The ability of paramedics to predict aspiration in patients undergoing prehospital rapid sequence intubation

Rapid Sequence Intubation Using the SEADUC Manual Suction Unit in a Contaminated Airway

The case presented here highlights the utility/feasibility of the SEADUC (EM Innovations, Galloway, OH) manual suction unit in clearing a contaminated airway during rapid sequence intubation. The case also highlights the importance of intubation in a patient with declining mental status in the prehospital environment. A 75-year-old woman suffered a head injury, and a helicopter emergency medical service team staffed with a physician and nurse was tasked with retrieval and transfer back to the tertiary care center. As the flight team rendezvoused with ground emergency medical services and the patient, a decision to intubate was made because of the patient's declining mental status and inability to protect her own airway. While in preparation for intubation, it was noted that the ambulance's electrical suction system was not working, and the flight crew had to resort to a SEADUC manual suction unit to clear the patient's airway of contaminants. The patient's airway was cleared, and she was successfully intubated and transported to a tertiary care center where the patient underwent an emergent neurosurgery procedure/decompression and was discharged home a few weeks later.

Aspiration risk in relation to Glasgow Coma Scale score and clinical parameters in patients with severe acute alcohol intoxication: a single-centre, retrospective study

OBJECTIVES

In alcohol intoxicated patients, the decision for or against airway protection can be challenging and is often based on the Glasgow Coma Scale (GCS). Primary aim of this study was to analyse the aspiration risk in relation to the GCS score and clinical parameters in patients with severe acute alcohol monointoxication. Secondary aim was the association between the blood alcohol level and the GCS score.

SETTING

Single-centre, retrospective study of alcoholised patients admitted to a German intensive care unit between 2006 and 2020.

PARTICIPANTS

A total of n=411 admissions were eligible for our analysis.

CLINICAL MEASURES AND ANALYSIS

The following data were extracted: age, gender, admission time, blood alcohol level, blood glucose level, initial GCS score, GCS score at admission, vital signs, clinical signs of aspiration and airway management measures. The empirical distribution of continuous and categorical data was calculated. Binary multivariable logistic regression analysis was used to identify possible risk factors for aspiration.

RESULTS

The mean age was 35 years. 72% (n=294) of the admissions were male. The blood alcohol level (mean 2.7 g/L±1.0, maximum 5.9 g/L) did not correlate with the GCS score but with the age of the patient. In univariate analysis, the aspiration risk correlated with blood alcohol level, age, GCS score, oxygen saturation, respiratory rate and blood glucose level and was significantly higher in male patients, on vomiting, and in patients requiring airway measures. Aspiration rate was 45% (n=10) in patients without vs 6% (n=3) in patients with preserved protective reflexes (p=0.0001). In the multivariate analysis, only age and GCS score were significantly associated with the risk of aspiration.

CONCLUSION

Although in this single-centre, retrospective study the aspiration rate in severe acute alcohol monointoxicated patients correlates with GCS and protective reflexes, the decision for endotracheal intubation might rather be based on the presence of different risk factors for aspiration.

The success of pre-hospital tracheal intubation by different pre-hospital providers: a systematic literature review and meta-analysis

BACKGROUND

Pre-hospital basic airway interventions can be ineffective at providing adequate oxygenation and ventilation in some severely ill or injured patients, and advanced airway interventions are then required. Controversy exists regarding the level of provider required to perform successful pre-hospital intubation. A previous meta-analysis reported pre-hospital intubation success rates of 0.849 for non-physicians versus 0.991 for physicians. The evidence base on the topic has expanded significantly in the last 10 years. This study systematically reviewed recent literature and presents comprehensive data on intubation success rates.

METHODS

A systematic search of MEDLINE and EMBASE was performed using PRISMA methodology to identify articles on pre-hospital tracheal intubation published between 2006 and 2016. Overall success rates were estimated using random effects meta-analysis. The relationship between intubation success rate and provider type was assessed in weighted linear regression analysis.

RESULTS

Of the 1838 identified studies, 38 met the study inclusion criteria. Intubation was performed by non-physicians in half of the studies and by physicians in the other half. The crude median (range) reported overall success rate was 0.969 (0.616-1.000). In random effects meta-analysis, the estimated overall intubation success rate was 0.953 (0.938-0.965). The crude median (range) reported intubation success rates for non-physicians were 0.917 (0.616-1.000) and, for physicians, were 0.988 (0.781-1.000) (p = 0.003).

DISCUSSION

The reported overall success rate of pre-hospital intubation has improved, yet there is still a significant difference between non-physician and physician providers. The finding that less-experienced personnel perform less well is not unexpected, but since there is considerable evidence that poorly performed intubation carries a significant risk of morbidity and mortality careful consideration should be given to the training and experience required to deliver this intervention safely.

A Comparison of Invasive Airway Management and Rates of Pneumonia in Prehospital and Hospital Settings

INTRODUCTION

Infection is a major cause of morbidity and mortality in trauma. Infection in trauma is poorly understood. The impact of prehospital invasive airway management (IAM) on the incidence of pneumonia and health services utilization is unknown. We hypothesized that trauma patients exposed to prehospital IAM will suffer higher rates of pneumonia compared to no IAM or exposure to IAM performed in the hospital. We hypothesized that patients who develop pneumonia subsequent to prehospital IAM will have longer intensive care unit (ICU) and hospital length of stay (LOS) compared to patients who acquired pneumonia after IAM performed in the hospital.

METHODS

This is an observational cohort study of data previously collected for the Resuscitation Outcomes Consortium hypertonic resuscitation randomized trial. Patients were included if traumatic injury resulted in shock, traumatic brain injury, or both. Patients were excluded if they died 24 hours after injury, or pneumonia data were missing. Adjusted and unadjusted logistic regression was used to calculate the odds ratio of pneumonia if exposed in the prehospital setting compared to no exposure or exposure in the hospital.

RESULTS

Of 2,222 patients enrolled in the hypertonic resuscitation trial, 1,676 patients met enrollment criteria for this study. Four and a half percent of patients suffered pneumonia. IAM in the prehospital setting resulted in 6.8-fold increase (C.I. 2.0, 23.0, p = 0.003) in the adjusted odds of developing pneumonia compared to not being intubated, while in-hospital intubation resulted in 4.8-fold increase (C.I. 1.4, 16.6, p = 0.01), which was not statistically significantly different to the odds ratio of prehospital IAM. There were no statistically significant increases in health services utilization resulting from pneumonia incurred after IAM.

CONCLUSION

Exposure to IAM in prehospital and hospital settings results in an increase in pneumonia, but there does not appear to be a link between the source of pneumonia and an increase in ICU or hospital LOS.

Perioperative hypoxemia is common with horizontal positioning during general anesthesia and is associated with major adverse outcomes: a retrospective study of consecutive patients

Background

Reported perioperative pulmonary aspiration (POPA) rates have substantial variation. Perioperative hypoxemia (POH), a manifestation of POPA, has been infrequently studied beyond the PACU, for patients undergoing a diverse array of surgical procedures.

Methods

Consecutive adult patients with ASA I-IV and pre-operative pulmonary stability who underwent a surgical procedure requiring general anesthesia were investigated. Using pulse oximetry, POH was documented in the operating room and during the 48 hours following PACU discharge. POPA was the presence of an acute pulmonary infiltrate with POH.

Results

The 500 consecutive, eligible patients had operative body-positions of prone 13%, decubitus 8%, sitting 1%, and supine/lithotomy 78%, with standard practice of horizontal recumbency. POH was found in 150 (30%) patients. Post-operative stay with POH was 3.7 ± 4.7 days and without POH was 1.7 ± 2.3 days (p < 0.0001). POH rate varied from 14% to 58% among 11 of 12 operative procedure-categories. Conditions independently associated with POH (p < 0.05) were acute trauma, BMI, ASA level, glycopyrrolate administration, and duration of surgery. POPA occurred in 24 (4.8%) patients with higher mortality (8.3%), when compared to no POPA (0.2%; p = 0.0065). Post-operative stay was greater with POPA (7.7 ± 5.7 days), when compared to no POPA (2.0 ± 2.9 days; p = 0.0001). Conditions independently associated with POPA (p < 0.05) were cranial procedure, ASA level, and duration of surgery. POPA, acute trauma, duration of surgery, and inability to extubate in the OR were independently associated with post-operative stay (p < 0.05). POH, gastric dysmotility, acute trauma, cranial procedure, emergency procedure, and duration of surgery had independent correlations with post-operative length of stay (p < 0.05).

Conclusions

Adult surgical patients undergoing general anesthesia with horizontal recumbency have substantial POH and POPA rates. Hospital mortality was greater with POPA and post-operative stay was increased for POH and POPA. POH rates were noteworthy for virtually all categories of operative procedures and POH and POPA were independent predictors of post-operative length of stay. A study is needed to determine if modest reverse-Trendelenburg positioning during general anesthesia has a relationship with reduced POH and POPA rates.

Prehospital intubation in patients with isolated severe traumatic brain injury: a 4-year observational study

Objectives. To study the effect of prehospital intubation (PHI) on survival of patients with isolated severe traumatic brain injury (ISTBI). Method. Retrospective analyses of all intubated patients with ISTBI between 2008 and 2011 were studied. Comparison was made between those who were intubated in the PHI versus in the trauma resuscitation unit (TRU). Results. Among 1665 TBI patients, 160 met the inclusion criteria (105 underwent PHI, and 55 patients were intubated in TRU). PHI group was younger in age and had lower median scene motor GCS (P = 0.001). Ventilator days and hospital length of stay (P = 0.01 and 0.006, resp.) were higher in TRUI group. Mean ISS, length of stay, initial blood pressure, pneumonia, and ARDS were comparable among the two groups. Mortality rate was higher in the PHI group (54% versus 31%, P = 0.005). On multivariate regression analysis, scene motor GCS (OR 0.55; 95% CI 0.41-0.73) was an independent predictor for mortality. Conclusion. PHI did not offer survival benefit in our group of patients with ISTBI based on the head AIS and the scene motor GCS. However, more studies are warranted to prove this finding and identify patients who may benefit from this intervention.

Prehospital risk factors of mortality and impaired consciousness after severe traumatic brain injury: an epidemiological study

Background

Severe traumatic brain injury (TBI) is a significant health concern and a major burden for society. The period between trauma event and hospital admission in an emergency department (ED) could be a determinant for secondary brain injury and early survival. The aim was to investigate the relationship between prehospital factors associated with secondary brain injury (arterial hypotension, hypoxemia, hypothermia) and the outcomes of mortality and impaired consciousness of survivors at 14 days.

Methods

A multicenter, prospective cohort study was performed in dedicated trauma centres of Switzerland. Adults with severe TBI (Abbreviated Injury Scale score of head region (HAIS) >3) were included. Main outcome measures were death and impaired consciousness (Glasgow Coma Scale (GCS) ≤13) at 14 days. The associations between risk factors and outcome were assessed with univariate and multivariate regression models.

Results

589 patients were included, median age was 55 years (IQR 33, 70). The median GCS in ED was 4 (IQR 3-14), with abnormal pupil reaction in 167 patients (29.2%). Median ISS was 25 (IQR 21, 34). Three hundred seven patients sustained their TBI from falls (52.1%) and 190 from a road traffic accidents (32.3%). Median time from Out-of-hospital Emergency Medical Service (OHEMS) departure on scene to arrival in ED was 50 minutes (IQR 37-72); 451 patients had a direct admission (76.6%). Prehospital hypotension was observed in 24 (4.1%) patients, hypoxemia in 73 (12.6%) patients and hypothermia in 146 (24.8%). Prehospital hypotension and hypothermia (apart of age and trauma severity) was associated with mortality. Prehospital hypoxemia (apart of trauma severity) was associated with impaired consciousness; indirect admission was a protective factor.

Conclusion

Mortality and impaired consciousness at 14 days do not have the same prehospital risk factors; prehospital hypotension and hypothermia is associated with mortality, and prehospital hypoxemia with impaired consciousness.

Supraglottic airway device use as a primary airway during rapid sequence intubation

INTRODUCTION

This study compared first-attempt placement success rates of the King LTS-D as a primary airway for patients requiring medication-assisted airway management (MAAM) against historical controls.

SETTING

Rotor-wing division of a single critical care transportation company

METHODS

53 providers (RNs/EMT-P) consented to participation and were trained in the use of the King LTS-D. All patients in need of MAAM per agency treatment guidelines were screened for inclusion and exclusion criteria. After each placement attempt, providers completed data collection via telephone. The primary endpoint was comparison of first-attempt placement success rate between the King LTS-D and historical control endotracheal intubation (ETI) MAAM patients. Overall placement success, time to placement, pre- and post-placement SaO2, ETCO2 at 2 minutes after placement, and complications were also analyzed.

RESULTS

38 patients received rapid sequence intubation with the King LTS-D by 23 of 58 consented providers. First-attempt success rate was 76% (29/38), with an overall success rate of 84% (32/38). The primary endpoint analysis showed no difference in first-attempt success rate between historical control ETI MAAM data and King LTS-D (71% vs 76%; OR = 0.1.34 [95% CI Intubation time to insertion was 26 seconds (IQR = 12-46). Pre- and post-insertion SaO(1)2 values were 88.9 ± 12.6% and 92.1 ± 12.7%, respectively. Mean ETCO2 at 2 minutes after placement was 34.8 ± 4.0. Vomit in the patient's airway was the most frequently reported complication (46%).

CONCLUSION

Success rates with the King LTS-D were not significantly different from historical control ETI data. Time to placement was comparable to previous reports.

Increased risk of pneumonia among ventilated patients with traumatic brain injury: every day counts!

BACKGROUND

Patients with traumatic brain injury (TBI) frequently require mechanical ventilation (MV). The objective of this study was to examine the association between time spent on MV and the development of pneumonia among patients with TBI.

MATERIALS AND METHODS

Patients older than 18 y with head abbreviated injury scale (AIS) scores coded 1-6 requiring MV in the National Trauma Data Bank 2007-2010 data set were included. The study was limited to hospitals reporting pneumonia cases. AIS scores were calculated using ICDMAP-90 software. Patients with injuries in any other region with AIS score >3, significant burns, or a hospital length of stay >30 d were excluded. A generalized linear model was used to determine the approximate relative risk of developing all-cause pneumonia (aspiration pneumonia, ventilator-associated pneumonia [VAP], and infectious pneumonia identified by the International Classification of Disease, Ninth Revision, diagnosis code) for each day of MV, controlling for age, gender, Glasgow coma scale motor score, comorbidity (Charlson comorbidity index) score, insurance status, and injury type and severity.

RESULTS

Among the 24,525 patients with TBI who required MV included in this study, 1593 (6.5%) developed all-cause pneumonia. After controlling for demographic and injury factors, each additional day on the ventilator was associated with a 7% increase in the risk of pneumonia (risk ratio 1.07, 95% confidence interval 1.07-1.08).

CONCLUSIONS

Patients who have sustained TBIs and require MV are at higher risk for VAP than individuals extubated earlier; therefore, shortening MV exposure will likely reduce the risk of VAP. As patients with TBI frequently require MV because of neurologic impairment, it is key to develop aggressive strategies to expedite ventilator independence.

Research priorities in neurocritical care

This summary of the last session of the First Neurocritical Care Research Conference reviews the discussions about research priorities in neurocritical care. The first presentation reviewed current projects funded by the National Institute of Neurological Disorders and Stroke at the National Institutes of Health and potential models to follow including an independent Neurocritical Care Network or the creation of such a network with the goal of collaborating with already existing ones. Experienced neurointensivists then presented their views on the most common and important research questions that need to be answered and investigated in the field. Finally, utility of clinical registries was discussed emphasizing their importance as hypothesis generators. During the group discussion, interests in comparative effectiveness research, the use of physiological endpoints from monitoring and alternate trial design were expressed.

Patient safety in pre-hospital emergency tracheal intubation: a comprehensive meta-analysis of the intubation success rates of EMS providers

Introduction

Pre-hospital airway management is a controversial subject, but there is general agreement that a small number of seriously ill or injured patients require urgent emergency tracheal intubation (ETI) and ventilation. Many European emergency medical services (EMS) systems provide physicians to care for these patients while other systems rely on paramedics (or, rarely, nurses). The ETI success rate is an important measure of provider and EMS system success and a marker of patient safety.

Methods

We conducted a systematic search of Medline and EMBASE to identify all of the published original English-language articles reporting pre-hospital ETI in adult patients. We selected all of the studies that reported ETI success rates and extracted information on the number of attempted and successful ETIs, type of provider, level of ETI training and the availability of drugs on scene. We calculated the overall success rate using meta-analysis and assessed the relationships between the ETI success rate and type of provider and between the ETI success rate and the types of drugs available on the scene.

Results

From 1,070 studies initially retrieved, we identified 58 original studies meeting the selection criteria. Sixty-four per cent of the non-physician-manned services and 54% of the physician-manned services reported ETI success rates but the success rate reporting was incomplete in three studies from non-physician-manned services. Median success rate was 0.905 (0.491, 1.000). In a weighted linear regression analysis, physicians as providers were significantly associated with increased success rates, 0.092 (P = 0.0345). In the non-physician group, the use of drug-assisted intubation significantly increased the success rates. All physicians had access to traditional rapid sequence induction (RSI) and, comparing these to non-physicians using muscle paralytics or a traditional RSI, there still was a significant difference in success rate in favour of physicians, 0.991 and 0.955, respectively (P = 0.047).

Conclusions

This comprehensive meta-analysis suggests that physicians have significantly fewer pre-hospital ETI failures overall than non-physicians. This finding, which remains true when the non-physicians administer muscle paralytics or RSI, raises significant patient safety issues. In the absence of pre-hospital physicians, conducting basic or advanced airway techniques other than ETI should be strongly considered.

Pre-hospital intubation factors and pneumonia in trauma patients

BACKGROUND

We reported similar rates of ventilator-associated pneumonia (VAP) previously in trauma patients intubated either in a pre-hospital (PH) venue or the emergency department. A subset of PH intubations with continuous quality assessment was re-examined to identify the intubation factors associated with VAP.

METHODS

The subgroup was derived from an existing data set of consecutive adult trauma patients intubated prior to Level I trauma center admission July 2007-July 2008. Intubation details recorded included bag-valve mask ventilation (BVM) and the presence of material in the airway. The diagnosis of VAP was made preferentially by quantitative bronchoalveolar lavage (BAL) cultures (≥ 10⁴ colony-forming units indicating infection). Baseline data, injury characteristics, and circumstances of intubation of patients with and without VAP were compared by univariable analysis.

RESULTS

Detailed data were available for 197 patients; 32 (16.2%) developed VAP, on average 6.0±0.7 days after admission. Baseline characteristics were similar in the groups, but diabetes mellitus was more common in the VAP group (4 [12.5%] vs. 5 [3.0%]; p=0.02). There was a higher rate of blunt injury in the VAP patients (28 [87.5%] vs. 106 [64.2%]; p=0.01) and higher injury severity scores (33.1±2.8 vs. 23.0±1.0; p=0.0002) and chest Abbreviated Injury Scores (2.6±0.3 vs. 1.5±0.1; p=0.002). Lower Glasgow Coma Scale scores (7.9±0.9 vs. 9.9±0.4; p=0.04) and greater use of BVM (18 [56.3%] vs. 56 [34.0%]; p=0.02) were observed in patients who developed VAP. Among aspirations, 10 (31.3%) of patients with emesis developed VAP compared with only 4 (12.5%) with blood in the airway (p=0.003).

CONCLUSION

Aspiration, along with depressed consciousness and greater injury severity, may predispose trauma patients to VAP. Prospective studies should focus on the quality and timing of aspiration relative to intubation to determine if novel interventions can prevent aspiration or decrease the risk of VAP after aspiration.

The need for standardized data reporting for prehospital airway management

Despite a widespread belief in the value of aggressive prehospital airway management, the therapeutic benefits of early tracheal intubation (TI) remain unclear. In fact, most attempts to elucidate the benefits of prehospital TI on outcome from traumatic brain injury and cardiopulmonary arrest have documented an increase in mortality associated with the procedure. While some degree of selection bias is likely present in these studies, the inherent adverse physiological effects of intubation and a high incidence of desaturation and subsequent hyperventilation may indicate a harmful effect of the procedure. This uncertainty regarding such a fundamental resuscitation procedure as TI underscores the need for standardized data reporting in prehospital airway management research. To this end, the Utstein prehospital airway conference proposed a set of variables that would move us in that direction. However, the present article by Lossius and colleagues documents how far we still have to travel before such standardization can be achieved. Only through these efforts can we elucidate the true benefits - or harm - of advanced airway management during critical resuscitation.

Revisiting the value of pre-hospital tracheal intubation: an all time systematic literature review extracting the Utstein airway core variables

Introduction

Although tracheal intubation (TI) in the pre-hospital setting is regularly carried out by emergency medical service (EMS) providers throughout the world, its value is widely debated. Heterogeneity in procedures, providers, patients, systems and stated outcomes, and inconsistency in data reporting make scientific reports difficult to interpret and compare, and the majority are of limited quality. To hunt down what is really known about the value of pre-hospital TI, we determined the rate of reported Utstein airway variables (28 core variables and 12 fixed-system variables) found in current scientific publications on pre-hospital TI.

Methods

We performed an all time systematic search according to the PRISMA guidelines of Medline and EMBASE to identify original research pertaining to pre-hospital TI in adult patients.

Results

From 1,076 identified records, 73 original papers were selected. Information was extracted according to an Utstein template for data reporting from in-the-field advanced airway management. Fifty-nine studies were from North American EMS systems. Of these, 46 (78%) described services in which non-physicians conducted TI. In 12 of the 13 non-North American EMS systems, physicians performed the pre-hospital TI. Overall, two were randomised controlled trials (RCTs), and 65 were observational studies. None of the studies presented the complete set of recommended Utstein airway variables. The median number of core variables reported was 10 (max 21, min 2, IQR 8-12), and the median number of fixed system variables was 5 (max 11, min 0, IQR 4-8). Among the most frequently reported variables were "patient category" and "service mission type", reported in 86% and 71% of the studies, respectively. Among the least-reported variables were "co-morbidity" and "type of available ventilator", both reported in 2% and 1% of the studies, respectively.

Conclusions

Core data required for proper interpretation of results were frequently not recorded and reported in studies investigating TI in adults. This makes it difficult to compare scientific reports, assess their validity, and extrapolate to other EMS systems. Pre-hospital TI is a complex intervention, and terminology and study design must be improved to substantiate future evidence based clinical practice.

Paramedic Rapid Sequence Intubation for Severe Traumatic Brain Injury: Perspectives from an Expert Panel

Although early intubation has become standard practice in the prehospital management of severe traumatic brain injury (TBI), many patients cannot be intubated without neuromuscular blockade. Several emergency medical services (EMS) systems have implemented paramedic rapid sequence intubation (RSI) protocols, with published reports documenting apparently conflicting outcomes effects. In response, the Brain Trauma Foundation assembled a panel of experts to interpret the existing literature regarding paramedic RSI for severe TBI and offer guidance for EMS systems considering adding this skill to the paramedic scope of practice. The interpretation of this panel can be summarized as follows: (1) the existing literature regarding paramedic RSI is inconclusive, and apparent differences in outcome can be explained by use of different methodologies and variability in comparison groups; (2) the use of Glasgow Coma Scale score alone to identify TBI patients requiring RSI is limited, with additional research needed to refine our screening criteria; (3) suboptimal RSI technique as well as subsequent hyperventilation may account for some of the mortality increase reported with the procedure; (4) initial and ongoing training as well as experience with RSI appear to affect performance; and (5) the success of a paramedic RSI program is dependent on particular EMS and trauma system characteristics.

Pre-hospital airway management: guidelines from a task force from the Scandinavian Society for Anaesthesiology and Intensive Care Medicine

This article is intended as a generic guide to evidence-based airway management for all categories of pre-hospital personnel. It is based on a review of relevant literature but the majority of the studies have not been performed under realistic, pre-hospital conditions and the recommendations are therefore based on a low level of evidence (D). The advice given depends on the qualifications of the personnel available in a given emergency medical service (EMS). Anaesthetic training and routine in anaesthesia and neuromuscular blockade is necessary for the use of most techniques in the treatment of patients with airway reflexes. For anaesthesiologists, the Task Force commissioned by the Scandinavian Society of Anaesthesia and Intensive Care Medicine recommends endotracheal intubation (ETI) following rapid sequence induction when securing the pre-hospital airway, although repeated unsuccessful intubation attempts should be avoided independent of formal qualifications. Other physicians, as well as paramedics and other EMS personnel, are recommended the lateral trauma recovery position as a basic intervention combined with assisted mask-ventilation in trauma patients. When performing advanced cardiopulmonary resuscitation, we recommend that non-anaesthesiologists primarily use a supraglottic airway device. A supraglottic device such as the laryngeal tube or the intubation laryngeal mask should also be available as a backup device for anaesthesiologists in failed ETI.

Early ventilation in traumatic brain injury

While airway and ventilatory compromise are significant concerns following traumatic brain injury (TBI), there is little data supporting an aggressive approach to airway management by prehospital personnel, and a growing number of reports suggesting an association between early intubation and increased mortality. Recent clinical and experimental data suggest that hyperventilation is an important contributor to these adverse outcomes in TBI patients. Various mechanisms appear to be responsible for the worsened outcomes, including hemodynamic, cerebrovascular, immunologic and cellular effects. Here, relevant experimental and clinical data regarding the impact of ventilation on TBI are reviewed. In addition, experimental data regarding potential mechanisms for the adverse effects of hyperventilation and hypocapnia on the injured brain are presented. Finally, the limited data regarding the impact of hypoventilation and hypercapnia on outcome from TBI are discussed.

Hyperventilation following aero-medical rapid sequence intubation may be a deliberate response to hypoxemia

BACKGROUND

Recent studies document a high incidence of hyperventilation by prehospital providers, with a potentially detrimental effect on outcome in traumatic brain injury (TBI).

PURPOSE

To document the incidence of hyperventilation by aero-medical providers and explore a possible relationship between hyperventilation episodes and desaturations or impending hypoxemia.

METHODS

This was a prospective, descriptive study using TBI patients undergoing prehospital RSI by aero-medical crews. Continuous data regarding end-tidal CO2 (EtCO2), ventilatory rate, and oxygen saturation (SpO2) were downloaded from hand-held oximeter-capnometer devices. Two investigators independently assessed oximetry/capnometry data to identify the following occurrences: desaturation during RSI (SpO2 < 90%), impending hypoxemia (SpO2 decrease by >or=3% to a value <95%) following intubation, loss of SpO2 signal, hyperventilation (EtCO2<30 mm Hg), and severe hyperventilation (EtCO2 < 25 mm Hg). Covariate analysis was used to explore the possible association between hyperventilation episodes and either desaturation, impending hypoxemia, or loss of SpO2 signal.

RESULTS

A total of 32 aero-medical patients were enrolled with a mean duration of ventilation monitoring of 14.8 min. The incidence of hyperventilation or severe hyperventilation was substantially lower than previously documented with ground paramedics. A total of 28 hyperventilation episodes were identified in 16 patients; 13 of these were associated with impending hypoxemia following intubation, five were associated with desaturation during RSI, and seven were associated with loss of SpO2 signal. The remaining three occurred immediately following intubation without desaturation during RSI. Desaturation was observed in 62% of patients; of note, desaturation was recorded on the quality improvement document in only 23% of these. Covariate analysis revealed an association between hyperventilation episodes and either desaturatios during RSI, impending hypoxemia following intubation, or loss of SpO2 signal.

CONCLUSIONS

The incidence of hyperventilation by aeromedical crews was lower than reported for ground paramedics and appears to occur in response to desaturation, impending hypoxemia, or loss of SpO2 signal.