Tracheomalacia after thyroidectomy for retrosternal goitres requiring sternotomy- a myth or reality?

INTRODUCTION

Tracheomalacia after thyroidectomy is not well understood. Reports on tracheomalacia are conflicting, with some suggesting a high rate and other large cohorts in which no tracheomalacia is reported. The aim of our study was to assess the incidence and factors associated with tracheomalacia after thyroidectomy in patients with retrosternal goitres requiring sternotomy at a high-volume tertiary care referral centre.

METHODS

A longitudinal cohort study was conducted from January 2011 to December 2019. All adult patients who underwent thyroidectomy with sternotomy were included. Tracheomalacia was considered when tracheal rings were soft compared with other parts (proximal or distal) of the trachea and required either tracheostomy or resection with anastomosis. The decision to perform a tracheostomy or to administer continuous or bilevel positive airway pressure postoperatively was made depending on the degree of tracheomalacia. Logistic regression analysis was used to assess factors associated with tracheomalacia.

RESULTS

We evaluated 40 patients who underwent thyroidectomy with sternotomy. The mean age of our cohort was 48.7 ± 11.3 years and the population was predominantly female (67.5%). One patient required tracheal resection with anastomosis, and two patients required tracheostomy. Multivariable logistic regression analysis did not reveal any patient- or thyroid-related factor significantly associated with the development of tracheomalacia in our cohort.

CONCLUSIONS

The incidence of tracheomalacia after thyroidectomy with sternotomy appears to be very low. However, the occurrence of tracheomalacia after thyroidectomy in cases of large goitre is possible and hence worrisome.

Combined use of a videolaryngoscope and a flexible bronchoscope for awake tracheal intubation when front-of-neck airway is not an option

We report a case of successful tracheal intubation with the combined use of a videolaryngoscope and flexible bronchoscope in a patient with difficult airway when both techniques had individually failed. A 35-year-old man presented with airway obstruction due to massive neck swelling causing hypoxia, stridor and respiratory distress. He had a history of oral cancer which had been resected with bilateral neck dissection and free flap reconstruction 2 months previously. Due to extensive anterior neck swelling, we judged that front-of-neck airway would not be a suitable approach. After unsuccessful attempts at awake tracheal intubation with videolaryngoscopy and flexible bronchoscopy separately, we combined both techniques with a successful outcome. By using a combined technique to address the specific problems presented by this case, a life-threatening emergency was resolved. This case highlights why it is useful for anaesthetists to be familiar with multiple techniques to awake tracheal intubation, both individually and in combination.

Risks to healthcare workers following tracheal intubation of patients with COVID-19: a prospective international multicentre cohort study

Healthcare workers involved in aerosol‐generating procedures, such as tracheal intubation, may be at elevated risk of acquiring COVID‐19. However, the magnitude of this risk is unknown. We conducted a prospective international multicentre cohort study recruiting healthcare workers participating in tracheal intubation of patients with suspected or confirmed COVID‐19. Information on tracheal intubation episodes, personal protective equipment use and subsequent provider health status was collected via self‐reporting. The primary endpoint was the incidence of laboratory‐confirmed COVID‐19 diagnosis or new symptoms requiring self‐isolation or hospitalisation after a tracheal intubation episode. Cox regression analysis examined associations between the primary endpoint and healthcare worker characteristics, procedure‐related factors and personal protective equipment use. Between 23 March and 2 June 2020, 1718 healthcare workers from 503 hospitals in 17 countries reported 5148 tracheal intubation episodes. The overall incidence of the primary endpoint was 10.7% over a median (IQR [range]) follow‐up of 32 (18–48 [0–116]) days. The cumulative incidence within 7, 14 and 21 days of the first tracheal intubation episode was 3.6%, 6.1% and 8.5%, respectively. The risk of the primary endpoint varied by country and was higher in women, but was not associated with other factors. Around 1 in 10 healthcare workers involved in tracheal intubation of patients with suspected or confirmed COVID‐19 subsequently reported a COVID‐19 outcome. This has human resource implications for institutional capacity to deliver essential healthcare services, and wider societal implications for COVID‐19 transmission.

Validation of acute physiologic and chronic health evaluation II scoring system software developed at The Aga Khan University, Pakistan

Objective:

To assess the predictive performance of Acute Physiologic and Chronic Health Evaluation II (APACHE II) software available on the hospital intranet and analyze interrater reliability of calculating the APACHE II score by the gold standard manual method or automatically using the software.

Materials and Methods:

An expert scorer not involved in the data collection had calculated APACHE II score of 213 patients admitted to surgical Intensive Care Unit using the gold standard manual method for a previous study performed in the department. The same data were entered into the computer software available on the hospital intranet (http://intranet/apacheii) to recalculate the APACHE II score automatically along with the predicted mortality. Receiver operating characteristic curve (ROC), Hosmer-Lemeshow goodness-of-fit statistical test and Pearson's correlation coefficient was computed.

Results:

The 213 patients had an average APACHE II score of 17.20 ± 8.24, the overall mortality rate was 32.8% and standardized mortality ratio was 1.00. The area under the ROC curve of 0.827 was significantly >0.5 (P < 0.01) and had confidence interval of 0.77-0.88. The goodness-of-fit test showed a good calibration (H = 5.46, P = 0.71). Interrater reliability using Pearson's product moment correlations demonstrated a strong positive relationship between the computer and the manual expert scorer (r = 0.98, P = 0.0005).

Conclusion:

APACHE II software available on the hospital's intranet has satisfactory calibration and discrimination and interrater reliability is good when compared with the gold standard manual method.

VLA-6 (CDw49f) is an important adhesion molecule in NK cell-mediated cytotoxicity following autologous or allogeneic bone marrow transplantation

Graft-vs.-leukemia (GVL) is postulated to be the principal mechanism responsible for continued remission after allogeneic bone marrow transplantation (BMT). The specific cytotoxic effectors mediating this effect are as yet undefined, but the major histocompatibility complex (MHC)-nonrestricted lysis of tumor cell lines by natural killer (NK) and lymphokine-activated killer (LAK) cells from recipients of allogeneic BMTs has been proposed as an in vitro correlate of GVL. In vitro culture or treatment in vivo with interleukin-2 (IL-2) is associated with enhanced NK cytotoxicity and lysis of NK-resistant targets (LAK cytotoxicity). NK, LAK, and cytotoxic T lymphocytes (CTL) have cytotoxic properties against autologous and allogeneic leukemic targets. These immune effector cells require receptor-ligand interaction for target recognition and adhesion via specific molecules such as integrins, a group of heterodimeric transmembrane glycoproteins. The integrins include the very late activation (VLA) subfamily, which all share the same beta 1 subunit but have distinct chains. VLA-6 (CDw49f) has been identified on NK cells and binds to laminin, a basement membrane protein found on malignant tumor cells but not normal cells. Monoclonal antibodies (mAbs) to laminin have been found to inhibit in vitro cytotoxicity of the tumor cell line K562, suggesting an important role for VLA-6 in this interaction. The specific aim of this study was to investigate the role of VLA-6 in the interactions of the tumor cell lines K562 and Daudi with peripheral blood lymphocytes (PBL) acting as effectors in cell-mediated cytotoxicity from normal volunteers, patients recovering from chemotherapy, and patients recovering from autologous or allogeneic BMT. In over 96% of assays, incubation of effector cells with anti-CDw49f mAbs led to detectable inhibition of NK and LAK cell-mediated cytotoxicity. More notably, the degree of anti-VLA6-induced suppression of LAK activity was significantly greater in the normal donors than in any of the patient groups, despite a significantly lower incidence of expression of VLA-6 on NK cells from controls than from patients. This implies a reduced role for this adhesion molecule in LAK activity following some form of in vivo stimulation. This hypothesis is supported by the observation that addition of exogenous IL-2 to the cultures ameliorated the effect of VLA-6 blockade, although the incidence and level of VLA-6 expression was unchanged by IL-2. In contrast, VLA-6 blocking led to a greater reduction in NK activity of BMT recipients than of normal donors, demonstrating that the VLA-6 adhesion pathway is important in this group of patients. These results indicate that the VLA-6-laminin interaction is important in normal NK-target interaction but may play a less significant role in the innate cytotoxic response post-BMT, perhaps reflecting subtle differences in the subsets of NK cells present in BMT recipients compared with normal donors.

Plasma soluble interleukin 2 receptor levels in patients with malignant lymphoma are correlated with disease activity but not cellular immunosuppression

Studies of peripheral blood lymphocytes (PBL) and plasma from patients with malignant lymphoma [Hodgkin's disease (HD) and non Hodgkin's lymphoma (NHL)] show that plasma soluble interleukin 2 receptor (sIL2R) levels are closely linked with disease status [normal volunteers (n = 15) 402 +/- 158 u/ml; patients with Hodgkin's disease in remission (n = 4) 525 +/- 195 u/ml or with active disease (n = 11) 3026 +/- 1602 u/ml (p < 0.001); patients with non Hodgkin's lymphoma in remission (n = 6) 462 +/- 202 u/ml, active disease (n = 15) 2713 +/- 1755 u/ml, (p < 0.001)] but no correlation between sIL2R and the inhibition of interleukin 2 (IL2) generated cytotoxicity for the cell line K562. In only 1 of 15 patient plasma samples studied was there a dose dependent inhibition of IL2 generated cell killing. In a further patient, IL2 generated K562 killing was inhibited at all doses (500-3000 brmp units/ml); treatment of this plasma with anti-Interleukin 4 (alpha IL4) had no effect on the potent inhibitory activity of the plasma. Plasma sIL2R levels were markedly elevated in patients receiving IL2 in vivo (pre treatment 520 +/- 170 IU/ml, during treatment 5578 +/- 2564 IU/ml, p = 0.05). The aetiology of immunosuppression in patients with lymphoma appears to be multi-factorial; although sIL2R correlates with disease activity it does not appear to directly mediate immunosuppression in most patients with malignant lymphoma.