Introduction
Patients with head and neck cancer (HNC) may undergo tracheostomy or laryngectomy either as part of their treatment or to bypass upper airway obstruction. Many of these patients have pre-existing respiratory co-morbidities. In a recent survey, 12 per cent of patients with HNC were reported to have chronic obstructive pulmonary disease (COPD) or asthma at diagnosis.Reference Landis, El-Hariry, van Herk-Sukel, van den Haak, Janssen-Heijnen and Penning-van Beest1
Pre-operatively, these patients were prescribed inhaled medications that become incompatible due to anatomical and functional changes following surgery. In particular, dry-powder inhaler (DPI), which is one of the most commonly used formulations, is rendered ineffective because patients can no longer generate sufficient inspiratory flow for optimal drug delivery.Reference Ari and Fink2 This high-risk population needs conversion to one of the three suitable formulations: nebuliser, soft-mist inhaler (SMI) or spacer-assisted pressurised metered-dose inhaler (pMDI). Otherwise, continuation of the DPI formulation is likely to result in suboptimal management of their respiratory co-morbidities and increased rate of respiratory complications, including hospital-acquired pneumonia and prolonged hospital stay.Reference van den Besselaar, Sewnaik, Hoesseini, Dorr, Baatenburg de Jong and Offerman3
Despite the clinical importance of inhaled medication delivery in this population, there is currently no clinical guidance to support appropriate formulation selection.4 In practice, formulation adjustments are implemented inconsistently and often depend on prescribers without specialised training in respiratory medicine or drug delivery systems. Moreover, the clinical impact of appropriate formulation selection on post-operative respiratory outcomes remains underexplored.
Objectives
To address this knowledge gap, we conducted the current study with the following aims:
• To evaluate the proportion of patients with respiratory co-morbidities undergoing tracheostomy or laryngectomy who were prescribed with appropriate inhaler formulation in existing practice
• To compare the incidence of post-operative respiratory complications between appropriately and inappropriately treated groups
• To assess the clinical impact of a newly implemented prescribing tool on prescribing patterns and incidence of post-operative respiratory complications
We hypothesise that appropriate inhaler formulation will be associated with a reduction in post-operative respiratory complications and that a structured prescribing tool will improve clinical decision-making and patient outcomes.
Methods
This cohort study adheres to Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidance on reporting and manuscript preparation. The study protocol was approved by the Clinical Audit Department of the local National Health Service (NHS) Trust. All participants gave written consent as part of their surgical consent form for their anonymised data to be used for research.
Study design and settings
The study was conducted in two cycles at a single tertiary otolaryngology centre. The first cycle was a retrospective cohort study examining existing prescribing practices. The second cycle was a prospective cohort study evaluating the effectiveness of the newly introduced prescribing tool in affecting prescribing practices and associated post-operative respiratory complications.
Data were extracted from electronic medical records, paper-based ward progress notes and medication administration records.
The prescribing tool used to guide formulation conversion was developed from a review of the licensed inhaled medications listed in the 2022 edition of the British National Formulary and the local hospital formulary.5 The prescribing tool presented a comprehensive list of commonly used DPIs, accompanied by their brand names, generic names and pictorial representations. These medications were matched with recommended alternatives in pMDI or SMI formulations to guide substitution. To ensure accuracy and clinical utility, feedback on the prescribing tool was sought from the hospital pharmacy team, and necessary revisions were made to finalise the prototype (Figure 1).
(A,B) Inhaler formulation conversions for patients undergoing tracheostomy or laryngectomy.
Participants
Patients were included if they underwent tracheostomy or laryngectomy and had a documented pre-existing respiratory co-morbidity requiring inhaled medications. The first cycle included patients from 1 October 2018 to 28 February 2022, and the second cycle included patients from 1 August 2023 to 31 July 2024. Each surgical intervention, even within the same patient, was analysed as a separate clinical encounter. For example, if the patient received both tracheostomy and laryngectomy during the same cycle, they were counted as 2 separate clinical encounters. Exclusion criteria included patients with incomplete records, those without a pre-existing respiratory co-morbidity and those not using inhaled medications prior to admission (Figure 2).
First and second cycles.
Main outcomes measures
The primary outcomes included: the percentage of clinical encounters where patients were prescribed inhalers in appropriate formulation and the incidence of post-operative respiratory complications.
An inhaler formulation was deemed appropriate if it was not a DPI and if it was either a SMI or spacer-assisted pMDI. Although nebulisers are considered appropriate, they were excluded from analysis as most patients received them only on a short-term basis post-operatively. Respiratory complications were defined as specific diagnoses (e.g., pneumonia, acute exacerbation of COPD) documented in ward progress notes, based on positive sputum culture, radiological evidence or clinical symptoms.
Patients were stratified by whether they received appropriate inhaler formulations. Post-operative respiratory outcomes were compared within each study cycle.
Results
Participant characteristics
A total of 20 clinical encounters involving 17 unique patients were included in the first cycle. A total of 20 clinical encounters involving 16 unique patients were included in the second cycle. Baseline characteristics — including average age, sex, diagnoses leading to tracheostomy or laryngectomy, pre-existing respiratory co-morbidities and types of operations — were comparable between the two cycles (Table 1).
Baseline characteristics
Prescribing practices
In the first cycle, patients received appropriate inhaler formulation in only 45 per cent (9/20) of clinical encounters following surgery. In the second cycle, this increased to 60 per cent (12/20) of clinical encounters, following implementation of the prescribing tool.
Respiratory complications
In both cycles, patients who received appropriate inhaler formulations experienced a lower incidence of post-operative respiratory complications (Table 2)
• In the first cycle, 22 per cent (2/9) of patients prescribed the appropriate formulation developed lower respiratory tract infections (LRTI), compared to 55 per cent (6/11) of those prescribed an inappropriate formulation;
• In the second cycle, 33 per cent (4/12) of patients prescribed the appropriate formulation developed LRTI, compared to 63 per cent (5/8) of those prescribed an inappropriate formulation.
Incidence of post-operative respiratory complications
Across both cycles, patients prescribed with appropriate inhaler formulations experienced fewer respiratory complications. However, the study lacked sufficient power to conduct formal statistical significance testing.
Discussion
This study highlights a significant gap in peri-operative management for patients with respiratory conditions undergoing tracheostomy or laryngectomy. Inhaled medications are frequently prescribed without adequate consideration of anatomical and functional airway changes. Consequently, drug delivery may be compromised, increasing the risk of post-operative complications. While Koroma et al. recently proposed a similar prescribing aid independently,Reference Koroma, Moors, Saiyed and Mehdi6 our study is the first to examine the impacts of a structured prescribing tool on real-world clinical practice and patient outcomes.
Clinical applicability and generalisability
This study is highly relevant to ENT practice, as many patients undergoing tracheostomy or laryngectomy for HNC also have respiratory co-morbidities. In this cohort, 26 per cent (20/77) in the first cycle and 41 per cent (20/49) of patients in the second cycle had pre-existing respiratory conditions. As smoking is a major risk factor for both COPD and HNC, clinicians will often need to prescribe inhaled medications as part of peri-operative management. It is vital to raise clinicians’ awareness of how these procedures affect drug delivery, as ensuring appropriate formulation selection can improve patient outcomes and expedite recovery.
The results indicated that the pMDI formulation continues to play an important clinical role in patients with respiratory co-morbidities undergoing tracheostomy or laryngectomy. Although the NHS has recently advocated for a switch toward DPI over pMDI formulation to reduce greenhouse gas emissions,7 spacer-assisted pMDI remains the preferred drug delivery system for this high-risk population.
Comparison to literature
Current literature provides no evidence supporting the successful use of DPI in patients with laryngectomy. For patients with tracheostomy, Meada et al. reported a case where a patient inhaled DPI orally while manually occluding her tracheostomy stoma.Reference Maeda, Yamaguchi, Nagase, Yasuno, Itagaki and Watanabe8 Her asthma symptoms appeared to be well-controlled, despite compromised inspiratory flow rate. Similarly, Johnson et al described the use of specially adapted interfaces to administer tiotropium and formoterol via the DPI devices Handihaler and Aeroliser, respectively.Reference Johnson9 However, the same study also noted that 17 per cent of patients could not fully empty the dry powder capsules independently, even with the use of these custom interfaces. Most DPIs lack custom-designed adapters to enable airtight seals with tracheostomy stomas. In contrast, pMDI formulation has long been adapted for use in patients with tracheostomy or laryngectomy. As early as the late 1990s, Nandapalan et al.Reference Nandapalan, Currey and Jones10 and Mirza et al.Reference Mirza, Hopkinson, Malik and Willatt11 demonstrated that pMDIs can be connected to stomas using small non-electrostatic spacers and facemasks.
Limitations
Limitations of the study include a small sample size and its single-centre setting. Additionally, the retrospective nature of the first cycle led to the exclusion of a substantial number of clinical encounters due to incomplete records. Furthermore, this study examined only post-operative prescribing practice. Optimising inhaler prescribing prior to elective procedures may further reduce the incidence of post-operative respiratory complications.
In the second cycle, the rate of appropriate prescribing remained suboptimal for this patient population. Several systemic factors likely contributed to this result, including frequent turnover of junior doctors who undertake most prescribing, occasional unavailability of specific drug formulations and lack of protocol dissemination to our intensive therapy unit (ITU) colleagues where some patients were transferred post-operatively. To enhance the rate of appropriate prescribing, we recommend embedding the prescribing tool in junior doctor inductions, incorporating the conversion step into part of the proforma clerking checklist, reviewing formulary recommendations for more reliably available formulations and extending dissemination to ITU.
A larger multi-centre study would strengthen generalisability. Further research is warranted to explore the development of formal guidelines for managing inhaled medications following tracheostomy and laryngectomy.
• Post-tracheostomy and post-laryngectomy airway changes can compromise inhaled medication delivery, thus exposing patients to suboptimal management of respiratory co-morbidities
• Dry-powder inhaler (DPI) should be converted to one of three formulations: nebuliser, soft-mist inhaler (SMI) or spacer-assisted pressurised metered-dose inhaler (pMDI)
• Our study demonstrated that, in a real-world clinical setting, a structured prescribing tool can facilitate appropriate formulation selection, improve clinical decision-making and reduce the risk of post-operative respiratory complications
• Refer to Figure 1 for the conversion chart developed and evaluated in this study
Conclusion
Patients undergoing tracheostomy or laryngectomy in an ENT setting often have pre-existing respiratory co-morbidities requiring inhalational treatment. However, anatomical and functional changes to the airway following these procedures can render many inhalational medications ineffective, if the formulation is not appropriately adapted. Current prescribing practices do not consistently modify the formulation to accommodate these changes, thus exposing these patients to higher risk of post-operative respiratory complications.
To address this issue, this study demonstrated that a simple prescribing tool to guide formulation conversion could improve the rate of appropriate prescribing and was associated with a reduction in post-operative respiratory complications.
Incorporating such a tool into routine clinical practice has the potential to optimise management of respiratory conditions in this high-risk population and improve post-operative outcomes. Due to this study’s small sample size and the single-centre design, further research is warranted to validate these findings and guide the development of formal prescribing guidelines.
