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ACADEMIC EMERGENCY MEDICINE • March 2001, Volume 8, Number 3 299
CORRESPONDENCEPATCH4 the Flowing DAM
Resuscitation attempts for patientsin pulseless electrical activity (PEA)frequently fail.1 Among other rea-sons for the poor success rate is de-layed diagnosis because resuscita-tors may forget to consider some ofthe many etiologies of PEA.
I offer a mnemonic that synthe-sizes 12 categories of PEA, and mayalso be used for patients with hypo-tension with a concomitant appro-priate sinus tachycardia.
PATCH4 the Flowing DAM
P = Pulmonary embolism; A = Aci-dosis/Alkalosis; T = Tension pneu-mothorax; C = Cardiac mechanicalinjury, such as tamponade, valve, orseptal ruptures; H4 = 4 Hs, Hypo-thermia, Hypokalemia, Hypoxemia,and Hyperkalemia.
Flowing = reminds one of a bloodvessel and the four major problemsthat can cause low pressure: 1) poorvascular tone (e.g., anaphylaxis, sep-sis, Addisonian crisis, or neurogenicshock); 2) leaky vessels (e.g., sepsisor sequestration into an inflamed or-gan); 3) empty vessels due to highoutput (bleed, diarrhea, diuresis);and 4) empty vessels due to low in-put (dehydration).D = Drugs, including those that af-
fect vascular tone such as benzodi-azepines or opioids, those causing anextension of therapeutic effects (e.g.,antihypertensives), and drug over-doses; A = Aortic aneurysm rupture;M = Myocardial infarction.
The ‘‘4’’ is pronounced ‘‘for’’ soone can visualize the resuscitationas a ‘‘patch’’ for a breaking dam, i.e.,a major problem. Naturally, thismnemonic only provides a list of eti-ologies, and clinical judgment mustbe used when applying it to a givenpatient.
I have found the mnemonic veryhelpful when directing inpatient re-suscitations and hope that residents,ACLS students, and practitioners alsofind it useful.—RALPH LEONARD,MD ([email protected]),graduate student, Harvard School ofPublic Health, Boston, MA
Key words. mnemonic; resuscita-tion; pulseless electrical activity; di-agnosis.
Reference
1. Parish DC, Dane FC, Montgomery M,Wynn LJ, Durham MD, Brown TD. Re-suscitation in the hospital: relationshipof year and rhythm to outcome. Resus-citation. 2000; 47:219–29.
Bilevel Positive Airway Pressure forPresumed Pulmonary Edema
Craven et al.1 report that out-of-hos-pital personnel can be trained to de-liver noninvasive ventilation withbilevel positive airway pressure(BiPAP) to patients with presumedcongestive heart failure (CHF).While we applaud the effort to ex-pand new treatment modalities intothe out-of-hospital setting, we aretroubled by the choice of BiPAP forpresumed pulmonary edema.
Evidence from several random-ized controlled trials support the useof continuous positive airway pres-sure (CPAP) in patients with acute
cardiogenic pulmonary edema(ACPE) as a means of averting theneed for endotracheal intubationand potentially reducing mortality.2
There is no evidence that the use ofBiPAP confers any outcome benefitover CPAP in the context of ACPE.3
In fact, as the authors acknowledge,the use of BiPAP in this setting maybe associated with an increased rateof myocardial infarction anddeath.4,5 In light of this, it is con-cerning that the authors found anin-hospital mortality rate for pa-tients treated in the field with
BiPAP nearly double that for controlpatients.
Finally, we find it remarkablethat ‘‘discharge diagnoses confirmedthe presence of CHF in all pa-tients . . . included in the analysis.’’Previous studies have found para-medics to be between 70% and 88%accurate in the diagnosis of ACPE.6–8
It is unclear to us whether the onepatient who ‘‘had asthma ratherthan CHF’’ was withdrawn from thestudy at the outset or only in retro-spect, when the alternative diagno-sis was made. In the latter case, thepatient should have been included inthe analysis.—JOSHUA M. KO-SOWSKY, MD, and RICHARD ZANE,MD, Department of Emergency Med-icine, Brigham and Women’s Hospi-tal, Boston, MA
Key words. bilevel positive airwaypressure; out-of-hospital training;ventilation; congestive heart failure;pulmonary edema; continuous posi-tive airway pressure.
References
1. Craven RA, Singletary N, Bosken L,Sewell E, Payne M, Lipsey R. Use of bi-level positive airway pressure in out-of-hospital patients. Acad Emerg Med.2000; 7:1065–8.2. Pang D, Keenan SP, Cook DJ, et al.The effect of positive pressure airwaysupport on mortality and the need for in-tubation in cardiogenic pulmonaryedema. Chest. 1998; 114:1185–92.3. Kosowsky JM, Storrow AB, CarletonSC. Continuous and bi-level positive air-way pressure in the treatment of acutecardiogenic pulmonary edema. Am JEmerg Med. 2000; 18:91–5.4. Mehta S, Jay GD, Woolard RH, et al.Randomized, prospective trial of bilevelvs continuous positive airway pressurein acute pulmonary edema. Crit CareMed. 1997; 25:620–8.5. Wood KA, Lewis L, Von Harz B, et al.The use of noninvasive positive pressureventilation in the emergency depart-ment: results of a randomized clinicaltrial. Chest. 1998; 113:1339–46.6. Tresch DD, Dabrowski RC, FiorettiGP, Darin JC, Brooks HL. Out-of-hospi-tal pulmonary edema: diagnosis andtreatment. Ann Emerg Med. 1983; 12:533–7.7. Hoffman JR, Reynolds S. Comparisonof nitroglycerin, morphine and furose-mide in treatment of presumed pre-hos-pital pulmonary edema. Chest. 1987; 92:586–93.8. Wuerz RC, Meador SA. Effects of pre-hospital medications on mortality andlength of stay in congestive heart failure.Ann Emerg Med. 1992; 21:669–74.
