The use of the Hayek Oscillator during microlaryngeal surgery

Biphasic Cuirass Ventilation for Airway Surgeries: A Comprehensive Review

Airway surgeries pose great challenges for the anesthesiologists as the airway is shared by them and the surgeon. It is of paramount importance to have control of the airway during such surgeries. Many techniques have been employed to provide uninterrupted oxygenation to the patient with or without the presence of a definitive airway. Recently, biphasic cuirass ventilation (BCV) has been used effectively to provide tubeless airway management in patients undergoing airway surgeries. This article discusses the feasibility and viability of using BCV for various airway surgeries and also reviews the existing literature regarding its use in the perioperative period for such indications.

A Phase I trial of Non-invasive Ventilation and seizure prophylaxis with levetiracetam In Children with Cerebral Malaria Trial (NOVICE-M Trial)

Background

African children with cerebral malaria and seizures caused Plasmodium falciparum are at greater risk of poor outcomes including death and neurological sequelae. The agonal events are severe hypoventilation and respiratory arrest often triggered by seizures. We hypothesised that prophylactic anti-seizure medication (ASM) could avert 'spikes' of intracranial pressure during or following seizures and that adequate ventilation could be supported by biphasic Cuirass Ventilation (BCV) which requires no intubation.

Methods

A Phase I trial conducted in Kilifi, Kenya designed to provide data on safety, feasibility and preliminary data on seizure control using prophylactic ASM (levetiracetam) and BCV as non-invasive ventilatory support in children with cerebral malaria. Children aged 3 months to 12-years hospitalised with P falciparum malaria (positive rapid diagnostic test or a malaria slide), a Blantyre Coma Score ≤2 and a history of acute seizures in this illness are eligible for the trial. In a phased evaluation we will study i) BCV alone for respiratory support (n=10); ii) prophylactic LVT: 40mg/kg loading dose then 30mg/kg every 12 hours given via nasogastric tube for 72 hours (or until fully conscious) plus BCV support (n=10) and; iii) prophylactic LVT: 60mg/kg loading dose then 45mg/kg every 12 hours given via nasogastric tube for 72 hours (or until fully conscious) plus BCV support (n=10). Primary outcome measure: cumulative time with a clinically detected seizures or number of observed seizures over 36 hours. Secondary outcomes will be assessed by feasibility or ability to implement BCV, and recovery from coma within 36 hours. Safety endpoints include: aspiration during admission; death at 28 days and 180 days; and de-novo neurological impairments at 180 days.

Conclusions

This is a Phase I trial largely designed to test the feasibility, tolerability and safety of using non-invasive ventilatory support and LVT prophylaxis in cerebral malaria.

Registration

ISRCTN76942974 (5.02.2019); PACTR202112749708968 (20.12.2021).

Investigating the effect of materials and structures for negative pressure ventilators suitable for pandemic situation

The onset of the corona virus disease 2019 (COVID-19) pandemic caused shortages in mechanical ventilators (MVs) essential for the intensive care unit (ICU) in the hospitals. The increasing crisis prompted the investigation of ventilators which is low cost and offers lower health complications. Many researchers are revisiting the use of negative pressure ventilators (NPVs), due to the cost and complications of positive pressure ventilators (PPVs). This paper summarizes the evolution of the MVs, highlighting the limitations of popular positive and negative pressure ventilators and how NPV can be a cost-effective and lower health complication solution. This paper also provides a detailed investigation of the structure and material for the patient enclosure that can be used for a cost-effective NPV system using ANSYS simulations. The simulation results can confirm the selection and also help in developing a low cost while based on readily available materials. This can help the manufacturer to develop low-cost NPV and reduce the pressure on the healthcare system for any pandemic situation similar to COVID-19.

Novel Use of Biphasic Cuirass Ventilation During Definitive Radiation Therapy: A Technical Report

The use of biphasic cuirass ventilator supported radiation therapy has never been documented. We present the first technical report here. A 57-year-old man with obstructive sleep apnea presented with a T0N1M0 right sided, human papillomavirus related head and neck cancer diagnosed on excisional lymph node biopsy. On further workup, the cancer was found to have originated in the right tonsil and was staged as T1N1. The patient started definitive treatment with concurrent chemo-radiation therapy, but after 5 treatments was no longer able to lay in a supine position for treatment. Diagnostic imaging workup eventually revealed an idiopathic right sided hemi-diaphragm eventration. After consultation with cardiology, pulmonology, and head and neck surgery, recommendation was made for tracheostomy to tolerate supine radiotherapy position, but the patient refused. Instead, computed tomography simulation for radiotherapy replanning was performed using a combination of biphasic cuirass ventilation, home continuous positive airway pressure and oxygen. The patient then tolerated definitive treatment to a dose of 69.96 Gray in 33 fractions with concurrent chemotherapy and experienced no unexpected side effects. Although complex, daily treatment setup was consistent. Daily onboard imaging was precise and accurate. The patient continues to follow up with radiation oncology, medical oncology, and pulmonology. This is the first use of biphasic cuirass ventilator supported radiotherapy reported in the scientific literature. Although daily treatment setup is complex, its use could be considered in patients unable to tolerate radiation therapy treatment positioning as an alternative to tracheostomy.

Comparison of active cycle of breathing and high-frequency oscillation jacket in children with cystic fibrosis

High-frequency chest compressions (HFCC) have been suggested as an alternative to conventional chest physiotherapy to aid sputum clearance in patients with cystic fibrosis (CF). We aimed to compare the active cycle of breathing techniques (ACBT) with the Hayek Oscillator Cuirass, performing HFCC on secretion clearance in children with CF during an exacerbation. Ten children (7 males; median age, 14 years; range, 9-16) received either two supervised sessions using HFCC or two self-treatment ACBT sessions in random order on successive days. Baseline pulmonary function was similar prior to treatments. Sputum weight increased significantly with ACBT compared with HFCC during treatment (5.2 g vs. 1.1 g, P < 0.005, morning; 4.1 g vs. 0.7 g, P < 0.01, afternoon). Pulmonary function improved significantly after morning ACBT (forced vital capacity (FVC): 2.67 l to 2.76 l, P < 0.03; forced expiratory volume in 1 sec (FEV1): 1.59 l to 1.62 l, P < 0.03). Following afternoon ACBT, there was a significant increase in FVC (2.64 to 2.79, P < 0.02), but no significant change in FEV1. Pulmonary function did not change at any time following HFCC. Compared with ACBT, HFCC by Hayek Cuirass is not an effective airway clearance treatment modality for children with CF during an infective exacerbation.

Non-conventional respiratory support modalities applicable in the older child. High frequency ventilation and liquid ventilation

HFV, LV, and several other novel therapies offer promise to adults and children that the mortality associated with respiratory failure may be affected. Although there are several forms of HFV, HFOV is presently gaining favor in the treatment of severe respiratory failure and has generally supplanted HFJV in pediatric critical care. HFOV has the advantage of having an active expiratory phase, which helps to minimize air trapping and better modulate mean lung volume. Ventilators with sufficient power to perform HFOV in adults are currently under investigation, although there is a growing experience in using current ventilators in larger patients. To date, however, demonstration of lowered mortality with HFOV is lacking although intermediate outcome indicators are improved. PLV also offers promise in the treatment of ARF through its drastic ability to improve oxygenation, ventilation, and compliance in many lung injury models. Human trials are presently underway, but the optimal delivery of this novel therapy still necessitates extensive investigation. TLV is likely even more removed from general clinical application given the necessity of developing a new generation of ventilators for the delivery of liquid tidal volumes. How these and other modalities may piece together to improve the condition of our patients who have respiratory failure remains to be seen, but certainly, present and future investigation will be intriguing for years to come.

Transesophageal echocardiographic evaluation during negative-pressure ventilation using the Hayek oscillator

OBJECTIVES

To evaluate the effects of negative-pressure ventilation (NPV) on hemodynamics using the Hayek oscillator (Breasy Medical Equipment, London, UK) and to determine whether the oscillation frequency can modify the hemodynamics, assessed by transesophageal echocardiography (TEE).

DESIGN

A prospective study.

SETTING

A university hospital.

PARTICIPANTS

Eleven American Society of Anesthesiologists class I patients undergoing orolaryngeal surgery.

INTERVENTIONS

The ultrasound probe was inserted under general anesthesia. After baseline measurements were determined during spontaneous breathing, the frequency was changed from 30 to 60 to 120 cycles/min, consecutively. The left ventricular end-diastolic area (LVEDA), end-systolic area (LVESA), fractional area change (LVFAC), and end-systolic wall stress (ESWS) were determined. The velocities of the pulmonary artery (PA) flow, pulmonary venous (PV) flow, and transmitral flow were measured by pulsed Doppler techniques.

MEASUREMENTS AND MAIN RESULTS

PaO2 increased and PaCO2 decreased significantly. NPV caused a significant increase in the LVEDA, whereas it did not significantly change the PA velocity. ESWS, an index of afterload, remained unchanged.

CONCLUSION

The authors conclude that NPV using the Hayek oscillator induces an increase in the LVEDA without any changes in PA velocity, suggesting increased transmural pressure rather than increased preload, and that the three different frequencies do not modify the effects on the hemodynamics.