‘Traditional’ rapid sequence induction of anaesthesia is often described with inclusion of cricoid pressure and the strict omission of any artifical ventilation between paralytic drug administration and insertion of the tracheal tube. These measures are aimed at preventing pulmonary aspiration of gastric contents although there is no convincing evidence base to support that. However it is known that cricoid pressure can worsen laryngoscopic view and can occlude the paediatric airway. We also know that children desaturate quickly after the onset of apnoea, and although apnoeic diffusion oxygenation via nasal cannula can prevent or delay that, in some cases it may be preferable to bag-mask ventilate the patient while awaiting full muscle relaxation for laryngoscopy.
A Swiss study looked at 1001 children undergoing RSI for non-cardiac surgery. They used a ‘controlled rapid sequence induction and intubation (cRSII)’ approach for children assumed to have full stomachs. This procedure resembled RSI the way it is currently done in many modern critical care settings, including the retrieval service I work for:
- No cricoid pressure
- Ketamine for induction if haemodynamically unstable
- A non-depolarising neuromuscular blocker rather than succinylcholine
- No cricoid pressure
- Gentle facemask ventilation to maintain oxygenation until intubation conditions achieved
- Intubation with a cuffed tracheal tube
- Still no cricoid pressure
The authors comment:
The main finding was that cRSII demonstrated a considerably lower incidence of oxygen desaturation and consecutive hemodynamic adverse events during anesthesia induction than shown by a previous study on classic RSII in children. Furthermore, there was no incidence of pulmonary aspiration during induction, laryngoscopy, and further course of anesthesia.
Looks like more dogma has been lysed, and this study supports the current trajectory away from traditional teaching towards an approach more suitable for critically ill patients.
Controlled rapid sequence induction and intubation – an analysis of 1001 children
Paediatr Anaesth. 2013 Aug;23(8):734-40
BACKGROUND: Classic rapid sequence induction puts pediatric patients at risk of cardiorespiratory deterioration and traumatic intubation due to their reduced apnea tolerance and related shortened intubation time. A ‘controlled’ rapid sequence induction and intubation technique (cRSII) with gentle facemask ventilation prior to intubation may be a safer and more appropriate approach in pediatric patients. The aim of this study was to analyze the benefits and complications of cRSII in a large cohort.
METHODS: Retrospective cohort analysis of all patients undergoing cRSII according to a standardized institutional protocol between 2007 and 2011 in a tertiary pediatric hospital. By means of an electronic patient data management system, vital sign data were reviewed for cardiorespiratory parameters, intubation conditions, general adverse respiratory events, and general anesthesia parameters.
RESULTS: A total of 1001 patients with cRSII were analyzed. Moderate hypoxemia (SpO2 80-89%) during cRSII occurred in 0.5% (n = 5) and severe hypoxemia (SpO2 <80%) in 0.3% of patients (n = 3). None of these patients developed bradycardia or hypotension. Overall, one single gastric regurgitation was observed (0.1%), but no pulmonary aspiration could be detected. Intubation was documented as ‘difficult’ in two patients with expected (0.2%) and in three patients with unexpected difficult intubation (0.3%). The further course of anesthesia as well as respiratory conditions after extubation did not reveal evidence of ‘silent aspiration’ during cRSII.
CONCLUSION: Controlled RSII with gentle facemask ventilation prior to intubation supports stable cardiorespiratory conditions for securing the airway in children with an expected or suspected full stomach. Pulmonary aspiration does not seem to be significantly increased.
After neonatal intubation, the incidence of malposition of the tip of the tracheal tube is fairly high.
A technique was evaluated involving palpation of the tube tip in the suprasternal notch, which in this small study was superior to insertion length based on a weight-based nomogram.
The suprasternal notch was chosen because it anatomically corresponds to vertebral level T2, close to the optimal position at the mid-tracheal point. Correct position on the chest radiograph was defined as any position <0.5 cm above the interclavicular midpoint and more than 1 cm above the carina.
During tracheal tube placement, the tip was gently palpated in the suprasternal notch with the index or little finger of the left hand while holding the body of the tube with the fingers of the right hand. The tube tip was adjusted until the bevelled edge was just palpable in the the suprasternal notch.
Digital palpation of endotracheal tube tip as a method of confirming endotracheal tube position in neonates: an open-label, three-armed randomized controlled trial.
Paediatr Anaesth. 2013 Oct;23(10):934-9
OBJECTIVE: To compare the malposition rates of endotracheal tubes (ETTs) when the insertional length (IL) is determined by a weight-based nomogram versus when IL is determined by palpation of the ETT tip.
DESIGN: Open-label, randomized controlled trial (RCT).
SETTING: Level III neonatal intensive care unit (NICU).
SUBJECTS: All newborn babies admitted in NICU requiring intubation.
INTERVENTIONS: Subjects were randomly allocated to one of three groups, wherein IL was determined by (i) weight-based nomogram alone, (ii) weight-based nomogram combined with suprasternal palpation of ETT tip performed by specially trained neonatology fellows, or (iii) combination of weight-based and suprasternal methods by personnel not specially trained.
PRIMARY OUTCOME: Rate of malposition of ETT as judged on chest X-ray (CXR).
RESULTS: Fifty seven babies were randomized into group 1(n = 15), group 2 (n = 20), and group 3 (n = 22). The proportion of correct ETT placement was highest in group 2, being 66.7%, 83.3%, and 66.7% in groups 1 through 3, respectively (P value = 0.58). No complication was attributable to palpation technique.
CONCLUSION: Suprasternal palpation shows promise as a simple, safe, and teachable method of confirming ETT position in neonates.
In some areas it has been traditional to pre-medicate or co-medicate with atropine when intubating infants and children, despite a lack of any evidence showing benefit. It is apparently still in the American Pediatric Advanced Life Support (PALS) Provider Manual when age is less than 1 year or age is 1–5 years and receiving succinylcholine. However it is not recommended with rapid sequence intubation in the British and Australasian Advanced Paediatric Life Support manual and course.
A French non-randomised observational study compares intubations with and without atropine in the neonatal and paediatric critical care setting. Atropine use was associated with significant acceleration of heart rate, and no atropine use was associated with a higher incidence of new dysrhythmia, the most common being junctional rhythm, but with none appearing to be clinically significant.
The incidence of the most important peri-intubation cause of bradycardia – hypoxia – is not reported. It is also not clear how many intubation attempts were required. The authors admit:
“it is not possible using our methodology to deduce whether bradycardia was due to hypoxia, laryngoscopy, or sedation drugs.“
Actual rapid sequence was rarely employed – their use of muscle relaxants was low – making this difficult to extrapolate to modern emergency medicine / critical care practice.
My take home message here is that this study provides no argument whatsoever for the addition of atropine in routine RSI in the critically ill child. Why complicate a procedure with an unnecessary tachycardia-causing drug when the focus should be on no desat / no hypotension / first look laryngoscopy?
The Effect of Atropine on Rhythm and Conduction Disturbances During 322 Critical Care Intubations
Pediatr Crit Care Med. 2013 Jul;14(6):e289-97
OBJECTIVES: Our objectives were to describe the prevalence of arrhythmia and conduction abnormalities before critical care intubation and to test the hypothesis that atropine had no effect on their prevalence during intubation.
DESIGN: Prospective, observational study.
SETTING: PICU and pediatric/neonatal intensive care transport.
SUBJECTS: All children of age less than 8 years intubated September 2007-2009. Subgroups of intubations with and without atropine were analyzed.
MEASUREMENT AND MAIN RESULTS: A total of 414 intubations were performed in the study period of which 327 were available for analysis (79%). Five children (1.5%) had arrhythmias prior to intubation and were excluded from the atropine analysis. Atropine was used in 47% (152/322) of intubations and resulted in significant acceleration of heart rate without provoking ventricular arrhythmias. New arrhythmias during intubation were related to bradycardia and were less common with atropine use (odds ratio, 0.14 [95% CI, 0.06-0.35], p < 0.001). The most common new arrhythmia was junctional rhythm. Acute bundle branch block was observed during three intubations; one Mobitz type 2 rhythm and five ventricular escape rhythms occurred in the no-atropine group (n = 170). Only one ventricular escape rhythm occurred in the atropine group (n = 152) in a child with an abnormal heart. One child died during intubation who had not received atropine.
CONCLUSIONS: Atropine significantly reduced the prevalence of new arrhythmias during intubation particularly for children over 1 month of age, did not convert sinus tachycardia to ventricular tachycardia or fibrillation, and may contribute to the safety of intubation.
A paediatric trauma centre study showed that in their system, seven people at the bedside was the optimum number to get tasks done in a paediatric resuscitation. As numbers increased beyond this, there were ‘diminishing marginal returns’, ie. the output (tasks completed) generated from an additional unit of input (extra people) decreases as the quantity of the input rises.
The authors comment that after a saturation point is reached, “additional team members contribute negative returns, resulting in fewer tasks completed by teams with the most members. This pattern has been demonstrated in other medical groups, with larger surgical teams having prolonged operative times and larger paramedic crews delaying the performance of cardiopulmonary resuscitation.“
There are several possible explanations:
- crowding limits access to the patient or equipment;
- “social loafing”- staff may feel less accountable for the overall group performance and less pressure to accomplish individual tasks;
- seven is the number recommended in that institution’s trauma activation protocol, with optimal role allocation described for a team of that size;
- teams with redundant personnel may experience role confusion and fragmentation, resulting in both repetition and omission of tasks.
In my view, excessive team size results in there being more individuals to supervise & monitor, and hence a greater cognitive load for the team leader (cue the resus safety officer). More crowding and obstruction threatens situational awareness. There is more difficulty in providing clear uninterrupted closed loop communication. And general resuscitation room entropy increases, requiring more energy to contain or reverse it.
However, for paediatric resuscitations requiring optimal concurrent activity to progress the resuscitation, I do struggle with less than five. Unless of course I’m in my HEMS role, when the paramedic and I just crack on.
More on Making Things Happen in resus.
Own The Resus talk
Resus Room Management site
Factors Affecting Team Size and Task Performance in Pediatric Trauma Resuscitation.
Pediatr Emerg Care. 2014 Mar 19. [Epub ahead of print]
OBJECTIVES: Varying team size based on anticipated injury acuity is a common method for limiting personnel during trauma resuscitation. While missing personnel may delay treatment, large teams may worsen care through role confusion and interference. This study investigates factors associated with varying team size and task completion during trauma resuscitation.
METHODS: Video-recorded resuscitations of pediatric trauma patients (n = 201) were reviewed for team size (bedside and total) and completion of 24 resuscitation tasks. Additional patient characteristics were abstracted from our trauma registry. Linear regression was used to assess which characteristics were associated with varying team size and task completion. Task completion was then analyzed in relation to team size using best-fit curves.
RESULTS: The average bedside team ranged from 2.7 to 10.0 members (mean, 6.5 [SD, 1.7]), with 4.3 to 17.7 (mean, 11.0 [SD, 2.8]) people total. More people were present during high-acuity activations (+4.9, P < 0.001) and for patients with a penetrating injury (+2.3, P = 0.002). Fewer people were present during activations without prearrival notification (-4.77, P < 0.001) and at night (-1.25, P = 0.002). Task completion in the first 2 minutes ranged from 4 to 19 (mean, 11.7 [SD, 3.8]). The maximum number of tasks was performed at our hospital by teams with 7 people at the bedside (13 total).
CONCLUSIONS: Resuscitation task completion varies by team size, with a nonlinear association between number of team members and completed tasks. Management of team size during high-acuity activations, those without prior notification, and those in which the patient has a penetrating injury may help optimize performance.
High Flow Nasal Cannulae (HFNC) oxygen therapy was introduced in paediatric interfacility retrievals undertaken by the Mater Children’s PICU Retrieval Team in Queensland, Australia. In 793 under 2 year olds, HFNC was associated with a reduction in infants receiving invasive or non-invasive ventilation. 77% of the patients had bronchiolitis.
The rationale for this treatment is explained as:
Owing to the inherent properties of the infant respiratory system with small airways and high chest compliance, the risk of developing atelectasis is high in bronchiolitis. HFNC therapy applied early in the disease process may prevent progression of the disease and maintain normal lung volumes, thereby preventing atelectasis. As a result, the functional residual capacity can be maintained and work of breathing reduced, which may stabilize the patient sufﬁciently to avoid the need for intubation. For this purpose we used ﬂow rates of 2 L/kg/min which have been shown to result in a positive end-expiratory pressure of 4–5 cmH2O
Read more on high-ﬂow nasal cannula oxygen therapy.
High-ﬂow nasal cannula (HFNC) support in interhospital transport of critically ill children
Intensive Care Med. 2014 Feb 15. [Epub ahead of print]
BACKGROUND: Optimal respiratory support for interhospital transport of critically ill children is challenging and has been scarcely investigated. High-flow nasal cannula (HFNC) therapy has emerged as a promising support mode in the paediatric intensive care unit (PICU), but no data are available on HFNC used during interhospital transport. We aimed to assess the safety of HFNC during retrievals of critically ill children and its impact on the need for invasive ventilation (IV).
METHODS: This was a retrospective, single-centre study of children under 2 years old transported by a specialized paediatric retrieval team to PICU. We compared IV rates before (2005-2008) and after introduction of HFNC therapy (2009-2012).
RESULTS: A total of 793 infants were transported. The mean transport duration was 1.4 h (range 0.25-8), with a mean distance of 205 km (2-2,856). Before introduction of HFNC, 7 % (n = 23) were retrieved on non-invasive ventilation (NIV) and 49 % (n = 163) on IV. After introduction of HFNC, 33 % (n = 150) were retrieved on HFNC, 2 % (n = 10) on NIV, whereas IV decreased to 35 % (n = 162, p < 0.001). No patients retrieved on HFNC required intubation during retrieval, or developed pneumothorax or cardiac arrest. Using HFNC was associated with a significant reduction in IV initiated by the retrieval team (multivariate OR 0.51; 95 % CI 0.27-0.95; p = 0.032).
CONCLUSIONS: We report on a major change of practice in transport of critically ill children in our retrieval system. HFNC therapy was increasingly used and was not inferior to low-flow oxygen or NIV. Randomized trials are needed to assess whether HFNC can reduce the need for IV in interhospital transport of critically ill children.
In the absence of vascular access we may resort to sending intraosseous aspirates for analysis, but in some laboratories there is concern that the samples can block autoanalysers.
A study on haematology/oncology patients undergoing diagnostic bone marrow aspiration showed clinically acceptable agreement between venous and intraosseous measurements for pH, base excess, sodium, ionised calcium and glucose using an an i-STAT® point-of-care analyser.
Key points are:
- The first 1-2 ml should be discarded (as in this study)
- Lactate hasn’t been assessed
- These patients weren’t critically ill
Analysis of bloodgas, electrolytes and glucose from intraosseous samples using an i-STAT® point-of-care analyser
Resuscitation. 2014 Mar;85(3):359-63
BACKGROUND: Intraosseous access is used in emergency medicine as an alternative when intravenous access is difficult to obtain. Intraosseous samples can be used for laboratory testing to guide treatment. Many laboratories are reluctant to analyse intraosseous samples, as they frequently block conventional laboratory equipment. We aimed to evaluate the feasibility and accuracy of analysis of intraosseous samples using an i-STAT(®) point-of-care analyser.
METHODS: Intravenous and intraosseous samples of twenty children presenting for scheduled diagnostic bone marrow aspiration were analysed using an i-STAT(®) point-of-care analyser. Sample types were compared using Bland Altman plots and by calculating intraclass correlation coefficients and coefficients of variance.
RESULTS: The handheld i-STAT(®)point-of-care analyser proved suitable for analysing intraosseous samples without technical difficulties. Differences between venous and intraosseous samples were clinically acceptable for pH, base excess, sodium, ionised calcium and glucose in these haemodynamically stable patients. The intraclass correlation coefficient was excellent (>0.8) for comparison of intraosseous and intravenous base excess, and moderate (around 0.6) for bicarbonate, sodium and glucose. The coefficient of variance of intraosseous samples was smaller than that of venous samples for most variables.
CONCLUSION: Analysis of intraosseous samples with a bedside, single-use cartridge-based analyser is feasible and avoids the problem of bone marrow contents damaging conventional laboratory equipment. In an emergency situation point-of-care analysis of intraosseous aspirates may be a useful guide to treatment.
Researchers from the Iberian-American Paediatric Cardiac Arrest Study Network challenge the evidence base behind defibrillation shock dose recommendations in children.
In a study of in-hospital pediatric cardiac arrest due to VT or VF, clinical outcome was not related to the cause or location of arrest, type of defibrillator and waveform, energy dose per shock, number of shocks, or cumulative energy dose, although there was a trend to better survival with higher doses per shock. 50% of children required more than the recommended 4J per kg and in over a quarter three or more shocks were needed to achieve defibrillation.
Shockable rhythms and defibrillation during in-hospital pediatric cardiac arrest
Resuscitation. 2014 Mar;85(3):387-91
OBJECTIVE: To analyze the results of cardiopulmonary resuscitation (CPR) that included defibrillation during in-hospital cardiac arrest (IH-CA) in children.
METHODS: A prospective multicenter, international, observational study on pediatric IH-CA in 12 European and Latin American countries, during 24 months. Data from 502 children between 1 month and 18 years were collected using the Utstein template. Patients with a shockable rhythm that was treated by electric shock(s) were included. The primary endpoint was survival at hospital discharge. Univariate logistic regression analysis was performed to find outcome factors.
RESULTS: Forty events in 37 children (mean age 48 months, IQR: 7-15 months) were analyzed. An underlying disease was present in 81.1% of cases and 24.3% had a previous CA. The main cause of arrest was a cardiac disease (56.8%). In 17 episodes (42.5%) ventricular fibrillation (VF) or pulseless ventricular tachycardia (pVT) was the first documented rhythm, and in 23 (57.5%) it developed during CPR efforts. In 11 patients (27.5%) three or more shocks were needed to achieve defibrillation. Return of spontaneous circulation (ROSC) was obtained in 25 cases (62.5%), that was sustained in 20 (50.0%); however only 12 children (32.4%) survived to hospital discharge. Children with VF/pVT as first documented rhythm had better sustained ROSC (64.7% vs. 39.1%, p=0.046) and survival to hospital discharge rates (58.8% vs. 21.7%, p=0.02) than those with subsequent VF/pVT. Survival rate was inversely related to duration of CPR. Clinical outcome was not related to the cause or location of arrest, type of defibrillator and waveform, energy dose per shock, number of shocks, or cumulative energy dose, although there was a trend to better survival with higher doses per shock (25.0% with <2Jkg(-1), 43.4% with 2-4Jkg(-1) and 50.0% with >4Jkg(-1)) and worse with higher number of shocks and cumulative energy dose.
CONCLUSION: The termination of pediatric VF/pVT in the IH-CA setting is achieved in a low percentage of instances with one electrical shock at 4Jkg(-1). When VF/pVT is the first documented rhythm, the results of defibrillation are better than in the case of subsequent VF/pVT. No clear relationship between defibrillation protocol and ROSC or survival has been observed. The optimal pediatric defibrillation dose remains to be determined; therefore current resuscitation guidelines cannot be considered evidence-based, and additional research is needed.
The observation that patients with haemorrhagic trauma in military and civilian settings do better if they receive coagulation factors and platelets is yet to be replicated in a randomised trial. It has been suggested that the effect may in part be a consequence of survivor bias – ie. that if a patient lives long enough to received some thawed fresh frozen plasma, then they were already more likely to be a survivor and therefore more survivors will be represented in the ‘FFP’ groups vs a ‘no-FFP’ comparison group.
An attempt to eliminate survivor bias was made in the PROMMTT study, which documented the timing of transfusions during active resuscitation and patient outcomes in adult trauma patients who received a transfusion of at least 1 unit of RBCs within 6 hours of admission.
Increased ratios of plasma:RBCs and platelets:RBCs were independently associated with decreased 6-hour mortality, when haemorrhagic death predominated. In the first 6 hours, patients with ratios less than 1:2 were 3 to 4 times more likely to die than patients with ratios of 1:1 or higher.
A prospective trial is underway to identify the optimal ratio of blood products, in the PROPPR study, in which 1:1:1 ratio of plasma:platelets:RBC will be compared with 1:1:2.
The Prospective, Observational, Multicenter, Major Trauma Transfusion (PROMMTT) Study
Arch Surg. 2012 Oct 15:1-10
Objective: To relate in-hospital mortality to early transfusion of plasma and/or platelets and to time-varying plasma:red blood cell (RBC) and platelet:RBC ratios.
Design: Prospective cohort study documenting the timing of transfusions during active resuscitation and patient outcomes. Data were analyzed using time-dependent proportional hazards models.
Setting: Ten US level I trauma centers.
Patients: Adult trauma patients surviving for 30 minutes after admission who received a transfusion of at least 1 unit of RBCs within 6 hours of admission (n = 1245, the original study group) and at least 3 total units (of RBCs, plasma, or platelets) within 24 hours (n = 905, the analysis group).
Main Outcome Measure: In-hospital mortality.
Results: Plasma:RBC and platelet:RBC ratios were not constant during the first 24 hours (P < .001 for both). In a multivariable time-dependent Cox model, increased ratios of plasma:RBCs (adjusted hazard ratio = 0.31; 95% CI, 0.16-0.58) and platelets:RBCs (adjusted hazard ratio = 0.55; 95% CI, 0.31-0.98) were independently associated with decreased 6-hour mortality, when hemorrhagic death predominated. In the first 6 hours, patients with ratios less than 1:2 were 3 to 4 times more likely to die than patients with ratios of 1:1 or higher. After 24 hours, plasma and platelet ratios were unassociated with mortality, when competing risks from nonhemorrhagic causes prevailed.
Conclusions: Higher plasma and platelet ratios early in resuscitation were associated with decreased mortality in patients who received transfusions of at least 3 units of blood products during the first 24 hours after admission. Among survivors at 24 hours, the subsequent risk of death by day 30 was not associated with plasma or platelet ratios.
A recent study showed superior effectiveness of one bag-mask ventilation style over another in novice providers. The technique recommended is the thenar eminence grip, in which downward pressure is applied with the thenar eminences while the four fingers of each hand pull the jaw upwards toward the mask.
Interestingly, in their crossover study in which the thenar emininence (TE) technique was compared with the traditionally taught ‘CE’ technique, they demonstrated a ‘sequence effect’. If subjects did TE first, they maintained good tidal volumes when doing CE. However if they did CE first, they achieved poor tidal volumes which were markedly improved when switching to TE.
The authors suggest: “A possible explanation for this sequence effect is that the TE grip is superior. When one used the TE grip first, he or she was more likely to learn how a good tidal volume “feels” and then more likely to apply good technique with the EC grip.“.
Some of us have been practicing and teaching this technique for a while. None have put it better than the brilliant Reuben Strayer of EM Updates in this excellent short video:
Emergency Ventilation in 11 Minutes from reuben strayer on Vimeo.
Efficacy of facemask ventilation techniques in novice providers
J Clin Anesth. 2013 May;25(3):193-7
STUDY OBJECTIVE: To determine which of two facemask grip techniques for two-person facemask ventilation was more effective in novice clinicians, the traditional E-C clamp (EC) grip or a thenar eminence (TE) technique.
DESIGN: Prospective, randomized, crossover comparison study.
SETTING: Operating room of a university hospital.
SUBJECTS: 60 novice clinicians (medical and paramedic students).
MEASUREMENTS: Subjects were assigned to perform, in a random order, each of the two mask-grip techniques on consenting ASA physical status 1, 2, and 3 patients undergoing elective general anesthesia while the ventilator delivered a fixed 500 mL tidal volume (VT). In a crossover manner, subjects performed each facemask ventilation technique (EC and TE) for one minute (12 breaths/min). The primary outcome was the mean expired VT compared between techniques. As a secondary outcome, we examined mean peak inspiratory pressure (PIP).
MAIN RESULTS: The TE grip provided greater expired VT (379 mL vs 269 mL), with a mean difference of 110 mL (P < 0.0001; 95% CI: 65, 157). Using the EC grip first had an average VT improvement of 200 mL after crossover to the TE grip (95% CI: 134, 267). When the TE grip was used first, mean VTs were greater than for EC by 24 mL (95% CI: -25, 74). When considering only the first 12 breaths delivered (prior to crossover), the TE grip resulted in mean VTs of 339 mL vs 221 mL for the EC grip (P = 0.0128; 95% CI: 26, 209). There was no significant difference in PIP values using the two grips: the TE mean (SD) was 14.2 (7.0) cm H2O, and the EC mean (SD) was 13.5 (9.0) cm H2O (P = 0.49).
CONCLUSIONS: The TE facemask ventilation grip results in improved ventilation over the EC grip in the hands of novice providers.
The noxious stimulus of laryngoscopy & tracheal intubation can precipitate hypertension, tachycardia, and intracranial pressure elevation, risking exacerbation of brain injury or haemorrhage. Physicians from an English Helicopter Emergency Medical Service examined the response of heart rate and blood pressure to prehospital rapid sequence intubation (RSI). While a retrospective study, the haemodynamic data were prospectively recorded and documented using standard monitor printouts, and time of intubation could be accurately determined by the onset of capnography recordings. Their standardised system documents blood pressure recordings every three minutes. Etomidate and suxamethonium were used for RSI.
They report their findings:
A hypertensive response occurred in 79% (70/89) of patients. MAP exceeded the upper limit of estimated intact cerebral autoregulation (150 mmHg) in 18% (16/89) of cases and 9% (8/89) of patients had a greater than 100% increase in MAP and/or SBP. A single hypotensive response occurred. A tachycardic response occurred in 58% (64/110) of patients and bradycardia was induced in one.
Of note, 97 of the 115 patients had injuries that included head trauma.
The authors note that opioids are often co-administered during in-hospital RSI and that this may offset the haemodynamic stimulation, while possible increasing the complexity of the procedure in the prehospital environment. They have modified their pre-hospital anaesthesia standard operating procedure to include the use of an opioid and will report the associated outcomes and complication rates ‘in due course’.
This is interesting and important stuff, and something we should all be looking at in our respective prehospital critical care services.
The haemodynamic response to pre-hospital RSI in injured patients
Injury. 2013 May;44(5):618-23
BACKGROUND: Laryngoscopy and tracheal intubation provoke a marked sympathetic response, potentially harmful in patients with cerebral or cardiovascular pathology or haemorrhage. Standard pre-hospital rapid sequence induction of anaesthesia (RSI) does not incorporate agents that attenuate this response. It is not known if a clinically significant response occurs following pre-hospital RSI or what proportion of injured patients requiring the intervention are potentially at risk in this setting.
METHODS: We performed a retrospective analysis of 115 consecutive pre-hospital RSI’s performed on trauma patients in a physician-led Helicopter Emergency Medical Service. Primary outcome was the acute haemodynamic response to the procedure. A clinically significant response was defined as a greater than 20% change from baseline recordings during laryngoscopy and intubation.
RESULTS: Laryngoscopy and intubation provoked a hypertensive response in 79% of cases. Almost one-in-ten patients experienced a greater than 100% increase in mean arterial pressure (MAP) and/or systolic blood pressure (SBP). The mean (95% CI) increase in SBP was 41(31-51) mmHg and MAP was 30(23-37) mmHg. Conditions leaving the patient vulnerable to secondary injury from a hypertensive response were common.
CONCLUSIONS: Laryngoscopy and tracheal intubation, following a standard pre-hospital RSI, commonly induced a clinically significant hypertensive response in the trauma patients studied. We believe that, although this technique is effective in securing the pre-hospital trauma airway, it is poor at attenuating adverse physiological effects that may be detrimental in this patient group.