Management of haematoma after thyroid surgery: systematic review and multidisciplinary consensus guidelines from the Difficult Airway Society, the British Association of Endocrine and Thyroid Surgeons and the British Association of Otorhinolaryngology, Head and Neck Surgery

Haematoma after thyroid surgery can lead to airway obstruction and death. We therefore developed guidelines to improve the safety of peri-operative care of patients undergoing thyroid surgery. We conducted a systematic review to inform recommendations, with expert consensus used in the absence of high-quality evidence, and a Delphi study was used to ratify recommendations. We highlight the importance of multidisciplinary team management and make recommendations in key areas including: monitoring; recognition; post-thyroid surgery emergency box; management of suspected haematoma following thyroid surgery; cognitive aids; posthaematoma evacuation care; day-case thyroid surgery; training; consent and pre-operative communication; postoperative communication; and institutional policies. The guidelines support a multidisciplinary approach to the management of suspected haematoma following thyroid surgery through oxygenation and evaluation; haematoma evacuation; and tracheal intubation.
Keywords: airway; emergency; haematoma; haemorrhage; thyroid Twitters: @iliff_helen; @elboghdadly; @dr_imranahmad; @ShadKhanSurgeon; @grees34; @tarantatla2 Recommendations 1 All staff potentially interacting with patients undergoing thyroid surgery should be trained to recognise haematoma following thyroid surgery. This includes ward staff where patients are nursed and doctors of all grades and speciality.
2 Minimum monitoring includes wound inspection, early warning and pain scoring, as well as awareness for more subtle signs (agitation; anxiety; difficulty in breathing; discomfort). Why were these guidelines developed?
Postoperative haemorrhage is a well-recognised complication of thyroid surgery with an incidence between 0.45% and 4.2% [bib_ref] Postthyroidectomy hemorrhage: a national study of patients treated at the Danish departments..., Godballe [/bib_ref] [bib_ref] Post-thyroidectomy bleeding: analysis of risk factors from a national registry, Doran [/bib_ref]. Rapid haematoma formation, even with small volumes, can result in significant airway obstruction requiring emergency intervention. The unpredictability and potential risk of death due to haematoma following thyroid surgery supports the need for training that enables early recognition and management of the airway when haematoma is suspected [bib_ref] Patterns of post-thyroidectomy hemorrhage, Lee [/bib_ref]. Our aim was to produce recommendations that would improve patient safety by identifying key areas in clinical management, training and institutional preparedness.
These guidelines aim to support early recognition of haematoma following thyroid surgery and describe a systematic approach to airway management in patients who have had thyroid surgery, through individual and organisational preparedness. These guidelines are specific to thyroid surgery (lobectomy and total thyroidectomy), but the principles may apply to other forms of neck surgery.

## What guidelines currently exist?
There are several guidelines that describe the management of an anticipated difficult airway, and others describing the management of an unanticipated difficult airway [bib_ref] Difficult Airway Society guidelines for awake tracheal intubation (ATI) in adults, Ahmad [/bib_ref] [bib_ref] Difficult Airway Society 2015 guidelines for management of unanticipated difficult intubation in..., Frerk [/bib_ref] [bib_ref] Obstetric Anaesthetists' Association and Difficult Airway Society guidelines for the management of..., Mushambi [/bib_ref] [bib_ref] Recommendations for airway control and difficult airway management, Petrini [/bib_ref] [bib_ref] The difficult airway with recommendations for management -Part 1 -Intubation encountered in..., Law [/bib_ref] [bib_ref] Practice guidelines for management of the difficult airway: an updated report by..., Apfelbaum [/bib_ref] [bib_ref] All India difficult airway association 2016 guidelines for the management of unanticipated..., Myatra [/bib_ref] [bib_ref] All India difficult airway association 2016 guidelines for the management of unanticipated..., Ramkumar [/bib_ref] [bib_ref] Difficult intubation and extubation in adult anaesthesia, Langeron [/bib_ref] [bib_ref] Scandinavian SSAI clinical practice guideline on pre-hospital airway management, Rehn [/bib_ref] [bib_ref] Consensus guidelines for managing the airway in patients with COVID-19: Guidelines from..., Cook [/bib_ref].
These are usually in the setting of pre-operative or emergency airway management [bib_ref] Difficult airway management algorithms: a directed review, Edelman [/bib_ref]. However, the management of postoperative airway complications in the setting of head and neck surgery has not been previously published. Specifically, to our knowledge, there are no guidelines available supporting the multidisciplinary management of haematoma following thyroid surgery, either in the anaesthetic or in the surgical literature.
How do these guidelines differ from existing guidelines?
At the time of writing, there were no consensus recommendations, or nationally or internationally agreed guidelines on the management of suspected haematoma with or without airway compromise following thyroid surgery.

## Disclaimer
These guidelines are not intended to represent a minimum standard of practice, nor are they to be regarded as a substitute for good clinical judgement. They present key principles and suggested strategies for the management of

# Introduction
Patients requiring thyroid surgery are at risk of pre-, intraand postoperative airway compromise. The risk of preoperative and intra-operative airway obstruction can be mitigated with numerous strategies in surgical patients with predicted or unpredicted difficult airways [bib_ref] Difficult Airway Society guidelines for awake tracheal intubation (ATI) in adults, Ahmad [/bib_ref] [bib_ref] Difficult Airway Society 2015 guidelines for management of unanticipated difficult intubation in..., Frerk [/bib_ref]. In these settings, airway compromise usually occurs within controlled environments with immediate access to skilled staff to manage complications. However, airway obstruction following thyroid surgery may present once patients are in more remote areas, with higher patient to staff ratios, less frequent monitoring and lack of immediate access to appropriately skilled staff. This population is, therefore, potentially at greater risk of undetected or late-presenting airway compromise and subsequent mortality. Moreover, the nature of the anatomical structures in the neck places patients at risk of rapid clinical deterioration in the event of even a small haemorrhage, especially in the context of laryngeal oedema. Prompt assessment and management is required, occasionally necessitating bed-side haematoma evacuation with or without emergency tracheal intubation to avert significant morbidity and mortality.
There are more than 11,000 thyroid procedures performed annually in England alone and >150,000 in the USA; the scale of peri-operative adverse events in this cohort is substantial [bib_ref] Association of surgeon volume with outcomes and cost savings following thyroidectomy, Al-Qurayshi [/bib_ref]. Postoperative haemorrhage is a wellrecognised complication of thyroid surgery, with an incidence between 0.45% and 4.2%, which has not been reducing over time [bib_ref] Postthyroidectomy hemorrhage: a national study of patients treated at the Danish departments..., Godballe [/bib_ref] [bib_ref] Post-thyroidectomy bleeding: analysis of risk factors from a national registry, Doran [/bib_ref]. Evidence suggests that subsequent haematoma formation leads to acute airway compromise necessitating emergency bed-side intervention in up to a quarter of these patients [bib_ref] Patterns, timing and consequences of post-thyroidectomy haemorrhage, Farooq [/bib_ref] [bib_ref] Reoperation for bleeding after thyroid and parathyroid surgery: incidence, risk factors, prevention,..., Edafe [/bib_ref]. Although the incidence of mortality is poorly reported, death due to haematoma following thyroid surgery continues to occur. Some reported deaths have prompted institutional practice changes in the UK. While haemorrhage is the underlying mechanism, it is haematoma formation which usually requires immediate intervention due to risks of airway obstruction. For clarity, these guidelines specifically describe recognition and management of haematoma following thyroid surgery, and not haemorrhage.
Given the risk of death due to haematoma after thyroid surgery, there is a specific need to ensure safe perioperative care for this cohort of patients. To date, postoperative safety guidance has not been published, despite this being a period associated with high risk of morbidity and mortality [bib_ref] Risk factors for post-thyroidectomy haemorrhage: a meta-analysis, Liu [/bib_ref]. We therefore aimed to produce guidelines to support members of the multidisciplinary team in the management of postoperative haematoma following anterior cervical approach thyroidectomy by providing clear recommendations to enable organisational preparedness, early recognition and prompt clinical management. While the scope of these guidelines is specific, it is hoped that the principles presented may apply to other types of neck surgery, such as parathyroid, cervical spine or vascular surgery, and offer a basis to support future work in this area.

# Methods
These multidisciplinary consensus guidelines were Appendix S1. The results of the systematic review were then used to inform a Delphi study to formulate recommendations [bib_ref] Defining consensus: a systematic review recommends methodologic criteria for reporting of Delphi..., Diamond [/bib_ref] [bib_ref] Using and reporting the Delphi method for selecting healthcare quality indicators: a..., Boulkedid [/bib_ref]. An initial long list of 47 recommendations was recommendations. [bib_ref] Difficult Airway Society Guidelines for the management of tracheal extubation, Mitchell [/bib_ref] We also performed a survey to refine the recommended box contents. In the first round of the survey, an initial long list of 31 potential content items was presented to the Working Group and all members of the three represented Executive Committees (n = 31) to review and select essential items. An essential item was defined as "an item without which you could not perform the procedure." We prospectively determined to shortlist items of equipment receiving more than 20 votes. The items on this list were then ratified during a virtual round-table discussion by members of the Working Group.
The strength of recommendations was graded using a modified version of the system developed by the Centre for Evidence-based Medicine [bib_ref] The Difficult Airway Society "ADEPT" Guidance on selecting airway devices: the basis..., Pandit [/bib_ref] , as was used for previous airway guideline recommendations [bib_ref] Difficult Airway Society guidelines for awake tracheal intubation (ATI) in adults, Ahmad [/bib_ref]. Recommendations were graded A to D according to the strength of the available evidence [bib_ref] Difficult Airway Society guidelines for awake tracheal intubation (ATI) in adults, Ahmad [/bib_ref] [bib_ref] Summary of the British Thoracic Society guideline for diagnostic flexible bronchoscopy in..., Rand [/bib_ref] 

## Recognition
Early recognition of potential airway complications secondary to haematoma following thyroid surgery is critical. The acronym DESATS has been created to aid identification, which includes: difficulty swallowing/ discomfort; increase in early warning score (EWS) or There is no evidence to support the use of drains for prevention of haematoma in routine thyroid surgery [bib_ref] Risk factors for post-thyroidectomy haemorrhage: a meta-analysis, Liu [/bib_ref].
When used, it is important that staff are aware clot formation may prevent free drainage and provide false reassurance as haematoma can still form in the presence of drains.

## Post-thyroid surgery emergency box
The need for easy and rapid access to essential equipment in time-sensitive situations is well recognised in airway management. Tracheostomy guidelines promote bed-side availability of key emergency equipment [bib_ref] Multidisciplinary guidelines for the management of tracheostomy and laryngectomy airway emergencies, Mcgrath [/bib_ref] and others recommend dedicated sections for emergency front-ofneck airway equipment on difficult airway trolleys [bib_ref] Human factors and the 'next generation' airway trolley, Chrimes [/bib_ref]. This principle of immediate availability of essential equipment should be extended to patients following thyroid surgery.

## Management of suspected haematoma following thyroid surgery
In the event of a suspected haematoma following thyroid surgery, management should start with concurrent oxygenation and clinical evaluation progressing to haematoma evacuation and tracheal intubation when indicated .

## Oxygenate and evaluate
Concern about haemorrhage and or haematoma following thyroid surgery should prompt the immediate administration of supplemental oxygen (Grade D) and patients should be nursed in a head-up position before further assessment [bib_ref] Laryngeal exposure during laryngoscopy is better in the 25back-up position than in..., Lee [/bib_ref] (Grade C). The availability of portable lighting in ward settings may be advantageous (Grade D). [fig_ref] Figure 3: The Difficult Airway Society [/fig_ref]. The SCOOP approach was originally developed in response to a patient incident and has been adopted by several organisations since introduction [bib_ref] Reoperation for bleeding after thyroid and parathyroid surgery: incidence, risk factors, prevention,..., Edafe [/bib_ref]. Local anaesthetic infiltration is not required when opening the wound (Grade D).
Should haematoma evacuation fail to stabilise the patient, with no resolution of airway compromise and/or Local procedures may require this to be done separately to informing the anaesthetist.

## Intubate
In

## Cognitive aids
The use of cognitive aids can help when managing difficult clinical situations by outlining critical steps in the management process. They can improve communication by flattening hierarchies and structuring interactions [bib_ref] Cognitive aids: does patient safety depend on a manual?, Agarwala [/bib_ref].
During stressful critical incidents, they can reduce the cognitive load of the user and make it easier to take a structured approach [bib_ref] Cognitive aids: does patient safety depend on a manual?, Agarwala [/bib_ref] [bib_ref] The use of cognitive aids during emergencies in anesthesia: a review of..., Marshall [/bib_ref]. Therefore, cognitive aids should be available to support early recognition and management of haematoma following thyroid surgery [bib_ref] Cognitive aids: does patient safety depend on a manual?, Agarwala [/bib_ref] [bib_ref] The use of cognitive aids during emergencies in anesthesia: a review of..., Marshall [/bib_ref] (Grade D).
These guidelines include a number of cognitive aids [fig_ref] Figure 3: The Difficult Airway Society [/fig_ref]. They are related and designed to be used together. They cover key aspects of recognition and management relevant to the multidisciplinary team, rather than being directed at any single group of healthcare professionals. It is recognised that they will need to be used in tandem with other more specific guidelines, in particular for tracheal intubation and emergency front-of-neck airway [bib_ref] Difficult Airway Society guidelines for awake tracheal intubation (ATI) in adults, Ahmad [/bib_ref] [bib_ref] Difficult Airway Society 2015 guidelines for management of unanticipated difficult intubation in..., Frerk [/bib_ref] [bib_ref] Guidelines for the management of tracheal intubation in critically ill adults, Higgs [/bib_ref] , and have been designed to complement other training such as Advanced Life Support [bib_ref] ALERT course (Acute Life threatening Events-Recognition and Treatment), Villanueva [/bib_ref].

## Post-haematoma evacuation care

## Day-case thyroid surgery
Some units offer day-case thyroid surgery [bib_ref] Post-thyroidectomy bleeding: analysis of risk factors from a national registry, Doran [/bib_ref] [bib_ref] Day-case and shortstay surgery: the future for thyroidectomy?, Mirnezami [/bib_ref]. Discussion All organisations offering thyroid surgery should support members of the multidisciplinary team, including but not exclusive to anaesthetists, members of the arrest team, nursing staff and surgeons to attain and maintain competencies and skills required to manage acute complications specifically related to thyroid surgery [bib_ref] Major complications of airway management in the UK: results of the Fourth..., Cook [/bib_ref] [bib_ref] Major complications of airway management in the UK: results of the Fourth..., Cook [/bib_ref] (Grade C).

## Consent and pre-operative communication
There are several potential surgical complications highlighted to patients when acquiring informed consent for thyroidectomy. As a recognised complication of thyroid These guidelines were primarily produced to prioritise patient safety, by providing recommendations for members of the multidisciplinary team to manage patients with suspected haematoma following thyroid surgery. They aim to support current practice and complement staff training.
The supporting evidence available was limited despite postoperative haematoma being a well-recognised complication of thyroid surgery. The necessity of these guidelines is underscored by previous complications leading to patient deaths. Previously, the awareness of critical stages in recognition and management of haematoma following thyroid surgery may have been limited to those rotating through specialist teams. However, multidisciplinary management is necessary, which is highlighted by the diverse professional backgrounds of the Working Group. Institutional responsibility in identification and mitigation of risk requires organisations offering thyroid surgery to support the implementation of these recommendations in the interest of patient safety. The guidelines and recommendations provided are the first in this area and it is hoped they will support multidisciplinary team working, improving care and outcomes for patients having thyroid surgery.
[fig] 3: A post-thyroid surgery emergency box should be available at the bed-side of patients who have undergone thyroid surgery during the postoperative period, including during transfers. 4 Emergency front-of-neck airway equipment (scalpel; bougie; tracheal tube) must be readily available on wards caring for patients after thyroid surgery. 5 If concerned about potential haematoma following thyroid surgery, immediate senior surgical review (e.g. registrar or consultant) must be arranged. If senior surgical review is not immediately available, or if there are signs of airway compromise, a senior anaesthetist should be informed immediately. 6 If the patient shows signs of airway compromise due to haematoma, a systematic approach should be taken to open the wound at the bed-side. For this we recommend using the SCOOP approach (skin exposure; cut sutures; open skin; open muscles (superficial and deep layers); pack wound). [/fig]
[fig] 7: When emergency haematoma evacuation has taken place, it is important for the surgical team, usually the consultant, to communicate with the patient, including after discharge. This should include offering referral for clinical psychology support or similar. [/fig]
[fig] 8: All organisations offering thyroid surgery should support members of the multidisciplinary team, including but not exclusive to anaesthetists, nursing staff, members of the cardiac arrest team and surgeons, to attain and maintain competency and skills required to manage complications. [/fig]
[table] Table 1: Recommended contents of post-thyroid surgery emergency box. [/table]