a resuscitation end-point, as compared with the trial reported by Rivers and coworkers could be the time to initiate goal-directed therapy. Rivers and colleagues randomized patients into the study within 1 hour of arrival in the emergency room, whereas Gattinoni and coworkers enrolled patients within 48 hours of admission to the ICU [17
]. Furthermore, it is unclear whether intermittent as compared with continuous ScvO2
monitoring is sufficient to detect low ScvO2
in early septic shock. Another reason for reported low adoption of continuous monitoring of ScvO2
may relate to lack of resources. In a survey of 30 academic emergency room physicians from the USA, only 7% reported use of early goal-directed therapy in the emergency room. Major reported barriers for implementation of early goal-directed therapy included the need for specialty monitoring equipment (75%), amount of resources needed (43%), the need for central venous catheter cannulation (36%), and too much emergency physician time required (29%) [19
The use of RBCs to augment oxygen delivery when the ScvO2
was below 70% was a controversial aspect of the Rivers resuscitation algorithms. Results of our survey suggested that only 7% of physicians would transfuse at a hemoglobin of 100 g/l, and 75% stated they would transfuse at a target hemoglobin that was as low as 80 g/l or less. An important reason for accepting a lower RBC transfusion trigger in the critically ill patient population probably relates to evidence from the Canadian led Transfusion in Critically Ill (TRICC) trial [20
], which demonstrated a lower transfusion trigger (hemoglobin 70 g/l) was just as effective as a more conservative transfusion trigger (hemoglobin 90 g/l). However, results from the TRICC trial may not apply to patients with early septic shock, because patients with sepsis represented only 5% of the TRICC patient population [21
]. Furthermore, the study by Rivers and coworkers did not specifically address the question of an optimal RBC transfusion trigger in this setting, and hence it is difficult to know whether this liberal transfusion trigger was responsible for the mortality benefit seen in the goal-directed group.
Half of our survey respondents indicated that they would start an inotropic agent in response to a low ScvO2
. Lack of a uniform response may be related to concerns that use of these agents could potentially worsen myocardial oxygen consumption and cardiac arrhythmias in the setting of a heart that is already in high demand [22
]. Furthermore, because the study by Rivers and coworkers was not specifically designed to test whether an inotropic agent improved outcome, it is difficult to know whether the contribution of inotropes, among many other components of the protocol in the intervention arm, was primarily responsible for the mortality benefit seen in the goal-directed group.
We found heterogeneous responses with regard to choice of resuscitation fluids in early septic shock. Although normal saline, Ringers lactate, and the colloid pentastarch were used at least 50% of the time, the use of either 5% or 25% albumin was infrequent. Reasons for minimal use of albumin may be related to the findings of a previous meta-analysis that suggested that albumin was not beneficial and was potentially harmful [24
]. However, results from the Saline versus 4% Albumin Fluid Evaluation (SAFE) study has put some of this controversy to rest [25
]. That study was a randomized controlled trial of 6,997 heterogeneous critically ill patients in need of volume resuscitation, which compared 4% albumin with normal saline. It found no difference in 28-day mortality between the two groups, but there was a trend toward lower mortality in a subgroup of patients with severe sepsis who received albumin (relative risk ratio of 0.87, 95% CI 0.74 to1.02). The results of this subgroup analysis have served to fuel the debate with regard to superiority of colloidal as compared with crystalloid fluid resuscitation in the setting of severe sepsis and septic shock, and call for a large prospective, randomized trial to confirm or refute this hypothesis.
Our survey examined stated adult ICU physician resuscitation practices within the context of early septic shock. There are four previously published critical care surveys. Two reflect European [26
] and two reflect Canadian [28
] and USA resuscitation practices [19
]. The Canadian and European surveys focused specifically on choice of resuscitation fluids and rationale for these choices in heterogeneous critically ill patient populations. The US survey reported on the use and barriers to implementation of early goal-directed therapy [19
], as compared with our survey, which elicited stated practices for both resuscitation monitoring techniques and numerous therapeutic interventions.
There are several potential limitations to the methods used in this study, including response bias and response rate. For example, the use of a hypothetical scenario may have resulted in critical care physicians stating that they use resuscitation parameters similar to those described by Rivers and coworkers more often than in actual practice. It is also possible that one of our questions on the RBC transfusion trigger might have prompted reports of a more restrictive transfusion trigger because we, the survey investigators, had conducted the only major randomized trial in this field. It is difficult to predict how the 35% of individuals who did not respond may have answered the questions and influenced the results and interpretation of the findings. However, it is difficult to speculate whether the nonresponding physicians would be entirely homogeneous and sufficiently different in their answers, and thus impact on our overall results. The universal caveat for all surveys holds for this one as well; what physicians say they do may not reflect what they actually do.
This survey examined the very topical issue of resuscitation in septic shock, a condition associated with high mortality. We surveyed physicians with different base specialties in university affiliated and community hospitals. Although surveys of stated practice may not reflect actual practice [8
], it is important to conduct surveys early in research programs designed to address vexing problems such as resuscitation strategies, because they provide essential background information for the design of these trials.