Ulrica Lennborn: Intoxications, Drugs and Blood concentrations in the Intensive care unit: Before and after death

Abstract

Most patients admitted to the intensive care unit (ICU) require analgesic or sedative drugs to be able to undergo the medical treatment given. These drugs are given according to standard dosages. Achieved blood concentrations of these drugs and how they correlate to pain and sedation levels are not fully known in critically ill patients.

Intoxicated patients are common in intensive care. Drug concentration findings in blood among self-poisoned individuals need further investigation. Also, blood concentration changes of analgesic and sedative drugs after death in intensive care patients have not been previously described.

The objective of Study I was to develop and validate a technical analyses method to be able to analyze the analgesic and sedative drugs investigated. The method was validated and used to analyze all blood samples in the following studies in an efficient and correct way. 

In Study II a population of living patients in a general ICU was described regarding given dosages, clinical responses and measured blood concentrations. Recommended dosage intervals were followed and only 3 % of concentrations were above the therapeutic interval. There was no correlation between measured concentrations and perceived pain or sedation level.

Study III focused on a sub-group of intoxicated patients in the ICU, their demographic profiles, presenting symptoms, drug concentration levels in blood as well as short- and long-term mortality. It is a common patient group, with similar background of psychiatric illness. Drug concentrations found in blood correlated to the substances suspected by clinicians. Most self-poisoned patients survive the individual ICU stay but they often reoccur, and 5-year mortality is substantial.

Study IV investigated blood concentrations of ten analgesic and sedative drugs, both before and after death. Blood samples were compared pre-mortem, peri-mortem and post-mortem when applicable. Fentanyl blood concentrations displayed a significant increase post-mortem on a group level.

In summary, this thesis contributes to the knowledge of analgesic and sedative drug dosages, clinical responses and measured blood concentrations in intensive care patients. It also shines a light on describing intoxicated patients, and changes in blood concentrations in patients that die during intensive care.