Trauma mortality and systolic BP

Here’s some further evidence that a ‘lowish’ – as opposed to a low – systolic blood pressure is a reason to be vigilant in trauma. In this study, it was BP measurement in the ED (rather than pre-hospital) that was assessed:


Introduction: Non-invasive systolic blood pressure (SBP) measurement is often used in triaging trauma patients. Traditionally, SBP < 90 mmHg has represented the threshold for hypotension, but recent studies have suggested redefining hypotension as SBP < 110 mmHg. This study aims to examine the association of SBP with mortality in blunt trauma patients.
Methods: This is an analysis of prospectively recorded data from adult (≥16 years) blunt trauma patients. Included patients presented to hospitals belonging to the Trauma Audit and Research Network (TARN) between 2000 and 2009. The primary outcome was the association of SBP and mortality rates at 30 days. Multivariate logistic regression models were used to adjust for the influence of age, gender, Injury Severity Score (ISS) and Glasgow Coma Score (GCS) on mortality.

Results: 47,927 eligible patients presented to TARN hospitals during the study period. Sample demographics were: median age: 51.1 years (IQR=32.8–67.4); male 60% (n=28,694); median ISS 9 (IQR = 8–10); median GCS 15 (IQR = 15–15); and median SBP 135 mmHg (IQR = 120–152). We identified SBP < 110 mmHg as a cut off for hypotension, where a significant increase in mortality was observed. Mor- tality rates doubled at <100 mmHg, tripled at <90 mmHg and were 5- to 6-fold at <70 mmHg, irrespective of age.
Conclusion: We recommend triaging adult blunt trauma patients with a SBP < 110 mmHg to resuscitation areas within dedicated trauma units for close monitoring and appropriate management.

Systolic blood pressure below 110mmHg is associated with increased mortality in blunt major trauma patients: Multicentre cohort study
Resuscitation. 2011 Sep;82(9):1202-7

Score to predict traumatic coagulopathy

Acute traumatic coagulopathy (ATC) is present in up to 25% of major trauma patients by the time they arrive in hospital. A predictive tool called the coagulopathy of severe trauma (COAST) score was retrospectively derived and then prospectively validated in major trauma patients in the state of Victoria, Australia. The definition of ATC was INR > 1.5 (1.0–1.3) or aPTT of > 60 s (25–38 s) on hospital presentation.
The study claims that a subgroup of patients with acute traumatic coagulopathy can be accurately identified based on simple observations in the pre-hospital phase or immediately on presentation to the ED, and that this could improve the feasibility of prospective interventional studies. Perhaps this will lead on to evaluation of pre-hospital tranexamic acid or even blood products?
At the cutoff score of ≥3, 40 coagulopathic patients would have been missed with 60 patients correctly predicted. The authors argue that while the low sensitivity of the score missed these coagulopathic patients, they had significantly better outcomes (and contained a significantly higher proportion of patients with isolated severe head injury).


Introduction: The inability to accurately predict acute traumatic coagulopathy (ATC) has been a key factor in the low level of evidence guiding its management. The aim of this study was to develop a tool to accurately identify patients with ATC using pre-hospital variables without the use of pathology or radiological testing.

Methods: Retrospective data from the trauma registry on major trauma patients were used to identify vari- ables independently associated with coagulopathy. These variables were clinically evaluated to develop a scoring system to predict ATC, which was prospectively validated in the same setting.

Results: There were 1680 major trauma patients in the derivation dataset, with 151 patients being coagulopathic. Pre-hospital variables independently associated with ATC were entrapment (OR 1.85; 95% CI: 1.12–3.06), temperature (OR 0.60; 95% CI: 0.60–0.72), systolic blood pressure (OR 0.99; 95% CI: 0.98–0.99), abdominal or pelvic content injury (OR 2.0; 95% CI: 1.27–3.12) and pre-hospital chest decompression (OR 4.99; 2.77–8.99). The COAST score was developed, scoring points for entrapment, temperature <35 ◦ C, systolic blood pressure <100 mm Hg, abdominal or pelvic content injury and chest decompression. Prospectively validated using 1225 major trauma patients, a COAST score of ≥3 had a specificity of 96.4% with a sensitivity of 60.0%, with an area under the receiver operating characteristic curve of 0.83 (0.78–0.88).
Conclusions: The COAST score accurately identified a group of patients with ATC using pre-hospital obser- vations. This predictive tool can be used to select patients for inclusion into prospective studies examining management options for ATC. Mortality in these patients is high, potentially improving feasibility of outcome studies.

Still no cardiac arrest survival benefit from epinephrine?

A double blind randomised controlled trial showed significantly better rates of return of spontaneous circulation and hospital admission with the use of adrenaline (epinephrine) compared with placebo. This effect was observed with both shockable and non-shockable initial cardiac arrest rhythms. There was no statistically significant difference in the primary outcome of survival to hospital discharge.
Interesting but unfortunate political factors appear to have prevented recruitment to the required numbers of patients for this study so it is underpowered for its primary outcome of survival to hospital discharge, which in the adrenaline group was double that in the placebo group, although this did not reach statistical significance. What was supposed to be a multi-centre study became a single centre one and it was not possible to continue as the study drugs reached their expiry date and no additional funding was available.
So do ROSC and survival to admission matter? The authors make the following point:


While not the primary outcome of our study, ROSC is an increasingly important clinical endpoint as the influence of post resuscitation care interventions (i.e.: therapeutic hypothermia, managing underlying cause, organ perfusion and oxygenation) on survival to hospital discharge are recognised.

Optimum dose and timing of adrenaline remain unknown, along with whether it impacts on long-term outcomes.


BACKGROUND: There is little evidence from clinical trials that the use of adrenaline (epinephrine) in treating cardiac arrest improves survival, despite adrenaline being considered standard of care for many decades. The aim of our study was to determine the effect of adrenaline on patient survival to hospital discharge in out of hospital cardiac arrest.

METHODS: We conducted a double blind randomised placebo-controlled trial of adrenaline in out-of-hospital cardiac arrest. Identical study vials containing either adrenaline 1:1000 or placebo (sodium chloride 0.9%) were prepared. Patients were randomly allocated to receive 1ml aliquots of the trial drug according to current advanced life support guidelines. Outcomes assessed included survival to hospital discharge (primary outcome), pre-hospital return of spontaneous circulation (ROSC) and neurological outcome (Cerebral Performance Category Score – CPC).

RESULTS: A total of 4103 cardiac arrests were screened during the study period of which 601 underwent randomisation. Documentation was available for a total of 534 patients: 262 in the placebo group and 272 in the adrenaline group. Groups were well matched for baseline characteristics including age, gender and receiving bystander CPR. ROSC occurred in 22 (8.4%) of patients receiving placebo and 64 (23.5%) who received adrenaline (OR=3.4; 95% CI 2.0-5.6). Survival to hospital discharge occurred in 5 (1.9%) and 11 (4.0%) patients receiving placebo or adrenaline respectively (OR=2.2; 95% CI 0.7-6.3). All but two patients (both in the adrenaline group) had a CPC score of 1-2.

CONCLUSION: Patients receiving adrenaline during cardiac arrest had no statistically significant improvement in the primary outcome of survival to hospital discharge although there was a significantly improved likelihood of achieving ROSC.

Effect of adrenaline on survival in out-of-hospital cardiac arrest: A randomised double-blind placebo-controlled trial
Resuscitation. 2011 Sep;82(9):1138-43

Pre-hospital ECMO

Two cases are reported of the pre-hospital institution of venoarterial extracorporeal membrane oxygenation (ECMO) for patients in cardiac arrest. One was from France and the other from Germany – both countries with mature physician-staffed pre-hospital systems. The two cases were a 9 yr old drowning victim1 and a 48 year old marathon runner2. They each received BLS then ACLS then ECMO, and both went from asystole to sinus rhythm after the institution of ECMO. Sadly both failed to neurologically recover and died in hospital.
If irreversible anoxic encephalopathy could be detected in the field, patients could be better selected for this intervention. An editorialist3 states:


Until we have a hand held device which can measure neuronal integrity on a cellular level in the field we must use our best judgement, and in many cases give the patient the benefit of the doubt by cannulating them, cooling for 24 h and then making a neurological assessment and withdrawing ECLS if necessary.

Other issues to consider are:

  • Can society afford this level of intervention?
  • Could this intervention, when associated with brain death, result in sufficiently recovered organs for transplantation?
  • How can the infrastructure be created to enable rapid institution of pre-hospital ECMO?

I suspect as the equipment becomes even more portable and self-maintaining, pre-hospital / retrieval physicians already expert in critical care interventions such as seldinger-guided vascular access will be the ones instituting this therapy. In the meantime, we await evidence of outcome benefit and some objective means of case selection.
1. Out-of-hospital extracorporeal life support for cardiac arrest—A case report
Resuscitation. 2011 Sep;82(9):1243-5
2. Out-of-hospital extra-corporeal life support implantation during refractory cardiac arrest in a half-marathon runner
Resuscitation. 2011 Sep;82(9):1239-42
3. Community extracorporeal life support for cardiac arrest – When should it be used?
Resuscitation. 2011 Sep;82(9):1117

Mouth-to-nose breathing

Interesting – mouth to nose breathing was more effective than mouth-to-mouth in simulated resuscitations using anaesthetised, apnoeic patients:


BACKGROUND: The authors hypothesized that mouth ventilation by a resuscitator via the nasal route ensures a more patent airway and more effective ventilation than does ventilation via the oral route and therefore would be the optimal manner to ventilate adult patients in emergencies, such as during cardiopulmonary resuscitation. They tested the hypothesis by comparing the effectiveness of mouth-to-nose breathing (MNB) and mouth-to-mouth breathing (MMB) in anesthetized, apneic, adult subjects without muscle paralysis.

METHODS: Twenty subjects under general anesthesia randomly received MMB and MNB with their heads placed first in a neutral position and then an extended position. A single operator performed MNB and MMB at the target breathing rate of 10 breaths/min, inspiratory:expiratory ratio 1:2 and peak inspiratory airway pressure 24 cm H₂O. A plethysmograph was used to measure the amplitude change during MMB and MNB. The inspiratory and expiratory tidal volumes during MMB and MNB were calculated retrospectively using the calibration curve.

RESULTS: All data are presented as medians (interquartile ranges). The rates of effective ventilation (expired volume > estimated anatomic dead space) during MNB and MMB were 91.1% (42.4-100%) and 43.1% (42.5-100%) (P < 0.001), and expired tidal volume with MMB 130.5 ml (44.0-372.8 ml) was significantly lower than with MNB 324.5 ml (140.8-509.0 ml), regardless of the head position (P < 0.001).
CONCLUSIONS: Direct mouth ventilation delivered exclusively via the nose is significantly more effective than that delivered via the mouth in anesthetized, apneic adult subjects without muscle paralysis. Additional studies are needed to establish whether using this breathing technique during emergency situations will improve patient outcomes.

Effectiveness of breathing through nasal and oral routes in unconscious apneic adult human subjects: a prospective randomized crossover trial
Anesthesiology. 2011 Jul;115(1):129-35

Glutamine in ICU

Of interest to intensivists….


Background: Low plasma glutamine concentration is an independent prognostic factor for an unfavourable outcome in the intensive care unit (ICU). Intravenous (i.v.) supplementation with glutamine is reported to improve outcome. In a multi-centric, double-blinded, controlled, randomised, pragmatic clinical trial of i.v. glutamine supplementation for ICU patients, we investigated outcomes regarding sequential organ failure assessment (SOFA) scores and mortality. The hypothesis was that the change in the SOFA score would be improved by glutamine supplementation.

Methods: Patients (n=413) given nutrition by an enteral and/or a parenteral route with the aim of providing full nutrition were included within 72 h after ICU admission. Glutamine was supplemented as i.v. l-alanyl-l-glutamine, 0.283 g glutamine/kg body weight/24 h for the entire ICU stay. Placebo was saline in identical bottles. All included patients were considered as intention-to-treat patients. Patients given supplementation for >3 days were considered as predetermined per protocol (PP) patients.

Results: There was a lower ICU mortality in the treatment arm as compared with the controls in the PP group, but not at 6 months. For change in the SOFA scores, no differences were seen, 1 (0,3) vs. 2 (0.4), P=0.792, for the glutamine group and the controls, respectively.

Conclusion: In summary, a reduced ICU mortality was observed during i.v. glutamine supplementation in the PP group. The pragmatic design of the study makes the results representative for a broad range of ICU patients.

Scandinavian glutamine trial: a pragmatic multi-centre randomised clinical trial of intensive care unit patients
Acta Anaesthesiol Scand. 2011 Aug;55(7):812-818

Nitric oxide for right ventricular cardiogenic shock

A case report describes a patient with right ventricular cardiogenic shock due to a dissected right coronary artery1. There was deterioration despite fluid, inotropic and intraaortic balloon pump therapy, followed by improvement with the introduction of inhaled nitric oxide (iNO) at 12 to 15 ppm (a selective pulmonary vasodilator), to the point where vasoactive medication was withdrawn. The cessation of iNO was associated with deterioration which resolved with its reintroduction. It was more gradually withdrawn and the patient made a good recovery.
The rationale for the use of iNO in patients with acute RV heart failure due to MI is afterload reduction without systemic hypotension.
It has been shown to improve haemodynamics in RV MI patients with cardiogenic shock in a previous case series2 (abstract below) in which its effects on pulmonary vasodilation are thought be beneficial. In RV MI with shock increased pulmonary vascular tone is postulated to result from the following mechanisms:

  • A low cardiac output results in a decreased mixed venous blood oxygen content, which enhances pulmonary artery vasoconstriction.
  • The intravenous infusion of alpha-adrenergic vasoconstrictors can contribute to pulmonary vasoconstriction.
  • Mechanical ventilation with positive end-expiratory pressure can increase the pulmonary vascular resistance through compression of the pulmonary vasculature.
  • Interstitial pulmonary edema, which may occur in some patients with coexisting LV dysfunction, can also cause pulmonary constriction

OBJECTIVES: We sought to determine whether or not inhaled nitric oxide (NO) could improve hemodynamic function in patients with right ventricular myocardial infarction (RVMI) and cardiogenic shock (CS).

BACKGROUND: Inhaled NO is a selective pulmonary vasodilator that can decrease right ventricular afterload.

METHODS: Thirteen patients (7 males and 6 females, age 65 +/- 3 years) presenting with electrocardiographic, echocardiographic, and hemodynamic evidence of acute inferior myocardial infarction associated with RVMI and CS were studied. After administration of supplemental oxygen (inspired oxygen fraction [F(i)O(2)] = 1.0), hemodynamic measurements were recorded before, during inhalation of NO (80 ppm at F(i)O(2) = 0.90) for 10 min, and 10 min after NO inhalation was discontinued (F(i)O(2) = 1.0).

RESULTS: Breathing NO decreased the mean right atrial pressure by 12 +/- 3%, mean pulmonary arterial pressure by 13 +/- 2%, and pulmonary vascular resistance by 36 +/- 8% (all p < 0.05). Nitric oxide inhalation increased the cardiac index by 24 +/- 11% and the stroke volume index by 23 +/- 12% (p < 0.05). The NO administration did not change systemic arterial or pulmonary capillary wedge pressures. Contrast echocardiography identified three patients with a patent foramen ovale and right-to-left shunt flow while breathing at F(i)O(2) = 1.0. Breathing NO decreased shunt flow by 56 +/- 5% (p < 0.05) and was associated with markedly improved systemic oxygen saturation.

CONCLUSIONS: Nitric oxide inhalation results in acute hemodynamic improvement when administered to patients with RVMI and CS.

1. Use of inhaled nitric oxide in the treatment of right ventricular myocardial infarction
Am J Emerg Med. 2011 May;29(4):473.e3-5
2. Hemodynamic effects of inhaled nitric oxide in right ventricular myocardial infarction and cardiogenic shock
J Am Coll Cardiol. 2004 Aug 18;44(4):793-8

Surgeons and trauma teams

There can be issues associated with calling surgeons to trauma team activations in the ED, including interruption to the surgeon’s other duties, and the absence of anything useful for the surgeon to do, when most blunt trauma patients are managed by emergency physicians, intensivists, and orthopaedic surgeons, with a growing input from interventional radiologists. At one American major trauma centre for example, emergency operation by a trauma surgeon for blunt trauma averages once every 7 weeks for adults and less than once every 3 years for children1.
While there are many surgeons who are passionate about trauma care and excellent in the non-operative aspects of trauma management, there are probably more who would welcome measures to reduce the need to attend ED for all trauma team activations. Of course no triage tool is perfect: they will always have to trade sensitivity against specificity. One such tool from the Loma Linda University Medical Center uses the simple criteria of penetrating trauma, systolic blood pressure, and heart rate. These pertain to pre-hospital measurement and therefore the surgeon can be activated prior to patient arrival.
This triage tool performed better than the American College of Surgeons’ “major resuscitation” trauma triage criteria2:


STUDY OBJECTIVE: Trauma centers use “secondary triage” to determine the necessity of trauma surgeon involvement. A clinical decision rule, which includes penetrating injury, an initial systolic blood pressure less than 100 mm Hg, or an initial pulse rate greater than 100 beats/min, was developed to predict which trauma patients require emergency operative intervention or emergency procedural intervention (cricothyroidotomy or thoracotomy) in the emergency department. Our goal was to validate this rule in an adult trauma population and to compare it with the American College of Surgeons’ major resuscitation criteria.

METHODS: We used Level I trauma center registry data from September 1, 1995, through November 30, 2008. Outcomes were confirmed with blinded abstractors. Sensitivity, specificity, and 95% confidence intervals (CIs) were calculated.

RESULTS: Our patient sample included 20,872 individuals. The median Injury Severity Score was 9 (interquartile range 4 to 16), 15.3% of patients had penetrating injuries, 13.5% had a systolic blood pressure less than 100 mm Hg, and 32.5% had a pulse rate greater than 100 beats/min. Emergency operative intervention or procedural intervention was required in 1,099 patients (5.3%; 95% CI 5.0% to 5.6%). The sensitivities and specificities of the rule and the major resuscitation criteria for predicting emergency operative intervention or emergency procedural intervention were 95.6% (95% CI 94.3% to 96.8%) and 56.1% (95% CI 55.4% to 56.8%) and 85.5% (95% CI 83.3% to 87.5%) and 80.9% (95% CI 80.3% to 81.4%), respectively.

CONCLUSION: This new rule was more sensitive for predicting the need for emergency operative intervention or emergency procedural intervention directly compared with the American College of Surgeons’ major resuscitation criteria, which may improve the effectiveness and efficiency of trauma triage.

Although not mentioned in the abstract, the study also included assessment of refinements of the Loma Linda Rule based on different cutoffs of heart rate and blood pressure. Once such refinement that included penetrating injury to the torso and less conservative physiological criteria (systolic blood pressure <90 mm Hg and pulse rate >110 beats/min) resulted in a slightly lower sensitivity, with a dramatic improvement in specificity compared with the original Loma Linda Rule.
A good point is made by Steve Green in his accompanying editoral3:


A possibility is that emergency physicians supervising out-of-hospital radio calls can predict the need for surgeon presence just as accurately (or perhaps more accurately) as any of these rules. After all, judgment is the time-tested mechanism by which emergency physicians summon all other consultants for all other conditions.

Unfortunately for many UK and Australasian centres, the challenge that remains is not deciding when to call the surgeon, but getting one when you do call, preferable one who is not committed to an elective operating list and one who has some training and experience in trauma surgery.
1. Clinical decision rules for secondary trauma triage: predictors of emergency operative management.
Ann Emerg Med. 2006 Feb;47(2):135
2. Validation and refinement of a rule to predict emergency intervention in adult trauma patients
Ann Emerg Med. 2011 Aug;58(2):164-71
3. Trauma is occasionally a surgical disease: how can we best predict when?
Ann Emerg Med. 2011 Aug;58(2):172-177

Ultrasound to detect difficult laryngoscopy

A pilot study suggests sonographic measurements of neck soft tissue thickness may predict difficult laryngoscopy. Laryngoscopy was difficult in patients with increased thickness of the anterior neck soft tissue at the level of the hyoid bone and thyrohyoid membrane. The authors suggest that anterior neck soft tissue thickness cutoff value of 2.8 cm at the thyrohyoid membrane level can potentially be used to detect difficult laryngoscopy, but that this would require further validation since in this pilot study there were only six subjects in the difficult laryngoscopy group.


Objectives:  Prediction of difficult laryngoscopy in emergency care settings is challenging. The preintubation clinical screening tests may not be applied in a large number of emergency intubations due to the patient’s clinical condition. The objectives of this study were 1) to determine the utility of sonographic measurements of thickness of the tongue, anterior neck soft tissue at the level of the hyoid bone, and thyrohyoid membrane in distinguishing difficult and easy laryngoscopies and 2) to examine the association between sonographic measurements (thickness of tongue and anterior neck soft tissue) and difficult airway clinical screening tests (modified Mallampati score, thyromental distance, and interincisor gap).

Methods:  This was a prospective observational study at an academic medical center. Adult patients undergoing endotracheal intubation for an elective surgical procedure were included. The investigators involved in data collection were blinded to each other’s assessments. Demographic variables were collected preoperatively. The clinical screening tests to predict a difficult airway were performed. The ultrasound (US) measurements of tongue and anterior neck soft tissue were obtained. The laryngoscopic view was graded using Cormack and Lehane classification by anesthesia providers on the day of surgery. To allow for comparisons between difficult airway and easy airway groups, a two-sided Student’s t-test and Fisher’s exact test were employed as appropriate. Spearman’s rank correlation coefficients were used to examine the association between screening tests and sonographic measurements.

Results:  The mean (±standard deviation [SD]) age of 51 eligible patients (32 female, 19 male) was 53.1 (±13.2) years. Six of the 51 patients (12%, 95% confidence interval [CI] = 3% to 20%) were classified as having difficult laryngoscopy by anesthesia providers. The distribution of laryngoscopy grades for all subjects was 63, 25, 4, and 8% for grades 1, 2, 3, and 4, respectively. In this study, 83% of subjects with difficult airways were males. No other significant differences were noted in the demographic variables and difficult airway clinical screening tests between the two groups. The sonographic measurements of anterior neck soft tissue were greater in the difficult laryngoscopy group compared to the easy laryngoscopy group at the level of the hyoid bone (1.69, 95% CI = 1.19 to 2.19 vs. 1.37, 95% CI = 1.27 to 1.46) and thyrohyoid membrane (3.47, 95% CI = 2.88 to 4.07 vs. 2.37, 95% CI = 2.29 to 2.44). No significant correlation was found between sonographic measurements and clinical screening tests.

Conclusions:  This pilot study demonstrated that sonographic measurements of anterior neck soft tissue thickness at the level of hyoid bone and thyrohyoid membrane can be used to distinguish difficult and easy laryngoscopies. Clinical screening tests did not correlate with US measurements, and US was able to detect difficult laryngoscopy, indicating the limitations of the conventional screening tests for predicting difficult laryngoscopy.

Pilot Study to Determine the Utility of Point-of-care Ultrasound in the Assessment of Difficult Laryngoscopy
Acad Emerg Med. 2011 Jul;18(7):754-8

Ultrasound-Guided Radial Artery Catheterization


In case you needed some evidence – a systematic review supports ultrasound guidance as a means of improving insertion success of radial artery catheters


BACKGROUND: Ultrasound guidance commonly is used for the placement of central venous catheters (CVCs). The Agency for Healthcare Research and Quality recommends the use of ultrasound for CVC placement as one of its 11 practices to improve patient care. Despite increased access to portable ultrasound machines and comfort with ultrasound-guided CVC access, fewer clinicians are familiar with ultrasound-guided techniques of arterial catheterization. The goal of this systematic review and meta-analysis was to determine the utility of real-time two-dimensional ultrasound guidance for radial artery catheterization.

METHODS: A comprehensive literature search of Medline, Excerpta Medica Database, and the Cochrane Central Register of Controlled Trials by two independent reviewers identified prospective, randomized controlled trials comparing ultrasound guidance with traditional palpation techniques of radial artery catheterization. Data were extracted on study design, study size, operator and patient characteristics, and the rate of first-attempt success. A meta-analysis was constructed to analyze the data.

RESULTS: Four trials with a total of 311 subjects were included in the review, with 152 subjects included in the palpation group and 159 in the ultrasound-guided group. Compared with the palpation method, ultrasound guidance for arterial catheterization was associated with a 71% improvement in the likelihood of first-attempt success (relative risk, 1.71; 95% CI, 1.25-2.32).

CONCLUSIONS: The use of real-time two-dimensional ultrasound guidance for radial artery catheterization improved first-pass success rate.

Ultrasound-Guided Catheterization of the Radial Artery
Chest. 2011 Mar;139(3):524-9