Oxygen, arterial blood gases and ventilation are unchanged during dialysis in patients receiving pressure support ventilation

Abstract

This study was undertaken to observe whether dialysis-induced alveolar hypoventilation and arterial hypoxaemia occur during bicarbonate haemodialysis in patients receiving partial mechanical support with pressure support ventilation. Nineteen patients admitted to the medical intensive care unit requiring mechanical ventilation and haemodialysis were enrolled. Arterial blood gas, white blood cell (WBC) count, minute ventilation, respiratory rate, breathing pattern and blood pressure were measured according to the following time schedule: pre-dialysis (time 0), and at 15, 30, 60, 120, 180, 240 min thereafter. Results showed that, with the use of cuprammonium dialyser, the WBC count dropped immediately and reached the nadir 15 min after haemodialysis. Thereafter, it recovered and overshot the pre-dialysis values until the end of dialysis. The bicarbonate dialysate indeed resulted in rapid and significant metabolic alkalosis. However, no decrease of PaO2 occurred throughout haemodialysis. The tidal volume, minute ventilation and breathing pattern remained stable during haemodialysis. We conclude that neither dialysis-induced alveolar hypoventilation nor arterial hypoxaemia developed during bicarbonate dialysis in patients mechanically ventilated with the pressure support ventilation.

Intradialytic Hypercapnic Respiratory Failure Managed by Noninvasive Assisted Ventilation

“…Normalization of uremic acidosis by high bicarbonate concentration dialysate is not usually associated with hypoxemia or significant increase in PCO 2 [7,8]. However, in patients on invasive mechanical ventilation, bicarbonate dialysis is associated with decreased respiratory drive, though without hypoventilation or hypoxemia [9,10]. Since our patient was managed by noninvasive ventilation, such a decrease in respiratory drive might have contributed to the exacerbation of hypercapnia.…”

“…Increased buffering results in increased production of CO 2 , but usually is not associated with significant hypercapnia or hypoxemia [7,8]. Bicarbonate dialysis has been associated with decreased respiratory drive in patients with respiratory failure on mechanical ventilation [9,10]. However, there are no data on the relation between bicarbonate dialysis and hypercapnia in nonmechanically ventilated hypercapnic hemodialysis (HD) patients.…”

Acute Effects of Intermittent Hemodialysis and Sustained Low-Efficiency Hemodialysis (SLED) on the Pulmonary Function of Patients under Mechanical Ventilation

“…To the best of our knowledge, there is no study about the effect of SLED on pulmonary function. Huang et al, [4] when studying 14 hemodynamically stable patients (most of whom presenting pulmonary congestion or pleural effusion in chest X-ray), did not find significant changes in PaO 2 , tidal volume, or respiratory rate after 240 minutes of IHD with cuprammonia rayon membrane. Nevertheless, they observed an improvement in auto PEEP, resistance of respiratory system, and dynamic compliance, and ascribed these findings to the achieved ultrafiltration (the patients lost 2.7 ± 1.4 Kg of body weight).…”

“…[2,3] However, the alterations induced by IHD on pulmonary function of mechanically ventilated patients have been described in few studies using cuprophane membrane. [4,5] Although less biocompatible than the synthetic membranes, the modified-cellulose membranes are more biocompatible than cuprophane and less expensive than the synthetic membranes. [6,7] In critically ill patients, IHD can induce hemodynamic instability and worsen systemic and pulmonary circulation mainly when its prescription is the same used for stable ESRD patients.…”

Numerical Study of Blood Partial Pressure of the Human Respiratory System

“…et al [3] developed a conceptual mathematical model of respiratory system. [4][5][6] The work related to the ear pressure, patients' reciving pressure, support ventilation, and arterial pressure fluctuations has already been discussed. Michiaki Yamakage et al [7,8] provided the idea of the modeling of human respiratory system and discussed to airways in body system .…”