Prospective Trial of Supranormal Values of Survivors as Therapeutic Goals in High-Risk Surgical Patients: Experimental Design

In: Surgical Patients

11 Mar 2015

Prospective Trial of Supranormal Values of Survivors as Therapeutic Goals in High-Risk Surgical Patients: Experimental DesignExperimental Design
In series 1, patients were prospectively allocated to either a protocol or control service. One or two of the three adult general surgical services were prospectively designated as control services and the other one or two services as the protocol service according to a prearranged schedule developed prior to the beginning of each academic year; the protocol service was rotated to each of the three services and the principal investigator was also rotated between protocol and control services. The protocol group used supranormal therapeutic goals and was comprised of patients who were admitted when residents on the protocol services were on duty; the control group was comprised of patients treated by residents on the control services using normal values as goals (Table 2). Previous studies have documented comparable severity of illness and mortality among the three services.

In series 1, the diagnoses, operations, age (control), 56 ±21; protocol, 51 ±19 [SD] years), gender (control, 61 percent males; protocol, 66 percent males), lowest blood pressure (control, 55 ± 24 mm Hg; protocol, 53 ±22 mm Hg), time in hypotension (control, 2.2 ± 2.5 h; protocol, 2.4 ±2.3 h), mean arterial pressures <50 mm Hg (control, 39 percent; protocol, 44 percent), and distribution of high risk factors (Table 1) were comparable between the two groups. life without allergy com
In series 2, patients were preoperatively randomized to one of three catheter/treatment groups: (a) CVP-control group: CVP-cath-eter placement and perioperative management using the normal values of standard clinical parameters available by CVP as therapeutic goals, (b) PA-control group: pulmonary artery catheter placement and management using normal values of hemodynamic and oxygen-transport variables available by PA catheter monitoring as the goals of therapy, and (c) PA-protocol group: PA catheter placement using supranormal hemodynamic and oxygen-transport values as the goals of therapy (Table 2). The monitoring team assisted the primary service in placing the catheters and in obtaining the measurements, but they had no direct clinical responsibility for patient management in any of the groups.
Table 2—Therapeutic Goals for Groups

Variable, Units CVP and NR Groups PA-Control PA-Protocol
Similar goals for control and protocol groups
Blood pressure, mm Hg >120/80 >120/80 >120/80
CV£ cm saline >4 and <12 >4 and <12 <15
Hct, % >35 >35 >34
UO, ml/ll >30 >30 >30
HR, beats per minute >60 and <120 >60 and <120 >60 and <120
Temperature, F <102° <102° <102°
Pa02, torr >70 >70 >70
pH >7.3 and <7.5 >7.3 and <7.5 >7.3 and <7.5
PvOa, torr >40 >40
PA pressure, mm Hg >25/10 >25/10
Pulmonary VVP, mm Hg 4-12 <18
Systemic vascular resistance, dyne^s/cm^m2 1800-2600 >1450
Pulmonary vascular resistance, dyne^s/cm^m2 45-250 45-250
Oxygen extraction, % … 22-30 22-30
Major differences in the goals for control and protocol groups
Cl, L/min#m2 2.8-3.5 >4.5
DOz, ml/min*m2 400-550 >600
Vo2, ml/minnn2 120-140 >170

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