Two cases of intraoperative herniation of the endotracheal tube cuff

Complications secondary to endotracheal intubation in dogs and cats – A questionnaire-based survey among veterinary anaesthesiologists

OBJECTIVE

To investigate anaesthesiologists' attitudes towards endotracheal intubation and the perceived incidence of complications secondary to endotracheal intubation in dogs and cats.

STUDY DESIGN

A cross-sectional online questionnaire-based study.

METHODS

Using an online questionnaire distributed via electronic mail, the perceived incidence of complications secondary to endotracheal intubation in dogs and cats was investigated. Attitudes towards endotracheal intubation, average caseload and percentage of animals intubated were examined. The study population consisted of Diplomates, Residents, and residency trained members of the American and European Colleges of Veterinary An(a)esthesia and Analgesia. Univariate descriptive statistics were calculated. For each complication, a mean incidence score (MIS) was calculated, ranging from 1 (never) to 5 (always). Additionally, a Wilcoxon signed-rank test and binary regression analyses were performed. A p value ≤ 0.05 was considered significant.

RESULTS

The overall response rate was 35.1%, with a completion rate of 26.6%. Most dogs and cats undergoing general anaesthesia were intubated. Endotracheal intubation was viewed as an integral part of modern anaesthesia. Significant differences were found in the incidence of 16 of the 24 examined complications between dogs and cats (p ≤ 0.001). The most frequently perceived complications were reported to be cuff leak (MIS 3.20) and coughing during intubation (MIS 3.10) in dogs, and coughing (MIS 3.01) and laryngeal spasm during intubation (MIS 2.91) in cats. Sociodemographic and practice-specific aspects did not appear to play a significant role in the reported incidence of complications.

CONCLUSIONS AND CLINICAL RELEVANCE

Endotracheal intubation was considered a state-of-the-art technique by the respondents. It was associated with a perceived low incidence of major complications and more frequent minor ones. Differences between dogs and cats need to be accounted for. Considering the retrospective and self-reporting nature of this survey, true incidences might differ.

Airway obstruction from tracheostomy balloon cuff herniation during oral cancer removal. Emergency successfully managed and lessons learnt from device malfunction

OBJECTIVE

Tracheostomy tube cuff balloon herniation is a rare event and can determine airway obstruction. Sometimes the obstruction is not very evident but, if it is not correctly solved, can determine a severe hypoxia with patient's death.

MATERIAL AND METHODS

We present a 49-year-old male patient, with cT4aN0M0 squamous cell carcinoma of the oral cavity, who was admitted to the hospital for definitive surgical resection. Due to mass an endo-oral intubation was not possible, so a surgical tracheotomy was performed. General anaesthesia was induced with Propofol (2 mg/kg) and Fentanil (1 mcg/kg) without gas. Surgery commenced via a trans-oral and trans-cervical approach, but it was halted after approximately 2 min as oximetry demonstrated a progressive fall from 98% to 78%. After confirmation of correct function of anaesthetic devices, the endotracheal cannula was tested; although surgeon deflated the tube cuff, repositioned the tube, and re-inflated the cuff, oxygen saturation did not change. So, the cannula was changed and patient's saturation increased up to normal value.

RESULTS

The balloon cuff of the cannula showed a herniation, responsible of insufficient ventilation.

CONCLUSIONS

Cuff herniation should be considered in case of unexpected airway obstruction, and a systematic, rapid approach to investigation and management should ensure timely identification and correction.

Modern Spirometry Supports Anesthetic Management in Small Animal Clinical Practice: A Case Series

Modern spirometry, like no other monitoring technique, allows insight into breath-to-breath respiratory mechanics. Spirometers continuously measure volume, airway pressure, and flow while calculating and continuously displaying respiratory system compliance and resistance in the form of loops. The aim of this case series is to show how observation of spirometric loops, similar to electrocardiogram or CO2 curve monitoring, can improve safety of anesthetic management in small animals. Spirometric monitoring cases described in this case series are based on use of the anaesthesia monitor Capnomac Ultima with a side stream spirometry sensor. The cases illustrate how recognition and understanding of spirometric loops allows for easy diagnosis of iatrogenic pneumothorax, incorrect ventilator settings, leaks in the system, kinked or partially obstructed endotracheal tube, and spontaneous breathing interfering with intermittent positive-pressure ventilation. The case series demonstrates the potential of spirometry to improve the quality and safety of anesthetic management, and, hence, its use can be recommended during intermittent positive-pressure ventilation and procedures in which interference with ventilation can be expected.

Breakage of two silicone endotracheal tubes during extubation

Silicone endotracheal tubes broke during tracheal extubation of two dogs after uneventful anaesthesia. The remaining pieces were removed via endoscopy, and both dogs recovered with no further problems. A third silicone endotracheal tube broke while checking for cracks prior to its use. Biofilm formation on the surface of the endotracheal tube is thought to be the main cause of the breakage. Destruction of the biofilm is difficult, therefore exhaustive cleaning with detergents followed by vigorous brushing is recommended to break the interaction between the silicone surface and the biofilm. It is suggested that careful attention is paid to how tubes are cleaned and dried (in a hanging position), and that they are checked carefully for cracks prior to each use.

Evaluation of the endotracheal tube cuff pressure resulting from four different methods of inflation in dogs

OBJECTIVE

To evaluate the endotracheal tube cuff pressure achieved by four different inflation methods.

STUDY DESIGN

Prospective clinical study.

ANIMALS

Eighty client owned dogs.

METHODS

After anaesthesia induction, endotracheal intubation was performed using plastic or silicone tubes. A clinician unaware of tube type inflated the cuff by simple digital palpation (method A), thereafter the cuff was deflated and inflated again by a second clinician who tried to reproduce a previously learned cuff pressure of between 19 and 24 mmHg (method B). During method C the cuff was inflated to the minimum occlusive volume at an airway pressure of 20 cm H(2) O, and in method D the cuff was incrementally deflated until an audible air leak could be heard from the oral cavity at an airway pressure of 25 cm H(2) O. For all the methods, an operator recorded the actual cuff pressure obtained using a manometer. Heart rate, respiratory rate and mean arterial pressure were monitored throughout the procedure.

RESULTS

The mean inflation pressure for plastic tubes was 56 ± 28 mmHg for method A, 20 ± 9 mmHg for method B, 35 ± 32 mmHg for method C and 46 ± 39 mmHg for method D. Pressures using silicone tubes were significantly higher than for plastic tubes, the mean registered pressures being 79 ± 39, 33 ± 16, 77 ± 50 and 92 ± 56 mmHg for methods A, B, C and D.

CONCLUSIONS AND CLINICAL RELEVANCE

None of the methods evaluated in this study can be considered effective for inflating the endotracheal tube cuff to within the optimal range when using silicone tubes. Direct measurement of the cuff pressure with a manometer is therefore recommended.