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# Management of anaesthetic emergencies and complications outside the operative room

Marc Garnier, Francis Bonnet

► To cite this version:

Marc Garnier, Francis Bonnet. Management of anaesthetic emergencies and complications outside the operative room. Current Opinion in Anaesthesiology, 2014, 27 (4), pp.437 - 441. 10.1097/aco.000000000000088. hal-04414385

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# Management of anaesthetic emergencies and complications outside the operative room.

Marc Garnier, MD, MSc¹,²; Francis Bonnet, MD, FRCA¹,²

¹ Anaesthesiology and Intensive Care Department, Hôpital Tenon, APHP, Paris, France.

² Pierre & Marie Curie School of Medicine – Pierre & Marie Curie University (Paris VI), France.

**Corresponding author:**

Dr Marc Garnier

Département d'Anesthésie et Réanimation – Pôle TVAR

Hôpital TENON

4 rue de la Chine

75020 Paris

France

Tel: 33 1 56 01 51 53 ; Fax: 33 1 56 01 60 97

E-mail: marcgarnier@gmail.com

**Word count:** 2180 words; **Abstract:** 200 words
**Abstract** (200 words)

**Purpose of review:** Anaesthesia outside the operating room is commonly uncomfortable and risky. In this setting, anaesthetic emergencies or complications may occur. This review aims to report the most recent updates regarding management of prehospital anaesthesia, anaesthesia in the trauma and emergency rooms, and anaesthesia for endoscopy and interventional radiology.

**Recent findings:** After tracheal intubation failure, airway control of outpatients could be achieved by pharmacologically-assisted laryngeal mask insertion. Management of traumatic injured patients is best guided in the frame of checklists. Monitoring sedation in this setting is challenging notably due to the threat of haemodynamic instability. Unfortunately, BIS monitoring cannot be recommended to guide sedation in this setting. Ketamine can be used to prevent hypotension during prehospital anaesthesia or procedural sedation; especially since its neuroprotective effects have been recently best understood.

TCI propofol administration with small concentration increments is adapted to prevent hypotension and hypoxaemia during sedation for gastrointestinal endoscopy and interventional radiology. TCI remifentanil administration is also adapted to many procedures.

**Summary:** Anaesthesia outside the operating room requests careful monitoring to avoid side effects and education of non-anaesthetists when they are involved. A useful tool is to continuously improve protocols and checklists to make anaesthesia in this setting safer.

**Key words:** anaesthesia outside the operating room, prehospital anaesthesia, emergency anaesthesia, procedural sedation, non-anaesthesiologist-provided sedation.
**Introduction**

Anaesthesia outside the operating room (OR) is a miscellaneous but frequently risky situation, potentially leading to an over-risk of complications (1). Delocalization of the technical platform, absence of anaesthetic colleagues in the neighbourhood, reduced access to material, drugs or help, and sometimes, emergency context, make anaesthesia in this setting, a balancing exercise in a single-engine plane whereas planned anaesthesia appears like a calm long haul flight. Several different situations may be encountered such as prehospital anaesthesia; anaesthesia in the emergency room; anaesthesia in technical platforms for bronchoscopy, digestive endoscopies, or interventional radiology. The aim of this review is to focus on the most recent data available regarding the management of anaesthetic emergencies and complications outside the operating room.

**Prehospital anaesthesia**

Prehospital management of medical emergencies and trauma patients is differently organized in western countries. However, facing to an increasing number of calls, a common challenge is maintaining the capacity to provide adequate critical care to the minority of severely ill or injured patients for whom it is requested. The department of emergency care in Bristol has listed the competencies of their three kinds of prehospital care providers: the paramedics, the critical care paramedics and the prehospital critical care physicians (2). One of the main additional competencies of critical care providers, compared with paramedics, is the ability to induce and maintain anaesthesia, and to perform procedural sedation.

The prehospital critical care providers have to be perfectly trained to rapid sequence anaesthetic induction (RSI) and tracheal intubation, which are the gold standard for patients requiring urgent controlled ventilation. In intubated patients, a particular attention should be given on tracheal tube cuff pressure because overinflation of the cuff is common in these circumstances. Indeed, in a prospective study performed in Switzerland, the median cuff pressure after intubation and emergency transfer was 58 cmH₂O, high above recommended values (3). A manometric control was used in only 2 cases of the 59 emergency transfers, leading to reduce median cuff pressure to less than 30 cmH₂O. No significant difference in cuff pressures was documented when patients were managed by anaesthetists or non-anaesthetists.

In case of failure to perform successful tracheal intubation, pharmacologically-assisted laryngeal mask (PALM) insertion could be used as an alternative. PALM procedure with a
second-generation airway device, is a rescue technique that takes place before surgical access to the airway in difficult intubation algorithms. A consensus statement (4) regarding PALM, has recently recommended that the PALM procedure could be considered in a patient with a severely compromised airway, when all routine measures have failed, and that the procedure could be located on the airway management ladder in a similar position to a surgical airway access although it was also reported that surgical airway access was a rescue technique in case of PALM failure. No preference was expressed for any anaesthetic agent but midazolam and ketamine, two drugs commonly used by emergency care physicians, were found appropriate for PALM insertion.

The level of sedation is actually quite difficult to assess in the setting of emergency medicine. Low levels of sedation, leading to awareness and implicit memory, are common because haemodynamic instability is considered as a threat restraining anaesthetic drugs administration. Assessment of sedation is mainly based on clinical scores. A recent BIS monitoring evaluation in prehospital patients has documented moderate agreement with Ramsay score, and poor correlation coefficient for repeated measures (5). Thus, BIS monitoring cannot be recommended to guide sedation or anaesthesia in prehospital patients.

## Anaesthesia in the emergency and trauma rooms

Time is determinant in the management of trauma injuries. An American staff has recently reported its good experience in the use of the intensive care unit (ICU) as an operative location for critically injured patients (6). We believe that this solution could be encouraged in particular settings, for example if an emergency operating room is not immediately available, provided a multidisciplinary written protocol have been beforehand drafted and implemented, and the surgical and anaesthetic teams trained.

However, regardless to surgery location, there is a need for making rapidly the good diagnosis and simultaneously to initiate a treatment to improve patient’ condition. Due to these constraints, management of traumatic injured patients is best guided in the frame of checklists. A guideline has been recently published in *Anesthesia-Analgesia* (7**). The checklist introduced by the Society of Critical Care Anaesthesiologists deals with measures required before and on patient hospital arrival; recommendations for induction and per-operative resuscitation; and few advices for postoperative management. A special attention should be paid to the prevention of hypothermia including the increase of the operating room temperature before patient’ arrival; to the implication of an anaesthetist from the beginning of
the supportive care administration; to the concept of hypotensive resuscitation; and to the
pharmacological aspects of the rapid sequence induction. The threshold values of systolic and
mean arterial blood pressures to be maintained, are still a matter of controversy although a
systolic arterial pressure above 100 mmHg (especially in head trauma patients) and a mean
arterial pressure above 60 mmHg appear reasonable values until definitive control of bleeding
is achieved

Etomidate remains the most frequently used anaesthetic agent in the haemodynamically
unstable patient, outside the operating room. However, even a single dose of etomidate may
impair the hypothalamic-pituitary-adrenal axis. Clinical consequences on outcomes are
unclear. An increase in morbidity has been reported, but in contrast Etomidate is less likely to
cause hypotension during haemorrhagic shock, which is major factor of poor prognosis.
Ketamine could be used as an alternative because recent updates confirms that ketamine
preserve cardiovascular stability via a sympathomimetic effect balancing its negative
inotropic effect (8,9). Moreover, recent data have challenged old case-control studies,
documenting that in mechanically ventilated patients, ketamine alone or in combination with
others anaesthetic agents, can be safely used in patients with elevated intracranial pressure.
Additional neuroprotective effects (in particular prevention of neuronal apoptosis) has also
been suggested (10*).

Ketamine is also available for procedural sedation in the emergency department making physicians comfortable because it preserves spontaneous breathing and airway reflexes, and maintains cardiovascular stability. A randomized study conducted in fractured patients supports its use in this context (11). The association of ketamine with low dose midazolam provided less hypoxia and lower pain scores during fracture reduction than midazolam-fentanyl. A 1.0 mg/kg intravenous loading-dose of ketamine in adults, possibly followed by incremental doses, could be recommended for procedural sedation in emergency patients (8). Nevertheless, Ketamine induces agitation, confusion and hallucinations in 10 to 20% of the patients. "Ketofol", a 50/50 mixture of ketamine and propofol in the same syringe, has been documented to provide better sedation consistency than propofol alone, without any increase in respiratory side effects (12, 13). However, the risk of agitation on awakening persists. Consequently, others have advocated to use the combination of the two drugs maintaining independent dosing (14).

The need for procedural sedation outside the operating room has increased in pediatric
patients, due to an increased demand of invasive diagnostic and therapeutic procedures. In
this context, anaesthetists cannot perform all procedural sedation and paediatricians are
increasingly involved to provide anaesthesia outside the operating room. A report of more
than 12.000 sedations performed by paediatricians in the USA, showed that several
complications were more frequent compared to procedures supervised by an anaesthetists, in
particular for inadequate sedation (2.2% vs 0.9% - P<0.001) (15). However, the definition of
"adequate" or "inadequate sedation" is very subjective. To comply the recommendations of
the American Society of Anesthesiologists and the American Academy of Pediatrics to
monitor the level of consciousness during such procedures, the great majority of physicians
use sedation scales, like the "University of Michigan Sedation Scale" and the "Observer's
Assessment of Alertness/Sedation", both validated in children. A recent prospective blinded
study conducted in a paediatric emergency department has reported a poor correlation
between BIS values and the physicians' clinical perception (16). In this study, physicians
underestimated the maximum level of sedation in about 90% of the cases, with nearly 80% of
patients having BIS values less than 60 (defining profound sedation or anaesthesia). The
development of simple protocols for sedation outside the operating room may be useful.
Ketamine can be used safely in this purpose, as it is for adult procedures. A prospective
randomized study supports this thought showing that ketamine allowed faster sedation and
recovery than midazolam, with an adapted level of sedation, during performance of a
paediatric urodynamic procedure (17). Another randomized double-blinded study performed
during laceration repair in the pediatric emergency department, has confirmed that oral
ketamine in association with midazolam procures a deeper sedation than oral midazolam
alone, with less intravenous drug recourse (18).

Anaesthesia for endoscopies and interventional radiology

Complications of anaesthesia for endoscopy are rare but remain a matter of concern as the
procedures they supply are not especially risky. In a recent prospective multicenter survey of
191.142 patients, propofol sedation-related complications occurred in only 82 procedures, and
deaths in 6 patients (3.10⁻⁵) (19). Most of the lethal complications occurred during emergency
endoscopies, and all occurred in ASA 3 patients. Another prospective study conducted during
colonoscopies under propofol sedation reported a higher incidence of complications of about
6% (20). If the experience of the endoscopist impacted the incidence of overall complications,
it was not the same for the anaesthesia team. This result could be, at least partially, explained
by the fact that applying and monitoring adapted anaesthetic protocols is more important than
the operating physician himself. This is even more important for non-anaesthesiologist-provided procedural sedation (NAPPS).

Propofol target-controlled infusion (TCI) is now the reference for a series of diagnostic and therapeutic digestive endoscopic procedures. However, side effects such as hypotension and arterial oxygen desaturation may occur. A reasonable effect-site target concentration (Ce) may prevent this risk. A recent report suggested that a propofol target concentration of 1.5 to 2.5 µg/mL, following a small bolus of midazolam/fentanyl, maintain a favorable balance between efficiency and tolerance (21). Titration of the target concentration is also important for tolerance. A prospective randomized study investigating 3 titration regimens (by 0.1, 0.2 and 0.5 µg/mL) has been closed before ending due to safety concerns (22). Increasing Ce by 0.5 µg/mL was significantly associated with more hypoxaemia. On the contrary, there was a trend for more frequent adjustments for 0.1 µg/ml increments, suggesting that 0.2 µg/mL was the best choice.

Using balanced sedation may reduce propofol total dose and related complications. This modality has been particularly developed in response to non-anaesthesiologist-provided procedural sedation. However, no difference in the efficiency, safety, procedure outcomes and complications has been documented, comparing propofol alone or combined with midazolam and fentanyl when sedation was performed by a well trained sedation team including two sedation nurses and a recovery room nurse (23). A meta-analysis of 22 RCTs concerning sedation for gastrointestinal endoscopy supports these results. Despite a significant reduction in the propofol total dose no effect on the incidence of hypoxaemia, hypotension, arrhythmias nor memorization was noted when propofol was combined with other traditional sedative agents (24*).

Eventually, the use of remifentanil TCI for sedation during flexible fiberoptic bronchoscopy was recently reported in ICU patients in a small single center study (25). Remifentanil guarantees rapid onset and short duration of action, and no tissue accumulation. With a maximum target concentration of 2.5 ng/mL in mean, low levels of pain and good patient satisfaction were achieved during the procedure. This proof of concept is based only on a few patients, but we believe that this sedative regimen is very interesting. In fact, our team used remifentanil TCI in this indication since 8 years with very good results.

In a large series of patients scheduled for interventional radiology serious complications occurred in less than 1% of the procedures (26). In this retrospective study including about 39.000 procedures, 12 cases of cardiopulmonary arrests were noted. This represents a low
incidence, but the 1-year mortality rate was high. Placement of intravenous devices for haemodialysis was a strong risk factor of complications (RR 5,2), involving a careful management of its sedation, in particular in the NAPPS era. To this end, review articles are published to educate radiologists to the practice of sedation (27*). On the other hand, anaesthetists need to be informed of the radiologic proceedings. An extended review of anaesthesia for embolization of cerebral aneurysms is available in this issue. The technical aspects and anaesthetic implications of other procedures are available in a very exhaustive and up-to-date review (28**).

## Conclusions

Anaesthesia and sedation outside the operating room remains a challenge for anaesthetists who must guarantee the safety and comfort of patients sometimes in difficult conditions. Checklists and algorithms have been developed and recently updated to improve critically injured and trauma patients' care. In this setting, ketamine returns on the centre stage due to its interesting properties. During anaesthetic and sedative procedures, monitoring appears as a cornerstone. Multiple demands for sedation in patients scheduled for invasive new procedures including interventional radiology require adaptation to the goal and the constraints of each procedure. In some places anaesthetists' shortage implies that non-anaesthetists need to be educated on the management of simple sedative procedures within a predetermined frame to avoid an increase in the incidence of complications.
**Key points**

* Pharmacologically-assisted laryngeal mask insertion of a second-generation device could be considered in outpatients with severely compromised airways.

* Management of traumatic injured patients is best guided in the frame of checklists, like that recently proposed by the Society of Critical Care Anaesthesiologists.

* Ketamine returns on the centre stage for prehospital and outside the operating room sedations, due to its interesting properties notably regarding its capacities to preserve haemodynamic stability and its neuroprotective effects.

* TCI propofol administration with small concentration increments is adapted to prevent hypotension and hypoxaemia during sedation for gastrointestinal endoscopy and interventional radiology.

* TCI remifentanil is also adapted for many endoscopic or interventional procedures, notably in intensive care patients.

**Acknowledgements and funding**

This work has not been funded by any external source.

**Disclosure**

The authors have no conflict of interest for the topic of this article.
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