Selasa, 27 Januari 2009

Surface electrostimulation of acupuncture points for sedation of critically ill patients in the intensive care unit--a pilot study

By: Nayak, Sandeep,Wenstone, Richard,Jones, Andy,Nolan, Jill,Strong, Ann,Carson, Jeff

Abstract

Background This is a pilot study to investigate the effects of electrostimulation of acupuncture points on sedation and the dose of sedatives in the Intensive Care Unit. Methods Electrostimulation of acupuncture points was performed on 12 critically ill patients requiring sedation for mechanical ventilation. Electrostimulation was applied by point surface electrodes at LI4, ST36, HT7 and LR3 points for 20 minutes every hour for 12 hours using dense dispersed mode with a current frequency of 10-100Hz and maximum intensity of 10mA. All patients were sedated with propofol and alfentanil as required. The dose of propofol was reduced by 10mg/hour provided the patient remained sedated according to our guidelines. Sedation and analgesia scores, dose of sedative and analgesics drugs, respiratory rate, heart rate, mean arterial blood pressure and compliance with the ventilator were recorded before electrostimulation of acupuncture points, and hourly thereafter for 12 hours. Results There was significant reduction in the median propofol consumption from 145mg/hour (range 30250) to 15mg/hour (range 0-250) (P<0.05), without any significant change in sedation scores or analgesia scores. The haemodynamic and respiratory variables remained stable. All patients were compliant with the ventilator. Conclusion This pilot study showed significant reduction in the dose of propofol required for sedation in critically ill patients following surface electrostimulation of acupuncture points, without any adverse effects. A randomised controlled trial is warranted.

Keywords

Electrostimulation of acupuncture points, sedation, intensive care unit.

Introduction

Management of sedation of critically ill patients remains one of the challenging areas of practice in the intensive care unit (ICU). A variety of agents have been used. (1-4) Yet consensus on a preferred agent is lacking, (3-7) with contradictory results emerging from studies comparing different agents in terms of quality of sedation and cost efficiency. Poor quality of sedation and analgesia in critically ill patients would be regarded by many as unkind and potentially unsafe. Over-sedation with drugs has many undesirable effects such as difficulties in communicating with patients, respiratory depression, hypotension, ileus, renal failure, venous stasis and immunosuppression. (8;9) Under-sedation also has negative effects including pain, tachycardia, hypertension, and failure of patient-ventilator synchrony leading to hypoxemia. (8) In addition, sedatives and analgesic agents such as propofol and alfentanil, which are commonly used in different ICUs, are expensive. In view of the above side effects associated with under- or over-sedation by drugs it would be reasonable to suggest that the use of an alternative method for sedation should be considered.

One of the available methods for sedation, which does not rely on the use of drugs, is acupuncture. The use of non-pharmacological methods, such as acupuncture, for pain relief is well documented. (10;11) If successful, its use would offer sedation without the side effects associated with drugs. Its use for the relief of anxiety and withdrawal symptoms in drug and alcohol rehabilitation has also been reported. (10-13)

However, we know of no reports about its use for the purpose of sedation or relief of anxiety in the critically ill. Evidence from several randomised controlled trials supports the use of acupuncture in pain conditions, substance misuse, nausea and vomiting. Acupuncture is associated with a calming effect. (14) Acupuncture has been used as an adjunct for sedation during lithotripsy. (15) In one study, electroacupuncture was found to be an effective method for inducing sedation with analgesia without any demonstrable side effects. (16) Ulett reported that electroacupuncture to classic acupuncture points is associated with a deep calming effect. (17) In a prospective, randomised, placebo controlled, double blinded study, electroacupuncture was shown to reduce anxiety, discomfort, and demand for sedative drugs during colonoscopy. (18) The incidence of adverse events following acupuncture is minimal. (19;20) Acupuncture seems to be one of the safer forms of medical intervention, in skilled hands. Electrostimulation of acupuncture points using point surface electrodes avoids the adverse events associated with needles such as haemorrhage, transmitted infection and forgotten needles

We therefore undertook this pilot study to investigate whether surface electrostimulation of acupuncture points is a useful technique to supplement pharmacological agents used for sedation in critically ill patients. The objectives of this study were: to investigate whether surface electrostimulation of acupuncture points has a useful sedative effect; whether it would enable us to reduce the dose of pharmacological agents to sedate critically ill patients in the ICU; and to assess any undesirable effects.

Methods

This study was conducted after approval was given from the Local Research Ethics Committee, and informed written agreement was obtained from the patients' relatives, as all patients were sedated, intubated and ventilated. This was a pilot study to investigate the effectiveness of surface electrostimulation of acupuncture points and the within patient variability of the dose of sedative (propofol) used to sedate critically ill patients in our unit. Patient management in all other aspects of the subjects' illness remained the same.

All critically ill patients admitted to the ICU at the Royal Liverpool University Hospital who required sedation were considered for entry into the study. Those who were included were: patients whose relatives had given informed written agreement to enter the study; adults between 18 and 80 years of age; critically ill patients requiring sedation for mechanical ventilation. The patients who were excluded from this study were: pregnant women; patients with known cardiac valve disease; patients with cardiac pacemakers or hearing aid device in place; patients with head injury, status epilepticus, tetanus or acute respiratory distress syndrome.

Patients admitted to the study were sedated according to the unit's guidelines for sedation. (21) When sedation score (Sheffield sedation scale) was 2-3, a record was made of the dose of sedative and analgesic drug used at that time (baseline). All patients then received surface electrostimulation at standard points (LI4, HT7, ST36 and LR3). The skin was cleaned with alcohol wipes and a point locator (AcuMedic AM3D point locator) was used to identify the acupuncture points. After cleaning the skin with antiseptic solution, point surface electrodes (Unilect TM, 3M Health Care) were applied to the exact acupuncture points and secured to the skin with Mefix tape (Molnlycke Health Care Limited, Dunstable, Bedfordshire UK). The acupuncture apparatus (AcuMedic AM3D, Acumedic, London, UK) was then connected to the electrodes in pairs. The electrostimulation was used in the dense dispersed mode and the current frequency was 10-100Hz. Current intensity varied up to 10mA. The duration of electrostimulation was 20 minutes every hour for 12 hours.

After 10 minutes of electrostimulation, the dose of propofol was slowly reduced by 10mg every hour provided that the patient's sedation level allowed. The sedation level was assessed and the doses of sedative and analgesic drugs were recorded every hour by an independent nurse. Should any patient show signs of non-compliance with mechanical ventilation, instability that was attributed to lack of sedation or the electrostimulation, the dose of propofol was increased according to the sedation guidelines and at the clinician's discretion, to increase the patient's depth of sedation. The dose of propofol used and the sedation score were noted hourly and at each point of change of propofol. Also, any extra

boluses of either agent (sedatives or analgesics) were recorded.

Box 1 The Sheffield Sedation Scale (Laing, 1992) (21)

1. Awake level--At this level patients should be awake and oriented,
requiring minimal or no sedation. They should be self ventilating,
either via a face mask or through an endotracheal tube which they
are tolerating

2. Agitation--At this level patient is showing signs of agitation
and restlessness, compromising ventilation, oxygenation and general
condition

3. Optimum level (i) *--This level of sedation should be where the
patient is just asleep. The patient should respond to speech, and
to touch either by squeezing hand or by blinking. The patient may
require bolus sedation as well as background sedation cover prior
to handling during care, physiotherapy or any invasive procedures

4. Optimum level (ii)*--This level of sedation should be where the
patient is just asleep. The patient responds to speech, and to touch
either by squeezing hand or by blinking. The patient should also handle
well and tolerate care

5. Sluggish level--This level is where the patient has dull/sluggish
responses to any form of stimulation, ie glabellar tap, or on suction
through the endotracheal tube

6. Flat level--This level is when the patient is showing no signs of
response to stimulation of any kind

* This level of sedation which allows patients to tolerate treatments
and general nursing care, physiotherapy and suction without
compromising their ventilation or cardiovascular state

Box 2 Criteria for analgesia score

Appearance of patient Score

Writhing, sweating, and distressed--very severe 4
Strained facial expression--severe 3
Still with eyes closed and avoiding movement--moderate 2
Dozing or asleep--slight 1
No discomfort--nil 0

Haemodynamic variables such as heart rate, mean arterial pressure and central venous pressure were monitored and recorded. Also respiratory variables such as respiratory rate, arterial blood gases and compliance with mechanical ventilation were noted according to the guidelines. Any adverse reactions that were considered to be related to the electrostimulation were recorded. A record of all patients' age, sex, diagnosis and outcome was made, together with APACHE II (Acute Physiology and Chronic Health Evaluation II) score, which is one of the scoring systems designed to measure the severity of disease for patients admitted to the ICU. This is based on current physiological measurements, age and previous health conditions, and scores range from 0-71. Increasing score is associated with an increasing risk of hospital death.

The main outcome measures were a reduction in the dose of sedative agents and analgesic drugs, a reduction in the side effects attributed to sedative and analgesic agents (eg stress responses and hypotension due to oversedation). Statistical analysis was done using the Wilcoxon Signed Rank Test and a P value of <0.05 was considered statistically significant.

[FIGURE 1 OMITTED]

[FIGURE 2 OMITTED]

Results

Patient demography

The patients studied had a median age of 65.5 (range 51-80) years with a M:F ratio of 3:1, as shown in Table 1. The median APACHE II scores were 13.5 (9-23).

There was a significant reduction in median propofol consumption from 145mg/hour (range 30250) to 15mg/hour (range 0-250)(P<0.05), without any significant change in sedation scores or analgesia scores (Table 2). The median sedation scores increased marginally, and the median analgesia requirements also decreased slightly but not significantly. The median analgesia score decreased from 1 (range 0-3) to 0.5 (range 0-3) though this was not statistically significant. There was no statistically significant change in the physiological variables measured: heart rate, mean arterial pressure and respiration rate. Additional propofol boluses were given to cover various procedures when needed. The median total extra dose of propofol was 95mg/patient/12 hours (range 0-410mg).

Discussion

There is very little evidence on the use of electrostimulation of acupuncture points for sedation of critically ill patients in the intensive care unit. However, the role of acupuncture for sedation and analgesia is fairly well established. (11-18) Surface electrostimulation of acupuncture points is a relatively safe and effective method of sedation. This pilot study showed that surface electrostimulation of acupuncture points resulted in sedation in the critically ill patients in the ICU without any side effects.

The dose of propofol needed to sedate the patients in the ICU rises constantly. The aim of using electrostimulation of acupuncture points for sedation was to reduce the dose of sedative agents. We used surface electrostimulation of LI4, HT7, ST36 and LR3 points. These points have been used in the past for sedation and to relieve anxiety. (11;14) These points are easy to locate and are convenient to use in the ICU. Auricular acupuncture points have been used for relaxation and intraoperative anaesthetic reduction. (22,23) Ear points were avoided due to difficulty in accessing these in the critically ill. The mechanism of action is similar to acupuncture and may be related to the release of opioid neuropeptides in the central nervous system.

We included a mix of medical and surgical patients as shown in Table 1, to study the effects of electrostimulation of acupuncture points in different groups of patients. Sedation score of 2-3 was usually achieved within 24 hours of admission and thus electrostimulation started. There was a significant reduction in median propofol consumption from 145mg/hour (range 30-250) to 15mg/hour (range 0-250)(P<0.05), without any significant change in sedation scores or analgesia scores, demonstrating that the patients were well sedated during the period of electrostimulation despite the decrease in propofol dose. This could be attributed to the sedative effects of electrostimulation of acupuncture points.

Although we had no control group, because this was a pilot study, the patients acted as their own control with regards to the dose of sedation before and after electrostimulation. There is no reason to believe that the reduction in dose of propofol could be partly due to the greater attention paid by the ICU nurses during the study period as the nurses administered propofol according to the sedation state of the patient as per the validated Sheffield sedation score and not to the use of acupuncture. From the propofol data (Table 3), the dose of propofol was sometimes reduced at a rate greater than 10mg/hour. This dose was based on the patient's condition and how well he or she was responding. Apart from the provision of the protocol and the consultant on call (independently from the researchers), this dose was entirely at the nurses' discretion. There seems to have been a dramatic reduction in the propofol requirement in 6 out of the 12 patients where propofol was completely switched off and sedation was maintained with electrostimulation only. There was a small reduction in propofol requirement in five patients, and no reduction in one. This variation in response to electrostimulation was neither related to any particular type of patient, nor to the dose of analgesic such as alfentanil. No other concomitant analgesics were used during the study period, and the dose of analgesics was also reduced.

During the study, we did not record the number of relatives who refused to give permission to enrol a patient into the study. However, some of the patients (or their relatives) who had electroacupuncture wanted us to continue after the 12 hours duration of the trial because their condition was much better than when they were on 'drug sedation'. The patients were not from any one particular diagnostic group.

The recognised limitations of this pilot study were the small number of patients recruited and the possibility that the other causes of altered consciousness such as sepsis could not be ruled out. However, all patients were relatively stable and were not on any ionotropic drugs. None of these patients had any renal or hepatic dysfunction which could have caused altered levels of consciousness--though this was an incidental observation and not part of the inclusion or exclusion criteria. We wanted to include patients who needed to have sedation because they needed to have controlled ventilation. The unit routinely uses sedation breaks in all patients to avoid excessive use of sedatives. There was a reduction in the analgesic requirement (alfentanil) though this was not statistically significant. There was minimal variation in the heart rate, respiratory rate and the mean arterial pressure, which shows that the patients were haemodynamically stable and were adequately sedated and pain-free. All patients were compliant with the ventilator. Another limitation of this study was that we did not record the requirement for propofol after the electrostimulation was switched off. However, it can be stated anecdotally that electrostimulation of acupuncture points helped in weaning patients off sedation and ventilation.

Minor discomfort may occur at stimulation sites if electrode gel dries out. To avoid this, sites were regularly inspected by the attending nurse and moistened whenever necessary. The serious events associated with electroacupuncture are usually associated with the use of needles and are related to poor practice and bad hygiene, (10;19;20) but these are unlikely to be caused by surface electrodes. No serious adverse effects were noted. Since the patients were sedated and were unable to indicate the level of stimulation, we chose the lowest level of current on the machine to avoid applying a painful stimulus. Dense dispersed mode was used, which alternates dense (high frequency) and dispersed (lower frequency) frequencies every three seconds. This mode produces less tolerance and less discomfort, and is considered to give better therapeutic results than a single frequency. A monophasic square wave form was used as it reaches the peak rapidly and has a relatively long plateau used to stimulate acupuncture points. Application of electrostimulation for 20 minutes every hour was not a logistical problem in this setting because of the one to one patient/nurse ratio in the ICU. We wanted to give sufficient stimulation to ensure that the patients were adequately sedated with electroacupuncture.

Abstract

Background This is a pilot study to investigate the effects of electrostimulation of acupuncture points on sedation and the dose of sedatives in the Intensive Care Unit. Methods Electrostimulation of acupuncture points was performed on 12 critically ill patients requiring sedation
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for mechanical ventilation. Electrostimulation was applied by point surface electrodes at LI4, ST36, HT7 and LR3 points for 20 minutes every hour for 12 hours using dense dispersed mode with a current frequency of 10-100Hz and maximum intensity of 10mA. All patients were sedated with propofol and alfentanil as required. The dose of propofol was reduced by 10mg/hour provided the patient remained sedated according to our guidelines. Sedation and analgesia scores, dose of sedative and analgesics drugs, respiratory rate, heart rate, mean arterial blood pressure and compliance with the ventilator were recorded before electrostimulation of acupuncture points, and hourly thereafter for 12 hours. Results There was significant reduction in the median propofol consumption from 145mg/hour (range 30250) to 15mg/hour (range 0-250) (P<0.05), without any significant change in sedation scores or analgesia scores. The haemodynamic and respiratory variables remained stable. All patients were compliant with the ventilator. Conclusion This pilot study showed significant reduction in the dose of propofol required for sedation in critically ill patients following surface electrostimulation of acupuncture points, without any adverse effects. A randomised controlled trial is warranted.

Keywords

Electrostimulation of acupuncture points, sedation, intensive care unit.

Introduction

Management of sedation of critically ill patients remains one of the challenging areas of practice in the intensive care unit (ICU). A variety of agents have been used. (1-4) Yet consensus on a preferred agent is lacking, (3-7) with contradictory results emerging from studies comparing different agents in terms of quality of sedation and cost efficiency. Poor quality of sedation and analgesia in critically ill patients would be regarded by many as unkind and potentially unsafe. Over-sedation with drugs has many undesirable effects such as difficulties in communicating with patients, respiratory depression, hypotension, ileus, renal failure, venous stasis and immunosuppression. (8;9) Under-sedation also has negative effects including pain, tachycardia, hypertension, and failure of patient-ventilator synchrony leading to hypoxemia. (8) In addition, sedatives and analgesic agents such as propofol and alfentanil, which are commonly used in different ICUs, are expensive. In view of the above side effects associated with under- or over-sedation by drugs it would be reasonable to suggest that the use of an alternative method for sedation should be considered.

One of the available methods for sedation, which does not rely on the use of drugs, is acupuncture. The use of non-pharmacological methods, such as acupuncture, for pain relief is well documented. (10;11) If successful, its use would offer sedation without the side effects associated with drugs. Its use for the relief of anxiety and withdrawal symptoms in drug and alcohol rehabilitation has also been reported. (10-13)

However, we know of no reports about its use for the purpose of sedation or relief of anxiety in the critically ill. Evidence from several randomised controlled trials supports the use of acupuncture in pain conditions, substance misuse, nausea and vomiting. Acupuncture is associated with a calming effect. (14) Acupuncture has been used as an adjunct for sedation during lithotripsy. (15) In one study, electroacupuncture was found to be an effective method for inducing sedation with analgesia without any demonstrable side effects. (16) Ulett reported that electroacupuncture to classic acupuncture points is associated with a deep calming effect. (17) In a prospective, randomised, placebo controlled, double blinded study, electroacupuncture was shown to reduce anxiety, discomfort, and demand for sedative drugs during colonoscopy. (18) The incidence of adverse events following acupuncture is minimal. (19;20) Acupuncture seems to be one of the safer forms of medical intervention, in skilled hands. Electrostimulation of acupuncture points using point surface electrodes avoids the adverse events associated with needles such as haemorrhage, transmitted infection and forgotten needles

We therefore undertook this pilot study to investigate whether surface electrostimulation of acupuncture points is a useful technique to supplement pharmacological agents used for sedation in critically ill patients. The objectives of this study were: to investigate whether surface electrostimulation of acupuncture points has a useful sedative effect; whether it would enable us to reduce the dose of pharmacological agents to sedate critically ill patients in the ICU; and to assess any undesirable effects.

Methods

This study was conducted after approval was given from the Local Research Ethics Committee, and informed written agreement was obtained from the patients' relatives, as all patients were sedated, intubated and ventilated. This was a pilot study to investigate the effectiveness of surface electrostimulation of acupuncture points and the within patient variability of the dose of sedative (propofol) used to sedate critically ill patients in our unit. Patient management in all other aspects of the subjects' illness remained the same.

All critically ill patients admitted to the ICU at the Royal Liverpool University Hospital who required sedation were considered for entry into the study. Those who were included were: patients whose relatives had given informed written agreement to enter the study; adults between 18 and 80 years of age; critically ill patients requiring sedation for mechanical ventilation. The patients who were excluded from this study were: pregnant women; patients with known cardiac valve disease; patients with cardiac pacemakers or hearing aid device in place; patients with head injury, status epilepticus, tetanus or acute respiratory distress syndrome.

Patients admitted to the study were sedated according to the unit's guidelines for sedation. (21) When sedation score (Sheffield sedation scale) was 2-3, a record was made of the dose of sedative and analgesic drug used at that time (baseline). All patients then received surface electrostimulation at standard points (LI4, HT7, ST36 and LR3). The skin was cleaned with alcohol wipes and a point locator (AcuMedic AM3D point locator) was used to identify the acupuncture points. After cleaning the skin with antiseptic solution, point surface electrodes (Unilect TM, 3M Health Care) were applied to the exact acupuncture points and secured to the skin with Mefix tape (Molnlycke Health Care Limited, Dunstable, Bedfordshire UK). The acupuncture apparatus (AcuMedic AM3D, Acumedic, London, UK) was then connected to the electrodes in pairs. The electrostimulation was used in the dense dispersed mode and the current frequency was 10-100Hz. Current intensity varied up to 10mA. The duration of electrostimulation was 20 minutes every hour for 12 hours.

After 10 minutes of electrostimulation, the dose of propofol was slowly reduced by 10mg every hour provided that the patient's sedation level allowed. The sedation level was assessed and the doses of sedative and analgesic drugs were recorded every hour by an independent nurse. Should any patient show signs of non-compliance with mechanical ventilation, instability that was attributed to lack of sedation or the electrostimulation, the dose of propofol was increased according to the sedation guidelines and at the clinician's discretion, to increase the patient's depth of sedation. The dose of propofol used and the sedation score were noted hourly and at each point of change of propofol. Also, any extra

boluses of either agent (sedatives or analgesics) were recorded.

Box 1 The Sheffield Sedation Scale (Laing, 1992) (21)

1. Awake level--At this level patients should be awake and oriented,
requiring minimal or no sedation. They should be self ventilating,
either via a face mask or through an endotracheal tube which they
are tolerating

2. Agitation--At this level patient is showing signs of agitation
and restlessness, compromising ventilation, oxygenation and general
condition

3. Optimum level (i) *--This level of sedation should be where the
patient is just asleep. The patient should respond to speech, and
to touch either by squeezing hand or by blinking. The patient may
require bolus sedation as well as background sedation cover prior
to handling during care, physiotherapy or any invasive procedures

4. Optimum level (ii)*--This level of sedation should be where the
patient is just asleep. The patient responds to speech, and to touch
either by squeezing hand or by blinking. The patient should also handle
well and tolerate care

5. Sluggish level--This level is where the patient has dull/sluggish
responses to any form of stimulation, ie glabellar tap, or on suction
through the endotracheal tube

6. Flat level--This level is when the patient is showing no signs of
response to stimulation of any kind

* This level of sedation which allows patients to tolerate treatments
and general nursing care, physiotherapy and suction without
compromising their ventilation or cardiovascular state

Box 2 Criteria for analgesia score

Appearance of patient Score

Writhing, sweating, and distressed--very severe 4
Strained facial expression--severe 3
Still with eyes closed and avoiding movement--moderate 2
Dozing or asleep--slight 1
No discomfort--nil 0

Haemodynamic variables such as heart rate, mean arterial pressure and central venous pressure were monitored and recorded. Also respiratory variables such as respiratory rate, arterial blood gases and compliance with mechanical ventilation were noted according to the guidelines. Any adverse reactions that were considered to be related to the electrostimulation were recorded. A record of all patients' age, sex, diagnosis and outcome was made, together with APACHE II (Acute Physiology and Chronic Health Evaluation II) score, which is one of the scoring systems designed to measure the severity of disease for patients admitted to the ICU. This is based on current physiological measurements, age and previous health conditions, and scores range from 0-71. Increasing score is associated with an increasing risk of hospital death.

The main outcome measures were a reduction in the dose of sedative agents and analgesic drugs, a reduction in the side effects attributed to sedative and analgesic agents (eg stress responses and hypotension due to oversedation). Statistical analysis was done using the Wilcoxon Signed Rank Test and a P value of <0.05 was considered statistically significant.

[FIGURE 1 OMITTED]

[FIGURE 2 OMITTED]

Results

Patient demography

The patients studied had a median age of 65.5 (range 51-80) years with a M:F ratio of 3:1, as shown in Table 1. The median APACHE II scores were 13.5 (9-23).

There was a significant reduction in median propofol consumption from 145mg/hour (range 30250) to 15mg/hour (range 0-250)(P<0.05), without any significant change in sedation scores or analgesia scores (Table 2). The median sedation scores increased marginally, and the median analgesia requirements also decreased slightly but not significantly. The median analgesia score decreased from 1 (range 0-3) to 0.5 (range 0-3) though this was not statistically significant. There was no statistically significant change in the physiological variables measured: heart rate, mean arterial pressure and respiration rate. Additional propofol boluses were given to cover various procedures when needed. The median total extra dose of propofol was 95mg/patient/12 hours (range 0-410mg).

Discussion

There is very little evidence on the use of electrostimulation of acupuncture points for sedation of critically ill patients in the intensive care unit. However, the role of acupuncture for sedation and analgesia is fairly well established. (11-18) Surface electrostimulation of acupuncture points is a relatively safe and effective method of sedation. This pilot study showed that surface electrostimulation of acupuncture points resulted in sedation in the critically ill patients in the ICU without any side effects.

The dose of propofol needed to sedate the patients in the ICU rises constantly. The aim of using electrostimulation of acupuncture points for sedation was to reduce the dose of sedative agents. We used surface electrostimulation of LI4, HT7, ST36 and LR3 points. These points have been used in the past for sedation and to relieve anxiety. (11;14) These points are easy to locate and are convenient to use in the ICU. Auricular acupuncture points have been used for relaxation and intraoperative anaesthetic reduction. (22,23) Ear points were avoided due to difficulty in accessing these in the critically ill. The mechanism of action is similar to acupuncture and may be related to the release of opioid neuropeptides in the central nervous system.

[FIGURE 3 OMITTED]

We included a mix of medical and surgical patients as shown in Table 1, to study the effects of electrostimulation of acupuncture points in different groups of patients. Sedation score of 2-3 was usually achieved within 24 hours of admission and thus electrostimulation started. There was a significant reduction in median propofol consumption from 145mg/hour (range 30-250) to 15mg/hour (range 0-250)(P<0.05), without any significant change in sedation scores or analgesia scores, demonstrating that the patients were well sedated during the period of electrostimulation despite the decrease in propofol dose. This could be attributed to the sedative effects of electrostimulation of acupuncture points.

Although we had no control group, because this was a pilot study, the patients acted as their own control with regards to the dose of sedation before and after electrostimulation. There is no reason to believe that the reduction in dose of propofol could be partly due to the greater attention paid by the ICU nurses during the study period as the nurses administered propofol according to the sedation state of the patient as per the validated Sheffield sedation score and not to the use of acupuncture. From the propofol data (Table 3), the dose of propofol was sometimes reduced at a rate greater than 10mg/hour. This dose was based on the patient's condition and how well he or she was responding. Apart from the provision of the protocol and the consultant on call (independently from the researchers), this dose was entirely at the nurses' discretion. There seems to have been a dramatic reduction in the propofol requirement in 6 out of the 12 patients where propofol was completely switched off and sedation was maintained with electrostimulation only. There was a small reduction in propofol requirement in five patients, and no reduction in one. This variation in response to electrostimulation was neither related to any particular type of patient, nor to the dose of analgesic such as alfentanil. No other concomitant analgesics were used during the study period, and the dose of analgesics was also reduced.

During the study, we did not record the number of relatives who refused to give permission to enrol a patient into the study. However, some of the patients (or their relatives) who had electroacupuncture wanted us to continue after the 12 hours duration of the trial because their condition was much better than when they were on 'drug sedation'. The patients were not from any one particular diagnostic group.

The recognised limitations of this pilot study were the small number of patients recruited and the possibility that the other causes of altered consciousness such as sepsis could not be ruled out. However, all patients were relatively stable and were not on any ionotropic drugs. None of these patients had any renal or hepatic dysfunction which could have caused altered levels of consciousness--though this was an incidental observation and not part of the inclusion or exclusion criteria. We wanted to include patients who needed to have sedation because they needed to have controlled ventilation. The unit routinely uses sedation breaks in all patients to avoid excessive use of sedatives. There was a reduction in the analgesic requirement (alfentanil) though this was not statistically significant. There was minimal variation in the heart rate, respiratory rate and the mean arterial pressure, which shows that the patients were haemodynamically stable and were adequately sedated and pain-free. All patients were compliant with the ventilator. Another limitation of this study was that we did not record the requirement for propofol after the electrostimulation was switched off. However, it can be stated anecdotally that electrostimulation of acupuncture points helped in weaning patients off sedation and ventilation.

Minor discomfort may occur at stimulation sites if electrode gel dries out. To avoid this, sites were regularly inspected by the attending nurse and moistened whenever necessary. The serious events associated with electroacupuncture are usually associated with the use of needles and are related to poor practice and bad hygiene, (10;19;20) but these are unlikely to be caused by surface electrodes. No serious adverse effects were noted. Since the patients were sedated and were unable to indicate the level of stimulation, we chose the lowest level of current on the machine to avoid applying a painful stimulus. Dense dispersed mode was used, which alternates dense (high frequency) and dispersed (lower frequency) frequencies every three seconds. This mode produces less tolerance and less discomfort, and is considered to give better therapeutic results than a single frequency. A monophasic square wave form was used as it reaches the peak rapidly and has a relatively long plateau used to stimulate acupuncture points. Application of electrostimulation for 20 minutes every hour was not a logistical problem in this setting because of the one to one patient/nurse ratio in the ICU. We wanted to give sufficient stimulation to ensure that the patients were adequately sedated with electroacupuncture.

Propofol is one of the ten most expensive drugs used in the ICU according to the Intensive Care National Working Group on Costing. (24) The reduction in propofol requirement for sedation, following acupuncture was significant. This could result in a significant overall reduction in the cost of sedatives used in ICUs.

In conclusion, this study showed that electrostimulation of acupuncture points was associated with improved sedation of critically ill patients and a significant reduction in the dose of propofol without significant change in sedation and analgesic scores. Electrostimulation of acupuncture points might be beneficial as an alternative form of sedation to reduce dose of sedatives agents and reduce the side effects of large doses of sedative drugs; it might prove to be beneficial in weaning critically ill patients. This was a pilot study and a randomised controlled study is now warranted.

Acknowledgment

The authors would like to thank Dr S M Mostafa (Retired Consultant in Anaesthesia and Intensive Care, Royal Liverpool University Hospital) for his efforts in setting up and conducting this project and also the AICRE Trust for financial help. We would also like to thank the staff of the Intensive Care Unit, Royal Liverpool University Hospital for their help.

Conflict of Interest None declared.

Summary points

Adequate sedation of critically ill patients on ventilators is crucial but problematic In this study, twelve critically ill patients were repeatedly given electrostimulation at acupuncture points, and their need for sedative drugs was reduced

Reference list

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(2.) Riker RR, Fraser GL, Cox PM. Continuous infusion of haloperidol controls agitation in critically ill patients. Crit Care Med 1994;22(3):433-40.

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Correspondence: Sandeep Nayak drsnayak@yahoo.co.uk

Sandeep Nayak, Richard Wenstone, Andy Jones, Jill Nolan, Ann Strong, Jeff Carson

Sandeep Nayak : specialist registrar in anaesthesia
Richard Wenstone : consultant in anaesthesia & intensive care
Andy Jones : consultant in anaesthesia
Jill Nolan : research nurse
Ann Strong : research nurse
Jeff Carson : research nurse

Intensive Care Unit, Royal Liverpool University Hospital, Liverpool, UK


Table 1 Characteristics and diagnoses of the 12 patients
who received electrostimulation

Median age in years (range) 65.5 (51-80)
Sex (n; M:F) 9:3
Median APACHE II score (range) 13.5 (9-23)
Diagnoses (n)
Abdominal aortic aneurysm repair 2
Necrotising pancreatitis 2
Major trauma 2
Major intra abdominal surgery 4
Chronic obstructive pulmonary disease 2

Table 2 The variables measured in this study, expressed
as median (range)

Variable Baseline 12 hours post P value
acupuncture

Propolol mg/hour 145 (30-250) 15 (0-250) 0.(X)5
Allentanil tng/hour 1 (0-3) 0.5(0-3) 0.255
Sedation score 3 (2-5) 3.30-5) 0.28
Analgesia score 1 (0-3) 0.5(0-3) 0.255
Fleart rate heat/minute 86 (70-117) 87(57-121) 0.455

Mean Arterial
Pressure in mm Hg 91 (62-109) 90(63-127) 0.209
Respiration rate
breath/minute 16.5 (12-31) 19(2-33) 0.624

Table 3 The hourly requirement of propofol in mg/hour for
sedation for individual patients during the 12 hours of
electrostimulation

Patient 0 1 2 3 4 5 6

1 40 40 0 0 0 0 0
2 100 100 90 80 70 60 50
3 190 190 190 190 250 190 150
4 100 100 120 120 120 120 120
5 140 150 150 50 50 50 50
6 150 150 130 130 130 120 120
7 250 230 220 210 200 220 200
8 250 250 240 230 220 210 200
9 250 250 250 250 250 250 250
10 50 40 40 40 40 40 40
11 30 30 20 20 30 30 30
12 250 230 210 150 120 90 0

Patient 7 8 9 10 11 12

1 0 0 0 0 0 0
2 40 30 20 20 10 0
3 100 50 0 0 0 0
4 100 100 100 90 80 70
5 50 0 0 0 0 0
6 120 100 110 80 100 100
7 190 190 190 190 200 250
8 190 180 200 200 200 200
9 250 250 250 220 220 220
10 30 0 20 10 0 0
11 30 30 30 30 30 30
12 0 0 0 0 0 0

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