- Email: [email protected]
Factors influencing outcome in stab wounds of the heart
Factors Influencing Outcome Stab Wounds of the Heart
in
Carlos Arreola-Risa, MD, Peter Rhee, MD, Edward M. Boyle, MD, Ronald V. Maier, MD, Gregory G. Jurkovich, MD, Hugh M. Foy, MD, Seattle, .Washington BACKGROUND: The purpose of&is study WZIS to identify factors associated with unfavorable outcome following stab wounds to the heart in order to improve selection of patients who may benefit from aggressive resuscitative efforts. METHODS: Preoperative and operative variables were reviewed for all patients treated for cardiac stab wounds at a level I trauma center from 1987 to 1993 in an attempt to identify factors influencing survival. RESULTS: Twenty-nine (53%) of the 55 patients who were resuscitated following stab wounds to the heart during the study period survived. Although profound hypotension (systolic blood pressure ~40 mm Hg), cardiopuhnonary resuscitation, and emergency room thoracotomies were associated with poor outcome, none were uniformly predictive of death. Some patients survived with each of these characteristics. CONCLUSIONS: We recommend that all patients suspected of having cardiac stab wounds be fully resuscitated and undergo thoracotomy, as significant survival can be achieved and death is not always the outcome.
and servesWashingtonState, Alaska, Idaho, and Montana. HMC admitsapproximately 3,000 trauma casesannually. A chief resident or fellow provides in-house coverage aroundthe clock with an attendingphysician available on call for backup at all times. We identified the medical recordsof patientsadmitted to HMC with cardiac injuries resulting from stab wounds in the years 1987 to 1993. Patients with penetrating stab wounds to the heart were identified by International CZass$kationof Disease,9th Clinical Modification (ZCD9-CM) coding through medicalrecordsor by diagnosisoli our institutional trauma registry. In addition, files of the King County Medical Examiner’s office were utilized for patients who spentbut a brief period of time in our facility before being pronounceddead. All study patientshad manifestedat leastone signof life, either in the field or the emergency room (ER). Signs of life included a pulse,measurableblood pressure,or an organized cardiac rhythm. The patients were met in a dedicatedtrauma resuscitationroom where initial resuscitation efforts were undertaken following the American College of SurgeonsAdvanced Trauma Life Support protocols.13 Patients who were in extremis with penetrating chest trauma and who lost their vital signsin transport or in the resuscitationroom underwent emergency room thoracotomy (ERT). Patients who survived ERT, and other patients in more stable condition, were taken to the operating room for a definitive procedure.The vast majority of operationswere performed by trauma-trainedgeneralsurgeonswithout cardiopulmonary bypass. We abstractedfrom the records: patient demographics, mechanismof injury, prehospital,resuscitation,field and hospitalphysiologic parameters,nature of associatedinjuries,procedures,operativefindings, andoutcomes.Our institutional internal review board approvedthe study protocol. All statistical analyseswere performed using a statistical software packagefor personalcomputers(SPSS Windows version 6.0, SPSS,Inc., Chicago, Illinois). Relative risk (RR), independent t-tests, and chi-square analysis were usedto signify differences. P co.05 was considered significant.
tab woundsto the heart representa significant surgical challenge becauseof their unpredictableclinical course, the needfor emergencyclinical care (often including emergency room resuscitativethoracotomy), and the high risk that medical personnel will be exposed to blood-borne pathogens.While somepatients survive this dramatic injury and resuscitation,many succumbregardlessof the energy and resourcesexpended in attempts to save them. Reported mortality rates range from 10% to 70%, reflecting a variety of presentations,injury mechanisms,and prehospitalcare capabilities.l-l* The literature is not consistent as to what distinguishesa salvageablepatient from one in whom heroic care is futile.‘-‘* Theseconcernspromptedus to review our institutional experience with cardiac stab woundsin an attemptto identify factors predictive of death or disabling neurologic outcome. Our goal was to be able to rapidly identify patients in whom the massiveexpenditures of energy and resourcesinvolved in resuscitation RESULTS might be expectedto have the highestlikelihood of success. Our review found 55 patients with cardiac injuries from stabwounds in the 7-year period of the study, an average METHODS of 8 cardiac stab wounds per year. The total number of Harborview Medical Center (HMC) is a level I trauma trauma admissionsduring this period was 20,1!31, an incenter that is affiliated with the University of Washington cidence of 2.8 stab wounds to the heart per 1,000 trauma admissions. From the Department of Surgery, Harborview Medical Center, UniVictims of cardiac stabwounds had a meanage of 31.4 versity of Washington, Seattle, Washington. years. Eighty-four percentwere men. Black race was overRequests for reprints should be addressed to Hugh Foy, MD, Harborview representedin this population, as 36% of our study paMedical Center, 325 Ninth Ave, ZA-16, Seattle, Washington 98104. tients, but only 8% of our local Seattle population fit this Presented at the 81st Annual Meeting of the North Pacific Surgical demographiccategory. However, this figure is in close apAssociation, Coeur d’ Alene, Idaho, November 10-l 1, 1994.
S
THE AMERICAN
JOUkNAL
OF SURGERY”
VOLUME
169
MAY
1995
553
COMMENTS
TABLE Prehospital
Variables Survivors
~nsu~vars
Patients (n = 55) Blood pressure
29 (53%)
26 (47%)
~40‘ (n = 24)90 (t-l= 10)
4 (17%) 20 (44%) 9 (90%) 4 (17%) 19 (46%) 11(37%) 24 (63%)
20 (83%) 25 156%) 1 (10%) 20 (83%) 22 (54%) 19 (64%) 14 (37%)
CPR’ (n = 24) Associated
injuries
ER thoracotomies’ Tamponade’
(n = 41) (n = 30)
(t-i = 38)
‘Relative risk of death CPR = cardiopulmona~ fidence interval.
(95% a); P ~0.05, b&ailed t-test. resuscit~ion: ER = emer~ancy room; Cl = con-
proximation with the ethnic composition of our immediate, central Seattle neighborhood. Forty-five of the 55 patientswere testedfor the presence of alcohol; 37 (82%) of the 45 testedwere legally intoxicated, with an averageblood ethanol level of 218 mg/dL. Twenty-eight patients were suspectedof having taken illicit drugs, of whom 22 were positive when tested. Thus, the incidenceof illicit drug positivity amongthe entire series of 55 patientswas 40%. The overall survival rate was 53%, of whom 93% had normal neurologic outcome. Hypotension was a common presentation, with 45 (82%) of the 55 patients having a field blood pressure~90 mm Hg. Hypotension alone did not predict poor outcome, as 20 (44%) of our 45 hypotensive patients survived. Presentationin extremis was alsocommon. Twenty-four patients (44%) received cardiopulmonary resuscitation (CPR) in the field. Although CPR was a statistically significant predictor of mortality (RR 4.3), 4 patients (17%) who required CPR went on to survive. Many patients remained unstable. Thirty (55%) underwent ER thoracotomy, of whom 11 (37%) survived the procedure. Tamponade, confirmed by thoracotomy, occurred in 38 patients (69%) and had a protective predictive value. Patients with tamponadehad a statistically significant RR of 0.5. Twenty-four of the 29 survivors (83%) had evidence of tamponade. Associated injuries were defined as major visceral injuries. Lesssevere soft-tissue injuries were not analyzed. They were seenin 41 patients (75%). They had minimal effect on survival, as 19 (46%) of thoseaffected survived (Table). Injuries to the right ventricle were mostcommon (52%}, followed by left ventricle (30%), right atrium (12%), left atrium (3%), aorta (IS%), and coronary artery (1.5%). Single-chamber injuries (41) were more common than multiple-chamber injuries (11). The number of chambers injured in an individual was predictive of outcome. Multiple-chamber injury had an RR of 2.5 as opposedto single-chamber injuries, which had an RR of 0.4. Left ventricular injury was associatedwith death in 16 (80%) of 20 cases,and was predictive of death with an RR of 2.8 (P <0.05). 554
THE AMERICAN
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Faced with the rising incidence of interpersonal violence and the sky-rocketing cost of health care, we reviewed our experience with stabwounds to the heart. We were also concerned about the risk of exposure to potentially lethal blood-borne disease,which was underscoredby the 40% incidence of illicit drug use detected in our study population. We hy~thesized that certain preoperative casecharacteristics might indicate uniformly lethal outcome.This assumption was largely basedon our limited, anecdotalexperiencederived from encounteringslightly more than one penetratingcardiac injury (staband gunshot)per month in our institution. By identifying unsalvageablepatients, we hoped to decreasethe expenseand effort of futile medical care and di~nish exposureto blood-borne diseasesin the semicontrolledenvironment of ERT. The mortality ratein our 55patient study group was47%, representingthe middle ground in cardiac stab wound series, which have reported 8.5% to 68%.‘,4-‘2J4-20 The majority of our patientswere ~anspo~edby the Seattle Fire Department Paramedicprogram. Most were injured in the immediatecentral Seattle neighborhood,so that scene-tohospital transport time averagedonly 15.2 minutes. Most patients were in critical condition on arrival at the ER. CPR in the field wasrecorded in 24 (44%). CPR was a statistically significant predictor of mortality; patients undergoing CPR in the field were 4.3 times more Iikely to die than the rest. Nonetheless,4 patientswho required CPR in the field survived their injuries. Hypotension (blood pressure~90 mm Hg) was present in 82% of patients, but was also not uniformly predictive of death, as 44% of the hypotensive patients survived. Over half of our patientswere ill enough to require ERT, but one third of them survived. The only preoperativefactors that significantly predicted a lethal outcome were profound hypotension and the application of CPR in the field. Neither was 100% predictive. Other factors recognized only after thoracotomy-ie, left ventricular and multiple-chamber injury-were also predictive of mortality. Interestingly, in cuntrast to our experiencewith gunshotwounds, the presenceof visceral injury was not associatedwith increasedmortality.2’ Tamponade,usually consideredto be a premorbid condition and uniformly lethal if untreated, had a lower than expected RR. ashasalso been the casein other studiesi Tamponadewas noted frequently in our patients, and 63% of the patients who developed it survived. As hasbeenpointed out by Symbasz2and others,cardiac tamponade following cardiac injury is a dynamic phenomenonwith variable presentingsigns.Dependingon the she and location of both the chamberinjury and the pericardial defect, blood may either accumulatein the pericardium or drain into the pleural cavity. Often both processesoccur at variable and unpredictableintervals. The resultant clinical course may fluctuate, with alternating signsof Beck’s classictriad or hypovolemic shock.17*2z The high survival rate of our patientswith tamponadesuggests that patientswho exhibited signsof tamponadehad not yet bled to irreversible hypovolemic shock. Simply stated, tamponaderepresentsan immediately treatable mechaniMAY
1995
STAB WOUNDS TO THE HEAB’IYABREOLA-RISA cal problem that corrects promptly with pericardiotomy if volume status can be restored before the patient deteriorates to a state of irreversible metabolic derangement. Our study, despite being one of the larger investigations into outcome from a single type of cardiac injury, still suffers from relatively small numbers of patients and the inherent limitations of a purely retrospective review. In regard to our hypothesis, it is a “negative” study, inasmuch as unfortunately no single preoperative factor was indicative of uniform mortality. A more detailed statistical examination utilizing multiple regression analysis to examine the abilities of various combinations of factors to predict mortality might prove more helpful in this respect, but would require a much larger study population. Retrospective studies traditionally serve as internal quality assurance measures of institutional performance to compare with other published data. Unfortunately, few reports contain sufficient detail necessary for such comparisons. Ivatury and colleaguesz3 calculated the “Penetrating Cardiac Trauma Index” and measured the “Physiologic Index” in a landmark study proposing a systematic categorization of cardiac trauma to facilitate such interinstitutional comparisons. Such a system is unfortunately impractical for the trauma surgeon, since it is often a senior resident who is responsible for deciding who should or should not undergo ERT. As our study emphasizes, the system also contains the obvious limitation of requiring a thoracotomy to completely assess the extent of injury. A brief review of mortality statistics disproves the common misconception that increased survival has resulted from improvement in our prehospital systems of care.16 Notably, our mortality of 47% is at best midrange, but similar to rates reported by Denver General Hospital, whose staffing as a teaching hospital with well-organized prehospital careis very similar to our own.5v6l1oIn stark contrast, several international series, where prehospital care and transport are rudimentary at best, report remarkably low hospital mortality-ranging from 12% to 46%-for penetrating cardiac wounds.1~9~14~‘7,20,24 Undeniably, many injured patients are saved by well-developed prehospital care systems, but this is difficult to prove in injuries such as penetrating trauma without a detailed analysis of all components of the patients’ care. Additionally, the total number of patients with a specific injury needs to be determined to help establish a given community’s incidence of such wounds, to serve as a denominator to assess whether patients are first seen by the emergency department of the hospital or the coroner’s office.11,17,25Only then can one institution compare its results with others’. Development of local, state, and national trauma registries wilI help. It is often argued that the practice of taking patients with .a greater degree of physiologic derangement to the hospital most expediently worsens survival statistics, since such transport is often followed, after considerable investment of resources, by the patient’s demise due to irreversible hemorrhagic shock. The supposition is made that in the absence of such a practice, these patients would have succumbed in the field as a result of their injuries, as they most likely do in less developed countries that report impressive survival statistics. THE
AMERICAN
ET AL
Unlike many other studies, this review examines stab wounds separately from gunshot wounds, as the latter mechanism has a markedly different pathophysiology and outcome. We had hoped to identify reliable predictors of uniform mortality that could be applied by the receiving surgeon in the ER to better utilize resources and prevent unnecessary procedures. Critical decision making with limited data is the hallmark of trauma surgery, and such well-defined guidelines would be useful. While we identified preoperative factors associated with an increased likelihood of death (CPR in the field, multiple-chamber injury) or survival (tamponade), we could not identify any single preoperative factor that ‘uniformly predicted mortality from stab wounds to the heart. In our institution, resuscitative thoracotomy for penetrating cardiac trauma will remain an important component of our emergency care protocols. Thoracotomy, whether done in the emergency room or the operating room, is necessary to completely assess the ultimate survivability of penetrating stab wounds to the heart.
REFERENCES 1. Demetiades D. Cardiac wounds, experiencewith 70 patients.Ann Surg.
1986;203:315-317.
2. Demetriades D, CharalambidesC, Sareli P, Pantanowitz D. Late sequelaeof penetratingcardiacinjuries. BrJSurg. 1990;77:8 13-814. 3. Gervin AS, Fischer Rp. The importance of prompt transport in salvageof patients with penetratingheart wounds. J Trauma. 1982; 22~l43-448. 4. Henderson VJ, Smith S, Fry WR, et al. Cardiac injuries: analysis of an unselected series of 251 cases. J Trauma. 1994;36:341-348.
5. Honigman B, Rohweder K, Moore EE, et al. Prehospitaladvanced trauma life support for penetrating cardiac wounds. Ann Emerg Med. 1990;19:1145-1150. 6. Honigman B, Lowenstein SR, Moore EE, et al. The role of the pneumatic antishock garment in penetrating cardiac wounds. JAMA. 1991;266:2398-2401. 7. Kaplan AJ, Norcross ED, Crawford FA. Predictors of mortality in penetrating cardiac injury. Am Surg. 1993:59:338-341. 8. Marshall WG, Bell JL, Kouchoukos NT. Penetrating cardiac trauma. J Trauma. 1984;24:147-149. 9. McFarlane M, Branday JM. Penetrating injuries of the heart. West Indian Med J. 1990;39:74-79. 10. Moreno C, Moore EE, Majure JA, Hopeman AR. Pericardial tamponade: a critical determinant for survival following penetrating cardiac wounds. J Trauma. 1986;26:821-825. 11. Naughton MJ, Brissie RM, Bessey PQ, et al. Demography of penetrating cardiac trauma. Ann Surg. 1988;209:67fX83. 12. Sugg WL, Rea WJ, Ecker RR, et al. Penetrating wounds of the heart: an analysis of 459 cases. J Thorac Cardiovusc Surg. 1968;56: 53 l-540. 13. Alexander RH, Proctor HJ, eds. Advanced Trauma Life Support. Chicago: American College of Surgeons: 1993. 14. Velmahos GC, Degiannis E, Souter I, Saadia R. Penetrating trauma to the heart: a relatively innocent injury. Surgery. 1994:115: 694697. 15. Mandal AK, Opamh SS. Unusually low mortality of penetrating wounds of the chest. J Thorac Cardiovasc Surg. 1989;97: 119-125. 16. Harman PK, Trinkle JK. Injury to the heart. In: Moore EE, Mattox KL, Feliciano DV, eds. Trauma. East Norwalk, Connecticut: Appleton & Lange; 1991. . 17. Demetriades D, VanDerVeen BW. Penetrating injuries of the heart: experience over two years in South Africa. J Trauma. 1983;23:1034-1041. 18. Blake DP, Gisbert VL, Ney AL, et al. Survival after emergency
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OF SURGERY”
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STAR WOUNDS
TO THE HEART/ARREOLA-RJSA
ET AL
department versus operating room thoracotomy for penetrating cardiac injuries. Am Surg. 1992;58:329-333. 19. Attar S, Suter CM, Hankins JR, et al. Penetrating cardiac injuries. Ann Thoruc Surg. 1991;51:711-716. 20. Benyan AK, Al-A’Ragy HH. The pattern of penetrating cardiac trauma in Basrah province: personal experience with seventy-two cases in a hospital without cardiopulmonary bypass facility. Znt Surg. 1992;77: 11 l-l 13. 21. Arreola-Risa C, Boyle EM, Foy HF, et al. Gunshot wounds of the heart: factors influencing outcome. Chest. 1994;106:41. 22. Symbas PN. Curdiothoracic Trauma. Philadelphia: W.B. Saunders; 1989:404.
556
23. Ivatnry RR, Nallathambi MN, Stahl WM, Rohman M. Penetrating cardiac trauma, quantifying the severity of anatomic and physiologic injury. Ann Surg. 1987;205:6166. 24. Catipovic-Veselica K, Sincic V, Durijancek J, et al. Penetrating heart wounds repaired without cardiopulmonary bypass: evaluation and follow-up of recent war injuries. Tex Heart Znst .I. 1993;20: 94-98. 25. Okada
Y, Suzuki H, Mukaida M, Ishiyama 1. Penetrating cardiac injuries: a pathological analysis of 20 autopsy cases.Am J Forensic Med Pathol. 1990;11:144-148.
THE AMERICAN JOURNAL OF SURGERY” VOLUME 169 MAY 1995
in
Carlos Arreola-Risa, MD, Peter Rhee, MD, Edward M. Boyle, MD, Ronald V. Maier, MD, Gregory G. Jurkovich, MD, Hugh M. Foy, MD, Seattle, .Washington BACKGROUND: The purpose of&is study WZIS to identify factors associated with unfavorable outcome following stab wounds to the heart in order to improve selection of patients who may benefit from aggressive resuscitative efforts. METHODS: Preoperative and operative variables were reviewed for all patients treated for cardiac stab wounds at a level I trauma center from 1987 to 1993 in an attempt to identify factors influencing survival. RESULTS: Twenty-nine (53%) of the 55 patients who were resuscitated following stab wounds to the heart during the study period survived. Although profound hypotension (systolic blood pressure ~40 mm Hg), cardiopuhnonary resuscitation, and emergency room thoracotomies were associated with poor outcome, none were uniformly predictive of death. Some patients survived with each of these characteristics. CONCLUSIONS: We recommend that all patients suspected of having cardiac stab wounds be fully resuscitated and undergo thoracotomy, as significant survival can be achieved and death is not always the outcome.
and servesWashingtonState, Alaska, Idaho, and Montana. HMC admitsapproximately 3,000 trauma casesannually. A chief resident or fellow provides in-house coverage aroundthe clock with an attendingphysician available on call for backup at all times. We identified the medical recordsof patientsadmitted to HMC with cardiac injuries resulting from stab wounds in the years 1987 to 1993. Patients with penetrating stab wounds to the heart were identified by International CZass$kationof Disease,9th Clinical Modification (ZCD9-CM) coding through medicalrecordsor by diagnosisoli our institutional trauma registry. In addition, files of the King County Medical Examiner’s office were utilized for patients who spentbut a brief period of time in our facility before being pronounceddead. All study patientshad manifestedat leastone signof life, either in the field or the emergency room (ER). Signs of life included a pulse,measurableblood pressure,or an organized cardiac rhythm. The patients were met in a dedicatedtrauma resuscitationroom where initial resuscitation efforts were undertaken following the American College of SurgeonsAdvanced Trauma Life Support protocols.13 Patients who were in extremis with penetrating chest trauma and who lost their vital signsin transport or in the resuscitationroom underwent emergency room thoracotomy (ERT). Patients who survived ERT, and other patients in more stable condition, were taken to the operating room for a definitive procedure.The vast majority of operationswere performed by trauma-trainedgeneralsurgeonswithout cardiopulmonary bypass. We abstractedfrom the records: patient demographics, mechanismof injury, prehospital,resuscitation,field and hospitalphysiologic parameters,nature of associatedinjuries,procedures,operativefindings, andoutcomes.Our institutional internal review board approvedthe study protocol. All statistical analyseswere performed using a statistical software packagefor personalcomputers(SPSS Windows version 6.0, SPSS,Inc., Chicago, Illinois). Relative risk (RR), independent t-tests, and chi-square analysis were usedto signify differences. P co.05 was considered significant.
tab woundsto the heart representa significant surgical challenge becauseof their unpredictableclinical course, the needfor emergencyclinical care (often including emergency room resuscitativethoracotomy), and the high risk that medical personnel will be exposed to blood-borne pathogens.While somepatients survive this dramatic injury and resuscitation,many succumbregardlessof the energy and resourcesexpended in attempts to save them. Reported mortality rates range from 10% to 70%, reflecting a variety of presentations,injury mechanisms,and prehospitalcare capabilities.l-l* The literature is not consistent as to what distinguishesa salvageablepatient from one in whom heroic care is futile.‘-‘* Theseconcernspromptedus to review our institutional experience with cardiac stab woundsin an attemptto identify factors predictive of death or disabling neurologic outcome. Our goal was to be able to rapidly identify patients in whom the massiveexpenditures of energy and resourcesinvolved in resuscitation RESULTS might be expectedto have the highestlikelihood of success. Our review found 55 patients with cardiac injuries from stabwounds in the 7-year period of the study, an average METHODS of 8 cardiac stab wounds per year. The total number of Harborview Medical Center (HMC) is a level I trauma trauma admissionsduring this period was 20,1!31, an incenter that is affiliated with the University of Washington cidence of 2.8 stab wounds to the heart per 1,000 trauma admissions. From the Department of Surgery, Harborview Medical Center, UniVictims of cardiac stabwounds had a meanage of 31.4 versity of Washington, Seattle, Washington. years. Eighty-four percentwere men. Black race was overRequests for reprints should be addressed to Hugh Foy, MD, Harborview representedin this population, as 36% of our study paMedical Center, 325 Ninth Ave, ZA-16, Seattle, Washington 98104. tients, but only 8% of our local Seattle population fit this Presented at the 81st Annual Meeting of the North Pacific Surgical demographiccategory. However, this figure is in close apAssociation, Coeur d’ Alene, Idaho, November 10-l 1, 1994.
S
THE AMERICAN
JOUkNAL
OF SURGERY”
VOLUME
169
MAY
1995
553
COMMENTS
TABLE Prehospital
Variables Survivors
~nsu~vars
Patients (n = 55) Blood pressure
29 (53%)
26 (47%)
~40‘ (n = 24)
4 (17%) 20 (44%) 9 (90%) 4 (17%) 19 (46%) 11(37%) 24 (63%)
20 (83%) 25 156%) 1 (10%) 20 (83%) 22 (54%) 19 (64%) 14 (37%)
CPR’ (n = 24) Associated
injuries
ER thoracotomies’ Tamponade’
(n = 41) (n = 30)
(t-i = 38)
‘Relative risk of death CPR = cardiopulmona~ fidence interval.
(95% a); P ~0.05, b&ailed t-test. resuscit~ion: ER = emer~ancy room; Cl = con-
proximation with the ethnic composition of our immediate, central Seattle neighborhood. Forty-five of the 55 patientswere testedfor the presence of alcohol; 37 (82%) of the 45 testedwere legally intoxicated, with an averageblood ethanol level of 218 mg/dL. Twenty-eight patients were suspectedof having taken illicit drugs, of whom 22 were positive when tested. Thus, the incidenceof illicit drug positivity amongthe entire series of 55 patientswas 40%. The overall survival rate was 53%, of whom 93% had normal neurologic outcome. Hypotension was a common presentation, with 45 (82%) of the 55 patients having a field blood pressure~90 mm Hg. Hypotension alone did not predict poor outcome, as 20 (44%) of our 45 hypotensive patients survived. Presentationin extremis was alsocommon. Twenty-four patients (44%) received cardiopulmonary resuscitation (CPR) in the field. Although CPR was a statistically significant predictor of mortality (RR 4.3), 4 patients (17%) who required CPR went on to survive. Many patients remained unstable. Thirty (55%) underwent ER thoracotomy, of whom 11 (37%) survived the procedure. Tamponade, confirmed by thoracotomy, occurred in 38 patients (69%) and had a protective predictive value. Patients with tamponadehad a statistically significant RR of 0.5. Twenty-four of the 29 survivors (83%) had evidence of tamponade. Associated injuries were defined as major visceral injuries. Lesssevere soft-tissue injuries were not analyzed. They were seenin 41 patients (75%). They had minimal effect on survival, as 19 (46%) of thoseaffected survived (Table). Injuries to the right ventricle were mostcommon (52%}, followed by left ventricle (30%), right atrium (12%), left atrium (3%), aorta (IS%), and coronary artery (1.5%). Single-chamber injuries (41) were more common than multiple-chamber injuries (11). The number of chambers injured in an individual was predictive of outcome. Multiple-chamber injury had an RR of 2.5 as opposedto single-chamber injuries, which had an RR of 0.4. Left ventricular injury was associatedwith death in 16 (80%) of 20 cases,and was predictive of death with an RR of 2.8 (P <0.05). 554
THE AMERICAN
JOURNAL
OF SURGERP
VOLUME
169
Faced with the rising incidence of interpersonal violence and the sky-rocketing cost of health care, we reviewed our experience with stabwounds to the heart. We were also concerned about the risk of exposure to potentially lethal blood-borne disease,which was underscoredby the 40% incidence of illicit drug use detected in our study population. We hy~thesized that certain preoperative casecharacteristics might indicate uniformly lethal outcome.This assumption was largely basedon our limited, anecdotalexperiencederived from encounteringslightly more than one penetratingcardiac injury (staband gunshot)per month in our institution. By identifying unsalvageablepatients, we hoped to decreasethe expenseand effort of futile medical care and di~nish exposureto blood-borne diseasesin the semicontrolledenvironment of ERT. The mortality ratein our 55patient study group was47%, representingthe middle ground in cardiac stab wound series, which have reported 8.5% to 68%.‘,4-‘2J4-20 The majority of our patientswere ~anspo~edby the Seattle Fire Department Paramedicprogram. Most were injured in the immediatecentral Seattle neighborhood,so that scene-tohospital transport time averagedonly 15.2 minutes. Most patients were in critical condition on arrival at the ER. CPR in the field wasrecorded in 24 (44%). CPR was a statistically significant predictor of mortality; patients undergoing CPR in the field were 4.3 times more Iikely to die than the rest. Nonetheless,4 patientswho required CPR in the field survived their injuries. Hypotension (blood pressure~90 mm Hg) was present in 82% of patients, but was also not uniformly predictive of death, as 44% of the hypotensive patients survived. Over half of our patientswere ill enough to require ERT, but one third of them survived. The only preoperativefactors that significantly predicted a lethal outcome were profound hypotension and the application of CPR in the field. Neither was 100% predictive. Other factors recognized only after thoracotomy-ie, left ventricular and multiple-chamber injury-were also predictive of mortality. Interestingly, in cuntrast to our experiencewith gunshotwounds, the presenceof visceral injury was not associatedwith increasedmortality.2’ Tamponade,usually consideredto be a premorbid condition and uniformly lethal if untreated, had a lower than expected RR. ashasalso been the casein other studiesi Tamponadewas noted frequently in our patients, and 63% of the patients who developed it survived. As hasbeenpointed out by Symbasz2and others,cardiac tamponade following cardiac injury is a dynamic phenomenonwith variable presentingsigns.Dependingon the she and location of both the chamberinjury and the pericardial defect, blood may either accumulatein the pericardium or drain into the pleural cavity. Often both processesoccur at variable and unpredictableintervals. The resultant clinical course may fluctuate, with alternating signsof Beck’s classictriad or hypovolemic shock.17*2z The high survival rate of our patientswith tamponadesuggests that patientswho exhibited signsof tamponadehad not yet bled to irreversible hypovolemic shock. Simply stated, tamponaderepresentsan immediately treatable mechaniMAY
1995
STAB WOUNDS TO THE HEAB’IYABREOLA-RISA cal problem that corrects promptly with pericardiotomy if volume status can be restored before the patient deteriorates to a state of irreversible metabolic derangement. Our study, despite being one of the larger investigations into outcome from a single type of cardiac injury, still suffers from relatively small numbers of patients and the inherent limitations of a purely retrospective review. In regard to our hypothesis, it is a “negative” study, inasmuch as unfortunately no single preoperative factor was indicative of uniform mortality. A more detailed statistical examination utilizing multiple regression analysis to examine the abilities of various combinations of factors to predict mortality might prove more helpful in this respect, but would require a much larger study population. Retrospective studies traditionally serve as internal quality assurance measures of institutional performance to compare with other published data. Unfortunately, few reports contain sufficient detail necessary for such comparisons. Ivatury and colleaguesz3 calculated the “Penetrating Cardiac Trauma Index” and measured the “Physiologic Index” in a landmark study proposing a systematic categorization of cardiac trauma to facilitate such interinstitutional comparisons. Such a system is unfortunately impractical for the trauma surgeon, since it is often a senior resident who is responsible for deciding who should or should not undergo ERT. As our study emphasizes, the system also contains the obvious limitation of requiring a thoracotomy to completely assess the extent of injury. A brief review of mortality statistics disproves the common misconception that increased survival has resulted from improvement in our prehospital systems of care.16 Notably, our mortality of 47% is at best midrange, but similar to rates reported by Denver General Hospital, whose staffing as a teaching hospital with well-organized prehospital careis very similar to our own.5v6l1oIn stark contrast, several international series, where prehospital care and transport are rudimentary at best, report remarkably low hospital mortality-ranging from 12% to 46%-for penetrating cardiac wounds.1~9~14~‘7,20,24 Undeniably, many injured patients are saved by well-developed prehospital care systems, but this is difficult to prove in injuries such as penetrating trauma without a detailed analysis of all components of the patients’ care. Additionally, the total number of patients with a specific injury needs to be determined to help establish a given community’s incidence of such wounds, to serve as a denominator to assess whether patients are first seen by the emergency department of the hospital or the coroner’s office.11,17,25Only then can one institution compare its results with others’. Development of local, state, and national trauma registries wilI help. It is often argued that the practice of taking patients with .a greater degree of physiologic derangement to the hospital most expediently worsens survival statistics, since such transport is often followed, after considerable investment of resources, by the patient’s demise due to irreversible hemorrhagic shock. The supposition is made that in the absence of such a practice, these patients would have succumbed in the field as a result of their injuries, as they most likely do in less developed countries that report impressive survival statistics. THE
AMERICAN
ET AL
Unlike many other studies, this review examines stab wounds separately from gunshot wounds, as the latter mechanism has a markedly different pathophysiology and outcome. We had hoped to identify reliable predictors of uniform mortality that could be applied by the receiving surgeon in the ER to better utilize resources and prevent unnecessary procedures. Critical decision making with limited data is the hallmark of trauma surgery, and such well-defined guidelines would be useful. While we identified preoperative factors associated with an increased likelihood of death (CPR in the field, multiple-chamber injury) or survival (tamponade), we could not identify any single preoperative factor that ‘uniformly predicted mortality from stab wounds to the heart. In our institution, resuscitative thoracotomy for penetrating cardiac trauma will remain an important component of our emergency care protocols. Thoracotomy, whether done in the emergency room or the operating room, is necessary to completely assess the ultimate survivability of penetrating stab wounds to the heart.
REFERENCES 1. Demetiades D. Cardiac wounds, experiencewith 70 patients.Ann Surg.
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