My patient with diverticular bleed has now developed signs of bowel ischemia with abdominal pain and sepsis after transcatheter colic artery embolization. Is bowel ischemia common after embolization of lower gastrointestinal (GI) arteries?

It may be more common than we think! Reported rates of bowel ischemia following lower GI artery embolization have been as high as 22% (1,2). For this reason, it is prudent to closely monitor for signs of bowel ischemia and infection in patients who undergo embolization to control lower GI bleeding.

In some cases, ischemia of the bowel appears to be mild enough to be treated conservatively, while in other cases bowel infarction with surgical intervention has been necessary (1).  One case report described signs of infection (including fever, abdominal tenderness and leukocytosis) 2 days after arterial embolization in a patient who was treated conservatively (3), while another described “sepsis” 6 days post procedure with bowel wall ischemia requiring surgical resection (1). 

Bowel injury leading to a septic picture following embolization of lower GI arteries should not be surprising given the expected capillary hypoperfusion and risk of tissue hypoxia.  Compared to embolization for upper GI bleed, lower GI embolization may place the patient at higher risk of bowel ischemia bowel ischemia due to lack of a rich collateral blood supply (1).  Older patients may also have mesenteric artery atherosclerotic disease or low cardiac output,  further compromising the collateral blood flow (3).  

At a more molecular level, hypoxia leads to the activation of hypoxia-inducible factor (HIF-1), which plays an important role in inducing gut injury. In fact, deletion of HIF-1a in mice prevented shock-induced intestinal permeability and bacterial translocation that ultimately led to bacteremia (4). 

As for preventing embolization-induced bacteremia, although antibiotics are used for liver and spleen embolization prophylaxis, their role in colic angioembolization is unclear (5).  

Bonus Pearl: Did you know that some of the earliest angioembolizations were performed during the Vietnam War to stop bleeding from bullet injuries? (6)

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References:

  1. Gady, J, Reynolds, H., & Blum, A. Selective arterial embolization for control of lower gastrointestinal bleeding: Recommendations for a clinical management pathway. Current Surg 2003; 60: 344-347. https://www.sciencedirect.com/science/article/abs/pii/S0149794402007493
  2. Rossetti A, Buchs NC, Breguet R, et al. Transarterial embolization in acute colonic bleeding: review of 11 years of experience and long-term results. Int J Colo Dis 2013;28:777-782. https://link.springer.com/article/10.1007/s00384-012-1621-5
  3. Shenoy, S, Satchidanand, S, & Wesp S. Colonic ischemic necrosis following therapeutic embolization. Gastrointest Radiol 1981, 6: 235-237. https://link.springer.com/article/10.1007/BF01890256
  4. Vollmar, B., & Menger, M. Intestinal ischemia/reperfusion: Microcirculatory pathology and functional consequences. Langenbeck Arch Surg 2011; 396: 13-29 https://link.springer.com/article/10.1007%2Fs00423-010-0727-x 
  5. Ryan, J. Mark, Ryan, Barbara M, & Smith, Tony P. Antibiotic prophylaxis in interventional radiology. JVIR 2004; 15: 547-556. https://www.sciencedirect.com/science/article/pii/S1051044307603248
  6. Nolan, T, Phan H, Hardy A, et al. Bullet embolization: Multidisciplinary approach by interventional radiology and surgery. Semin Interven Radiol 2012, 29: 192-6. https://www.ncbi.nlm.nih.gov/pubmed/23997411 

Contributed by Hannah Ananda Bougleux Gomes, Medical Student, Harvard Medical School, Boston, MA.

My patient with diverticular bleed has now developed signs of bowel ischemia with abdominal pain and sepsis after transcatheter colic artery embolization. Is bowel ischemia common after embolization of lower gastrointestinal (GI) arteries?

Is the average body temperature in adults lower than 98.6 ᵒF (37 ᵒC)?

Despite the widely-held belief that the normal body temperature is 98.6 ᵒF (37.0 ᵒC), it is becoming increasingly clear that the average body temperature among adults (at least in the U.S.) is actually lower than 98.6 ᵒF (37 ᵒC).

The concept of a single normal body temperature dates way back to the 1800’s, based on measuring axillary temperatures by mercury thermometers. 1 However, a 2001 systematic literature review of 20 studies (1935-1998) of normal body temperature measured in adults found the following mean temperatures: oral 97.5 ᵒF (36.4 ᵒC), rectal 98.4 ᵒF (36.9 ᵒC), tympanic 97.7 ᵒF (36.5 ᵒC), and axillary 97.3 ᵒF (36.3 ᵒC ).  A British study involving >35,000 patients also found a lower mean oral temperature of 97.9 ᵒF (36.6 ᵒC). 2 A 2020 US study of a cohort of >150,000 adults (2007-20017) found a mean oral temperature of 98.1 ᵒF (36.7 ᵒC) in men and 98.2 ᵒF (36.8 ᵒC) in women; these values were lower than that of an earlier cohort (1971-1975). 3

So is the discrepancy between the body temperature in 1800’s and the more recent era due to the differences in measurement techniques or the population? In other words, are we cooling off?

The weight of the evidence suggests that our bodies are cooling!3  The study of an 1860-1940 cohort—presumably using similar thermometer techniques —found a gradual drop in the mean temperature during that period alone. Since axillary temperature (accounting for some of the values in the earlier cohort) is about 1 ᵒC lower than that of oral temperature, the magnitude of the drop in mean temperatures over the past 150 years is likely higher that those reported. 3

Potential explanations for our cooling bodies over the past 2 centuries include reduction in the population level inflammation due to improved standard of living, sanitation, lower incidence of chronic infections. improved dental hygiene, and cooler ambient temperatures. 3

 

Fun Fact: Did you know that in 1851 Carl Wunderlich, a German physician, obtained millions of axillary temperatures from 25,000 patients in Leipzig and thereby established the standard body temperature of 98.6 ᵒF (37 ᵒC)? ᵒ

 

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References

  1. Sund-Levander M, Forsberg C, Wahren LK. Normal oral, rectal, tympanic and axillary body temperature in adult men and women: a systematic literature review. Scan J Caring Sci 2002;16:122-128. https://www.ncbi.nlm.nih.gov/pubmed/12000664
  2. Obermeyer Z, Samra JK, Mullainathan S. Individual differences in normal body temperature: longitudinal big data analysis of patient records. BMJ 2017;359:j5468. https://www.ncbi.nlm.nih.gov/pubmed/29237616
  3. Protsiv M, Ley C, Lankester J, et al. Decreasing human body temperature in the United States since the industrial revolution. Human Biology and Medicine, Jan 7, 2020. DOI: 10.7554/eLife.49555. https://www.researchgate.net/publication/338433061_Decreasing_human_body_temperature_in_the_United_States_since_the_industrial_revolution
Is the average body temperature in adults lower than 98.6 ᵒF (37 ᵒC)?

Why is my diabetic patient complaining of arm pain and localized edema for couple of weeks without an obvious cause?

Aside from the usual suspects associated with a painful extremity (eg, trauma, deep venous thrombosis and soft tissue infections), think of spontaneous diabetic myonecrosis (DMN), also known as diabetic muscle infarction (1-3).

DMN is characterized by abrupt onset of painful swelling of the affected muscle, most often of the lower extremities, but also occasionally upper extremities. DMN occurs in patients with longstanding DM whose blood glucose control has deteriorated over time, often with nephropathy, retinopathy and/or neuropathy (1-3).

Couple of things to remember when considering DMN in your differential of a painful extremity. First, except for localized edema and tenderness over the involved muscle, the exam may be unremarkable. Specifically, there is no erythema or signs of compartment syndrome and fever is absent in the great majority of patients (~90%) (2). Even white blood cell count and creatine kinase (CK) are usually normal. The reason for normal CK at presentation is not clear but CK might have already peaked by the time of patient presentation (3). In contrast, C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) are usually elevated (>80%) (1).

MRI (without contrast in patients with renal insufficiency) is the imaging of choice with muscle enlargement and edema with hyperintense signal on T2-weighted images and other changes, including perifascial, perimuscular and or subcutaneous edema (1-3). Muscle biopsy is not currently recommended because of its adverse impact on time to symptomatic improvement. Non-surgical therapy, with rest, analgesia and glycemic control is usually recommended (1-3).

 
Though its exact cause is still unclear, atherosclerosis, diabetic microangiopathy, vasculitis with thrombosis and ischemia-reperfusion injury have been posited as potential precipitants for DMN. The role of anti-phospholipid syndrome, particularly in patients with type I DM, is unclear (1,2).

 
Bonus pearl: Did you know that symptoms of DMN may last for weeks with at least one-third of patients having a recurrence in the same muscle or elsewhere (1)?

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Reference
1. Horton WB, Taylor JS, Ragland TJ, et al. Diabetic muscle infarction: a systematic review. BMJ Open Diabetes Research and Care 2015;3:e000082.
2. Trujillo-Santos AJ. Diabetic muscle infarction. An underdiagnosed complication of long-standing diabetes. Diabetes Care 2003;26:211-15.
3. Diabetes muscle infarction in end-stage renal disease:A scoping review on epidemiology, diagnosis and treatment. World J Nephrol 2018;7:58-64.

Why is my diabetic patient complaining of arm pain and localized edema for couple of weeks without an obvious cause?

My 70 year old male patient is admitted with 1 day of fever, dysuria, and urinary frequency and urgency, but has a negative urine dipstick test for nitrites and leukocyte esterase. Could he still have acute bacterial prostatitis?

Short answer: Yes! In fact, no routine clinical imaging test can adequately rule out prostatic involvement in men with urinary tract infection (UTI) symptoms (1)! 

Although the presence of nitrites and leukocyte esterase (LE) may have a high positive predictive value for acute bacterial prostatitis (ABP) (~95%), their combined absence has a negative predictive value of only ~70%; ie, we may miss about one-third of patients with UTI symptoms if we relied solely on the results of nitrite and LE urine dipstick (2,3). Negative nitrites alone has a negative predictive value of only ~ 45%, while a negative LE has a negative predictive value of ~60% (3).

To evaluate for ABP, our patient should undergo rectal exam for prostatic tenderness, as should all men with UTI symptoms. The finding of a tender prostate in this setting is supportive of ABP, although its absence will still not rule out this diagnosis because the reported sensitivity of rectal exam may vary from 9% to 100% in ABP (1). 
Although there may not be a general agreement on the definition of ABP, 2 studies utilizing indium-labeled leukocyte scintigraphy or a combination of PSA levels and transrectal ultrasound have provided evidence for frequent prostatic involvement in men with UTI symptoms (4,5).  In these studies, an inflammatory reaction within the prostate was seen in the majority of cases, even when the digital rectal examination was not painful or when clinicians diagnosed pyelonephritis without prostatitis.
Bonus pearl: Did you know that the lifetime probability of a man receiving a diagnosis of prostatitis is >25% (1)? 

Also see a related P4P pearl: https://pearls4peers.com/2017/07/27/should-male-patients-with-suspected-urinary-tract-infection-routinely-undergo-a-prostate-exam/

 

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References
1. Etienne M, Chavanet P, Sibert L, et al. Acute bacterial prostatitis: heterogeneity in diagnostic criteria and management. Retrospective multicentric analysis of 371 patients diagnosed with acute prostatitis. BMC Infect Dis 2008, 8:12 doi:10.1186/1471-2334-8-12. https://bmcinfectdis.biomedcentral.com/articles/10.1186/1471-2334-8-12
2. Lipsky BA, Byren I, Hoey CT. Treatment of bacterial prostatitis. Clin Infect Dis 2010;50:1641-1652. https://academic.oup.com/cid/article/50/12/1641/305217
3. Etienne M, Pestel-Caron M, Chavanet P, et al. Performance of the urine leukocyte esterase and nitrite dipstick test for the diagnosis of acute prostatitis. Clin Infect Dis 2008; 46:951-53. https://academic.oup.com/cid/article/46/6/951/351423
4. Velasco M, Mateos JJ, Martinez JA, et al. Accurate topographical diagnosis of urinary tract infection in male patients with (111)indium-labelled leukocyte scintigraphy. Eur J Intern Med 2004;15:157-61. https://www.ncbi.nlm.nih.gov/pubmed/15245717
5. Ulleryd P, Zackrisson B, Aus G, et al. Prostatic involvement in men with febrie urinary tract infection as measured by serum prostate-specific antigen and transrectal ultrasonography. BJU Int 1999;84:470-74. https://onlinelibrary.wiley.com/doi/full/10.1046/j.1464-410x.1999.00164.x

 

My 70 year old male patient is admitted with 1 day of fever, dysuria, and urinary frequency and urgency, but has a negative urine dipstick test for nitrites and leukocyte esterase. Could he still have acute bacterial prostatitis?

My postop patient now has fever with atelectasis on her chest X-ray one day after surgery. Does atelectasis cause fever?

Although fever and atelectasis often coexist during the early postop period, there is no evidence that atelectasis causes fever.

A 2011 systematic analysis of 8 published studies found that all but 1 study failed to find a significant association between postop fever and atelectasis.A 1988 study reported a significant association between postop fever during the first 48 h and atelectasis on day 4 postop, but not each postop day.2  Even in this study, however, fever as a predictor of atelectasis performed poorly with a sensitivity of 26%, specificity of 75% and accuracy of 43%.

In another study involving postop cardiac surgery patients, despite a fall in the incidence of fever from day 0 to day 2, the incidence of atelectasis based on serial chest X-rays actually  increased. 3

Experimental studies in dogs and cats in the 1960s also support the lack of a causative relationship between atelectasis and fever. 4,5 Although fever was observed within 12 hrs of placement of cotton plugs in the left main bronchus of these animals, almost all animals also developed pneumonia distal to the plug.  Antibiotic treatment was associated with resolution of fever but not atelectasis.

So if it’s not atelectasis, what’s the explanation for early postop fever? The great majority of postop fevers during the first 4 days postop are unlikely to be related to infections. Instead, a more plausible explanation is the inflammatory response to the tissue injury as a result of the surgery itself causing release of cytokines (eg, interleukin-1 and -6 and tumor necrosis factor) associated with fever. 6

References

  1. Mavros MN, Velmahos GC, Falagas ME. Atelectasis as a cause of postoperative fever. Where is the clinical evidence? CHEST 2011;140:418-24. https://www.ncbi.nlm.nih.gov/pubmed/21527508
  2. Roberts J, Barnes W, Pennock M, et al. Diagnostic accuracy of fever as a measure of postoperative pulmonary complications. Heart Lung 1988;17:166-70. https://www.ncbi.nlm.nih.gov/pubmed/3350683
  3. Engoren M. Lack of association between atelectasis and fever. CHEST 1995;107:81-84. https://www.ncbi.nlm.nih.gov/pubmed/7813318
  4. Lansing AM, Jamieson WG. Mechanisms of fever in pulmonary atelectasis. Arch Surg 1963;87:168-174. https://jamanetwork.com/journals/jamasurgery/fullarticle/561080
  5. Jamieson WG, Lansing AM. Bacteriological studies in pulmonary atelectasis. Arch Surg 1963;87:1062-66. https://www.ncbi.nlm.nih.gov/pubmed/14063816
  6. Narayan M, Medinilla SP. Fever in the postoperative patient. Emerg Med Clin Nam 2013;31:1045-58. https://www.ncbi.nlm.nih.gov/pubmed/24176478 

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My postop patient now has fever with atelectasis on her chest X-ray one day after surgery. Does atelectasis cause fever?

How can I tell if my febrile patient who uses IV drugs had cotton fever?

Although IV drug use (IVDU) is associated with febrile illness of numerous etiologies (eg, soft tissue infections, pneumonia, bacteremia, endocarditis), certain features of a febrile illness may be helpful in considering cotton fever (CF) as the cause.1-3

First, onset of fever—often associated with chills, shortness of breath, nausea, vomiting, headache, abdominal pain and myalgias—in CF is usually manifest within 10-30 minutes of drug injection. Second, infectious disease workup, including blood cultures and chest radiograph, are unrevealing despite clinical signs of systemic inflammatory response syndrome (SIRS), such as leukocytosis, tachypnea and tachycardia. Third, symptoms and clinical signs of inflammation usually resolve or improve within 6-12 h of onset (less commonly up to 24-48 h). Nevertheless, CF remains a diagnosis of exclusion.

As for the cause of CF, the most widely-held theory revolves around the endotoxin of Pentoea agglomerans (formerly Enterobacter agglomerans), a gram-negative rod that colonizes cotton plants. Since cotton is often used as a filter during injection of illicit substances, any endotoxin present in the cotton is also injected resulting in abrupt onset of a febrile illness. Of note, the toxin is water soluble and heating (often part of the preparation of the drug) enhances its toxic effect.3

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References

  1. Zerr AM, Ku K, Kara A. Cotton Fever: a condition self-diagnosed by IV drug users. JABFM 2016;29: 276-279.PDF
  2. Xie Y, Pope BA, Hunter AJ. Cotton fever: does the patient know best? J Gen Intern Med 31:442-4. PDF
  3. Torka P, Gill S. Cotton fever: an evanescent process mimicking sepsis in an intravenous drug abuser. J Emerg Med 2013;44:e385-e387. PDF
How can I tell if my febrile patient who uses IV drugs had cotton fever?

How accurate are peripheral thermometers for estimating body temperature in my patient with chills?

Though convenient, oral, tympanic membrane, axillary, and temporal artery thermometers (AKA “peripheral thermometers”) may not be highly accurate in measuring body temperature.

A 2015 systematic review and meta-analysis of the performance of peripheral thermometers involving 75 studies (mostly in adults) found that compared to central thermometers (eg, pulmonary artery, urinary bladder, rectal), peripheral thermometers had a low sensitivity (64%, 95% CI 55%-72%), but much better specificity (96%, 95% CI 93%-97%) for fever (most commonly defined as 37.8° C [100° F] or greater).1

In the same study, for oral electronic thermometers, sensitivity was 74% with a specificity of 86%. For temporal artery thermometers, sensitivities ranged from 26% to 91%, while specificities ranged from 67% to 100%. For tympanic membrane thermometers, sensitivities ranged from 23% to 87%, with a specificity of 57% to 99%.

A 2016 study involving adult emergency department patients reported the sensitivity of peripheral thermometers (vs rectal temperature 38 C [100.4] or higher) as follows: oral (37%), tympanic membrane (68%), and temporal artery (71%). Specificity for fever was >90% for all peripheral thermometers. 2

So, it looks like while we may be pretty comfortable with a diagnosis of “fever” when our patient with chills has a high temperature recorded by a peripheral thermometer, lack of fever alone by these devices should not veer us away from the possibility of systemic infection. When in doubt and if possible, check a rectal temperature.

References

  1. Niven DJ, Gaudet JE, Laupland KB. Accuracy of peripheral thermometers for estimating temperature: A systematic and meta-analysis. Ann Intern Med 2015;163:768-777. https://www.ncbi.nlm.nih.gov/pubmed/26571241
  2. Bijur PE, Shah PD, Esses D. Temperature measurement in the adult emergency department: oral tympanic membrane and temporal artery temperatures versus rectal temperature. Emerg Med J 2016;33:843-7. https://www.ncbi.nlm.nih.gov/pubmed/27334759

 

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How accurate are peripheral thermometers for estimating body temperature in my patient with chills?

My elderly nursing home patient is admitted with recent poor oral intake, falls and oral temperatures of 99.1°-99.3° F(37.3°-37.4°C). Is she considered febrile at these temperatures?

Yes! Even though we often think of temperatures of 100.4°F (38° C) or greater as fever, older people often fail to mount an appropriate febrile response despite having a serious infection. 1

Infectious Diseases Society of America (IDSA) guideline on evaluation of fever in older adult residents of long-term care facilities has defined fever in this population as:2

  • Single oral temperature >100° F (>37.8° C) OR
  • Repeated oral temperatures >99° F (>37.2° C) OR
  • Rectal temperatures >99.5° F (>37.5° C) OR
  • Increase in temperature of >2° F (>1.1° C) over the baseline temperature

Even at these lower than traditional thresholds for defining fever, remember that many infected elderly patients may still lack fever. In a study involving bacteremic patients, nearly 40% of those 80 years of age or older did not have fever (defined as maximum temperature over 24 hrs 100° F [37.8°C] or greater).3  

So our patient meets the criteria for fever as suggested by IDSA guidelines and, particularly in light of her recent poor intake and falls, may need evaluation for a systemic source of infection.

Now that’s interesting! Did you know that blunted febrile response of the aged to infections may be related to the inability of cytokines (eg, IL-1) to reach the central nervous system?1

References 

  1. Norman DC. Fever in the elderly. Clin Infect Dis 2000;31:148-51. https://academic.oup.com/cid/article/31/1/148/318030
  2. High KP, Bradley SF, Gravenstein S, et al. Clinical practice guidelines for the evaluation of fever and infection in older adult residents of long-term care facilities: 2008 update by the Infectious Disease Society of America. Clin Infect Dis 2009;48:149-71. http://www.idsociety.org/uploadedFiles/IDSA/Guidelines-Patient_Care/PDF_Library/Fever%20and%20Long%20Term%20Care.pdf
  3. Manian FA. Fever, abnormal white blood cell count, neutrophilia, and elevated serum C-reactive protein in adult hospitalized patients with bacteremia. South Med J 2012;105;474-78. http://europepmc.org/abstract/med/22948327
My elderly nursing home patient is admitted with recent poor oral intake, falls and oral temperatures of 99.1°-99.3° F(37.3°-37.4°C). Is she considered febrile at these temperatures?

Can I rely on the physical exam to rule out symptomatic urinary tract infection (UTI) in my hospitalized patient?

Suprapubic tenderness, costovertebral angle tenderness (CVAT) and fever seem to be more helpful in ruling in than ruling out infection. And, before you hang your hat on the available data, remember that most of the studies involve women with uncomplicated UTI in primary care or emergency department settings, not our older hospitalized patients at risk of complicated infections.  With these caveats in mind….

Suprapubic tenderness has been reported in only about 15-20% of women with acute cystitis. 1

CVAT has been associated with symptomatic UTI but with only a weakly positive LR (1.7, 1.1-2.5), and an insignificant negative LR. 2  In a single center study involving hospitalized patients (mean age 53 y), CVAT was either absent or “obscure” in about 10% of patients with acute pyelonephritis on CT.3

Fever was associated with a positive likelihood ratio (1.6, 1.0-2.6) by 1 systematic study 2 but not another, 4 with insignificant negative LR in both. Fever was also absent in about 10% of hospitalized patients with pyelonephritis in the single center study above.3

So, when evaluating a patient with possible symptomatic UTI (particularly cystitis), the presence of physical exam findings  may be more helpful than their absence.

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References

  1. Kurowski K. The woman with dysuria. Am Fam Physician 1998, 57:2155-2164. https://www.aafp.org/afp/1998/0501/p2155.html
  2. Bent S, Nallamothu BK, Simel DL, et al. Does this woman have an acute uncomplicated urinary tract infection? JAMA 2002;287:2701-2710. https://www.ncbi.nlm.nih.gov/pubmed/12020306
  3. Lee Y-J, Cho S, Kim SR. Unilateral and bilateral acute pyelonephritis: differences in clinical presentation, progress and outcome. Postgrad Med 2014;90:80-85. https://www.ncbi.nlm.nih.gov/pubmed/24255118
  4. Median-Bombardo D, Jover-Palmer A. Does clinical examination aid in the diagnosis of urinary tract infections in women? A systematic review and meta-analysis. BMC Family Practice 2011;12:111. https://bmcfampract.biomedcentral.com/articles/10.1186/1471-2296-12-111

 

Can I rely on the physical exam to rule out symptomatic urinary tract infection (UTI) in my hospitalized patient?

My previously healthy 55 year old patient is admitted with a respiratory tract infection and a respiratory rate of 22 breaths/min. Should I be concerned?

Any respiratory rate (RR) greater than 20/min in an adult patient may be cause for concern, particularly in the setting of potentially serious disease and absence of an obvious cause such as pain or fever.

Our patient’s RR is outside the commonly cited normal range of 12-20/min. It indicates increased alveolar ventilation which may in turn be caused by hypoxia, hypercapnea, or metabolic acidosis, all portending possibly poor outcome, if left untreated.It’s no surprise that an abnormal RR is often the first sign of clinical deterioration.2 RR is also the least likely of the vital signs to be affected by polypharmacy (eg, NSAIDs affecting temperature, beta-blockers affecting heart rate and blood pressure). 

Another reason for not dismissing an RR of 22 in our patient is the common practice of guessing rather than measuring the RR by healthcare providers in part likely due to the  more “labor-intensive” nature of measuring RRs compared to other vital signs and lack of appreciation for its importance in assessing severity of disease. 1 Of note, in an experimental study of doctors viewing videos of mock patients, over 50% failed to detect abnormal RR when using the “spot” technique of estimating without a timer.3 Even when presented with a RR of 30/min, over 20% of doctors reported it as normal (12-20/min)!

Final tidbit: Do you want to know what a RR of 20/min really feels like? Take a breath every 3 seconds.  If you are like most, it doesn’t feel “normal”!

References
1. Cretikos MA, Bellomo R, Hillman K. Respiratory rate: the neglected vital sign. MJA 2008;188:657-59. https://www.ncbi.nlm.nih.gov/pubmed/18513176
2. Flenady T, Dwer T, Applegarth J. Accurate respiratory rates count: So should you! Australas Emerg Nurs J 2017; 20:45-47. https://www.ncbi.nlm.nih.gov/pubmed/28073649
3. Philip KEJ, Pack E, Cambiano V et al. The accuracy of respiratory rate assessment by doctors in a London teaching hospital: a cross-sectional study. J Clin Monit Comput2015;29:455-60. https://www.ncbi.nlm.nih.gov/pubmed/25273624

My previously healthy 55 year old patient is admitted with a respiratory tract infection and a respiratory rate of 22 breaths/min. Should I be concerned?