Passive Leg Raising Attenuates and Delays Tourniquet Deflation-induced Hypotension and Tachycardia
|First Received Date ICMJE||March 30, 2012|
|Last Updated Date||May 4, 2012|
|Start Date ICMJE||September 2010|
|Primary Completion Date||August 2011 (final data collection date for primary outcome measure)|
|Current Primary Outcome Measures ICMJE
||Change from Baseline in Blood pressure [ Time Frame: Baseline and 60 min ] [ Designated as safety issue: Yes ]
The patients' blood pressure was measured before, during, and after tourniquet deflation. Step 1 (T1-T5), measurements were taken at 30, 15, 10, 5, and 1 min before bilateral passive leg raising (PLR). Step 2 (T6-T7), measurements were taken 2 and 4 min after initiation of PLR. Step 3 (T8-T10), measurements were taken at 2, 4, and 6 min after tourniquet deflation. Step 4 (T11-T17), measurements were obtained 1, 3, 5, 10, 15, 30, and 60 min later. Hemodynamic measurements and change were analyzed over time by comparing the T6-T17 measurements to the T5 measurements in each group.
|Original Primary Outcome Measures ICMJE||Same as current|
|Change History||Complete list of historical versions of study NCT01592669 on ClinicalTrials.gov Archive Site|
|Current Secondary Outcome Measures ICMJE
||Heart rate [ Time Frame: up to 60 min ] [ Designated as safety issue: Yes ]
The patients' heart rate was measured before, during, and after tourniquet deflation. Step 1 (T1-T5), measurements were taken at 30, 15, 10, 5, and 1 min before bilateral passive leg raising (PLR). Step 2 (T6-T7), measurements were taken 2 and 4 min after initiation of PLR. Step 3 (T8-T10), measurements were taken at 2, 4, and 6 min after tourniquet deflation. Step 4 (T11-T17), measurements were obtained 1, 3, 5, 10, 15, 30, and 60 min later.Hemodynamic measurements and change were analyzed over time by comparing the T6-T17 measurements to the T5 measurements in each group.
|Original Secondary Outcome Measures ICMJE||Same as current|
|Current Other Outcome Measures ICMJE||Not Provided|
|Original Other Outcome Measures ICMJE||Not Provided|
|Brief Title ICMJE||Passive Leg Raising Attenuates and Delays Tourniquet Deflation-induced Hypotension and Tachycardia|
|Official Title ICMJE||The Effect of Passive Leg Raising or Experimental Clinical Practices on the Prevention of Hypotension Following Tourniquet Release in Total Knee Arthroplasty Patients|
The pneumatic tourniquet is frequently used in total knee arthroplasty. Tourniquet deflation may result in hypotension and tachycardia caused by the rapid shift of blood volume back to the ischemic limb and a decrease in cardiac preload. Passive leg raising (PLR) represents a "self-volume challenge" that can result in an increase in preload. Such a PLR-induced increase in preload was hypothesized to attenuate the decrease in preload resulting from tourniquet deflation. This study was designed to evaluate the effect of PLR on hypotension and tachycardia following tourniquet deflation.
Seventy patients who underwent unilateral total knee arthroplasty were assigned to either the bilateral PLR group (n = 35) or the control group (n = 35), in a prospective randomized trial. The patients' blood pressure and heart rate were measured before, during, and after tourniquet deflation.
This study was a prospective randomized trial, which was approved by the Institutional Review Board of the hospital, and informed consent was obtained from each patient enrolled in the study. Patients with degenerative joint disease of the knee scheduled to receive unilateral total knee arthroplasty were enrolled in this study within one year. Exclusion criteria were bilateral total knee arthroplasty, previous knee surgery, cardiac arrhythmia, uncontrolled hypertension (systolic blood pressure > 170 mmHg), presence of a known aortic aneurysm, recent stroke or myocardial infarction, unstable angina pectoris, New York Heart Association functional class III or IV, and American Society of Anesthesiologists physical status IV to V. A series of numbered, opaque, sealed envelopes were used to randomly allocate participants to the bilateral PLR group (n = 35) or to the control group (n = 35). The trial flow chart is illustrated in Figure 1. The primary outcome measures were the blood pressure and heart rate before, during, and after tourniquet deflation.
The sample size estimate, based on previous studies8, indicated that 35 patients were required for each group in order to have a 90% chance of detecting a significant difference (P = 0.05, two-sided) between the groups. Patients were premedicated with fentanyl and/or midazolam for anxiolysis 5 min before induction of anesthesia. Spinal anesthesia was performed via the L3-L4 or L4-L5 interspace with a single dose of isobaric bupivacaine. A drop in systolic blood pressure to lower than 90 mmHg triggered ephedrine administration during the study.
Figure 2 illustrates the study protocol, which was divided into 4 steps. Blood pressure and heart rate were measured at each time point (T1-T17) throughout the protocol. Systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean blood pressure (MBP) were measured using noninvasive, automated techniques and a continuous electrocardiogram allowed measurements of heart rate. In addition, the doses of bupivacaine and ephedrine administrated, as well as the upper anesthetized level, and total fluid volume administered before tourniquet deflation were recorded.
Step 1 (T1-T5): In both groups, after induction of spinal anesthesia, the patient was placed in a supine position with a well-padded proximal tourniquet. The leg was exsanguinated with an Esmarch bandage, and a pneumatic tourniquet was applied and inflated to a pressure of 280-300 mm Hg, followed by the arthroplastic surgery. Recordings and measurements were taken at 30, 15, 10, 5, and 1 min before bilateral PLR (step 2).
Step 2 (T6-T7): In the PLR group, at the completion of the total knee arthroplasty, bilateral PLR was achieved by raising the patient's legs to a 45 degree angle. Recordings and measurements were taken 2 and 4 min after initiation of PLR. In the control patients, the legs were left in the baseline position, but hemodynamic measurements were still taken at time points corresponding to those in the PLR group.
Step 3 (T8-T10): In the PLR group, PLR was maintained and the tourniquet was deflated and hemodynamic recordings and measurements were taken at 2, 4, and 6 min after tourniquet deflation. At this step, blood pressure and heart rate were recorded for 6 min because previous reports have suggested that the nadir of the blood pressure occurred within 5 min after tourniquet deflation. In the control group, the tourniquet was deflated while the patient's legs remained in the baseline position and hemodynamic measurements were obtained at points corresponding to those in the PLR patients.
Step 4 (T11-T17): In the PLR group, the legs were returned to the baseline position and a fourth set of recordings and hemodynamic measurements were obtained 1, 3, 5, 10, 15, 30, and 60 min later. In the control group, the legs remained in the baseline position and corresponding hemodynamic measurements were obtained.
Statistical Methods Differences in demographic characteristics and perioperative data between the PLR and control patients were examined using chi-square or Student's t tests, depending on the measure. Hemodynamic measurements were analyzed over time by comparing the T6-T17 measurements to the T5 measurements in each group. Intragroup hemodynamic changes were analyzed using repeated measures one-way analysis of variance, followed by the Fisher's least-significant difference post-test. The generalized estimating equations test was used to compare the differences between groups (PLR and control group), with respect to blood pressure and heart rate measurements. The difference in the length of time from tourniquet deflation to the nadir in blood pressure between the groups was determined by Student's t test. The SPSS software (Version 15 SPSS Inc., Chicago, Illinois) was used for all analyses. All the tests were two-sided, and P < 0.05 was considered significant.
|Study Type ICMJE||Interventional|
|Study Phase||Not Provided|
|Study Design ICMJE||Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Open Label
Primary Purpose: Prevention
|Intervention ICMJE||Procedure: passive leg raising
bilateral PLR was achieved by raising the legs of patient
Other Name: PLR
|Study Arm (s)||
|Publications *||Not Provided|
* Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
|Recruitment Status ICMJE||Completed|
|Completion Date||August 2011|
|Primary Completion Date||August 2011 (final data collection date for primary outcome measure)|
|Eligibility Criteria ICMJE||
|Ages||60 Years to 90 Years|
|Accepts Healthy Volunteers||No|
|Contacts ICMJE||Contact information is only displayed when the study is recruiting subjects|
|Location Countries ICMJE||Taiwan|
|NCT Number ICMJE||NCT01592669|
|Other Study ID Numbers ICMJE||TSGH-C101-105|
|Has Data Monitoring Committee||Yes|
|Responsible Party||Go-Shine Huang, Tri-Service General Hospital|
|Study Sponsor ICMJE||Tri-Service General Hospital|
|Collaborators ICMJE||Not Provided|
|Information Provided By||Tri-Service General Hospital|
|Verification Date||May 2012|
ICMJE Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP