Tag Archives: ALS

Pre-hospital Echo

Pre-hospital physicians in Germany performed basic echo on patients with symptoms either of profound hypotension and/or severe dyspnoea/tachypnoea where judged by the physician to be in a ‘peri-resuscitation’ state, and on patients undergoing CPR. Features noted were; cardiac motion (present or absent), ventricular function (normal, moderately impaired, severely impaired, absent), right ventricular dilatation or pericardial collection.
A few interesting findings to note:

  • In almost all patients an interpretable view was achieved; in the CPR patients, the subcostal view was best
  • In PEA patients, there was a difference in survival to admission (to discharge isn’t documented) between those with and without sonographically evident cardiac wall motion (21/38 = 55% vs 1/13 = 8%)
  • In ‘suspected asystole’, some patients had sonographically evident cardiac wall motion, and 9/37 (24%) of these survived to hospital admission vs 4/37 (11%) with no wall motion. On this point, the authors note: ‘The ECG performance and interpretation were by experienced practitioners, and this therefore raises questions regarding the accuracy of an ECG diagnosis of asystole in the pre-hospital setting‘.

Purpose of the study: Focused ultrasound is increasingly used in the emergency setting, with an ALS- compliant focused echocardiography algorithm proposed as an adjunct in peri-resuscitation care (FEEL). The purpose of this study was to evaluate the feasibility of FEEL in pre-hospital resuscitation, the incidence of potentially treatable conditions detected, and the influence on patient management.
Patients, materials and methods: A prospective observational study in a pre-hospital emergency setting in patients actively undergoing cardio-pulmonary resuscitation or in a shock state. The FEEL protocol was applied by trained emergency doctors, following which a standardised report sheet was completed, including echo findings and any echo-directed change in management. These reports were then analysed independently.
Results: A total of 230 patients were included, with 204 undergoing a FEEL examination during ongoing cardiac arrest (100) and in a shock state (104). Images of diagnostic quality were obtained in 96%. In 35% of those with an ECG diagnosis of asystole, and 58% of those with PEA, coordinated cardiac motion was detected, and associated with increased survival. Echocardiographic findings altered management in 78% of cases.
Conclusions: Application of ALS-compliant echocardiography in pre-hospital care is feasible, and alters diagnosis and management in a significant number of patients. Further research into its effect on patient outcomes is warranted.
Focused echocardiographic evaluation in life support and peri-resuscitation of
emergency patients: A prospective trial

Resuscitation. 2010 Nov;81(11):1527-33

CPR on your own? Stay at the head end

In this manikin study, single-rescuer bag-mask ventilation (BMV) with chest compressions was tried in three different positions. Staying at the head end to deliver effective BMV, with ‘over-the-head’ chest compressions from that position, was best.

Background The 2005 guidelines for cardiopulmonary resuscitation (CPR) do not include a statement on performance of basic life support by a single healthcare professional using a bagevalveemask device. Three positions are possible: chest compressions and ventilations from over the head of the casualty (over-the-head CPR), from the side of the casualty (lateral CPR), and chest compressions from the side and ventilations from over the head of the casualty (alternating CPR). The aim of this study was to compare CPR quality of these three positions.
Methods 102 healthcare professionals were randomised to a crossover design and performed a 2-min CPR test on a manikin for each position.
Results The hands-off time over a 2-min interval was not significantly different between over-the-head (median 31 s) and lateral (31 s) CPR, but these compared favourably with alternating CPR (36 s). Over-the-head CPR resulted in significantly more chest compressions (155) compared with lateral (152) and alternating CPR (149); the number of correct chest compressions did not differ significantly (119 vs 122 vs 109). Alternating CPR resulted in significantly less inflations (eight) compared with over-the-head (ten) and lateral CPR (ten). Lateral CPR led to significantly less correct inflations (three) compared with over-the-head (five) and alternating CPR (four).
Conclusions In the case of a single healthcare professional using a bagevalveemask device, the quality of over-the-head CPR is at least equivalent to lateral, and superior to alternating CPR. Because of the potential difficulties in bagevalveemask ventilation in the lateral position, the authors recommend over-the-head CPR.
Comparison of the over-the-head, lateral and alternating positions during cardiopulmonary resuscitation performed by a single rescuer with a bag valve mask device
Emerg Med J. 2010 Oct 14. [Epub ahead of print]

How to give cold saline in the field

Pre-hospital therapeutic hypothermia might be a good thing, but there may be difficulties in achieving it if the 4 degrees C saline warms up during the infusion. What’s the optimal way of administering it? Czech investigators attempt to answer the question:
Background The cooling efficacy of intravenous administration of cold crystalloids can be enhanced by optimisation of the procedure. This study assessed the temperature stability of different application regimens of cold normal saline (NS) in simulated prehospital conditions.

Methods Twelve different application regimens of 4°C cold NS (volumes of 250, 500 and 1000 ml applied at infusion rates of 1000, 2000, 4000 and 6000 ml/h) were investigated for infusion temperature changes during administration to an artificial detention reservoir in simulated prehospital conditions.
Results An increase in infusion temperature was observed in all regimens, with an average of 8.163.38C (p<0.001). This was most intense during application of the residual 20% of the initial volume. The lowest rewarming was exhibited in regimens with 250 and 500 ml bags applied at an infusion rate of 6000 ml/h and 250 ml applied at 4000 ml/h. More intense, but clinically acceptable, rewarming presented in regimens with 500 and 1000 ml bags administered at 4000 ml/h, 1000 ml at 6000 ml/h and 250 ml applied at 2000 ml/h. Other regimens were burdened by excessive rewarming.
Conclusion Rewarming of cold NS during application in prehospital conditions is a typical occurrence. Considering that the use of 250 ml bags means the infusion must be exchanged too frequently during cooling, the use of 500 or 1000 ml NS bags applied at an infusion rate of $4000 ml/h and termination of the infusion when 80% of the infusion volume has been administered is regarded as optimal.
Prehospital cooling by cold infusion: searching for the optimal infusion regimen
Emerg Med J. 2010 Aug 23. [Epub ahead of print]

End tidal CO2 in cardiac arrest

Measuring end-tidal CO2 in cardiac arrest patients is helpful for

  1. confirming tracheal tube placement
  2. assessing the effectiveness of chest compressions
  3. predicting likelihood of return of spontaneous circulation (ROSC), in that a persistently low ETCO2 tends to predict death, whereas a high or rising ETCO2 is associated with a higher chance of ROSC.

It may be however that its predictive ability depends on the type of cardiac arrest, and how far into the resuscitation you’ve got when you measure the ETCO2. Consider this new study from Slovenian pre-hospital emergency physicians:
Methods: The study included two cohorts of patients: cardiac arrest due to asphyxia with initial rhythm asystole or pulseless electrical activity (PEA), and cardiac arrest due to arrhythmia with initial rhythm VF or pulseless VT. The causes of asphyxia were: asthma, severe acute respiratory failure, tumor of the airway, suicide by hanging, acute intoxication, pneumonia and a foreign body in the airway.PetCO2 was measured for both groups immediately after intubation and repeatedly every minute, both for patients with or without return of spontaneous circulation (ROSC). We compared the dynamic pattern of PetCO2 between groups. Resuscitation procedures were performed by an emergency medical team (emergency medical physician and two emergency medical technicians or registered nurses) in accordance with 2005 ERC Guideline
Results: Between June 2006 and June 2009 resuscitation was attempted in 325 patients and in this study we included 51 patients with asphyxial cardiac arrest and 63 patients with VF/VT cardiac arrest. The initial values of PetCO2 were significantly higher in the group with asphyxial cardiac arrest (6.74 ± 4.22 kilopascals (kPa) versus 4.51 ± 2.47 kPa; P = 0.004). In the group with asphyxial cardiac arrest, the initial values of PetCO2 did not show a significant difference when we compared patients with and without ROSC (6.96 ± 3.63 kPa versus 5.77 ± 4.64 kPa; P = 0.313). We confirmed significantly higher initial PetCO2 values for those with ROSC in the group with primary cardiac arrest (4.62 ± 2.46 kPa versus 3.29 ± 1.76 kPa; P = 0.041).

A significant difference in PetCO2 values for those with and without ROSC was achieved after five minutes of CPR in both groups (asphyxial arrest: 6.09 ± 2.63 kPa versus 4.47 ± 3.35 kPa; P = 0.006; primary arrest: 5.63 ± 2.01 kPa versus 4.26 ± 1.86; P = 0.015)
In mmHg, the PetCO2 values for those with and without ROSC after five minutes of CPR was: asphyxial arrest: 42.3 ± 20 mmHg versus 34 ± 25.5 mmHg; P = 0.006; primary arrest: 42.8 ± 15.3 mmHg versus 32.3 ± 14.1 mmHg; P = 0.015
Graphically, this difference in ROSC vs non-ROSC PetCO2 for both groups appeared to be even greater at ten minutes, with higher statistically significance (p<0.001), although the values of PetCO2 are not given in the paper.
In all patients with ROSC the initial PetCO2 was again higher than 1.33 kPa (10.1 mmHg).
Conclusions: The dynamic pattern of PetCO2 values during out-of-hospital CPR showed higher values of PetCO2 in the first two minutes of CPR in asphyxia, and a prognostic value of initial PetCO2 only in primary VF/VT cardiac arrest. A prognostic value of PetCO2 for ROSC was achieved after the fifth minute of CPR in both groups and remained present until final values. This difference seems to be a useful criterion in pre-hospital diagnostic procedures and attendance of cardiac arrest.
The authors summarise with the following key messages:

  • Initial values of PetCO2 are higher in asphyxial cardiac arrest than in primary cardiac arrest.
  • Initial values of PetCO2 in asphyxial cardiac arrest do not have a prognostic value for resuscitation outcome.
  • The prognostic value of PetCO2 for ROSC was achieved after the fifth minute of CPR in both groups and remained present until the final values.
  • The values of PetCO2 seem to be useful in differentiating the causes of cardiac arrest in a pre-hospital setting.

I think that last one’s a bit of a stretch. For me, this paper confirms that the longer you are into a cardiac arrest resuscitation, the worse news a low PetCO2 is. The lack of predictive value of initial PetCO2, particularly in the asphyxia group, is interesting but not surprising.
The dynamic pattern of end-tidal carbon dioxide during cardiopulmonary resuscitation: difference between asphyxial cardiac arrest and ventricular fibrillation/pulseless ventricular tachycardia cardiac arrest
Critical Care 2011, 15:R13

Pre-hospital therapeutic hypothermia

A Czech study demonstrated effective pre-hospital therapeutic cooling of post-cardiac arrest patients using fairly modest amounts of intravenous saline at 4°C: the administration of 12.6 ± 6.4 mL/kg (1,032 ± 546 mL) of 4°C normal saline led to a tympanic temperature decrease of 1.4 ± 0.8°C (from 36.2 ± 1.5 to 34.7 ± 1.4°C; P < 0.001) in 42.8 ± 19.6 minutes. No ice packs were applied.

Before other emergency medical services adopt this, it should be noted that all these patients were managed in the field by emergency physicians who administered sedatives and neuromuscular blockers. It’s a European thing.
Pre-hospital cooling of patients following cardiac arrest is effective using even low volumes of cold saline
Critical Care 2010, 14:R231 Full text

Better outcomes with conventional CPR

A very large nationwide Japanese observational study examined outcomes in out-of-hospital cardiac arrest patients who received CPR from lay rescuers. They compared conventional CPR (with mouth-to-mouth and chest compressions) with compression-only CPR. Over 40 000 patients were included.
Conventional CPR was associated with better outcomes than chest compression only CPR, for both one month survival (adjusted odds ratio 1.17, 95% confidence interval 1.06 to 1.29) and neurologically favourable one month survival (1.17, 1.01 to 1.35). Neurologically favourable one month survival decreased with increasing age and with delays of up to 10 minutes in starting CPR for both conventional and chest compression only CPR. The benefit of conventional CPR over chest compression only CPR was significantly greater in younger people in non-cardiac cases (P=0.025) and with a delay in start of CPR after the event was witnessed in non-cardiac cases (P=0.015) and all cases combined (P=0.037).
The authors conclude that conventional CPR is associated with better outcomes than chest compression only CPR for selected patients with out of hospital cardiopulmonary arrest, such as those with arrests of non-cardiac origin and younger people, and people in whom there was delay in the start of CPR.
Outcomes of chest compression only CPR versus conventional CPR conducted by lay people in patients with out of hospital cardiopulmonary arrest witnessed by bystanders: nationwide population based observational study
BMJ 2011; 2011; 342:c7106 Full Text

Improved survival with modified CPR

A large randomised controlled trial1 on out-of-hospital cardiac arrest patients compared standard CPR with CPR augmented by two modifications:

  • active compression-decompression using a hand-held suction device to compress the chest. The device is attached to the chest of the patient during CPR and the rescuer actively lifts the chest upwards after each compression, which are done at a rate of 80/min
  • augmented negative intrathoracic pressure using an impedance threshold device, which is a valve that limits passive air entry into the lungs during chest compressions, thereby reducing intrathoracic pressure and increasing blood flow to vital organs

The primary study endpoint was survival to hospital discharge with favourable neurological function.
Funding issues resulted in premature cessation of the study. 47 (6%) of 813 controls survived to hospital discharge with favourable neurological function compared with 75 (9%) of 840 patients in the intervention group (odds ratio 1·58, 95% CI 1·07–2·36; p=0·019]. 74 (9%) of 840 patients survived to 1 year in the intervention group compared with 48 (6%) of 813 controls (p=0·03), with equivalent cognitive skills, disability ratings, and emotional-psychological statuses in both groups. The overall major adverse event rate did not differ between groups, but more patients had pulmonary oedema in the intervention group (94 [11%] of 840) than did controls (62 [7%] of 813; p=0·015).
An accompanying editorial2 points out that previous studies in animal models of cardiac arrest gave reassuring results for both devices individually and when used together, but results from clinical trials in patients have been mixed for each device when used individually:

  • For compression-decompression CPR, a systematic review pooled the existing data for such CPR versus standard CPR in 4162 patients and found no difference in short-term mortality (relative risk 0·98, 95% CI 0·94–1·03) or survival to hospital discharge (0·99, 0·98–1·01). The 2010 CPR guidelines for the USA and Europe do not recommend the use of compression–decompression CPR alone.
  • The most current systematic review for the impedance-threshold device showed a significantly improved early survival (relative risk 1·45, 1·16–1·80), and a short-term improved neurological outcome (2·35, 1·30–4·24); however, improved long- term survival did not reach conventional statistical significance (1·48, 0·91–2·41).

The Resuscitation Outcomes Consortium (ROC) PRIMED study3 showed no survival benefit in 8718 patients randomised to standard CPR with an active or sham impedance-threshold device (the Consortium includes the same investigators as the Lancet paper). This was published as an abstract in Circulation recently.
The editorialist has reservations regarding a change in clinical practice resulting from this new study, partly because the trial was stopped prematurely and enrolment of a larger cohort could have changed the findings, and partly because the open use of both devices might have unintentionally introduced bias into the study. Further validation is recommended.
1. Standard cardiopulmonary resuscitation versus active compression-decompression cardiopulmonary resuscitation with augmentation of negative intrathoracic pressure for out-of-hospital cardiac arrest: a randomised trial
Lancet 2011;377:301-11
2. Augmented CPR: rescue after the ResQ trial
Lancet. 2011 Jan 22;377:276-7
3. The Resuscitation Outcomes Consortium ROC) PRIMED Impedance Threshold Device (ITD) Cardiac Arrest Trial: A Prospective, Randomized, Double-Blind, Controlled Clinical Trial
Circulation 2010; 122: 2215–26 (abstr)

LMA to stoma ventilation

Level 1 evidence is great, but for useful tips that can add options to your resuscitation toolbox there are some great finds in journal letters pages.
Try this one: An apneoic patient requires assisted ventilation in your resuscitation room. Bag-mask ventilation is ineffective. You then notice a mature tracheostomy at the same time that you’re told he had a laryngectomy. How would you ventilate him?
The obvious answer is to intubate the stoma with a size 6.0 tracheal tube or a tracheostomy tube if you have one. However prior to that you could bag-‘mask’ ventilate with a size 2 laryngeal mask airway applied to the stoma, holding the cuff in place with pressure through an index finger.

Such a technique is desribed in the context of an elective anaesthesia case in this month’s Anaesthesia. The LMA cuff provided an effective seal around the stoma, thereby allowing leak-free ventilation.
Stoma ventilation using a paediatric facemask is another option.

Tracheostomy ventilation using a laryngeal mask as a ‘bridge to extubation’
Anaesthesia 2010;65(12):1232–1233