Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 1958 The pplica ation of certain methods for the determination of the presence of pain in the dog during decompression Russell Levoy Schelkopf Iowa State College Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Animal Sciences Commons, Physiology Commons, and the Veterinary Physiology Commons Recommended Citation Schelkopf, Russell Levoy, "The ppa lication of certain methods for the determination of the presence of pain in the dog during decompression " (1958). Retrospective Theses and Dissertations. 1653. https://lib.dr.iastate.edu/rtd/1653 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. •THE APPLICATION OF CERTAIN METHODS FOR THE DETERMINATION OF THE PRESENCE OF PAIN IN THE DOG DURING DECOMPRESSION by Russell Levoy Schelkopf A Dissertation Submitted to the Graduate Faculty in Partial Fulfillment of The Requirements for the Degree of DOCTOR OF PHILOSOPHY Major Subject: Veterinary Physiology Approved: Signature was redacted for privacy. In Charge of Major Work Signature was redacted for privacy. Signature was redacted for privacy. Dean of Graduate College Iowa State College 1958 ii TABLE OF CONTENTS Page INTRODUCTION 1 LITERATURE CITED k Thermal Stimulation as a Method for Studying Pain Threshold 5 Electrical Methods of Evoking Pain as a Means for Studying Pain Threshold 13 Mechanical Methods of Inducing Pain as a Method for Studying Pain Threshold 18 Chemical Stimulation as a Method for Studying Pain Threshold 20 The Effect of Analgesic Agents upon Pain 22 Euthanasia by Decompression 23 Surgical Measures for the Relief of Pain 26 EXPERIMENTAL PROCEDURE 32 Determination of the Pain Reaction Threshold by the Thermal Technique 32 Determination of the Pain Reaction Threshold by the Thermal Technique during Decompression 40 Determination of the Pain Reaction Threshold by Electrical Stimulation of the Canine Tooth M+ Decompression of Morphinized Animals 51 Division of the Lateral Spinothalamic Tracts 52 RESULTS AND DISCUSSION 69 Determination of the Pain Reaction Threshold with the Hardy-Wolff-Goodell Dolorimeter 69 Determination of the Pain Reaction Threshold with the Hardy-Wolff-Goodell Dolorimeter during Decompression Pain Reaction Thresholds Determined by Electrical Stimulation of the Teeth 83 Anxiety and Excitement Observed during Decom­ pression Pre- and Post-morphinization of the Experimental Animals 87 Observations of the Anxiety and Apprehension during Decompression Before and After Sever­ ing the Lateral Spinothalamic Tracts 91 SUMMARY AND CONCLUSIONS 96 ill Page LITERATURE CITED 101 LITERATURE REVIEWED BUT NOT CITED 109 ACKNOWLEDGMENTS 115 APPENDIX A 116 APPENDIX B 120 APPENDIX C: EXPLANATION OF APPENDIX 121 iv LIST OF TABLES Page Table 1. Time required for decompression of the experimental animal with the Euthanair 4l Table 2. The pain reaction thresholds with their means and ranges using the Hardy-Wolff- Goodell Dolorimeter 71 Table 3* Analysis of variance of the pain reaction thresholds applying the Hardy-Wolff-Goodell Dolorimeter to the cutaneous area of the right shoulder 72 Table 4. Analysis of variance of the pain reaction thresholds applying the Hardy-Wolff-Goodell Dolorimeter to the cutaneous area of the dorsal lumbar region 73 Table 5» The number of pain reaction thresholds and their means recorded at various decompression levels 76 Table 6. The total number of pain reaction thresh­ olds and their over-all means recorded at various decompression levels on 10 dogs 78 Table 7» Analysis of variance of pain reaction thresholds at various decompression levels 80a Table 8. The combination of independent tests of sig­ nificance of pain reaction thresholds at various decompression levels 81 Table 9» The pain reaction thresholds obtained by electrical stimulation of the teeth 84 Table 10. Analysis of variance of the pain reaction thresholds obtained by electrical stimula­ tion of the teeth 86 Table 11. The pain reaction threshold means before and after morphine administration using the Hardy-Wolff-Goodell Dolorimeter. Anxiety and apprehension observed during decompres­ sion are recorded before and after the injection of morphine 88 v Page Table 12. The amount of anxiety exhibited during depression and the pain reaction thresh­ olds recorded with the Hardy-Wolff- Goodell Dolorimeter observed before and after severing of the lateral spinothalamic tracts of the dog 92 Table 13. Bartlett's test for inter-dog homogeneity of variances of the pain reaction thresh­ olds applying the Hardy-Wolff-Goodell dolorimeter to the cutaneous area of the right shoulder 116 Table ik. Bartlett's test for inter-dog homogeneity of variances of the pain reaction thresh­ olds applying the Hardy-Wolff-Goodell dolorimeter to the cutaneous area of the dorsal lumbar region 117 Table 1$. Bartlett's test for intra-dog homogeneity of variances of pain reaction thresholds, for four dogs selected randomly from the ten in the decompression experiment 118 Table 16. A two-way analysis of variance of the pain reaction thresholds obtained from the de­ compression experiment when the dolori- metric projector was applied to the right shoulder area, with the two coordinates respectively, decompression level and dogs 120 Table 17. A two-way analysis of variance of the pain reaction thresholds obtained from the de­ compression experiment when the dolori- metric projector was appplied to the lumbar region, with the two coordinates respectively, decompression level and dogs 120 vi LIST OF FIGURES Page Figure 1. Hardy-Wolff-Goodell Dolorimeter 34 Figure 2. Animal restrained with projector applied to the shoulder 38 Figure 3* The lateral movement of the head denoting a pain reaction 38 Figure 4. The experimental animal in the Euthanair with the projector applied to the skin of the shoulder 42 Figure 5» Electrical tooth stimulator (Painometer) 45 Figure 6. Electrical Design of the Electrical Tooth Stimulator 47 Figure 7* Painometer assembled with dog restrained 49 Figure 8. Exposure of operative field 55 Figure 9« Skin incision exposing cervical muscles 55 Figure 10. Exposure of the first and second cervical vertebrae 58 Figure 11. Removal of spine of axis 58 Figure 12. Removal of laminae of atlas 60 Figure 13. Insertion of the groove director into a small opening in the dura mater 60 Figure 14. Severing the dentate ligament 63 Figure 15* Sectioning the right lateral spinothalamic tract 63 Figure 16. Suturing the dura edges into apposition 65 Figure 17. Severing the first cervical nerve as it emerges from intervertebral foramen 65 1 INTRODUCTION The destruction of animals, whether the object in view be due to the advancing age or the prevention of further suf­ fering caused by disease or accident, is an operation which is repugnant to the operator and essential in the public in­ terest. It is not to be denied that when the time arrives that pets need to be put painlessly out of existence, they are entitled to receive in this last humane service the same high standard of care and attention which they generally re­ ceive during life. The views on which is the most humane method of euthanasia are extremely varied. Decompression is a method of euthanasia which simulates high altitude conditions and produces a decrease in oxygen tension and a state of anoxia. Cerebral anoxemia results in unconsciousness and death of the animal. The decompression of small animals as a method of euthanasia has found extensive use in certain areas of the United States. The Humane Society of Los Angeles, Calif., destroys approximately fifty dogs a day by decompression. This method of euthanasia is now in use in New York City, N. Y.; Chicago, 111.; San Francisco, Calif.; Brentwood, Mo.; Fort Wayne, Ind.; Bakersfield, Calif.; Los Angeles, Calif.; Tacooa, Wash.; Denver, Colo.; Palo Alta, Calif.; Santa Rosa, Calif.; and Pomona, Calif. Many other cities are contemplating its use. Workers using the Enthan- air, decompression system of euthanasia, feel that it has the 2 advantages of being cleaner, safer, not dangerous to the per­ sonnel, more humane than other methods of euthanasia, and requires less skill to operate. The originators1 of high altitude euthanasia for small animals installed a decompression apparatus (Euthanair) in the Veterinary Physiology and Pharmacology Department at Iowa State College in the spring of 1955 for purposes of experi­ mental research. Since several humane societies use this method of euthanasia, it would seem of widespread interest to know if pain is experienced during decompression. To ac­ curately obtain this information it is essential to determine the pain reaction threshold in an experimental animal. The pain reaction threshold is defined as the least amount of a quantitatively measurable stimulus necessary to evoke a pain reaction. A literature survey reveals a paucity of research on pain reaction thresholds in the animal and nearly its complete absence with the canine as the experimental subject. The purpose of this preliminary investigation was to deter­ mine if pain is perceived during decompression. Various methods of determining pain reaction thresholds in the dog were inves­ tigated. A surgical experiment was designed to completely alleviate the sensation of pain by the animal except froa ^Euthanair Engineering and Sales Company, 5156 Soutbridge Avenue, Los Angeles 43, California. 3 those structures supplied by certain cranial nerves. The amount of anxiety and apprehension during decompression was observed before and after the surgical operation. The effect of morphine on the pain reaction thresholds was recorded. Observations on the excitement and anxiety observed during decompression were recorded before and after morphine ad­ ministration to the dog. Movies were taken during decompres­ sion of the experimental animals for detailed study. 4 LITERATURE CITED Research by Woollard et al.