Respiratory acidosis acute hypoventilation

Although the example of a foreign object lodged in the trachea is unusual, it is a useful illustration of the account which follows because the primary disorder starts suddenly, is maintained at a reasonably constant level and then may cease as suddenly as it started when the obstruction is removed. 

The rise in the alveolar PcOj results immediately in an equivalent rise in the arterial PCO2. As a result, the reaction 

To recapitulate briefly the basic defect is increased PCO2. For whatever reason, the subject cannot ventilate more and so cannot reduce the PCO2. Instead, the kidney adds bicarbonate to the blood as part of the physiological mechanism of minimizing changes in hydrogen ion concentration. The details of the renal mechanisms for this response are not fully understood but one contributing factor is that the raised PcOj in the renal tubular cells drives the reaction 

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In order to effectively treat respiratory acidosis, the causative process must be identified and treated. If a cause is identified, specific therapy should be started. This may include naloxone for opiate-induced hypoventilation or bronchodilator therapy for acute bronchospasm. Because respiratory acidosis represents ventilatory failure, an increase in... 

Respiratory acidosis may be acute or chronic. Acute conditions occur within minutes or htnirs. They are uncompensated. Renal compensation has no time to develop as the mechanisms which adjust bicarbonate reabsorption take 48-72 h to become fully effective. The primary problem in acute respiratory acidosis is alveohir hypoventilation. If airflow is completely or partially reduced, the PCO, in the bltHtd will rise immediately and the H ) will rise quickly (Fig. 2). A resulting low PO, and high PCO. causes coma. If this is not reliev ed rapidly, death results. 

This nomenclature is now applied to the sequence of events in hypoventilation. Within half an hour, the subject moves to a point which is described as acute or uncompensated respiratory acidosis . There is acidaemia. Over the course of the ensuing days, renal compensation occurs and the patient s blood is represented by a point which is described as compensated respiratory... 

Respiratory acidosis Hypoventilation of acute onset results in a change of blood biochemistry (along the normal, to a different) blood line, as shown by arrow. .. In the resultant uncompensated respiratory acidosis the alveolar PCO2 is... 

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