Impairment of chest wall mechanics and increased chest wall work of breathing cause postoperative respiratory failure in patients who have undergone radical esophagectomy

High Mechanical Power and Driving Pressures are Associated With Postoperative Respiratory Failure Independent From Patients' Respiratory System Mechanics

OBJECTIVES

High mechanical power and driving pressure (ΔP) have been associated with postoperative respiratory failure (PRF) and may be important parameters guiding mechanical ventilation. However, it remains unclear whether high mechanical power and ΔP merely reflect patients with poor respiratory system mechanics at risk of PRF. We investigated the effect of mechanical power and ΔP on PRF in cohorts after exact matching by patients' baseline respiratory system compliance.

DESIGN

Hospital registry study.

SETTING

Academic hospital in New England.

PATIENTS

Adult patients undergoing general anesthesia between 2008 and 2020.

INTERVENTION

None.

MEASUREMENTS AND MAIN RESULTS

The primary exposure was high (≥ 6.7 J/min, cohort median) versus low mechanical power and the key-secondary exposure was high (≥ 15.0 cm H 2 O) versus low ΔP. The primary endpoint was PRF (reintubation or unplanned noninvasive ventilation within seven days). Among 97,555 included patients, 4,030 (4.1%) developed PRF. In adjusted analyses, high intraoperative mechanical power and ΔP were associated with higher odds of PRF (adjusted odds ratio [aOR] 1.37 [95% CI, 1.25-1.50]; p < 0.001 and aOR 1.45 [95% CI, 1.31-1.60]; p < 0.001, respectively). There was large variability in applied ventilatory parameters, dependent on the anesthesia provider. This facilitated matching of 63,612 (mechanical power cohort) and 53,260 (ΔP cohort) patients, yielding identical baseline standardized respiratory system compliance (standardized difference [SDiff] = 0.00) with distinctly different mechanical power (9.4 [2.4] vs 4.9 [1.3] J/min; SDiff = -2.33) and ΔP (19.3 [4.1] vs 11.9 [2.1] cm H 2 O; SDiff = -2.27). After matching, high mechanical power and ΔP remained associated with higher risk of PRF (aOR 1.30 [95% CI, 1.17-1.45]; p < 0.001 and aOR 1.28 [95% CI, 1.12-1.46]; p < 0.001, respectively).

CONCLUSIONS

High mechanical power and ΔP are associated with PRF independent of patient's baseline respiratory system compliance. Our findings support utilization of these parameters for titrating mechanical ventilation in the operating room and ICU.

Assessment of chest wall movement following thoracotomy: a systematic review

Thoracotomy is a major cause of respiratory impairment, increasing the risk of postoperative pulmonary complications (PPC). Systems assessing ribcage kinematics may detect changes in chest expansion following thoracotomy and may thus aid in the development of patient-tailored chest physiotherapy. Hence, we aimed to identify studies assessing changes in chest wall movement following thoracotomy using objective measures. The Cochrane library, MEDLINE, EMBASE, Scopus and Web of Science databases were searched to find relevant articles providing an objective assessment of chest wall movement following thoracotomy. Methodological quality of included studies concerning chest wall movement following thoracotomy was assessed by use of QUADAS-2 tool. A total of 12 articles were included for the assessment of chest wall changes following thoracotomy using objective measures. Four studies measured changes in the cross-sectional area of the ribcage and abdomen using the respiratory inductive plethysmography (RIP), 1 study computed the chest wall compliance by monitoring the intra-pleural pressure, 3 studies measured changes in chest circumference with a simple tape measure and 4 articles performed a compartmental analysis of the chest wall volume by means of an optoelectronic plethysmography (OEP). There was no delay in the collection of data of the index test and reference standard, resulting in a low risk of bias for the flow and timing domain. Across all studies, participants underwent the same reference standard, resulting in a low risk of verification bias. Several objective measures were able to detect changes in chest wall displacement following thoracotomy and differed in the practical use and invasive nature. OEP allows a compartmental analysis of the chest wall volume. Hence, this system allows to assess chest wall movement changes following thoracotomy and the impact of different types of surgical approach. Furthermore, it could aid in the development of tailored physiotherapy.

Clinical review: liberation from mechanical ventilation

Mechanical ventilation is the defining event of intensive care unit (ICU) management. Although it is a life saving intervention in patients with acute respiratory failure and other disease entities, a major goal of critical care clinicians should be to liberate patients from mechanical ventilation as early as possible to avoid the multitude of complications and risks associated with prolonged unnecessary mechanical ventilation, including ventilator induced lung injury, ventilator associated pneumonia, increased length of ICU and hospital stay, and increased cost of care delivery. This review highlights the recent developments in assessing and testing for readiness of liberation from mechanical ventilation, the etiology of weaning failure, the value of weaning protocols, and a simple practical approach for liberation from mechanical ventilation.

Prone position to treat bronchopleural fistula in post-operative acute lung injury

OBJECTIVE

Prone position is used to treat patients with acute lung injury or acute respiratory distress syndrome because it improves gas exchange and respiratory mechanics. When broncho-pleural fistula occurring, the clinical impact of prone position is limited; however, its use could be tried when the fistula is small or other potential treatments are not possible.

METHODS

A 45-year-old man with oesophageal cancer submitted to a total oesophagectomy with intrathoracic transposition of the stomach developed post-operatively respiratory failure and pneumothorax, which were worsened by unilateral pleural rupture and severe subcutaneous emphysema produced after an attempt to introduce through anterior chest wall a second drainage tube.

RESULTS

Prone position associated with lung protective strategy was implemented during 16-18 h daily and after the change of position PaO2/FiO2 increased of 35% and PaCO2-PetCO2 decreased about 40%; at 4th day under treatment, the subcutaneous emphysema and pneumothorax could not be detected either clinically or radiologically. On the 6th day the lung lesion could not be observed under the CT-scan.

CONCLUSIONS

In a patient that underwent a major thoracic surgery the addition of prone positioning to protective lung ventilation rendered possible not only the healing of the acute lung injury, but also the quick repair of a lung rupture owing to a thoracic drainage attempt.