Analysis of Complaints from Patients During Mechanical Ventilation After Cardiac Surgery: A Retrospective Study Yi Wang, BS, Hua Li, MS, Honglin Zou, BS, and Yaxiong Li, BS Objectives: This study analyzed major complaints from patients during mechanical ventilation after cardiac surgery and identified the most common complaints to reduce adverse psychologic responses. Design: Retrospective. Setting: A single tertiary university hospital. Participants: Patients with heart disease who were on mechanical ventilation after cardiac surgery (N ¼ 800). Interventions: The major complaints of the patients during mechanical ventilation after cardiac surgery were analyzed. Measurements and Main Results: Patients’ comfort was evaluated using a visual analog scale, and the factors affecting comfort were analyzed. The average visual analog scale score in all patients was 5.8 ⫾ 2.0, and most patients presented moderate discomfort. The factors affecting
comfort included dry mouth, thirst, tracheal intubation, aspiration of sputum, communication barriers, limited mobility, fear/anxiety, patient-ventilator dyssynchrony, and poor environmental conditions. Of these factors, 8 were independent predictors of the visual analog scale score. Patients considered mechanical ventilation to be the worst part of their hospitalization. Conclusions: The study identified 8 independent factors causing discomfort in patients during mechanical ventilation after cardiac surgery. Clinicians should take appropriate measures and implement nursing interventions to reduce suffering, physical and psychologic trauma, and adverse psychologic responses and to promote recovery. & 2015 Elsevier Inc. All rights reserved.
M
spontaneous breathing trial; (6) was able to communicate with the hospital staff, and communication was not limited because of the use of a specific dialect or low education level; and (7) without any complications.
ECHANICAL VENTILATION is often necessary for patients with complicated postoperative treatment and respiratory dysfunction after cardiac surgery.1 Although methods vary among countries and centers, many patients need mechanical ventilation during and sometimes after cardiac surgery,2 and this is costly and uncomfortable for the patients. During ventilation, it is always difficult for patients to communicate with the medical staff. Their complaints cannot be handled correctly, which causes a painful experience for the patients and can have a negative impact on their recovery.3 The authors hypothesize that specific factors are responsible for the discomfort of mechanical ventilation. The authors performed a retrospective investigation of the major complaints of a group of patients with heart disease during mechanical ventilation after surgery. The aim of the present study is to summarize the physiologic and psychological needs of patients during mechanical ventilation. Analysis of patients’ comfort was performed using a visual analog scale (VAS), which is a psychometric scale for subjective characteristics that cannot be directly measured and used in postoperative pain analysis.4 The authors’ specially created survey with VAS is presented in Appendix A. This study may help medical personnel carry out treatments and medical care specifically to reduce the suffering caused by discomfort of mechanical ventilation.
KEY WORDS: cardiac surgery, comfort, ventilator, ICU
Clinical Techniques
METHODS
Anesthesia was induced using intravenous midazolam, 0.1 mg/kg; etomidate, 0.2 to 0.4 mg/kg; sufentanil, 0.5 to 1 mg/kg; and vecuronium bromide, 0.08 to 0.12 mg/kg. Orotracheal intubation was performed, and an anesthesia machine was connected for mechanical ventilation. Initial parameters were tidal volume of 8 to 10 mL/kg, respiratory frequency of 10 to 15 breaths/min, inspiratory/expiratory ratio of 1:2, and fraction of inspired oxygen of 60%. The parameters were adjusted according to the individual situation to obtain a satisfactory result of mechanical ventilation. For anesthesia maintenance, sufentanil, 0.3 to 1.0 mg/kg/h, was intravenously infused, sevoflurane, 1.5% to 2.5%, was inhaled, and a single dose of vecuronium bromide, 0.1 to 0.3 mg/kg, was administered (repeat dosing was allowed at minimal intervals of 45 min). Moderate hypothermic cardiopulmonary bypass was performed. After surgery, the mechanical ventilation mode was bilevel positive airway pressure, with parameters set for most patients as follows: pressure of 15 cmH2O, positive end-expiratory pressure of 5 cmH2O, and sensitivity of 2 L/min (Evita 4;
This retrospective study was performed in 800 consecutive patients who underwent cardiovascular surgery from January 2009 to December 2012 at the authors’ hospital. The study was approved by the ethical committee of the hospital, and the need for individual patient consent was waived by the committee. Inclusion criteria were as follows: (1) 418 years old; (2) underwent open cardiac surgery under direct vision with general anesthesia, cardiopulmonary bypass, and endotracheal intubation; (3) received mechanical ventilation for at least 4 hours; (4) was conscious during mechanical ventilation; (5) experienced the transition from full ventilator support to a
From the Department of Heart Vascular Surgery, Yan’An Hospital Affiliated to Kunming Medical University, Kunming, Yunnan Province, China. Supported by the Science and Technology Agency of Yunnan Province (Grant No. 20080C016). Address reprint requests to Yaxiong Li, BS, Department of Heart Vascular Surgery, Yan’An Hospital Affiliated to Kunming Medical University, No. 245 East People Road, Kunming 650051, Yunnan Province, China. E-mail: [email protected] © 2015 Elsevier Inc. All rights reserved. 1053-0770/2601-0001$36.00/0 http://dx.doi.org/10.1053/j.jvca.2015.01.036
Subjects
Journal of Cardiothoracic and Vascular Anesthesia, Vol ], No ] (Month), 2015: pp ]]]–]]]
1
2
Drager Medical, Lubeck, Germany). For patients with a short (not overnight) anticipated mechanical ventilation time, no sedative or analgesic was used. In patients who needed mechanical ventilation overnight, intravenous infusion of midazolam, 0.03 to 0.2 mg/kg/h; sufentanil, 0.1 to 0.3 mg/kg; and vecuronium bromide, 0.02 to 0.05 mg/kg/h, was performed continuously. The infusion was stopped before extubation. Before extubation, the ventilation mode was set to continuous positive airway pressure. If blood gas results remained acceptable, aspiration of sputum was performed, and the tracheal tube was removed. The surgeon made the decision for extubation. Patients’ comfort was evaluated by the intensive care unit (ICU) physicians using a VAS.5 The patients completed the forms by themselves if they were able to or with the help of the medical personnel if necessary. In the authors’ hospital, ICU rooms contain 3 to 6 beds. Family members are not permitted to visit patients staying in the ICU. The patient-to-nurse ratio is never 43:1.
WANG ET AL
RESULTS
Patient Characteristics The study included 420 male and 380 female patients ranging in age from 18 to 70 years. Surgeries performed were heart valve replacement in 285 cases, coronary artery bypass grafting in 137 cases, and procedures for congenital heart diseases in 378 cases. Preoperative New York Heart Association class was I in 306 patients, II in 341 patients, III in 88 patients, and IV in 65 patients. American Society of Anesthesiologists class was I in 554 patients, II in 62 patients, III in 78 patients, and IV in 106 patients. The aortic cross-clamp time was 73.2 ⫾ 28.9 minutes. Mechanical ventilation time was 7.8 ⫾ 3.2 hours (range, 4-48 hours). After tracheal extubation, all patients were conscious and were able to remember their mechanical ventilation experience with normal verbal communication function (Table 1). Condition of patients was relatively stable (stable hemodynamics, acceptable blood gas values, and able to communicate) within 24 hours after extubation.
Evaluation Criteria The VAS method developed by the U.S. National Institutes of Health was used to evaluate the comfort of the patients. A VAS consists of a 10-cm line divided into 10 equal parts marked 0 to 10 from left to right: 0 to 2 indicates comfortable; 3 to 4, mildly uncomfortable; 5 to 6, moderately uncomfortable; 7 to 8, severely uncomfortable; and 9 to 10, extremely uncomfortable. The patients drew a mark on the line according to their subjective feelings. Recording patients’ experience after mechanical ventilation as well as factors affecting their comfort is a standard procedure in the authors’ hospital and is performed within 24 hours after extubation. The authors listed 14 factors that might affect the comfort of patients: tracheal intubation, aspiration of sputum, communication barriers, sleep disorders, patient-ventilator dyssynchrony, wound pain, dry mouth and thirst, limitation of motion, nervousness, anxiety and tension, surrounding environment, limited understanding of disease, lack of medical staff support, and financial burden. Each factor had 11 choices (0-10 scores), ranging from slight to severe. The patients were instructed to select a score to evaluate the factors according to their feelings, and this score indicated the degree of discomfort caused by this factor. As a routine procedure after extubation, the nursing staff asks 4 questions: (1) Do you think that the surgery was a painful experience? (2) If yes, which period was the most painful—before surgery, in the operation room, in the ICU, or back in the wards? (3) What was the most uncomfortable period during the ICU stay —during intubation or after extubation? (4) What was the most uncomfortable event? The VAS and the questionnaire about the 14 factors were completed as part of question 4 (Appendix A). Statistical Analysis Data were analyzed using SPSS for Windows version 13.0 (SPSS, Inc, Chicago, IL). Continuous variables were presented as means ⫾ SD, and categoric variables were reported as proportions. Factors affecting patients’ comfort were analyzed by multiple linear regression analysis; p values o 0.05 were considered statistically significant.
VAS Scores VAS scores are shown in Table 2. The mean VAS score of the patients with mechanical ventilation was 5.82 ⫾ 2.03. Of patients, 450% felt moderately uncomfortable, and 24% felt severely uncomfortable. No patient felt extremely uncomfortable or comfortable with mechanical ventilation. Causes of Patient Discomfort There were 14 causes of discomfort during mechanical ventilation evaluated including tracheal intubation, aspiration of sputum, communication barriers, sleep disorders, patientventilator dyssynchrony, wound pain, dry mouth and thirst, limitation of motion, nervousness, anxiety and tension, surrounding environment, limited understanding of the disease (ie, Table 1. Clinical Characteristics of Patients Who Underwent Cardiac Surgery and Mechanical Ventilation Clinical Characteristics
Sex, n (%) Male Female Age (y) Invasive ventilation time (h) Disease category, n (%) Heart valve replacement Coronary artery bypass grafting Congenital NYHA class, n (%) I II III IV ASA class, n (%) I II III IV
Value
420 (52.5) 380 (47.5) 38.6 ⫾ 18.9 7.8 ⫾ 3.2 285 (35.6) 137 (17.1) 378 (47.3) 306 341 88 65
(38.3) (42.6) (11.0) (8.1)
554 62 78 106
(69.1) (7.8) (9.8) (13.3)
Abbreviations: NYHA, New York Heart Association; ASA, American Society of Anesthesiologists.
3
COMPLAINTS DURING MECHANICAL VENTILATION
Table 2. Visual Analog Scale Scores During Mechanical Ventilation VAS Value
0-2 (comfortable) 3-4 (mildly uncomfortable) 5-6 (moderately uncomfortable) 7-8 (severely uncomfortable) 9-10 (extremely uncomfortable) Total
n
Percent (%)
0 156 450 194 0 800
0 19.5 56.3 24.2 0 100.0
Abbreviation: VAS, visual analog scale.
not understanding the pain and discomfort associated with the disease until experiencing it firsthand), lack of medical staff support, and financial burden. Comprehensive analysis of factors associated with discomfort of patients was performed by multiple linear regression analysis using the total comfort degree scores measured by the VAS as the dependent variable and the 14 causative factors as independent variables. Results showed that communication barriers, sleep disorders, aspiration of sputum, patientventilator dyssynchrony, dry mouth and thirst, physical constraint, nervousness, and poor environmental conditions were independently associated with patient comfort (Table 3).
DISCUSSION
Most patients who undergo cardiac surgery need to receive postoperative mechanical ventilation of varying durations in the ICU. Mechanical ventilation is associated with uncomfortable features, such as the inability to communicate, which can cause anxiety and distress in patients. There is a need to improve the mechanical ventilation experience after cardiac surgery. In the present study, the major complaints of patients during mechanical ventilation after cardiac surgery were retrospectively investigated and analyzed. Results showed that communication barriers, sleep disorders, aspiration of sputum, patientventilator dyssynchrony, dry mouth and thirst, physical constraint, nervousness, and lack of medical staff support were associated independently with patient comfort during mechanical ventilation after cardiac surgery. These results underlined
specific features that could be addressed specifically by nursing staff to improve patients’ comfort. Communication problems resulting from the inability to speak were among the factors causing distress to patients during mechanical ventilation. The results suggested that possibly psychological preparation before surgery could help alleviate the pain caused by being unable to speak. Training before surgery with sign language could be a good method, but it was not used in the present study. Nonspecific gestures could be difficult to understand by the nursing staff. Nevertheless, Wesley6 suggested that no matter how small the patients’ acts are, they are likely to be a scream for help. The intubation itself can cause pain, injuries, and distress to the patient.7,8 In the present study, about 61% of the patients believed that communication barriers had a significant influence on their degree of comfort, and 79% of the patients listed unsatisfied physiologic needs, such as dry mouth and thirst caused by lack of communication, as an important factor of their discomfort. The ICU, with its close monitoring, instrument alarm sounds, incandescent light, and moans from other patients, is an environment promoting discomfort.9,10 The feeling of loneliness resulting from being separated from family members and being unable to talk with the nurses could induce patients to become nervous and cause anxiety.9,10 Family members are not permitted to visit patients in most ICUs in China. In the present study, about 32.6% of the patients thought that anxiety was an important factor for discomfort. Exogenous and endogenous factors play an important role in patients’ discomfort.11 In the present study, endogenous factors such as dry mouth, thirst, communication barriers, nervousness, anxiety, and lack of medical staff support played important roles in patients’ discomfort. Further studies should be performed on new communication methods including the teaching of rudimentary sign language. Different means should be explored to improve some modifiable risk factors that were identified in the present study. Treatment and nursing actions such as aspiration of sputum, ventilator adjustment, tracheal intubation, and physical constraints are central to the discomfort experience of the patient,6 and close attention should be paid to the innovation research and application of more pleasant and comfortable treatments
Table 3. Multiple Linear Regression Analysis of Factors Affecting Patient Comfort During Mechanical Ventilation Unstandardized Coefficients Model
(Constant) Tracheal intubation Aspiration of sputum Patient-ventilator dyssynchrony Wound pain Dry mouth and thirst Limitation of motion Nervousness Communication barriers Sleep disorders Anxiety and tension Surrounding environment Limited understanding of disease Lack of medical personnel support Financial burden
Mean Value
B
SE
3.013 8.162 7.852 4.523 5.789 6.223 6.007 7.119 5.833 3.276 1.198 4.779 5.592 3.763
7.532 0.388 0.024 0.137 0.243 0.003 0.082 0.196 0.313 0.012 0.048 0.097 0.183 0.024 0.129
2.159 0.198 0.117 0.099 0.104 0.022 0.067 0.091 0.150 0.110 0.107 0.136 0.093 0.115 0.117
Standard Coefficient
T
p Value
0.218 0.023 0.152 0.244 0.015 0.113 0.263 0.248 0.011 0.045 0.084 0.189 0.022 0.111
3.488 0.208 1.963 1.386 2.351 0.158 1.231 0.221 2.079 0.106 0.450 0.711 1.972 2.1622 1.103
0.001 0.836 0.043 0.017 0.061 0.036 0.022 0.832 0.041 0.045 0.654 0.479 0.052 0.034 0.273
4
WANG ET AL
and nursing techniques. For aspiration of sputum, a careful surveillance protocol could be implemented to monitor closely sputum accumulation in the mouth, decreasing the risk of aspiration. Sleep disorders could be managed using drugs that emulate normal sleep such as dexmedetomidine. Patientventilator dyssynchrony could be reduced by the development of new ventilators that could detect the willingness of the patient to breathe on his or her own and to synchronize with it. Wound pain should be managed using the most appropriate analgesia tailored to each patient. Dry mouth could be managed by moisturization. Drugs and the management of other risk factors could be used to reduce anxiety and tension.12 These are only examples, and studies should be designed specifically to address them. However, some factors are nonmodifiable and are related to mechanical ventilation per se or to the reality of the patient or the healthcare system, such as limited understanding of the disease, lack of medical staff support, financial burden, tracheal intubation, communication barriers, and limited motions. Teaching before surgery may be a good approach to prepare patients and to reduce their discomfort. Medical staff should take the initiative to provide necessary information that enables patients to understand their disease, surgery, and nursing care. Previous studies showed that if mechanically ventilated patients are asked questions frequently (eg, whether they are cold, hot, or in pain; whether they need to drink water, to be turned over, or to defecate), better patient comfort could be achieved.13,14 Another way to improve patients’ comfort might be to improve the ICU environment and reduce adverse stimuli, such as the number of patients and staff and visual and auditory stimulation from equipment and other patients.15 Rescue equipment should be placed out of sight of patients. Lights during the night should be reduced to a minimum, and alarms of monitoring equipment should be turned down. Medical and nursing staff should speak in low voices. These simple actions should reduce the anxiety, discomfort, and distress of the patients on mechanical ventilation. In addition, patients on mechanical ventilation are prone to loneliness and fear, and patients regaining consciousness after coma or anesthesia are prone to cognitive disorders about time and place.16 The Chinese guidelines from the Chinese Medical Association Critical Illness Medicine Chapter17 for improved sedation and analgesia in critical illness recommend that (1) to improve the comfort degree and human-machine synchrony of mechanically ventilated patients, the patients can be given sedation and analgesia; (2) to improve safety and compliance of the diagnosis and surgical treatment, the patients can be given sedation and analgesia treatment preventively; (3) appropriate measures should be taken to improve the sleep quality of patients in the ICU, including improving the environment and nondrug therapy to relieve patients’ stress; and (4) drug-induced sleep could be considered for patients who still have sleep disorders after nondrug therapy.
Study Limitations The present study had some limitations. It was performed in patients without complications and with a short (not overnight) ventilation time and a smooth surgical process, which do not represent the entire population of patients in the ICU. In addition, the use of VAS scales was subjective. However, a VAS is the most reliable method for the evaluation of pain and can be used to quantify pain. As a subjective feeling, pain is a complex mix of physiologic and psychological feelings. The findings of the present study showed that there were various causes of discomfort in these patients and that pain was only one of them. However, because the other causes of distress also were relatively hard to quantify, the VAS was selected as the means of measurement. The questionnaire the authors used after extubation was not exhaustive. Some other factors of discomfort such as nausea and shivering were not included in this questionnaire and were not necessarily noted by the nurses, especially if they occurred between rounds or if they did not need medical attention. The use of specific sources of discomfort could lead to a bias if patients experienced a specific source of discomfort that was not listed. In addition, this was a retrospective study performed in a single center. The study did not look at long-term effects of mechanical ventilation on patients after cardiac surgery. Some factors such as age, length of time intubated, or length of time awake were not assessed. The study looked only at patients who survived their surgery. Because the patients could not communicate their distress and its source during intubation, the VAS was completed after extubation, which could have introduced a recall bias. The present study did not look at all the factors for optimal ventilation parameters that could reduce discomfort for patients. The authors could not exclude the possibility that sedation/analgesia could affect the VAS assessments by the patients; however, the data precluded any correction for this. Finally, because of the retrospective nature of the study, it had to be assumed that pain was managed as best as possible, but there was no way to assess this. CONCLUSIONS
Mechanical ventilation after open cardiac surgery under direct vision was a stressful and distressful period during hospitalization. The present study identified 8 independent factors (communication barriers, sleep disorders, aspiration of sputum, patient-ventilator dyssynchrony, dry mouth and thirst, physical constraint, nervousness, and poor environmental conditions) causing discomfort in patients during mechanical ventilation after cardiac surgery. Effective measures to decrease discomfort should be explored. APPENDIX A. SUPPLEMENTARY MATERIALS
Supplementary data associated with this article can be found in the online version at doi:10.1053/j.jvca.2015.01.036.
REFERENCES 1. Tobias JD: Is there an optimal mode of ventilation following cardiac surgery? Saudi J Anaesth 5:121-122, 2011 2. Pappalardo F, Franco A, Landoni G, et al: Long-term outcome and quality of life of patients requiring prolonged mechanical
ventilation after cardiac surgery. Eur J Cardiothorac Surg 25:548-552, 2004 3. Menzel LK: Factors related to the emotional responses of intubated patients to being unable to speak. Heart Lung 27:245-252, 1998
COMPLAINTS DURING MECHANICAL VENTILATION
4. DeLoach LJ, Higgins MS, Caplan AB, et al: The visual analog scale in the immediate postoperative period: Intrasubject variability and correlation with a numeric scale. Anesth Analg 86:102-106, 1998 5. Jeitziner MM, Schwendimann R, Hamers JP, et al: Assessment of pain in sedated and mechanically ventilated patients: An observational study. Acta Anaesthesiol Scand 56:645-654, 2012 6. Wesley RL: Nursing theories and models, ed 2. Springhouse, PA, Springhouse Corp, 1995 7. Coyer FM, Wheeler MK, Wetzig SM, et al: Nursing care of the mechanically ventilated patient: What does the evidence say? Part two. Intensive Crit Care Nurs 23:71-80, 2007 8. Finucane BT, Tsui BC, Santora AH: Mechanical ventilation and respiratory care. In: Principles of Airway Management, ed 4. New York, Springer pp 641-665, 2011 9. Novaes MA, Aronovich A, Ferraz MB, et al: Stressors in ICU: Patients’ evaluation. Intensive Care Med 23:1282-1285, 1997 10. Lusk B, Lash AA: The stress response, psychoneuroimmunology, and stress among ICU patients. Dimens Crit Care Nurs 24:25-31, 2005
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11. Samuelson KA: Unpleasant and pleasant memories of intensive care in adult mechanically ventilated patients—findings from 250 interviews. Intensive Crit Care Nurs 27:76-84, 2011 12. Richless CI: Current trends in mechanical ventilation. Crit Care Nurse 11:41-53, 1991 13. Turner P, Glass C, Grap MJ: Care of the patient requiring mechanical ventilation. Medsurg Nurs 6:68-73, 76, 94; quiz 77-78, 1997 14. Johnson MM, Sexton DL: Distress during mechanical ventilation: Patientsʼ perceptions. Crit Care Nurse 10:48-57, 1990 15. Gries ML, Fernsler J: Patient perceptions of the mechanical ventilation experience. Focus Crit Care 15:52-59, 1988 16. Wilson VS: Identification of stressors related to patients’ psychologic responses to the surgical intensive care unit. Heart Lung 16:267-273, 1987 17. Ma P, Liu J, Xi X, et al: Practice of sedation and the perception of discomfort during mechanical ventilation in Chinese intensive care units. J Crit Care 25:451-457, 2010
comfort included dry mouth, thirst, tracheal intubation, aspiration of sputum, communication barriers, limited mobility, fear/anxiety, patient-ventilator dyssynchrony, and poor environmental conditions. Of these factors, 8 were independent predictors of the visual analog scale score. Patients considered mechanical ventilation to be the worst part of their hospitalization. Conclusions: The study identified 8 independent factors causing discomfort in patients during mechanical ventilation after cardiac surgery. Clinicians should take appropriate measures and implement nursing interventions to reduce suffering, physical and psychologic trauma, and adverse psychologic responses and to promote recovery. & 2015 Elsevier Inc. All rights reserved.
M
spontaneous breathing trial; (6) was able to communicate with the hospital staff, and communication was not limited because of the use of a specific dialect or low education level; and (7) without any complications.
ECHANICAL VENTILATION is often necessary for patients with complicated postoperative treatment and respiratory dysfunction after cardiac surgery.1 Although methods vary among countries and centers, many patients need mechanical ventilation during and sometimes after cardiac surgery,2 and this is costly and uncomfortable for the patients. During ventilation, it is always difficult for patients to communicate with the medical staff. Their complaints cannot be handled correctly, which causes a painful experience for the patients and can have a negative impact on their recovery.3 The authors hypothesize that specific factors are responsible for the discomfort of mechanical ventilation. The authors performed a retrospective investigation of the major complaints of a group of patients with heart disease during mechanical ventilation after surgery. The aim of the present study is to summarize the physiologic and psychological needs of patients during mechanical ventilation. Analysis of patients’ comfort was performed using a visual analog scale (VAS), which is a psychometric scale for subjective characteristics that cannot be directly measured and used in postoperative pain analysis.4 The authors’ specially created survey with VAS is presented in Appendix A. This study may help medical personnel carry out treatments and medical care specifically to reduce the suffering caused by discomfort of mechanical ventilation.
KEY WORDS: cardiac surgery, comfort, ventilator, ICU
Clinical Techniques
METHODS
Anesthesia was induced using intravenous midazolam, 0.1 mg/kg; etomidate, 0.2 to 0.4 mg/kg; sufentanil, 0.5 to 1 mg/kg; and vecuronium bromide, 0.08 to 0.12 mg/kg. Orotracheal intubation was performed, and an anesthesia machine was connected for mechanical ventilation. Initial parameters were tidal volume of 8 to 10 mL/kg, respiratory frequency of 10 to 15 breaths/min, inspiratory/expiratory ratio of 1:2, and fraction of inspired oxygen of 60%. The parameters were adjusted according to the individual situation to obtain a satisfactory result of mechanical ventilation. For anesthesia maintenance, sufentanil, 0.3 to 1.0 mg/kg/h, was intravenously infused, sevoflurane, 1.5% to 2.5%, was inhaled, and a single dose of vecuronium bromide, 0.1 to 0.3 mg/kg, was administered (repeat dosing was allowed at minimal intervals of 45 min). Moderate hypothermic cardiopulmonary bypass was performed. After surgery, the mechanical ventilation mode was bilevel positive airway pressure, with parameters set for most patients as follows: pressure of 15 cmH2O, positive end-expiratory pressure of 5 cmH2O, and sensitivity of 2 L/min (Evita 4;
This retrospective study was performed in 800 consecutive patients who underwent cardiovascular surgery from January 2009 to December 2012 at the authors’ hospital. The study was approved by the ethical committee of the hospital, and the need for individual patient consent was waived by the committee. Inclusion criteria were as follows: (1) 418 years old; (2) underwent open cardiac surgery under direct vision with general anesthesia, cardiopulmonary bypass, and endotracheal intubation; (3) received mechanical ventilation for at least 4 hours; (4) was conscious during mechanical ventilation; (5) experienced the transition from full ventilator support to a
From the Department of Heart Vascular Surgery, Yan’An Hospital Affiliated to Kunming Medical University, Kunming, Yunnan Province, China. Supported by the Science and Technology Agency of Yunnan Province (Grant No. 20080C016). Address reprint requests to Yaxiong Li, BS, Department of Heart Vascular Surgery, Yan’An Hospital Affiliated to Kunming Medical University, No. 245 East People Road, Kunming 650051, Yunnan Province, China. E-mail: [email protected] © 2015 Elsevier Inc. All rights reserved. 1053-0770/2601-0001$36.00/0 http://dx.doi.org/10.1053/j.jvca.2015.01.036
Subjects
Journal of Cardiothoracic and Vascular Anesthesia, Vol ], No ] (Month), 2015: pp ]]]–]]]
1
2
Drager Medical, Lubeck, Germany). For patients with a short (not overnight) anticipated mechanical ventilation time, no sedative or analgesic was used. In patients who needed mechanical ventilation overnight, intravenous infusion of midazolam, 0.03 to 0.2 mg/kg/h; sufentanil, 0.1 to 0.3 mg/kg; and vecuronium bromide, 0.02 to 0.05 mg/kg/h, was performed continuously. The infusion was stopped before extubation. Before extubation, the ventilation mode was set to continuous positive airway pressure. If blood gas results remained acceptable, aspiration of sputum was performed, and the tracheal tube was removed. The surgeon made the decision for extubation. Patients’ comfort was evaluated by the intensive care unit (ICU) physicians using a VAS.5 The patients completed the forms by themselves if they were able to or with the help of the medical personnel if necessary. In the authors’ hospital, ICU rooms contain 3 to 6 beds. Family members are not permitted to visit patients staying in the ICU. The patient-to-nurse ratio is never 43:1.
WANG ET AL
RESULTS
Patient Characteristics The study included 420 male and 380 female patients ranging in age from 18 to 70 years. Surgeries performed were heart valve replacement in 285 cases, coronary artery bypass grafting in 137 cases, and procedures for congenital heart diseases in 378 cases. Preoperative New York Heart Association class was I in 306 patients, II in 341 patients, III in 88 patients, and IV in 65 patients. American Society of Anesthesiologists class was I in 554 patients, II in 62 patients, III in 78 patients, and IV in 106 patients. The aortic cross-clamp time was 73.2 ⫾ 28.9 minutes. Mechanical ventilation time was 7.8 ⫾ 3.2 hours (range, 4-48 hours). After tracheal extubation, all patients were conscious and were able to remember their mechanical ventilation experience with normal verbal communication function (Table 1). Condition of patients was relatively stable (stable hemodynamics, acceptable blood gas values, and able to communicate) within 24 hours after extubation.
Evaluation Criteria The VAS method developed by the U.S. National Institutes of Health was used to evaluate the comfort of the patients. A VAS consists of a 10-cm line divided into 10 equal parts marked 0 to 10 from left to right: 0 to 2 indicates comfortable; 3 to 4, mildly uncomfortable; 5 to 6, moderately uncomfortable; 7 to 8, severely uncomfortable; and 9 to 10, extremely uncomfortable. The patients drew a mark on the line according to their subjective feelings. Recording patients’ experience after mechanical ventilation as well as factors affecting their comfort is a standard procedure in the authors’ hospital and is performed within 24 hours after extubation. The authors listed 14 factors that might affect the comfort of patients: tracheal intubation, aspiration of sputum, communication barriers, sleep disorders, patient-ventilator dyssynchrony, wound pain, dry mouth and thirst, limitation of motion, nervousness, anxiety and tension, surrounding environment, limited understanding of disease, lack of medical staff support, and financial burden. Each factor had 11 choices (0-10 scores), ranging from slight to severe. The patients were instructed to select a score to evaluate the factors according to their feelings, and this score indicated the degree of discomfort caused by this factor. As a routine procedure after extubation, the nursing staff asks 4 questions: (1) Do you think that the surgery was a painful experience? (2) If yes, which period was the most painful—before surgery, in the operation room, in the ICU, or back in the wards? (3) What was the most uncomfortable period during the ICU stay —during intubation or after extubation? (4) What was the most uncomfortable event? The VAS and the questionnaire about the 14 factors were completed as part of question 4 (Appendix A). Statistical Analysis Data were analyzed using SPSS for Windows version 13.0 (SPSS, Inc, Chicago, IL). Continuous variables were presented as means ⫾ SD, and categoric variables were reported as proportions. Factors affecting patients’ comfort were analyzed by multiple linear regression analysis; p values o 0.05 were considered statistically significant.
VAS Scores VAS scores are shown in Table 2. The mean VAS score of the patients with mechanical ventilation was 5.82 ⫾ 2.03. Of patients, 450% felt moderately uncomfortable, and 24% felt severely uncomfortable. No patient felt extremely uncomfortable or comfortable with mechanical ventilation. Causes of Patient Discomfort There were 14 causes of discomfort during mechanical ventilation evaluated including tracheal intubation, aspiration of sputum, communication barriers, sleep disorders, patientventilator dyssynchrony, wound pain, dry mouth and thirst, limitation of motion, nervousness, anxiety and tension, surrounding environment, limited understanding of the disease (ie, Table 1. Clinical Characteristics of Patients Who Underwent Cardiac Surgery and Mechanical Ventilation Clinical Characteristics
Sex, n (%) Male Female Age (y) Invasive ventilation time (h) Disease category, n (%) Heart valve replacement Coronary artery bypass grafting Congenital NYHA class, n (%) I II III IV ASA class, n (%) I II III IV
Value
420 (52.5) 380 (47.5) 38.6 ⫾ 18.9 7.8 ⫾ 3.2 285 (35.6) 137 (17.1) 378 (47.3) 306 341 88 65
(38.3) (42.6) (11.0) (8.1)
554 62 78 106
(69.1) (7.8) (9.8) (13.3)
Abbreviations: NYHA, New York Heart Association; ASA, American Society of Anesthesiologists.
3
COMPLAINTS DURING MECHANICAL VENTILATION
Table 2. Visual Analog Scale Scores During Mechanical Ventilation VAS Value
0-2 (comfortable) 3-4 (mildly uncomfortable) 5-6 (moderately uncomfortable) 7-8 (severely uncomfortable) 9-10 (extremely uncomfortable) Total
n
Percent (%)
0 156 450 194 0 800
0 19.5 56.3 24.2 0 100.0
Abbreviation: VAS, visual analog scale.
not understanding the pain and discomfort associated with the disease until experiencing it firsthand), lack of medical staff support, and financial burden. Comprehensive analysis of factors associated with discomfort of patients was performed by multiple linear regression analysis using the total comfort degree scores measured by the VAS as the dependent variable and the 14 causative factors as independent variables. Results showed that communication barriers, sleep disorders, aspiration of sputum, patientventilator dyssynchrony, dry mouth and thirst, physical constraint, nervousness, and poor environmental conditions were independently associated with patient comfort (Table 3).
DISCUSSION
Most patients who undergo cardiac surgery need to receive postoperative mechanical ventilation of varying durations in the ICU. Mechanical ventilation is associated with uncomfortable features, such as the inability to communicate, which can cause anxiety and distress in patients. There is a need to improve the mechanical ventilation experience after cardiac surgery. In the present study, the major complaints of patients during mechanical ventilation after cardiac surgery were retrospectively investigated and analyzed. Results showed that communication barriers, sleep disorders, aspiration of sputum, patientventilator dyssynchrony, dry mouth and thirst, physical constraint, nervousness, and lack of medical staff support were associated independently with patient comfort during mechanical ventilation after cardiac surgery. These results underlined
specific features that could be addressed specifically by nursing staff to improve patients’ comfort. Communication problems resulting from the inability to speak were among the factors causing distress to patients during mechanical ventilation. The results suggested that possibly psychological preparation before surgery could help alleviate the pain caused by being unable to speak. Training before surgery with sign language could be a good method, but it was not used in the present study. Nonspecific gestures could be difficult to understand by the nursing staff. Nevertheless, Wesley6 suggested that no matter how small the patients’ acts are, they are likely to be a scream for help. The intubation itself can cause pain, injuries, and distress to the patient.7,8 In the present study, about 61% of the patients believed that communication barriers had a significant influence on their degree of comfort, and 79% of the patients listed unsatisfied physiologic needs, such as dry mouth and thirst caused by lack of communication, as an important factor of their discomfort. The ICU, with its close monitoring, instrument alarm sounds, incandescent light, and moans from other patients, is an environment promoting discomfort.9,10 The feeling of loneliness resulting from being separated from family members and being unable to talk with the nurses could induce patients to become nervous and cause anxiety.9,10 Family members are not permitted to visit patients in most ICUs in China. In the present study, about 32.6% of the patients thought that anxiety was an important factor for discomfort. Exogenous and endogenous factors play an important role in patients’ discomfort.11 In the present study, endogenous factors such as dry mouth, thirst, communication barriers, nervousness, anxiety, and lack of medical staff support played important roles in patients’ discomfort. Further studies should be performed on new communication methods including the teaching of rudimentary sign language. Different means should be explored to improve some modifiable risk factors that were identified in the present study. Treatment and nursing actions such as aspiration of sputum, ventilator adjustment, tracheal intubation, and physical constraints are central to the discomfort experience of the patient,6 and close attention should be paid to the innovation research and application of more pleasant and comfortable treatments
Table 3. Multiple Linear Regression Analysis of Factors Affecting Patient Comfort During Mechanical Ventilation Unstandardized Coefficients Model
(Constant) Tracheal intubation Aspiration of sputum Patient-ventilator dyssynchrony Wound pain Dry mouth and thirst Limitation of motion Nervousness Communication barriers Sleep disorders Anxiety and tension Surrounding environment Limited understanding of disease Lack of medical personnel support Financial burden
Mean Value
B
SE
3.013 8.162 7.852 4.523 5.789 6.223 6.007 7.119 5.833 3.276 1.198 4.779 5.592 3.763
7.532 0.388 0.024 0.137 0.243 0.003 0.082 0.196 0.313 0.012 0.048 0.097 0.183 0.024 0.129
2.159 0.198 0.117 0.099 0.104 0.022 0.067 0.091 0.150 0.110 0.107 0.136 0.093 0.115 0.117
Standard Coefficient
T
p Value
0.218 0.023 0.152 0.244 0.015 0.113 0.263 0.248 0.011 0.045 0.084 0.189 0.022 0.111
3.488 0.208 1.963 1.386 2.351 0.158 1.231 0.221 2.079 0.106 0.450 0.711 1.972 2.1622 1.103
0.001 0.836 0.043 0.017 0.061 0.036 0.022 0.832 0.041 0.045 0.654 0.479 0.052 0.034 0.273
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WANG ET AL
and nursing techniques. For aspiration of sputum, a careful surveillance protocol could be implemented to monitor closely sputum accumulation in the mouth, decreasing the risk of aspiration. Sleep disorders could be managed using drugs that emulate normal sleep such as dexmedetomidine. Patientventilator dyssynchrony could be reduced by the development of new ventilators that could detect the willingness of the patient to breathe on his or her own and to synchronize with it. Wound pain should be managed using the most appropriate analgesia tailored to each patient. Dry mouth could be managed by moisturization. Drugs and the management of other risk factors could be used to reduce anxiety and tension.12 These are only examples, and studies should be designed specifically to address them. However, some factors are nonmodifiable and are related to mechanical ventilation per se or to the reality of the patient or the healthcare system, such as limited understanding of the disease, lack of medical staff support, financial burden, tracheal intubation, communication barriers, and limited motions. Teaching before surgery may be a good approach to prepare patients and to reduce their discomfort. Medical staff should take the initiative to provide necessary information that enables patients to understand their disease, surgery, and nursing care. Previous studies showed that if mechanically ventilated patients are asked questions frequently (eg, whether they are cold, hot, or in pain; whether they need to drink water, to be turned over, or to defecate), better patient comfort could be achieved.13,14 Another way to improve patients’ comfort might be to improve the ICU environment and reduce adverse stimuli, such as the number of patients and staff and visual and auditory stimulation from equipment and other patients.15 Rescue equipment should be placed out of sight of patients. Lights during the night should be reduced to a minimum, and alarms of monitoring equipment should be turned down. Medical and nursing staff should speak in low voices. These simple actions should reduce the anxiety, discomfort, and distress of the patients on mechanical ventilation. In addition, patients on mechanical ventilation are prone to loneliness and fear, and patients regaining consciousness after coma or anesthesia are prone to cognitive disorders about time and place.16 The Chinese guidelines from the Chinese Medical Association Critical Illness Medicine Chapter17 for improved sedation and analgesia in critical illness recommend that (1) to improve the comfort degree and human-machine synchrony of mechanically ventilated patients, the patients can be given sedation and analgesia; (2) to improve safety and compliance of the diagnosis and surgical treatment, the patients can be given sedation and analgesia treatment preventively; (3) appropriate measures should be taken to improve the sleep quality of patients in the ICU, including improving the environment and nondrug therapy to relieve patients’ stress; and (4) drug-induced sleep could be considered for patients who still have sleep disorders after nondrug therapy.
Study Limitations The present study had some limitations. It was performed in patients without complications and with a short (not overnight) ventilation time and a smooth surgical process, which do not represent the entire population of patients in the ICU. In addition, the use of VAS scales was subjective. However, a VAS is the most reliable method for the evaluation of pain and can be used to quantify pain. As a subjective feeling, pain is a complex mix of physiologic and psychological feelings. The findings of the present study showed that there were various causes of discomfort in these patients and that pain was only one of them. However, because the other causes of distress also were relatively hard to quantify, the VAS was selected as the means of measurement. The questionnaire the authors used after extubation was not exhaustive. Some other factors of discomfort such as nausea and shivering were not included in this questionnaire and were not necessarily noted by the nurses, especially if they occurred between rounds or if they did not need medical attention. The use of specific sources of discomfort could lead to a bias if patients experienced a specific source of discomfort that was not listed. In addition, this was a retrospective study performed in a single center. The study did not look at long-term effects of mechanical ventilation on patients after cardiac surgery. Some factors such as age, length of time intubated, or length of time awake were not assessed. The study looked only at patients who survived their surgery. Because the patients could not communicate their distress and its source during intubation, the VAS was completed after extubation, which could have introduced a recall bias. The present study did not look at all the factors for optimal ventilation parameters that could reduce discomfort for patients. The authors could not exclude the possibility that sedation/analgesia could affect the VAS assessments by the patients; however, the data precluded any correction for this. Finally, because of the retrospective nature of the study, it had to be assumed that pain was managed as best as possible, but there was no way to assess this. CONCLUSIONS
Mechanical ventilation after open cardiac surgery under direct vision was a stressful and distressful period during hospitalization. The present study identified 8 independent factors (communication barriers, sleep disorders, aspiration of sputum, patient-ventilator dyssynchrony, dry mouth and thirst, physical constraint, nervousness, and poor environmental conditions) causing discomfort in patients during mechanical ventilation after cardiac surgery. Effective measures to decrease discomfort should be explored. APPENDIX A. SUPPLEMENTARY MATERIALS
Supplementary data associated with this article can be found in the online version at doi:10.1053/j.jvca.2015.01.036.
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