Efficacy of a Hydrogel Pad Cooling Device for induction, maintenance, and rewarming during mild...
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Efficacy of a Hydrogel Pad Cooling Device for induction, maintenance, and rewarming during mild hypothermia treatment in the post cardiac arrest and neuro patient populations Mission Hospital – Mission Viejo CA 1 UCLA Los Angeles CA 2 Mary Kay Bader RN 1 , Teresa Wavra RN 1 , Robert McCary RN 2 , Joy Toyama MS 2 , George Schiffman MD 1 , and Jon Cline MD 1 Conclusion: Patients undergoing mild hypothermia were rapidly cooled to the goal temp of 32-34 °C within 2.5-2.8 hours using a hydrogel pad surface cooling device. Overshooting the target temperature occurred in 3 of the 40 patients. Rewarming to 37°C was well controlled in both populations. There were several patient records that had incomplete clinical data therefore they were not included in the statistical analysis. Overall, the organizations cooling method and protocol were able to deliver a well controlled hypothermia treatment while Results: 28 post cardiac arrest patients and 28 neuro patients had orders to induce mild hypothermia starting in September 2006. 16 patients were excluded due to: a) target temperature ordered to 35°C [6 neuro], b) no available medical record [3], c) hemodynamic instability leading to aborted procedures [3 cardiac], d) poor documentation [3] with inability to obtain accurate data, and e)1st documented temperature of 33°C with incomplete documentation [3]). Data from 40 patients were included for analysis. In the neuro patients, mean values were 43.1 (age), 23.59 (BSA) and 1.866 (BMI). In the cardiac patients, mean values were 58.7 (age), 27.675 (BSA), and 2.024 (BMI). Induction cooling time to target of 33°C was 2.575 hours with a mean cooling rate of 1.43°C/hr for the neuro patients and 2.8 hours with a mean cooling rate of 1.2°C/hr for the cardiac patients. Using the Pearson Correlation, a significant association between the degree/hr decrease for both BMI and BSA was determined: BMI p-value= 0.40568; BSA p- value= 0.45674 at a significant level of p=0.05. Overshooting the lower temperature threshold of 32°C occurred in 0 of 20 neuro patients and 3 of 20 cardiac patients with the lowest temperature recorded at 31.5°C. Rewarming rates were well controlled for both populations (0.25°C/hour in cardiac patients/spinal injury and 0.05°C/hour in brain injury patients). Introduction: The implementation of mild hypothermia (32- 34°C) in post cardiac arrest (HACA) ameliorates the hypoxic/anoxic damage in the brain. Mild hypothermia has been deployed in neuro patients with refractory increased intracranial pressure, severe vasospasm, stroke, and injury to the brain/spine. The challenge in implementing this therapy is using a cooling system that rapidly induces the target temperature of 32-34°C without overshooting the temperature, maintaining the target temperature, and rewarming slowly to reduce rebound cerebral swelling and minimize the electrolyte shifts that occur as patients return to 37°C. This study examined two patient populations at one community hospital where mild hypothermia was used to reduce neurologic injury post cardiac arrest and in critical neuro patients using a hydrogel pad surface cooling system. Methods: A retrospective review of all patients treated with mild hypothermia post-cardiac arrest or for severe neurologic injury over the last three years was conducted. An analysis of the medical records was done. Data abstracted included age, body surface area (BSA), and body mass index (BMI) as well as bladder temperatures obtained every 15 to 60 minutes during the hypothermia period. Induction time (defined as the active rate of cooling from start to target temperature), overshooting target temperature (defined as temperatures below 32°C) and control of rewarming at the prescribed rate were assessed. HACA Patient Population Individual Temperature Curves Variable M ean Std Error N A ge Sex Ht__cm _ Wt__kg_ BM I__kg_m 2_ BSA __m 2_ Temp_at_start_of_Induction__fole Post_induction_Foley_Temp__C_ time_hrs deg_hr 43.1500000 1.3684211 174.2520000 72.2250000 23.5900000 1.8660000 36.2800000 33.1150000 2.5750000 1.4322604 3.9975486 0.1136972 1.6426387 3.4423361 0.8568271 0.0534711 0.2025625 0.0264326 0.4144194 0.1062931 20 20 20 20 20 20 20 20 20 20 Variable Analysis Neuro Population HACA Population P earso n C o rrelatio n C o efficien ts, N = 20 one-sided pvalue under H 0 : R ho= 0 Age BM I__kg_m 2_ BSA__m 2_ tim e_ hrs deg_hr Age Age 1.00000 -0.10285 0.33305 0.00520 0.49135 0.00441 0.49265 0.07214 0.38125 BM I__kg_m 2_ B M I (k g / m 2) -0.10285 0.33305 1.00000 0.91036 < .0001 0.40568 0.038 -0.51840 0.0096 BSA__m 2_ B SA (m 2) 0.00520 0.49135 0.91036 < .0001 1.00000 0.45674 0.02145 -0.60547 0.00235 tim e_ hrs 0.00441 0.49265 0.40568 0.038 0.45674 0.02145 1.00000 -0.62497 0.0016 deg_hr 0.07214 0.38125 -0.51840 0.0096 -0.60547 0.00235 -0.62497 0.0016 1.00000 P earso n C o rrelatio n C o efficie n ts, N = 20 one-sided pvalue under H 0 : R ho= 0 Age BM I__kg_m 2_ BSA__m 2_ tim e_ h rs deg_hr Age Age 1.00000 0.29880 0.10035 -0.22271 0.17265 -0.23743 0.15675 0.10128 0.33545 BM I__kg_m 2_ B M I (kg / m 2) 0.29880 0.10035 1.00000 0.23937 0.1547 0.29946 0.0998 -0.25187 0.14205 BSA__m 2_ B SA (m 2) -0.22271 0.17265 0.23937 0.1547 1.00000 0.44290 0.02525 -0.73090 0.00015 tim e_ hrs -0.23743 0.15675 0.29946 0.0998 0.44290 0.02525 1.00000 -0.64195 0.00115 deg_hr 0.10128 0.33545 -0.25187 0.14205 -0.73090 0.00015 -0.64195 0.00115 1.00000 Statistical Analysis Neuro Population HACA Population [email protected] [email protected] Variable M ean Std Error N A ge Sex Ht__cm _ Wt__kg_ BM I__kg_m 2_ BSA __m 2_ Temp_at_start_of_Induction__fole Post_induction_Foley_Temp__C_ time_hrs deg_hr 58.2000000 1.2500000 176.5500000 86.0580000 27.6750000 2.0240000 36.0750000 33.0000000 2.8000000 1.2011550 3.0971974 0.0993399 1.8020529 2.8007848 0.7780162 0.0521001 0.2237098 0.0369922 0.2530082 0.0934018 20 20 20 20 20 20 20 20 20 20 Neuro Patient Population Individual Temperature Curves Poster 353
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Transcript of Efficacy of a Hydrogel Pad Cooling Device for induction, maintenance, and rewarming during mild...
Efficacy of a Hydrogel Pad Cooling Device for induction, maintenance, and rewarming during mild hypothermia treatment in the post cardiac arrest and neuro patient populations
Mission Hospital – Mission Viejo CA1 UCLA Los Angeles CA2
Mary Kay Bader RN1, Teresa Wavra RN1, Robert McCary RN2, Joy Toyama MS2 , George Schiffman MD1, and Jon Cline MD1
Conclusion:Patients undergoing mild hypothermia were rapidly cooled to the goal temp of 32-34 °C within 2.5-2.8 hours using a hydrogel pad surface cooling device. Overshooting the target temperature occurred in 3 of the 40 patients. Rewarming to 37°C was well controlled in both populations. There were several patient records that had incomplete clinical data therefore they were not included in the statistical analysis. Overall, the organizations cooling method and protocol were able to deliver a well controlled hypothermia treatment while minimizing overshooting of the target temperature.
Results:28 post cardiac arrest patients and 28 neuro patients had orders to induce mild hypothermia starting in September 2006. 16 patients were excluded due to: a) target temperature ordered to 35°C [6 neuro], b) no available medical record [3], c) hemodynamic instability leading to aborted procedures [3 cardiac], d) poor documentation [3] with inability to obtain accurate data, and e)1st documented temperature of 33°C with incomplete documentation [3]). Data from 40 patients were included for analysis. In the neuro patients, mean values were 43.1 (age), 23.59 (BSA) and 1.866 (BMI). In the cardiac patients, mean values were 58.7 (age), 27.675 (BSA), and 2.024 (BMI). Induction cooling time to target of 33°C was 2.575 hours with a mean cooling rate of 1.43°C/hr for the neuro patients and 2.8 hours with a mean cooling rate of 1.2°C/hr for the cardiac patients. Using the Pearson Correlation, a significant association between the degree/hr decrease for both BMI and BSA was determined: BMI p-value= 0.40568; BSA p-value= 0.45674 at a significant level of p=0.05. Overshooting the lower temperature threshold of 32°C occurred in 0 of 20 neuro patients and 3 of 20 cardiac patients with the lowest temperature recorded at 31.5°C. Rewarming rates were well controlled for both populations (0.25°C/hour in cardiac patients/spinal injury and 0.05°C/hour in brain injury patients).
Introduction:The implementation of mild hypothermia (32-34°C) in post cardiac arrest (HACA) ameliorates the hypoxic/anoxic damage in the brain. Mild hypothermia has been deployed in neuro patients with refractory increased intracranial pressure, severe vasospasm, stroke, and injury to the brain/spine. The challenge in implementing this therapy is using a cooling system that rapidly induces the target temperature of 32-34°C without overshooting the temperature, maintaining the target temperature, and rewarming slowly to reduce rebound cerebral swelling and minimize the electrolyte shifts that occur as patients return to 37°C. This study examined two patient populations at one community hospital where mild hypothermia was used to reduce neurologic injury post cardiac arrest and in critical neuro patients using a hydrogel pad surface cooling system.
Methods:A retrospective review of all patients treated with mild hypothermia post-cardiac arrest or for severe neurologic injury over the last three years was conducted. An analysis of the medical records was done. Data abstracted included age, body surface area (BSA), and body mass index (BMI) as well as bladder temperatures obtained every 15 to 60 minutes during the hypothermia period. Induction time (defined as the active rate of cooling from start to target temperature), overshooting target temperature (defined as temperatures below 32°C) and control of rewarming at the prescribed rate were assessed.
HACA Patient Population Individual Temperature
Curves
Variable Mean Std Error N
Age
Sex
Ht__cm_
Wt__kg_
BMI__kg_m2_
BSA__m2_
Temp_at_start_of_Induction__fole
Post_induction_Foley_Temp__C_
time_hrs
deg_hr
43.1500000
1.3684211
174.2520000
72.2250000
23.5900000
1.8660000
36.2800000
33.1150000
2.5750000
1.4322604
3.9975486
0.1136972
1.6426387
3.4423361
0.8568271
0.0534711
0.2025625
0.0264326
0.4144194
0.1062931
20
20
20
20
20
20
20
20
20
20
Variable AnalysisNeuro Population HACA Population
Pearson Correlation Coefficients, N = 20 one-sided pvalue under H0: Rho=0
Age BMI _ _ kg_ m2_ BSA_ _ m2_ time_ hrs deg_ hr
Age Age
1.00000
-0.10285 0.33305
0.00520 0.49135
0.00441 0.49265
0.07214 0.38125
BMI _ _ kg_ m2_ BMI (kg/ m2)
-0.10285 0.33305
1.00000
0.91036 <.0001
0.40568 0.038
-0.51840 0.0096
BSA_ _ m2_ BSA (m2)
0.00520 0.49135
0.91036 <.0001
1.00000
0.45674 0.02145
-0.60547 0.00235
time_ hrs
0.00441 0.49265
0.40568 0.038
0.45674 0.02145
1.00000
-0.62497 0.0016
deg_ hr
0.07214 0.38125
-0.51840 0.0096
-0.60547 0.00235
-0.62497 0.0016
1.00000
Pearson Correlation Coefficients, N = 20 one-sided pvalue under H0: Rho=0
Age BMI_ _ kg_ m2_ BSA_ _ m2_ time_ hrs deg_ hr
Age Age
1.00000
0.29880 0.10035
-0.22271 0.17265
-0.23743 0.15675
0.10128 0.33545
BMI_ _ kg_ m2_ BMI (kg/ m2)
0.29880 0.10035
1.00000
0.23937 0.1547
0.29946 0.0998
-0.25187 0.14205
BSA_ _ m2_ BSA (m2)
-0.22271 0.17265
0.23937 0.1547
1.00000
0.44290 0.02525
-0.73090 0.00015
time_ hrs
-0.23743 0.15675
0.29946 0.0998
0.44290 0.02525
1.00000
-0.64195 0.00115
deg_ hr
0.10128 0.33545
-0.25187 0.14205
-0.73090 0.00015
-0.64195 0.00115
1.00000
Statistical AnalysisNeuro Population HACA Population
[email protected] [email protected]
Variable Mean Std Error N
Age
Sex
Ht__cm_
Wt__kg_
BMI__kg_m2_
BSA__m2_
Temp_at_start_of_Induction__fole
Post_induction_Foley_Temp__C_
time_hrs
deg_hr
58.2000000
1.2500000
176.5500000
86.0580000
27.6750000
2.0240000
36.0750000
33.0000000
2.8000000
1.2011550
3.0971974
0.0993399
1.8020529
2.8007848
0.7780162
0.0521001
0.2237098
0.0369922
0.2530082
0.0934018
20
20
20
20
20
20
20
20
20
20
Neuro Patient Population Individual Temperature Curves
Poster 353
