Sedation in the post-anaesthesia care unit

Correspondence to: Andrius Macas, Department of Anesthe­ siology and Intensive Care, Lithuanian University of Health Sciences, Eivenių 2, LT­50028 Kaunas, Lithuania. E­mail: andrius.macas@kmuk.lt Background. Post­anaesthetic sedation is a common practice as it pro­ vides greater comfort and psychological stability for patients. Some spe­ cialists claim that sedation in the post­anaesthetic care unit (PACU) is applied too seldom due to several reasons. The goal of this study is to evaluate sedation in PACU in several aspects. Materials and methods. A total of 299 patients admitted to the PACU after general, orthopedic­traumatologic or urologic surgical procedures were enrolled in this prospective study. The patients evaluated their qual­ ity of sleep and the worst intensity of pain experienced in PACU, which was assessed using the Numerical Rating Scale. Nurses evaluated sedation using the Motor Activity Assessment Scale and filled in the questionnaire about the importance of sedation. Results. Statistically significant difference was observed in the quality of sleep between the patients sedated using benzodiazepines and opioids together and non­sedated patients (p = 0.025). There is no considerable difference in the statistics concerning the behavior of the patients. The patients prescribed only with opioids IV or IM, as well as the patients prescribed with opioids together with benzodiazepines, feel less intense pain compared to the non­sedated patients (p = 0.016, p = 0.03). Accord­ ing to the personnel, sedation is necessary in PACU. Half of them think that patients prescribed with opioids need additional sedation. Conclusions. Sedation is necessary in PACU. This fact is evident in the statistically significant difference of comfort factors among the patients as well as in the opinion of the nursing personnel that spend most of the time communicating and caring about the comfort of the patients.


INTRODUCTION
Postanaesthetic sedation has been a common practice all over the world for many years.It pro vides greater comfort and psychological stability for patients.
Lack of sedation in this period may lead to postoperative agitation, anxiety, increased post operative pain perception and prolonged stay in PACU (postanaesthesia care unit), ICU (intensive care unit) and the hospital itself (1).It may also increase the risk of patient's selfinjury (2) and complicate the provision of adequate patient care.
There are opinions that benzodiazepines can re duce the need of opioid analgesics in the period of postanaesthesia.Pain is a subjective experi ence, and stress, as well as psychological condi tion, cause more intense postoperative perception of pain (3).The study shows that patients who felt anxiety before the operation and expected to feel pain after the procedure experienced higher degree of pain (4,5).The emphasis on forthcoming pain influences longer postoperative recovery, increases the need of painkillers and prolongs the period of hospitalization (3).Benzodiazepines have no an algesic effect, however, due to the anxiety reliev ing, tranquilising and muscle relaxing effect, they decrease the perception of pain and prevent from further pain caused by anxiety (6).
Some specialists claim that sedation in the post anaesthetic ward is applied too seldom.Possible reasons are given below.
Groups of medications most commonly used for sedation can cause postoperative delirium.The researches have revealed that a method of anaes thesia (regional or general) and related medications do not influence postoperative delirium (7,8).Opi nions are diverse and the systematic review carried out by the authors on this issue does not indicate clearly that benzodiazepines could cause postoper ative delirium (9).Postoperative delirium possibly caused by the usage of benzodiazepines depends on the dose: big doses provoke post operative delirium more often compared with small doses (10).In some cases benzodiazepines are used for the treat ment of postoperative delirium (11,12).Opioids are referred to as the risk factor for delirium to ap pear.The systematic review carried out by the au thors did not prove it categorically (9).The study showed that in case of severe pain the avoidance of opioids or prescription of small doses are related with higher risk of delirium (13).
Medications that are used for sedation can cause disorders of cognitive functions.It is diffi cult to evaluate objectively the impact on cognitive functions since pain itself as well as anxiety can have a negative effect.That is why it is complicated to assess the role of medications at this point (14).The shortterm disorders of cognitive functions provoked by benzodiazepines include anterograde amnesia, fluency of speech, psychomotor speed, time of reaction, coordination and focus of atten tion, semantic memory, etc.It is difficult to com pare the results of the studies performed on this issue since different medications and techniques were used (15).Negative effects of big doses and long term usage of opioids on cognitive functions were mentioned in literature a long time ago (16).Oneoff doses or prescription of average or small doses for a very short period effect cognitive func tions in a different way, depending on doses and different types of opioids (17).Some surveys point out that opioids can even improve cognitive func tions (18).
The need for sedation in PACU is difficult to as sess because there is no uniform sedation policy: there are no standardized recommendations for the use of specific scales or criteria, no recommen dations for a targeted therapeutic level of sedation according to patient's specific needs and specific indications.The same problem arises in further assessment of the patient's level of sedation after the sedative medications have been appointed.In order to avoid complications due to oversedation and negative impact on morbidity, mortality and functional recovery of a patient, a reliable tool to monitor sedation in PACU is essential (19), as oversedation itself increases the risk of depres sive symptoms, delirium and delusional memories (20).Therefore, the decision on whether a patient requires sedation or not, is more intuitive than ob jective and depends on the nurses' personal assess ment, the level of experience and education they have, support or directions from other medical staff, the subjective understanding of reasonable comfort (21).There are some other no less signifi cant factors that can affect both the frequency of sedation and sedation level, such as the staff 's will ingness to work in a quiet environment especially during the night shifts or the number of staff on duty (21).Another multicentre study showed that nurses take the agitated patients seriously, but they encounter difficulties in assessing the severity of the patient's condition and deciding whether they should inform the doctor that the patient requires sedation or should wait patiently (22).In this case nurses are the key personnel and their attitude and behaviour has a great impact on the process of ad ministration of sedation (23).
The authors of the present study have taken a decision to carry out a research evaluating sedation in the postoperative ward in several aspects.The frequency of sedation and medications most often used for sedation have been assessed.At the same time the quality of sleep, behavior and pain percep tion among sedated (using different methods) and nonsedated patients have been compared.And fi nally, the position of the personnel evaluating the postoperative sedation and its need has been ascer tained.

MATERIALS AND METHODS
This prospective study was conducted during the period of 2 months (1 December 2011 -31 Janu ary 2012) in postanaesthesia care units (PACU) of General Surgery and OrthopaedicTraumatology Departments, Hospital of Lithuanian University of Health Sciences Kaunas Clinics.Every patient admitted to PACU after general surgical, orthopae dictraumatologic or urologic surgical procedures and who spent a night there was included in this prospective study.The general data about the pa tient (age, weight, medical history and diagnosis, type of surgery, ASA score, the date of surgery and the exact time of admission to PACU) were taken from the casehistories.In the morning patients themselves evaluated their quality of sleep and the worst intensity of pain experienced during their stay in PACU.In order to evaluate their quality of sleep patients had to choose one answer from the following: (a) I slept very well, (b) I slept fine, but I was awake for a couple of times during the night, (c) I slept badly, (d) I couldn't sleep at all.
The intensity of pain was assessed using the Numerical Rating Scale (NRS) (24).The nurses evaluated sedation using the Motor Activity As sessment Scale (MAAS) (25).Additionally, the nurses anonymously filled in the questionnaire about the importance of sedation in general in PACU.The questionnaire consisted of the fol lowing questions: (a) Does sedation play an im portant role in PACU? (Yes, No); (b) What are the most popular indications to sedate in PACU?(c) Which sedative medications do you usually use in PACU?(d) Do the patients receiving opi oids for analgesia need additional sedative?Sta tistical analysis was performed using SPSS 17.0.As the variables were not normally distributed, KruskalWallis and MannWhitney U tests were used.P < 0.05 was considered to be a statistically significant difference.This study was approved by the Bioethics Centre of the Lithuanian University of Health Sciences (BCMF156).
To determine if sleep quality, pain intensity by NRS and sedation score by MAAS differed sig nificantly among all 5 groups, the nonparametric KruskalWallis test was used.When comparing groups in pairs, the nonparametric MannWhit ney test was used.The quality of sleep among all the groups did not differ significantly, however, comparing groups in pairs, there was a statisti cally significant difference between the 4th and 5th group (p = 0.025).Patient sedation by MAAS cannot be evaluated statistically, because in the KruskalWallis test application it is required that all the values of the MAAS scale obtained at least 5 cases (see Figure ).
Pain intensity by NRS was not statistically sig nificantly different among all five groups, but com paring in pairs, there was a significant difference between the 3rd and 5th group (p = 0.016), 4th and 5th group (p = 0.03).All 15 nurses, who filled in the questionnaire, thought that sedation was required.The most com mon causes of sedation, such as agitation was men tioned 12 times, insomnia 10 times and patient preference 8 times.The medications used to sedate according to frequency were as follows: diazepam was mentioned 14 times, midazolam 12 times, halo peridol 5 times, tiapridal 3 times.2 nurses (13%) thought that patients who received opioids should be additionally sedated, 7 nurses (47%) thought that it was not necessary and 6 nurses (40%) thought that sometimes additional sedation was necessary.

DISCUSSION
Most of the patients in postanaesthesia care units are sedated.Most common medications used for sedation, as described in literature, are benzodi azepines and opioids.Statistically significant dif ference can be observed in the quality of sleep be tween the patients sedated using benzodiazepines and opioids together and nonsedated patients.There is no considerable difference in the statistics concerning the behaviour of the groups of patients.The difference cannot be evaluated due to insuffi cient scope and uneven distribution.According to the data in the Figure, the values MAAS 1, MAAS 5 and MAAS 6 obtained less than 5 cases and the sta tistical analysis using the KruskalWallis test could not be performed.The patients using only pre scription opioids IV or IM, as well as the patients using prescription opioids together with benzodia zepines, feel less intense pain compared with the nonsedated patients.According to the personnel, sedation is necessary in the postanaesthesia care unit.Half of them think that the patients that use prescribed opioids need additional sedation.Since nurses are an important element in the sedation chain, it would be reasonable to carry out a more thorough survey and evaluate their competence in this field and comprehension of sedation.Moreo ver, a research on possible disorders of cognitive functions in the postanaesthesia care unit should also be carried out as there are very few studies on this issue.However, it is also important to estimate the oversedation frequency in the postanaesthe sia care unit in order to improve the quality of se dation having in mind the reasons and relevance of the problem.

CONCLUSIONS
Sedation is necessary in PACU.This fact is evident in the statistically significant difference in comfort factors among the patients as well as in the opin ion of the nursing personnel that spend most of the time communicating and caring of the comfort of the patients.

Table . 5
groups of patients according to medication used for sedation